计及逆变型分布式电源的有源配电网单相接地故障分析

风电、光伏等可再生能源以逆变型分布式电源(IIDG)形式并网后,使配电网成为有源配电网,其接地故障分布特点与传统配电网不同。文章通过分析恒功率控制型和低电压穿越控制型IIDG故障电流特性,建立其故障等值模型,然后,针对不接地系统建立计及IIDG的单相接地故障分析模型,分析并网变压器中性点不同接地方式和IIDG的接入位置下,故障点电流以及IIDG至故障点间线路零序电流特征分布,最后,通过PSCAD/EMTDC建立含IIDG接入的配电网故障仿真模型,验证了单相接地故障建模及分析方法的有效性。

Analysis on single-phase earth fault of active distribution network containing inverter interfaced distributed generator

Renewable energy connected to the distribution network in the form of inverter interfaced distributed generator(IIDG)makes the distribution network become an active one.Fault characteristics of the active distribution network have changed significantly compared with the traditional distribution network.The fault equivalent model is established by analyzing the fault current characteristics of IIDG that adopts the constant power or low voltage ride through control strategy.Then,single-phase earth fault analysis model considering IIDG is established for the ungrounded system.The distribution characteristics of fault point current and zero sequence current of line section between IIDG and the fault point are analyzed under the different grounding modes of the grid-connected transformer and the different access positions of IIDG.Finally,simulation model of the active system with IIDG is constructed in PSCAD/EMTDC to verify the effectiveness of single-phase earth fault modelling and analysis method.