Zero-sequence current detection device and method for neutral point grounding system through small resistance

A technology of small resistance grounding and zero-sequence current, applied in the field of power system, can solve the problem of low sensitivity of differential protection action, achieve the effect of improving sensitivity, increasing sensitivity, and reducing starting current value

Active Publication Date: 2018-01-12
STATE GRID SHANDONG ELECTRIC POWER +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect of low sensitivity of differential protection action in the prior art

Method used

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  • Zero-sequence current detection device and method for neutral point grounding system through small resistance
  • Zero-sequence current detection device and method for neutral point grounding system through small resistance
  • Zero-sequence current detection device and method for neutral point grounding system through small resistance

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Embodiment 1

[0033] Such as figure 2 As shown, the neutral point grounding system through a small resistance includes the main transformer TR1, the grounding transformer TR2 and the resistor R0, the secondary side output line of the main transformer TR1 includes the main trunk line and at least two branch lines, and the secondary side includes the Δ side and the Y side ,For example, figure 2 The Δ-side output line of the secondary side of the main transformer TR1 includes a main line L1 and at least two branch lines L2 and L3. The high voltage side of the grounding transformer TR2 is connected to the first branch line L2, the low voltage side of the grounding transformer TR2 is connected to one end of the resistor R0, and the other end of the resistor R0 is grounded.

[0034] This embodiment provides a zero-sequence current detection device for a neutral point grounded system through a small resistance, such as figure 2 The shown neutral point is grounded by a small resistance, such a...

Embodiment 2

[0043] This embodiment provides a zero-sequence current detection method for a neutral point grounded system through a small resistance, for example, it is applied to the zero-sequence current detection device in the above-mentioned embodiment 1, such as Figure 5 As shown, the zero-sequence current detection method includes the following steps:

[0044] S1. Configure the primary side of the first current transformer CT1 on the primary side input wire of the main transformer TR1, configure the primary side of the second current transformer CT2 on the second branch line L3 of the main transformer TR1, and configure the primary side of the second current transformer CT2 on the main transformer TR1 The primary side of the third current transformer CT3 is arranged on the trunk line L1;

[0045] S2. Connect the secondary side of the first current transformer CT1 to the first current input end of the main transformer differential protection device 20;

[0046] S3, connecting the fi...

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Abstract

The invention discloses a zero sequence current detection device for a neutral point connected to a grounding system through a small resistor and a method. The zero sequence current detection device for a neutral point connected to a grounding system comprises a first current mutual inductor, a second current mutual inductor and a third current mutual inductor. The primary side of the first current mutual inductor is arranged on the primary side input lead of a main transformer; the secondary side of the first current mutual inductor is connected to a first current input terminal of a main transformer differential protection device; the primary side of the second current mutual inductor is configured on the second branch line of the main transformer; the primary side and the secondary side of the second current mutual inductor are connected to the primary side and the secondary side of the third current mutual inductor in parallel and are connected to the second current input terminal of the main transformer differential protection device; the second secondary side of the second current mutual inductor is connected to the third current input terminal of the main transformer differential protection device; the polarities of the first secondary side and the second secondary side which are connected to the main transformer differential protection device are opposite; and the primary side of the third current mutual inductor is configured on a main line of the main transformer. The invention is high in differential protection motion sensitivity and can improve safe and reliable operation capability of the small resistor grounding system.

Description

technical field [0001] The invention relates to the field of power systems, in particular to a zero-sequence current detection device and method for a neutral point grounded system through a small resistance. Background technique [0002] With the rapid development of social economy, line corridor resources are becoming increasingly scarce, the process of undergrounding overhead lines is gradually accelerating, and the proportion of cable lines is constantly increasing. The wide application of cables makes the capacitive current very high when the power grid has a single-phase ground fault, which can reach hundreds of amps or even thousands of amps. In view of this, a method of decentralized compensation using the neutral point of the main transformer to be grounded through the arc-suppression coil appeared earlier, but this method has exposed in actual operation that the number of arc-suppression coils needs to be increased, the investment is large, and the compensation deg...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/045H02H1/00G01R19/00
CPCG01R19/00H02H1/0007H02H7/045
Inventor 陈胜彭碧君于立涛陈琛董林张陶撖奥洋王黎娄亮赵会亮胡延鹏
Owner STATE GRID SHANDONG ELECTRIC POWER
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