Hey there! I'm a supplier of 138kv/132kv power transformers. Over the years, I've seen my fair share of issues with these big pieces of equipment. In this blog, I'll talk about the common faults of a 132kv power transformer.
1. Insulation Problems
One of the most frequent issues we come across is insulation problems. The insulation in a 132kv power transformer is crucial as it prevents short - circuits and ensures the safe and efficient operation of the transformer.
Moisture Intrusion
Moisture can get into the insulation system in several ways. For example, if the seals on the transformer are not tight, rainwater or humidity can seep in. Once moisture gets into the insulation, it can reduce its dielectric strength. This means that the insulation is less able to withstand the high voltages present in the transformer. As a result, there's a higher risk of electrical breakdown, which can lead to short - circuits and potentially damage the entire transformer.
Aging of Insulation Materials
Insulation materials, like paper and oil, degrade over time. The high temperatures inside the transformer, along with electrical stress, can cause the insulation to break down chemically. As the insulation ages, it becomes brittle and more prone to cracking. These cracks can allow electrical arcing to occur, which is extremely dangerous. You can check out our Oil Immersed Transformer page to learn more about how we ensure proper insulation in our products.
2. Overheating
Overheating is another common fault in 132kv power transformers. There are a few reasons why a transformer might overheat.
Overloading
If the transformer is asked to carry more load than it's designed for, it will generate more heat. For instance, during peak demand periods, if there's a sudden surge in the electrical load connected to the transformer, it can cause the temperature to rise rapidly. Over time, continuous overloading can damage the insulation and other components of the transformer. This can lead to premature failure of the transformer.
Poor Cooling
Transformers rely on cooling systems, such as oil - cooled radiators or fans, to dissipate heat. If these cooling systems are not working properly, the heat will build up inside the transformer. A clogged radiator or a malfunctioning fan can prevent the efficient transfer of heat away from the transformer. This can cause the temperature to soar, and if not addressed quickly, it can lead to serious damage.
3. Winding Faults
The windings in a 132kv power transformer are essential for transforming the voltage. However, they can develop faults.
Short - Circuits in Windings
A short - circuit in the windings can occur due to insulation breakdown. When two adjacent turns of a winding come into contact with each other because of damaged insulation, it creates a short - circuit. This can cause a large amount of current to flow through the short - circuited section, generating excessive heat and potentially melting the windings.
Open - Circuits in Windings
An open - circuit in the windings means that there's a break in the electrical path. This can be caused by mechanical damage, such as vibration or a physical impact on the transformer. When there's an open - circuit, the transformer will not be able to function properly, and it may cause an imbalance in the electrical system.
4. Tap Changer Problems
Tap changers are used to adjust the voltage ratio of the transformer. But they can also have their own set of issues.
Mechanical Wear
The tap changer has moving parts, and with repeated use, these parts can wear out. For example, the contacts in the tap changer can become worn or pitted over time. This can lead to poor electrical contact, which can cause arcing and overheating in the tap changer.
Incorrect Tap Setting
Sometimes, the tap changer may be set incorrectly. This can happen during installation or maintenance. If the tap setting is wrong, it can result in the transformer outputting the wrong voltage. This can cause problems for the electrical equipment connected to the transformer.
5. Oil - Related Issues
Most 132kv power transformers use oil for insulation and cooling. But there can be problems with the oil.
Contamination
The oil can get contaminated with dirt, moisture, or other impurities. Contaminated oil has reduced insulating properties and can also cause blockages in the cooling system. For example, if there's a lot of dirt in the oil, it can clog the radiator fins, reducing the cooling efficiency.
Oxidation
Oil can oxidize over time, especially when exposed to high temperatures and oxygen. Oxidized oil forms sludge, which can settle on the internal components of the transformer. This sludge can interfere with the proper operation of the transformer and can also cause overheating.
6. Core Faults
The core of the transformer is responsible for transferring the magnetic flux. Faults in the core can affect the performance of the transformer.
Laminations Short - Circuited
The core is made up of laminated sheets. If these laminations become short - circuited, it can cause eddy currents to flow in the core. Eddy currents generate heat, and excessive heat can damage the core and other components of the transformer.
Core Grounding Issues
Proper grounding of the core is essential. If the core is not grounded correctly, it can lead to electrical potential differences within the core, which can cause arcing and damage to the core.
7. Gas Accumulation
In oil - filled transformers, gas can accumulate due to various reasons.
Partial Discharges
Partial discharges inside the transformer can break down the oil and generate gases. These gases can accumulate in the gas - collection chamber of the transformer. If the gas levels get too high, it can indicate a serious problem, such as insulation breakdown.
Overheating of Oil
As mentioned earlier, overheating of the oil can also cause gas to be released. The decomposition of the oil at high temperatures produces gases like methane, ethane, and hydrogen. Monitoring the gas levels in the transformer can help detect potential problems early.
We offer a range of high - quality transformers, like our 125MVA 138KV 24.94KV Step Down Transformer and 25MVA 25000KVA 150KV Step Down Power Transformer With MR OLTC. If you're in the market for a reliable 132kv power transformer or have any questions about the common faults we've discussed, feel free to reach out to us for a purchase negotiation. We're here to help you find the best solution for your power needs.
References
- Electrical Power Systems Engineering textbooks
- Industry reports on power transformer failures