Measure for solving AC, DC earthing and short circuit and novel design of DC system

Abstract

Aiming to solve the problems that the electric power plant trips due to the ground fault for the strings under alternating current or direct current condition, and a plurality of accidents appear, for example, the device is damaged, the important relay coil with easy incorrect-tripping is connected with a shunt resistor in parallel, the communication is carried out between the electric devices, and a rectification, insulating and tripping functional switch is installed on a direct-current power supply branch circuit, so that the influence on the fault source is reduced or isolated. The invention provides a novel direct current system design principle and a method, a special hall sensor for the unbalanced current is adopted, a grounding resistance-capacitance loop is increased, the unbalanced current of the grounding branch circuit is increased, the sensitivity of measurement is improved, a distributed on-site monitoring module finishes the data acquisition and the data transmission of the busbar voltage, the unbalanced current, the on / off state, and the like, the monitoring center finishes processing all the data and warning according to the logic of the design, the tripping command is transmitted to the fault branch circuit through the distributed on-site monitoring module, and a switch with tripping function is used for shutting the fault branch circuit off in time after receiving the command. Therefore, the technical problem that the fault range is extended due to the short circuit and the ground fault for strings under the alternating current and the direct current condition is solved.

Description

(1) Technical field: [0001] The present invention aims at solving the technical problems of DC system power supply faults such as series AC, DC grounding and DC short circuit, or causing the expansion of other power supply DC main equipment accidents, and proposes new solutions and methods, and uses the new solutions and methods to propose DC The new technology, ideas, principles and methods of system design update the DC system design concept, solve the technical problems existing in the current DC system, and are applicable to any field of DC systems and DC operating power systems. (two) background technology: [0002] At present, in large-scale enterprises or power systems, the operating power supply of the DC system is a conventional design: including battery packs, rectifier charging devices, power distribution circuits, monitoring and insulation monitoring devices, etc., the DC bus is directly connected to the The operating power supply of the main equipment, the exist...

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Problems solved by technology

[0002] At present, in large-scale enterprises or power systems, the operating power supply of the DC system is a conventional design: including battery packs, rectifier charging devices, power distribution circuits, monitoring and insulation monitoring devices, etc., the DC bus is directly connected to the The operating power supply of the main equipment, the existing problem is: the failure of the DC power supply system (such as series AC, DC grounding, DC short circuit, etc.) can directly affect the safe operation of other DC operating power supplies and the main equipment through the DC bus, causing other operating power circuits to fail. The malfunction or refusal of the main equipment of the main equipment will expand the accident. At present, the insulation monitoring and line selection device commonly used in the DC system is the AC injection method, which cannot correctly judge the grounding fault of the rectifier circuit of the improved DC system. The monitoring and line selection device has relatively high requirements for DC sampling accuracy, which is not easy to implement and the inspection cycle is long

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