光伏接入对玉树电网安全稳定性影响及控制策略

Impact of PV integration on safety and stability of Yushu Grid and control strategy

结合玉树电网的实际运行情况,基于BPA软件建立了含光伏电站接入的机电暂态仿真模型,基于该模型研究了玉树电网与青海主网解列后的孤网暂态特性,指出玉树孤网的主要问题是频率稳定。采用关键断面故障仿真技术,分析了光伏电站出力和光伏接入地点对安全稳定控制策略的影响,提出了玉树孤网运行的安全稳定控制策略,建议玉树电网典型方式下不配置高频切机措施,主要由机组自身保护应对可能出现的高频问题,采用低频减负荷方案解决频率稳定问题,并通过仿真验证了控制策略的有效性。

According to the actual operational conditions of Yushu Grid,an electromechanical transient simulation model with PV station is built based on BPA software,with which,the transient characteristics of Yushu Grid isolated from Qinghai main grid is researched. It is found that the frequency stability is the main problem of isolated Yushu Grid. The key section fault simulation technology is applied to analyze the impact of the output power and access location of PV station on the strategy of safety and stability control,based on which,a control strategy is proposed for isolated Yushu Grid. It is suggested that,the unit protection,instead of the high-frequency tripping scheme,should be adopted to solve the high-frequency problem under its typical operation mode and the low-frequency load shedding scheme should be adopted to solve the frequency stability problem. The effectiveness of the proposed control strategy is verified by simulation.