Towards next generation power grid transformer for renewables: Technology review

This paper develops a technical framework for the next‐generation power grid transformer (NGPGT) for grid renewables. This framework is structured to overcome the environmental challenges produced by the explosive use of nonrenewable base energy generation sources. The use of these sources cannot meet the required electricity for the world's growing community due to their availability, cost, and lack of flexibility. However, modern energy systems focus on the use of renewable energy sources, where the grid transformer's interaction plays an essential role in their generation, transmission, and distribution. The lack of centralization, local monitoring, interoperability, authenticity, and precise bi‐directional flow may limit the application of current framework power grid transformers in grid renewables. In this paper, a new technical framework, called NGPGT, is developed by introducing some extended features for addressing the challenges shown in current‐generation transformers. This is structured by enabling some advanced technical features with the existing framework, which includes automatic condition monitoring, intelligent inverters, edge computing, automatic controlling, and intelligent management. This paper also illustrates the benefits and scope of the NGPGT compared to the existing transformer by assembling essential requirements and obligatory components. Additionally, this paper highlights a few difficulties of implementing NGPGT in terms of operational, communication, energy management, and economic points of view, which may enable further research scopes for the researchers.


INTRODUCTION
Renewable energy sources (RESs) 1 are sustainable over time scales that are of interest to human civilization, essentially perpetually, and serve as an environmentally benign alternative to finite fossil fuels. 2 The imperative incorporation of RESs into modern power grids is grounded in several interrelated motivations.These sources offer a sustainable means of electricity generation to significantly mitigate the greenhouse gas emissions and environmental degradation.It diversifies the energy portfolio, reducing dependence on finite fossil fuels and enhancing energy security. 3he distributed and decentralized nature of RESs also fosters grid resilience as it diminishes vulnerability to centralized failures.It provides a mechanism for meeting the rising energy demands of a burgeoning global population while mitigating the geopolitical tensions associated with fossil fuel supply.They offer long-term cost savings due to abundant, freely available fuel sources and diminished price volatility.The variability of RESs, however, necessitates advanced grid management and energy storage technologies to ensure grid stability.
Thus, the integration of RESs not only aligns with sustainability and environmental goals but also embodies an essential strategy for ensuring the reliability and adaptability of modern power grids.The integration of RESs into contemporary power grids has ushered in a paradigm shift, significantly altering the grid's operational dynamics. 4One pivotal component that underpins this transformation is the transformer, which traditionally serves as an interface for voltage conversion, transmission, and distribution within the grid.However, contemplating a hypothetical scenario where transformers are absent, a host of operational challenges emerge, each of which carries profound consequences.The foremost of these challenges is voltage regulation.In a grid devoid of transformers, the inherent variability of RESs would directly impinge on grid voltages.Without the buffering effect provided by transformers, voltage fluctuations would propagate swiftly, compromising the grid's stability and the quality of the power supply. 5Here, the consequences would manifest in the form of electrical equipment damage, reduced grid reliability, and potential service interruptions, undermining the grid's ability to meet the stringent demands of modern society (Figure 1).
Moreover, the absence of transformers would exacerbate issues of grid integration, particularly in terms of distributed energy resources. 7The precise matching of RES-generated electricity with load demands would become exceedingly challenging, requiring intricate coordination mechanisms.This could lead to inefficiencies, curtailment of excess energy, and potential grid congestion, with subsequent economic ramifications and environmental opportunity costs. 8Additionally, grid resilience would be severely tested in the face of line faults and short circuits, as transformers are instrumental in isolating and protecting segments of the grid. 9Furthermore, the transformational benefits of interconnecting diverse energy resources, critical to enhancing grid reliability and optimizing the use of RESs, would be compromised.Without transformers, the potential for linking disparate energy sources, be they solar, wind, or geothermal, can be hampered.This could hinder the diversification of the energy mix and the efficient utilization of varying energy resources, ultimately limiting the grid's ability to adapt to changing conditions and evolving energy needs.
1][12][13] Advanced sensors and monitoring equipment, when integrated with transformers, enable real-time data acquisition, facilitating F I G U R E 1 Traditional power grid. 6rid optimization and predictive maintenance. 14Automation streamlines the operation of the grid, allowing for swift responses to fluctuating energy inputs from RESs.This is particularly crucial in harnessing the full potential of solar and wind power, which exhibit variable generation patterns.Further, the efficiency gains in renewable power grids can be achieved through the deployment of transformers.By stepping up voltage levels for long-distance transmission, transformers reduce resistive losses, enhancing energy efficiency. 5Additionally, modern transformers are designed with advanced materials and technologies that further minimize losses, contributing to the overall efficiency of the grid.Improved efficiency is of paramount significance in renewable power grids, where the variability of energy sources necessitates the optimization of every component to ensure resource utilization to its fullest potential. 15n the contrary, the presence of transformers enables advanced applications like remote monitoring and control, which are instrumental in grid management and maintenance.However, the transformers are subject to design and operational challenges that stem from the intricate interplay of engineering, environmental, and performance factors.Design challenges encompass optimizing the core and winding materials, cooling systems, and insulation to achieve an ideal balance between efficiency, size, and cost.Operational challenges emerge from diverse factors, including load fluctuations, harmonics, and transient overvoltage's, which can lead to core saturation, increased losses, and overheating. 16While the environmental factors, such as temperature extremes and humidity, further influence transformer performance.Addressing environmental concerns by reducing the use of insulating oils and adopting more sustainable materials is an emerging design challenge.In operation, transformers face challenges related to aging and reliability, where factors like thermal stress and partial discharge can degrade their performance over time. 17Ensuring reliable and efficient operation under varying loads and voltage conditions, as well as handling transient disturbances, is an ongoing challenge in power system management.Additionally, grid integration challenges arise as we strive to incorporate RESs with variable outputs, requiring transformers to adapt to fluctuating power flow patterns.Addressing these multifaceted challenges through innovative designs, materials, and operational strategies is the main motivation in the field of power systems and transformer technology.
These challenges in transformer design and operation are primarily generated by the dynamic and evolving nature of power systems and the quest for improved performance and sustainability. 18The environmental concerns motivate the search for alternative insulating materials, as traditional oils raise ecological issues.Aging and reliability challenges emerge from the harsh operational conditions that transformers endure, including temperature variations and voltage transients, leading to degradation over time and the grid integration challenges result from the increasing penetration of RESs with variable outputs, creating the need for transformers that can handle dynamic power flows and maintain grid stability. 19These challenges emerge from the continuous drive to make power systems more efficient, sustainable, and resilient to accommodate the evolving energy landscape and emerging technologies.

Literature review
The solid-state transformers (SSTs) are a promising technology aimed at enhancing the efficiency, flexibility, and controllability of power distribution systems. 20Researchers have been actively exploring various design approaches, with a focus on advancing the performance, reliability, and integration of SSTs with RESs. 21Notably, new semiconductor technologies are being used to improve the power handling of SSTs.These include wide-bandgap materials like silicon carbide (SiC) and gallium nitride (GaN). 22Protocols and control schemes, often based on digital signal processing and power electronics, play a pivotal role in regulating voltage levels, power quality, and grid synchronization.Furthermore, innovative frameworks, including modular and multi-level topologies, are being developed to optimize the functionality and adaptability of SSTs in both medium-and low-voltage applications.This dynamic research landscape in the field of SST design reflects the ongoing efforts to enable a more resilient and sustainable power infrastructure, addressing the pressing challenges of modern energy systems. 20he SST offers several strengths that make it particularly suited to addressing the unique challenges in grid renewables.It is compact and modular design allows for efficient integration of RESs with varying voltage and frequency outputs, enhancing grid stability and accommodating distributed generation.The SSTs also exhibit high controllability and fast response capabilities, crucial for managing the intermittency and unpredictability of renewable resource. 23However, SSTs do come with limitations, including high initial costs due to advanced semiconductor materials and complex control systems, which might hinder their widespread adoption.Furthermore, issues related to heat dissipation and potential reliability concerns must be carefully addressed.Nevertheless, given the evolving research landscape and the potential TA B L E 1 Summary of important surveys.

