基于短时投入阻尼电阻技术的谐振接地系统故障选线方法

A Fault Line Selection Method of Resonance Grounded System Based on Short-Time Input Damping Resistance

谐振接地系统中,消弧线圈在补偿容性故障电流以提高供电可靠性的同时,也使故障选线变得更加困难。目前,基于主动注入信号的故障选线方法由于信号强度的可控性较差,这类方法没有得到广泛的应用。为此,文章提出可在系统一次侧注入信号的谐振接地故障选线方法。在系统发生单相接地短路后,通过短时投入预调式消弧线圈阻尼电阻产生选线信号以获得各条馈线的零序频率响应,基于故障与健全馈线零序频率响应相频特性的显著差异以及电流信号主要流经故障馈线的特点,建立故障选线判据。理论推导、仿真分析均验证了该方案能够快速准确地选取故障馈线,具备较好的故障过渡电阻耐受能力,并且在一定的信号噪声背景下依然有效。

In resonance grounding system,arc suppression coil compensates capacitive fault current to improve power supply reliability,but also makes fault line selection more difficult.The approach of fault line identification based on active injection signal has not been widely used due to the poor controllability of signal strength.For this reason,a fault line identification method of resonance grounding system is proposed,which can produce signals on the primary side of the system.A line identification signal is obtained in the damping resistance of the pre-regulating arc suppression coil for a short time,which can accurately obtain zero sequence frequency response of each feeder,when occurring the single-phase grounding faults.Fault line selection criteria are established based on the difference of frequency response characteristics of zero sequence frequency between fault and perfect feeders and the characteristics of current signal mainly flowing through fault feeders.Theoretical derivation,simulation analysis show that the scheme can select fault feeders quickly and accurately,which has good fault transition resistance tolerance ability,and is still effective under certain signal noise background.