新能源同步机对新能源多场站短路比的提升作用

Research on Improving Multiple Renewable Energy Stations Short Circuit Ratio by Motor-generator Pair

短路比作为衡量电力系统静态电压稳定的指标,被广泛应用于高压直流输电和新能源多场站系统的研究中。基于新能源多场站短路比的定义,研究新能源同步机(motor-generator pair,MGP)对新能源多场站短路比的提升作用。首先介绍了MGP系统的基本结构和独特优势,分析了新能源采用MGP并网对系统短路容量的提升作用。然后基于戴维南等值法和支路追加法分别分析了MGP对系统结构和节点阻抗矩阵的影响作用,揭示了MGP对短路比的影响机理,理论推导结果表明MGP能够提升系统的短路比。最后在PSCAD仿真软件中搭建了新能源三场站系统的仿真模型,结合算例的理论计算和仿真结果验证了MGP系统对新能源多场站短路比提升作用,并通过仿真验证了MGP对暂态低电压和暂态过电压的抑制作用。

As an index to measure the static voltage stability of power system,short circuit ratio is widely used in studying HVDC transmission system and multiple renewable energy stations.Based on the definition of multiple renewable energy stations short circuit ratio(MRSCR),the effect of motor-generator pair(MGP)on MRSCR is studied.Firstly,we introduced the basic structure and characteristics of MGP and analyzed the promotion effect of MGP on the short-circuit capacity of the system.Based on Thevenin equivalent method and branch addition method,the influence of MGP on system structure and node impedance matrix were analyzed respectively.The influence mechanism of MGP on short circuit ratio is revealed.The theoretical derivation result shows that MGP can improve the short circuit ratio of the system.Finally,simulation model of three renewable energy stations was built in PSCAD simulation software.Combined with the theoretical calculation result of an example and simulation result,the effect of MGP system on MRSCR is verified.Furthermore,it is verified by simulation that MGP can restrain transient low voltage and transient overvoltage.