What Is a 132/33kV 50 MVA Transformer?

A 132/33kV 50 MVA transformer on high-voltage power transformer used to step down voltage from 132kV (transmission) to 33kV (distribution level). With a capacity of 50 MVA (megavolt-amperes), this transformer is ideal for regional substations, industrial plants, and renewable integration hubs.


Technical Specification Table

ParametriTekniset tiedot
Rated Power50 MVA
Primary Voltage (HV)132 kV
Secondary Voltage (LV)33 kV
Vector GroupDyn11 / YNd1 / YNd11 (as per design)
Taajuus50 Hz / 60 Hz
Phase3-Phase
JäähdytystyyppiONAN / ONAF (Oil Natural / Forced)
Tap ChangerOLTC (±10%, ±16 steps) or NLTC optional
ImpedanceTypically 10.5% – 12%
Dielectric StrengthHV: 275kV / LV: 70kV impulse
Bushing TypePorcelain or Composite
EristysluokkaClass A / F
ProtectionBuchholz relay, PRV, OTI, WTI, DGPT2

Applications of 132/33kV 50 MVA Transformer

  • Grid Substations
  • Large Industrial Plants
  • Wind & Solar Farms
  • Urban Transmission Hubs
  • Oil & Gas Installations
  • Interconnection with Power Utilities

Cooling Methods Explained

  • ONAN – Oil Natural Air Natural (standard for up to 50 MVA)
  • ONAF – Oil Natural Air Forced for improved performance under peak loads

Construction & Design

  • Core: Cold-rolled grain-oriented silicon steel
  • Winding: Copper (high-conductivity), layered or disc winding
  • Tank: Hermetically sealed or conservator type
  • Cooling Radiators: Detachable for modular maintenance
  • Accessories: Oil level gauge, breather, pressure relief device, temperature indicators, etc.

Standard Compliance

  • IEC 60076
  • ANSI/IEEE C57
  • IS 2026 (India)
  • GB/T 6451 (China)
  • BS EN Standards (UK)

Why Choose a 50 MVA Transformer at 132/33kV?

  • Balances high capacity with manageable size
  • Ideal for step-down to regional grids
  • Ensures high-efficiency transmission with minimal losses
  • Compatible with smart grid SCADA integration

132/33kV 50 MVA Power Transformer

Frequently Asked Questions (FAQs)

Q1: Can this transformer support dual voltage outputs?
Yes. With dual secondary windings or tap changer settings, the transformer can support flexible output.

Q2: Is OLTC mandatory?
For systems requiring voltage regulation, OLTC is preferred. However, for fixed-load conditions, NLTC can be used.

Q3: How long does a 132/33kV transformer last?
With proper maintenance, the expected service life is 25–35 years or more.