With the development of information networks, the problem of power security has increasingly caused many attention of people, but the simple power security defense system has been difficult to meet the current complex...With the development of information networks, the problem of power security has increasingly caused many attention of people, but the simple power security defense system has been difficult to meet the current complex network environment. Aiming at this situation, by using the method of T-S fuzzy neural network model to analyze the characteristics of the data transmission in network, it has obtained corresponding threat information. By processing these threat information, it completes the construction of three-dimensional power security defense system. The paper carries on the corresponding data training methods by using T-shirt model fuzzy neural network, which has certain reference significance for the data analysis of other similar fields. At the same time, the study of building on the three-dimensional power security defense system aims to provide a theoretical reference for solving the security defense of the current complex network environment.展开更多
False Data Injection Attacks(FDIAs)pose a critical security threat to modern power grids,corrupting state estimation and enabling malicious control actions that can lead to severe consequences,including cascading fail...False Data Injection Attacks(FDIAs)pose a critical security threat to modern power grids,corrupting state estimation and enabling malicious control actions that can lead to severe consequences,including cascading failures,large-scale blackouts,and significant economic losses.While detecting attacks is important,accurately localizing compromised nodes or measurements is even more critical,as it enables timely mitigation,targeted response,and enhanced system resilience beyond what detection alone can offer.Existing research typically models topological features using fixed structures,which can introduce irrelevant information and affect the effectiveness of feature extraction.To address this limitation,this paper proposes an FDIA localization model with adaptive neighborhood selection,which dynamically captures spatial dependencies of the power grid by adjusting node relationships based on data-driven similarities.The improved Transformer is employed to pre-fuse global spatial features of the graph,enriching the feature representation.To improve spatio-temporal correlation extraction for FDIA localization,the proposed model employs dilated causal convolution with a gating mechanism combined with graph convolution to capture and fuse long-range temporal features and adaptive topological features.This fully exploits the temporal dynamics and spatial dependencies inherent in the power grid.Finally,multi-source information is integrated to generate highly robust node embeddings,enhancing FDIA detection and localization.Experiments are conducted on IEEE 14,57,and 118-bus systems,and the results demonstrate that the proposed model substantially improves the accuracy of FDIA localization.Additional experiments are conducted to verify the effectiveness and robustness of the proposed model.展开更多
How to comprehensively consider the power flow constraints and various stability constraints in a series of power system optimization problems without affecting the calculation speed is always a problem.The computatio...How to comprehensively consider the power flow constraints and various stability constraints in a series of power system optimization problems without affecting the calculation speed is always a problem.The computational burden of probabilistic security assessment is even more unimaginable.In order to solve such problems,a security region(SR)methodology is proposed,which is a brand-new methodology developed on the basis of the classical point-wise method.Tianjin University has been studying the SR methodology since the 1980s,and has achieved a series of original breakthroughs that are described in this paper.The integrated SR introduced in this paper is mainly defined in the power injection space,and includes SRs to ensure steady-state security,transient stability,static voltage stability,and smalldisturbance stability.These SRs are uniquely determined for a given network topology(as well as location and clearing process for transient faults)and given system component parameters,and are irrelevant to operation states.This paper presents 11 facts and related remarks to introduce the basic concepts,composition,dynamics nature,and topological and geometric characteristics of SRs.It also provides a practical mathematical description of SR boundaries and fast calculation methods to determine them in a concise and systematic way.Thus,this article provides support for the systematic understanding,future research,and applications of SRs.The most critical finding on the topological and geometric characteristics of SRs is that,within the scope of engineering concern,the practical boundaries of SRs in the power injection space can be approximated by one or a few hyperplanes.Based on this finding,the calculation time for power system probabilistic security assessment(i.e.,risk analysis)and power system optimization with security constraints can be decreased by orders of magnitude.展开更多
Power system security and stability is very important to national economy and people's life,so it has been paid great attention by governments and power utilities.In order to avoid huge economic losses caused by l...Power system security and stability is very important to national economy and people's life,so it has been paid great attention by governments and power utilities.In order to avoid huge economic losses caused by large-scale blackouts,State Grid Corporation of China(SGCC)have invested sufficient human and financial resources to carry out related researches,and remarkable achievements have been achieved.However,large grid stability problem is very complex,it is still difficult to completely avoid the blackouts.展开更多
