Technique research on the online detection and restraint of the induced voltage and circulating current on the metal sheath of 35kV 630mm2 single-core XLPE cable

Due to the dramatic growth of the power demand in Pudong area, Shanghai, SMEPC has applied 35kV single-core cable circuit with high strength, large section of 630mm² and length of more than 8km in its distribution system. On one hand, the single-core cable circuit with large section can improve the transmission capacity of the single cable circuit, so that less joints will be used, the pavement and its accessories installation will be convenient, the operation and maintenance expenses will drop. On the other hand, it causes the induced voltage and circulating current on the metal sheath, which will affect the secure, reliable, stable and economical operation of the cable circuit. Since the field condition of 35kV cable pavement is totally different with that of the theoretic calculation, the calculation result has big deviation with the test result. Based on the theoretic calculation and analysis, research and analysis on the field test result of the induced voltage and circulating current on the metal sheath of 35kV 630mm² single-core XLPE cable circuit, this paper assesses the soundness of the cable circuit with large section and long distance objectively and scientifically, submits the optimized solution to effectively restrain the induced voltage and circulating current.