State Grid 1000kV UHV Wuhu Substation Low-Reactance Tilt and Displacement Monitoring Project

Project Background

Ultra-high-voltage substations serve as the core hubs of the power grid, and the safety of their equipment directly impacts regional power supply reliability. The shunt reactor—commonly referred to as a “low‑reactance device”—is a critical component in UHV substations, used to regulate voltage and compensate reactive power; thus, the structural stability of its support columns is of paramount importance. During the peak‑demand winter period and the crucial Spring Festival power‑supply assurance phase at the beginning of the year, operations and maintenance personnel, through meticulous comparison and analysis, promptly identified an inclination risk in the A‑phase support column of the No. 2 main transformer’s 1131 low‑reactance device at the Wuhu Substation. Upon inspection, no abnormalities were found in the foundation, but the support column itself exhibited noticeable tilting and deformation. To prevent further deformation that could lead to equipment collapse, the operating unit implemented temporary reinforcement of the support column. At the same time, there was an urgent need for a high‑precision, non‑contact, real‑time continuous monitoring system capable of tracking the post‑reinforcement deformation and displacement of the support column, evaluating the effectiveness of the reinforcement, and providing early warnings of potential risks.

Monitoring equipment

In view of the characteristic that the low-antenna tilt direction is known (tilt has already occurred), Guilin Spepc Technology adopts Visual Intelligence Deformation Monitor (SP-VDM Series) Single-Device Deployment Plan:

• Monitoring Principle The device is based on machine vision and sub-pixel positioning algorithms. By capturing images of an infrared target mounted above a low‑resistance support column, it calculates in real time the horizontal and vertical displacements of the target relative to a reference target, thereby indirectly reflecting changes in the column’s tilt. The device’s field of view is perpendicular to the direction of the tilting displacement, enabling maximum measurement of the support column’s deformation.

• Core Advantages ：

  • Non-contact measurement : No contact with energized equipment is required, ensuring personnel safety and without disrupting substation operations.

  • Sub-millimeter precision : ±0.5 mm at 25 m, capable of detecting minute deformations.

  • Single-unit multi-targeting : A single device simultaneously tracks targets on multiple support columns, providing synchronized monitoring of all critical support pillars.

  • Built-in constant-temperature control system Temperature control accuracy of ±0.2°C eliminates measurement drift caused by ambient temperature variations, ensuring long-term steady-state accuracy.

  • Visual Review The platform not only transmits displacement data but also streams live on-site imagery, enabling experts to remotely monitor the target and equipment status.

• Deployment method : The visual monitoring device and the reference target are installed at relatively stable locations near the low-voltage line (such as ground observation piers). The monitoring target is mounted using a clamp-type bracket at the top of each pole to be measured, facing the equipment. The device is powered by mains electricity and transmits data and images to the SPEPC monitoring and early-warning platform via 4G or fiber optic links.

Implementation Effectiveness

After the equipment has been operating stably, the monitoring data curves remain smooth, with no false alarms, accurately reflecting the real-time deformation of the low‑resistance support columns following reinforcement. Operations and maintenance personnel, along with grid experts, can remotely access the displacement–time curves for each column and view on-site snapshot images via the platform, confirming that the reinforcement measures are effective and that deformation trends are under control. Leveraging the advantages of non‑contact, high‑precision, multi‑point synchronous monitoring, this solution replaces traditional manual periodic measurements, providing reliable technical assurance for the safe operation of UHV equipment. According to analyses by grid experts, the monitoring data faithfully captures the real‑time deformation of the low‑resistance support columns, offering a scientific basis for subsequent maintenance decisions. This project represents a successful application of visual‑intelligence‑based deformation monitoring technology in the field of structural health monitoring within the power industry.