In this paper,a series of major policy decisions used to improve the power grid reliability,reduce the risk and losses of major power outages,and realize the modernization of 21st century power grid are discussed. The...In this paper,a series of major policy decisions used to improve the power grid reliability,reduce the risk and losses of major power outages,and realize the modernization of 21st century power grid are discussed. These decisions were adopted by American government and would also be helpful for the strategic development of Chinese power grid. It is proposed that China should take precaution,carry out security research on the overall dynamic behaviour characteristics of the UHV grid using the complexity theory,and finally provide safeguard for the Chinese UHV grid. It is also pointed out that,due to the lack of matured approaches to controll a cascading failure,the primary duty of a system operator is to work as a "watchdog" for the grid operation security,eliminate the cumulative effect and reduce the risk and losses of major cascading outages with the help of EMS and WAMS.展开更多
Electricity network is a very complex entity that comprises several components like generators, transmission lines, loads among others. As technologies continue to evolve, the complexity of the electricity network has...Electricity network is a very complex entity that comprises several components like generators, transmission lines, loads among others. As technologies continue to evolve, the complexity of the electricity network has also increased as more devices are being connected to the network. To understand the physical laws governing the operation of the network, techniques such as optimal power flow (OPF), Economic dispatch (ED) and Security constrained optimal power flow (SCOPF) were developed. These techniques have been used extensively in network operation, planning and so on. However, an in-depth presentation showcasing the merits and demerits of these techniques is still lacking in the literature. Hence, this paper intends to fill this gap. In this paper, Economic dispatch, optimal power flow and security-constrained optimal power flow are applied to a 3-bus test system using a linear programming approach. The results of the ED, OPF and SC-OPF are compared and presented.展开更多
After the digital revolution, the power system security becomes an important issue and it urges the power producers to maintain a well secured system in order to supply a quality power to the end users. This paper pre...After the digital revolution, the power system security becomes an important issue and it urges the power producers to maintain a well secured system in order to supply a quality power to the end users. This paper presents an integrated Corrective Security Constrained Optimal Power Flow (CSCOPF) with Flexible Transmission Line Impedance (FTLI) to enhance the power system security. The corrective approach of SCOPF is chosen, because it allows the corrective equipment to bring back the system to a stable operating point and hence, it offers high flexibility and better economics. The concept of FTLI arises from the ability of FACTS devices such as Thyristor Controlled Series Capacitor (TCSC), which can vary the line reactance to a certain extent. An enhanced security can be achieved by incorporating FTLI into the CSCOPF problem, since the power flow in a system is highly dependent on the line reactance. FTLI based CSCOPF can reduce the amount of rescheduling of generators, but it will result in an increased number of variables and thus, the complexity to the optimization process is increased. This highly complex problem is solved by using nonlinear programming. The AC based OPF model is preferred, since the corrective security actions require highly accurate solutions. IEEE 30 bus system is used to test the proposed scheme and the results are compared with the traditional CSCOPF. It can be seen that the proposed idea provides a notable improvement in the reduction of cost incurred for restoring the system security.展开更多
With the increasing penetration of renewable energy in power system,renewable energy power ramp events(REPREs),dominated by wind power and photovoltaic power,pose significant threats to the secure and stable operation...With the increasing penetration of renewable energy in power system,renewable energy power ramp events(REPREs),dominated by wind power and photovoltaic power,pose significant threats to the secure and stable operation of power systems.This paper presents an early warning method for REPREs based on long short-term memory(LSTM)network and fuzzy logic.First,the warning levels of REPREs are defined by assessing the control costs of various power control measures.Then,the next 4-h power support capability of external grid is estimated by a tie line power predictionmodel,which is constructed based on the LSTMnetwork.Finally,considering the risk attitudes of dispatchers,fuzzy rules are employed to address the boundary value attribution of the early warning interval,improving the rationality of power ramp event early warning.Simulation results demonstrate that the proposed method can generate reasonable early warning levels for REPREs,guiding decision-making for control strategy.展开更多
An analysis of the recent major security incidents related to industrial control systems,revealed that most had been caused by company employees.Therefore,enterprise security management systems have been developed to ...An analysis of the recent major security incidents related to industrial control systems,revealed that most had been caused by company employees.Therefore,enterprise security management systems have been developed to focus on companies’personnel.Nonetheless,several hacking incidents,involving major companies and public/financial institutions,were actually attempted by the cooperative firms or the outsourced manpower undertaking maintenance work.Specifically,institutions that operate industrial control systems(ICSs)associated with critical national infrastructures,such as traffic or energy,have contracted several cooperative firms.Nonetheless,ICT’s importance is gradually increasing,due to outsourcing,and is the most vulnerable factor in security.This paper proposes a virtualized security management scheme for the resident cooperative firms in the industrial control infrastructure.Since such companies often cannot afford adequate investment in security,the scheme is to let an ICS company provide the virtualized system.One of its merits is the convenience of controlling a VDI server at the center.The cooperative firms were classified,based on their respective security levels,and statistics were collected throughout a four-year period for the results.This paper analyzes the policies and virtualization systems that have been applied to the security of the partner companies,which engaged in ICS security.A suitable model for ICS security was then proposed by analyzing their effects on the system efficiencies,based on the comparisons of the security inspection results obtained before and after virtualization.The proposed system is expected to contribute to industrial safety.展开更多
