Insulation monitoring device and method for DC system

Abstract

The invention discloses a monitoring device and method, and particularly relates to an insulation monitoring device and method for a DC system. The insulation monitoring device and method for the DC system is especially applied to insulation monitoring and locating when AC jumps into the DC system. The insulation monitoring device comprises a first CPU, a second CPU and a third CPU. The first CPU is connected with the second CPU through a dual-port RAM, the second CPU is connected with the third CPU through an RS 458 port, the first CPU is connected with a first sampling circuit and a DC voltage input circuit, the second CPU is connected with a liquid crystal display circuit and a memorizer, and the third CPU is connected with a second sampling circuit and a branch sensor input circuit. When a fault that the AC jumps into the DC system happens to the DC system, the monitoring device can be used for monitoring the insulation resistance of the DC system, locating a fault branch and calculating AC input impedance of the branch which the AC jumps into; when the fault that the AC jumps into the DC system does not happen, the insulation monitoring device can be used for monitoring the insulation resistance of the DC system and locating an insulation lowering branch, and is favorable for field staff to maintain the DC system for safety running.

Description

technical field [0001] The invention discloses a monitoring device and method, in particular to a DC system insulation monitoring device and method, especially insulation monitoring and positioning when AC intrusion occurs in the DC system. Background technique [0002] The safe and reliable operation of DC power supply is very important for the safe and reliable operation of substations. However, due to the large number of DC power supply devices and long power supply cables, faults such as DC grounding often occur in actual operation. Although the DC system runs floating, the single-point grounding does not affect the normal operation of the system, but the fault must be found and eliminated as soon as possible, otherwise, when the second point grounding occurs, the relay or protection device will malfunction and cause serious consequences. At present, DC system insulation and line selection devices are widely used in substations, which have achieved good results. [000...

AI Technical Summary

Problems solved by technology

At present, the substation site lacks effective monitoring means and fault alarm measures for "AC intrusion into DC fault", and it is even more difficult to distinguish which kind of AC intrusion occurs

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