新能源场站分布式同步调相机暂态功角稳定性影响因素分析

Analysis of Influence Factors for Transient Rotor-angle Stability of Distributed Synchronous Condensers in Renewable Energy Stations

针对新能源场站同步调相机的暂态稳定性问题,分析其影响因素并揭示其影响机理,是研究稳定控制方案、提升稳定能力的关键。基于新能源送出通道发生单相故障后非全相运行的典型场景,采用等面积准则分析了电气距离、同步调相机惯量和新能源控制策略等关键因素对同步调相机暂态稳定性的影响,并在某新能源送出系统、含新能源和调相机的IEEE 39节点修改系统中进行了仿真验证。结果表明,新能源功率大规模、长距离输送,以及采用深度低电压穿越控制策略会对调相机的暂态功角稳定性产生不利影响;调相机惯量越大,其暂态功角稳定性越强;随着新能源有功出力恢复速率的减小,调相机功角稳定性呈现先降低后提升的趋势。此外,通过比较不同约束下新能源功率送出极限可知,增设同步调相机可以显著提升以电压安全或短路比为约束的新能源功率送出极限,但调相机功角稳定性约束也将成为限制新能源送出能力进一步提升的新瓶颈。

Regarding the transient stability problems of synchronous condensers(SCs) in renewable energy stations,analyzing the influence factors and revealing the influence mechanisms are the keys for studying the stability control schemes and improving stability capabilities.Based on the typical open-phase operation scenario after a single-phase fault occurs on a renewable energy transmission line,the influence of key factors including electrical distance,SC inertia,and the control strategy of renewable energy on SC transient stability is analyzed by adopting the equal area criterion.Simulation verification is conducted on the equivalent system of a renewable energy sending-end system and the modified IEEE 39-bus system with renewable energy and SCs.The results indicate that the large-scale and long-distance transmission of renewable energy and the deep low voltage ride-through(LVRT) control strategy have adverse effects on the rotor-angle stability of SCs,and the transient stability is stronger with the larger inertia of SCs.As the active power recovery rate of renewable energy decreases,the rotor-angle stability of SC shows a trend of decreasing first and then increasing.In addition,by comparing the power delivery limits of renewable energy under different constraints,it is known that adding SCs can significantly improve the power delivery limits of renewable energy constrained by voltage safety or short-circuit ratio.However,the rotor-angle stability constraint caused by SCs will also become a new bottleneck that limits the further improvement of power delivery capacity of renewable energy.