Based on the measured data of geomagnetically induced currents （GIC） in Guangdong Ling＇ ao 500 kV power networks during several magnetic storms at the peak years of 23rd Solar Cycle, the GIC calculation results of ...Based on the measured data of geomagnetically induced currents （GIC） in Guangdong Ling＇ ao 500 kV power networks during several magnetic storms at the peak years of 23rd Solar Cycle, the GIC calculation results of 750 kV planning power grid in Shartxi, Gansu, Qinghai and Ningxia, the structure and characteristics of power networks from 500 kV to 1 000 kV, and super magnetic storm in 1859 are analyzed in this paper. Through the analysis, the possible impacts of extreme space weather on the future ultra-high voltage （UHV） grid, the security of large-scale power system in China are expounded, and the research suggestions coping with the strong solar storms are proposed.展开更多
In developing power grids,setting standards is critical to its success.The development of China’s power industry has proposed new requirements for power systems to ensure secure and stable operations.The principal st...In developing power grids,setting standards is critical to its success.The development of China’s power industry has proposed new requirements for power systems to ensure secure and stable operations.The principal standards for the security and stability of China’s current power systems are analyzed in terms of operational control,generator-grid coordination and simulation.The shortcomings are pointed out and the directions of future development are discussed.In the end,the study highlighted the following key areas that require further research and improvement:the evaluation criteria of power system security and stability should be improved to ensure the secure and stable operation of China’s power systems;the operational control standards should be constantly enhanced to increase the reliability and flexibility of operational control strategies;generatorgrid coordination standards should be upgraded to improve the coordination between the generator control protection system and the grid;and the simulation methodology should be standardized in future power system security and stability research.展开更多
The traditional“three defense lines”for power systems are based on local information and static protection&control strategy,which are not suitable to modern large-scale power systems.In order to improve the secu...The traditional“three defense lines”for power systems are based on local information and static protection&control strategy,which are not suitable to modern large-scale power systems.In order to improve the security of UHV hybrid power grids,the Integrated Wide Area Protection&Control(IWAPC)is proposed in this paper by applying the new technologies of synchronized high-speed communication,which integrates“three defense lines”and promotes existing wide area protection only for security control.The IWAPC is the hierarchical protection and control system which provides the protection and control for wide area power networks to improve their reliability and security.It is divided into three levels,the local bay level,the substation integrated protection level and the wide area protection level.The wide area real-time protection and control information platform is the most important part of the IWAPC,which is based on a synchronized wide area communication network.The key technologies and new development trends include network topology analysis,wide area backup protection,wide area intelligent reclosing,wide area load shedding,wide area auto-switching,overload cutoff and transfer,transmission section protection,intelligent system splitting and dynamic stability control.It cannot only integrate three lines of defense for power system protection and control,but also improve security of the power grid.展开更多
The National Electricity Market(NEM)in Australia was suspended during June 15-23,2022,with a primary attribution to the lack of available generation capacity.This incident is noteworthy because it was the first market...The National Electricity Market(NEM)in Australia was suspended during June 15-23,2022,with a primary attribution to the lack of available generation capacity.This incident is noteworthy because it was the first market suspension in NEM’s history and took place in a major energy exporting country.In this letter,we review the outline and impacts of the incident.From the perspectives of market regulation,electricity supply,and electricity demand,we identify three underlying causes of the market suspension and offer four recommendations for the market mechanism evolution to ensure power supply security.展开更多
Climate change threatens the sustainable development and survival of the small Caribbean island nations. The continual rise in the demand and cost of the earth＇s finite hydrocarbon energy reservoir drives these count...Climate change threatens the sustainable development and survival of the small Caribbean island nations. The continual rise in the demand and cost of the earth＇s finite hydrocarbon energy reservoir drives these countries to examine the integration of renewable energy to reduce green house gas emissions whilst meeting their electrical energy demands. One possible renewable energy source is wind. Trinidad and Tobago, through its renewable energy policy, is seeking to reliably and economically integrate wind power with its conventional power generation sources. This paper assesses the adequacy of wind power generation at potential sites through the use of auto-regressive modeling and the use of Monte Carlo Simulation to evaluate the well-being indices for the combination of wind and conventional power generation. Two sites in the twin island Republic of Trinidad and Tobago were identified as case studies for the proposed methodology. Analysis of the results indicated that the methodology should be applied to sites with conditions encouraging economic feasibility of wind power generation.展开更多
