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CN-122017448-A - Self-adaptive return coefficient method for grounding line selection

CN122017448ACN 122017448 ACN122017448 ACN 122017448ACN-122017448-A

Abstract

The invention discloses a self-adaptive return coefficient method for grounding line selection, which comprises the steps of obtaining three-phase current of a system when a single-phase grounding fault occurs in a small-current grounding power system, and calculating the minimum fixed value of phase current abrupt quantity according to the three-phase current Acquiring preset setting return coefficient And a phase current abrupt amount first threshold Second threshold value of phase current abrupt quantity Third threshold value of phase current abrupt quantity Wherein < < Calculating the adaptive return coefficient limit value curve variable According to the return coefficient of practical application The invention obtains the actual application return coefficient k ́, thus obtaining the action return value, the action return value is equal to the setting action value multiplied by the actual application return coefficient, and the problem that the return coefficient cannot return after the single-phase ground fault disappears or the problem that the return coefficient fails to correspond and returns in advance after the single-phase ground fault disappears is solved.

Inventors

  • HAO LIPING
  • DU JUAN
  • LI ZHIYU
  • LAN HAI
  • LIU YUANMIN
  • Mou nan
  • KOU JIN
  • ZHANG LIBO
  • GAO DAN
  • WANG CHAO
  • YUAN JINMING
  • ZHOU ZHONGQIANG
  • YANG QIANG
  • YAN HONGJUN
  • ZHANG XIANGXIONG
  • TAN YANYI
  • TAO YONGWEI
  • Pi Dinggui
  • TIAN YU
  • WANG LEI
  • ZHOU BING
  • FU TONGFU

Assignees

  • 贵州电网有限责任公司

Dates

Publication Date
20260512
Application Date
20251219

Claims (10)

  1. 1. The self-adaptive return coefficient method for the grounding line selection is characterized by comprising the steps of obtaining three-phase current of a system when a single-phase grounding fault occurs in a small-current grounding power system, and calculating the minimum fixed value of the phase current abrupt quantity according to the three-phase current Acquiring preset setting return coefficient And a phase current abrupt amount first threshold Second threshold value of phase current abrupt quantity Third threshold value of phase current abrupt quantity Wherein Calculating the adaptive return coefficient limit value curve variable And minimizing the phase current mutation A third threshold value corresponding to the phase current abrupt change Comparing to determine the return coefficient of practical application According to the return coefficient of the practical application And calculating an action return value with the tuning action value.
  2. 2. The method for adaptively selecting a return coefficient according to the ground characteristic of claim 1, wherein said phase current abrupt change amount is a minimum constant value The first threshold value A second threshold value A third threshold value Calculating the adaptive return coefficient limit value curve variable Combining the adaptive return coefficient limit value curve variable With the tuning return coefficient Determining the return coefficient of actual application 。
  3. 3. The method for adaptively selecting a return coefficient for ground connection according to claim 2, wherein said determining a return coefficient for actual use Comprises the steps of when the phase current is at a minimum value Less than or equal to a third threshold value of the phase current abrupt amount If the self-adaptive return coefficient limit value curve variable Less than or equal to the tuning return coefficient Determining the return coefficient of the actual application For setting the return coefficient If the adaptive return coefficient limit value curve variable Greater than the tuning return coefficient Determining the return coefficient of the actual application For said adaptive return coefficient limit curve variable 。
  4. 4. The method for adaptively selecting a return coefficient for a ground connection as set forth in claim 3, wherein said return coefficient is defined as a ratio of an action return value to an action constant value.
  5. 5. The method for adaptively selecting a return coefficient for ground connection as set forth in claim 4, wherein said determining a return coefficient for actual use The step of (a) further comprises, when the phase current is at a minimum value Greater than a third threshold of the phase current abrupt amount If the self-adaptive return coefficient limit value curve variable Greater than or equal to the tuning return coefficient Determining the return coefficient of the actual application For setting the return coefficient If the adaptive return coefficient limit value curve variable Less than the tuning return coefficient Determining the return coefficient of the actual application For said adaptive return coefficient limit curve variable 。
  6. 6. The method for adaptively returning the coefficient of ground selection as set forth in claim 5, wherein said action return value is calculated by the formula: 。
  7. 7. The method for adaptively selecting a return coefficient for a ground connection according to claim 6, wherein said phase current step amount is a minimum constant value The method comprises the steps of obtaining three-phase current according to a preset period, calculating phase current abrupt change of the three-phase current in real time, and selecting the minimum value in the three-phase current abrupt change as the minimum fixed value of the phase current abrupt change 。
  8. 8. The method of claim 7, wherein the adaptive return coefficient limit curve variable is denoted as y, the minimum phase current abrupt change value is denoted as x, a preset correspondence exists between y and x, and the correspondence is represented by a limit curve.
  9. 9. The method for adaptively selecting a return coefficient for a ground connection according to claim 8, wherein said adaptive return coefficient limit curve variable Based on the minimum value of the phase current abrupt change A first threshold value corresponding to the phase current abrupt change A second threshold value A third threshold value Is calculated by a piecewise functional relation or a linear interpolation relation.
  10. 10. The method for adaptively selecting a return coefficient for a ground connection according to claim 9, wherein said phase current abrupt change is calculated by a difference between a real-time sampling value of a three-phase current and a pre-fault reference value.

