Low-voltage distribution network null wire break protector

Abstract

The invention discloses a low-voltage distribution network null wire break protector. The low-voltage distribution network null wire break protector is characterized by being composed of a switch, a voltage relay, an alternating-current contactor and a signal transmitter. Inlet wires L1, L2 and L3 of the voltage relay are connected with an A phase live wire, a B phase live wire and a C phase live wire of a low-voltage distribution network through the switch respectively, an inlet wire N is connected with a null wire, and normally open contacts 98 and 97 are connected with the B phase live wire and a coil of the alternating-current contactor respectively; the normally open main contact side of the alternating-current contactor is connected with the null wire of the distribution network, and the other side of the alternating-current contactor is connected with a grounding body; one end of the signal transmitter is connected with the normally open contact 97 of the voltage relay, and the other end of the signal transmitter is connected with the grounding body. The low-voltage distribution network null wire break protector has the advantages that when the null wire breaks, work grounding is temporarily formed behind the wire break point so that the three-phase voltage can achieve basic balance; a voltage value is within a rated range of electric equipment, the accident of burning the electric equipment is eradicated, normal work of the electric equipment is not affected, and normal operation of the whole zone area distribution network is not affected either.

Description

technical field [0001] The invention relates to a protection device, in particular to a low-voltage distribution network zero line disconnection protection device, which belongs to the field of electrical technology. Background technique [0002] In the low-voltage three-phase four-wire system sharing the neutral line, if the neutral line (neutral line) is disconnected due to an accident, when the three-phase load is unbalanced, the voltage of each phase will be distorted, and the voltage of each phase load will be abnormal. That is, through the disconnected neutral line, each two-phase load is connected in series to form a loop to withstand the line voltage. In fact, the load is mostly unbalanced, and the three-phase load impedance is different. The current on the two-phase load in the loop is the same, but the load The power is different, so the impedance of the two-phase load is also different, because U=I*Z, so the one-phase load with a smaller load has a large load impe...

AI Technical Summary

Problems solved by technology

[0003] Since the disconnection of the zero line of the low-voltage distribution network will cause a large number of user electrical equipment to be burned, the power supply company needs to pay high maintenance funds

[0004] In addition, when the electrical equipment casing behind the neutral line break point leaks electricity, it is equivalent to the phase voltage. Once the human body touches these electrical equipment casings, it will cause electric shock casualties

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