Dry-type transformer temperature control system

The safe operation and service life of dry-type transformers depend largely on the safety and reliability of transformer winding insulation. The insulation damage caused by the winding temperature exceeding the insulation tolerance temperature is one of the main reasons for the failure of the transformer to work properly. Therefore, it is very important to monitor the operating temperature of the transformer and its alarm control.
⑴ Automatic fan control: The temperature signal is measured by the Pt100 thermistor embedded in the hottest part of the low-voltage winding. When the transformer load increases and the operating temperature rises, when the winding temperature reaches 110°C, the system automatically starts the fan 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 by the PTC nonlinear thermistor embedded in the low-voltage winding. When the transformer winding temperature continues to rise, if it reaches 155°C, the system outputs 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 tripping signal must be sent to the secondary protection circuit, which should cause the transformer to trip quickly.
⑶ Temperature display system: The temperature change value is measured by 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 highest temperature can be recorded). The highest temperature can be output as 4-20mA analog quantity, and if it needs to be transmitted to a remote computer (up to 1200m away)