Table of Contents

Product Overview

During long-term operation of high-voltage power cables, the grounding status of the metal sheath directly determines cable service life and power supply reliability of the grid. Under normal operating conditions, current flowing through the cable core induces potential on the metal sheath. Once faults occur including multi-point grounding, stolen grounding wires or failed cross-bonding systems, sheath circulating current will surge abnormally. Mild consequences involve local cable overheating and accelerated insulation aging; severe cases trigger short-circuit faults and large-scale power outages.

Developed to solve this industry pain point, the cable sheath grounding current online monitoring system thoroughly replaces inefficient periodic manual inspection. It continuously tracks the amplitude and waveform changes of grounding current round-the-clock to realize early detection, pre-warning and troubleshooting of hidden hazards. Extended functions such as cable anti-theft and system self-diagnosis are also integrated. It builds an all-time safety protection network for high-voltage cable lines of 35kV and above, serving as an indispensable core monitoring device for condition-based maintenance of smart grid cables.

Product Description

The whole system consists of four modules: split-core sheath circulating current sensors, on-site acquisition terminals, remote data transmission units and background monitoring platform. It applies to grounding current monitoring of transmission & distribution power cables rated 6.6kV and above.

Adopting non-intrusive installation, the system never modifies the original cable grounding scheme or primary wiring layout. Signals are collected via magnetic field coupling without direct electrical connection to the primary power system, bringing zero interference to grid operation.

Equipped with high-precision current sensing technology, the system captures tiny fluctuations of grounding current in real time. Built-in intelligent algorithms automatically distinguish normal load fluctuations from abrupt abnormal circulating current. Alerts will be instantly pushed to maintenance staff once current exceeds preset thresholds, rises/drops sharply or falls to zero, with accurate fault location available.

In addition, the system supports cable anti-theft identification. It triggers immediate alarms once grounding wires, cross-bonding cables or grounding boxes are cut or stolen, effectively lowering theft risks of cable auxiliary facilities.

Comprehensive self-diagnosis functions are embedded: the terminal continuously monitors its own power supply, communication links and hardware operating status. It uploads fault information to the cloud platform proactively upon malfunctions to avoid monitoring blind areas.
Maintenance personnel can check real-time current curves and historical data via PC or mobile terminals. The system automatically generates daily, weekly, monthly, quarterly and annual statistical reports, providing complete data support for cable condition evaluation and maintenance planning. It greatly reduces on-site inspection workload and improves digital operation & maintenance levels of power cables.

Core Technical Specifications

Parameter Item	Technical Index
Applicable Voltage Level	35kV, 110kV, 220kV and above high-voltage cable lines
Measuring Range	0~300A (50Hz), covering all working conditions of conventional HV cable sheath current
Measuring Sensitivity	≤±0.1A, precisely captures tiny abnormal variations of grounding current
Measurement Accuracy	Reading ×1% + 0.5A, compliant with high-precision requirements of power industry
Sampling Period	1ms, fully reproduces transient waveform fluctuations of current
Sensor Type	Split-core clamp-on current transformer, live-line installation without power cut-off
Insulation Withstand Level	≥ DC 10kV / 1min, adaptable to strong electromagnetic interference on HV sites
Communication Modes	4G wireless transmission as standard; Ethernet, RS485 optional
Supported Protocols	MODBUS, IEC 61850 (universal power industry communication standards)
Power Supply Modes	3 options: Solar + lithium battery power supply, CT inductive energy harvesting, AC/DC 220V input
Operating Ambient Temperature	-40℃ ~ +70℃, stable operation under extreme cold & high-temperature outdoor environments
Ingress Protection Grade	IP68; both sensors and terminals work long-term under humid, dusty and immersed outdoor conditions
Enclosure Material	Anti-corrosion non-eddy current special material, eliminates eddy current effect to guarantee measurement accuracy

Application Purpose & Installation Guide

Main Purposes

Continuously monitor amplitude and waveform of grounding current on HV cable metal sheath; detect hidden faults such as multi-point grounding and damaged sheath insulation, and warn against cable overheating & insulation aging risks in advance.
Realize anti-theft monitoring for grounding wires, cross-bonding cables and grounding boxes; send location-marked alarms once theft happens to reduce loss of cable accessories.
Replace periodic manual patrol inspection; auto-generate full-cycle current reports to support cable residual life assessment and condition-based maintenance arrangement.
Connect to integrated cable tunnel monitoring system, interlock with temperature and partial discharge monitoring equipment to build a complete full-link cable safety monitoring system.

