A single-pole grounding system and its fault detection device and method

Abstract

The present application discloses a single-pole grounding system and a fault detection device and method thereof. Before the normal grounding point is grounded, the positive / negative pole-to-ground impedance of the single-pole grounding system is calculated by acquiring the DC bus voltage and impedance sampling signals of the system. , and then judge whether there is a fault grounding point, which realizes the pre-detection before the system runs, and ensures that the system has no faults before running. The multi-point grounding faults and non-grounding pole grounding faults that occur in the system can be detected by calculating the positive / negative pole-to-ground impedance of the single-pole grounding system again when the system is shut down and the normal grounding point is not grounded. Therefore, the embodiments of the present application realize the detection of multi-point grounding faults in a single-pole grounding system and non-grounding pole grounding faults that may occur simultaneously.

Description

technical field [0001] The present application relates to the technical field of electrical detection, in particular to a single-pole grounding system and a fault detection device and method thereof. Background technique [0002] In photovoltaic power generation systems, photovoltaic cells are prone to polarization, which affects the performance of the photovoltaic cells. In the prior art, the negative electrode (or positive electrode) of the photovoltaic cell array is grounded to form a single-pole grounding system to solve the polarization phenomenon of the photovoltaic cell. [0003] In order to ensure system safety, the above-mentioned single-pole grounding system should be a single-pole single-point grounding system. Such as figure 1 As shown, taking the negative grounding as an example, the normal grounding point is point A, and there is a leakage current detection device connected in series with the ground potential, such as a circuit breaker connected in series wit...

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Problems solved by technology

[0004] However, when the single-pole grounding system has a multi-point grounding fault of the grounding pole (that is, the grounding pole has a faulty grounding point B or more grounding points in addition to the normal grounding point A), or the insulation fault of the non-grounding pole (that is, the grounding point At the same time that there is a faulty grounding point B in the non-grounded pole, there is also a grounding point C in the non-grounded pole, the leakage current may not flow through the grounding branch where point A is located, but will form a leakage current loop through the branch where point B is located, that is, increase The leakage current cannot be detected by the above leakage current detection device, thus causing certain safety hazards, such as maintaining a large leakage current for a long time, which may cause aging of the cable insulation, or even cause a fire, etc.

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