风光火打捆交直流外送系统的高频切机方案研究

Studies on High-Frequency Generator Tripping Strategy for Wind-Photovoltaic-Thermal-Bundled Power Transmitted by AC/DC System

基于宁夏电网风光火打捆交直流外送典型输电模式,针对直流闭锁、省级电网与主网解列连锁故障发生后引起的省级电网高频问题,制定了适应风光波动的风光火联合高频切机方案。首先从机组响应扰动的整步、惯量及调速3个环节入手,分析了风光接入对系统动态频率特性的影响;其次,在风光零发方式下,基于"最小欠切原则",制定了适应不同故障类型的初始高频切机方案;进一步,在风光大发方式下,按"优先切风光"原则对初始高频切机方案进行轮次替代,制定了3种计及风光波动的风光火联合高频切机改进方案,并结合宁夏电网对所提改进方案进行了适应性分析。最后,采用风光出力腰发方式对改进方案进行了仿真验证。

Based on Ningxia wind-PV-thermal-bundled power transmitted with AC/DC system, and on highfrequency issue in the provincial grid caused by DC block and system separation cascading faults, wind-PV-thermal powerunited high-frequency generator tripping strategy adaptive to new fluctuant power is studied. Firstly, impacts of wind and PV power integration on system dynamic frequency characteristics are analyzed from generator’s three responding links of synchronizing, inertia and speed regulating. Secondly, under operation mode without wind or PV power, based on ＂principle of minimum lacking-tripping＂, an initial high-frequency generator tripping strategy adaptive to different faults is made. Furthermore, under operation mode with 60% wind and PV power, based on principles of ＂tripping new energy power first＂, initial generator tripping strategy is replaced by round, and three improved wind-PV-thermal power-united highfrequency generator tripping strategies adaptive to the fluctuant new energy power are proposed, whose adaptabilities are simulated in Ningxia Grid. Finally, under operation mode with 30% wind and PV power, the adaptabilities of the improved strategies are proved.