A ground fault monitor is an electrical device used to detect and monitor ground faults in power systems. It can effectively ensure the safe and stable operation of power systems and avoid accidents such as equipment damage and casualties caused by ground faults1 . The following is a detailed introduction:
Working principle 2 : The ground fault monitor is connected between the active conductor and the earth and superimposed with the measuring voltage Um . In the event of a ground fault, the ground fault RF closes the loop between the system and the earth, triggering a measuring current proportional to the ground fault Im . The measuring current generates a voltage drop across the measuring resistor RM , which is evaluated by the electronics and an output signal is generated if it exceeds a certain value which is equivalent to the specified insulation resistance.
Functional feature 1 : The main function is to accurately monitor the grounding fault in the power system. Once the system has a grounding fault, or the cable is damaged and causes leakage, the device will quickly trip and cut off the power supply and trigger an alarm. At the same time, some grounding fault monitors can also accurately monitor and promptly alarm the open circuit, short circuit and abnormal grounding resistance of the power system grounding wire.
Application scenarios : Suitable for places such as mines and factories with a large number of mobile equipment or complex power lines, to ensure the safe operation of mobile cables1 . It is also commonly used in DC or AC two-wire and three-phase ungrounded feeding systems, and can effectively deal with ground faults caused by reasons such as aging of busbar insulation to the ground5 . In addition, in some places with high electrical safety requirements, such as hospitals and data centers, ground fault monitors can ensure the reliability of the power supply system and the safety of personnel and equipment.
Typical product 1 : For example, Zhuzhou Fude's FD-GFGC-Z100 is a microprocessor-based combined ground wire monitoring and ground fault relay resistance grounding or solid grounding system, which can be applied to scenarios such as mobile cables in mining power systems. Ifm's ground fault / insulation monitor can be easily installed in an existing AS-i system, and can measure the bias voltage between the conductor and the ground, and detect symmetrical or asymmetrical grounding or insulation faults6 .