By EECTECH | 27 July 2020 | 0 Comments
The principle of voltage division of capacitive voltage transformer
The capacitive voltage divider is composed of a porcelain sleeve and several series capacitors installed in it. The porcelain sleeve is filled with insulating oil that maintains a positive pressure of 0.1MPa, and a steel bellows is used to balance different environments to maintain the oil pressure. The capacitive voltage divider can be used as a coupling capacitor Connect the carrier device.
The capacitive voltage transformer is mainly composed of a capacitive voltage divider and a medium voltage transformer. The medium voltage transformer consists of a transformer, a compensation reactor and a damping device installed in a sealed oil tank, and the space on the top of the oil tank is filled with nitrogen. The primary winding is divided into a main winding and a fine-tuning winding, and a low-loss reactor is connected in series between the primary side and the primary winding. Because the non-linear impedance and inherent capacitance of capacitive voltage transformers sometimes cause ferromagnetic resonance in the capacitive voltage transformer, a damping device is used to suppress resonance. The damping device is composed of a resistor and a reactor and is connected across the secondary winding. Above, the damping device has a very high impedance under normal conditions. When the ferromagnetic resonance causes overvoltage, the reactor has saturated and only the resistive load is left before the medium voltage transformer is affected, so that the oscillation energy is quickly reduced. Capacitor voltage transformer is a voltage transformer that is used to extract voltage from series capacitors and then transformed into a voltage source for meters and relay protection. Capacitor voltage transformers can also couple the carrier frequency to transmission lines for long distances. Communication, remote measurement, selective line high-frequency protection, remote control, teletype typing, etc. Therefore, compared with the conventional electromagnetic voltage transformer, the capacitive voltage transformer can prevent the ferromagnetic resonance caused by the saturation of the iron core of the voltage transformer, and has many advantages in economy and safety.
The performance of EECTECH's capacitive voltage divider transformer has reached the industry's top level, with an accuracy of 0.5%, high temperature resistance (-40℃~+150℃), high voltage resistance (42KV in air), zero partial discharge, and greatly increased the service life of the transformer And grid security
BY : www.eectech.cn
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