Method and device for monitoring ground fault of overhead line

A ground fault and overhead line technology, applied in the field of distribution network systems, can solve the problems of increased possible fault points, inconvenient on-site use, and increased system cost, and achieve the effects of improving social production efficiency, improving work efficiency, and ensuring power supply security.

Inactive Publication Date: 2015-09-09
BEIJING HCRT ELECTRICAL EQUIP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the signal cabinet is located at the 10kv outlet or the connection between the substation and the grounding transformer neutral point; and new equipment is connected to the power system, resulting in an increase in system cost and possible failure points, which brings a lot of inconvenience to on-site use

Method used

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  • Method and device for monitoring ground fault of overhead line
  • Method and device for monitoring ground fault of overhead line
  • Method and device for monitoring ground fault of overhead line

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] figure 1 This is a flowchart of a method for monitoring ground faults of overhead lines provided by Embodiment 1 of the present invention. Such as figure 1 As shown, it mainly includes the following steps:

[0029] Step 11. Simultaneously measure the current increase vector of phase a, b and c in the three-phase current of the distribution network in the time period △t versus

[0030] For overhead lines of 10kV and above, when there is no fault in normal operation, the three-phase balance current vector diagram is as follows figure 2 Shown.

[0031] At time t, if there is no fault, the three phases (a, b, and c) are balanced, and the vector sum of the three-phase current can be expressed as: Ia ‾ ( t ) + Ib ‾ ( t ) + Ic ‾ ( t ) = 0 ;

[0032] When a ground fault occurs in the system, the three-phase balance current is broken, and the vector sum of the three-phase current is expressed as: among them, Is the zero sequen...

Embodiment 2

[0056] Figure 4 This is a schematic diagram of a device for monitoring ground faults of overhead lines provided in the second embodiment of the present invention. Such as Figure 4 As shown, mainly include:

[0057] The current increase vector measuring unit 41 is used to synchronously measure the current increase vector of phases a, b and c in the time period △t in the three-phase current of the distribution network versus

[0058] The ground fault judgment unit 42 is used to calculate the versus Vector sum If If the threshold is set, the three-phase current is balanced, and it is determined that the current line has no ground fault; otherwise, the three-phase current is unbalanced, and it is determined that a ground fault occurs.

[0059] The ground fault judgment unit calculates the versus Vector sum Realized by the vector sum formula construction unit, and the vector sum formula construction unit is specifically used to increase the vector according to the current vers...

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Abstract

The invention discloses a method and a device for monitoring ground faults of an overhead wire. The method includes synchronously measuring an incremental vector of current within a time period Delta t of each of a current phase a, a current phase b and a current phase c of a distribution network, computing the sum of the vectors, determining that the three current phases are balanced if the sum of the vectors is a set threshold value, and determining that a current circuit does not have a ground fault; and determining that the three current phases are imbalanced if the sum of the vectors is not the set threshold value, and determining that the current circuit has a ground fault. The method and the device have the advantage that the ground fault judgment accuracy is improved.

Description

Technical field [0001] The invention relates to the field of power distribution network systems, in particular to a method and device for monitoring ground faults of overhead lines. Background technique [0002] The automation and intelligence of the distribution network is the current development direction at home and abroad. my country has invested a lot in this area in recent years. Each year, the State Grid and China Southern Power Grid bid more than 10 billion yuan on products on the distribution network. Among them, the intelligent products of overhead line distribution network occupy a considerable proportion. Overhead lines are in the field, with long distances and complex environments. Faults (short circuit and grounding) are difficult to quickly locate the fault point, which brings greater difficulties to line maintenance personnel. This is especially reflected in mountain line maintenance personnel. [0003] It is relatively easy to determine the short-circuit fault of ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R31/08
CPCY04S10/522Y04S10/52
Inventor 顾涛李永段友涛王敬伟赵立永
Owner BEIJING HCRT ELECTRICAL EQUIP
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