送端弱系统对特高压直流工程调试和运行的影响

特高压直流系统输送容量大、无功消耗大、控制复杂,而弱送端系统网架和电源构成简单,直流故障或扰动给电网运行控制带来诸多问题,分析特高压直流工程弱送端系统在电网安全稳定运行、直流启动与功率升降、过电压、机网协调等方面诸多问题,给出了相应的控制策略,并结合复奉特高压直流工程系统调试情况提出了弱送端系统特高压直流工程调试项目优化、电网运行方式和稳定控制措施、电压/无功控制、直流线路保护配置等方面需注意的问题及相应控制措施,同时分析了在特高压直流工程弱送端系统运行时的一些其他现象,文中结论对特高压直流工程规划、建设和运行具有一定的指导意义。

Impacts of Weak AC System on the Commissioning and Operation of UHVDC Transmission Project

Ultra-high voltage direct current(UHVDC ) system is characterized by large transmission capacity, high reactive power consumption and complex control system, while a weak AC sending system has much simple grid structure and power source composition. Consequently, the DC fault or disturbance can bring many problems to the power grid. An analysis is made on some problems of the weak AC system of UHVDC, such as safety and stabilization of power system, DC startup and power ramping & decreasing, overvoltage, and coordination between generators and power grid. Based on the commissioning of Xiang-Shang UHVDC project, some issues that needs to be addressed and corresponding controlling strategies are proposed for commissioning of UHVDC project with weak AC system, including optimization of commissioning items, operation mode of power system and stability control measures, voltage/reactive power control, and protection configuration of DC lines. Meanwhile, some other phenomena occuring during operation of the UHVDC with weak AC system are analyzed. The conclusions made in this paper can be a reference for planning, construction and operation of UHVDC project.