The Remote Oil & Winding Temperature Indicator is an important monitoring instrument used in oil-filled power and distribution transformers to measure and display both the top oil temperature and winding temperature from a remote location. Monitoring transformer temperature is critical for safe and efficient operation because excessive heat can damage insulation, reduce transformer performance, and significantly shorten equipment life.
Transformers generate heat during normal operation due to electrical losses in the core and windings. The insulating oil absorbs this heat and carries it to the cooling system, typically consisting of radiators or cooling fins. If the temperature rises above safe operating limits, it can cause insulation degradation and potential transformer failure. A Remote Oil & Winding Temperature Indicator helps prevent such situations by continuously monitoring these critical temperature parameters.
 
Unlike local temperature indicators installed directly on the transformer, remote indicators allow temperature readings to be displayed in a control panel or control room located at a safe distance from the transformer. This allows operators to monitor transformer temperature conditions easily without approaching high-voltage equipment.
Oil Temperature Monitoring
 
The Oil Temperature Indicator (OTI) measures the temperature of the transformer’s top oil. A temperature sensing bulb is installed in the transformer oil pocket, which detects changes in oil temperature during transformer operation. The temperature variation is transmitted to the indicator, providing a clear and accurate reading of the transformer oil temperature.
Monitoring the top oil temperature is essential because it reflects the overall thermal condition of the transformer. High oil temperature may indicate overload conditions, cooling system problems, or abnormal transformer operation.
Winding Temperature Monitoring
 
The Winding Temperature Indicator (WTI) provides an indication of the hottest point inside the transformer winding. Since direct measurement of winding temperature is not always possible, the indicator uses a thermal simulation technique.
A heater element connected to the transformer current transformer (CT) simulates the heating effect of the winding. This combined with the oil temperature measurement provides an accurate representation of the winding hot-spot temperature, which is one of the most critical parameters for transformer protection.
 
Key Features
Remote Oil & Winding Temperature Indicators are designed to provide reliable monitoring in demanding electrical environments.
• Accurate oil and winding temperature indication
• Remote monitoring from control panels or control rooms
• Adjustable alarm and trip contacts
• Clear and easy-to-read dial display
• Durable construction for substation environments
• Long service life with minimal maintenance
• Suitable for power and distribution transformers
• Reliable performance in industrial and utility installations
These features make the device an essential part of transformer monitoring and protection systems.
 
Applications
Remote Oil & Winding Temperature Indicators are widely used in many electrical installations including:
Electrical Substations
Monitoring temperature of power transformers.
Power Generation Plants
Ensuring safe transformer operation in power stations.
Industrial Power Systems
Used in factories and heavy industries where transformers operate continuously.
Utility Distribution Networks
Installed in distribution transformers for reliable temperature monitoring.
Renewable Energy Projects
Used in transformers installed in solar and wind power plants.
Importance in Transformer Protection
Temperature is one of the most critical parameters affecting transformer life and reliability. Continuous monitoring of oil and winding temperatures allows operators to detect abnormal conditions early and take corrective action before serious faults occur.
Alarm and trip contacts in the indicator can activate warning systems or protective relays when temperature exceeds preset limits, helping prevent overheating and equipment damage.
By providing accurate monitoring and remote indication capability, the Remote Oil & Winding Temperature Indicator helps improve transformer protection, operational safety, and long-term reliability of electrical power systems.