Description

Self-adaptive return coefficient method for grounding line selection Technical Field The invention relates to the technical field of grounding line selection, in particular to a self-adaptive return coefficient method for grounding line selection. Background The small-current grounding power system has single-phase grounding faults, the fault types are quite rich, and the grounding current span is quite large and is from tens of milliamperes to nearly kiloamperes. The fixed action return coefficient of the small-current grounding power system is set in the small-current grounding power system, so that the actual requirement cannot be met, the situations of small action fixed value, high-resistance single-phase grounding fault and load are set, the return coefficient is low and cannot return, or the situations of large action fixed value, high-resistance single-phase grounding fault and load are set, and the return coefficient is high and returns in advance. The return coefficient is the ratio of the action return value to the action constant value. Based on this, a small current ground line selection adaptive return coefficient method is required. Disclosure of Invention Therefore, the invention aims to solve the technical problem that a small-current grounding line selection self-adaptive return coefficient method is needed. The technical problem is solved by the following technical scheme that the invention provides a self-adaptive return coefficient method for grounding line selection, which comprises the steps of obtaining three-phase current of a system when a single-phase grounding fault occurs in a low-current grounding power system, and calculating the minimum fixed value of the phase current abrupt quantity according to the three-phase currentAcquiring preset setting return coefficientAnd a phase current abrupt amount first thresholdSecond threshold value of phase current abrupt quantityThird threshold value of phase current abrupt quantityWhereinCalculating the adaptive return coefficient limit value curve variableAnd minimizing the phase current mutationA third threshold value corresponding to the phase current abrupt changeComparing to determine the return coefficient of practical applicationAccording to the return coefficient of the practical applicationAnd calculating an action return value with the tuning action value. In a preferred embodiment of the adaptive return coefficient method for selecting a ground line according to the present invention, the phase current abrupt change amount minimum constant valueThe first threshold valueA second threshold valueA third threshold valueCalculating the adaptive return coefficient limit value curve variableCombining the adaptive return coefficient limit value curve variableWith the tuning return coefficientDetermining the return coefficient of actual application。 In a preferred embodiment of the adaptive return coefficient method for selecting a ground line of the present invention, the determining of the return coefficient for practical useComprises the steps of when the phase current is at a minimum valueLess than or equal to a third threshold value of the phase current abrupt amountIf the self-adaptive return coefficient limit value curve variableLess than or equal to the tuning return coefficientDetermining the return coefficient of the actual applicationFor setting the return coefficientIf the adaptive return coefficient limit value curve variableGreater than the tuning return coefficientDetermining the return coefficient of the actual applicationFor said adaptive return coefficient limit curve variable。 The return coefficient is defined as the ratio of the action return value to the action constant value. In a preferred embodiment of the adaptive return coefficient method for selecting a ground line of the present invention, the determining of the return coefficient for practical useThe step of (a) further comprises, when the phase current is at a minimum valueGreater than a third threshold of the phase current abrupt amountIf the self-adaptive return coefficient limit value curve variableGreater than or equal to the tuning return coefficientDetermining the return coefficient of the actual applicationFor setting the return coefficientIf the adaptive return coefficient limit value curve variableLess than the tuning return coefficientDetermining the return coefficient of the actual applicationFor said adaptive return coefficient limit curve variable。 In a preferred embodiment of the adaptive return coefficient method for ground selection of the present invention, the calculation formula of the action return value is:。 in a preferred embodiment of the adaptive return coefficient method for selecting a ground line of the present invention, the phase current abrupt change amount minimum constant value The method comprises the steps of obtaining three-phase current according to a preset period, calculating phase current abrupt change of the three-phas