A Dielectric Virtual Device for Standard Calibration of Dielectric Loss Factor of High Voltage Capacitor

Abstract

The invention discloses a medium virtual device for standard calibration of a dielectric loss factor of a high-voltage capacitor. The device comprises a current sampling circuit, a phase shift circuit, a constant current output circuit, a micro-processing unit controller and an amplitude modulation circuit, wherein the amplitude modulation circuit responds to change of output currents of capacitors of different standards; the input of the amplitude modulation circuit is connected with the output of the phase shift circuit, and the output of the amplitude modulation circuit is connected with the constant current output circuit; the micro-processing unit controller controls and is connected with the amplitude modulation circuit. According to the device, simulation of the dielectric loss of the capacitor under high voltage can be realized, a simulative resistor does not generate loss of electric energy, non-contact switching can be realized under the condition of electrification, the dielectric correction range is expanded, the working is safe, and the operation is easy; apart from the simulative resistor, change adjustment of the capacitance is also realized, and one standard capacitor is expanded into a plurality of standard capacitors.

Description

technical field [0001] The invention belongs to the field of instruments and meters, and in particular relates to a medium virtual device used for standard calibration of high-voltage capacitor dielectric loss factor. Background technique [0002] When the capacitor is applied with AC voltage, the active loss is called dielectric loss. After the ideal capacitor is applied with AC voltage, the current flowing through the capacitor and the voltage are at an angle of 90 degrees. When the capacitor is lossy, the current flowing through the capacitor is equal to the voltage The included angle of the voltage will be less than 90 degrees. At this time, the included angle δ between the ideal capacitive current Ic is called the loss angle, and its tangent value is the dielectric loss factor (tgδ). [0003] The current standard loss devices all use the structure of the series model, such as figure 1 Shown, is to use a standard capacitor C (close to the ideal capacitor) in series with...

AI Technical Summary

Problems solved by technology

[0013] 2. The withstand voltage of the measuring terminal of the standard capacitor is limited

[0016] As in the above example, if the resistance value of the series resistor reaches more than 3MΩ, then the distributed capacitance between the lead wires connected to the measuring terminal of the standard capacitor will be in parallel with the series resistor, and the moisture and dirt on the surface of the resistor will affect the resistor. the impedance of the

In reality, it is shown that the dielectric loss value will change under different environmental conditions, which cannot meet the requirements of the most standard device.

[0017] 4. Can't switch gears with electricity

[0018] The traditional way of switching gears is realized by mechanical switch K or socket: if the gear is not allowed to be changed under the charged condition, it will bring unsafe factors. On the one hand, an instantaneous open circuit may occur during the switching process, causing the capacitor measurement terminal The potential is too high, resulting in dangerous consequences such as discharge

In addition, the distance between the simulated loss device and the standard capacitor is usually relatively close, and the operator cannot approach it.

Therefore, the current traditional standard loss device needs to shift gears during use, and the test voltage must be reduced to zero, and the capacitor can be discharged before shifting gears

Images