Y/D接线变压器漏感参数的识别方法

提出一种变压器漏感的识别方法，该方法无需改变变压器D侧的TA配置，无需测量绕组电流，直接利用D侧线电流，在分相列写回路方程的基础上，消去D侧绕组环流的影响，利用最小二乘法识别漏感，解决了Y/D接线方式下三相变压器的漏感计算问题。讨论了T型等效电路模型中漏感参数的可辩识性和算法的误差，指出只有在系统处于暂态过程中，才可以有效地对漏感参数进行辩识。给出了一种提高识别算法准确性的改进方案，并对方案进行了验证。EMTP仿真结果表明，基于该算法能够正确识别各相的漏感，虽然由于模型误差可能会使结果存在偏差，但漏感的内部故障特征明显，可以用于构建超高压大容量变压器及220kV以下电力变压器的新型保护原理，具有良好的应用前景。

Algorithm to Identify Leakage Inductances of Power Transformer With Y-Delta Connection

Algorithm to calculate leakage inductances of power transformer is proposed. Based on equivalent circuit equation, leakage inductances of power transformer with Y-Delta connection are estimated by least square method using line currents of Delta side directly and eliminating internal currents of windings in Delta side. Discrimination of leakage inductances in equivalent circuit equation and error of the algorithm are discussed. Leakage inductances can be identified effectively only when power system is in transient processes. And improved algorithm is proposed to enhance recognition precision of leakage inductances. Algorithm accuracy is verified by EMTP simulation. Result shows that leakage inductances estimated by proposed algorithm can distinguish inter fault status of transformer from a normal service operating status of transformer, which can act as criterions of transformer protection and has good project application prospect in the field of transformer protection.