II. 250 MVA-132KV Power Transformer Type
1. Cooling Method:
For 250 MVA-132kV power transformers, the following cooling methods are applicable, with ONAF and OFAF/ODAF being the most prevalent.
-ONAN (Oil Natural Air Natural): The most basic cooling method, relying entirely on natural convection of oil and air. It is typically used for smaller ratings or as the initial cooling stage for a 250 MVA transformer. For this capacity, it is insufficient as a standalone cooling method at full load.
-ONAF (Oil Natural Air Forced): A standard and highly common configuration for 250 MVA transformers. It enhances the ONAN method by adding fans to the radiators. The fans are automatically staged based on oil temperature and load, providing a significant boost in cooling capacity without the need for oil pumps.
-OFAF (Oil Forced Air Forced): Employs oil pumps to force oil circulation and fans for forced air cooling. This method offers high efficiency and is a typical, robust configuration for 250 MVA units, especially where compact radiator size is desired.
-ODAF (Oil Directed Air Forced): An advanced form of OFAF, where forced oil flow is directed through specific winding channels for optimal heat transfer. This is a highly efficient and compact design, well-suited for large power transformers like 250 MVA, offering excellent thermal performance.
-OFWF (Oil Forced Water Forced): Uses oil pumps and a heat exchanger with forced water circulation. This method is employed when air cooling is insufficient or impractical, typically at sites with a readily available and reliable water source.
-ODWF (Oil Directed Water Forced): The most efficient method, combining directed oil flow with water cooling. It is used for the largest ratings or in specialized applications where maximum heat dissipation in a minimal footprint is critical.
2. Number of Windings:
-Two-winding transformer: This is the most common type, featuring only one high-voltage winding (132kV) and one low-voltage winding (typically 11kv,33kv etc.). It is used for a single voltage transformation.
-Three-winding transformer: This type has one high-voltage winding (132kV) and two medium-voltage/low-voltage windings. It is used in hub substations that need to supply power to two grids of different voltage levels simultaneously.
3.Voltage Regulation Method:
-Off-circuit tap changing: Requires de-energizing the transformer to manually adjust the tap changer. It has a small voltage regulation range (typically ±2×2.5% or ±5%). It is suitable for applications where voltage fluctuations are minimal and frequent voltage adjustment is not required.
-On-load tap changing (OLTC): (This is the absolute mainstream configuration for 132kV class transformers today.) It allows for automatic or manual adjustment of the tap position while the transformer is energized and under load, maintaining a stable output voltage. This is crucial for grid interconnection and ensuring power supply quality. The regulation range is typically ±8×1.25% or similar.
III. 250 MVA-132KV Transformer Standard & Certification
1. Standards: GB/T, IEC, IEEE C57, GOST, EN, AS (Customizable according to customer requirements)
2. Certification: ISO, CE, IECEE CB Scheme, SABS, EAC (CU TR), KEMA (Type tests available)
3. Efficiency: The no-load and load losses are optimized to achieve an operational efficiency greater than 99.7%, capable of meeting and exceeding European Ecodesign Tier 2 (2014/548/EU) and other international high-efficiency standards.
4. Maintenance & Design: High-degree sealed construction (IP65 on terminal boxes and control cabinets), corrosion-protected, designed for a service life of over 30 years with minimal maintenance.
5. Environmental Option: Environmentally friendly FR3® natural ester (vegetable) oil can be selected as the insulating liquid for enhanced fire safety and biodegradability.
6. Overload Capacity: Designed with high-purity copper windings, the transformer allows for short-term emergency overload up to 130% of rated capacity, subject to specific conditions and continuous monitoring of oil temperature (≤ 95°C).
IV. 250 MVA-132KV Power Transformer Price
The cost of a 25MVA transformer is project-specific. As a leading manufacturer, HENGFENGYOU ELECTRIC provides high-value, competitive pricing without compromising on quality and reliability.
