33kV Fully Sealed Three-phase Low Loss Power Distribution Transformer

33kV three-phase oil-immersed transformers are widely used in rural power grids, industry, commerce, new energy, public facilities and other fields. They have been verified to have high reliability in more than 50 countries and regions around the world and have been sold to South Africa, Zimbabwe, Sudan, Kenya, Mozambique, Tanzania, Ethiopia, Nigeria, Namibia, Iraq, UAE, Saudi Arabia and other countries and regions.

 

33kv Oil immersed Transformer Technical Specifications

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- Input voltage: 33kV
- Output voltage: 0.4kV 0.415kv 0.420kv 0.44kv
- Capacity: 30-25000 kva
- Frequency: 50HZ/60HZ
- Voltage regulation mode: NLTC (no Load tap changer)
- Remark: voltage, capacity, frequency, connection group and loss can be customized according to customer requirements

Capacity	Rated voltage&Off-load tapping				Vector GroupSymbol		NO-load loss(W)	Load loss(W)	NO-load current	Short circuit impedance(%)
	H.V(kv)	High pressure Tap range(%)		L.V(kv)
50 kva	33kV 35kV 38.5kV	±5% ±2x2.5%		0.4 0.416 0.42 0.44	Dyn11 Yyn0		210	1270/1210	2.0	6.5
100 kva							290	2120/2020	1.8	6.5
150 kva							340	2500/2380	1.7	6.5
160 kva							360	2970/2380	1.6	6.5
200 kva							430	3500/3330	1.5	6.5
250 kva							510	4160/3960	1.4	6.5
300 kva							610	5010/4770	1.4	6.5
400 kva							730	5050/5760	1.3	6.5
500 kva							860	7280/6930	1.2	6.5
600 kva							1040	8280	1.1	6.5
750 kva							1230	9900	1.0	6.5
1000 kva							1440	12150	1.0	6.5
1250 kva							1760	14670	0.9	6.5
1500 kva							2120	17550	0.8	6.5
2000 kva							2490	20740	0.8	6.5
2500 kva							2950	24420	0.8	6.5
3000 kva							3510	29050	0.7	6.5
4000 kva							4200	34940	0.7	6.5
5000 kva							4960	41160	0.7	6.5

 

Type: 33kV three-phase transformer

These types of transformers have the same principle, but different structures, and different types of transformers have different applications.

33kV three-phase oil-immersed transformer (rated voltage 6kV-35kV)

33kV pole-mounted three-phase oil-immersed transformer (rated voltage 2.4kv-34.5kv)

 

33kv Oil immersed Transformer Case show

10KV 400KVA Three Phase Low Loss Distribution Transformer

The 10kV 400kVA Three-Phase Low Loss Distribution Transformer is a high-efficiency power solution designed for demanding urban and industrial applications. Utilizing advanced oil-immersed technology, it minimizes no-load and load losses, enhancing energy savings while ensuring superior thermal stability. Its core is crafted from high-quality cold-rolled silicon steel, reducing magnetic losses and boosting overall efficiency. The transformer features a fully sealed oil tank that prevents insulation degradation, extending its operational lifespan. With precise voltage regulation and low noise operation, it is an ideal choice for urban substations, commercial centers, and specialized industrial networks, delivering consistent and reliable power performance.

 

33kv Oil immersed Transformer FAQ

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What is an 33kV three-phase oil immersed transformer?

A three-phase oil immersed transformer is a power transformer that is cooled and insulated by insulating oil. It is designed for use in three-phase AC power systems and can convert high voltage electrical energy into low voltage (such as 33kV/400V). It is widely used in industrial, commercial, and power grid distribution.

 

What is a 33KV transformer?

33KV power transformers are commonly used in power transmission substations to step-down high-voltage transmission to distribution levels. 11KV transformers are more often used in distribution substations and on utility poles to further step-down voltage for supplying end users.

 

What are the typical application scenarios ?

*Voltage conversion of urban distribution network (33kV → 400V);

*Power distribution in industrial plants such as mines and petrochemicals;

*Grid connection of renewable energy power plants (such as wind farms);

*Hospitals, data centers, and other places that require high reliability power supply.

 

What is the rated capacity range ?

The common capacity ranges from 25kVA to 10MVA, with the 100kVA to 2000kVA models of 33kV/400V being the most widely used, depending on the load requirements.

 

What is the difference in maintenance cycle between 33kV dry-type and oil immersed transformers?

Dry type: Dust removal inspection every 2-3 years; Oil immersed: Check the oil level, oil quality (pressure resistance value, acidity), sealing, and radiator cleaning once a year; Comprehensive oil sample testing every 3-5 years (such as medium loss and moisture content).

 

How to choose between three-phase oil immersed transformer and dry-type transformer?

-33kV oil immersed transformers are suitable for outdoor, high-capacity, and high load scenarios, with low cost but requiring regular maintenance;

-33kV dry-type transformer: used in indoor environments with high fire protection requirements (such as shopping malls and subways), maintenance free but expensive.

 

How to determine whether a transformer needs to change oil or filter oil?

-Oil quality testing: Regularly test the breakdown voltage (should be ≥ 30kV), water content (≤ 20ppm), and acid value of the oil;

-Cloudy oil color: The oil becomes darker or there is an increase in suspended matter;

-Decreased insulation performance: determined by withstand voltage test.

 

 

What are the reasons for the abnormal temperature rise during operation?

-Long term overload;

-Cooling system malfunction (fan/oil pump shutdown);

-Oil circuit blockage or insufficient oil volume;

-Internal short circuit or poor contact.

 

How to deal with oil leakage in oil immersed transformers?

-Slight oil leakage: tighten bolts or replace gaskets;

-Serious oil leakage: Stop immediately, drain the oil and repair or replace components;

 

What protective devices must be configured for Q9?

*High voltage side: circuit breaker or fuse (with overcurrent/short-circuit protection);

*Body protection: gas relay, pressure relief valve, oil temperature gauge;

*System protection: lightning arrester (anti lightning impulse)

*Monitoring device: oil level gauge, online oil chromatography analyzer (high-end configuration).

 

 

What are the key points to pay attention to when installing Q10?

-Stable foundation, horizontal installation, avoiding tilting;

-Reserve sufficient heat dissipation space (such as at least 1.5 meters away from the wall);

-Grounding resistance ≤ 4 Ω;

-Check the oil level, sealing, and cleanliness of the casing.