Opportunities and challenges of integration
for cost reduction in the future, SSTs hold promise as a valuable tool in enabling the seamless integration of RESs into the grid, ultimately advancing the transition to a more sustainable and resilient energy infrastructure. 11everal research gaps exist in the field of SSTs that continue to challenge their widespread adoption and effectiveness.One prominent gap is the need for standardized testing and validation protocols for SSTs to ensure their reliability and performance under various operating conditions. 24Robust modeling and simulation tools, as well as experimental verification methodologies, are lacking to assess SST behavior comprehensively.Another crucial research area involves cost reduction, as SSTs currently involve high initial capital expenses due to the use of advanced semiconductor materials, which limits their commercial viability. 25Some strategies for achieving more cost-effective designs, such as innovative material selection or manufacturing processes, require further investigation.Additionally, enhancing the SST's ability to handle high-power applications, improving its thermal management systems, and exploring fault-tolerant designs remain research challenges.Furthermore, the development of standardized communication and control protocols for integrating SSTs into existing grid infrastructures is essential.Addressing these research gaps is imperative to unlocking the full potential of SSTs and accelerating their adoption in modern power distribution systems. 26o advance the development of next-generation transformers, several key research areas demand further exploration.First and foremost, the integration of advanced materials and manufacturing techniques is essential to enhance efficiency and reduce environmental impact. 27Smart materials like amorphous metals or superconductors could significantly improve transformer performance and reduce losses. 28Additionally, research into compact and modular transformer designs is needed to adapt to changing grid architectures and accommodate distributed energy resources effectively.Developing intelligent control and monitoring systems, incorporating elements of the Internet of Things (IoT) and machine learning, is crucial to optimizing next-generation transformer operation, prediction. 29Furthermore, cybersecurity is essential to protect these digitally connected transformers from potential threats. 30Lastly, exploring sustainable end-of-life management and recycling solutions can be vital to reducing the environmental footprint of transformers.Research efforts in smart materials, design, intelligent control, cybersecurity, and sustainability are critical to advancing the evolution of next-generation transformers for supporting the ongoing transformation of power distribution systems (Table 1).

Aim and contributions
This work consolidates and synthesizes the existing research and knowledge regarding power grid transformers, renewable energy integration, and emerging transformer technologies.By comprehensively analyzing the available literature, we aim to provide readers with a clear understanding of the current state-of-art in the field power transformer.Here, we identify and articulate the critical challenges faced by traditional transformers when accommodating RESs.These challenges encompass aspects of grid resilience, environmental sustainability, and energy efficiency.By synthesizing the existing knowledge on these issues, we aim to create a holistic perspective on the problems that need to be addressed.The analysis of this work seeks to encompass a wide spectrum of technical, operational, and economical aspects associated with transformers.The main contributions of this study are as follows: (i) This study reviews the current state of transformer concepts in the power grid (microgrid, smart grid, and VPP) systems and proposes a comprehensive concept of next-generation transformer for the grid renewables.
(ii) This works highlights the challenges of conventional grid transformer in terms of technical, operational, and economical aspects, and deliver a solution through the enabling of next-generation grid transformer.
(iii) A framework for next-generation power grid transformer is developed by enabling the extended features such as IoT, machine learning, which may have the possibility of accumulating over the existing power grid transformer challenges and causes of problems.
(iv) This study also covers the trends and future integration challenges of next-generation transformer that may enable another research area for conducting future work.
The insights presented in this paper is important to the engineers with critical information to make informed decisions regarding the modernization of power grid transformers.By understanding the challenges and innovations in this field, they can contribute to more efficient, sustainable, and resilient grid systems.For the purpose of designing effective and dependable power grids, this work can be essential to comprehend how the integration of RESs affects transformers.This paper offers insights into these challenges, equipping engineers to work effectively in this evolving landscape.Finally, this paper underscores the urgency of transitioning to next-generation transformers for RESs integration.Engineers who are committed to making a global impact by addressing the challenges of clean energy integration will find a compelling call to action in this review.

Organization
The remaining sections of our article are organized as follows: A total of seven sections make up the description of the study that is carried out.Section 2 provides an overview of microgrids, smart grids, and virtual power plants and describes the core idea and concept of a renewable integrated power grid.Following Section 3, which introduces the existing transformer fundamentals and frameworks.The critical requisites of a next-generation power grid transformer that are covered in Section 4. Section 5 is about transitioning to next-generation transformers and is separated into subsections that describe the featured components, conditions, and future trends for the next-generation transformer.The challenges of integrating the transformer with grid renewables are highlighted in Section 6.Finally, Section 7 summarizes the key findings and implications of this paper.

Microgrid
The power distribution community is in charge of administering the enormous and complex power system.The connectivity has been, and therefore will continue to be, constituted by sharing a variety of renewable sources of energy.Future electrical systems will include a variety of generators and energy consumers distributed over large areas and linked to a central control network.Electric power could be delivered in a range of ways, but consumers like it to be of the utmost quality, minimum cost, and most reliable. 40A microgrid is an innovative approach to ensuring a steady supply of electricity in a power grid.It is a comparatively tiny electricity grid that can work alone or in tandem with other small power system.Figure 2 demonstrates an overview of a microgrid.Microgrid has two kinds of connected working modes: one is network connection mode, which means that each of these features, such as frequencies, voltage, and power flow, is directly regulated by the power network and exhibits dependable and responsive characteristics. 41Another one is that it may also be separate from the main grid during an exigency, such as a transmission line fault or uncertainty, and as an independent power unit known as a stand-alone MG, where it would be responsible for its own control of the voltage, current, or frequency profile.Microgrids are used for power trading in two different circumstances: (i) when there is an overflow of the potential energy supply from distributed energy resources (DERs).(ii) When the output of the DERs exceeds the consumption of electricity on the grid. 42The design architecture may enable both the operating and regulation modes for an MG to produce the needed power for consumption effectively and efficiently.DERs, storage devices, and traditional control and monitoring systems make up a typical MG setup.
F I G U R E 2 Overview of microgrid.