To get an accurate price for your 25MVA-132KV power transformer, please provide us with your technical requirements or request a quote. Our engineering and sales team will respond within 24 hours with a comprehensive offer.
V. 250 MVA-132KV Transformer Case
Our goal is to become a world-leading manufacturer of electrical equipment. The business, experience, and technology accumulated over the years have earned the trust of customers in more than 50 countries worldwide. Once our customers establish a cooperative relationship with us, they become long-term partners, because Hengfengyou always insists on providing you with our best electrical products and services.
VI.250 MVA-132KV Power Transformers FAQ
Q1: What is a 250mva-32KV power transformer?
A 250mva-132kv power transformer is a high-voltage electrical device used to step up or step down voltage in power transmission and distribution systems, typically connecting substations between 132kV (primary side) and lower voltages (e.g., 11kV，33kV).
Q2: What are the common types of 250mva-132kv power transformers?
By Cooling Method: Oil-immersed (ONAN, ONAF, OFAF, OFWF, ODAF, ODWF), (rare for 132kV).
By Function: Step-down (132kV→lower voltage), step-up (e.g., generator output to grid).
By Phase: Three-phase or single-phase (usually grouped for three-phase systems).
Q3: What are key parameters of a 250mva-132kv power transformer?
Voltage ratio: 132kV/(11.5kV, 33kV, etc.).
Cooling class: ONAF (oil-natural air-forced), OFAF (oil-forced air-forced)，ONAN, OFWF, ODAF, ODWF
Vector group: YNd11,YnYn0D11, etc.
Q4: What standards apply to 250MVA-132kV power transformers?
This involves a multi-level standard system, with the core including:
Efficiency Standards: China's GB 20052-2024 (a mandatory national standard implemented in February 2025) , which sets mandatory requirements for no-load and load losses.
Basic Performance & Safety Standards:
IEC 60076 Series: The international common benchmark.
GB/T 1094 Series: Chinese national standards, equivalent to IEC 60076.
IEEE C57.12.00: The common standard for the North American market.
Specific Product Standards: Such as GB/T 23755-2020 for "Three-phase site-combined power transformers".
The applicable standards must be determined based on the target market. For instance, GB standards are mandatory in China, while export projects need to comply with IEC or the destination country's standards (e.g., IEEE, EN, GOST).
Q5. What is the typical delivery lead time for a 132kV power transformer?
Question 5: What is the typical delivery time for a 132kV power transformer?
Standard design: 35 days (includes design, material procurement, manufacturing, and routine testing).
Custom design: 50-90 days (for example, for special impedance, cooling methods, or certification requirements).
Expedited delivery: This can be negotiated to approximately 45 days, but typically incurs additional project management fees and air freight costs.
Q6. What is the designed service life of a 132kV power transformer?
The economic service life as per IEC/GB standards is typically 30 years. In practice, with proper load management (e.g., controlling winding hot-spot temperature ≤ 65°C), regular maintenance (like DGA), and timely overhaul, the transformer's actual service life can be extended to 40 years or longer.
Q7. What are the typical warranty terms for a 132kV power transformer?
Warranty Period: Typically 12 months from commissioning or 18 months from shipment (whichever comes first). The specific period is subject to the commercial contract and longer terms can be negotiated.
Warranty Coverage: Covers failures resulting from design and manufacturing workmanship defects (e.g., in windings, core, insulation). It excludes damages caused by improper operation, force majeure, or failure to adhere to maintenance guidelines.
Q8. What after-sales services are provided for 132kV power transformers?
Technical Support: Includes installation guidance, commissioning support, and on-site operator training.
Routine Maintenance: Offers services like oil testing, preventive testing, condition assessment, and major overhaul.
Emergency Response: Provides fault diagnosis and troubleshooting support, with optional emergency on-site service based on service agreements.
Upgrades & Retrofits: Offers technical services such as capacity increase, noise reduction, and intelligent retrofits (e.g., installing online monitoring systems).
