Method and device for automatically isolating and positioning earth faults of Dc system

Abstract

The invention relates to a device for automatically isolating and positioning earth faults of a Dc system, which overcomes the defects that the conventional device can only monitor specific earth-return circuits or branch circuits of a DC return circuit earth, but cannot isolate fault return circuits from the DC system so as to influence safe operation of normal return circuits because of fault operation of the fault return circuits. The device supplies power to power consumption units by using mutually independent dual DC power supplies and switches fault branch circuit power units from a common power supply to an isolated power supply. All the branch circuits are provided with on-line insulation monitoring device; a communication module is connected with the insulation monitoring device; output signals are connected with an upper PC machine; and the upper PC machine controls all the branch circuits to be isolated sequentially so as to find fault points, receives, stores and comprehensively analyzes monitoring data of all the branch circuits, reports the earth faults of the DC system and displays earth return circuit numbers and earth points in the branch circuits.

Description

technical field [0001] The invention relates to a method and a device for automatically isolating and locating a grounding fault of a DC system of a substation, and belongs to the technical field of operation and maintenance of power station equipment in a power system. Background technique [0002] The DC system in the substation provides DC power for control, signal, relay protection, automatic devices and emergency lighting, etc. It also provides reliable operating power for operations. The reliability of the DC system plays a vital role in the safe operation of the substation. The important role is to guarantee the safe operation of the substation. Due to the wide distribution of the DC system in the substation, many exposed parts, many cables, and long lengths, it is easily corroded by dust and moisture, which reduces the insulation of some weakly insulated components, and even causes DC grounding due to insulation damage. Analysis of DC grounding The reasons generally...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to propose a method and device for automatically isolating and locating ground faults in substation DC systems in view of the defects of existing methods and devices for dealing with ground faults in DC systems that cannot be isolated or located. , isolate the fault branch from the DC system, ensure the normal operation of the non-fault circuit without interference, monitor each branch in real time online, and realize the location of multiple fault points. The device is composed of an isolated power supply, an insulation monitoring device, Composed of switching control device, communication module and upper PC; each DC power unit branch is equipped with a DC insulation monitoring device, the communication module is connected to the branch insulation monitoring device, and its output signal line is connected to the upper PC through the bus system , the switching control device and the output control line are connected to the drive output unit, and then connected to the relay switching element through the transistor switching element

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