基于不对称低压穿越的逆变型电源的故障计算模型

Fault calculation model of inverter power supply based on asymmetric low-voltage ride through

新能源具有分布特性,使得新型电力系统易发生近电源故障,导致三相不对称,对逆变型电源的影响难以忽略。逆变型电源的传统正序模型只能对称地输出无功补偿,无法正确地计算新型电力系统的近电源不对称故障。基于此,首先指出现有低压穿越规范在三相不对称时存在的问题,并对其进行改进和完善,采用相电压指标设计了一套不对称低压穿越规范。然后,建立了逆变型电源的通用故障计算模型,并分别分析了其接入大电流和小电流接地系统时的等效方法,通过对单电源系统的仿真来验证模型的有效性。最后,提出了新型电力系统的相分量故障计算方法,推导了各故障类型和逆变型电源模型的代入计算方法。并通过算例验证了所提算法的正确性。

The distribution characteristics of new energy make it easy for near power failures to occur in new power systems,leading to it being difficult to ignore the impact of three-phase asymmetry on inverter power supply.The traditional positive sequence model for inverter power supply can only symmetrically output reactive power compensation.It cannot accurately calculate the near power asymmetric faults.First,this paper points out the problems of the existing low-voltage ride through specifications when three-phase asymmetry occurs.It improves them,and designs a set of asymmetric low-voltage ride through specifications using phase voltage indicators.Then,a universal fault calculation model for the inverter power supply is established,and its equivalent methods when connected to high current and low current grounding systems are analyzed respectively.The effectiveness of the model is verified through simulation of the single power supply system.Finally,the phase component fault calculation method for the new power system is proposed,and the substitution calculation methods for various fault types and inverter power supply model are derived.The correctness of the proposed algorithm is verified through numerical examples.This work is supported by the National Natural Science Foundation of China(No.52377172).