State Grid Hubei Electric Power Research Institute's independently developed stray current online monitoring device

(Source: China Electric Power News)

Reprinted from China Electric Power News

“Through the intelligent analysis and tracing platform for stray currents, we can see that the current stray current at Wuhan 220 kV Yebo Mountain Substation is 5 amps, and the equipment within the substation is operating normally.” On March 14, Tang Zeyang, a researcher from State Grid Hubei Electric Power Research Institute and the Hubei Dadi Field Scientific Observation Station for stray currents and energy equipment safety, was monitoring the platform in real-time to check the stray current levels at the substation.

Geomagnetic storms, single-pole operation of DC transmission projects, urban rail transit, and other factors can generate stray currents. “Stray currents entering the ground can corrode track, bridge metal structures, and underground pipelines, reducing the strength of reinforced concrete in nearby buildings, shortening the lifespan of electrical equipment, and posing hidden dangers to the safe and stable operation of urban rail transit,” Tang Zeyang explained. He added that stray currents can also cause increased vibration and noise in transformers within substations, and in severe cases, damage the transformers, affecting the safety and stability of the power grid.

Currently, due to the complex coupling relationships of stray currents, their random spatiotemporal distribution, multiple intrusion paths, difficulty in source tracing, and numerous factors involved in management, the problem of ground stray currents has become a highly valued international and cross-industry common challenge and major technical difficulty.

To address this, the Hubei Electric Power Research Institute of State Grid has independently developed an online stray current monitoring device, relying on the Hubei Dadi Field Scientific Observation Station for stray currents and energy equipment safety. This device is designed to detect the direct magnetic bias current at the neutral point of transformers during operation on-site. It is installed around the transformer and can accurately measure the magnitude and direction of stray currents, as well as the vibration frequency and noise level of the transformer.

The device synchronizes monitoring data to the intelligent analysis and tracing platform for stray currents, automatically conducting trend analysis and anomaly detection, providing scientific and reliable data support for precise management and timely response to stray currents. Currently, the Hubei Electric Power Research Institute has installed 54 monitoring units across 48 substations in Hubei.

In addition, the institute has led the development of the IEEE international standard “Guidelines for Distributed and Synchronous Monitoring of Stray Currents in Urban Rail Transit DC Traction Systems.” “This standard specifies methods for monitoring stray currents and their distribution in urban rail transit DC traction systems, principles for site deployment, technical requirements for monitoring devices and systems, and data processing procedures. It can effectively guide the synchronized monitoring and correlation analysis on the power grid side and the track side, providing data support for stray current management in rail transit,” Tang Zeyang explained.

Next, the Hubei Electric Power Research Institute will continue to improve the deployment and functions of the online stray current monitoring devices, deepen data analysis and research, and provide service support for stray current management across multiple fields such as energy, transportation, and underground pipelines. (Wu Chunxin, Liu Chao, Gan Yiyi)

Editor: Shen Xinrui