百万千瓦级柔性直流接入大连电网后的系统特性分析

Analysis on System Characteristics After Incorporation of ±320 kV/1000 MW VSC-HVDC into Dalian Power Grid

基于电压源换流器和脉宽调制控制的柔性直流输电是一种新一代的高压直流输电技术,应用前景广阔。继上海南汇风电场柔性直流接入示范工程后,根据规划,2014年大连电网将投运世界上首个百万千瓦级柔性直流输电工程。为保障工程顺利实施,需详细分析大容量柔性直流接入对电网的影响。文中首先在国内广泛使用的电力系统机电暂态仿真程序中,开发了柔性直流输电系统模型与算法,并通过与电磁暂态计算的对比,验证了模型与算法的正确性。针对柔性直流接入后大连电网典型运行方式,研究了送受端交流电网故障以及直流控制方式和控制参数等对混联电网恢复特性的影响。研究结论为混联电网和交直流设备的安全稳定运行提供了技术支撑。

For their status of a new generation of HVDC transmission technology,the voltage source converter（VSC） and pulse width modulation（PWM） controlled-HVDC has wide application prospects.Following the Shanghai Nanhui wind farm accessing demonstration project,Dalian VSC-HVDC project with maximal transmission capacity will be put into operation in 2014.In order to ensure the successful implementation,a detailed analysis of the influence after VSC-HVDC incorporation is in order.In the environment of electromechanical transient simulation program widely applied in China,the model and algorithm of VSC-HVDC transmission system are developed and verified by comparing with the electromagnetic transient simulation calculation.In light of the typical operational mode of the hybrid system,the influence of AC grid fault at the sending and receiving end,DC control mode and different controller parameters on the recovery characteristics is studied.The conclusion provides a technical support for the secure and stable operation of VSC-HVDC transmission system and AC/DC equipment.