新型换流变压器的差动保护及整定计算

Differential protection and setting calculation of new-type converter transformer

针对新型换流变压器特殊的绕组接线型式,在建立其电流变换矩阵的基础上,提出了新型换流变压器的差动保护接线方案。采用三折线比率制动特性,综合考虑了变压器正常运行时的不平衡电流、电流互感器性能及内部匝间短路时流出电流等影响因素,对新型换流变压器的差动保护整定值进行了计算。最后,以实际新型换流变压器的数据为依据,建立了相应的差动保护方案仿真模型,通过对变压器多种运行状态进行仿真分析,验证了本文提出的保护方案的可行性和整定计算的正确性。

Aiming at the special winding connection of the new-type converting transformer, the connecting scheme of differential protection is proposed based on the establishment of the current transform matrix. Adopting the ratio braking characteristic with three-broken lines, and taking these effects into account including the unbalance current under the normal condition, current-transformer performance and existing output current when occurring internal fault, the setting values for the differential protection of the new-type converting transformer are calculated. At last, the simulation model of the differential protection is established based on the new-type converting transformer tech- nical parameters. By means of the simulating analysis of various operating conditions of the transformer, the feasibility of the proposed scheme and the correctness of the setting calculation are verified.