How to operate and maintain the distribution transformer

1. Overload operation of distribution transformer

Transformer overload operation means that the load current exceeds the rated current of the transformer. In general, the transformer in the small load operation, its insulation materials cannot play a full role, and in the continuous overload operation, the transformer will produce high temperature, so that the winding insulation part is burned hard off, the formation of inter-turn short circuit; at the same time, the transformer oil sludge, accumulation in the oil tank plate, winding and core, resulting in poor heat dissipation of transformer oil. This vicious circle, not only seriously affects the life of the transformer, but will also cause high voltage breakdown and transformer burn and other accidents. Therefore, often observe the three-phase load current. Three phase load current strives to be consistent, such as deviation, should not exceed 10%. 

2. abnormal sound of distribution transformer

AC power through the transformer winding, due to self-vibration of the core will produce a normal uniform "humming" sound. If there is an abnormal sound, you need to find the cause and report to the relevant departments in time. The sound is also different when the transformer is unloaded and when it is loaded. According to the abnormal sound characteristics and previous comparison, find out the reason before putting it into operation.

3. Distribution transformer temperature inspection

The operating temperature of the transformer has a great relationship with its life. Transformer in the normal temperature of 95 ℃ below the operation, its life for 20 a; if the operation to 110 ℃, life will be shortened to 7 a; if the temperature rises to 130 ℃ operation, its life will be shortened to 2 a; transformer in 170 ℃ temperature continuous operation, d about will be scrapped. 10 temperature exceeds the allowable value of the transformer, to identify the causes and take countermeasures in a timely manner. 4.

4. distribution transformer oil level is normal, there is no seepage, oil leakage or oil color abnormal phenomenon

There are many reasons for the oil level to drop. Due to the welding quality and poor sealing, so that the heat sink tube, valve, box edge and other places are easy to seepage, leakage of oil. When the oil level drops below the transformer cover, the contact surface of oil and air increases, it is easy to oxidize and degrade and absorb the moisture in the air, resulting in the reduction of the oil's voltage strength, thus destroying the insulation performance of the winding. When the lack of oil is serious, the conductive parts of the transformer to the ground and each other's insulation is reduced, resulting in inter-phase or ground breakdown discharge. At this time, if you continue to use, the transformer oil cannot be normal circulation convection, resulting in transformer oil temperature rise, shortening the life of even burned.

5. distribution transformer insulation bushing has no damage, rupture and discharge traces

Insulation bushings are not cleaned for a long time, or have broken cracks and discharge traces, in the rainy or foggy weather, insulation bushings leakage current due to air humidity and increase, insulation drop, will occur to ground flashover. In addition, the insulation sleeve accumulation of serious scale, as well as insulation sleeve with large fragments and cracks, will also cause flashover or explosion accidents. To solve this phenomenon in addition to observe the insulation bushing itself, but also pay attention to the casing of the accumulation of dirt law, such as wind direction, the surrounding environment, so as to do a good job of cleaning.

6. Periodic cleaning of distribution transformer

To regularly clean the dirt on the distribution transformer, check whether the casing has flashover discharge, whether the grounding is good, whether there are broken wires, desoldering, fracture phenomenon, to regularly shake the grounding resistance, its resistance value is not more than 4 Ω (capacity 100 kV-A and above) or 10 Ω (capacity less than 100 kV-A), or take anti-fouling measures, install the casing anti-fouling cap. When connecting or disconnecting distribution transformer lead wires, strictly follow the process to avoid internal fracture of the lead wires.