过负荷状态下保护与稳定控制协调策略

A Coordination Strategy Between Relay Protection and Stability Control Under Overload Conditions

"三道防线"中的继电保护与稳定控制之间缺乏协调配合为电网安全运行埋下隐患,为了协调二者之间的动作行为,从三方面进行了研究:改进了距离保护的动作特性,通过调整动作区和增加不平衡辅助判据提高了距离保护的耐过负荷能力;改进线路保护过负荷判据,利用线路温度替代电流来衡量线路的过负荷程度,利用线路热惯性延长过负荷下保护的动作时间,为安稳装置采取措施提供时间;提出了一种过负荷下继电保护与稳定控制的协调策略,通过设置区域保护实现继电保护与稳定控制之间的信息交换,及时采取控制措施,可以有效防止事故扩大,保证系统安全稳定运行。ADPSS仿真结果验证了该方案的正确性和有效性。

Lack of coordination among the relay protection and stability control in ＂three lines of defense＂ will create risk for power network safe operation. To coordinate relay protection and stability control, research work in three respects were done in this paper. Firstly, operation zones of distance protections were adjusted and unbalance auxiliary criterion was used to improve the characteristics of distance protection. Secondly, overload criterion of transmission lines were improved and temperatures of lines, instead of currents ,were used to measure overload degree. According to heat capacity of transmission lines, action time of backup protection was prolonged in overload condition. Thirdly, a control strategy coordinating relay protection and stability control were proposed through expanding protection functions. Through coordination control of relay protection and stability control, the cascading of the faults can be prevented. Advanced Digital Power System Simulator（ADPSS）simulation results verified the correctness and effectiveness of the proposed scheme.