Innovative device boosts online detection of cable defects in Jiaxing

State Grid Jiaxing Power Supply Company deployed its self-developed innovative device for online detection and localization of defects in distribution network cables to inspect a 10-kilovolt power line in Jiaxing, Zhejiang province, on Aug 14.

As a key component of urban distribution networks, 10-kV cables are critical for power delivery. Defects in cable joints, accessories or insulation layers can cause partial discharges, which can lead to cable failures, resulting in significant economic losses and social disruption.

The detection of traditional cable defects is carried out after power cut-offs using the oscillating-wave partial discharge method. While effective, the method requires power outages and is time-consuming, reducing inspection efficiency.

To boost the quality and efficiency of inspections and tackle hidden risks early, the company developed an innovative device for the online detection and localization of cable defects. It overcomes certain drawbacks of conventional technology, including low positioning accuracy for multi-branch cables, limited detection coverage, poor real-time performance and weak resistance to interference.

Adopting a dual-end online partial discharge detection mode, the device creates a high-frequency signal propagation model for multi-branch cables. Combined with pulse synchronization technology and adaptive signal-processing algorithms, it captures partial discharge signals amid complex electromagnetic environments and automatically locates discharge points.

The system provides end-to-end online detection to identify potential insulation problems and greatly improves cable-fault response and handling capacity.

During the test, workers followed safety procedures and deployed two devices at opposite ends of the target cable. High-frequency current sensors connected to grounding wires gathered partial discharge data.

Synchronized measurements were conducted, and real-time data was sent to computers to evaluate cable insulation and locate hidden issues. Staff analyzed waveform results and carried out targeted fixes accordingly.

The new approach is significantly more efficient than conventional outage-based inspections. An inspection that once took three hours and multiple workers now only needs two operators and takes roughly 30 minutes.

Moving forward, State Grid Jiaxing will expand the device's application, advance digital and intelligent operational management and deliver more reliable power services to customers.