含逆变型分布式电源外电网的短路计算等值及其影响因素分析  

Short-circuit Calculation Equivalent of External Power Grid Including Inverter Interfaced Distributed Generator and Analysis of Influencing Factors

作　　者：谢德兴 肖仕武 XIE Dexing;XIAO Shiwu(State Key Laboratory of Alternate Electrical Power System With Renewable Energy Sources(North China Electric Power University),Changping District,Beijing 102206,China)

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学),北京市昌平区102206

出　　处：《电网技术》2024年第7期2967-2976,I0096,共11页Power System Technology

基　　金：国网冀北公司项目“适应高比例分布式新能源接入的高可靠配电网故障处置关键技术研究与应用”(52018K230001)。

摘　　要：大量逆变型分布式电源接入会对电网短路电流计算及电网等值产生影响。该文提出了含逆变型分布式电源外电网的多端口戴维南等值方法,分析了等值参数的影响因素。首先,基于多端口电网络理论推导了外电网等值多端口的戴维南等值电路模型和参数表达式,分布式电源对等值电路的影响主要体现在开路等效电压。其次,根据开路电压计算公式,分析了分布式电源对开路等效电压的影响因素和规律。电网故障期间分布式电源可等效为压控电流源,其输出电流受独立电压源、等值端口电压及分布式电源低穿控制策略等的影响。然后,分析了等值端口电压、分布式电源容量、独立交流电源强弱对等效开路电压的影响规律,得到了等效开路电压随端口电压、分布式电源容量和外部电源内阻抗的变化曲线。通过IEEE33节点电网和某220kV高压电网仿真验证了等值方法和影响因素分析的正确性。Integrating many inverter-interfaced distributed generators(IIDG)will impact the power system's calculation of short-circuit current and grid equivalence.This paper proposes a multi-port Thevenin equivalent method for an external grid with a distributed generator,and the influencing factors of equivalent parameters are analyzed.Firstly,the Thevenin equivalent circuit model and parameter expression are derived based on the theory of multi-port electrical networks.The influence of distributed generators on equivalent circuits is mainly reflected in the open-circuit equivalent voltage.Secondly,according to the formula of open circuit voltage calculation,distributed generators'influence factors and rules on open circuit equivalent voltage are analyzed.The distributed generator can be equivalent to the voltage-controlled current source,and its output current is affected by the independent voltage source,the equivalent port voltage,and the low pass control strategy of the distributed generator.Then,the effect of equivalent port voltage,the capacity of the distributed generator,and the strength of independent AC power supply on equivalent open circuit voltage is analyzed,and the variation curve of equivalent open circuit voltage with port voltage,the capacity of the distributed generator,and internal impedance of external power supply is obtained.The simulation results of the IEEE33-node power grid and 220kV high-voltage power grid verify the correctness of the equivalence method and the analysis of influencing factors.

关 键 词：多端口戴维南等值 逆变型分布式电源 短路电流计算 

分 类 号：TM721[电气工程—电力系统及自动化]