DC system ground fault detection system

Abstract

The invention provides a direct current system ground fault detection system. The direct current system ground fault detection system comprises multiple voltage sensors, multiple data processing module, a concentrator, an upper host and an alarm, wherein the multiple voltage sensors are arranged at the tail ends of a bus and branches in a direct current system respectively; the multiple data processing modules are arranged corresponding to the bus and the branches; the input ends of the data processing modules are connected with the output ends of the voltage sensors; the output ends of the data processing modules are connected with the concentrator; the concentrator is connected with the upper host in a wired or wireless mode; the upper host is connected with the alarm. The direct current system ground fault detection system can accurately and timely detect whether the bus or the branches in the direct current system have ground faults or not and can effectively avoid influence of the direct current system and human factors on a detection result.

Description

technical field [0001] The invention relates to a detection system, in particular to a ground fault detection system of a DC system. Background technique [0002] The DC system is an indispensable equipment in the power system. It is widely used in power plants such as hydropower and thermal power. The DC system provides power for other DC equipment in the electric field. For example: the DC system is used for signal equipment, protection, automatic devices, and emergency lighting. , emergency power supply and circuit breaker opening and closing operations to provide DC power; therefore, the stability of the DC system is directly related to the stability of the power supply, and the ground fault of the DC system affects the stable operation of the DC system is the most important It is also one of the most common faults; at present, the detection of ground faults is mainly divided into manual monitoring. Manual monitoring uses instruments to directly measure the end of the DC...

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Problems solved by technology

[0002] The DC system is an indispensable equipment in the power system. It is widely used in power plants such as hydropower and thermal power. The DC system provides power for other DC equipment in the electric field. For example: the DC system is used for signal equipment, protection, automatic devices, and emergency lighting. , emergency power supply and circuit breaker opening and closing operations to provide DC power; therefore, the stability of the DC system is directly related to the stability of the power supply, and the ground fault of the DC system affects the stable operation of the DC system is the most important It is also one of the most common faults; at present, the detection of ground faults is mainly divided into manual monitoring. Manual monitoring uses instruments to directly measure the end of the DC system (that is, the bus bar of the DC system or the grounding end of each branch) through manual inspection. The grounding status of this method is huge and wastes manpower. More importantly, the monitoring results are inaccurate and prone to missed detection, which seriously affects the stability of the DC system. With the development of society, a balanced bridge has appeared. In this method, it is necessary to disconnect the power supply of each branch one by one to determine the faulty branch, and it is easy to cause faults and misoperations during the opening and closing process, which also seriously affects the stability of the DC system; therefore, signal injection gradually appears Inject low-frequency signals or double low-frequency signals into the DC system. Although these methods effectively prevent the malfunction of opening and closing, the injected low-frequency signals are easily affected by the capacitance to ground in the DC system, so they cannot be accurately detected. Earth fault in DC system

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