In some countries, there exists a risk of power deficit in the EPS （electrical power system）. This is a very serious problem and there are various solutions to deal with it. A power deficit in the EPS leads to frequ...In some countries, there exists a risk of power deficit in the EPS （electrical power system）. This is a very serious problem and there are various solutions to deal with it. A power deficit in the EPS leads to frequency decrease in the power system. A dedicated automation to load shedding is used to maintain proper EPS operation. For some time, it has applied a mechanism called demand-side response, which in case of an emergency situation allows for a ＂more civilized＂ rationing of electricity to customers, with their consent. Such programs require that the utilities pay the customers for their agreement. The author proposes a new solution, intermediate between strict ALS （acting relieving automation） and demand-side response programs, where the companies have to send information about the price of energy or control signals to households.展开更多
Under-frequency load shedding （UFLS） is used in the power industry to rescue systems facing extreme disturbances to avoid system collapse. Traditionally, many computations are repeated to seek the proper power syste...Under-frequency load shedding （UFLS） is used in the power industry to rescue systems facing extreme disturbances to avoid system collapse. Traditionally, many computations are repeated to seek the proper power system settings such that the UFLS provides the desired good performance for selected scenarios. An adaptive UFLS method based on the genetic algorithm was developed to automate the finding of optimal parameters to minimize the repetitive trial-error calculations. Simulations demonstrate that the method has better performance than previous schemes and reduces the time and effort of the repetitive simulations.展开更多
Under-frequency load shedding(UFLS)serves as the very last resort for preventing total blackouts and cascading events.Fluctuating operating conditions and weak resilience of the future grid require UFLS adapt to vario...Under-frequency load shedding(UFLS)serves as the very last resort for preventing total blackouts and cascading events.Fluctuating operating conditions and weak resilience of the future grid require UFLS adapt to various operating conditions and non-envisioned faults.This paper develops a novel data-enabled Koopman-based load shedding(KLS)to achieve the optimal one-shot load shedding for power system frequency safety.The KLS yields a network that facilitates a coordinate transformation from the delay-embedded space to a new space,wherein the dynamics can be expressed in a linear manner.The network is specifically tailored to effectively track parameter variations in the dynamic model of the power system.Linear dynamics support the development of a real-time decided load shedding strategy,while parameter tracking enables the adaptability of the KLS to non-envisioned operating conditions and faults.To address approximation inaccuracies and the discrete nature of load shedding,a safety margin tuning scheme is integrated into the KLS framework,ensuring that the system frequency trajectory remains within the safety range.Simulation results show the adaptability,prediction capability,and control effect of the proposed KLS.展开更多
Recently,the fast frequency response(FFR)service by large-scale battery energy storage systems(BESSs)has been successfully proved to arrest the frequency excursion during an unexpected power outage.However,adequate fr...Recently,the fast frequency response(FFR)service by large-scale battery energy storage systems(BESSs)has been successfully proved to arrest the frequency excursion during an unexpected power outage.However,adequate frequency response relies on proper evaluation of the contingency reserve of BESSs.The BESS FFR reserve is commonly managed under fixed contracts,ignoring various response characteristics of different BESSs and their coexisting interactions.This paper proposes a new methodology based on dynamic grid response and various BESS response characteristics to optimise the FFR reserves and prevent the frequency from breaching the under-frequency load shedding(UFLS)thresholds.The superiority of the proposed method is demonstrated to manage three large-scale BESSs operating simultaneously in an Australian power grid under high renewable penetration scenarios.Further,the proposed method can identify remaining battery power and energy reserve to be safely utilised for other grid services(e.g.,energy arbitrage).The results can provide valuable insights for integrating FFR into conventional ancillary services and techno-effective management of multiple BESSs.展开更多
Dynamic behaviour of frequency is crucial for power system operation and control.Several frequency response models have been proposed to reveal frequency dynamics from different aspects.A comprehensive software packag...Dynamic behaviour of frequency is crucial for power system operation and control.Several frequency response models have been proposed to reveal frequency dynamics from different aspects.A comprehensive software package incorporating major frequency response models is needed for analysis and control of power system frequency dynamics.In this paper,an approach for developing a programmable and open software package for frequency response studies is proposed.The framework of the package is extendable with reduced frequency response models.Essential models for frequency response study are included,e.g.,generator,load,and under-frequency load shedding(UFLS).The provided application program interfaces(APIs)enable simulation with high-level languages by calling dynamic link library and makes the package programmable.An advanced application module is developed for quantitative assessment of transient frequency deviation.APIs can also be used for model extension and secondary development.To demonstrate the usage of the package,several examples are illustrated to explain how to perform simulations with the package,and to perform advanced applications using scripting with the provided APIs.展开更多
文摘In some countries, there exists a risk of power deficit in the EPS （electrical power system）. This is a very serious problem and there are various solutions to deal with it. A power deficit in the EPS leads to frequency decrease in the power system. A dedicated automation to load shedding is used to maintain proper EPS operation. For some time, it has applied a mechanism called demand-side response, which in case of an emergency situation allows for a ＂more civilized＂ rationing of electricity to customers, with their consent. Such programs require that the utilities pay the customers for their agreement. The author proposes a new solution, intermediate between strict ALS （acting relieving automation） and demand-side response programs, where the companies have to send information about the price of energy or control signals to households.
