Transformers should be inspected and maintained regularly to ensure normal operation. You should check them annually in dry and clean environments, and every three to six months in areas that may be contaminated by dust or chemical fumes.
It is important to pay attention to many problems when maintaining and overhauling dry-type transformers, which require a certain amount of daily maintenance. For common dry-type transformers, what are the main standards for routine maintenance and testing? For your reference, here are the main inspection items:
1.The dry-type transformer should be checked for temperature:
The temperature of the oil in the upper layer of a dry-type transformer should be checked with a thermometer to determine if it is normal or close to or exceeding the high allowable level. It should be checked whether the instrument is inaccurate or the oil temperature is indeed abnormal when there is a significant difference between the glass thermometer and the pressure thermometer.
2.Check the oil level:
Check the oil temperature and oil color of the oil-filled high-voltage bushing, and determine whether there is oil leakage in the bushing. Also, examine the oil level and oil color of the dry-type transformer oil conservator. The cause of abnormal oil level indications must be determined. Sediment accumulation at the outlet and inlet of the oil level gauge may hinder oil passage, so it is important to keep an eye out for it.
3.Listen to the sound:
Is the electromagnetic sound of dry-type transformers abnormal compared to previous ones. There is usually no problem detecting abnormal noises in dry-type transformers because workers are used to the normal noise. Noise that is abnormal is usually caused by the following factors:
- The large fluctuations in the power frequency cause vibrations in the casing and radiator.
- There is a problem with the clamping of the iron core.
- Iron core short circuits occur due to defects in the iron core structure or in the iron core clamping screw and fastening bolt.
- It is loosely fastened.
- Lead or winding has discharged into the iron core or shell.
- Poor grounding or ungrounded metal parts cause electrostatic discharge.
4.On the top cover of a dry-type transformer, check the insulation:
Whether the outlet bushing and the supporting insulators leading out the conductive bar are clean, and whether there are cracks or discharge traces.
5.Ensure that the bolted joints leading out of the busbar are not overheated:
The infrared thermometer can be used to measure the apparent temperature change of the wax piece and the color-changing paint. Check the cable head for oil leaks when there is a cable terminal box.
6.Make sure there are no leaks of oil:
The dry-type transformer’s oil level will be reduced by oil leakage, and oil pollution will occur on the casing radiator, etc., contaminating its appearance. Check the gaskets of each valve and part carefully. Poor welding should be repaired immediately if it is the cause.
7.Make sure the valve is working：
Whether various valves should be opened and closed according to the work requirements. The valve can also loosen due to vibration, so inspections should be done to ensure it is operating properly.
8.Make sure the pipes are explosion-proof:
Make sure the explosion-proof pipe is not cracked, damaged, or showing fuel injection marks, and that the explosion-proof membrane is in good condition. Inspecting the explosion-proof pipe at a higher level requires special attention.
