Research On The Distribution Network Voltage Stability With Distributed Photovoltaic Connection

With the rapid development of industrial production,demand for electric power is rising,to cause the contradiction between power supply and demand being more and more obvious.Countries start using renewable energy,and an important approach is distributed power technology.Distributed generation technologies can make full use of various types of renewable energy because of its flexibility,effectively relief pressure of “power shortage”.Meanwhile,distributed power supply can be used as the alternate power supply of large power system,which can reduce the investment costs of power transmission and transformation,as well as power loss of long distance power transmission.Firstly,this paper introduces the structure of distributed PV system and sets up a simplified dynamic model of distributed PV power.Control strategy of distributed PV power when connected to power grid is designed,and model of distribution network is established.Load flow calculation is carried out in case with distributed power system.Secondly,static voltage stability index of distribution power grid and its calculation method is introduced.This paper studies on factors influencing the static voltage stability of grid-connected distributed PV power system,including influence of PV power under different load levels,location and power capacity of distributed grid-connected PV power supply.At the same time,this paper studied the two factors influencing the transient voltage of distributed grid-connected PV power based on the goal of voltage drops of key notes of system reactive power in transient process.Finally,to improve the voltage stability of distribution power network of distributed grid-connected PV power system,this paper proposed that installing distributed PV power on the key nodes of reactive power in distribution network,taking the minimum of reactive power compensation capacity and static voltage stability index L as target,and the optimal allocation of compensation capacity of reactive compensation points was depended on genetic optimization.