1. Automatic control of the fan: the temperature signal is measured by the PT100 thermosensitive temperature resistance embedded in the hottest part of the low-voltage winding. The transformer load increases, the operating temperature rises, when the winding temperature reaches 110℃, the system automatically starts the fan cooling; When the winding temperature is low to 90℃, the system automatically stops the fan.
2. Over-temperature alarm and trip: the temperature signal of the winding or core is collected through the PTC nonlinear thermosensitive temperature measurement resistor embedded in the low-voltage winding. When the transformer winding temperature continues to rise, if it reaches 155℃, the system output overtemperature alarm signal; If the temperature continues to rise to 170℃, the transformer can not continue to operate, it is necessary to transmit the overtemperature trip signal to the secondary protection circuit, and the transformer should trip quickly.
3, temperature display system: through embedded in the low voltage winding Pt100 thermistor measured temperature value, direct display of each phase winding temperature (three-phase, according to the inspection and the maximum value and can record the highest temperature), the highest temperature can be in 4 ~ 20 ma analog output, if need to transport to the distance (distance of up to 1200 m) computer, can be added with computer interface, one transmitter, maximum 31 sets of transformer monitoring at the same time. The overtemperature alarm and tripping of the system can also be acted by the signal of PT100 thermosensitive sensor resistance, which further improves the reliability of the temperature control protection system.
According to the use of environmental characteristics and protection requirements, dry-type transformer can choose different shell. IP20 protective shell is usually used to prevent solid foreign bodies with diameter greater than 12mm and small animals such as rats, snakes, cats, birds and so on from entering and causing malignant faults such as short circuit and power failure, so as to provide a safety barrier for live parts. If the transformer is to be installed outdoors, the IP23 protective enclosure can be selected. In addition to the above IP20 protective function, it can also prevent water droplets within 60° of the vertical line from entering. But the IP23 shell will reduce the cooling capacity of the transformer, and attention should be paid to the reduction of its operating capacity when choosing.
Service