基于多线圈耦合的变压器数学模型及其应用

A Transformer Model Based on Coupling Multi-windings and Its Application Research

在常用的电力系统稳态故障分析软件中,变压器模型通常按绕组接线组别、中性点接地方式分正序、负序和零序分别给出,造成系统零序网络阻抗参数和正负序不同,因而对多重故障和特殊故障的分析变得困难。而对变压器内部故障,人们通常避免分析,以免除极其繁杂的运算。该文构建了一种用节点导纳阵描述的多线圈耦合的变压器数学模型。它无需区别三序网络,能方便地与用序分量描述的其它系统元件接口,有利于实现电力系统稳态故障分析软件的模块化。该模型在提高计算精度的前提下大大减少了变压器外部故障的计算量,对变压器内部故障,文中也提出了基于该模型的近似算法。在需要对电力网络中任意位置的故障进行仿真计算的软件中,该算法由于编程简单、精度较高而有广阔的应用前景。

In commonly used analysis software of steady-state faulted power system, transformer model, which gives the impedance of positive, negative, zero sequence according to its connection difference and whether the neutral point is grounded, causes the impedance of zero sequence networks be different from the positive and negative networks. So it becomes extremely difficult to analysis the lapped fault and specialized fault. Also, people always abandon the inspection of fault inside the transformer to avoid the most complicated computation. A coupling multi-windings-based transformer model with nodal admittance matrix is proposed, which does not have to treat the three sequence networks respectively and can readily describe the interfaces between transformer and other component of power system in sequential model. This new model is useful to accomplish the modulation of analyses software of steady-state faulted power system and cut sharply off the workload of calculation with improved count accuracy if the fault occurs outside the transformer. This paper also gives the approximate algorithm when transformers have a inner fault. In analysis software which simulates fault occur anywhere in power system networks, the algorithm proposed will have extensively application due to the simple programming and relatively high accuracy.