What Kind Of Tests Should Be Done On Oil-Immersed Transformers During Operation?
What kind of tests should be done on oil-immersed transformers during operation?
In order to ensure that the oil-immersed transformer can operate normally, the following tests should be carried out frequently: Temperature test. Whether the oil-immersed transformer is operating normally or not, the temperature is very important. The regulations stipulate that the upper oil temperature shall not exceed 85C (that is, the temperature rise is 55C). Generally, oil-immersed transformers are equipped with special temperature measuring devices. Load determination. In order to improve the utilization rate of oil-immersed transformers and reduce the loss of electric energy, it is necessary to determine the power supply capacity that the oil-immersed transformer can truly bear during the operation of the oil-immersed transformer. The measurement work is usually carried out during the peak period of electricity consumption in each season, and is measured directly with a clamp ammeter. The current value should be 70 to 80% of the rated current of the oil-immersed transformer. If it exceeds, it indicates overload and should be adjusted immediately. Voltage measurement. Regulations require that the voltage variation range should be within ±5% of the rated voltage. If it exceeds this range, taps should be used to adjust the voltage to the specified range. Generally, a voltmeter is used to measure the secondary coil terminal voltage and the terminal voltage of the end user respectively. Insulation resistance measurement. In order to keep the oil-immersed transformer in normal operation, the insulation resistance must be measured to prevent insulation aging and accidents.
When measuring, try to stop the oil-immersed transformer from running. Use a megometer to measure the insulation resistance value of the oil-immersed transformer. It is required that the measured resistance is not less than 70% of the previously measured value. When using a megohmmeter, the low-voltage coil can use 500 volts. voltage level. It has been theoretically confirmed that the voltage ratio between the primary coil and the secondary coil of the oil-immersed transformer is related to the ratio of turns between the primary coil and the secondary coil, which can be expressed by the following formula: primary coil voltage/secondary coil voltage = primary coil turns/secondary The number of turns in a coil indicates that the more turns, the higher the voltage. So it can be seen that the secondary coil is less than the primary coil, which is a step-down oil-immersed transformer. The opposite is a step-up oil-immersed transformer.