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33 KV - 500 KVA Low Noise Power Transformer Low Loss ONAN / ONAF Cooling

Categories Oil Immersed Transformer
Brand Name: Pearl Electric
Model Number: PEO-S, S9~13
Certification: KEMA, CE, CCC, ISO9001
Place of Origin: China
MOQ: 1 unit
Price: USD/RMB
Payment Terms: T/T, L/C
Supply Ability: 8000 units per year
Delivery Time: 35~50days ex-work
Packaging Details: Seaworthy wooden packing
Capacity: 33 kVA~10MvA or Customized
Rated H. V.: 33kv or Customized
Rated L. V.: 0.4kv or Customized
Vector Group: Dyn11 or Customized
Impedence: 4%-6% or Customized
Cooling: ONAN/ONAF or Customized
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33 KV - 500 KVA Low Noise Power Transformer Low Loss ONAN / ONAF Cooling

33 kV Oil - Immersed Transformer, Three Phases, Two Winding, Power Distribution


Oil-immersed type transformer features low noise, low loss, rational structure, high quality material, scientific design, strict production technology and advanced test method. The product also has the following additional advantages:

1. High mechanic strength, great anti-short circuit capability, excellent anti-lightning impulse capability and high reliability. All these performance indexes rank first in the industry in China.

2. Excellent overload capability, capable of continuously working under 110% rated load.

3. Low loss, energy-saving, economic and maintenance free.

4. Nice appearance, small size, less installation space occupation and low engineering cost.

5. Each performance index and technical specification excels that specified in China GB, international IEC and industrial standards.

6. Hermetically sealed corrugated tank structure is adopted, thus to effectively prevent air corrosion to the oil and prolong service lifetime of the transformer.


The core is manufactured with high quality cold rolled grain-oriented silicon steel of high magnetic conductivity, and 45° Mitring and steps overlapping structure is used for core production, thus to effectively reduce no-load loss and no-load current.

HV winding:

HV winding is manufactured with high quality copper conductor, adopting optimized structure to improve electric distribution. Lightning impulse wave process is carried out for calculation and analysis, thus to improve transformer's anti-lightning impulse capability.


LV winding is manufactured with high quality foil conductor, so the ampere-turn balance is excellent and the transverse magnetic flux leakage is low. The anti-short circuit capability is thus greatly improved. Oil conduit is rationally designed in the windings to increase winding's heat dispersion surface, effectively reduce temperature and improve transformer's overload capability.

Insulation Structure:

The transformer adopts class-A insulation. The HV and LV windings are arranged in concentric way. Between the windings are oil-clapboard insulation structure built with paper cylinder and small oil conduit.


The tank is jointed with high-quality steel. Rust-removing and phosphorization processes are carried out for the tank surface, then the surface is coated with FVC anti- erosion paint, thus to effectively prevent grease pollution and chemical erosion. The appearance is nice and harmonic with the environment. The whole structure is easy for installation and maintenance. It can be widely applied in outdoor environment and under harsh conditions.

Acoustic noise

The transformer, tap changing equipment and supplementary cooling equipment shall comply with the values stated in Table 1 — Audible sound levels for oil-immersed power transformers and be verified in accordance with IEC 60076-10.

The transformer shall be designed to meet the dBA noise level specified in schedule A of an enquiry document.

Table 1 — Audible sound levels for oil-immersed power transformers

Equivalent two-winding transformer rating (MVA)

Average Sound Level, (dBA)

Primary voltage 66kV

and below

Primary voltage greater than 66kV







For ONAF ratings, the sound levels are with the auxiliary cooling equipment in operation .

No.ItemsUnitItem 1
I Basic Information     
1.01Type Designation PEO-S-500/33/0.433
1.02Applicable Standards IEC 60076
1.03Manufacturer Pearl Electric
1.04Country of Origin China
II Pearl Electric Performance     
2.01Rated PowerkVA500
2.02HV 33
2.03LV 0.433
2.05Number of phase Three
2.06Insullation Class Class A
2.07Cooling Method ONAN
2.08Tapping Ranging ±2*2.5%
2.09Vector Group Dyn11
2.10Noise leveldB50
2.12No-load lossW870
2.13Load Loss (@75℃)W6960
2.14Max. Ambient Temperature40℃
Top oil temperature riseK60
Winding temperature riseK65
2.15Impulse Withstand Voltage(HV/LV)
2.16Power Frequency Withstand Voltage(HV/LV)
2.17Rated Duration of Short Circuits2
III Materials & Accessories     
3.01Core Materials Silicon Steel Sheet
3.02Winding Materials Copper conductor/foil
3.03Main Insulation Materials Mineral Oil
3.04Tap-changer Off-load tap-changer
3.05Pressure relief valve Yes
3.06HV&LV Cable Box & Extension Busbar Yes
3.07Bushing Yes, Porcelain Bushing
3.08Oil temperature thermometer Yes
3.09Oil Conservator N/A, Hermetiacally-sealed tank
3.10Terminal box Yes
3.11Oil-level indicator Yes
3.12De-hydrating breather N/A
3.13Cooling Radiator Corrugated Fin
3.14Current Transformer N/A
3.15Lightning Arrester N/A
3.16Transformer wheelpcsN/A
4.01Dimensions (L*W*H)mm1840X2550X2080
4.02Total masskg2400
4.03Colour PAL7035

Quality 33 KV - 500 KVA Low Noise Power Transformer Low Loss ONAN / ONAF Cooling for sale
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