Transformer overload means that the transformer output current exceeds its rated current due to the increase in load during operation. Overload is a serious risk for transformers and may cause serious consequences such as equipment damage and electrical fires. Therefore, it is crucial to detect the signs of transformer overload in time and take corresponding measures.
Signs of transformer overload
1. Transformer heating
When overloaded, the output current exceeds the rated current, causing the transformer to heat up and the temperature to rise continuously. When the temperature rises to a certain extent, it may damage the insulation material of the transformer and even cause faults such as short circuits.
2. Noise increases
Overload will cause the windings of the transformer to vibrate due to the increase in current, resulting in increased noise. In severe cases, the noise will be very obvious.
3. Output voltage reduction: Overload will cause the output current to be too large, which reduces the voltage of the transformer winding. And the output voltage will be unstable, which may affect the normal operation of the load equipment.
4. Smoke and sparks: When the overload is severe, the windings will be locally overheated due to excessive current, which may cause the windings or transformer oil to burn, releasing smoke and sparks.
Causes of transformer overload
1. Sudden increase in electricity demand
For example, during the hot summer, the concentrated use of refrigeration equipment such as air conditioners may cause a sharp increase in the power load of the local power grid, causing the transformer to overload.
2. Improper transformer capacity selection
When selecting a transformer, if the future growth demand for electricity consumption is not fully considered, or the prediction of the electricity load is inaccurate, the transformer capacity may be too small to meet the actual electricity demand.
3. Power system failure
For example, when a power system fails, it may cause uneven local power distribution, causing some transformers to bear too heavy a burden.
4. Poor heat dissipation
If the heat dissipation system of the transformer fails or is improperly designed, it may cause the transformer to be unable to dissipate the heat generated in time during operation. This causes the transformer temperature to rise, and in turn causes overload problems.
Hazards of transformer overload
1. Accelerate equipment aging
Overload will cause the internal temperature of the transformer to rise, accelerate the aging process of insulation materials, windings and other components, and shorten the service life of the transformer.
2. Cause equipment failure
Long-term overload operation may cause transformer winding overheating, insulation breakdown and other failures. In severe cases, overload may cause safety accidents such as fire.
3. Affect power supply reliability
Transformer overload may cause it to fail to operate normally, thereby affecting the power supply reliability of the entire power system. In the case of severe overload, it may even cause transformer damage, resulting in serious consequences such as long-term power outages.
Control methods for transformer overload
For the control methods of transformer overload, the commonly used methods are as follows:
1. When abnormal heating of the transformer is found, it should be stopped immediately for inspection, and the abnormal electrical equipment in the substation should be eliminated.
2. Use dampers or other control devices to reduce the overload degree of the transformer. When the transformer is overloaded, start the compensation device in time to reduce the overload current.
3. For transformers with excessive no-load current, you can consider increasing the transformer capacity or upgrading the transformer.
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