The rapid increase in renewable energy integration brings with it a series of uncertainty to the transmission and distribution systems.In general,large-scale wind and solar power integration always cause short-term mi...The rapid increase in renewable energy integration brings with it a series of uncertainty to the transmission and distribution systems.In general,large-scale wind and solar power integration always cause short-term mismatch between generation and load demand because of their intermittent nature.The traditional way of dealing with this problem is to increase the spinning reserve,which is quite costly.In recent years,it has been proposed that part of the load can be controlled dynamically for frequency regulation with little impact on customers’living comfort.This paper proposes a hybrid dynamic demand control(DDC)strategy for the primary and secondary frequency regulation.In particular,the loads can not only arrest the sudden frequency drop,but also bring the frequency closer to the nominal value.With the proposed control strategy,the demand side can provide a fast and smooth frequency regulation service,thereby replacing some generation reserve to achieve a lower expense.展开更多
In this work,chaos game optimization(CGO),a robust optimization approach,is employed for efficient design of a novel cascade controller for four test systems with interconnected power systems(IPSs)to tackle load-frequ...In this work,chaos game optimization(CGO),a robust optimization approach,is employed for efficient design of a novel cascade controller for four test systems with interconnected power systems(IPSs)to tackle load-frequency con-trol(LFC)difficulties.The CGO method is based on chaos theory principles,in which the structure of fractals is seen via the chaotic game principle and the fractals’self-similarity characteristics are considered.CGO is applied in LFC studies as a novel application,which reveals further research gaps to be filled.For practical implementation,it is also highly desirable to keep the controller structure simple.Accordingly,in this paper,a CGO-based controller of fractional-order(FO)proportional-integral-derivative-FO proportional-integral(FOPID-FOPI)controller is proposed,and the integral time multiplied absolute error performance function is used.Initially,the proposed CGO-based FOPID-FOPI controller is tested with and without the nonlinearity of the governor dead band for a two-area two-source model of a non-reheat unit.This is a common test system in the literature.A two-area multi-unit system with reheater-hydro-gas in both areas is implemented.To further generalize the advantages of the proposed scheme,a model of a three-area hydrothermal IPS including generation rate constraint nonlinearity is employed.For each test system,comparisons with relevant existing studies are performed.These demonstrate the superiority of the proposed scheme in reducing settling time,and frequency and tie-line power deviations.展开更多
As the existing coordinated control strategies between grid and unit have limitations in isolated power system, this paper introduces new coordinated control strategies which can improve the stability of isolated syst...As the existing coordinated control strategies between grid and unit have limitations in isolated power system, this paper introduces new coordinated control strategies which can improve the stability of isolated system operation. This paper analyzes the power grid side and unit side influence factors on the isolated power system. The dynamic models which are suitable for islanding operation are applied to simulate and analyze the stability and dynamic characteristics of the isolated power system under the conditions of different load disturbances and governor parameters. With considering the differences of frequency characteristics between the interconnected and isolated power system, the adjusting and optimization methods of under frequency load shedding are proposed to meet the frequency stability requirements simultaneously in the two cases. Not only proper control strategies of the power plant but the settings of their parameters are suggested to improve the operation stability of the isolated power system. To confirm the correctness and effectiveness of the method mentioned above, the isolated system operation test was conducted under the real power system condition, and the results show that the proposed coordinated control strategies can greatly improve stability of the isolated power system.展开更多
基金supported by the Engineering Research Center Program of the National Science Foundationthe Department of Energy of USA under NSF Award Number EEC-1041877the CURENT Industry Partnership Program.
文摘The rapid increase in renewable energy integration brings with it a series of uncertainty to the transmission and distribution systems.In general,large-scale wind and solar power integration always cause short-term mismatch between generation and load demand because of their intermittent nature.The traditional way of dealing with this problem is to increase the spinning reserve,which is quite costly.In recent years,it has been proposed that part of the load can be controlled dynamically for frequency regulation with little impact on customers’living comfort.This paper proposes a hybrid dynamic demand control(DDC)strategy for the primary and secondary frequency regulation.In particular,the loads can not only arrest the sudden frequency drop,but also bring the frequency closer to the nominal value.With the proposed control strategy,the demand side can provide a fast and smooth frequency regulation service,thereby replacing some generation reserve to achieve a lower expense.
文摘In this work,chaos game optimization(CGO),a robust optimization approach,is employed for efficient design of a novel cascade controller for four test systems with interconnected power systems(IPSs)to tackle load-frequency con-trol(LFC)difficulties.The CGO method is based on chaos theory principles,in which the structure of fractals is seen via the chaotic game principle and the fractals’self-similarity characteristics are considered.CGO is applied in LFC studies as a novel application,which reveals further research gaps to be filled.For practical implementation,it is also highly desirable to keep the controller structure simple.Accordingly,in this paper,a CGO-based controller of fractional-order(FO)proportional-integral-derivative-FO proportional-integral(FOPID-FOPI)controller is proposed,and the integral time multiplied absolute error performance function is used.Initially,the proposed CGO-based FOPID-FOPI controller is tested with and without the nonlinearity of the governor dead band for a two-area two-source model of a non-reheat unit.This is a common test system in the literature.A two-area multi-unit system with reheater-hydro-gas in both areas is implemented.To further generalize the advantages of the proposed scheme,a model of a three-area hydrothermal IPS including generation rate constraint nonlinearity is employed.For each test system,comparisons with relevant existing studies are performed.These demonstrate the superiority of the proposed scheme in reducing settling time,and frequency and tie-line power deviations.
文摘As the existing coordinated control strategies between grid and unit have limitations in isolated power system, this paper introduces new coordinated control strategies which can improve the stability of isolated system operation. This paper analyzes the power grid side and unit side influence factors on the isolated power system. The dynamic models which are suitable for islanding operation are applied to simulate and analyze the stability and dynamic characteristics of the isolated power system under the conditions of different load disturbances and governor parameters. With considering the differences of frequency characteristics between the interconnected and isolated power system, the adjusting and optimization methods of under frequency load shedding are proposed to meet the frequency stability requirements simultaneously in the two cases. Not only proper control strategies of the power plant but the settings of their parameters are suggested to improve the operation stability of the isolated power system. To confirm the correctness and effectiveness of the method mentioned above, the isolated system operation test was conducted under the real power system condition, and the results show that the proposed coordinated control strategies can greatly improve stability of the isolated power system.
