Dry-Type vs Oil-Immersed Transformer Temperature Controller
The oil and winding temperatures within a transformer affect the performance and lifespan of insulation materials—and consequently the lifespan of the transformer itself—or can even directly lead to equipment failure; therefore, real-time monitoring of internal temperatures is essential. Depending on the specific component being monitored, transformer temperature controllers are categorized into oil-temperature controllers (for oil-immersed transformers) and winding-temperature controllers (for dry-type transformers).
To assist panel builders and transformer manufacturers in making efficient selection decisions, this article compares the differences between temperature controllers for dry-type transformers and those for oil-immersed transformers.
What is Blue Jay Dry-type transformer temperature controller?
Dry-type transformers commonly use cast-resin or other solid insulation systems, with heat dissipated through air cooling. Because winding temperature is a key indicator of thermal stress, direct winding temperature measurement is important for detecting overheating and managing cooling operation.
The Blue Jay TWSK-G uses a three-phase winding temperature sensor arrangement, with three-wire sensors supplied as standard and four-wire sensors available as an option. Its main functions include:
Three-Phase Winding Monitoring: Displays winding temperatures for the three phases.
Automatic and Manual Fan Control: Controls cooling fans according to configured operating conditions.
Over temperature Alarm and Trip: Provides alarm and trip outputs when preset temperature thresholds are reached.
Sensor Fault Detection: Detects sensor open circuits and other sensor malfunctions.
Temperature Records: Records maximum temperature and supports temperature logging when power is lost.
Communication and Integration: Supports RS485 Modbus RTU, with optional 4–20 mA output and core temperature monitoring.
The TWSK-G is suitable for cast-resin transformers, industrial dry-type transformers, and air-cooled transformer installations where winding temperature monitoring and cooling fan control are required.
What is Blue Jay oil-immersed transformer temperature controller?
In oil-immersed transformers, insulating oil provides both electrical insulation and heat transfer. Oil temperature monitoring helps identify abnormal thermal conditions and supports the management of transformer cooling.
The TWSK-Y uses an armored PT100 oil temperature sensor with a three-wire connection and a cable length of up to 20 m. Its principal features include:
Real-Time Oil Temperature Monitoring: Measures oil temperature over a range of −40 to 150°C.
PT100 Temperature Sensing: Uses a three-wire RTD sensor for accurate temperature measurement.
Automatic and Manual Cooling Control: Supports cooling fan operation according to configured temperature conditions.
Over temperature Alarm and Trip: Provides outputs for temperature-related alarm and protection.
Remote Monitoring: Supports RS485 Modbus RTU communication.
Additional Outputs: Provides relay outputs and an optional 4–20 mA analog output.
Blue Jay
The TWSK-Y is suitable for distribution transformers, oil-immersed power transformers, and industrial transformer cooling systems.
Dry-Type vs Oil-Immersed Transformer Temperature Controller
Although both controllers monitor temperature and support thermal protection, they differ in their measurement targets, sensor installation, and application requirements.
Comparison | TWSK-G Dry-Type | TWSK-Y Oil-Immersed |
Transformer type | Dry-type | Oil-immersed |
Primary measurement | Three-phase winding temperature | Transformer oil temperature |
Sensor | Three-phase winding temperature sensors | Armored PT100 oil sensor |
Standard sensor connection | Three-wire; four-wire optional | Three-wire |
Temperature range | Model specification: −30 to 200°C | −40 to 150°C |
Cooling control | Manual / automatic fan control | Manual / automatic fan control |
Alarm and trip | Supported | Supported |
RS485 Modbus RTU | Supported | Supported |
Optional 4–20 mA output | Available | Available |
Conclusion
Choosing between a dry-type and an oil-immersed transformer temperature controller starts with the transformer construction and the required measurement target. The TWSK-G is designed for three-phase winding temperature monitoring and cooling control in dry-type transformers, while the TWSK-Y focuses on oil temperature monitoring and cooling control in oil-immersed transformers.
For panel builders and transformer manufacturers, selecting the appropriate controller and sensor arrangement helps improve temperature monitoring, support timely over temperature protection, and simplify integration into transformer control panels. Before ordering, confirm the sensor configuration, temperature thresholds, cooling control requirements, alarm and trip outputs, and communication options against the transformer specifications.
