VSC系统换流变压器共模模型及主绝缘在线监测方法  

Common-mode Model and Method of Online Insulation Monitoring for Converter Transformer in Voltage Sourced Converter System

作　　者：陆格野 张品佳 LU Geye;ZHANG Pinjia(State Key Lab of Security Control and Simulation of Power Systems and Large Scale Generation Equipment(Department of Electrical Engineering,Tsinghua University),Haidian District,Beijing 100084,China)

机构地区：[1]电力系统及大型发电设备安全控制和仿真国家重点实验室(清华大学电机系),北京市海淀区100084

出　　处：《中国电机工程学报》2021年第11期3885-3895,共11页Proceedings of the CSEE

基　　金：国家自然科学基金优秀青年科学基金项目(51822705)。

摘　　要：绝缘老化是威胁换流变压器安全运行的重要隐患,传统的绝缘监测方法难以实现可靠的换流变预防性保护。电压源型换流器(voltage sourced converter,VSC)输出电压特征谐波分量,可用于在线监测连接换流变的主绝缘健康状况。首先,探究VSC系统共模特征谐波用于换流变绝缘监测的可行性与优势。其次,构建YN/yn绕组接线的换流变共模电路模型,给出表征共模电压分布和绝缘电参数关系的数学模型。然后,定义压比频率响应和阻抗频率响应,对比电路模型和数学模型,说明两者的等效性。在线实验结果验证基于VSC系统共模特征谐波监测换流变主绝缘老化的有效性。该所述方法具有如下优势:1)不改变系统原有拓扑结构,无需安装额外的测试设备;2)对监测状态量的分析方法简单直观;3)监测结果不受系统工况波动和高频干扰的影响。The reliability of converter transformers is threatened by insulation ageing. Voltage sourced converter(VSC) system has inherent common-mode characteristic harmonics, which facilitates non-invasive online insulation monitoring for the connected transformer. This paper firstly analyzed the advantages of common-mode characteristic harmonics in monitoring applications. Then, a common-mode circuit model was built and a mathematical model was developed to present the relationship between common-mode voltage distribution and equivalent insulation parameters. Next,a voltage-ratio frequency response and an impedance frequency response were defined. The equivalent of circuit model and mathematical model was verified. Online experimental results validate the effectiveness of the proposed insulation monitoring method based on two responses. The proposed method has the following advantages: 1) no need of changing system topology and adding extra test equipment;2) simple analysis for monitoring data;3) few influences from system operating fluctuation and high-frequency interferences.

关 键 词：电压源型换流器 变压器 模型 绝缘 在线监测 共模谐波 

分 类 号：TM464[电气工程—电器]