Oil Immersed transformer Transformer for Photovoltaic Power Generation

Transformer for Photovoltaic Power Generation

Rated voltage	0.4/6/10/20/35kv
Rated capacity	800kva-25mva
Application scenarios	High-Altitude & Extreme-Temperature PV， PV + Energy Storage (PV-ESS) Hybrid Systems， Distributed Commercial & Industrial (C&I) PV， Utility-Scale Ground-Mounted PV Plants
Certifications & Standards	TÜV -issued CE • CB IEC EN ISO 9001• 14001• 45001

Why Oil-Immersed Transformers Are Critical for PV Systems

Before diving into specs, it’s key to understand their PV-specific value:

Heat resistance for cyclic loads: PV power output fluctuates with sunlight, and oil-immersed designs (using mineral or ester oil) handle variable heat better than dry-type alternatives.

Outdoor durability: ZTELEC’s oil-immersed transformers resist dust, moisture, and extreme temperatures—critical for PV plants in deserts, coasts, or plateaus.

Efficiency alignment: Low no-load/load losses match PV’s goal of maximizing energy harvest, cutting operational costs long-term.

ZTELEC CHINA’s Oil-Immersed Transformers in Key PV Application Scenarios

ZTELEC’s transformers are not just spec-compliant—they’re optimized for the unique challenges of each PV environment. Below are real-world use cases:

Utility-Scale Ground-Mounted PV Plants (100+ MW)

These are the largest PV projects (e.g., China’s Gobi Desert PV bases, UAE’s Mohammed bin Rashid Al Maktoum Solar Park) and require high-capacity, weather-resistant transformers.

ZTELEC Solution: S13-M-20000/35 (20,000 kVA, 35kV MV side)

Why it works:

ONAF cooling handles 24/7 high loads from 50+ inverters.

Anti-corrosion tank coating resists sandstorms (tested to withstand 100 km/h wind-blown sand).

Case Study: ZTELEC supplied 60 units for a 1.2 GW PV plant in Xinjiang, China. The transformers operate at 98.8% efficiency, contributing to 2.1 TWh of annual clean energy—enough to power 500,000 households.

Distributed Commercial & Industrial (C&I) PV (1-50 MW)

C&I PV (e.g., factory rooftops, shopping mall parking lots) needs compact, low-noise transformers.

ZTELEC Solution: S11-M-1250/10 (1250 kVA, 10kV MV side)

Why it works:

Compact design (1.8m × 1.2m × 1.5m) fits rooftop/indoor spaces.

Noise ≤60 dB—compliant with urban industrial zone regulations.

Application Example: A 15 MW rooftop PV project at a Guangdong electronics factory uses 12 ZTELEC units. The system cuts the factory’s grid power costs by 40% and reduces carbon emissions by 8,000 tons/year.

PV + Energy Storage (PV-ESS) Hybrid Systems

PV-ESS systems (to solve solar intermittency) need transformers that handle bi-directional power flow (PV generation → grid, battery discharge → grid).

ZTELEC Solution: Custom S13-M-5000/20 (5,000 kVA, 20kV MV side) with OLTC (On-Load Tap Changer)

Why it works:

OLTC adjusts voltage dynamically during battery charging/discharging—no power loss.

Reinforced insulation resists voltage spikes from ESS inverters.

Global Project: ZTELEC supplied 15 units for a 75 MW PV + 30 MWh ESS project in Australia. The transformers ensure stable power dispatch during peak demand (3-9 PM), reducing grid reliance by 25%.

High-Altitude & Extreme-Temperature PV (≥2,000m Elevation)

PV plants in Tibet, qinghai (China) or the Andes (South America) face low air pressure and -30°C to 40°C temperature swings.

ZTELEC Solution: Custom S13-M-3150/10 with altitude adaptation

Why it works:

Thicker insulating paper (2mm vs. standard 1.5mm) compensates for low air dielectric strength.

Oil tank heaters prevent freezing in winter (auto-activates when temp ≤ -5°C).

Reliability Track: 20 ZTELEC units have operated in a 50 MW Tibet PV plant for 6 years—zero downtime, even in -25°C winters.

Common Key Specifications of ZTELEC CHINA’s Oil-Immersed PV Transformers (Table)

ZTELEC’s PV-focused oil-immersed transformers adhere to international standards (IEC 60076, GB/T 6451) and offer customization for project-specific needs. Below is a table of most-used specifications for mainstream PV applications

Parameter Category	Specification Details	ZTELEC Typical Models & Notes
Rated Capacity	Distributed PV: 500 kVA – 2.5 MVA Utility-scale PV: 3.15 MVA – 25 MVA	S11-M-1250/10 (1250 kVA): For 5-8 MW distributed projects S13-M-20000/35 (20,000 kVA): For 100+ MW ground plants
Voltage Class	LV Side (Inverter Match): 0.4 kV / 1.14 kV MV Side (Grid Connection): 10 kV / 20 kV / 35 kV	0.4kV LV: Matches 90% of PV inverters (e.g., 1500V DC inverters) 35kV MV: Standard for utility-scale grids in China/Europe
Insulation System	Insulation Class: Class A (≤60K temp rise) / Class B (≤70K temp rise) Insulating Oil: GB 2536 Mineral Oil (≤15ppm water) / Optional Ester Oil	ZTELEC uses Kraft insulating paper (high tear resistance) for PV’s cyclic loads Ester oil option for eco-sensitive areas (e.g., forests)
Temperature Limits	Top Oil Temp Rise: ≤55K (above ambient) Winding Temp Rise: ≤65K (Class A) / ≤75K (Class B)	Built-in PT100 sensors (ZTELEC patent) for real-time monitoring—vital for desert PV (ambient ≥45°C)
Efficiency Class	GB/T 6451 Class 1 (High Efficiency) No-Load Loss: 3.2 kW (2500 kVA model) Load Loss: 18.5 kW (2500 kVA model)	S13 series: 0.3-0.5% higher efficiency than Class 2 models—saves 5,000+ kWh/year per unit
Short-Circuit Withstand	10kV Side: 25 kA (2s) 35kV Side: 16 kA (2s) Winding Material: Copper/Aluminum	Reinforced copper windings (ZTELEC design) resist electromagnetic forces during PV inverter faults
Physical Features	Tank Material: Corrosion-resistant Q235 steel Noise Level: ≤65 dB (1m, 1250 kVA) Cooling Method: ONAN (Natural) / ONAF (Forced Air)	Anti-sand coating (optional) for desert PV ONAF cooling for 10+ MVA models (high-load scenarios)

Note: ZTELEC offers full customization for parameters like voltage, capacity, and cooling—tailored to regional grid standards (e.g., 20kV for EU, 35kV for China) and project conditions.