文摘Under-frequency load shedding （UFLS） is used in the power industry to rescue systems facing extreme disturbances to avoid system collapse. Traditionally, many computations are repeated to seek the proper power system settings such that the UFLS provides the desired good performance for selected scenarios. An adaptive UFLS method based on the genetic algorithm was developed to automate the finding of optimal parameters to minimize the repetitive trial-error calculations. Simulations demonstrate that the method has better performance than previous schemes and reduces the time and effort of the repetitive simulations.
基金supported by National Key R&D Program of China(No.2021YFB2400800).
文摘Under-frequency load shedding(UFLS)serves as the very last resort for preventing total blackouts and cascading events.Fluctuating operating conditions and weak resilience of the future grid require UFLS adapt to various operating conditions and non-envisioned faults.This paper develops a novel data-enabled Koopman-based load shedding(KLS)to achieve the optimal one-shot load shedding for power system frequency safety.The KLS yields a network that facilitates a coordinate transformation from the delay-embedded space to a new space,wherein the dynamics can be expressed in a linear manner.The network is specifically tailored to effectively track parameter variations in the dynamic model of the power system.Linear dynamics support the development of a real-time decided load shedding strategy,while parameter tracking enables the adaptability of the KLS to non-envisioned operating conditions and faults.To address approximation inaccuracies and the discrete nature of load shedding,a safety margin tuning scheme is integrated into the KLS framework,ensuring that the system frequency trajectory remains within the safety range.Simulation results show the adaptability,prediction capability,and control effect of the proposed KLS.
文摘Recently,the fast frequency response(FFR)service by large-scale battery energy storage systems(BESSs)has been successfully proved to arrest the frequency excursion during an unexpected power outage.However,adequate frequency response relies on proper evaluation of the contingency reserve of BESSs.The BESS FFR reserve is commonly managed under fixed contracts,ignoring various response characteristics of different BESSs and their coexisting interactions.This paper proposes a new methodology based on dynamic grid response and various BESS response characteristics to optimise the FFR reserves and prevent the frequency from breaching the under-frequency load shedding(UFLS)thresholds.The superiority of the proposed method is demonstrated to manage three large-scale BESSs operating simultaneously in an Australian power grid under high renewable penetration scenarios.Further,the proposed method can identify remaining battery power and energy reserve to be safely utilised for other grid services(e.g.,energy arbitrage).The results can provide valuable insights for integrating FFR into conventional ancillary services and techno-effective management of multiple BESSs.
基金National Natural Science Foundation of China(No:51477092).
文摘Dynamic behaviour of frequency is crucial for power system operation and control.Several frequency response models have been proposed to reveal frequency dynamics from different aspects.A comprehensive software package incorporating major frequency response models is needed for analysis and control of power system frequency dynamics.In this paper,an approach for developing a programmable and open software package for frequency response studies is proposed.The framework of the package is extendable with reduced frequency response models.Essential models for frequency response study are included,e.g.,generator,load,and under-frequency load shedding(UFLS).The provided application program interfaces(APIs)enable simulation with high-level languages by calling dynamic link library and makes the package programmable.An advanced application module is developed for quantitative assessment of transient frequency deviation.APIs can also be used for model extension and secondary development.To demonstrate the usage of the package,several examples are illustrated to explain how to perform simulations with the package,and to perform advanced applications using scripting with the provided APIs.
