Design of Current Tester with Wireless Synchronization for Power Transformer

Aiming at the characteristic of long cables among the primary-side equipment, secondary-side equipment and intelligent control cabinet of the transformer system, a current tester based on wireless synchronization is developed for electrical detection of transformer systems, the current tester is developed with wireless synchronization for electrical characteristics testing. The current tester consists of a wireless three-phase current source and a wireless measuring machine. The wireless three-phase current source adopts inverter modulation with a current booster to generate three-phase alternating current with a maximum of 300A. The wireless measuring machine uses a dedicated metering chip to sample the secondary-side current signals and analyze electrical characteristics. Meanwhile, a wireless communication module is designed and a synchronization algorithm is proposed to accurately calculate the phase difference of the three-phase currents. Finally, the current tester is applied to a new 220kV substation in Fujian Province to carry out on-site current-through tests. The results show that the three-phase AC signals generated by the current tester have high accuracy, and the transformer ratio and phase of the transformer system can be accurately calculated through wireless synchronization, which meets the requirements of practical engineering applications.