Temperature Control System For Dry-type Transformers

The safe operation and service life of dry-type transformers largely depend on the safety and reliability of the transformer winding insulation. When the winding temperature exceeds the insulation withstand temperature, causing insulation damage, it is one of the main reasons why the transformer cannot work normally. Therefore, monitoring the operating temperature of the transformer and its alarm control are very important.
⑴ Automatic fan control: The temperature signal is measured through the Pt100 thermistor temperature measuring resistor embedded in the hottest part of the low-voltage winding. As the load of the transformer increases, the operating temperature rises. When the winding temperature reaches 110°C, the system automatically starts the fan for cooling; when the winding temperature drops to 90°C, the system automatically stops the fan.
⑵ Over-temperature alarm and tripping: The winding or core temperature signal is collected through the PTC non-linear thermistor temperature measuring resistor embedded in the low-voltage winding. When the temperature of the transformer winding continues to rise, if it reaches 155°C, the system will output an over-temperature alarm signal; if the temperature continues to rise to 170°C, the transformer can no longer continue to operate, and an over-temperature trip signal must be sent to the secondary protection circuit to cause the transformer to Trip quickly.
⑶ Temperature display system: The temperature change value is measured through the Pt100 thermistor embedded in the low-voltage winding, and the temperature of each phase winding is directly displayed (three-phase inspection and maximum value display, and the historical maximum temperature can be recorded), and the maximum temperature can be recorded. The temperature is output as 4~20mA analog quantity and can be transmitted to a remote computer (distance up to 1200m) if needed.