Components of energy sources
(i) Traditional energy sources: Power may be generated using several sources of energy, like hydrocarbons, natural gas, nuclear energy, and oil.More than three-quarters of the world's energy originates from the following sources: Natural gas may be used in a generator that runs on gas coupled to an SG since the combustion products include very few tars or particles.Open-cycle gas turbines (OCGTs), which may run on gas or oil distillate, are the most prevalent form of a gas-fired plant.Because the gasoline is fed to the turbine, such structures have a much quicker response time.Synthetic gases such as hydrogen (H2), carbon monoxide (CO), and a small quantity of carbon dioxide may be made using solar energy.However, gases ejected from a gas turbine result in a significant dissipation of heat into the environment. 43eat energy is transformed from fossil fuels into high-pressure, high-temperature steam, which is then used for producing power in traditional power plants.It is common practice in coal-fired power plants to first heat the combustion chamber with distillate oil before injecting the coal.Coal-fired power stations burn bituminous coal, sub-bituminous coal, or lignite.When the temperature is exactly perfect, coal crushed to dust in ball mills is blasted into the chamber for the burning of fuel, where the pulverized fuel burns and produces heat. 44Coal combustion heat is utilized to convert water to high-pressure steam, which is subsequently applied to power an electrical generator.
The synchronous generator is one of the most crucial components of energy distribution channels.It can generate up to 40 kV of power, which may be increased even more by using a transformer to send the signal via a high-or extra-high-voltage transmission line. 45Synchronous generators are frequently used in varying wind turbines due to their low-rotating synchronized revolutions, which produce grid-frequency electricity.The generator can be powered by steam, hydroelectric, and gas turbines.In microgrids with lower strength levels, diesel engines can be utilized to power generators.Prior to the examination, modeling can predict the behavior of the SG in many eventualities, including overload and failure mechanisms. 46The following four basic methodologies are used to model SGs in general: (i) Frame dq0.(ii) Approach to the winding function (WFA) (iii) model of the phase domain (PDM) (iv) The technique of finite elements (FEM) is both dependable and secure.
(ii) Renewable energy sources: Renewable energy sources (RESs) are growing in popularity as people become more conscious of the need to conserve energy for the future.Fossil fuels are currently mostly used to heat and power our homes, as well as to fuel our cars.Coal, oil, and natural gas are convenient for providing our energy demands, but there is a finite quantity of these energies on the planet. 47The earth's heat, biomass, and plants are all renewable energy sources that nature constantly regenerates, in contrast to the wind, sun, and water.It not only relieves the strain on nonrenewable sources of energy but also gives consumers the opportunity to save money.
Solar energy is the most eco-friendly and abundant type of renewable energy.It can be used for a multitude of purposes, including producing power, lighting or creating a pleasant indoor environment, and heating water for home, commercial, or industrial applications. 49As a result of advances in solar technology and global developments in the structure of the electric sector, a substantial solar electric business for powering urban grid-connected homes and buildings arose over the previous decade.Due to the lack of moving parts and heat stress, solar energy systems are very easy to maintain and operate. 50Many photovoltaic (PV) solar cells, which are generally formed of semiconductor material, make up a photovoltaic (PV) solar system.The photovoltaic (PV) system generates electricity by harnessing the sun's energy. 51Batteries are unnecessary for PV systems that are connected to the power grid.However, some grid-connected systems use them for emergency backup power.This photovoltaic system converts 7-17% of light energy into electricity.Solar penetration might reach 27% by 2050, according to the International Energy Agency, making it the greatest global sustainable source of power. 52he wind's renewable energy, nonpolluting nature, long-term viability, and omnipresent nature make it a globally sought-after technology. 53A wind turbine may be thought of as the polar opposite of a fan.Electricity is used to create wind in a fan.Wind turbines, on the other hand, utilize the wind to generate power.Wind farms appear to have achieved their primary goal of generating electricity with a minimal carbon footprint while also contributing to natural capital. 54t is regarded as operating at a constant or fixed speed.Fixed-speed wind turbines with direct grid-coupled squirrel cage induction generators connected to the wind turbine rotor through gearboxes are one of the most often utilized wind farm ideas in power systems. 55Because a squirrel cage induction generator uses reactive power, compensating capacitors are used to provide the magnetizing current of the induction generator, thereby boosting efficiency.Despite their availability, wind farms can make a one-time, possibly insignificant contribution while additional efforts are made to generate a clean energy supply and better control demand. 56ecause of technical breakthroughs in offshore engineering and the rising cost of traditional energy, offshore energy resources will become economically feasible in the next few years.Tidal dams or barrages are now regarded as certain energy sources capable of generating electricity on a large scale. 57To satisfy the sustainable development scenario (SDS), this technology must be deployed swiftly, with a 23% yearly increase required until 2030.The predictability of the tide in the face of any weather change is a benefit of this strategy.Furthermore, the density of water is 800 times higher than that of wind.Nearly 12 knots of water and 110 knots of wind provide the same amount of power.The most often used technique is tidal barrage systems.One-or two-way turbines can harness the power of ebb and flood tides, respectively, to power the facility.If the water level on either side of the barrage is the same, electricity will not be produced. 8Tidal stream turbines (TST), which are quite similar to wind turbines, are the second most common method.TSTs are more effective than onand off-shore wind turbines due to their smaller size and less noticeable visual impact, both of which are achieved by placing the majority of the device underwater.Based on the ebb and flow of the tides, this method transforms the kinetic energy of the water into electricity. 58The turbine absorbs the kinetic energy of the water, which then produces electricity.In order to generate electricity, hybrid generators use both tidal-range and steam generators.Dynamic tidal power, a mix of tidal range and current power generation, is also becoming more popular.TST is the most promising technique of them all since it ignores the detrimental environmental impacts of barrages. 59iomass is a type of fuel made from organic resources like scrap lumber or tree branches, straw, and animal manure.It is the sole renewable source of carbon, and it may be used to create a variety of products.Moreover, biomass is the term for the organic waste produced by plants during photosynthesis, making them all green energy sources.Biomass can be utilized to produce electricity in three different ways: (i) The fuel can be burned; (ii) degraded by microorganisms; (iii) transformed into a gas or liquid fuel. 60It is the same as if we were using fossil fuels.The term thermal generation refers to the process of generating energy by burning materials.Methane is burned in certain biomass facilities to create power.Instead of steam, the turbine is spun by the results of burning methane. 61A generator is driven by the spinning of the turbine, much as it is with solid biomass.An important feature is sometimes overlooked: biomass should be burned as close to its source as possible, as fuel expenses and carbon emissions from long-distance transportation can considerably raise carbon emissions from fossil fuels. 62Biomass plants, unlike other renewable energy sources, can create electricity continuously.They do not rely on sporadic factors like the wind or the sun.So, biomass-based electricity is reliable.Country-wise electricity generation through renewable energy sources like hydropower, wind, geothermal, and solar is as shown in Table 2.

Smart grid
In the modern world, enhancing energy consumption and reliance on fossil fuels have become major global concerns.So, there is indeed a growing trend to employ renewable energy sources (RES) to generate electricity.The power system faces significant challenges as a result of the high penetration of renewable energy sources and energy management.For a prolonged day, a conventional and centralized system for the transmission and distribution of electrical energy is being used.The world is currently developing and in the future, the global demand for energy will increase day by day.
Approaches that require energy and management are totally dependent on the power grid. 63In this concept, the smart grid, also known as the intelligent grid, is a new solution for demand and energy management for the next-generation network compared to the conventional network.The modern electrical system has the potential to be changed by smart grids.The term smart grid refers to a communication-based approach to power system management.It is a two-way communication interface that provides the grid to the consumer and the consumer to the grid. 64Figure 3 illustrates the overview of the smart grid.Distributed intelligence, communication technology, and digital control techniques are crucial attributes of smart grids. 65The smart grid has distinctive features, including ICT-based monitoring, self-healing methods, decentralized generations, smart meters, 5G wireless networks, power grids, virtual power the integrity of renewable energy and in particular, the IT security of grid networks. 66The primary objectives of these smart power networks are to improve efficiency, reliability, flexibility, and service monitoring. 67The purposes of smart grid infrastructure are to increase the efficiency of power grids while maintaining their security and reliability, transform existing power grids into interactive utility networks and remove technical barriers to large-scale installation and full integration of renewable energy sources. 68

