The occurrence of the induced voltage is a universal phenomenon with the metal shield in the power cable， the method of three segments conversion being often adopted to lower the induced voltage when laying down the cable. With the development of urban construction， renovation of the power cable is becoming increasingly frequent， which often causes the length of three segments to be unequal， bringing about unbalanced induced voltage in the metal shield and the circulating current in the metal shield. Several main induced voltage models for the metal shield of power cable are deduced based on a sound analysis. The methods that add compensating unit to the end of the metal shield of power cable are then presented， which can balance the induced voltage and restrain the circulating current. Its basic principle is to sheathe the power cable in the compensating unit. When current flows through the cable， the compensating device will generate the induced electromotive force in the compensating unit. This induced electromotive force is used to offset the induced voltage of the metal shield. The calculation model of compensating inductance is obtained， and the compensating unit has been developed. Results of tests at Nanjing Power Supply Company are in agreement with those of simulation calculation. Research shows that the method proposed can effectively reduce the induced voltage and the circulating current of the metal shield as well as greatly reduce the loss of power cable.