09,22,2026 16 views
1. Strengthen daily maintenance and regular testing
According to the division of labor among management personnel, in addition to regularly carrying out transformer work, I also require management personnel to strengthen daily work and allocate responsibilities. The key inspection contents include:
1. Observe the appearance. The main inspection is to check for oil leakage, smoking or emission of parts. The transformer casing is not tightly welded or the rubber gasket is not firm, which may cause transformer leakage. If the oil level is too low, insulation protection will be lost, resulting in discharge between conductive parts or between conductive parts and the casing, and in severe cases, the transformer may be burned out. Therefore, faults should be eliminated and oil should be replenished in a timely manner to ensure that the oil level remains at 1/4 to 3/4 of the oil standard. For loose parts, poor contact, or even discharge, the transformer's drop protection should be promptly cut off to eliminate potential hazards.
2. Check the moisture absorbing device. When the volume of transformer oil expands and contracts due to changes in load or ambient temperature, it forces the gas in the oil storage tank to breathe through the moisture absorbing device to remove debris and moisture from the air, thereby maintaining the insulation strength of the transformer oil in the transformer.
3. Regularly inspect the casing. Sleeve is a component insulation composed of conductive tubes and sleeve type insulation. In the case of a transformer, it is used to lead its internal windings into electrical connections with the power system or electrical equipment.
1) Check if the oil level in the casing is normal
2) Check whether the surface of the casing is clean, whether there are cracks, damages, discharge points, and other phenomena.
3) Check if the connection between the sleeve terminal and the busbar is loose.
4) Check if the oil level of the oil paper capacitor sleeve is normal.
5) Check if the cover of the oil paper capacitor sleeve is loose.
4. Listen to the sound. The normal operation of a transformer will produce a uniform and subtle buzzing sound, and the sound will change when the transformer experiences faults with different characteristics. At this point, measures should be taken based on the on-site situation to identify the cause of the malfunction.
5. It is necessary to inspect the oil and dust on the high and low voltage casings, promptly clean and remove greasy dust, dirt, and arcing discharge materials. When the climate is humid or rainy, if it causes a short circuit between the casings, the high voltage fuse will melt and the matching will be ineffective. I want people to clean at least once every two months.
6. Observe the oil color and regularly check the oil temperature, especially in cases of large load changes, large temperature differences, and adverse weather conditions, increase the frequency. The top oil temperature of oil immersed distribution transformers in operation should not exceed 95 ℃.
7. Shake and measure the insulation resistance of the transformer, check if the wires are secure, and pay special attention to whether the low-voltage socket connection is good and whether the temperature is abnormal.
8. Strengthen the measurement of power load. During peak electricity consumption periods, strengthen the load measurement of each distribution transformer, increase the number of measurements if necessary, and adjust distribution transformers with unbalanced three-phase currents in a timely manner to prevent excessive neutral current from burning out the leads and causing damage. User's equipment and distribution transformers. The connection group is Yyn0, which not only requires the use of one or two phase power sources, but also the three-phase load should be balanced as much as possible. The neutral line current should not exceed 25% of the rated current on the low voltage side, in an attempt to prevent the distribution transformer from overloading and operating towards the load.
9. Regularly check and replace one or two fuses. It is strictly prohibited to use aluminum wire to replace fuses. Primary fuse protection system, secondary fuse protection transformer.
2、 Prevent external damage
1. Reasonably select the installation location of the distribution transformer, which should be as close as possible to the load center and control the power supply radius within 0.5km. Meanwhile, try to avoid installing equipment in lightning or low-lying water areas as much as possible. Due to its location in the county town, there are many transformers at the intersection. In order to reduce car collisions with the tower, anti-collision signs are pasted along the tower.
2. Try to avoid installing low-voltage instrument boxes on distribution transformers. Due to prolonged operation, the glass of the meter box is damaged or the low-voltage pile head of the transformer cannot be replaced in a timely manner. More than 95% of public distribution transformers are equipped with JP cabinets, which play a good role in protecting the safe operation of transformers.
3. It is not allowed to adjust the tap changer without permission. If the tap changer is not adjusted properly and a phase to phase short circuit occurs, it may burn out the distribution transformer.
4. Install insulation covers at the high and low voltage ends of the distribution transformer to prevent natural disasters and external damage. Install high and low voltage insulation covers in narrow residential areas and forest areas where animals frequently enter and exit, to prevent distribution transformers from falling and burning due to falling onto their wiring stacks.
5. Regularly cut off the circuit channels to prevent branches from contacting wires and causing low voltage short circuits and burning out distribution transformers.
3. Precautions for use
1. Prevent transformer overload operation: If overloaded operation is carried out for a long time, the coil will be heated, the insulation layer will gradually age, and short circuits will occur between wire boxes, phases, or the ground as oil decomposition;
2. Prevent aging and damage of transformer core: Aging of core insulation or damage to clamping bolt sleeves can cause large eddy currents in the core, and long-term heating of the core can lead to insulation aging;
3. Prevent careless maintenance of insulation damage: When maintaining the transformer core, attention should be paid to protecting the coil or insulation sleeve. If any scratches are found, please handle them promptly.
4. The unbalanced current of the low-voltage transformer shall not exceed 25% of the rated value; The voltage variation of the transformer power supply is allowed to be plus or minus 5% of the rated voltage.
5. Ensure good wire contact: Poor contact between the internal joints of the coil, poor contact between the connection points between the coils, resulting in poor contact between the bushing contact points on the high and low voltage sides and the support points on the tap changer. Switches will cause local overheating, insulation damage, short circuits, or open circuits. The high-temperature arc generated at this time will cause the insulation oil to decompose, producing a large amount of gas and pressure in the transformer. When the pressure exceeds the value protected by the gas circuit breaker without tripping, an explosion will occur.
6. Maintain good grounding: To use zero voltage protection for low voltage systems, conduct testing. The neutral point on the low voltage side of the transformer should be directly grounded. When this current is too high and the contact resistance is large, the node will experience high temperatures, igniting surrounding combustibles.
