Research on Optimization of Multifunction Control Using Energy Storage Systems

本研究的目的是在未来的电力系统中，利用分散的储能系统作为主控制器来实现良好的质量控制，这是现有设备难以实现的。研究了分散储能系统的负荷频率控制、电压无功控制、电力系统稳定控制、负荷均衡等多种功能的优化方法；对于分散储能系统的频率和有功功率控制，建立了基本的负荷频率控制模型，并对其进行了改进。通过计算机模拟对其进行了评价。然后基于该模型实现了一种负载均衡模式，并对其特性进行了研究。因此，我们得到了储能系统与现有发电机合作时的最优负荷频率控制准则。类似地，研究了分散储能系统的电压和无功控制。并与现有的VQC或SVC进行了比较，考虑了与实际功率控制的配合以及AC-DC转换器和储能的局限性，对控制性能进行了检验。结果表明，储能系统的无功功率、交直流变换容量、储能能量和P/Q比受无储能母线电压特性等电力系统特性的影响，并从预防控制的角度研究了分散储能系统的电力系统稳定控制，以提高暂态稳定性。因此，人们认识到，在瞬时稳定效果和预防性控制成本之间存在权衡关系。然而，也有研究表明，分散储能系统的使用拓宽了运营商在电力系统运行中的选择范围。

This research aimed at realization of good quality control by using dispersed energy storage systems as main controllers in future power systems, which was difficult to realize by existing facilities only. The optimization methods for plural functions expected to dispersed energy storage systems, such as load frequency control, voltage and reactive power control, and power system stabilizing control, as well as load leveling, were investigated.As regards frequency and real power control using dispersed energy storage systems, we have constructed basic load frequency control model, and have improved it by PID controller. It was evaluated by computer simulation. Then a load leveling mode was realized based on the model, and its characteristics were investigated. As a result, we have obtained guidelines for the optimal load frequency control where energy storage systems have cooperated with existing generators.Similarly, voltage and reactive power control using dispersed energy storage systems was investigated. And then the control performance was examined by comparing with existing VQC or SVC considering cooperation with real power control and limits of ac-dc converter and stored energy. As a result, it was revealed that the reactive power of energy storage system, ac-dc converter capacity.stored energy and P : Q ratio are influenced by power system characteristics such as voltage characteristics of the buses with no energy storage system.Moreover, we have investigated the power system stabilizing control using dispersed energy storage systems from the viewpoint of preventive control to improve transient stability. As a result it was recognized that there was a trade-off relationship between the transient stabilizing effect and the cost for preventive control. However, it was also revealed that operators choices in power system operation were widened by using dispersed energy storage systems.