A detection device for alternating current mixed in a direct current power supply system

Abstract

The invention provides an alternating current infiltrating detector for a direct current supply system. The system comprises a direct current leakage current sensor arranged on a positive bus-bar +KM and a negative bus-bar -KM of the direct current circuit, a balance resistor R1, a balance resistor R2, a balance resistor R3 and a balance resistor R4, wherein the balance resistor R1, the balance resistor R2, the balance resistor R3 and the balance resistor R4 are sequentially connected in the positive bus-bar +KM and the negative bus-bar -KM in series, the resistor R2 and the resistor R3 are connected to the ground through a relay J1 and a diode D1, a capacitor C1 and a resistor R5 are connected between the negative bus-bar -KM and the relay J1 in series, a true RMS measuring circuit is connected between the resistor R3 and the resistor R4, a first measuring port in the true RMS measuring circuit is used for measuring the insulating grounding voltage of the direct current, and a second measuring port is used for measuring the infiltrated voltage of the alternating current. According to the alternating current infiltrating detector for the direct current supply system, the amplitude of altering current signals is reduced through a mechanical relay, half-wave rectification is conducted on the altering current, and the direct leakage current sensor on the system feed-out sub-circuit can detect the signals; furthermore, two kinds of signals are detected through one senor, half sensors are saved, the economical effect is remarkable, and the device construction is simple.

Description

technical field [0001] The invention relates to the technical field of power system maintenance, in particular to a detection device for alternating current mixed in a direct current power supply system. Background technique [0002] When the DC power supply is mixed with the AC power supply, the DC system will be grounded, which may cause the protection to refuse to operate or malfunction, thereby causing serious accidents. The current DC insulation monitoring devices do not have the functions of measuring and alarming for AC channeling and DC faults. It can’t alarm, and can’t accurately measure the mixed AC, or can only measure the value of low voltage, can’t measure the value of high voltage, and can’t use the DC leakage current sensor to locate the branch circuit mixed with AC. If you want to replace the device with this function , needs power outage, which will seriously affect the reliability of power supply and the normal life order of the society and residents; if it...

AI Technical Summary

Problems solved by technology

[0002] When the DC power supply is mixed with the AC power supply, the DC system will be grounded, which will cause the protection to refuse to operate or malfunction, thereby causing serious accidents. The current DC insulation monitoring devices do not have the functions of measuring and alarming for AC channeling and DC faults. It can’t alarm, and can’t accurately measure the mixed AC, or can only measure the value of low voltage, can’t measure the value of high voltage, and can’t use the DC leakage current sensor to locate the branch circuit mixed with AC. If you want to replace the device with this function , needs power outage, which will seriously affect the reliability of power supply and the normal life order of the society and residents; if it is combined with the replacement of DC system or the transformation of the whole station, it will be a very long work

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