Primary energy has the potential to bring challenges to the reliability,economic,and eco-friendliness of global electric power systems.The concept of electric power security are proposed,including many factors that ar...Primary energy has the potential to bring challenges to the reliability,economic,and eco-friendliness of global electric power systems.The concept of electric power security are proposed,including many factors that are not considered in power system reliability analysis,such as coal supply for power system,fuel price for electricity power market,carbon emissions of power generation,and so on.It is broader than power system reliability and security,which means that providing energy in the form of reliable,economical,and eco-friendly electric power.Following an account of existing blackout defence methods and systems,the processes of transforming various kinds of primary energy into electric power and the interactions between them are described,particularly with regard to flows of energy,capital,and information.Factors that limit the liquidity of these flows are defined as“generalized congestion”,and the challenges presented by primary energy are named“primary energy congestion”.China’s dilemma on coal supply for power generation is presented in some detail as an example of primary energy congestion.To cope with impacts of the primary energy on electric power systems,an idea is introduced to extend the scope of existing coordinated blackout defence systems to account for primary energy,which would lead to an integrated tool to provide decision support to power system operators accounting for primary energy congestion.展开更多
Load shedding is usually the last resort to balance generation and demand to maintain stable operation of the electric grid after major disturbances,such as generation trips.Current load-shedding optimisation practice...Load shedding is usually the last resort to balance generation and demand to maintain stable operation of the electric grid after major disturbances,such as generation trips.Current load-shedding optimisation practices focus mainly on the physical optimality of the network power flow to re-dispatch generation after the contingencies.This might lead to an uneven allocation of load curtailment,hence disadvantaging some loads more than others due to the network properties.Addressing this over-sight,this article introduces an innovative equity-aware load-shedding optimisation model emphasising a fair allocation of load curtailment across the network.First,a novel equity indicator for load shedding is proposed based on the concept of the Gini coefficient.Then,the equity constraint is integrated into an alternating-current optimal power flow(ACOPF)-based optimi-sation framework.Case studies performed on the IEEE 14-bus and 118-bus systems highlight the importance of equity con-siderations in determining optimal load curtailment between buses.The proposed equity-aware load-shedding model offers grid operators a potential alternative strategy to select alternatives.展开更多
In order to overcome the shortages of diagnostic method for distribution networks considering the reliability assessment,this paper proposed a method based on power supply safety standards.It profoundly analyzed the s...In order to overcome the shortages of diagnostic method for distribution networks considering the reliability assessment,this paper proposed a method based on power supply safety standards.It profoundly analyzed the security standard of supply for urban power networks,and established quantitative indicators of load groups based on different fault conditions.Then a method suitable for diagnostic evaluation of urban distribution networks in China was given.In the method,“N-1”calibration analysis of the distribution network was conducted.Then the results are compared with quantitative indicators of load groups on different conditions deriving the diagnostic conclusions and the standard revision is discussed.The feasibility and accuracy of the method is finally verified in the case study.展开更多
Due to the increasing implementation of high voltage direct current(HVDC)and the integration of renewable resources,frequency stability problems in power systems are drawing greater attention in recent years.It has be...Due to the increasing implementation of high voltage direct current(HVDC)and the integration of renewable resources,frequency stability problems in power systems are drawing greater attention in recent years.It has become necessary to carry out online frequency security assessments to ensure the safe operation of power systems.Considering the low time-efficiency of simulation-based methods,analytical models,such as the frequency nadir prediction(FNP)model,are more suitable for online assessment,which requires calculating the worst frequency deviation under various contingencies.Based on the FNP model,the FNP-L model for online frequency security assessment is proposed in this paper.The proposed model implements security assessment by calculating and checking the frequency features,including the nadir time and frequency,followed by contingencies.The effect of the governor,including nonlinear constraints,is approximated into polynomial functions so that the results are obtained by solving multiple polynomial equations.Case studies are carried out using the New-England 39-bus system and a regional power grid,which shows that the proposed model could achieve both high speed and high accuracy,and can therefore be applied in online security assessment.展开更多
