The effects of reactive power compensation on the stable and economical operation of electric power system are introduced in this essay.Insufficiency of reactive power will reduce system voltage and power factor

thus

damage the electrical equipment

as well as cause voltage collapse

system collapse and large area blackout.The reactive power expendable equipment and compensation equipment are also introduced here.It points out that the generator’s operating in low power factor should be avoided

at the same time transmission to the remote reactive power should be prevented

which will cause voltage loss and power loss.Voltage regulation and reactive power compensation are discussed.