直流系统采用电容换相换流器技术的特性研究  

Study on Capacitor Commutated Converter Applied in HVDC Projects

作　　者：杨汾艳[1] 徐政[1] 

机构地区：[1]浙江大学电气工程学院,浙江省杭州市310027

出　　处：《中国电机工程学报》2008年第7期91-96,共6页Proceedings of the CSEE

基　　金："十一五"国家科技支撑计划重大项目(2006BAA02A21)~~

摘　　要：对直流输电采用电容换相换流器(capacitor com-mutated converter,CCC)技术时的系统特性进行了研究。导出了描述CCC结构直流系统稳态特性的数学模型,它由15个基本方程构成。采用数值计算方法对CCC结构直流系统的稳态数学模型进行详细的分析,并与电网换相换流器(line commutated converter,LCC)结构直流系统进行了比较,揭示了CCC结构直流系统的一些重要优势。推导出了CCC换流阀电压峰值的表达式,并在此基础上提出了选择换相电容值的方法,采用该方法所选择的换相电容值能充分发挥CCC结构直流系统的技术优势,但又不会过多增加阀的成本。采用仿真工具电磁暂态仿真程序PSCAD/EMTDC,以葛南直流单极输电系统为研究对象,交流系统发生单相对地短路故障为例,对CCC和LCC系统的暂态特性进行仿真比较,表明CCC结构直流系统具有较好的故障恢复特性。The system performance of a HVDC link applying CCC （capacitor comnautated converter） technology is studied. The mathematical model representing the CCC-HVDC system＇s steady-state characteristics is derived, which is composed of 15 basic equations. Then the steady-state mathematical model is analyzed in detail by means of numerical computation method, some important advantages of CCC-HVDC systems are revealed compared with that of LCC （line cornmutated converter） based HVDC system. The peak-value expression of the valve voltage is deduced, based on which a method to select the capacitance of the commutation capacitor is proposed. With the capacitance determined by this way, the technological superiority of CCC-HVDC system can be realized, and at the same time the valve cost is increased not too much. The transient responses of CCC- and LCC- HVDC system are simulated and compared, taking a single-phase AC fault as an example. The result shows that the CCC-HVDC system has better recovery characteristics. The simulation tool is PSCAD/EMTDC. The research object is Ge-Nan HVDC monopolar transmission project.

关 键 词：电容换相换流器 换相电容 稳态特性 暂态特性 直流输电 

分 类 号：TM76[电气工程—电力系统及自动化]