Installation Steps

Site Survey: Confirm grounding point positions, grounding cable specifications, on-site power & communication conditions, and layout installation positions for sensors and acquisition terminals.
Sensor Mounting: Clamp the split-core current sensor tightly around the grounding cable, avoid dislocation and looseness; keep sensors away from strong electromagnetic interference sources.
Terminal Fixation: Install the acquisition terminal on waterproof brackets near grounding boxes, complete fastening and waterproof sealing treatment.
Wiring & Commissioning: Connect signal cables between sensors and terminals, switch on power supply, configure communication parameters for the background platform and finish data upload testing.
Threshold Setting: Set early warning thresholds according to rated cable load current. Normally, sheath grounding current shall be less than 100A, and the ratio of sheath current to cable load current shall not exceed 20%.
Trial Operation: Run the system continuously for 24 hours. Complete acceptance and delivery after verifying stable data transmission and accurate alarm logic.

Standard Packing List

Split-core sheath grounding current sensors (quantity customized per monitoring points)
1 set of sheath circulating current acquisition host terminal
1 set of 4G wireless communication module
1 set of solar power assembly (with lithium battery, optional for solar-powered version)
1 set of CT inductive power harvesting unit (optional for CT-powered version)
Shielded signal connecting cables
Outdoor waterproof mounting brackets & bolt kits
Product specification & installation commissioning manual
Factory test report and certificate of conformity
Authorized account for cloud background monitoring platform
Complete installation tool kit

FAQ – Cable Sheath Grounding Current Monitoring

Q1. What is the purpose of Cable Sheath Grounding Current Monitoring?

A1. It provides 24/7 continuous monitoring of circulating current on high-voltage cable metal sheaths. The system early detects multi-point grounding, sheath insulation damage and grounding wire theft, avoids cable overheating & insulation aging, and ensures reliable power grid operation.

Q2. What kinds of cable faults can this system detect?

A2. It identifies abnormal sheath current resulting from failed cross-bonding systems, multi-point grounding, broken grounding cables, stolen grounding accessories and outer sheath deterioration. It also sends instant anti-theft alarms once grounding components are cut or stolen.

Q3. Do we need to cut off power supply during installation?

A3. No power outage is required. Split-core clamp sensors support live-line non-intrusive installation. The original cable grounding structure and primary wiring will not be altered, causing no interference to the power grid.

Q4. What power supply methods does the terminal support?

A4. Three optional power solutions are available: solar & lithium battery off-grid power supply, CT inductive power harvesting from live cables, and AC/DC 220V mains input, suitable for all outdoor field conditions.

Q5. Which voltage levels of power cables are applicable?

A5. The system fits 6.6kV, 35kV, 110kV, 220kV and higher single-core HV power cables equipped with cross-bonding grounding systems.

Q6. How to view monitoring data and receive fault alarms remotely?

A6. Monitoring data is uploaded to the cloud platform via standard 4G wireless network; Ethernet and RS485 communication are optional. Users can check real-time curves, historical data and alarm messages on computers and mobile phones anytime.

Q7. What are the measurement precision parameters of the device?

A7. The sensitivity is ≤±0.1A, and measurement accuracy is reading ×1% + 0.5A. It can capture tiny current variations to discover minor hidden cable faults in advance.

Q8. Can the equipment run stably in harsh outdoor environments?

A8. Absolutely. Both sensors and terminals feature IP68 waterproof and dustproof rating, with an operating temperature range of -40℃ ~ +70℃, adapting to high humidity, dusty, freezing and rainy outdoor scenarios.

Q9. Does the monitoring system need regular daily maintenance?

A9. Built-in self-diagnosis function automatically checks power supply, communication links and hardware running status. The device is nearly maintenance-free, effectively cutting on-site inspection costs.

Q10. What communication protocols does the system comply with?

A10. It supports MODBUS and IEC 61850 universal power industry protocols, enabling seamless docking with cable tunnel integrated monitoring systems and smart grid platforms.

Q11. What is the difference between sheath current monitoring and partial discharge monitoring?

A11. Partial discharge monitoring checks internal main insulation defects of cables, while sheath current monitoring supervises the health of the metal sheath grounding system. The two systems work together to realize comprehensive cable condition monitoring.

Q12. Can you provide customized monitoring solutions?

A12. Yes. We can customize monitoring channels, communication modes, alarm thresholds and platform functions according to customers’ actual cable layout and project demands.

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