A power balance static random-access memory（SRAM） for resistance to differential power analysis（DPA） is proposed. In the proposed design, the switch power consumption and short-circuit power consumption are balanc...A power balance static random-access memory（SRAM） for resistance to differential power analysis（DPA） is proposed. In the proposed design, the switch power consumption and short-circuit power consumption are balanced by discharging and pre-charging the key nodes of the output circuit and adding an additional shortcircuit current path. Thus, the power consumption is constant in every read cycle. As a result, the DPA-resistant ability of the SRAM is improved. In 65 nm CMOS technology, the power balance SRAM is fully custom designed with a layout area of 5863.6 μm^2.The post-simulation results show that the normalized energy deviation（NED） and normalized standard deviation（NSD） are 0.099% and 0.04%, respectively. Compared to existing power balance circuits, the power balance ability of the proposed SRAM has improved 53%.展开更多
文摘With the development of information networks, the problem of power security has increasingly caused many attention of people, but the simple power security defense system has been difficult to meet the current complex network environment. Aiming at this situation, by using the method of T-S fuzzy neural network model to analyze the characteristics of the data transmission in network, it has obtained corresponding threat information. By processing these threat information, it completes the construction of three-dimensional power security defense system. The paper carries on the corresponding data training methods by using T-shirt model fuzzy neural network, which has certain reference significance for the data analysis of other similar fields. At the same time, the study of building on the three-dimensional power security defense system aims to provide a theoretical reference for solving the security defense of the current complex network environment.
基金supported by National Key Research and Development Plan of China(No.2022YFB3103304).
文摘False Data Injection Attacks(FDIAs)pose a critical security threat to modern power grids,corrupting state estimation and enabling malicious control actions that can lead to severe consequences,including cascading failures,large-scale blackouts,and significant economic losses.While detecting attacks is important,accurately localizing compromised nodes or measurements is even more critical,as it enables timely mitigation,targeted response,and enhanced system resilience beyond what detection alone can offer.Existing research typically models topological features using fixed structures,which can introduce irrelevant information and affect the effectiveness of feature extraction.To address this limitation,this paper proposes an FDIA localization model with adaptive neighborhood selection,which dynamically captures spatial dependencies of the power grid by adjusting node relationships based on data-driven similarities.The improved Transformer is employed to pre-fuse global spatial features of the graph,enriching the feature representation.To improve spatio-temporal correlation extraction for FDIA localization,the proposed model employs dilated causal convolution with a gating mechanism combined with graph convolution to capture and fuse long-range temporal features and adaptive topological features.This fully exploits the temporal dynamics and spatial dependencies inherent in the power grid.Finally,multi-source information is integrated to generate highly robust node embeddings,enhancing FDIA detection and localization.Experiments are conducted on IEEE 14,57,and 118-bus systems,and the results demonstrate that the proposed model substantially improves the accuracy of FDIA localization.Additional experiments are conducted to verify the effectiveness and robustness of the proposed model.
文摘How to comprehensively consider the power flow constraints and various stability constraints in a series of power system optimization problems without affecting the calculation speed is always a problem.The computational burden of probabilistic security assessment is even more unimaginable.In order to solve such problems,a security region(SR)methodology is proposed,which is a brand-new methodology developed on the basis of the classical point-wise method.Tianjin University has been studying the SR methodology since the 1980s,and has achieved a series of original breakthroughs that are described in this paper.The integrated SR introduced in this paper is mainly defined in the power injection space,and includes SRs to ensure steady-state security,transient stability,static voltage stability,and smalldisturbance stability.These SRs are uniquely determined for a given network topology(as well as location and clearing process for transient faults)and given system component parameters,and are irrelevant to operation states.This paper presents 11 facts and related remarks to introduce the basic concepts,composition,dynamics nature,and topological and geometric characteristics of SRs.It also provides a practical mathematical description of SR boundaries and fast calculation methods to determine them in a concise and systematic way.Thus,this article provides support for the systematic understanding,future research,and applications of SRs.The most critical finding on the topological and geometric characteristics of SRs is that,within the scope of engineering concern,the practical boundaries of SRs in the power injection space can be approximated by one or a few hyperplanes.Based on this finding,the calculation time for power system probabilistic security assessment(i.e.,risk analysis)and power system optimization with security constraints can be decreased by orders of magnitude.
基金support by National Natural Science Foundation of China(61202354,51507084)Nanjing University of Post and Telecommunications Science Foundation(NUPTSF)(NT214203)
文摘Power system security and stability is very important to national economy and people's life,so it has been paid great attention by governments and power utilities.In order to avoid huge economic losses caused by large-scale blackouts,State Grid Corporation of China(SGCC)have invested sufficient human and financial resources to carry out related researches,and remarkable achievements have been achieved.However,large grid stability problem is very complex,it is still difficult to completely avoid the blackouts.
