Abstract:Insufficient or excessive reactive power distribution of power network will cause voltage fluctuation of power network, difficulty in control and control of power network dispatch and operation, low equipment utilization rate, waste of power gird investment and other problems, which is not conducive to the safe and stable operation of power system. In this paper, Based on the review of audit of the power grid project feasibility study report, put forward the principle of power grid reactive power compensation device configuration, the basic requirements of grid and power factor compensation requirements, At the same time, on the basis of the design idea and method of reactive power compensation configuration of substation during the feasibility study stage of power grid engineering, the calculation process of reactive power load(loss) and reactive power supply in power system is combined.This paper analyses and summarizes the common problems in reactive power allocation design of power grid engineering, such as too large statistical value of reactive load, neglecting reactive power supplied by reactive power supply, neglecting switching voltage fluctuation of capacitor banks and harmonic checking, and puts forward the key points in the selection design and evaluation of reactive power compensation in substation, so as to ensure the safety of substation. On the basis of safe and reliable operation of power grid, reactive power compensation equipment should be allocated economically and rationally to improve the economic operation level of power system and save investment in power grid construction.