Smart power generation
It is a one-of-a-kind, cutting-edge mix of characteristics that paves the way for a more sustainable, dependable, and cheap energy infrastructure.Future energy systems will grow smarter and more intricate, and the preparation of strategies for generating electricity for future intelligent power-generating systems will be more challenging to achieve using standard electricity mix optimization techniques. 69An integrated approach is provided here to examine optimum pathways in order to take the first step towards solving the challenge.The integrated model consists of the following components: (i) To design the best power, a multicriteria optimal model is applied.(ii) The reliability of the generation capacity mix to meet electricity demand within specified constraints is evaluated using an hourly simulation model that aims to achieve a real-time demand-supply balance.The optimal power-generating mix was obtained, and extensive information was provided. 70he model's goal is to discover the best power-generating mix possible.If the optimal generating mix combination found in the first stage fails to pass the hourly demand-supply balance simulation, the simulation model will change the mix until a balance is achieved.In detail, as feedback, 1 GW of natural gas power will be raised as a peak power supply to satisfy the supply-demand balance, and then gaseous power will be enhanced by 1 GW in the optimization model based on the original optimized result.The proposed integrated model can be used to come up with solutions for organizing power production that are both cost-effective and good for the environment.This will help us move forward into smart-power electric utilities with a lot of sporadic sustainable energy and loads that can be controlled and managed by smart control strategies.Finally, this may enable the development of realistic power-generating mixes for future smart electrical systems. 71i) Future power generation sources: In the future, power may be generated through various renewable sources, such as the following: • Bioenergy: Bioenergy could be called smart renewable energy in the sense of renewable energy community. 72It is derived from crops like products and also waste in the surrounding environment. 73It should have the potential to generate electricity in grid networks as well as integrate with the smart grid.
• Geothermal energy: Geothermal energy is defined as energy that is obtained through biological cycles from the earth's core. 74This energy is sustainable and reliable in the energy market.It originates from heat produced during the global initial formation and the decomposition of elements.In the earth's core, stones and fluid absorb this thermal energy.This smart renewable has dealt with the energy security of grid networks.
• Speed breaker: Speed breakers could be a source of renewable energy.It drives the mechanical load to power energy, which is part of generating electricity in the smart grid.The speed breaker is typically equipped with a spring or roller system to remove these mechanical energies as a vehicle passes over it.Rotational motions only operate the DC generator and generate electricity. 75Human motion: Human motion-simply walking and jumping-can be sources of smart energy.Various systems of electromechanical mechanisms can be used to recover this energy and transform it into electric energy.The application of a walking load on top of piezoelectric material is another method of using walking to generate electricity. 75iezoelectric materials work through the application of pressure to their surface, and typically, the polarization of these materials changes as the applied load changes.This procedure for generating electricity in grid networks has the potential to integrate with the smart grid.
• Bio-battery: A bio-battery is a type of energy storage technology that works by converting organic chemicals into electricity.Glucose from human blood, for example, is a typical sort of organic chemical that might be utilized to power electrical devices.Enzymes in the human body normally break down glucose, which is subsequently converted into electrons and protons.With the help of enzymes that are synthesized to make glucose, which is directly used in bio-batteries to generate power. 76

Smart energy management
In the modernized world, the demand for power energy from the power system community is increasing day by day.But this demand for power and energy is not constant all day.The increasing demand for electrical energy produces a mismatch between supply and demand that is accountable for power system losses that may involve.In this perspective, power energy needs to be stored for a certain time so that it can be supplied to generation instantly.So power energy, which is from renewable energy, is integrated into the smart grid and has the capability to store devices in batteries, supercapacitors, and flywheels.Energy management in a smart grid network, concerned with the energy demand response to the grid by the consumer, has features with energy monitoring and environmental aspects. 77In advancement technological aspects, smart metering structure, self-healing-based grid, cyber security, and IoT-based monitoring of energy could be given the realistic figures of smart grid energy management. 78

Smart communication
A smart grid is a communication-based approach to grid networking that has two ways of communication interfacing: from the grid to the consumer and from the grid to the grid.The power system community has to demand quality control and monitoring of power energy in smart grid networks in comparison to existing networks.From this grid perspective, ICT-based grid infrastructure is emerging in modern power systems.It could be communicated with consumers, which provides grid system flexibility and resilience in the generation and distribution of the network.To focus on modernization, IoT-based, 5G wireless communication, vpp, ZigBee, and WiMAX are the crucial mediums of communication in the grid system, which collects organized information, stores and sends it continuously to the electrical network. 79his communication system provides real-time grid networks to enhance grid control, grid resilience, operating modes of communication, and remotely controlled smart grid. 9Some technological features of the smart grid system are shown in Table 3.

Virtual power plant
After a protracted period of growth, the virtual power plant has accomplished milestones in the power sector. 81This innovative network provides access to the newest intelligent power system trademark, the virtual power plant (VPP), which incorporates and autonomously organizes a variety of distributed energy resources, power storage infrastructure, and loads, represents and regulates the power generation activities, and contracts intelligently on the electricity market that monitors the flux within the aggregation. 82Figure 4 shows a broad overview of the virtual power plant.VPPs offer significant benefits over traditional power plants in terms of effective transmission infrastructure, adaptable physical traits, and strict regulatory designs.They are by nature collections of energy storage services, controlled loads, and distributed  generation resources (DER) linked to a centralized body. 83The rising demand for sustainable energy consumption and checking has greatly sparked remarkable research on VPPs from a variety of angles.Utilities have frequently used VPPs, virtual power plant aggregators, and the ICT sector in recent years as a result of the certainty of significant gains in power system constancy and flexibility, particularly in reducing the requirement for additional peak-period energy generation. 84

Components of VPP
(i) Distributed energy resource unit: DERs are power production units that use a variety of energy sources in varying amounts to provide users with a more affordable, highly dependable, and efficient energy supply.DERs are classified in various ways.Depending, for example, on energy sources, which are typically classified as renewable or nonrenewable, Renewable energy sources such as solar thermal systems, wind turbines, hydroelectric generators, tidal and geothermal facilities, and photovoltaic arrays are reliable.Moreover, nonrenewable energy sources include nuclear power plants, biomass, gas turbines, and fuel cell manufacturing facilities.But DERs also include CHP facilities, smart grids, and microgrids. 85The crucial benefit of DERs is that they offer load support during peak hours or consistent power delivery during a power outage.Because storage devices charge during off-peak hours and discharge during peak hours, the load assistance during peak periods aids in lowering power prices.
(ii) Energy storage unit: When the demand is at its greatest, ESSs efficiently disperse the energy they have produced during off-peak periods.ESSs exist throughout a sizable fraction and play a crucial function as virtual power plants amalgamate a wide variety of players in a vast geographical region.For example, for both micro and macro applications, they maintain frequency and voltage levels in DERs coupled to VPPs at the root stage.They can have a centralized or decentralized infrastructure, and their goal is to provide municipalities with enough power support while aiming to increase the robustness, safety, and effectiveness of associated systems. 86Several dispersed ESSs work well during widespread power grid disruptions, much like a central power supply.The whole structure is therefore provided with a remarkable level of power within minutes to hours, if necessary.
(iii) Flexible loads: Flexible loads are defined as those that are able to modify their general consumption habits regarding changes in the price of energy or incentive wages.There are two components to so-called responsive or flexible loads.A structure that serves as a conduit for information between the load and the center portion makes up the first component.The second component is the control system necessary to govern the amount of flexible load used. 88In a VPP, the usage level of flexible loads may be altered to satisfy specific requirements.These changes can be made using a valid control command or the dynamic pricing approach price signal class.A comparison is deployed among microgrids, smart grids, and virtual power plants, as shown in Table 4.

EXISTING POWER GRID TRANSFORMER: FUNDAMENTALS AND FRAMEWORK
Technological advancement has been growing in electrical grid networks, now the modern power system deals with the continuity of the power energy distribution in the transmission lines.The electrical power grid has become more complicated over time as more clean and sustainable energy and distributed generation (DG) has been used.It now needs two-way current in the distribution network, as well as decentralized supervision, monitoring, and self-healing. 89In this scenario, SST has made a significant contribution to upgrading the distribution's overall system performance and resiliency.To better enable the combination of decentralized resources and sustainable energy, the solid-state transformer (SST) is suggested to replace the distribution power grid's existing 100-year-old 60 Hz transformers. 90An MV stage, a dc stage, and an LV stage make up the solid-state transformer (SST).It uses medium-frequency (MF) transformers to produce galvanic isolation.SST offers a wide range of sophisticated control capabilities, including input power control/VAR injection, voltage stability, power transfer control, reduced voltage ride-through, islanding operational reliability, current limiting, network impedance mismatch, and energy management systems. 91SST also offers auxiliary services that help to enhance and simplify the contacts of direct current (DC) and alternating current (AC) equipment.So the primary concept of SST is to perform voltage transformation by separating medium-to high-frequency signals, thereby potentially reducing weight and bulk.Some application and communication-based mechanisms of transformers in a power grid system are shown in Table 5.

