Single pole grounding system and fault detection device and method thereof

Abstract

The invention discloses a single pole grounding system and a fault detection device and method. According to the single pole grounding system and the fault detection device and method, before the grounding of a normal grounding point, the direct current bus voltages of a system and impedance sampling signals are obtained to calculate the earth impedance of the positive / negative pole of the single pole grounding system, then whether fault grounding points exist is judged, pre-detection before system operation is achieved, and no faults exist before the operation of the system; after the normal grounding points are grounded, whether a grounding fault exists is judged by detecting leaked currents; the grounding pole multipoint grounding fault and non-grounding pole grounding fault which occur during the operation process can be detected when the system is down or the normal grounding points are not grounded through calculating the earth impedance of the positive / negative pole of the single pole grounding system again. Thus, the single pole grounding system and the fault detection device and method achieve the detection on the multipoint grounding fault of the single pole grounding system and the non-grounding pole grounding fault which may occur at the same time.

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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