"Clearly, normal state for the outlet device structure of converter transformer", said a technician.

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 the converter transformer side casing outlet device in the EHV (extra high voltage) Zhongzhou converter station.

In recent years, State Grid Henan Electric Power Company has independently innovated the ultrasonic phased array imaging measurement device, to help detect the operation state of large transformers accurately and thoroughly for the safe, reliable and stable operation state of 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 measurement imaging system. It 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 is simplified from 11 steps to just 3 steps, the personnel reduced from more than 10 to 2, and the time is shortened from 10 days to 1 hour.

Since 2019, the State Grid Henan Electric Power Research Institute proposed the internal structure detection technology of large transformers by ultrasonic detection and has developed a prototype of the acoustic measurement device. In 2020, the first usage of the device was at the Deyang converter station to inspect the outlet device of the 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 been incorporated into the project of "Health Management Campaign for Substation Main Equipment" of State Grid Corporation of China and is widely practiced in 70 UHV/EHV stations in 10 provincial-level regions, including Henan, Sichuan, Shanxi, Xinjiang Uygur autonomous region, Hunan and Shandong. This effectively improves the safety and reliability of equipment operation and provides strong support for energy and power supply.