Method for reducing voltage sag depth and duration by determining single-phase reclosing time sequence

A single-phase reclosing and voltage sag technology, applied in the direction of AC network voltage adjustment, electrical components, circuit devices, etc., can solve the problems of not considering the timing sequence, the lack of coordination between the reclosing on both sides of the line, etc., to reduce the loss. Effect

Active Publication Date: 2018-10-23
XIAN UNIV OF TECH
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  • Claims
  • Application Information

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Problems solved by technology

The traditional single-phase recloser does not consider the sequence, that is, there is no coordination relationship between the reclosers on both sides of the line

Method used

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  • Method for reducing voltage sag depth and duration by determining single-phase reclosing time sequence
  • Method for reducing voltage sag depth and duration by determining single-phase reclosing time sequence
  • Method for reducing voltage sag depth and duration by determining single-phase reclosing time sequence

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Embodiment Construction

[0027] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0028] The present invention proposes a method for reducing the depth and duration of voltage sags through the single-phase reclosing sequence, according to the network frame information and operating data, and using the concept of fault components to establish a fault additional state network, such as figure 1 As shown in , respectively calculate the voltage sag value of the sensitive load when different sides of each line coincide with a permanent fault, and determine the side with a smaller voltage sag value as the side of the line that overlaps first, and the other side as the side that overlaps later , to determine the single-phase reclosing sequence of each line in the power grid; for the rear reclosing side, use the first reclosing side of the line to reclose after the faulty phase circuit breaker, and whether the line voltage on the re...

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Abstract

The invention discloses a method for reducing the voltage sag depth and duration by determining a single-phase reclosing time sequence. According to grid rack information and operational data of a power grid, a voltage sag value of a sensitive load of each line is calculated when different sides of the line are overlapped with a permanent fault based on a fault component concept, one side of the smaller voltage sag value is determined to be a first overlapped side of the line and the other side is determined to be a second overlapped side, and single-phase reclosing time sequences of all linesin the power grid are determined; for the second overlapped sides, a condition of determining whether a fault phase line voltage of one second overlapped side is larger than a threshold after overlapping of the first overlapped sides of the lines with a fault-phase circuit breaker is used as a determination condition for opening reclosing; if the line voltage is larger than the threshold value, the second overlapped sides open the reclosing; and otherwise, the second overlapped sides locks the reclosing. The threshold value is set according to a largest line voltage on the condition of overlapping of the first overlapped sides with the permanent fault. Therefore, losses of the sensitive load are reduced on the condition of voltage sag when the overlapped side is overlapped with the permanent fault; and no investment needs to be added.

Description

technical field [0001] The invention belongs to the technical field of power systems and relates to a method for reducing the depth and duration of voltage sags through single-phase reclosing sequences. Background technique [0002] In recent years, voltage sag has become one of the main problems affecting the user's power quality, and its degree of harm is related to three characteristic quantities of sag depth, duration, and sag frequency. The causes of voltage sag include short-circuit fault, lightning strike, switch operation, switching of transformer and capacitor bank, etc. Short-circuit faults on transmission lines are the main cause of voltage sags. [0003] Most of the faults on the transmission line are single-phase ground faults, so the single-phase reclosing method has been widely used in our country. The traditional single-phase recloser does not consider the sequence, that is, there is no coordination relationship between the reclosers on both sides of the li...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H3/06H02H7/26H02J3/12
Inventor 梁振锋张清张惠智
Owner XIAN UNIV OF TECH
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