ZMJ POWER
Oil Immersed Transformer
Oil-Immersed Transformer, also known as an oil-filled transformer, is a type of transformer where the core and windings are immersed in insulating oil. This type of transformer is commonly used for power distribution and transmission due to its efficient cooling and insulation properties.
Technical Parameters
| Phrase | Three-phase |
| Rated Capacity | UP TO 31500 KVA |
| Rated Voltage | UP TO 40.5 KV |
| Secondary Voltage | 0.4 KV |
| Frequency | 50Hz / 60Hz |
| Winding Material | Copper / Aluminum |
| Iron Core | Cold-rolled Silicon Steel Sheet |
| Insulation Material | Transformer Oil (25#/45#) |
| Standard | GB1094.1 (IEC60076) |
| Connection Symbol | Dyn11/Yyn0/YNd11 |
| Voltage Regulation | Unexcited |
| Cooling Type | ONAN / ONAF |
| Running Environment | Highest temperature: + 40 ℃ Lowest temperature: -45 ℃ Altitude: ≤ 4000 m Highest monthly average relative humidity: 90% (20 ℃) Installation location: without fire, explosion danger, serious foul, chemical corrosion, or violent vibration. |
Product Details
Questions and Answers
Oil-immersed transformers offer several advantages over dry-type transformers:
- High Efficiency: Oil serves as an excellent coolant, allowing oil-immersed transformers to handle higher loads and operate more efficiently than dry-type transformers of similar size.
- Better Heat Dissipation: Oil has a higher heat capacity compared to air, enabling oil-immersed transformers to dissipate heat more effectively, resulting in improved thermal performance and increased overload capacity.
- Longer Lifespan: The effective cooling provided by oil helps in extending the lifespan of the transformer by maintaining lower operating temperatures, reducing thermal stress on the insulation materials.
- Robustness and Reliability: Oil-immersed transformers have proven to be robust and reliable in various environments and under diverse operating conditions, providing consistent performance over a long service life.
- Suitability for High Power Applications: They are well-suited for high-power applications and larger capacity transformers, where the superior cooling capabilities of oil are beneficial.
- Compact Design: Oil-immersed transformers tend to have a more compact design compared to dry-type transformers of the same power rating, making them more space-efficient in certain installations.
- Improved Insulation: Oil provides better insulation properties than air, enhancing the transformer’s dielectric strength and reducing the risk of electrical breakdown.
- Self-Healing Properties: Transformer oil has self-healing properties that can prevent minor faults or arcing from causing catastrophic failures, improving overall reliability.
- Less Susceptible to Environmental Factors: Oil-immersed transformers are less affected by environmental factors such as dust, moisture, or pollution compared to dry-type transformers, making them more suitable for outdoor installations.
- Customizable Design: Oil-immersed transformers can be designed with various cooling systems such as radiators, oil pumps, and fans to enhance their cooling efficiency, making them adaptable to specific operating conditions.
While oil-immersed transformers have these advantages, they may not be suitable for all applications, especially those where fire safety, environmental concerns, or specific regulatory compliance favor dry-type transformers. The choice between the two types depends on various factors including application requirements, safety considerations, and environmental constraints.
Selecting oil-immersed transformers over other types, such as dry-type transformers, depends on specific circumstances and considerations:
- High-Power Applications: Oil-immersed transformers are well-suited for high-power applications and larger capacity transformers, where their superior cooling capabilities and efficiency make them advantageous.
- Longevity and Reliability: In situations where longevity and proven reliability are critical, oil-immersed transformers often outperform other types due to their robust design and efficient cooling, leading to a longer service life.
- Environmental Conditions: If the installation site is exposed to harsh environmental conditions, such as high humidity, extreme temperatures, or pollution, oil-immersed transformers are more resilient and less susceptible to environmental factors.
- Outdoor Installations: For outdoor installations where exposure to weather elements is a concern, oil-immersed transformers with appropriate weatherproof enclosures and insulating oil offer better protection compared to dry-type transformers.
- Space Limitations: In some cases, oil-immersed transformers can be more compact for a given power rating compared to other types, making them a suitable choice when space constraints are a concern.
- Regulatory Compliance: In certain industries or regions where specific standards or regulations favor the use of oil-immersed transformers due to their performance characteristics and historical reliability.
- Cost Efficiency for Large Installations: In larger installations where the efficiency gains and longer lifespan of oil-immersed transformers outweigh the initial higher cost compared to dry-type transformers.
- High Overload Capacity: Oil-immersed transformers generally have better overload capacity due to their superior cooling capabilities, making them suitable for applications where intermittent high loads are expected.
- Continuous Operation: In applications where the transformer needs to operate continuously at or near its full capacity, oil-immersed transformers can handle such conditions more effectively.
However, it’s crucial to balance these advantages with factors such as safety considerations, environmental impact, and specific application requirements. In scenarios where fire safety, environmental concerns, or regulations favor alternatives, such as dry-type transformers, those might be more suitable despite the advantages of oil-immersed transformers.
Routine Test
Measurement of winding resistance
Measurement of voltage ratio and check of phase displacement
Measurement of short-circuit impedance and loss
Measurement of no-load loss and current
Dielectric routine tests
Tests on on-load tap-changers, where appropriate
Leak testing with pressure for liquid-immersed transformers(tightness test)
Tightness tests and pressure tests for tanks for gas-filled transformers
Check of the ratio and polarity of built-in current transformers
Check of core and frame insulation for liquid immersed transformers with core or frame insulation
Type Test
Temperature-rise type test
Dielectric type tests
Determination of sound level for each method of cooling for which a guaranteed sound level is specified
Measurement of the power taken by the fan and liquid pump motors
Measurement of no-load loss and current at 90% and 110% of rated voltage
Special Test
Dielectric special tests
Winding hot-spot temperature-rise measurement
Determination of capacitances windings-to-earth, and between windings
Measurement of dissipation factor(tanδ) of the insulation system capacitances
Determination of transient voltage transfer characteristics
Measurement of zero-sequence impedance(s) on three-phase transformers
Short-circuit withstand test
Measurement of d.c. insulation resistance each winding to earth and between windings
Vacuum deflection test on liquid immersed transformers
Pressure deflection test on liquid immersed transformers
Vacuum tightness test on site on liquid immersed transformers
Oil Immersed Transformer:
650KVA＜ Rated Capacity ≤ 10MVA: 8504220000
Rated Capacity ≤ 650KVA: 8504210000
Dry Type Transformer:
Rated Capacity ＞ 500KVA: 8504349000
16KVA < Rated Capacity ≤ 500KVA: 8504339000
For orders of less than 5 transformers, we can usually deliver within 1 month. If the customer is particularly anxious or has special requirements, we can also handle it flexibly. Before signing a sales contract each time, we will agree on a delivery time with the customer based on the actual situation.