Functionality of solid-state transformer
An SST's basic functioning can be described as an isolated AC-AC PEC.Various topologies are invited to be candidates for creating SST.In addition, the separated AC-AC PEC depiction of an SST allows for modular assembly, which has emerged as a crucial feature of the design of many modern PECs. 93Despite the enormous number of topologies proposed, four SST topologies have demonstrated promising performance in a variety of applications.Here are the four SST topologies: (i) Passive DC-link, unidirectional; (ii) With a passive DC-link, it is bidirectional; (iii) Active DC-link, unidirectional; (iv) Active DC-link, bi-directional.Several SST topologies, such as AC-DC, DC-link, and DC-AC phases, all make use of PECs as fundamental building blocks. 94PEC parts, such as high-frequency transformers, drive circuits, switching elements, and storing elements, have a finite lifespan.Switching elements, storage elements, drive circuits, and high-frequency transformers are examples of PEC components. 95These components have limited voltage and current ratings that cannot go over SST design specifications.PEC modules connected in series or parallel might be used to solve this issue.Figure 5 represents the infrastructure of the solid-state transformer.

Design and structure
The idea of solid-state transformers has generated considerable interest as prospective transformers in smart grid applications.Solid-state transformers outperform traditional transformers in terms of performance, offering a number of additional services based on power electronics converters.The galvanic isolation between the transformer's LV and HV sides is a key feature.An SST employs high-frequency ac (HFAC) (usually 10-20 kHz) to reduce the transformer size while maintaining isolation between primary and secondary. 96Two main components make up solid-state transformers: a converter to create high-frequency AC from input line-frequency AC and an HFT for high-frequency isolation.On LV and HV side converters, especially on the HV side, the sustained voltage of power semiconductor devices must be very high. 97For the construction of the converters employed in the SST framework, this might be a significant difficulty.

Winding and core design
Regarding power density and efficiency, it is crucial to consider the winding pattern and type of core while designing a transformer.Due to its greater surface area exposed to the environment, the core-type transformer offers stronger insulation and cooling mechanisms, which is suited for HFT design.However, because the SST was created using HFT, it is important to take the high-frequency effect into account. 98High frequency caused primarily two effects-skin effects and proximity effects-to take place.Typically, the conductor's DC resistance is used to calculate the winding losses.The phenomenon known as the skin effect occurs when an AC circulates inside a conductor so that the current density is the greatest close to the conductor's surface and significantly decreases as depth increases. 99As a result, the conductor's real area shrinks, eventually leading to an increase in AC resistance.On the other hand, AC resistance also rises as a result of the magnetic fields produced by neighboring conductors.The current in each conductor concentrates in a smaller region as a result.This occurrence is referred to as the proximity effect. 100

Materials
Regarding leakage current, size, thermal, and many more characteristics of the switch's material are crucial aspects of the switch's design.It has been demonstrated that SiC is superior to Si for high-power and high-frequency applications.Additionally, SiC material offers far higher efficiency than Si, and devices with high power density can switch at higher levels of voltage, current, and frequency.These compounds have only so far been used to increase SST effectiveness.SiC-based MOSFET and IGBT devices have been proposed and investigated.IGBT, IGCT, ETO thyristor, and power MOSFETs are suited for powering high-voltage semiconductor devices. 102Very high voltages may be tolerated by these switches.High-voltage applications may also be solved by arranging a number of low-voltage power semiconductor devices.The use of embedded systems in a series connection of power switches can significantly mitigate this shortcoming and also provide the capability to operate at high frequencies for the series configuration.The solid-state transformer's primary side semiconductor switches must be made to function at 15 kV. 102MOSFET and IGBT are frequently utilized in electrical circuits as switching devices.The characteristics of MOSFETs include high input impedance, quick switching, outstanding thermal stability, voltage control current, and others.IGBTs have high input impedance, low power requirements for controlling voltage, a straightforward control circuit, strong voltage resistance, and high current tolerance. 103

Topologies
SSTs are divided into the following categories, types, and power levels: In terms of the number of levels, the categorization is as follows: (i) Single step: It has been without a constant DC connection.Though it offers a cost-effective design and the renewable energy portion is supported by galvanic insulation, there are some significant losses and massive current ripples.(ii) Double step: It could be categorized into two parts: one includes the HVDC connection, while the other includes the low-voltage alternating current (LVAC) connection.It has possibilities for power transmission between RES and DES.However, it may have been difficult to connect with FACTS in the high-voltage environment. 104(iii) Three steps: Finally, this network has been unveiled, with both LVDC and HVDC cables being added to keep the system stable and ripple-free and also support the RES and DERs.
Another possible categorization may involve points of type: (iv) Type A: it is simple in construction and has power conversion capability with an MFT (medium frequency transformer).It has an obstacle to monitoring the closed-loop operation and the loss of zero voltage switching.(v) Type B: It consists of an AC-DC conversion stage with a low-voltage DC output, then a DC-AC conversion with a low-voltage AC output.(vi) Type C: The LVDC link is a variant of Type B, in which the two stages support galvanic isolation and voltage stepping down.(vii) Type D: It consists of a three-stage conversion procedure with one MFT isolation and two DC connectivity links (MVDV and LVDC).(viii) Type E: This system is based on zero-voltage switching (ZVS) modulation, which has proven to be extremely efficient. 105

Controlling operation
Controlling SST could be a top priority for a grid network.One of the controlling operations could be multiobjective modulated predictive control.It fixes the issues with the traditional predictive control method of creating voltage harmonic spectra and functioning at very high frequencies while focusing on speeding up the system's response time.The phase shift control approach is additional.This technique involves applying a phase shift between the high-frequency transformer's primary and secondary voltages (HFT).It could have features to regulate the system's power flow's intensity and direction. 106Another way to minimize voltage fluctuations and their transient duration is the feed-forward control method.To account for inductor energy variations, a feed-forward control scheme is suggested.A second feed-forward control strategy is suggested to regulate the voltage of the rectifier controller section.Both control loops improve the dynamic voltage conditions of the system's DC voltage.

CRITICAL REQUISITES FOR NEXT-GENERATION POWER GRID TRANSFORMER
The nation's electricity system is undergoing an upheaval.The system becomes more complex as a result of the integration of a massive amount of renewable sources and new demand loads, which has occurred alongside a tremendous increase in installed generation capacity recently.Additionally, the grid must manage power flows in many directions, round-the-clock, due to the presence of numerous generators, prosumers, and decentralized generation sources. 107nergy utilities are addressing these issues by using digital technologies, with the goal of assisting users in obtaining information and insights that can be used to make better decisions and manage assets.
• Transformers currently serve as the hub of electrical networks and are anticipated to take on a considerably larger role in the future power grid as it expands; they are the prime candidates for the integration of digital and smart grid technology. 108 • The modern electrical grid is increasingly dependent on digital transformers, which autonomously control voltage and stay in touch with the smart grid to enable remote administration and real-time feedback on power supply characteristics. 109 • In terms of distribution and transmission, the utilization of these transformers is expanding.Intelligent electronic components, as well as sophisticated monitoring and diagnostic functions, are included in these transformers. 110Transformers, which perform the crucial task of adjusting voltage levels, stepping up for effective long-distance high-voltage transmission, and stepping down for the distribution of power to consumers, have undergone a lot of technological advancements over the generations.These include high-efficiency distribution transformers, biodegradable oil-filled transformers, ultra-low-sounding transformers, and ultra-high-voltage AC and DC technology.
• The major goals for many utilities, however, continue to be enhancing monitoring and maximizing maintenance.For instance, load peaks, both expected and unanticipated, cause high temperatures that reduce transformer life.
• There are times when unexpected failures can happen, disrupting the network and resulting in fines and other consequences.Additionally, a sizable number of small, local energy producers run renewable power plants that alter the flow of electricity in the distribution network at the consumer end of the grid.The next-generation transformers are gaining ground as a solution to the new and upcoming grid concerns. 111The three main components of digital transformer solutions are hardware, software, and services that work together seamlessly to manage the flow effectively, consistently, and safely.
• To provide utilities with dependability, efficiency, and future readiness, hardware, software, and services must seamlessly integrate.To collect data for local monitoring, diagnostics, and control, built-in components such as digital sensors, dissolved gas analyzers, and digital safety devices are used.Through the use of the cloud, the same data may also be tracked and used for station control, as well as for preventative and predictive maintenance.

