Ultrasonic partial discharge sensor designed with high-precision signal frequency reduction circuit

Abstract

The invention discloses an ultrasonic partial discharge sensor designed with a high-precision signal frequency reduction circuit, which includes a high-precision signal frequency reduction circuit. The high-precision signal frequency reduction circuit includes an electrically connected detection circuit and a filter circuit. The detection circuit Including a first resistor R1, a second resistor R2, a third resistor R3, a first diode D1, a second diode D2, a first capacitor C1 and a second capacitor C2; the filter circuit includes a fourth resistor R4, The fifth resistor R5, the sixth resistor R6, the seventh resistor R7, the eighth resistor R8, the ninth resistor R9, the third capacitor C3, the fourth capacitor C4, the fifth capacitor C5 and the operational amplifier A. The ultrasonic partial discharge sensor designed by the high-precision signal frequency reduction circuit provided by the present invention has a high-precision special signal frequency reduction circuit, the circuit structure is simple, and both small signal and large signal processing are taken into account, which can greatly improve the detection accuracy and accuracy of partial discharge. Detection sensitivity.

Description

technical field [0001] The invention relates to the technical field of circuit design of an ultrasonic partial discharge sensor, in particular to an ultrasonic partial discharge sensor designed with a high-precision signal frequency reduction circuit. Background technique [0002] At present, there are a large number of low-voltage switchgears in power plants and substations, the operating environment is harsh, and the internal components are prone to aging, which leads to partial discharge. Partial discharge refers to the discharge that occurs between the electrodes but does not penetrate the two electrodes. It is due to defects in the insulation of the equipment or defects caused in the production process, and repeated breakdown and extinction occur under the action of high electric field strength. [0003] The ability of this kind of discharge is very small, so its short-term existence does not affect the insulation strength of electrical equipment, but if electrical equi...

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Problems solved by technology

However, in the prior art, the detection effect of the detection circuit is poor, and it is prone to inertial distortion, negative peak cutting distortion, and noise will be introduced at the same time; the series diode envelope detection is suitable for large signal peak detection, and cannot detect small signals. It is necessary to add active components such as operational amplifiers, which have high requirements for operational amplifiers and increase the cost of the device; the traditional filter circuit has a small dynamic response range and cannot handle both small and large signals; the traditional passive filter circuit is amplified in the passband The multiple and its cutoff frequency vary with the load, which is not suitable for occasions with high signal processing requirements. At the same time, the passband of traditional filters is also affected by the input resistance and output resistance, that is, the internal resistance of the input signal source will make The resonance point of the filter network is shifted, thereby reducing the filtering effect; the overall signal down-frequency is greatly affected by external interference, which makes the sensitivity of the detection device low

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