Unlock instant, AI-driven research and patent intelligence for your innovation.

Flexible DC power grid grounding fault line selection method and system

A ground fault, flexible direct current technology, applied in the direction of fault location, current/voltage measurement, information technology support system, etc., can solve the problems of branch circuit power failure, small short-circuit current, branch circuit short-term power failure, etc., to ensure safe and reliable operation , The effect of reliability improvement

Pending Publication Date: 2022-08-05
STATE GRID SHANDONG ELECTRIC POWER +1
View PDF0 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The current specific diagnosis method: if the AC side of the flexible DC power distribution system adopts high-impedance grounding, no other grounding measures are required on the DC side. However, the short-circuit current is very small. The traditional method usually uses disconnecting each branch one by one to find the grounding branch. Such a search method will cause a short-term power failure of the branch being tested
[0006] The problem in the above-mentioned prior art is that the traditional search method will cause a short-term power failure in the branch circuit of the test pull.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Flexible DC power grid grounding fault line selection method and system
  • Flexible DC power grid grounding fault line selection method and system

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] This embodiment discloses a system for selecting ground fault lines in a flexible DC power grid. figure 1 As shown, several branches of the flexible DC power grid, including the power supply branch and the load branch, are connected to the busbar. The primary side of the voltage sensor is connected to the positive and negative DC busbars and grounding, and the secondary side of the voltage sensor is connected to the analog quantity acquisition module of the relay protection device; a current sensor is installed on the positive and negative electrodes of the DC branch, and the secondary side of the current sensor is connected To the analog acquisition module of the relay protection device; the protection device can sample the positive voltage u of the bus bar p , negative voltage u n , the positive current i of each DC branch ip , negative current i in , the bus common mode voltage u com =(u p +u n ) / 2, the common mode current i of each branch icom =i ip +i in ....

Embodiment 2

[0045] The purpose of this embodiment is to provide a method for selecting a ground fault line of a flexible DC power grid, including:

[0046] Monitor the busbar common-mode voltage and the common-mode active power of each branch separately; the DC common-mode voltage of the busbar is U com0 , whose absolute value is |U com0 |, the third harmonic common mode power of each branch is obtained through measurement and calculation, and the third harmonic common mode active power of the i-th branch is set as P icom3 , when a ground fault occurs in the flexible DC power grid, the following criteria can be used to diagnose which line has a ground fault:

[0047] Criterion: If there is a DC common-mode voltage offset on the DC bus, that is: |U com0 |>k·U dc , if the third harmonic common mode active power on the jth branch is large and the direction is the outflow bus, that is: P jcom3 >ε, 1≤j≤n, it is determined that the DC branch j is faulty.

[0048] Among them: k is the overv...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention provides a flexible DC power grid grounding fault line selection method and system, and the method comprises the steps: monitoring a bus common-mode voltage and the common-mode active power of each branch, obtaining a DC common-mode voltage of a bus through measurement and calculation, and obtaining the third harmonic common-mode power of each branch through measurement and calculation; and when a grounding fault occurs in the flexible direct current power grid, if direct current common-mode voltage bias occurs in the direct current bus, third harmonic common-mode active power on the jth branch is relatively high and the direction is an outflow bus, judging that the direct current branch j has a fault. After a grounding fault branch is diagnosed, a signal is sent to inform a control system to cut off the DC branch, so that short-time power failure of other branches is avoided, and the operation reliability of a DC power grid is improved.

Description

technical field [0001] The invention belongs to the technical field of fault diagnosis of flexible direct current power grids, and in particular relates to a method and system for selecting ground fault lines of flexible direct current power grids. Background technique [0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art. [0003] For the DC side ungrounded flexible DC power grid composed of one bus, two or more AC / DC power supply branches and several load branches, during fault detection, it is generally used to disconnect each branch one by one to find the grounded branch. Such a search method will cause a short-term power failure of the branch that is being pulled. [0004] Two or more AC / DC power supply branches are suitable for power supply of important loads. It is necessary to accurately remove the fault in a short time without causing the non-faulty line to lose po...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/52G01R31/08G01R19/00G01R21/00
CPCG01R31/086G01R31/52G01R19/0084G01R21/002Y04S10/52Y02E60/60
Inventor 秦文康徐习东李峰王洋王黎孙振海牟磊孙伟涛马晓路宋彦臻彭寅文宏成
Owner STATE GRID SHANDONG ELECTRIC POWER