Interoperability
The capacity of two or more software components to work together despite variations in language, interface and execution platform is known as interoperability.Being concerned with the reuse of server resources by clients whose accessing techniques may be plug-in compatible with the server's sockets, it is a scalable kind of reusability.When it comes to plugging compatibility, electrical equipment demands both static form compatibility and dynamic voltage and frequency compatibility. 112Compatibility and interoperability have certain similarities.While giving them a more comprehensive perspective of all their information, it helps organizations operate more effectively and efficiently.

Authenticity
Transformers with digital capabilities can perform real-time data analytics and remote monitoring of their critical parameters.So, grid assets and power networks can be used more effectively, increasing reliability.Additionally, these transformers have a digital hub that can connect to a variety of smart devices on a modular platform with plug-and-play capabilities.Digital capability can increase reliability and reduce outages through proactive measures, in addition to enhancing efficiency and product life.The digital transformer serves as a voltage regulator by supplying the exact amount of power needed and reacting quickly to power grid variations.They are the best choice for power systems that are intended to integrate renewable energy sources, thanks to their capabilities.In the meantime, digital distribution transformers at the transformer level offer intelligence to maximize dependability, save operational and maintenance expenses, and manage the asset more effectively.Technology companies are aiming to build sensor technology right into the transformer during production, which would increase accuracy.Providers of technology are also incorporating digital technologies into dry-type transformers.Transformers of the dry-type variety are designed to operate without the use of oil, instead relying on air and noncombustible solid insulating material to keep the core and coil at a safe operating temperature, as opposed to how transformers are typically cooled and insulated by oil.They become safer and more environmentally friendly as a result.These transformers are best used in high-risk situations, such as offshore, densely populated areas, and delicate ecosystems.Smart sensors collect data and combine it to produce powerful analytics in digitally enabled dry-type transformers. 113

Cyber security
Along with the numerous technical features listed, new digital transformers also address clients' cybersecurity concerns.This is accomplished by including extra security measures, like Wi-Fi that is equipped with RFID access cards.A decryption key is required for the user to read the encrypted data because it is stored in a secure manner. 114

Failure mechanism analysis
Failure mechanisms are the rules that can be found by studying or testing the connections between fault features and measurements of the transformer's state.A worldwide survey of component-wise failures of transformers is shown in Table 6.Transformer condition evaluation presents difficult problems, such as how to effectively extract important elements of the transformer operating state and perceive the correlation of complicated transformer failures using machine learning in combination with the current under-fault method. 115

Data quality
Data on power grid transformers, including operational capacity, oil tests, live-line detection, online monitoring, maintenance records, and fault issues, has been collected thus far by academic institutions, power utilities, and manufacturers thus far.However, the transformer state data is heterogeneous, has uneven data quality, and is asynchronous since it is stored in separate, unrelated sub-systems.Because of measurement inaccuracies, duplicate data, and data absence, assessing a transformer's condition is erroneous.When data quality is low, diagnostic and predictive results for transformer problems will not accurately reflect reality.Therefore, improving transformer data quality is essential. 116

ROAD TO NEXT-GENERATION POWER GRID TRANSFORMER
In the past ten years, numerous energy sectors, research centers, equipment-operating companies, and manufacturers have worked to develop cutting-edge technologies that are frequently used in power grids, such as big data, cloud computing, the Internet of Things, mobile internet, and artificial intelligence.These innovative technologies can facilitate the mining of rules from climate data, electric grid operational data, and transformer operating information.The use of advanced measurement infrastructures in smart grids and the gradual rise of large amounts of different types of rapidly growing transformer state data have both made operation and maintenance of power grid transformers easier.This has made it possible to use big data, AI, and other technologies. 117IoT technology is currently achieving vital appeal in the power sector.In 2023-2025, it is anticipated that 20-50 billion items will be globally connected to the internet. 118In addition, a significant number of highly accurate smart sensors have been researched, produced, and used, offering a more extensive data foundation for big data analysis.The progress of power grid transformers is moving in the fields of high voltage, huge capacity, intelligence, dependability, and energy efficiency.
A visual representation of the applications of next-generation power grid transformers and it is framework is shown in Figure 6.The capabilities of the upcoming power grid transformer include the following: (i) Self-protection by separating the complete maintenance crew in the event of a transformer overload.(ii) No wires are required.Preventing power or data loss as a result.(iii) Real-time defect detection using current, voltage, and temperature.(iv) Remotely monitoring several transformers. 119 By monitoring the system, you can increase stability and dependability. 120(vii) This method prevents excessive current and temperature.A structural comparison of the existing power grid transformer and the next-generation power grid transformer is shown in Table 7.

Add on components
In the present transformer sector, intelligent transformers with self-diagnosis capabilities are a massive issue.The use of intelligent sensors and actuators, clear channels of communication, efficient management of operational data accurate diagnosis and evaluation of operating conditions, close monitoring of operational data and fault alert functionality may all be features of intelligent transformers that set them apart from conventional transformers. 121Further implementation should focus on this type of smart transformer that can withstand the widespread use of intermittent new energy sources and applications (such as solar power production and electric automobiles). 122Figure 7 depicts the technology that may be used to digitalize the transformer.This digitalization of transformers is completely automated and allows only authorized workers to secure, monitor, and operate related equipment from anywhere on the globe.F I G U R E 7 Digitalization of transformer.

Intelligent condition monitoring
Condition evaluation for power grid transformers primarily evaluates and assesses the health condition using a small number of state characteristics and uniform diagnostic criteria, which fails to fully take advantage of faults. 123The transformer's current monitoring system is not fully automated.Currently, a technician must read data from the transformer panel, which might result in reading errors, inaccuracies, and a long wait before receiving the reading value for the winding temperature, oil level, and top oil temperature.In order to visualize and enhance the current framework for transformer state evaluation, it is crucial to use innovative methodologies. 124The acquired transformer data has big data traits due to the advancement of online monitoring tools, cyber-physical systems, and the Internet of Things. 125The primary goal of real-time condition monitoring for the power grid transformer is to alert users to any potential abnormal events. 126lacing the sensors on the asset and connecting them to a microprocessor board with the appropriate programming will enable real-time monitoring.This data may then be transferred to a server or cloud for data analysis and real-time monitoring.The following are the primary benefits of adopting IoT for real-time monitoring: minimizing the usage of hardware for data transmission from the sensors to the monitoring system; the server or cloud may be accessed from several locations, not only one monitoring center. 127Since there are many suppliers of sensors, numerous manufacturers of microprocessor boards (including Arduino, Raspberry Pi, Intel, and Beaglebone), and numerous competitors offer cloud services with various options for transformer condition management and analysis.

