CAJ | 학술논문

云广直流送端孤岛运行方式下发生直流闭锁时，系统将产生很高的工频过电压，是孤岛运行控制的关键问题。扰动后电压动态过程可分为不同阶段，文中分析了不同阶段影响过电压水平的主要因素。扰动后数百毫秒后的第2阶段电压虽然低于第1阶段，但持续时间较长，电压控制的要求更高，而且受发电机励磁控制的影响显著。短路比和过电压水平密切相关，提出了分阶段短路比的概念。发电机高压侧电压控制通过减小发电机侧恒定电压源和系统之间的电气距离，增大扰动后第2阶段的短路比，抑制过电压，并保证正常运行时合理的电压水平和无功分配。仿真结果验证了高压侧电压控制抑制过电压的效果。
운엄직류송단고도운행방식하발생직류폐쇄시，계통장산생흔고적공빈과전압，시고도운행공제적관건문제。우동후전압동태과정가분위불동계단，문중분석료불동계단영향과전압수평적주요인소。우동후수백호초후적제2계단전압수연저우제1계단，단지속시간교장，전압공제적요구경고，이차수발전궤려자공제적영향현저。단로비화과전압수평밀절상관，제출료분계단단로비적개념。발전궤고압측전압공제통과감소발전궤측항정전압원화계통지간적전기거리，증대우동후제2계단적단로비，억제과전압，병보증정상운행시합리적전압수평화무공분배。방진결과험증료고압측전압공제억제과전압적효과。
High amplitude overvoltage will occur in the AC system after the DC block in the islanded operation mode of Yunnan-Guangdong ultra-high voltage direct current UHVDC sending system.This is a key problem of islanded operation.The dynamic process of voltage can be divided into several phases.This paper analyzes the major factors influencing the overvoltage level in different phases.The overvoltage in hundreds of milliseconds after disturbance in phase two is lower than that of phase one,but the duration is longer and the criterion of voltage is higher.The voltage level of this phase is notably affected by excitation control of generators.The short-circuit ratio is closely related to the overvoltage level and the short-circuit ratio differs from phase to phase.The voltage control of the generator high-voltage-side increases the short-circuit ratio of phase two after disturbance and mitigates the overvoltage by reducing the electrical distance between the constant voltage source and the system.The rational voltage level and reactive power distribution in normal operation is guaranteed.The effectiveness of the high-voltage-side voltage control is verified by simulation results.