I. Requirements Analysis

 Due to the complex terrain traversed by cable or cable-overhead hybrid lines, coupled with the impact of natural factors such as severe weather and human factors like municipal construction, various faults are highly likely to occur. These faults cause power outages, resulting in significant economic losses. Currently, when faults occur on overhead transmission lines, sectionalization and traveling wave methods are generally employed, which have largely achieved online fault location. However, cable fault location primarily focuses on post-outage fault detection, making it necessary to explore online fault location for cables. Accurate fault location not only reduces the burden of line patrols but also accelerates power restoration, minimizing economic losses from outages. Furthermore, it provides reliable basis for reclosing or manual test energization of hybrid lines.

II. Working Principle

The system comprises three components: high-voltage cable fault and potential hazard monitoring devices distributed at cable joints, a fault data analysis center master station, and user systems. When a fault occurs on a high-voltage cable transmission line, the monitoring device captures the fault traveling wave, processes, stores, and uploads the data. The main station receives data from all devices and performs comprehensive analysis using a topology-based distributed traveling wave algorithm to accurately locate the fault section and fault point. It also identifies the fault type based on the fault waveform. Fault results are pushed to designated mobile devices or accessible via web portals, client applications, and mobile platforms for detailed distance measurement information. This provides maintenance personnel with comprehensive fault data support, significantly reducing fault location time. Concurrently, the monitoring devices capture latent current signals in transmission lines, perform background analysis and computation on these signals, and issue early warnings to prevent potential hazards before they escalate.

III. Features and Functions

1. Fault Location: Fault location serves as the fundamental purpose of high-voltage cables and hidden hazard monitoring devices, enabling the identification of fault sections and fault points while providing extensive waveform data for fault analysis.

2. Fault Type Analysis: After a fault occurs, the fault type is identified by analyzing the current waveforms and power frequency fault current waveforms of phases A, B, and C, providing reference for line maintenance.

3. Early Warning for Potential Faults: By monitoring weak traveling waves in high-voltage cable lines, potential faults are detected early, enabling timely maintenance to prevent tripping failures.

4. Equipment Self-Diagnostics: a) Capable of performing scheduled self-checks on major components, with active alerts triggered for anomalies; b) Equipped with automatic reset and recovery functionality for potential system lockups.

5. Collection of terminal status information: Enable the collection and statistical analysis of terminal status information including solar or CT voltage, battery status, temperature, GPS status, and GPRS signal strength.

6. Advanced Principle: Distributed installation shortens monitoring distances and resolves signal attenuation issues. Dual-end distance measurement enables precise fault location.

7. Powerful Signal Acquisition Unit: The high-voltage cable monitoring device adopts a multi-channel architecture with a single host. It can simultaneously acquire 7 high-frequency signals (3 high-frequency current traveling waves, 3 latent fault current traveling waves, 1 voltage traveling wave) and 8 low-frequency signals (3 power-frequency currents, 4 ground loops, 1 voltage). This robust signal acquisition unit ensures reliable fault recording.

8. Dynamic Wave Velocity Adaptation: The system automatically adjusts the traveling wave velocity based on fault data for enhanced positioning accuracy.

9. High-Precision Synchronized Sampling: Utilizing a GPS timing system and advanced sampling synchronization algorithms, this technology significantly reduces sampling synchronization errors, thereby enhancing ranging accuracy.

IV. Technical Specifications