文摘In this paper,a series of major policy decisions used to improve the power grid reliability,reduce the risk and losses of major power outages,and realize the modernization of 21st century power grid are discussed. These decisions were adopted by American government and would also be helpful for the strategic development of Chinese power grid. It is proposed that China should take precaution,carry out security research on the overall dynamic behaviour characteristics of the UHV grid using the complexity theory,and finally provide safeguard for the Chinese UHV grid. It is also pointed out that,due to the lack of matured approaches to controll a cascading failure,the primary duty of a system operator is to work as a "watchdog" for the grid operation security,eliminate the cumulative effect and reduce the risk and losses of major cascading outages with the help of EMS and WAMS.
文摘Electricity network is a very complex entity that comprises several components like generators, transmission lines, loads among others. As technologies continue to evolve, the complexity of the electricity network has also increased as more devices are being connected to the network. To understand the physical laws governing the operation of the network, techniques such as optimal power flow (OPF), Economic dispatch (ED) and Security constrained optimal power flow (SCOPF) were developed. These techniques have been used extensively in network operation, planning and so on. However, an in-depth presentation showcasing the merits and demerits of these techniques is still lacking in the literature. Hence, this paper intends to fill this gap. In this paper, Economic dispatch, optimal power flow and security-constrained optimal power flow are applied to a 3-bus test system using a linear programming approach. The results of the ED, OPF and SC-OPF are compared and presented.
文摘After the digital revolution, the power system security becomes an important issue and it urges the power producers to maintain a well secured system in order to supply a quality power to the end users. This paper presents an integrated Corrective Security Constrained Optimal Power Flow (CSCOPF) with Flexible Transmission Line Impedance (FTLI) to enhance the power system security. The corrective approach of SCOPF is chosen, because it allows the corrective equipment to bring back the system to a stable operating point and hence, it offers high flexibility and better economics. The concept of FTLI arises from the ability of FACTS devices such as Thyristor Controlled Series Capacitor (TCSC), which can vary the line reactance to a certain extent. An enhanced security can be achieved by incorporating FTLI into the CSCOPF problem, since the power flow in a system is highly dependent on the line reactance. FTLI based CSCOPF can reduce the amount of rescheduling of generators, but it will result in an increased number of variables and thus, the complexity to the optimization process is increased. This highly complex problem is solved by using nonlinear programming. The AC based OPF model is preferred, since the corrective security actions require highly accurate solutions. IEEE 30 bus system is used to test the proposed scheme and the results are compared with the traditional CSCOPF. It can be seen that the proposed idea provides a notable improvement in the reduction of cost incurred for restoring the system security.
基金funded by State Grid Shandong Electric Power Company Technology Project(520626220110).
文摘With the increasing penetration of renewable energy in power system,renewable energy power ramp events(REPREs),dominated by wind power and photovoltaic power,pose significant threats to the secure and stable operation of power systems.This paper presents an early warning method for REPREs based on long short-term memory(LSTM)network and fuzzy logic.First,the warning levels of REPREs are defined by assessing the control costs of various power control measures.Then,the next 4-h power support capability of external grid is estimated by a tie line power predictionmodel,which is constructed based on the LSTMnetwork.Finally,considering the risk attitudes of dispatchers,fuzzy rules are employed to address the boundary value attribution of the early warning interval,improving the rationality of power ramp event early warning.Simulation results demonstrate that the proposed method can generate reasonable early warning levels for REPREs,guiding decision-making for control strategy.
基金This research was supported by the Energy Cloud R&D Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science,ICT(NRF2019M3F2A1073385).
文摘An analysis of the recent major security incidents related to industrial control systems,revealed that most had been caused by company employees.Therefore,enterprise security management systems have been developed to focus on companies’personnel.Nonetheless,several hacking incidents,involving major companies and public/financial institutions,were actually attempted by the cooperative firms or the outsourced manpower undertaking maintenance work.Specifically,institutions that operate industrial control systems(ICSs)associated with critical national infrastructures,such as traffic or energy,have contracted several cooperative firms.Nonetheless,ICT’s importance is gradually increasing,due to outsourcing,and is the most vulnerable factor in security.This paper proposes a virtualized security management scheme for the resident cooperative firms in the industrial control infrastructure.Since such companies often cannot afford adequate investment in security,the scheme is to let an ICS company provide the virtualized system.One of its merits is the convenience of controlling a VDI server at the center.The cooperative firms were classified,based on their respective security levels,and statistics were collected throughout a four-year period for the results.This paper analyzes the policies and virtualization systems that have been applied to the security of the partner companies,which engaged in ICS security.A suitable model for ICS security was then proposed by analyzing their effects on the system efficiencies,based on the comparisons of the security inspection results obtained before and after virtualization.The proposed system is expected to contribute to industrial safety.
