Winding temperature exceeds the temperature of the insulation damage to insulation resistance, leading to one of the main reasons for the dry type transformer is not working properly. Therefore, the safe operation of dry type transformer and the service life of the, to a large extent depends on the dry type transformer winding insulation safety reliable.
For dry type transformers operating temperature monitoring and alarm control is very important:
1, temperature display system: through the pre buried in low-voltage winding of Pt100 thermal resistance measured temperature value, directly showing the winding temperature (maximum three-phase inspection and display, and recorded its highest temperature), the highest temperature to 4 ~ 20mA analog output, if need to transfer to the distant rolling machine (distance up to 1200m) computer, and equipped with computer interface and a transmitter up and monitoring of 31 transformers. The over temperature alarm, trip can also be PT100 thermal sensor resistance signal action bending machine, to further improve the reliability of protection system for temperature control.
2, over temperature alarm and tripping: embedded in low-voltage winding through the PTC thermistor temperature resistance non-linear winding or core temperature signal acquisition. When the dry type transformer winding temperature continues to rise, if it were up to 155 DEG C, the system output over temperature alarm signal; if temperatures continue to rise up to 170 DEG C, transformers have been unable to continue operation. Must be to the secondary circuit conveying overheat trip signal, should make the transformer tripping rapidly.
3 automatic control fan: Pt100 thermistor temperature resistance low-voltage windings embedded in the heat through pre measured temperature signals. Transformer load increase bending machine, operating temperature increases, when the winding temperature of 110 DEG C, the system automatically start a cooling fan; when winding temperature low to 90 DEG C, the system will automatically stop fan.