Abstract: With the wide application of series capacitor compensation（SC） technique to the power grid of China,it becomes necessary and urgent to study the fast transient process which affects the operational reliability of the SC equipment,and further to take necessarily preventive measures.The extraction method of partial inductance matrix was studied in order to meet the partial element equivalent circuit（PEEC） modeling demand of multi-conductors system in compensation equipment.The complete set describing any spatial relationship of segment pairs was constructed;a universal engineering calculation method was designed for the partial inductance of complicated multi-conductor system by assigning specific analytical formula to each element in set.Experiments show that the accuracy of calculation results by the program（LPCal） proposed in this paper can meet the requirement of engineering calculation of fast transient overvoltage.