Single-phase-to-ground fault line selection method for ring neutral point ungrounded distribution network
A single-phase ground fault, neutral point ungrounded technology, applied in the direction of fault location, fault detection according to conductor type, information technology support system, etc., to achieve the effect of improving safety and reliability and being widely applicable
Inactive Publication Date: 2019-06-14
CHINA UNIV OF MINING & TECH
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Problems solved by technology
[0004] In order to solve the technical problems raised by the above-mentioned background technology, the present invention aims to provide a single-phase ground fault line selection method for the ring-shaped neutral point ungrounded distribution network, overcome the shortcomings of the traditional single-phase ground fault line selection of the distribution network, and realize the Single-phase-to-earth fault line selection for neutral point ungrounded distribution network
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[0028] The technical solutions of the present invention will be described in detail below in conjunction with the accompanying drawings.
[0029] The present invention proposes a single-phase ground fault line selection method for a ring-shaped neutral point ungrounded distribution network, such as figure 1 As shown, the specific steps are as follows.
[0030] Step 1: Set the line attributes according to the structure of the ring distribution network. Determine whether each line is a ring line or a feeder, and number it; determine the substation to which the feeder belongs, and number the feeder in each substation. It is stipulated that the direction of capacitive zero-sequence current is positive when it flows from the busbar to the line, and negative when it flows from the line to the busbar.
[0031] Step 2: Determine whether a single-phase ground fault occurs by detecting the magnitude of the zero-sequence voltage, and if so, start fault line selection.
[0032] When U ...
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The invention discloses a single-phase grounding fault line selection method of a ring neutral point-ungrounded power distribution network. According to the method of the invention, whether a single-phase grounding fault occurs is judged through detecting the zero-sequence voltage of the ring neutral point-ungrounded power distribution network; when the single-phase grounding fault occurs, the zero sequence current of each loop line and feeder line is detected; and whether a loop line malfunctions or a feeder line malfunctions can be distinguished according to the characteristics of the vector sum of the zero sequence current at two ends of each of all loop lines, if a loop line fault malfunctions, the malfunctioned loop line be judged through comparing the characteristics of the zero sequence vector sum of two sides of each of the loop lines, if a feeder line malfunctions, the malfunctioned feeder line be judged through comparing the directions of the zero sequence current of all feeder lines in each substation. With the single-phase grounding fault line selection method of the ring neutral point-ungrounded power distribution network of the invention adopted, the single-phase grounding fault line selection of the ring neutral point-ungrounded power distribution network is realized, and the safety and reliability of the operation of the ring neutral point-ungrounded power distribution network can be improved.
Description
technical field [0001] The invention belongs to the technical field of electric power system automation, and in particular relates to a single-phase ground fault line selection method of an annular neutral point ungrounded distribution network. Background technique [0002] Single-phase ground fault line selection in distribution network has always been a difficult point in relay protection. When a single-phase-to-ground fault occurs in the distribution network, the fault characteristics are complex, there are many types of faults, and the fault components are relatively small, which seriously affects the accuracy of ground fault line selection. For this reason, a large number of power workers have also proposed some line selection methods based on the characteristics of zero-sequence components after a ground fault. These line selection methods mainly include: the line selection method based on the zero-sequence current quantity composed of the characteristics of the zero-...
Claims
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IPC IPC(8): G01R31/08
CPCG01R31/086Y04S10/52
Inventor 陈奎叶智韫刘学超端祝超方永丽刘昊唐轶
Owner CHINA UNIV OF MINING & TECH