Planning of flexible power sources in power distribution systems with high penetration of dispersed generation

Abstract

With the wide application of dispersed generations (DG), power distribution systems are transferring from passive to active. Acting as important composition of DG, wind turbine (WT) and photovoltaic (PV) are developing quickly in these years for their clean and renewable. In high penetration scenarios, as the power outputs of WT and PV are uncontrollable, the volatility and intermittency of WT and PV power make the net load curve a ‘duck curve’, and the flexibility and ramping needs become significant, which may threaten the security and reliability of power system operation. Thus, to allocate enough flexible power sources are essential. Based on the definition of power system flexibility, the characteristics of power system flexibility and flexible sources are first analysed. Then, a quantitative evaluation model of power system flexibility, which appears in a probability form, is proposed and solved using Monte Carlo simulation method. After that, on the basis of flexibility improvement, the siting and sizing problems of flexible sources are discussed. Finally, case studies are made on the IEEE 33-bus test system to verify the validity of the model and method proposed, and several conclusions are obtained.