基金National Nature Science Foundation of China (No.50477039 No.50677020)National High Technology Research and Development Program of China("863"Program) (No.2007AA04Z425)
文摘Based on the measured data of geomagnetically induced currents （GIC） in Guangdong Ling＇ ao 500 kV power networks during several magnetic storms at the peak years of 23rd Solar Cycle, the GIC calculation results of 750 kV planning power grid in Shartxi, Gansu, Qinghai and Ningxia, the structure and characteristics of power networks from 500 kV to 1 000 kV, and super magnetic storm in 1859 are analyzed in this paper. Through the analysis, the possible impacts of extreme space weather on the future ultra-high voltage （UHV） grid, the security of large-scale power system in China are expounded, and the research suggestions coping with the strong solar storms are proposed.
文摘In developing power grids,setting standards is critical to its success.The development of China’s power industry has proposed new requirements for power systems to ensure secure and stable operations.The principal standards for the security and stability of China’s current power systems are analyzed in terms of operational control,generator-grid coordination and simulation.The shortcomings are pointed out and the directions of future development are discussed.In the end,the study highlighted the following key areas that require further research and improvement:the evaluation criteria of power system security and stability should be improved to ensure the secure and stable operation of China’s power systems;the operational control standards should be constantly enhanced to increase the reliability and flexibility of operational control strategies;generatorgrid coordination standards should be upgraded to improve the coordination between the generator control protection system and the grid;and the simulation methodology should be standardized in future power system security and stability research.
文摘The traditional“three defense lines”for power systems are based on local information and static protection&control strategy,which are not suitable to modern large-scale power systems.In order to improve the security of UHV hybrid power grids,the Integrated Wide Area Protection&Control(IWAPC)is proposed in this paper by applying the new technologies of synchronized high-speed communication,which integrates“three defense lines”and promotes existing wide area protection only for security control.The IWAPC is the hierarchical protection and control system which provides the protection and control for wide area power networks to improve their reliability and security.It is divided into three levels,the local bay level,the substation integrated protection level and the wide area protection level.The wide area real-time protection and control information platform is the most important part of the IWAPC,which is based on a synchronized wide area communication network.The key technologies and new development trends include network topology analysis,wide area backup protection,wide area intelligent reclosing,wide area load shedding,wide area auto-switching,overload cutoff and transfer,transmission section protection,intelligent system splitting and dynamic stability control.It cannot only integrate three lines of defense for power system protection and control,but also improve security of the power grid.
基金supported by the National Natural Science Foundation of China (No.U2166201)China Postdoctoral Science Foundation (No.2022TQ0206)。
文摘The National Electricity Market(NEM)in Australia was suspended during June 15-23,2022,with a primary attribution to the lack of available generation capacity.This incident is noteworthy because it was the first market suspension in NEM’s history and took place in a major energy exporting country.In this letter,we review the outline and impacts of the incident.From the perspectives of market regulation,electricity supply,and electricity demand,we identify three underlying causes of the market suspension and offer four recommendations for the market mechanism evolution to ensure power supply security.
文摘Climate change threatens the sustainable development and survival of the small Caribbean island nations. The continual rise in the demand and cost of the earth＇s finite hydrocarbon energy reservoir drives these countries to examine the integration of renewable energy to reduce green house gas emissions whilst meeting their electrical energy demands. One possible renewable energy source is wind. Trinidad and Tobago, through its renewable energy policy, is seeking to reliably and economically integrate wind power with its conventional power generation sources. This paper assesses the adequacy of wind power generation at potential sites through the use of auto-regressive modeling and the use of Monte Carlo Simulation to evaluate the well-being indices for the combination of wind and conventional power generation. Two sites in the twin island Republic of Trinidad and Tobago were identified as case studies for the proposed methodology. Analysis of the results indicated that the methodology should be applied to sites with conditions encouraging economic feasibility of wind power generation.
基金This work is jointly supported by Major Program of National Natural Science Foundation of China(No.91024028)National High Technology Research and Development Program of China(863 Program)(No.2011AA05A105)+1 种基金SGCC Projects SGCC-MPLG003-2012the Australian Research Council(DP120101345).
