Signal conditioning circuit used for high-voltage SF6 switching equipment electric life monitoring

Abstract

The invention provides a signal conditioning circuit used for high-voltage SF6 switching equipment electric life monitoring. The circuit includes a signal extraction module, a signal filtering module and a signal amplification module; the signal extraction module is used for obtaining electrical life monitoring signals and transmitting the signals to the signal filtering module, wherein the signals are processed by the signal filtering module, and then, are transmitted to the signal amplification module; the signal filtering module is used for filtering out power frequency noise interferences and other frequency noise interferences in the signals and includes a multiplier and a band-pass filter; the signal amplification module adopts a low-noise voltage feedback amplifier and is used for amplifying the filtered signals so as to realize signal conditioning; and the electrical life monitoring signals are different voltage signals which reflect distributed impedance in opening and closing situations of a main contact in high frequency. When the circuit is designed through the above manner, extracted signals are clearer, and the accuracy of subsequent data processing by utilizing the electric life signals can be guaranteed.

Description

technical field [0001] The design of this product involves on-line monitoring of switchgear in the electrical field of electric power products, especially a signal conditioning circuit for monitoring the electrical life of high-voltage SF6 switchgear. Background technique [0002] The existing method for calculating the electrical life of a circuit breaker is mainly the cumulative breaking current method, which calculates the electrical life based on the mass loss of the contacts, and is based on the cumulative method of the electrical life curve of the high-voltage circuit breaker. However, the degree of electrical wear of contacts under different short-circuit currents is different, and the wear amount is not linearly related to the magnitude of the short-circuit current. It is not enough to judge the amount of contact burnout only by the cumulative breaking current; therefore, the judgment of the amount of burnout of the contacts should take into account the different wea...

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Problems solved by technology

However, considering that there is a lot of interference in the power frequency signal during the test, the transient process will also bring high-frequency noise, so that the amplitude of the noise signal may be equal to or even exceed the effective signal magnitude.

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