High-voltage capacitance bridge spread spectrum device and method

Abstract

The invention relates to a high-voltage capacitance bridge spread spectrum device and method. The high-voltage capacitance bridge spread spectrum device comprises a high-voltage power supply, a standard capacitor, a capacitor to be detected, and a current comparator and is characterized by also comprising a signal extracting circuit, a phase-lock loop circuit and a phase sensitive detection circuit.

Description

technical field [0001] The invention belongs to the field of high-precision instruments and meters, and in particular relates to a high-voltage capacitance bridge frequency spreading device and method. Background technique [0002] The high-voltage capacitor bridge is a special AC bridge for measuring the dielectric loss tgδ value. When measuring, the entire line is formed into a bridge-shaped line, and a comparative measurement method is adopted, that is, an instrument that compares the measured value with a known quantity to determine the size of the measured value. The reason why the high-voltage bridge is called a special AC bridge is that in addition to the difference in structure and measurement requirements, the requirements for the test voltage and frequency are also different during measurement. The test voltage of the general AC bridge measurement The frequency range is from 40Hz to 200kHz, and the voltage is AC voltage within 200V, while the test voltage of the h...

AI Technical Summary

Problems solved by technology

[0004] However, most power equipment will encounter many harmonic components during actual operation, and some specific harmonics will cause damage to them, thus affecting the safety of the entire power grid

and figure 1 The solution in the scheme only works at 50Hz or 60Hz, and it cannot be directly applied at 400Hz, except that the corresponding coefficient needs to be introduced in the calculation of the loss, the main reason is that the measurement of the unbalanced current at 50Hz is lower than And the signal higher than 50Hz is filtered out as much as possible to achieve the best signal-to-noise ratio. If it is used directly at 50Hz-400Hz, the high-frequency signal will be greatly attenuated, which cannot meet the requirements

For example, the direct filtering method of 50Hz bridge can not meet the existing needs, the main reason is that the developed bridge is 50Hz ~ 400Hz broadband bridge, the frequency is not fixed, its index is high, if using multiple sets of filter circuits, its accuracy The number of frequencies is a pair of contradictions. It is difficult to achieve the best filtering effect for all frequencies in the frequency range. Therefore, a high-voltage capacitor bridge based on automatic frequency locking technology has been developed.

Images