| Energy is the reliable and indispensable element for human being. With the continuous consumption of fossil energy, energy crisis has become a serious threaten to social development and economy. Solar energy is clean and sustainable, which is gradually caused the attention all over the world. Due to the random fluctuation of solar irradiation, large-scale photovolatic(PV) power will bring challenges to the security and stability of power grid. The solar irradiance resource in our country is widely spread in northwestern area, where power grid is weak, and load level is low. PV power needs to deliver by long distance high voltage power transmission. So the harmful effects of PV power would be more serious. This paper studied PV power integration capacity from two perspectives, which are power system long-term planning and short-term operation. The major research are as follows:The external characteristic of PV is modeled, and the output characteristics of PV in different time scales are analysed. The output of PV is maximum in spring and autumn, minimum in winter, and median in summer. The output of PV in5minutes obeys normal distribution, and the capacity credit is very low. Some measures to improve PV power integration capacity are proposed based on above analysis.From the perspective of long-term planning, the effects of PV on peak load regulating is analysed, and a method to assess the PV power integration capacity is proposed, which considers regulating peak ability and tie line power. The method is analyzed on a province power system, PV power integration capacities of2015and2020are obtained.From the perspective of short-term operation, a method to assess the PV power integration capacity is proposed, which considers static voltage stability. This method takes use of chance constrained programming, which is convenient to consider the randomness of PV output and load. Static voltage stability is firstly introduced to the model. Stochastic simulation technique and particle swarm optimization algorithm are applied to solve the problem, which is verified on IEEE30bus power system. Comparison the results with traditional simulation methods, show that the proposed method is relatively accurate. The capacity limit is significantly affected by power grid structure and sources. It is important to consider the randomness of solar irradiance, static voltage stability, the confidence level of indicator qualified rates. |
