Instantaneous grounding fault finder designed based on STM32F103T6

Abstract

The invention discloses an instantaneous grounding fault finder designed based on STM32F103T6. The instantaneous grounding fault finder comprises an equipment power supply, a touch screen, an STM32F103T6 main control module, a program downloading module, a data communication module, a USB interface module, a V+ and V- voltage sampling module and an eight-channel CT current sampling module, whereinthe equipment power supply is electrically connected with the program downloading module, the STM32F103T6 main control module, the USB interface module, the V+ and V- voltage sampling module and theeight-channel CT current sampling module. According to the instantaneous grounding fault finder designed based on STM32F103T6, the voltage and current magnitude of a direct-current system are sampledat a high speed, an insulation fault of the direct-current system is judged according to the voltage variation, and a grounding branch is judged according to the current variation trend; and meanwhile, the insulation fault and the distributed capacitance influence branch are distinguished by adopting the current and voltage variation trend difference, so that the problem of troubleshooting of instantaneous grounding faults of the direct-current power supply is solved, and the safety and reliability of power operation are ensured.

Description

technical field [0001] The invention belongs to the technical field of electric fault finding, and in particular relates to an instantaneous ground fault finding instrument designed based on STM32F103T6. Background technique [0002] As the power supply of secondary equipment for power generation and transformation, the safety and reliability of the DC system is very important; the DC system is an ungrounded system. In order to ensure that the system is not grounded, the design allows the DC system to be grounded at one point. Grounding point", the grounding point is the internal balance bridge of the DC system insulation monitoring device host. [0003] Instantaneous grounding of DC power supply system is a kind of grounding fault of DC power supply system. The harm is the same as that of DC grounding fault. There are two main reasons for instantaneous grounding fault: 1. Mechanical vibration causes damage to the insulation layer, such as the power cord in the motor is worn...

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Problems solved by technology

[0004] However, the instantaneous ground fault of the DC power system is seriously harmful, resulting in abnormal ground voltage of the DC power system busbar, and the fault insulation monitoring device with sufficient time will flash an alarm signal, and the serious situation will directly lead to protection malfunction or refusal to operate;

[0005] Although the "DL / T 1392-2014 Technical Conditions for Insulation Monitoring Devices for DC Power System" promulgated by the National Energy Administration in 2015 clearly requires that the insulation fault detection time of the insulation monitoring device should not exceed 180s, but the time caused by the protection relay is at the ms level. Due to the instantaneous ground fault The characteristics are: short grounding time and frequent grounding faults; so the efficiency of the insulation monitoring device is still very low, which is far from meeting the needs of field operation. In the early years, people did not analyze the DC grounding enough, and the efficiency of the fault monitoring equipment and the action efficiency of the protection equipment are quite different. , Electric power maintenance personnel cannot find some instantaneous grounding faults, and lack of analysis data for protection misoperations caused by instantaneous grounding, resulting in the lack of on-site data for analysis of some electric accidents. Natural disappearance or accident magnification

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