Research On Power Grid Side Voltage Control Strategy Of New Energy Incorporated Into Distribution Network

With the development of new energy sources,more and more wind farms and photovoltaic power stations are connected to the distribution network in Dalian,and most of the new energy power generation is concentrated in the Wafangdian area of Dalian,and the new energy power generation has an impact on the voltage and reactive of the distribution network.When the distribution network reverses the reactive power to the 220 kV network,the system voltage will increase and the line loss will increase.Therefore,in order to reduce the transmission of reactive power in the power grid,reactive power local balance should be achieved.The voltage control in the Dalian is now mainly based on the Automatic Voltage Control(AVC),which is achieved by inputting and removing capacitors and adjusting transformer tap position.Neither of these two methods can solve the problem of reactive power inversion.In recent years,new energy power stations have been equipped with static reactive power compensators to compensate for the reactive power generated by generating units;However,it is found that the static reactive power compensator of the new energy power station can't fully realize the reactive power local balance,and it needs to cooperate with the substation.The reactor is a kind of reactive power compensation device with mature technology,simple and low cost.This paper adds the reactor on the basis of the voltage control of substation,forms voltage control strategy of the parallel capacitor and reactor,and supplements the reactive power of new energy generation to distribution network by putting in the parallel reactor.For the characteristics of capacitors and reactors and the interaction between them,the voltage control strategy of the substation is optimized: improve the nine-zone control strategy,subdivide the situation near the upper and lower limits,and form a 17-zone control strategy with capacitors and reactors.Before the pressure control equipment to perform pre-determination,in the condition that does not meet the pre-determination conditions so that the pressure control equipment can't move.For increasing the locking conditions between the parallel capacitor and reactor,priority is given to removing the capacitor or reactor when a reactive power compensation device is required;When no capacitor or reactor are detected,the reactor or capacitor is allowed to be put in.This paper takes the distribution network of 220 kV Fuzhou City Substation in Dalian as an example,the effect of the parallel reactor on reactive power of distribution network is studied based on MATLAB model and simulation,combined the voltage and reactive limit values of voltage control strategy.Through the simulation analysis and test,it is found that the parallel reactor can suppress reactive power inversion,improve the 66 kV bus voltage,and improve the voltage quality of the distribution system.The research methods and results of this paper provide an effective method for realizing reactive power local balance of new energy into distribution network.