One-Click Polarity Test Method of Transformer Group Based on Laplace Transform Overdamping Characteristic

The polarity of three-phase four wire transformer group in power system is directly related to the correct operation of protective devices, merging units, watt hour meters, fault recorders and other equipments, which is one of the key elements for the acceptance point inspection of AC circuits. Nowadays, 2-4 people are required to be allocated at the primary side and the secondary side for polarity test of three-phase four wire transformer group respectively. The single-phase and interphase polarity tests should be carried out phase by phase, which is tedious and inconvenient due to manual pulse transmission through dry battery, manual polarity identification, intercom communication, manual phase switching, manual reading, manual recording, etc. To this end, the automatic polarity test method of transformer group based on Laplace Transform overdamping Characteristic is proposed in this paper, and a complete set of devices is designed and verified. First, the method of polarity identification, automatic phase change and automatic pulse transmission of transformer are proposed based on Laplace Transform overdamping. Second, the one-click polarity test method of transformer group is proposed based on Laplace Transform overdamping. Next, an one-click polarity testing device for transformer group is designed with remote control transmission, automatic storage and printing. Finally, the effectiveness of the method proposed in this paper is verified via a practical case of transformer substation. Results show that the polarity test efficiency of three-phase four wire transformer group can be improved.