Three-phase capacitor voltage division measuring device and method

Abstract

The invention discloses a three-phase capacitor voltage division measuring device and method. The device connected with the high-voltage side of a transformer comprises a first divider arm, a second divider arm, and a measuring main unit. The measuring main unit comprises a first resistor, a second resistor, a position switching amplifier, a filter unit, and a control unit. The control unit comprises a digital-analog converter. A display device comprises a display and keyboard. The three-phase capacitor voltage division measuring device and method has the advantages that the device is specially designed for induced overvoltage withstand test of a distribution transformer outputting with no neutral point, a standard capacitor is used, input impedance is high, and capacitance is stable; the device is capable of measuring three-phase voltage and frequency at the same time, is controlled through a microcomputer, is applicable to online use and is automatically controllable ; the device is simple to use, stable in performance and good in repeatability.

Description

technical field [0001] The invention relates to a measuring device, in particular to a three-phase capacitive voltage dividing measuring device and a measuring method. Background technique [0002] With the rapid development of the electric power industry, the influence of the insulation strength of electrical equipment and the limit level of system overvoltage on the safe and economical operation of the system has become increasingly prominent. The three-phase distribution transformer is the key equipment in the power system. The frequency multiplication induction withstand voltage test of the three-phase distribution transformer can help the relevant staff to find the insulation problem of the equipment in time to avoid serious consequences. [0003] When carrying out the frequency multiplication induction withstand voltage test on a three-phase distribution transformer, usually the theoretical value of the high-voltage side voltage is calculated based on the transformer t...

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Problems solved by technology

[0003] When carrying out the frequency multiplication induction withstand voltage test on a three-phase distribution transformer, usually the theoretical value of the high-voltage side voltage is calculated based on the transformer transformation ratio and the voltage applied to the low-voltage side by the variable frequency power supply, but the actual test voltage There will be deviations from the theoretical value due to the influence of distribution parameters and capacity rise effects. In order to accurately detect the high-voltage electricity, a voltage divider can be used on the high-voltage side of the three-phase transformer to monitor in real time.

However, the current high-voltage dividers are all single-phase, especially when measuring transformers without neutral point output, it is impossible to use the traditional three single-phase dividers to monitor the three-phase voltage at the same time

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