In recent years

the economy of Tangshan developed rapidly

as a result

the consumption of electricity increased substantially.The steel plants play an important role in the power load increment

they worsen the power quality

even affect the regular production and operation of the power system.Therefore

it is important and urgent to solve the power quality problems caused by the fast-speed varying loads.Research and manufacture the 10kV thyristor controlled reactor type Static Var Compensator（SVC） which adopts the instantaneous reactive power theory as the new control strategy can improve the power quality of the substation efficiently.