Testing method of phase shifting angle of zigzag transformer

Abstract

Provided is a testing method of a phase shifting angle of a zigzag transformer. The testing method comprises the steps of enabling a B phase and a C phase of a primary side of the zigzag transformer to be in short circuit; adding alternating voltage between an A phase and the B phase; utilizing voltage meters to respectively measure the voltage UAB between the A phase and the B phase of the primary side, the voltage Uab between an a phase and a b phase of a secondary side and the voltage Ubc between the b phase and a c phase of the secondary side; calculating the phase change ratio Kab=UAB / Uab of AB / ab and the phase change ratio Kbc=UAB / Ubc of AB / bc; and finally solving the phase shifting angle beta of the zigzag transformer by means of the formula cos beta=(2Kbc<2> +Kbc*Kab) / 2Kbc*sqrt(Kbc<2> +kab<2> +Kbc*Kab). According to the testing method, the transformation ratio and the phase shifting angle of the zigzag transformer can be quickly and accurately measured by means of the reading of the two ordinary voltage meters and the formula, the problem troubling people for a long time caused by the testing of the zigzag transformer is solved well, and convenience is created for production, application and maintenance of the zigzag transformer.

Description

technical field [0001] The invention relates to a method for measuring the phase shift angle of a ZN (zigzag) transformer with only two voltmeters, which belongs to the field of measurement technology. Background technique [0002] In addition to several common wiring methods such as Y / Y, Y / Δ, Δ / Δ, etc., transformers also have some special wiring methods, such as figure 1 The zigzag connection method shown (usually expressed in ZN). The transformer with zigzag connection not only has the characteristics of delta connection transformer that can bear single-phase load, but also has the characteristics of star connection transformer with neutral point. Compared with the common Y / Y grounding transformer, the zero-sequence impedance of the zigzag connection transformer is smaller, so it is more suitable for use as a grounding transformer. [0003] Due to the particularity of ZN (zigzag) transformer windings, most transformer manufacturers and designers currently believe that it...

AI Technical Summary

Problems solved by technology

[0003] Due to the particularity of ZN (zigzag) transformer windings, most transformer manufacturers and designers currently believe that it is impossible to measure the number of turns of a single winding or its corresponding transformation ratio and phase angle with ordinary instruments

The existing ZN (zigzag) transformer transformation ratio and phase shift angle measurement device has a very complicated structure, poor power supply stability, and low measurement accuracy

Some manufacturers realize the test of the phase shift angle of ZN (zigzag) transformer by simulating the three-phase power supply site, that is, using single-phase power inverter or column phase to generate three-phase power supply, but this method has great influence on the accuracy and stability of three-phase power supply. The requirements are very high, and many transformer manufacturers and users do not have such conditions

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