Direct-detection type intelligent direct-current system insulation and state diagnosis instrument

Abstract

The invention relates to a direct-detection type intelligent direct-current system insulation and state diagnosis instrument comprising a diagnosis host machine which mainly comprises a signal generator, a power amplifier, a signal injector, a signal receiver, a signal amplifier, an A/D (Analog to Digital) conversion module, a singlechip system and an alarm, and a handheld split core type currenttransformer. The total insulation state of a major loop is detected by using an alternating-current injection detection mode, whereas which branch generates insulation reduction on earth is detected by using the direct-current transformer. When multiple branches are grounded at the same time, the grounded branches can be detected at the same time, and the diagnosis precision is high. Meanwhile, the detection method is implemented by using a singlechip. Compared with a balanced bridge method and an alternating current injection method in the prior art, the invention adopts a microcomputer technology and has the characteristics of high integrated level, high judgment speed, high detection sensitivity, convenience in operation, strong anti-jamming capability, accuracy in fault location and the like.

Description

technical field [0001] The invention relates to the field of power system automation, in particular to a direct-measurement intelligent DC system insulation and state diagnostic instrument. Background technique [0002] The relay protection and control in the substation adopt 110V (or 220V) DC power supply, that is, the DC power supply system of the substation controls the operation of the secondary system of the entire substation. Therefore, the safety of the DC power supply system of the substation directly affects the operation status of the substation. . [0003] The DC system of the substation uses batteries to store energy, uses chargers to supplement energy, and continuously transmits electric energy to the protection, monitoring, and communication systems of the whole station to ensure its safe, stable, and reliable operation. The DC system is an insulation system. Normally, the insulation resistance of the positive and negative poles to the ground is equal, and the...

AI Technical Summary

Problems solved by technology

Although the balance principle of the DC balance bridge method is widely used, it has the following disadvantages: it cannot detect the situation when the insulation of the positive and negative poles of the DC system drops equally; even if the alarm is issued, the insulation resistance of the system to the ground cannot be directly obtained; To determine which branch is grounded, only by pulling the switch can it be judged which branch is grounded. If the insulation resistance of more than two branches drops, the judgment will be more time-consuming and laborious; the sensitivity is very low, and the detection system itself There is a resistance to ground of about 60k

It is divided into single low frequency detection and variable frequency detection (dual frequency detection). The insulation detection system realized by this principle has the following insurmountable shortcomings: When multiple branches are grounded at the same time, multiple branches cannot be detected at the same time

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