Auxiliary Transformer for Power Generation-110 / 220 kV

Attributes Description Documentation Resource Library

Key attributes

Brand	ROCKWILL
Model NO.	Auxiliary Transformer for Power Generation-110 / 220 kV
Rated frequency	50/60Hz
Series	S

Description

110kV-220kV auxiliary transformer (also known as station service or startup transformer) supplies reliable auxiliary power to power plant and substation systems. It steps down high voltage from the main grid or generator bus to medium voltage (6kV–10kV) for auxiliary equipment including pumps, fans, lighting, control systems, and communication devices.

Designed for continuous operation with redundant configurations, overload protection, and short-circuit safeguards. Compact oil-immersed or dry-type construction suitable for confined switchgear rooms. Optimized for partial-load efficiency with low no-load losses.

Features of Aux Transformer

Reliability-focused design — Continuous operation with backup unit configurations preventing downtime from primary transformer failures; essential for facilities where auxiliary power loss disrupts critical processes
Wide voltage adaptability — Primary side matches facility main power source; secondary outputs standard low and medium voltages aligned with auxiliary equipment requirements
Compact and space-efficient — Smaller footprint compared to main power transformers, suitable for confined switchgear rooms and auxiliary power rooms
Enhanced protection mechanisms — Built-in overcurrent protection, short-circuit protection, and temperature monitoring safeguarding both transformer and connected auxiliary loads
Durability in diverse environments — Oil-immersed variants resist moisture; dry-type (epoxy-cast) models ideal for indoor low-maintenance settings; designed for dust, vibration, and moderate temperature fluctuations
Efficiency for low-load operations — Optimized for partial and varying loads common in auxiliary systems, with low no-load losses ensuring energy efficiency at non-peak demand.

Technical Parameters

Parameter	Value (Typical Range)
Rated Power	5 – 50 MVA
High Voltage (HV)	110 / 220 kV
Low Voltage (LV)	6.3 / 10 / 10.5 kV
Rated Frequency	50 / 60 Hz
Number of Phases	3
Vector Group	YNd11 / Dyn1
Cooling Method	ONAN / ONAF
Short-circuit Impedance (10 MVA)	8% ≥ 8.0% min
Short-circuit Impedance (20 MVA)	10% ≥ 10.0% min
Short-circuit Impedance (40 MVA)	12% ≥ 11.0% min
Insulation Level (HV LI/AC, 110kV)	480 / 230 kV (Um=123kV)
Insulation Level (HV LI/AC, 220kV)	950 / 395 kV (Um=245kV)
Insulation Level (LV LI/AC, 12kV)	75 / 28 kV (Um=12kV)

Physical Picture of 220kV Auxiliary Transformer

110kV-220kV Auxiliary Transformer(Transformer for generation)

Environmental Conditions

Ambient temperature: −25 °C to +40 °C (24h average ≤ +35 °C)
Altitude: ≤ 1000 m
Relative humidity: ≤ 90% (at +25 °C)
Solar radiation: ≤ 1000 W/m²
Pollution level: Light to heavy

FAQ for transformer

Q: What are the core international and domestic standards governing power transformers up to 345kV, and what are their respective focuses?

Currently, mainstream standards are divided into three categories: international general standards, North American regional standards, and Chinese national standards. The core content and focus differences are as follows:

IEC 60076 series: The core international standard for power transformers, comprehensively covering key aspects such as design, testing, insulation requirements, and cooling systems. It serves as an important reference for national standard formulation in various countries.
IEEE C57 series (including ANSI C57): The dominant standard in North America, covering similar aspects of design, manufacturing, and testing as IEC 60076. It is tailored to the technical characteristics of North American power grids.
GB standards (e.g., GB20052-2013): Chinese national standards, most of which are harmonized with IEC standards. They propose specific requirements for efficiency and operational performance to ensure compatibility with China's power system.

Negotiable

Pricing calculator

Model

S-220/10

Warranty by

Whole life care manager

Whole-life care management services for equipment procurement, use, maintenance, and after-sales, ensuring safe operation of electrical equipment, continuous control, and worry-free electricity consumption.

The equipment supplier has passed platform qualification certification and technical evaluation, ensuring compliance, professionalism, and reliability from the source.