Intelligent command
Approaches to the intelligence controlling method, operating the existing transformer in future-oriented is, however, AI-based field operation, which could be optimization operators, artificial neural networks, digital logic, machine learning, recurrent neural networks, and evolutionary computation.That means it provides the database-analyze operation, decentralized monitoring, and network sustenance of the transformer.It would be a meaningful continuity of energy distribution in transmission lines, observing enhancement and reliability. 128

Edge computing
By 2025, the amount of data on the globe is projected to increase by 61% to 175 zettabytes.Data centers cannot ensure adequate transfer speeds and reaction times despite advancements in network technology, despite the fact that these factors are frequently a crucial need for many applications.A distributed computing system called edge computing puts all applications closer to data sources like IoT gadgets or regional cloud servers, where data is processed and analyzed closer to the source of creation.Since no data needs to be sent to a cloud or data center for processing, latency is drastically reduced. 129The immediate data that edge computing uses is real-time data produced by sensors or users.With the help of edge computing, particularly mobile edge computing on 5G networks, it is possible to analyze data more quickly and thoroughly, leading to deeper insights, quicker responses, and better consumer experiences. 130The existing transformer has a deficiency with respect to data security and data storage in the central data center.To optimize in this aspect, edge devices in the transformer will be able to make connections and transmit data to the regional network and the data center.
Figure 8 shows the smart edge computing platforms that illustrate the technologies needed to make IoT devices.It resembles an intelligent gateway-it interprets, classifies, and cryptographically transmits data between multiple origins. 131I G U R E 8 Generic IOT devices functionality.
They are the pioneers in monitoring and analyzing data to quickly recognize discrepancies in order to avoid severe failures in transformers.

Intelligent inverters
To be intelligent, a power electronics inverter system needs a digital design, reliable software, and two-way communication capabilities.In order to promote human comfort using Wi-Fi technology and participate in two-way communication with the user, an eco-friendly IoT-based smart-controlled inverter is suggested.Through a mobile application or web URL, the user may manage the linked load and keep track of the status and current load of the connected devices.Where the user may connect or disconnect the gadgets in accordance with their preferences or needs.A current sensor measures the load current, and a Wi-Fi module transmits the data it has collected to a Web URL. 132The implementation method was organized in order to design a transformer that supports the grid in contending with sporadic generation through intelligent inverters.As more dispersed sources of energy go digital, intelligent inverters are getting more involved in decisions to ensure the transformer's stability and dependability, integrating with the smart grid.This could have autonomous decisions in the case of "out of tolerance" voltage or frequency; intelligent inverters will "randomize" the time they spend disconnected from the grid. 133

Smart materials
Developing criteria for next-generation transformers should be focused on their electrical conductivity, thermal conductivity, passive power conversion, and thermal management system performance characterization.Diamond-based semiconductor materials, however, are suitable and offer high breakdown voltage capabilities to switch at high frequencies as well as the best thermal conductivity.Nanocomposite soft magnetic materials are another innovative material for intelligent transformers, offering disruptiveness in passive power conversion and utilizing high frequencies to offer low-loss operation. 134Self-healing ceramics and polymers have potential in the field of electrical insulation and provide high thermal conductivity and capabilities for quickly recovering.Super-hydrophobic materials used for conductors and insulators provide enhanced reliability.Metal hydride alloys could be used as a material to help regulate the thermal energy in transformers.Comparing metal hydride alloys to conventional transformer materials, they show improved heat dissipation.carbon nanotubes and graphene.Carbon nanotube-based conductors might have the same operating performance as materials that are superconducting at room temperature because of the material's ballistic conductivity. 135

Intelligent management
In the process of distributing power, power transformers, one of the network's essential components, may act as strategic bottlenecks.In aspects of the electrical environment, these transformers are needed to be the managerial point of view; better tools are required to allow for management based on facts rather than presumption.Constantly and effectively keeping track of the load, operating conditions, and transformer condition while having control over cooling systems and online tap changers needed to be focused.Transformer utility environment cost and competitiveness are effectively reduced and enhanced customer service and reliability. 136The significance of dynamic rating as a transformer management feature is frequently cited.Based on real-time measured ambient and transformer temperatures, conditions, cooling state, and load, the dynamic rating of a transformer is the highest load that may be applied without exceeding predefined thermal and current rating limits.Advanced transformer management systems use upgraded thermal models, which are inherently more accurate, in addition to real-time observations and calculations for dynamic rating. 137An advanced TMS should incorporate smart cooling functionality that, upon detecting a rapid rise in load, predicts what the final winding temperature will be and promptly activates cooling fans and pumps to cool the transformer without waiting for the temperature to drop to the desired level.The transformer management system acts as a lone point of contact with the outside world, substantially streamlining communications and making it easier to access data about every aspect of the transformer's functioning and status.SCADA, LAN/WAN, a modem, and the internet gather a wide range of data, such as operating information in real-time, condition status, maintenance warnings, and asset life consumption.A conceptual frame of evolution of the existing power grid transformer to the next-generation power grid transformer by adding some featuring components is represented in Figure 9.
F I G U R E 9 Evolution of existing power grid transformer to the next-generation power grid transformer.

Future trends of next-generation power grid transformer
Investments in power transmission and distribution infrastructure and grid assets, including transformers, will increase as global renewable energy production continues to scale up.Despite a mature industry, a substantial increase in electrical consumption, growing electrification rates, economic expansion, and rising population throughout China, India, Asia, the Middle East, and Africa will drive up demand for both power and distribution transformers. 138The modern energy grid, which autonomously controls the voltage and keeps in touch with the smart grid, enables remote technology.
Administration and real-time feedback on power supply characteristics are increasingly reliant on digital transformers.Since smart transformers are created with contemporary uses in mind, many of them will feature brand-new materials, design strategies, and internal technology.The generation of conceptual ideas for future power grid transformers is shown in Figure 10.This opens up a wide range of new possibilities, some of which will not be recognized until smart transformers are operational.Transformers now serve as the hub of electrical networks and are anticipated to take on a considerably larger role in the future power grid as it expands; they are the prime candidates for the integration of digital and smart grids. 139At the distribution and transmission levels, the utilization of these transformers is expanding.These transformers have sophisticated monitoring and diagnostic tools as well as clever electrical gadgets. 140Significant prospects are brought about by the use of active equipment in smart grids, such as smart transformers, which are driven by intelligent software and networking capabilities.Here are some probable future scenarios regarding intelligent transformers: • The purpose of the future power grid transformer is to deliver dependable and high-quality electricity in an affordable and environmentally friendly way, where distributed generation (DGs) are strongly integrated and self-healing is necessary. 141A novel approach to power system protection is required given this view of the power grid of the future.The future smart grid's dynamic nature will create this requirement, which is why several protection systems and procedures have been studied and tested over the years.By leveraging its own cyber-physical resources, like intelligent transformers, the smart grid is able to avoid or mitigate failures, even cascading ones, in an online and automated manner.When a disruptive event, such as a line failure, happens, it combines three capabilities: (i) load shedding; F I G U R E 10 A conceptual idea for future power grid transformer.
(ii) generation management; and (iii) optimizing flow distribution through smart transformer coordination.Smart transformers are assessed in three healing modes in which they function at various phases of cascade failure.
• Transformers with digital capabilities will allow for real-time remote monitoring and data analysis of their critical parameters.This raises dependability and permits greater use of grid resources and power networks.Such transformers also have a digital hub with plug-and-play capabilities that can access a variety of smart devices on a modular platform.Digital capabilities may increase dependability and prevent outages, in addition to extending product life and efficiency. 142 • As a voltage regulator, a digital transformer delivers the exact amount of power needed and reacts quickly to power grid variations.Digital transformers are the best choice for electrical systems intended for the accumulation of sustainable energy because of these characteristics.Digital distribution transformers, on the other hand, offer intelligence at the level of the distribution transformer, maximizing dependability, optimizing operations and maintenance costs, and managing the asset more effectively.In order to increase accuracy, technology vendors are attempting to integrate sensor technologies directly into the transformer during the production process.It will bring tremendous change to the field of digitalizing transformers.
In 2023, the worldwide smart transformer market will be worth USD 1.93 billion.The market is expected to increase at a CAGR of 13.6% between 2022 and 2029, from USD 2.14 billion in 2022 to USD 5.22 billion in 2029.Figure 11 sums up the global transformer market as it is rising.
• Energy consumption will be directly decreased with smart transformers.As a result, it will also directly lower greenhouse gas emissions.They are therefore a crucial component of any energy or lighting upgrade. 143Smart transformers not only safeguard electrical equipment from power fluctuations, which helps electrical equipment survive longer, but they also immediately cut power usage by offering a consistent, perfect power supply that feeds electrical equipment with its ideal voltage. 144They can also be managed dynamically through their connectivity to the smart grid, enabling facilities to monitor and control the transformers directly during times of power fluctuation and assisting them in making sure that their power supply maintains voltage optimization even when new demands are placed upon it.
• When a traditional transformer starts to fail, someone has to physically travel to its location to confirm its status and fix any issues.Smart transformers, on the other hand, include solutions to verify conditions and information remotely, from either a central office or mobile command station.This support vastly improves operations and helps power companies better manage networks.• These transformers are easier to inspect, safer to use, and more dependable as a result of their connection with a smart grid and improved remote monitoring.
• Smart transformers are made to use power more efficiently and distribute it throughout the grid.This results in more efficient electricity utilization and lower emissions of greenhouse gases.Conventional power plants use less fossil fuel as a result of a more effective grid, which also reduces emissions and improves urban air quality.
• When a transformer breaks, electricity is lost, often for days at a time, and many homes and businesses are left without power.Intelligent transformers can take over operations, direct power more effectively to avoid this, and make up for it.Communication technology, characteristics, and application of next-generation transformers are shown in Table 8.

