Research on Compensation of Induced Voltage in the Metal Shield of the High-voltage Power Cable

In order to reduce the induced voltage of the metal shield in power cable,the method of three segments conversion is often adopted.But the unequal length of three segments will make the induced voltage of the metal shield unbalanced,and produce the circulating current in the metal shield when the power cable is renovated.According to analysis,the induced voltage models of the metal shield of power cable are deduced in this paper,these models include any arrangement way of the cable at single circuit and two-circuit.The method of adding compensating unit(in fact,compensating inductance device) at the end of the metal shield of power cable is presented,which can restrain circulating current.Its basic principle is that the compensating unit is set around the power cable,when current flows through the power cable,the induced voltage arises in compensating unit,the induced voltage is used to counteract the induced voltage of the metal shield.The calculation model of compensating inductance is derived,and emulation calculation are made.Research shows that the method proposed in this paper can reduce the induced voltage of the metal shield efficiently,reduce the circulating current in the metal shield,and decrease the loss of power cable greatly.