Transformers play vital roles in electrical power systems because they enable the electricity conversion between circuits’ different voltage levels. Their efficiency, durability, and durability depend on being well-maintained as possible, which is why maintenance is so important. Like all other equipment, transformers may suffer from faults, which may result into power blackouts, equipment’s damage or even pose safety risks to individuals.
In this article control transformer manufacturers India will explain the list of activities need to be followed for transformers maintenance, including preventive measures and best practices.
1. Types of Transformer Maintenance
There are primarily three categories of transformer maintenance:
Routine Maintenance: Carried out frequently as part of the operation plan for the organization.
Preventive Maintenance: Preventive also include set time for maintenance and repairs that are done in advance to prevent further damages.
Predictive Maintenance: In its case of active monitoring, it has a means of using data from the monitoring systems to anticipate and likely avoid some fault.
It need to be understood that every type of maintenance entails different check points and measures, however, the check list helps you to make sure that no critical aspect is omitted.
A. Visual Inspection
Regular visual inspections are important because they establish the initial often-suspected issues that include oil leakage or the deterioration of a component.
Oil Level: Check how many litres of oil are still remaining in the conservator tank. By so doing, the oil’s ability to cool the engine is compromised and the insulation give in when oil levels are low.
Oil Leakage: The general indications of excess oil are around gaskets, bushings and radiators.
Physical Condition of Bushings: Check for cracks or chips on the porcelain steeled surfaces. Because the bushings connect the live conductors to the tank, their condition is critical.
Rust and Corrosion: Check what condition the tank and structure is in, whether they are rusty or have eroded in a way that may weaken the physical formation of the transformer.
Color of Silica Gel: You are required to check the color of the silica gel in the breather. It should be blue. The information on the need for the change is given if the color is pink or white, which means the blotting material has absorbed moisture.
External Temperature Gauge: Check that thermocouple readings correspond to a normal temperature range.
B. Electrical Testing
Various electrical tests aid in assessing the functionality and reliability of the electrical system.
Insulation Resistance Test: With insulation health in mind, make measurement of insulation resistance between the windings and the ground.
Turns Ratio Test: This affirms the right proportion of the primary and secondary winding so that the transformer is running effectively.
Power Factor Test: Applied to inspection of insulation conditions by measuring dielectric losses in the insulation.
Sweep Frequency Response Analysis (SFRA): Inspects for any signal of the physical changes or shift of the internal transformer members.
Dielectric Breakdown Voltage of Oil: This test examines capacity of the oil to withstand voltage applied to the product. In case of low breakdown voltage it may indicate contamination or moisture in the oil.
C. Oil Testing and Filtration
Transformer oil also fulfills the functions of insulation and coolant of the transformer. Periodic testing and purging keep this approach as optimally beneficial as possible.
Dissolved Gas Analysis (DGA): Identifies dissolved gases in the transformer oil that may reveal internal arcing, overheating, or internal insulation deterioration.
Moisture Content Test: It has been noted that moisture in the oil in particular leads to damage of insulations. It concerning the finished product, the moisture content should not exceed or be below the acceptable levels.
Furan Analysis: There are tests which check for furan compounds, which would show the degradation of paper insulation.
Acidity Test: Measures the oil’s acidity. Higher levels of pH affect corrosion and degrade the insulation.
Particle Count: This checks for solid contaminants in the oil.
Oil Filtration: When the oil deteriorates (obviously through moisture, impurities or dissolved gases) it is advised to filter the oil so as to regain its dielectric strength.
D. Mechanical Inspection
For safety in operation of the transformer, mechanical integrity is very important.
Tightening of Bolts: Step 3: Tighten all bolts and clamp connectors especially at the bushing and the tank covers.
Alignment of Components: Look for shift of any part in the radiators, conservator tanks, or external hook-ups.
Condition of Cooling Fans and Radiators: Check that all cooling fans and individual parts of the radiator are in good conditions.
Transformer Core Grounding: Inspect the grounding of the transformer core to prevent stray circulating currents.
E. Functional Testing
Functional tests aim at guaranteeing the efficiency and functionality of certain elements.
Cooling System Operation: Check the efficiency of the fan, oil pump, and the radiator. Verify the auto change-over of the cooling plant in the event of increase in temperature.
Alarm and Trip Circuit Test: Check the alarm and trip circuits working during types of faults such as high oil temperature or overcurrent.
Tap Changer Inspection and Testing: End-on has to check for signs of potential wear and tear while functional tests have to be performed to determine whether or not the tap changer can isolate taps under rated load.
F. Grounding System
The grounding system makes it safe by allowing the fault currents to be discharged to the earth.
Ground Resistance Testing: It is necessary to take the ground resistance reading frequently in order to know if it is within the specified range. When grounding is inadequate, there are risks associated with safety and the functioning of protective equipment.
Condition of Ground Connections: Examine all connecting GREYs to be concerned of corrosion or loosening.
G. Surge Arresters
LBs protect transformers from over voltages resulting from lightning strikes or switching operations.
Physical Inspection: Some functions that would be carried out in the building will be to check for areas of any damage, corrosion and contamination.
Insulation Resistance: Check the insulation resistance of the surge arresters to ascertain whether they are working or not.
Leakage Current Measurement: Check the leakage current since a high leakage is a sign that the insulation is breaking down from the inside.
3. Preventive Maintenance Schedule
On this basis, there should be a proper schedule in regard to maintenance, depending on age, climate conditions, and load operation of the transformer.
Daily:
- Check the state of silica gel in the breather convenience
- As often mentioned before, start with a proper visual inspection of the work area, the equipment and the tools.
- Take the following measurements: the cooling system’s readings, temperature gauges, and pressure gauges.
Quarterly:
- Test insulation resistance.
- External Surfaces should be washed and exterior part of bushings and radiators should be free from dust or any other material.
Annually:
- Make DGA and oil test.
- Also, conduct power factor testing, transformer turns ratio test and functional testing on protective relies.
- Check and vacuum cooling fans and radiators, if present on the vehicle.
Every 3-5 Years:
- Bulk oil test and filtrations.
- Regular tests done on the on-load tap changer with detailed inspection as well as the overhaul of the OLTC.
- It is possible to perform an internal inspection of transformer windings, if necessary.
4. Importance of Record Keeping
Even as important as the maintenance is, record-keeping on maintenance is equally important. Record keeping is useful for trend analysis, it provides the information needed for product history and for planned maintenance. Every test, inspection or replacement should be recorded sufficiently, and descriptions and results of inspection should be documented.
5. Common Issues and Troubleshooting
Even when transformers are properly maintained, transformers may face few problems. Some common problems include:
- Overheating: They include overloading, inadequate cooling, and low oil level.
- Oil Leaks: This may be gotten as a result of damaged gaskets or loose bolts.
- High Moisture Content: They may occur mainly because of breather failure or oil contamination.
- Internal Arcing: Supposed to be detected through DGA and means insulation failure.
It will also be useful in identifying potential problems with the transformer and resolve these problems early enough to avoid any major mishaps with the transformer thus slowing down the operational life of the transformer.
Conclusion
Thus, the problem of transformer maintenance is most urgent and plays an essential role in the proper functioning of electrical powersystems. Thus, by adhering to a detailed analysis of the modern guideline template, utilities and industrial operators can prevent serious failures, maintain safety and minimize expenditure. For transformers to stay in good working conditions for many years, preventive maintenance should be carried out alongside modern monitoring tools.
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