6
CHALLENGES FOR NEXT-GENERATION POWER GRID TRANSFORMER

Data handling and processing
The digitalization of the transformer consists of a wide variety of things: internet-connected, cloud-based, and edge-based computers.A system that can identify and tolerate faults in these devices is necessary for their administration.Therefore, it is crucial to have a requirement that appropriately controls the transformer's interface with these devices, their setup, and the accessibility of various user levels. 150Next-generation transformer power systems need effective data handling and processing due to the increased data volume.Large amounts of data can put a burden on storage, processing, and analytical capacities.Data is available in a variety of formats, including structured, semistructured, and unstructured data.Managing and integrating many data kinds can be difficult.To handle huge data efficiently, specialized tools and technologies are frequently necessary.Therefore, processing in the near future will require the use of cutting-edge technologies and equipment.Because nodes can see the status of the central server or their neighbors, they may save more data transfer.However, because of the most virtual nature of its processing, it is desirable to be able to cope with massive volumes of large data. 1511.2Data privacy, security, and management The concepts of security and privacy are inextricably linked.If the degree of security is inadequate, the grid transformer will be subject to unauthorized manipulation, compromising its privacy.It is very difficult to provide a high degree of privacy and security due to a lack of universal standards, such as cyber protection.Data gathering and analysis are critical components of a grid transformer.This data is generally obtained online and maintained at regular intervals.After assessing the acquired data, judgements are made on the most effective grid distribution activities. 152Although a sophisticated data management system may be utilized to assess transformer grid performance, the existence of a data security standard is still required.In addition, the most important security needs are information integrity, mutual trust, and authentication.Apart from security, privacy is critical for maintaining consumer's faith in PGT.To secure information, the use of smart devices with personal and sensitive information necessitates strict privacy measures.we can reduce this problem using strong authentication measures like multi-factor authentication (MFA) and reviewing user access permissions based on job positions and responsibilities on a regular basis. 153

Energy management point of view
Energy management in power transformers requires a holistic approach that combines modern technologies, real-time monitoring, and proactive maintenance procedures.This not only improves energy efficiency but also the dependability and longevity of power transformers within the larger energy infrastructure.The proper usage of grid power largely depends on the accurate regulation of the energy management system of the transformer.It is directly connected with both transmission and distribution through continuous reporting of different information such as energy usage, power consumption, cost and availability of energy, market demand, and so on.It manages the production of power based on the demand forecast for energy and follows power according to customer need. 154

Economical point of view
There are many expenses connected with the energy consumption of integrated PGT for grid renewables.These costs consist of gadgets, operational expenses, fees for technical services, and maintenance expenses.Moreover, when diverse renewable energy sources are connected to the grid, there is also an integration cost.On one end, the high cost of an EMS directly affects the grid transformer.Alternatively, the performance of the transmission and distribution transformers in the power system might be compromised by the use of less expensive materials. 155Power transformer economic cost reduction requires a combination of strategic planning, effective operation, and wise investment selections.

Operational point of view
The next-generation transformer has the ability to run all of its functions autonomously with little human involvement with the aid of several sensors, actuators, and controls.The important key characteristics connected with the digitalized transformer are automatic maintenance and reconfiguration based on the situation, adaptive protection and management, advanced forecasting, and demand support. 156The changeable character of the generation units and the load or the affection of the fault or uncertainties in the electrical system may damage the nominal functions of the transformer, which may result from large deviations of the voltage, current, or frequency.It is dynamically challenging for an automated transformer to restore and optimize the operations of its components in an emergency.Adaptive protection and management are also the challenges of PGT for the grid system based on the situation or environment shift by adjusting its settings to match the new state. 157Self-healing and optimization are the processes used to optimize the operations of the PGT in cases of faults, uncertainties, and load variations.Investigating self-healing grid technologies allow transformers and other components to divert power or isolate problematic areas autonomously, decreasing the impact of outages.

CONCLUSION
The modern power energy infrastructure has developed noticeably in the field of power transmission distribution and management, integrating with the digitalization of transformers.The next-generation transformer probably combines many sophisticated components, resulting in reliable operation in the transmission lines.In essence, this means that power systems have fully accepted digital technologies.This digitalization has resulted in better capacities, efficiency, and more sophisticated control over the entire energy distribution network.It incorporates consistent information security solutions, edge computing, cloud-based monitoring, and other technical services.Within the scope of this study, efforts have been made to evaluate current transformer technologies, serving as a foundation for envisaging future developments in the field.Some future systematic devices that are about to be adopted are also described using the existing components.
There is also a brief explanation of the critical requisites for renewable power grid transformer implementation.In conclusion, The establishment of a next-generation power grid transformer demands concerted research and development efforts that capitalize on the capabilities of advanced transformer technology.

F I G U R E 4
Overview of virtual power plant.
(v) The usage of Wi-Fi results in improved fault monitoring accuracy and reaction times.(vi) F I G U R E 6 Application-based next-generation power grid transformer.
48n countries almost generate 100 % renewable-based electricity.48 TA B L E 2 80art grid technological category and examples of hardware and software systems.80 TA B L E 3Wide area control and surveillance Phasor management systems and other sensors Systems for widespread monitoring, widespread adaptive defense, supervisory control, and data gathering Smart metering infrastructure Smart meters, servers and relays Data management system 87aracteristics comparison among microgrid, smart grid, and virtual power plant.87 TA B L E 4 92ansformer applications and communication in power grid.92 TA B L E 5 F I G U R E 5Solid-state transformer.
101ponent-wise failure of transformers and reactors-worldwide-survey.101 TA B L E 6 Structural comparison between an existing power transformer and next-generation power transformer.
TA B L E 7 145 Communication technologies used in smart transformer and their applications.
F I G U R E 11 Global smart transformer market rises.TA B L E 8 GPRS(general packet radio service). 146900 MHz & 1800 MHz In packet transmission mode, transmit and receive data Used in transformer monitoring system.(a) It is capable of lowering the cost of replacing a damaged transformer.(b) Improves reliability.