II. Available 25 kVA Transformer Types
HENGFENGYOU ELECTRIC designs and manufactures a comprehensive range of 25 kVA transformers utilizing the same fundamental electromagnetic principles but engineered with distinct structural topologies to satisfy diverse global grid applications.
-
25 kVA Three-Phase Oil-Immerse Transformer (Rated Voltage: 6 kV to 35 kV) – Ideal for rural electrification networks and low-density power distribution.
-
25 kVA Cast Resin Dry-Type Transformer (Rated Voltage: 6 kV to 35 kV) – Perfect for indoor applications with limited space and strict fire-safety requirements.
-
25 kVA Single-Phase Pole-Mounted Transformer (Rated Voltage: 2.4 kV to 34.5 kV) – Highly cost-effective for overhead utility grids and remote rural single-household power supply.
-
25 kVA Single-Phase Pad-Mounted Transformer (Rated Voltage: 2.4 kV to 34.5 kV) – Tailored for North American underground low-profile residential systems.
-
25 kVA Three-Phase Pad-Mounted Transformer (Rated Voltage: 2.4 kV to 34.5 kV) – Engineered for reliable compact commercial and underground power infrastructure.
-
25 kVA Isolation Transformer (Low Voltage: 120V, 127V, 208V, 220V, 380V, 400V, 600V) – Engineered for precise voltage matching, grid filtering, and galvanic signal isolation.
III. Core Engineering Advantages of HENGFENGYOU 25 kVA Transformers
-
Global Standard Compliance: Fully complies with GB, IEC, GOST, EN, NF, and ANSI/IEEE standards. Custom engineering is available to meet specific utility grid codes.
-
International Certifications: Certified by ISO9001, CE, IEC, SABS, COC, CSA, and UL, assuring global cross-border market entry and insurance approval.
-
Premium Eco-Design Efficiency: System efficiency exceeds 99%, fully satisfying the stringent European 2015/2014/548/EC Ecodesign Tier 2 energy efficiency regulations, lowering long-term operational costs (OPEX).
-
Maintenance-Free Enclosure: Featuring an IP65 hermetically sealed protection level. It is 100% dustproof and moisture-proof, offering a maintenance-free design with an engineered operational lifespan of over 25 years.
-
Eco-Friendly Sustainability: Optional biodegradable FR3 vegetable/ester oil is available to reduce carbon footprint and mitigate environmental hazards.
-
Robust Overload Capacity: The high-purity copper-wound 25 kVA model reliably supports a short-term emergency overload up to 150% of the rated capacity for up to 2 hours (requires top oil temperature monitoring to remain ≤ 95 ℃).
IV. Price of 25 kVA Transformer
Are you looking for wholesale pricing or a commercial proposal for a specific project? Click the links below to receive a factory-direct wholesale quotation within 24 hours:
V. Global Project Showcases & Success Stories
Scale Your Energy Business with HENGFENGYOU ELECTRIC
As a premium global electrical equipment manufacturer, our accumulated engineering expertise and cutting-edge manufacturing technology have benefited EPC contractors and utilities in more than 50 countries. We focus on establishing long-term, trusted partnerships by delivering zero-defect power products and unparalleled technical support.

VI. Frequently Asked Questions (FAQ) for 25 KVA Transformers
What are the typical application scenarios of 25kVA three-phase oil immersed transformers?
*Power distribution for small and medium-sized factories;
*Electricity supply for commercial buildings, hospitals, or schools;
*Voltage conversion of rural power grids or community distribution systems;
*Power distribution at temporary construction sites.
What are the common configurations for its rated input/output voltage?
*High voltage side: 11kV (domestic distribution standard);
*Low voltage side: 400V (three-phase four wire system, line voltage 400V/phase voltage 230V);
How to calculate its rated current?
*High voltage side: I=25kva/11kV/√3=1.31A
*Low voltage side: I=25kva/0.4kV/√3=36.09A
What are the requirements for the surrounding environment during installation?
*Good ventilation, keep away from flammable and explosive materials;
*The basic platform needs to be level and load-bearing (with an oil content of about 200kg);
*Reserved heat dissipation space (with a side distance of ≥ 0.8 meters from the wall and no obstruction at the top);
*Outdoor installation requires the installation of rain covers or fences.
What is the overload capacity of a 25kVA transformer?
*Short term overload (such as within 2 hours) can reach 150% load (copper coil);
*Long term overload will accelerate insulation aging, and it is necessary to avoid operating beyond the rated capacity.
What are the key points to pay attention to in daily maintenance?
*Oil level check: The oil gauge of the oil pillow should be within the marked range;
*Oil temperature monitoring: During normal operation, the top oil temperature is ≤ 65 ° C;
*Leakage inspection: Check for oil leakage in the fuel tank welds and gaskets;
*Regular tests: insulation oil withstand voltage test, winding DC resistance measurement (once a year).
How to determine whether insulation oil needs to be replaced?
*Breakdown voltage: below 30kV (new oil standard ≥ 35kV);
*Excessive acid value:> 0.1mg KOH/g;
*High moisture content:> 20ppm;
*Oil color dark black or with carbide particles (needs to be filtered or oil changed).
*Reason: Overload, blocked radiator, oil circulation failure, internal winding short circuit;
*Solution: Immediately reduce the load and check the load; Clean the heat sink or repair the cooling system; Suspend maintenance for internal faults.
What protective devices must be configured?
*High voltage side: drop out fuse or circuit breaker (overcurrent protection);
*Low voltage side: air switch (short circuit protection);
*Body protection: gas relay, pressure relief valve, thermometer;
*System protection: lightning arrester (lightning protection), grounding device (grounding resistance ≤ 4 Ω).
10. How to choose energy efficiency level when purchasing?
*Standard: According to local national energy efficiency regulations or customer requirements
*Example: 25kVA oil immersed transformer with the latest energy efficiency in Europe has a no-load loss of 67W and a load loss of 630W; Energy efficiency>98.63%