Stability Analysis For Power System Based On Battery Energy Storage Equipment

In traditional power grid, power generation, transmission, distribution and consumption are almost completed at the same time, which requires power balance among all the aspects, so traditional power grid have a "rigid" feature. As a device which can store chemical energy and transmit the stored energy into electrical power in bi-direction, Battery Energy Storage System (BESS) can change the "rigid" system into a "flexible" one, and will help improve the use ratio of grid facilities, enhance the flexibility of grid operation, and maintain system voltage and frequency stability. The application of energy storage technology in energy regulation and management, in dynamic power compensation greatly increases the power grid control initiative. Because of its larger storage capacity, shorter discharge response time, lower demand for space, longer life and higher efficiency, BESS is more suitable for different applications with great prospects and potential applications, and it will be one of the most important energy storage in the future.Firstly, this thesis derives the equivalent increment expression of energy storage device on the electromagnetic torque of generator by analysis of electromagnetic torque of a single machine infinite system based on the Hefrron-Philips model. And the effectiveness of two proportional control strategies, one basing on the power deviation and the other basing on the rotor angular velocity deviation are compared in analytical solution which makes a proof that with appropriate control strategies the energy storage device can enhance the stability of the system.Energy storage device CBEST and its controller model are established in the power system simulation software PSS/E. And the effectiveness of two proportional control strategies are compared.lt also simulates the effect of CBEST with different locations and controller parameters.Referring to the Site Selection Methods of FACTS devices for CBEST, the residue method and eigenvector method are used to select the best mounting location. The residue modulus and eigenvector modulus at different operating conditions ares solved, then the CBEST location priorities are sorted. Finally, the optimal locations are simulated under various conditions by setting different faults at different locations in IEEE9-bus system to compare the effectiveness of residue indicators with eigenvector indicators.BESS used in power system stability control has broad prospects. That analyzing the impact of BESS to the generator synchronous torque using analytical solution gives us a better insight into the nature of energy storage to improve power system stability, which can provide a reference for the design of the BESS controller. The residue method and eigenvector method used in energy storage devices location selection in small systems has a guiding significance in the analysis of large-scale power systems to optimize the layout of energy storage device.