Heihe power grid is located in the end of north Heilongjiang power grid and is connected to the main grid through a long line and long chain structure and

at the same time

is responsible for the Russian power injection.The short circuit capacity of this system is low while the transmission power fluctuation is large.The voltage along the line shows such trend as low on the both ends but high in the middle and the difference of voltage is high.The construction of 500 kV Anbei station increases length of long-chain grid further

causing the reactive voltage of the system more difficult to be controlled.In this paper

starting from the actual operation and with comprehensive consideration of the need of multiple operation mode such as normality

maintenance

charge and a heavy fault

the principle

process and method of reactive power optimization of long distance

long-chain and weak system are proposed.And the reactive optimization plan of Anbei 500 kV power transmission and transformation project is optimized.