Direct current leakage protection method

A technology of DC leakage and leakage current, which is applied in the direction of protection that responds to fault currents, emergency protection circuit devices, emergency protection devices that automatically disconnect, etc., can solve the problems of large volume, easy interference, and high production cost. Achieve the effects of improving timeliness and accuracy, high reliability, and reducing engineering workload

Active Publication Date: 2020-08-04
南京国臣直流配电科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the related active devices are susceptible to interference during the detection process, and the high manu

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Such as figure 1 As shown, a DC leakage protection method, the above-mentioned protection method is applied to an ungrounded system or a high-impedance grounded system, and specifically includes the following steps:

[0031] (1) Determine whether the insulation resistance of the DC bus has decreased or the ground fault has occurred by detecting the insulation resistance of the DC bus to the ground (use the balance bridge resistance measurement method on the positive and negative buses of the DC power supply to detect the resistance of the DC bus to the ground. When the resistance of an electrode to the ground is less than the set value, it is judged that the electrode has a decrease in insulation resistance or a ground fault). The CPU controls the driving circuit, intermittently or periodically disconnects the IGBT to realize the intermittent or periodic change of the resistance between the DC bus (non-faulty pole) and the ground), and changes the distance between the o...

Embodiment 2

[0036] Such as figure 1 As shown, a DC leakage protection method, the above-mentioned protection method is applied to an ungrounded system or a high-impedance grounded system, and specifically includes the following steps:

[0037] (1) By detecting the insulation resistance of the DC bus to the ground, it is judged whether the insulation resistance of the DC bus has decreased or the ground fault has occurred (use the unbalanced bridge resistance measurement method on the positive and negative DC power supply bus to detect the resistance of the DC bus to the ground, when the DC bus When the ground resistance of one electrode or two electrodes is less than the set value, it is judged that the insulation resistance of the electrode or both poles of the DC bus bar has decreased or the ground fault has occurred);

[0038] When it is detected that there is a decrease in insulation resistance or a ground fault in a certain pole of the DC bus (when the CPU detects that the fault signa...

Embodiment 3

[0044] Such as figure 2 As shown, a DC leakage protection method, the above-mentioned protection method is applied in the grounding system, specifically includes the following steps:

[0045] (1) In the grounding system, the current sensor on the grounding line is used to detect the current on the grounding line of the DC power supply, so as to determine whether there is a decrease in insulation resistance or a grounding fault on the DC bus. When the resistance decreases or there is a ground fault, disconnect the grounding wire between the original grounding electrode and the earth (there is a switch on the grounding wire). input impedance device ( Figure 4 device, so that the grounding electrode is in the cycle of grounding and non-grounding, when the positive is grounded, the negative is not grounded, and when the negative is grounded, the positive is not grounded), inducing a pulsating leakage current between the fault point and the ground;

[0046] (2) Use the electrom...

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PUM

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Abstract

The invention discloses a direct current leakage protection method. The protection method can be applied to a grounding system, a non-grounding system, or direct-current bus grounding or a non-grounding random switching system. According to the protection method, passive detection is realized by utilizing an electromagnetic coil principle, an electric leakage fault can be rapidly detected, a faultalarm can be sent out, a fault loop can be automatically cut off, the engineering quantity is reduced, and the timeliness and the accuracy are improved; meanwhile, the method is high in reliability and can be widely popularized and applied.

Description

technical field [0001] The invention relates to a DC leakage protection method and belongs to the technical field of DC system leakage protection. Background technique [0002] Due to its advantages of safety, reliability, economy, high efficiency, and easy access to new energy and energy storage equipment, the application range of DC systems continues to expand. In order to prevent human body contact, grounding, AC intrusion and other faults and abnormal working conditions in the DC system, resulting in personal and equipment safety, the DC system must have the function of leakage protection. The existing DC leakage protection usually adopts active devices, and the purpose of protection is achieved by using active devices to detect DC leakage current signals. However, the related active devices are susceptible to interference during the detection process, and the high manufacturing cost and large size are difficult to promote, which hinders the application and development ...

Claims

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Application Information

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IPC IPC(8): G01R31/52H02H3/00H02H3/14H02H3/16H02H3/04H02H1/00
CPCG01R31/52H02H3/00H02H3/14H02H3/16H02H3/042H02H1/0007Y04S10/52
Inventor 刘向东陈文波李忠张保邹学毅严建海余学文仝浩梅中华朱礼建
Owner 南京国臣直流配电科技有限公司
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