A method for locating ground faults in small current systems
A ground fault and positioning method technology, which is applied in the direction of measuring current/voltage, measuring electricity, and measuring electrical variables, etc., can solve the problems of large data upload volume and low positioning reliability, so as to reduce communication pressure, high reliability, and upload The effect of data reduction
Active Publication Date: 2019-07-23
STATE GRID HUNAN ELECTRIC POWER +3
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[0005] In view of the defects of low positioning reliability and large amount of data uploaded in the existing small current fault location method, it is necessary to provide a small current system ground fault location method, which reduces the amount of data uploaded and the communication pressure of the data channel and improve positioning reliability
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[0051] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.
[0052] see figure 1 , a kind of small current system grounding fault localization method provided by the present invention, comprises the steps:
[0053] Step 1: Extract the zero-sequence current of each feeder terminal on the fault feeder before and after the fault moment;
[0054] Among them, the zero-sequence voltage of the bus is collected in real time. When the zero-sequence voltage of the bus is detected to exceed the fault discrimination threshold, the fault location algorithm is started. First, the fault feeder is determined according to the fault line selection method, and each of the M feeder terminals on the fault feeder is extracted. The zero-sequence current i of a feeder terminal in P power frequency cycles before the fault time and Q power frequency cycles after the fault time 0ab (n);
[0055] Among them, i 0ab (n) is expres...
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The invention discloses a method for locating a grounding fault in a small current system, which includes: extracting the zero-sequence current of each feeder terminal on the fault feeder before and after the fault moment; moving the data window point by point and calculating The eigenvalue of the zero-sequence current below; construct the eigenvalue curve of each feeder terminal; obtain the sampling point corresponding to the maximum eigenvalue in each eigenvalue curve of the feeder terminal closest to the bus on the fault feeder; obtain the characteristics of the remaining feeder terminals The eigenvalues corresponding to the same sampling points obtained above in the value curve; calculate the Euclidean distance of the eigenvalues of two adjacent feeder terminals; arrange the Euclidean distances from large to small and select the largest N Euclidean distances; if one If the Euclidean distance is greater than the sum of the remaining N‑1 Euclidean distances, the interval between the two feeder terminals corresponding to the Euclidean distance is the fault interval. Through the above method, the present invention can improve the reliability of fault location and reduce the communication pressure of the data channel.
Description
technical field [0001] The invention relates to the technical field of distribution network fault detection, in particular to a method for locating ground faults in small current systems. Background technique [0002] In our country, the distribution network area is widely distributed, the failure rate is high, and the protection configuration is relatively low. The medium-voltage distribution network is dominated by overhead lines, and the proportion of single-phase ground faults is large. Since the distribution network generally adopts the low-current grounding method, no short-circuit loop is formed when a single-phase ground fault occurs, and only a small fault is generated by the zero-sequence capacitance of the feeder. fault current, so that the system can still continue to run with faults for 1 to 2 hours. In order to avoid further expansion of the single-phase ground fault, it is necessary to find the ground fault point as soon as possible and eliminate the fault. ...
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IPC IPC(8): G01R31/02G01R19/165
Inventor 冷华刘鹏辉黄纯朱吉然张志丹唐海国龚汉阳刘海峰敖非李红青李秩期
Owner STATE GRID HUNAN ELECTRIC POWER