On September 26, two technicians from the state grid Henan Institute of Electricity Technology used a self-developed ultrasonic phased array imaging measurement device to inspect the internal structure of a transformer in the EHV Zhongzhou converter station.

In recent years, state grid Henan Electric power company has been upgrading its ultrasonic phased array imaging measurement device to  accurately and thoroughly detect the operation state of large transformers ensuring the safe, reliable and stable performance of the power grid equipment. The core technologies of the device integrate large depth detection, wide range automatic scanning and three-dimensional ultrasound imaging, which consists of an ultrasonic phased array probe, bionic mechanical accessories and a three-dimensional ultrasound imaging system. The device can realize the accurate imaging of the transformer's internal structure, like insulating partition and insulating grading shield under the charged state. Compared with the oil discharge and internal inspection, the process has been simplified from 11 steps to three steps, the personnel reduced from more than 10 to two, and the time is shortened from 10 days to one hour.

The state grid Henan Electric Power Research Institute had been proposing the project since 2019, and developed a prototype. In 2020, the device was used for the first time at the Deyang converter station to inspect the outlet device of converter transformer. In 2021, the orbital scanning device was developed to realize automatic linear scanning and troubleshoot the installation status of the insulating partition of a 500kV transformer for the first time. In 2023, a bionic-adapted mechanical scanning device was developed to achieve wide range scanning and three-dimensional imaging.

At present, the technology has converged into the project of "Health Management Campaign for Substation Main Equipment" of State Grid Corporation of China and is widely used in 70 UHV/EHV stations in 10 provinces and regions, such as Henan, Sichuan, Shanxi, Xinjiang, Hunan, and Shandong, which has effectively improved the safety and reliability of equipment operation and provided strong support for energy and power supply.