基于參數(shù)識別的小電流接地故障選線定位研究

 

劉哲¹，呂鵬²，孫建東²

（1 國網(wǎng)南京供電公司，江蘇 南京 210019；2 國電南瑞科技股份有限公司，江蘇 南京 210061）

 

    摘 要：針對小電流接地故障選線定位存在的難題，建立了基于線路集中參數(shù)下的單相接地故障零序等效模型，通過分析各線路電氣量特征，把其等效為電容模型，根據(jù)求解的線路對地電容值判斷是否為故障線路。同時建立故障線路數(shù)學(xué)模型，利用零序電壓、電流數(shù)據(jù)求解模型參數(shù)，依據(jù)所得參數(shù)計算故障點至母線的距離，從而實現(xiàn)接地點的精準(zhǔn)定位。經(jīng)RTDS故障仿真和MATLAB數(shù)據(jù)處理驗證該方法正確可靠，選線定位精度高，且不受中性點接地方式和不穩(wěn)定電弧的影響，有較強(qiáng)的耐過渡電阻能力，滿足集故障識別、選線和定位為一體的自動化要求。

    關(guān)鍵詞：小電流接地故障；單相接地故障；選線定位；電容模型；參數(shù)識別；區(qū)段定位

    中圖分類號：TM711；TM862     文獻(xiàn)標(biāo)識碼：A     文章編號：1007-3175(2018)08-0034-06

    Abstract: Aiming at the problem existing in the route selection location of small current neutral grounding fault, this paper established the single-phase grounding fault zero-sequence equivalent model. Through analysis of the electrical characteristics of each line, it was equaled to a capacitance model. Based on the solution circuit, the judgment of grounded capacitance value would be made on whether it was a fault line. At the same time the mathematical model of fault line was established. The model parameters for fault lines could be solved with the zero sequence voltage and current. Based on the parameters of the fault, the distance from the fault point to bus bar could be calculated to realize the accurate location of the fault.This principle has been verified via a RTDS simulator and MATLAB data processed tool. The method above has higher reliability and better capability of the fault resistance endurance, which is free from the impact of neutral grounding modes and unstable fault arc. Particularly, it can be combined with fault identification, fault line selection and fault location, which is satisfying the automated requirements.

    Key words: small current neutral grounding fault; single-phase earth fault; route selection location; capacitance model; parameter identification; zone location