Switchgear Wireless Temperature Monitoring System: Composition, Configuration and Functions

System Model: GWWT-MS

• The GWWT-MS Wireless Temperature Monitoring System is a professional online temperature monitoring solution designed for 0.4 kV to 230 kV switchgear and GIS equipment. It adopts LoRa, 433 MHz or 2.4 GHz wireless communication technologies to replace conventional secondary hardwiring. Traditional wired installation in high-voltage live areas suffers from insulation risks, complicated construction and high retrofitting workload. By applying wireless sensors mounted directly on live components, the system achieves complete galvanic isolation between the HV and LV sides. With wiring-free installation, it is fully compatible with both new-built and in-service switchgear assets.
• Operating reliably under strong electromagnetic interference environments, the system continuously collects real-time temperature data of busbars, breaker contacts, cable terminals and other critical hot spots, as well as cabinet internal temperature and humidity parameters. It supports 24/7 online condition monitoring, local alarm output, and remote data transmission to SCADA and substation protection & control systems. The system provides early warning of overheating faults and promotes maintenance transformation from passive breakdown repair to active predictive maintenance. It is widely applicable in substations, ring main units, data centers, industrial and mining distribution rooms, photovoltaic power stations and wind farm booster stations.
• The system adapts to mainstream indoor switchgear such as KYN28 and XGN series. For 230 kV voltage levels, it is mainly deployed for temperature monitoring of GIS and HGIS equipment contacts. The overall solution adopts a standard three-layer architecture: wireless perception layer, local data aggregation layer, and remote monitoring platform layer, realizing accurate online hot spot monitoring and reliable overheating early warning with minimized secondary construction work.

1. System Composition

• The GWWT-MS system consists of three core layers: Perception Layer (wireless temperature sensors), Local Aggregation Layer (wireless temperature acquisition and HMI units), and Station Control Layer (back-end monitoring system).

1.1 Perception Layer – Wireless Temperature Sensors

• Sensors are installed on switchgear and GIS key live parts to collect real-time hot-spot temperature data. The system adopts three mainstream sensor models for different working conditions.

The system adopts LoRa and 433 MHz short-range wireless communication technologies, featuring strong signal penetration through enclosures and high anti-interference capability, ensuring stable data transmission in high-voltage electromagnetic environments.

1.2 Local Aggregation Layer – Wireless Temperature Monitoring Host

The aggregation unit receives, processes and uploads all wireless sensor data, serving as the core data transmission and local control unit of the GWWT-MS system.

One aggregation host can cover multiple switchgear cubicles. For fully enclosed GIS equipment, external high-gain antennas are deployed to mitigate signal attenuation caused by metal shielding.

1.3 Station Control Layer – Back-End Monitoring System

• Hardware: Industrial server / Industrial PC
• Software: Dedicated monitoring and configuration software compatible with the GWWT-MS system
• Main functions: Real-time data visualization, temperature trend curve analysis, over-temperature alarm judgment, event logging, data statistics and report generation. It can be seamlessly integrated with substation SCADA and P&C (protection & control) systems.

2. Typical Engineering Configuration Schemes

Scheme A: Standard Configuration for 10 kV Distribution Switchgear

Applicable to conventional KYN28-12 indoor switchgear:

• A/B/C three-phase busbar joints: 3 sets of GWWT-S-P;
• Breaker upper and lower contacts: 3 sets of GWWT-S-P;
• Cable termination points: 3 sets of GWWT-S-P;
•  Cabinet equipped with wireless temperature and humidity sensor;
• One GWWT-CU is configured for every 8 to 12 switchgear cubicles; GWWT-HMI is adopted if local display is required;
• The back-end platform accesses the station SCADA system and completes over-temperature threshold configuration.

Scheme B: Low-Current Working Condition Configuration

• For switchgear with long-term operating current below 50 A, replace passive sensors with GWWT-S-A. GWWT-S-PM shall be adopted for confined installation spaces, while other configurations remain unchanged.

Scheme C: High-Voltage GIS Configuration (Up to 230 kV)

• High-insulation grade GWWT-S-P and GWWT-S-PM are applied for GIS bushings and disconnector contacts. GWWT-CU/GWWT-HMI is installed in the protection cubicle with external antenna accessories to ensure stable wireless transmission.

Key Configuration Notes

•  The number of wireless sensors shall not exceed the maximum capacity supported by the GWWT-CU/GWWT-HMI. Signal repeaters shall be deployed in cases where severe signal attenuation is observed.
• Passive sensors are applicable for working current above 50 A; active sensors shall be adopted for low-current loops.
• All high-voltage sensors comply with the applicable insulation and partial discharge test standards for their respective voltage levels.
• The system supports mainstream industrial protocols such as IEC 61850 and Modbus for flexible interfacing with substation automation systems.
• Dry contact alarm signals can be transmitted to substation telecontrol (RTU) systems.

3. Core Functions of Each Module

3.1 Wireless Sensor Module

• GWWT-S-P realizes battery-free and maintenance-free temperature monitoring for conventional current loops, effectively preventing overheating faults caused by loose bolted connections and increased contact resistance. GWWT-S-A solves the temperature collection problem under low-current working conditions. GWWT-S-PM adapts to compact and narrow equipment structures. The temperature and humidity sensor monitors cabinet condensation risks and links with dehumidification equipment to prevent insulation flashover faults.

3.2 Data Aggregation Host (GWWT-CU / GWWT-HMI)

• The host centrally collects and preprocesses all temperature data, provides local over-temperature detection and audible & visual alarm outputs. It performs protocol conversion between the proprietary wireless protocol and standard industrial protocols to ensure compatibility with upper automation systems. It supports offline data caching and automatic retransmission upon network recovery. Meanwhile, it can be used for linkage control of on-site dehumidifiers and ventilation equipment.

3.3 Back-End Monitoring Platform

• Unified online monitoring of temperature data of all switchgear and GIS intervals. It realizes intelligent functions such as real-time alarm, historical trend tracing, fault event recording and automatic report generation, providing reliable data support for equipment operation analysis and maintenance arrangement.

4. Overall System Advantages and Functions

• Wiring-Free Online Monitoring: The GWWT-MS system completely abandons complex secondary wiring, greatly reducing construction complexity and outage-related retrofitting workload, and is especially suitable for in-service equipment upgrades and retrofits.
• Early Warning of Overheating Abnormal Risks: It provides 24/7 uninterrupted monitoring of critical hot spots, accurately captures early abnormal temperature changes, and avoids equipment burnout and short-circuit accidents caused by long-term overheating.
• Support Condition-Based Maintenance: It replaces traditional time-based maintenance with predictive maintenance strategies driven by real-time temperature data, reduces unnecessary outage maintenance, and improves operational efficiency.
• Strong System Compatibility: The GWWT-MS wireless temperature monitoring system can operate independently or be seamlessly integrated with existing SCADA and P&C platforms, which is highly adaptable for both new and retrofit power distribution projects.
• Note: Special customized models including outdoor magnetic mounting, dual-mode active-passive and solar-powered sensors are optional for special working conditions and not included in the standard GWWT-MS system configuration.