Ranking of domestic manufacturers of three-phase o

Xuzhou three-phase oil immersed transformer domestic manufacturers ranking

voltage problem

reason: high voltage will make the transformer overexcited, and the sound will increase and be sharp. Xuzhou three-phase oil immersed transformer domestic manufacturers ranking_ [Pengcheng electric] directly and seriously affects the noise of the transformer

judgment method: first look at the low-voltage output voltage, not the voltmeter on the low-voltage cabinet, which only serves as an indication. Xuzhou three-phase oil immersed transformer ranks among domestic manufacturers_ [Pengcheng electric] should use a more accurate multimeter for measurement

solution: now the 10KV voltage in cities is generally high. According to the output voltage at the low voltage side, the tap gear should be placed in the appropriate gear at this time. On the premise of ensuring the quality of low-voltage power supply, Xuzhou three-phase oil immersed transformer ranks among the domestic manufacturers_ [Pengcheng electric] try to increase the high-voltage tapping direction (reduce the low-voltage output voltage) to eliminate the overexcitation of the transformer and reduce the noise of the transformer at the same time

inspection of transformer operation and maintenance this kind of new materials adopting PolyOne pultrusion molding process have achieved lightweight while maintaining the original problem of changing the stiffness

suspension potential

reason: the clamping channel steel, pressure nail bolt, pull plate and other parts of the transformer are sprayed with blue paint, and the contact of each part is not very good. Under the action of magnetic leakage field, the suspended potential discharge between each part produces a sound

judgment method: the suspended potential discharge makes a slight "squeak, squeak" sound, which can be heard only after careful listening. Users often mistakenly believe that the high voltage or low voltage of the transformer is discharging

solution:

1) this discharge will not affect the normal operation of the transformer

2) the paint at the place with poor contact can be scraped off during power outage maintenance, so that the parts of the transformer can be in good contact

the low-voltage line is grounded or short circuited

when the low-voltage line is grounded or short circuited, the measured value of the ear breaking rate D will make a roaring sound; The closer the short-circuit point is to the transformer, the more obvious the sound is; If the short-circuit point is close to the transformer, the transformer will make a loud and obvious sound

normal operation mode of transformer

① rated operation mode. Under the specified cooling conditions, the transformer can operate according to the nameplate specifications. The allowable temperature of oil immersed transformer during operation shall be checked according to the upper oil temperature. The upper oil temperature shall comply with the regulations of the manufacturer, but the maximum temperature shall not exceed 95 ℃. In order to prevent the transformer oil from deteriorating too fast, the upper oil temperature should not often exceed 85 ℃

the applied voltage of the transformer shall generally not exceed 105% of the rated value. At this time, the secondary side of the transformer can carry the rated current. In some cases, after testing or with the consent of the manufacturer, the applied voltage can be 110% of the rated voltage

② overload is allowed. The transformer can operate under normal overload or accident overload. Normal overload can be used frequently, and its allowable value is determined according to the load curve of the transformer, cooling conditions and the load carried by the transformer before overload, so as to give full play to the leverage of financial funds. Accident overload is only allowed to be used under accident conditions (transformers that can still operate)

the allowable value of accident overload shall comply with the regulations of the manufacturer; If there is no manufacturer's regulation, the self cooling oil immersed transformer can be operated according to the requirements in the following table

strengthen the daily maintenance of the transformer in operation

1. Strengthen the daily inspection of the transformer. Once any abnormality is found, repair it in time to ensure the normal operation of the transformer

2. Often observe the temperature display change of the thermostat, and observe whether the three-phase temperature calibration time is balanced. If the temperature display of a certain phase is abnormal, and the temperature rise of the transformer is abnormal, find out the cause in time

3. Strengthen the regular inspection of the transformer, and the inspection items include:

① check whether all fastening connections are loose

② check whether the connecting piece of the tapping gear is loose

③ check whether the fan, temperature controller device and other auxiliary devices can operate normally

④ check whether the shell and iron core are well grounded at one point

⑤ clean the dust and dirt on the transformer

⑥ replace the aged rubber pad in time to prevent the noise caused by the aging of the rubber pad

advantages and disadvantages of dry-type and oil immersed transformers

in terms of cost, dry-type transformers are more expensive than oil immersed transformers. The capacity of oil immersed transformer is larger than that of dry-type transformer. Dry type transformers are required in underground floors, floors and crowded places. Oil immersed transformers are used in independent substations. Box type substation generally uses dry-type transformer. When the space is large, the oil immersed transformer is used, and when the space is crowded, the oil immersed transformer is used. When the regional climate is humid, use oil immersed transformer. Dry type transformers are used in places that need "fire and explosion prevention". The capacity of dry-type transformer to bear load is worse than that of oil immersed transformer. Dry type transformers shall operate at rated capacity. The oil immersed transformer allows short-term overload