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The power transformer is a static electrical appliances, which is composed of two or more windings around the same iron core, winding by the alternating magnetic flux interlinkages between its function is the one kind another level of voltage and current levels of voltage and current into the same frequency, but also change the number of phases, impedance and phase; transformer types are generally divided into the power transformers and special transformers, the former is the transmission and distribution power system The important equipment, by end-use, step-up transformers, step-down transformer, distribution transformers and transformer in; by the structure, two-winding transformer, three winding transformers and self-coupling transformer; number of phases, single-phase transformers, three-phase transformers and polyphase transformers.

    The power transformer is the main equipment of power system transmission and distribution of electricity. Power transformers, high voltage of the grid to reduce direct use 6000 volts (V) or 380 volts (V) voltage, power supply to electrical equipment.

    Overload or short circuit, such as the power transformer internal insulation or insulation oil will heat or spark the role of decomposition, expansion as well as gasification, a sharp increase in the power transformer internal pressure may cause the explosion of the transformer casing, a large number of insulating oil spray combustion The oil flow will further expand the fire hazard.

    Fire explosion in the power transformers run to pay attention to:
    (1) can not overload the run: long-term overload operation will cause the coil heat, so that insulation is gradually aging, causing a short circuit.
    (2) regular testing of insulating oil: the oil should be checked regularly, failed oil should be replaced, or take other measures.
    (3) to prevent damage to the transformer core insulation aging, the core long-term fever caused by insulation aging.
    (4) to prevent inadvertent destruction due to repair insulation, if found scrape injury, on the timely processing.
    (5) to ensure good contact wire, poor contact a local overheating.
    (6) to prevent lightning strikes, transformer due to insulation breakdown and burned.
    (7) Short circuit protection: transformer coil or load short circuit protection system failure or the protection of value is too large, it may be burned transformer. To do this you want to install a reliable short-circuit protection.
    (8) protection of a good grounding.
    (9) ventilation and cooling: If the power transformer coil wire Class A insulation, the insulator paper and cotton yarn. Temperature is increased by 8 ° C insulation life to be reduced by about half; the normal temperature of the transformer to run below 90 ℃, the life span of about 20 years; if the temperature rose to 105 ° C, the life expectancy of seven years. Power transformer operation, to maintain good ventilation and cooling.

Safe operation and service life of dry-type transformers, depends largely on the safety and reliability of the transformer winding insulation. Winding temperature exceeds the insulation withstand temperature, insulation damage, is one of the main cause of dry-type transformer is not working properly, so the transformer operating temperature monitoring and alarm control is very important, this series of temperature on the TTC-300 system for an Introduction.

    Fan automatic control: (1) embedded in low-voltage winding hottest at the Pt100 thermistor temperature resistance measurements take the temperature signal. Dry-type transformer load increases, the increase in operating temperature, when the winding temperature reaches 110 ℃, the system automatically starts the cooling fan; when the winding temperature as low as 90 ° C, the system automatically stops the fan.

    (2) over-temperature alarm trip: PTC nonlinear embedded in low-voltage winding temperature thermal resistance acquisition winding or core temperature signal. Dry-type transformer winding temperature continues to rise and reached 155 ° C, the system output over temperature alarm signal; if the temperature continues to rise up to 170 ° C, dry-type transformers can not continue to run, are required to protect the secondary loop conveyor overtemperature trip signal should enable the rapid tripping of dry-type transformers.

    (3) The temperature display system: embedded in low-voltage winding Pt100 thermal resistance measurement to take the temperature value directly display the temperature of windings of each phase (three-phase inspection and the maximum display and can record the highest temperature), the maximum temperature to 4 ~ 20mA analog output.

    For transfer to the distance (distance up to 1200m) computer can be added with a computer interface, a transmitter can simultaneously monitor up to 31 sets of dry-type transformers. System over-temperature alarm, trip also can be Pt100 thermal sensor resistance signal action to further improve the reliability of temperature control and protection system.