Transformer Selection for Solar & Wind Renewable Projects

Complete guide to selecting transformers for solar PV and wind farms. Learn about kVA matching, voltage step-up, harmonics, dry vs oil, and FAQs.

Renewable energy projects such as solar PV and wind power have special requirements for transformers. Unlike traditional industrial loads, solar and wind systems involve bidirectional power flow, frequent voltage fluctuations, high harmonics, and special environmental conditions.

A standard distribution transformer may not be suitable. This guide explains how to select the right transformer for renewable energy projects, with recommendations for JGELEC’s S11, S13, S20 oil-immersed transformers and SC(B)H15 high-efficiency dry-type transformers.

Key Requirements for Solar & Wind Transformers

1. kVA Rating Matching

Transformer capacity should be 1.1–1.25 times the inverter capacity to account for:

• Reactive power
• Harmonic currents
• Short-term overload
• Efficiency losses

Example:

1MW solar inverter → select 1250kVA transformer

2. Voltage Step-Up Configuration

Common voltage ratios:

• 0.4kV / 10kV
• 0.4kV / 35kV

These step-up transformers connect low-voltage inverter output to the medium-voltage grid.

3. Harmonic and DC Bias Tolerance

Solar inverters generate harmonics that can cause transformer overheating. JGELEC renewable energy transformers are designed to resist harmonics and reduce vibration and noise.

4. Environmental Durability

Most solar and wind farms are located outdoors, often in remote areas.

• Oil-immersed transformers are preferred for outdoor durability
• Dry-type transformers are used for indoor grid-connection stations

5. Voltage Regulation and Taps

Tap range: ±2×2.5%

Ensures stable output under fluctuating renewable energy generation.

Recommended JGELEC Models

For Large Solar & Wind Farms

• S11-M, S13-M, S20 oil-immersed transformers
• Strong outdoor durability
• High efficiency
• Low maintenance

For High-Efficiency Stations & Urban Renewable Projects

• SC(B)H15 amorphous alloy dry-type transformers
• Ultra-low no-load loss
• Fire-resistant and eco-friendly

FAQ

Q1: Can I use a standard industrial transformer for solar projects?

A: It is not recommended. Renewable energy transformers need better harmonic resistance and overload capability.

Q2: What size transformer do I need for a 1MW solar system?

A: A 1250kVA transformer is the most suitable choice.

Q3: Which cooling method is best for outdoor solar farms?

A: Oil-immersed natural cooling (ONAN) is stable and reliable.

Q4: Can JGELEC transformers work in parallel?

A: Yes, as long as vector group, voltage ratio, and impedance are consistent.

Q5: Are amorphous alloy transformers good for solar applications?

A: Yes, they reduce no-load loss significantly, especially when power generation fluctuates.

Q6: Does JGELEC provide transformers for 35kV renewable projects?

A: Yes, we supply 35kV oil-immersed and dry-type transformers for large-scale solar and wind farms.

Call to Action

JGELEC has rich experience in providing transformers for solar PV, wind power, and microgrid projects. Contact our technical team to get professional model selection, drawings, and competitive pricing for your renewable energy project.