Safety early warning circuit for power distribution operation site

Abstract

The invention discloses a safety early warning circuit for a power distribution operation site. A field intensity over-limit early warning circuit uses a high-voltage trigger circuit to determine whether to reach 80% of an over-limit threshold according to the electric field intensity detected by an electric field sensor; if so, a controllable amplifying circuit carries out amplification, whereinthe amplification factor is controlled by the amplitude of the electric field intensity change calculated by an integrating circuit; a human body induction current calculation circuit works; a division operation circuit carries out a division operation on the electric field intensity and the human body impedance and an induction current acting on a human body is calculated; a safety alarm triggercircuit uses the received induction current as the power supply of the controllable trigger circuit and the change amplitude of the electric field intensity controls an conduction angle of an unijunction transistor T1, so that conduction is triggered when the current is in an over-limit state, a triode Q1 is driven to be in conduction and an electrolytic capacitor E1 is charged through a resistorR24; and acousto-optic safety distance early warning is carried out under the condition that the current exceeds the limit and the allowable duration exceeds an electric shock safety range. Therefore,the accuracy of the safety early warning distance can be effectively improved.

Description

technical field [0001] The invention relates to the technical field of power distribution operations, in particular to a field safety early warning circuit for power distribution operations. Background technique [0002] With the rapid development of distribution network technology, live work has become the development trend of power distribution work, but this kind of operation method also brings certain risks to the personal safety of personnel at the power distribution work site. When the distance between the human body and the charged body is too Small, although it is not in contact with the electrified body, because the insulation strength of the air is less than the electric field strength, the air breakdown may cause electric shock accidents. The existing safety warning of the power distribution work site uses the electric field sensor to detect the power frequency electric field strength of the electrified body in real time , and use the electric field over-limit ear...

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Problems solved by technology

[0004] In view of the above situation, in order to overcome the defects of the prior art, the purpose of the present invention is to provide a safety early warning circuit for power distribution operation site, which effectively solves the problem of using the electric field over-limit early warning method to determine the safe distance between the operator and the high-voltage electrified body. , resulting in inaccurate safety distance warnings

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