伪双极VSC-LCC型混合直流输电系统启动方法  

Startup Procedure for VSC-LCC Based Hybrid Pseudo Bipolar HVDC System

作　　者：余瑜[1,2] 刘开培[1] 陈灏泽 杨洁[1] 秦亮[1] 

机构地区：[1]武汉大学电气工程学院,武汉430072 [2]湖北工业大学电气与电子工程学院,武汉430068

出　　处：《高电压技术》2014年第8期2572-2578,共7页High Voltage Engineering

基　　金：国家自然科学基金(51207115)~~

摘　　要：为保障混合直流输电系统的顺利启动,推导了伪双极VSC-LCC型混合高压直流输电系统的数学模型,并设计了该系统中整流侧VSC和逆变侧LCC之间的协同控制策略。提出了3阶段式启动方案:第1阶段系统串联限流电阻通过VSC反并联二极管做不控整流建立直流侧电压;第2阶段启动VSC采用定直流电压控制,继续充电使得直流电压达到预设值;第3阶段退出限流电阻并启动LCC做定直流电流控制,电流控制量由零逐渐增至设定值,启动过程完成。最后在PSCAD/EMTDC中建立了伪双极VSC-LCC型混合直流输电系统的主电路和控制电路模型进行仿真,结果证明提出的启动控制方案是合理的。整个启动过程在1.5 s内完成,启动过程中无论是电流还是电压均未出现明显过冲现象;关断角的测量显示启功过程逆变侧LCC未发生逆变失败;启动完成后直流电压稳定在设定值400 kV,直流电流稳定在设定值1.0 kA,送端、受端有功功率则稳定在400 MW,系统能准确跟踪目标参考值稳定运行。In order to secure the successful start-up of HB-HVDC system, we established a numerical model of VSC-LCC-based hybrid pseudo bipolar HVDC system and designed a coordination control strategy for the system＇s VSC at converter side and LCC at inverter side. Consequently, a three-step start-up procedure for the system is proposed as follows： 1） to lock both the VSC and LCC, to connect the current limit resistor in series, and to use the inverter parallel diodes of the VSC to charge the capacitance in the DC side by uncontrolled rectifier; 2） after the DC voltage reaches a given value, to unlock the VSC converter, and to use the DC voltage as the controlled variable to keep charging the capa- citance and raise the DC voltage; 3） when the DC voltage achieves to the instruction value, to cut off the resistor, to unlock the LCC inverter with the constant DC current control, and to complete the start-up procedure when the current in- struction reaches its rated value. Furthermore, we conducted simulation of the system using models of its main circuit and control circuit in PSCAD/EMTDC. The results indicate that the proposed steady-state control strategy and start-up strate- gy are effective. The entire start-up process is completed within 1.5 s, neither current nor voltage shows obvious overshoot. Measurement of closing angle indicates that no commutation failure occurs in the LCC inverter. After the start-up, the DC voltage, DC current and active power stay stable at 400 kV, 1.0 kA, and 400 MW respectively, while the system can track the target reference accurately and operate stably.

关 键 词：伪双极 常规直流输电 柔性直流输电 混合直流输电 控制策略 启动控制 

分 类 号：TM721.1[电气工程—电力系统及自动化]