Insulation pre-inspection device for main wiring of low-voltage circuit breaker based on piezoelectric ceramic transformer

Abstract

The invention discloses a low-voltage circuit breaker main wiring insulation pre-checking device based on a piezoelectric ceramic transformer, and belongs to the technical field of low-voltage apparatuses. The device comprises a piezoelectric ceramic transformer high-voltage generating circuit, a piezoelectric ceramic transformer harmonic drive circuit, a piezoelectric ceramic transformer harmonic detection circuit, a short-circuit detection sensing circuit and a main measurement and control circuit. The piezoelectric ceramic transformer high-voltage generating circuit is connected with the piezoelectric ceramic transformer harmonic drive circuit, the piezoelectric ceramic transformer harmonic detection circuit and the short-circuit detection sensing circuit 4, the piezoelectric ceramic transformer harmonic drive circuit is connected with the short-circuit detection sensing circuit and the main measurement and control circuit, the main measurement and control circuit is connected with the piezoelectric ceramic transformer harmonic detection circuit and the short-circuit detection sensing circuit and transmits data to a user through a data output end, and the short-circuit detection sensing circuit is connected with a load side of a low-voltage circuit breaker QF of an access power grid. The device can detect low-resistance short-circuit failures and high-resistance short-circuit failures lower than the normal value but higher than the low resistance value.

Description

technical field [0001] The invention belongs to the technical field of low-voltage electrical appliances, and in particular relates to a low-voltage circuit breaker main wiring insulation pre-inspection device based on a piezoelectric ceramic transformer. Background technique [0002] After the traditional low-voltage circuit breaker is closed and running, it can automatically trip quickly to eliminate the fault when the power supply and distribution line is short-circuited. Before closing, the low-voltage circuit breaker does not have the function of judging the insulation status of the main wiring on the load side. In the actual application process of the power supply and distribution system, accidents often occur due to the closing of the low-voltage circuit breaker when the power supply and distribution line on the load side is in a short-circuit state. The development of economy and society has further improved people's requirements for the reliability of power supply a...

AI Technical Summary

Problems solved by technology

[0003] The technical information on the pre-checking of low-voltage circuit breakers before closing can be found in published Chinese patent documents. Invention patent application number CN87107258.0 provides "carrier frequency pre-check short-circuit protection circuit" and Chinese utility model patent authorization announcement number CN202495703U discloses "circuit breaker for pre-check line fault", etc. The method of qualitatively judging whether there is a short-circuit fault, but does not mention the interference problem of the distributed capacitance between the three-phase wires and between the relative grounds; Device", Chinese Invention Patent Application Publication No. CN102012474A, "Coal Mine High and Low Voltage Power Supply Line Phase-to-Phase Short-circuit Pre-detection Technology", Chinese Invention Patent Application Publication No. CN102377157A, "A Fire-fighting Intelligent Electric Control Device" and Chinese Invention Patent Authorization Announcement No. CN102435879B proposed "a method for detecting the line before closing", etc., after the grid power on the power supply side of the low-voltage circuit breaker is transformed by a transformer or power electronic device, it is applied to the main wiring on the load side of the low-voltage circuit breaker to detect whether There is a short-circuit fault. In the above-mentioned several patent solutions, if the insulation breakdown of the transformer or the breakdown of the power electronic device occurs, the grid power will be directly applied to the load side of the low-voltage circuit breaker that is in the opening state, and there will be an emergency for the staff. Potential safety hazards that cause injury; the third category, such as the "Low-voltage circuit breaker main wiring short-circuit detection sensor device before closing" disclosed in the Chinese invention patent application publication number CN103176099A, uses low-voltage testing to quantitatively measure the main wiring on the load side of the low-voltage circuit breaker The ground-to-ground insulation resistance value and the phase-to-phase insulation resistance value, but what it detects is only the low-resistance short-circuit resistance value between the phase lines and the phase-to-ground existence, but cannot detect the phase-to-phase and phase-to-ground The resistance value of the high resistive short circuit that exists between

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