Continuous Thermal Monitoring (CTM): A Breakthrough in Safety & Maintenance to International Standards 2025–2026

1. What is Continuous Thermal Monitoring (CTM)?

Continuous Thermal Monitoring (CTM) is an advanced system designed to ensure optimal performance and safety for industrial operations that rely on electrical power. The technology uses dedicated sensors installed at critical equipment and components to measure temperature variations in real time.

This continuous stream of data is essential for maintaining the integrity and efficiency of the overall system. Grid operators and facility engineers no longer have to guess equipment health between manual inspection intervals spaced months or even years apart.

2. How Does a CTM System Work?

An industrial CTM system operates on a 5-step closed-loop lifecycle, bridging physical sensing on energized assets to automated maintenance decision-making:

Trend Analysis: Accumulated data over time helps identify points at risk of failure and supports the strategic transition to Condition-Based Maintenance (CBM) and Reliability-Centered Maintenance (RBM).

3. Recommendations for CTM Application from the Perspective of International Technical Standards (2025–2026)

The adoption of technologies such as CTM is becoming increasingly important and urgent as international standards in the power industry become more stringent and are continuously updated:

IEEE 2969-2025 International Standard

Issued in 2026, IEEE 2969-2025 (IEEE Guide for Continuous Thermal Monitoring of Switchgear and Motor Control Centers up to 52 kV) provides formal guidance on continuous thermal monitoring methods for switchgear and motor control centers.

CIGRE Technical Brochure 999

Published by Joint Working Group B3.D2.62 (August 2026, ISBN 978-2-85873-704-8), CIGRE TB 999 (Lifelong Supervision and Management of Substations by Use of Sensors, Mobile Devices, Information and Communication Technologies) recommends continuous thermal monitoring systems as an indispensable part of a condition monitoring and lifecycle management solution for substation assets.

Continuous temperature data collection at critical locations—such as transformers, connections, busbars, cables, and switchgear—helps detect overheating, hot spots, and abnormal signs of degradation at an early stage. Measurement data should be integrated with SCADA/asset monitoring systems for trend analysis, early warning, and condition-based maintenance, thereby improving operational reliability, reducing outage risks, and optimizing asset management throughout the equipment lifecycle.

Furthermore, in Table 2.8-1, CIGRE TB 999 explicitly identifies the energy harvesting thermal sensor as the recommended mitigation technology for both transformer and circuit-breaker thermal risks.

NFPA 70B, Standard for Electrical Equipment Maintenance – 2026 Edition (USA)

Under NFPA 70B (2026 Edition), electrical equipment condition should be maintained through a systematic maintenance program that combines condition monitoring with early detection of abnormal conditions.

4. How Does CTM Differ from Infrared (IR) Thermal Camera Inspection?

Many utilities and industrial plants historically relied on periodic infrared inspection using handheld thermal cameras. However, periodic infrared inspection has several critical limitations:

• Intermittent Snapshot Nature: Thermal scans capture temperature only at a single moment in time (e.g., once every 3 to 12 months). If the electrical circuit is lightly loaded during inspection, severe contact resistance issues remain completely concealed.
• Physical Blind Spots: In metal-enclosed switchgear (Metal-clad Switchgear), bolted busbar joints behind phase barriers, partition sheets, or insulation boots cannot be seen by an external infrared camera.
• Personnel Safety Hazards: Technicians must approach energized medium- and high-voltage equipment, frequently opening enclosure doors and exposing personnel to fatal Arc Flash and electrocution hazards.

In contrast, CTM provides 24/7 system monitoring, eliminates blind spots, and does not require personnel to directly open electrical enclosures, thereby enhancing safety and providing accurate trend data in line with the recommendations of IEEE 2969-2025.

Periodic IR Inspection (Severe Blind Spots)

Thermal cameras only capture exposed surfaces line-of-sight; they cannot see through phase barriers, insulation boots, or inside enclosed breaker compartments.

24/7 CTM System (Direct Contact Measurement)

VTI wireless sensors clamp directly onto busbars and contact points, transmitting temperature data continuously without opening cabinet doors.

Figure 3: CTM eliminates blind spots in monitoring the temperature of contact points inside enclosed electrical cabinets.