Computation of the Reactive Power Compensation Capacity of 500kV substations for the transmission lines

摘要

More equipments for reactive power compensation is need to be set up in many 500kV substations in Guangdong province due to the increment of the load of the power grid. An important cause of inreasing reactive power requirement of the power system is that the reactive power consumed by the transmission lines under heavy load is increased. The reactive power consumption of the power transmission lines is analyzed. The relation between the load and the reactive power consumption of the transmission lines is derived by the transmission characteristic equations of power lines. A practical calculating method is proposed for reactive power consumption of the transmission lines. The method is used to compute the reactive power consumption of the 500kV Xubei line in different operational mode, and of the 500kV lines of Beijiao substation under 50% Load Factor.