特快速暂态过电压下特高压变压器绕组的建模算法研究

项目名称： 特快速暂态过电压下特高压变压器绕组的建模算法研究

项目编号： No.51207042

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 电气科学与工程学科

项目作者： 张萍

作者单位： 河北工业大学

项目金额： 26万元

中文摘要： 特快速暂态过电压(VFTO)上升时间为ns级、振荡频率高达MHZ，若侵入特高压电力变压器必将严重影响其绕组绝缘，国内外已发生多起击穿事故，但其研究尚处于起步阶段。本项目以特高压电力变压器绕组为研究对象，研究分为三步：1、引入自调节变焦弧阻等效隔离开关的电弧电阻，FNN离线计算分布电容以提高计算精度。2、提出时域+频域+散射参数的综合暂态算法：含频变阻抗用Lax和Weno差分法求解的时域算法；分析谐振及击穿绕组定位的暂态算法；基于理论推导+网络测试仪获取散射参数的算法，采用矢量匹配法和最优Pade算法降阶；考虑隔离开关的机械特性、击穿特性及多次重击穿过程对VFTO的影响，仿真计算采用自适应变步长求解。3、基于以上研究所得数据开发专门的仿真平台，用于计算VFTO作用下特高压电力变压器绕组的暂态过电压分布。本项目的研究成果将为绕组绝缘的低成本设计、优化与拓展应用提供重要的理论参考及工程实际作用。

中文关键词： 特快速暂态过电压；特高压电力变压器；建模；分布参数；有限元

英文摘要： Rising time of Very Fast Transient Over-voltage(VFTO) is up to ns and vibratory frequency of which is up to MHZ. If such steep voltage intrudes Ultra High-voltage(UHV) power transformer, insulation of windings may be seriously damaged. Some inland and overseas cases have been reported recently; related research is still in underway,especially about damage of VFTO on UHV transformer wingdings insulation. In this item, investigative object is UHV transformer windings and investigation is divided into three steps: firstly self-adjusted and various welding resistance is equaled as that of isolated switch and Fuzzy Neural Network is used to compute discrete capacitance off-line in order to improve computational precision; secondly synthetically transient time-domain-model+frequency domain model+S-paparmater model are established, that is, time-domain transient algorithm having time-varying impedance solved by difference method, frequency-domain model used to confirm vibrancy and orientation of already destroyed windings, distributed model based on s-parameters gotten by theoretical formula and equipment of network tester. The reduced models are based on vector fitting method and optimal Pade method. And in the case of mechanical and damage characteristics of isolated switch, and effect of multi-damage of VFTO on inso

英文关键词： VFTO；Ultra-high power transformer；model；distributed parameters；FEM