AN INDUCTANCE CALCULATION MODEL OF POWER TRANSFORMER FOR INTERNAL FAULT ANALYSIS
Wang Zanji1 ,L iu Xiucheng1 ,Chen Xianghui2 1.Tsinghua U niversity,Beijing 1000 84,China 2 .Shenyang Transformer CoLtd,Shenyang110025 ,China
For the purpose of precious internal faultanalysis and relay protection of the power transform er,some problem s in the existing m odels are pointed out.The key problem is that the difference of the leakage m agnetic field distribution between normal operation and fault condition has not been taken into account.Therefore,the original short circuit reactance or leakage inductance of the transformer can't be used to develop the model param eters of the faulty transformer.This paper presents a new method to determ ine the leakage inductance of a power transformer. Based on the principle of linear superposition of the leakage magnetic field,the leakage inductance of the faulty transform er is firstly calculated on the basis of the geom etric dim ensions of the windings by subdividing windings into several sections according to the fault location.Then, the obtained inductance m atrix will be m odified according to the conceptthat the sum of the am pere- turns of all harmonics in the transformer windings is equal to zero.The application of the proposed m ethod has shown that the method has the flexibility and sufficient precision in the internal fault analysis.
【CateGory Index】： TM41