文摘Primary energy has the potential to bring challenges to the reliability,economic,and eco-friendliness of global electric power systems.The concept of electric power security are proposed,including many factors that are not considered in power system reliability analysis,such as coal supply for power system,fuel price for electricity power market,carbon emissions of power generation,and so on.It is broader than power system reliability and security,which means that providing energy in the form of reliable,economical,and eco-friendly electric power.Following an account of existing blackout defence methods and systems,the processes of transforming various kinds of primary energy into electric power and the interactions between them are described,particularly with regard to flows of energy,capital,and information.Factors that limit the liquidity of these flows are defined as“generalized congestion”,and the challenges presented by primary energy are named“primary energy congestion”.China’s dilemma on coal supply for power generation is presented in some detail as an example of primary energy congestion.To cope with impacts of the primary energy on electric power systems,an idea is introduced to extend the scope of existing coordinated blackout defence systems to account for primary energy,which would lead to an integrated tool to provide decision support to power system operators accounting for primary energy congestion.
文摘Load shedding is usually the last resort to balance generation and demand to maintain stable operation of the electric grid after major disturbances,such as generation trips.Current load-shedding optimisation practices focus mainly on the physical optimality of the network power flow to re-dispatch generation after the contingencies.This might lead to an uneven allocation of load curtailment,hence disadvantaging some loads more than others due to the network properties.Addressing this over-sight,this article introduces an innovative equity-aware load-shedding optimisation model emphasising a fair allocation of load curtailment across the network.First,a novel equity indicator for load shedding is proposed based on the concept of the Gini coefficient.Then,the equity constraint is integrated into an alternating-current optimal power flow(ACOPF)-based optimi-sation framework.Case studies performed on the IEEE 14-bus and 118-bus systems highlight the importance of equity con-siderations in determining optimal load curtailment between buses.The proposed equity-aware load-shedding model offers grid operators a potential alternative strategy to select alternatives.
文摘In order to overcome the shortages of diagnostic method for distribution networks considering the reliability assessment,this paper proposed a method based on power supply safety standards.It profoundly analyzed the security standard of supply for urban power networks,and established quantitative indicators of load groups based on different fault conditions.Then a method suitable for diagnostic evaluation of urban distribution networks in China was given.In the method,“N-1”calibration analysis of the distribution network was conducted.Then the results are compared with quantitative indicators of load groups on different conditions deriving the diagnostic conclusions and the standard revision is discussed.The feasibility and accuracy of the method is finally verified in the case study.
基金This work is supported by the National Key Research&Development Program of China(No.2018YFB0904500)the Science and Technology Foundation of the State Grid Corporation of China(SGLNDK00KJJS1800236).
文摘Due to the increasing implementation of high voltage direct current(HVDC)and the integration of renewable resources,frequency stability problems in power systems are drawing greater attention in recent years.It has become necessary to carry out online frequency security assessments to ensure the safe operation of power systems.Considering the low time-efficiency of simulation-based methods,analytical models,such as the frequency nadir prediction(FNP)model,are more suitable for online assessment,which requires calculating the worst frequency deviation under various contingencies.Based on the FNP model,the FNP-L model for online frequency security assessment is proposed in this paper.The proposed model implements security assessment by calculating and checking the frequency features,including the nadir time and frequency,followed by contingencies.The effect of the governor,including nonlinear constraints,is approximated into polynomial functions so that the results are obtained by solving multiple polynomial equations.Case studies are carried out using the New-England 39-bus system and a regional power grid,which shows that the proposed model could achieve both high speed and high accuracy,and can therefore be applied in online security assessment.
基金Project supported by the Zhejiang Provincial Natural Science Foundation of China(No.LQ14F040001)the National Natural Science Foundation of China(Nos.61274132,61234002)the K.C.Wong Magna Fund in Ningbo University,China
文摘A power balance static random-access memory（SRAM） for resistance to differential power analysis（DPA） is proposed. In the proposed design, the switch power consumption and short-circuit power consumption are balanced by discharging and pre-charging the key nodes of the output circuit and adding an additional shortcircuit current path. Thus, the power consumption is constant in every read cycle. As a result, the DPA-resistant ability of the SRAM is improved. In 65 nm CMOS technology, the power balance SRAM is fully custom designed with a layout area of 5863.6 μm^2.The post-simulation results show that the normalized energy deviation（NED） and normalized standard deviation（NSD） are 0.099% and 0.04%, respectively. Compared to existing power balance circuits, the power balance ability of the proposed SRAM has improved 53%.
