Transformers & Switchgear for Solar & Wind
Utility-scale solar and wind plants need transformers built for inverter-duty service: daily thermal cycling, bidirectional power flow, and 25+ year asset life under brutal outdoor exposure. Our renewables-duty equipment handles all three.
What Makes Renewables Different
- Inverter-duty service. Solar inverter step-up transformers (skid or pad-mount) take 600–800 V from the inverter up to 34.5 kV for collection. The load is unidirectional from LV side most of the time, but bidirectional during reactive support.
- Daily thermal cycling. Brutal — full output during the day, near-zero at night. Insulation systems must tolerate this for 25+ years.
- Aggressive loss evaluation. Developers capitalize losses at $4–8 per watt over project life, justifying premium core steel and larger conductors.
- Outdoor in harsh environments. Desert solar farms see -10°C nights and 50°C days. Wind turbine base transformers face salt spray (offshore), dust (onshore), and continuous vibration.
What We Build for Solar & Wind
- Inverter-duty pad-mounted transformers from 600 kVA to 5 MVA. Special winding configuration to handle inverter switching transients. Mineral-oil or natural ester filling per project preference.
- Wind turbine base transformers rated for the constant load profile typical of utility-scale wind. Dual-secondary configuration for 12-pulse / 18-pulse rectifier wind generators.
- MV collection switchgear (15–35 kV) — pad-mount style for outdoor installation at the project substation. SF6-free vacuum breaker preference.
- Project step-up transformers for the substation tying to the utility transmission system. These are usually large (10–50 MVA), built to utility specs (often Westinghouse / GE legacy designs).
Specification Considerations
Loss Evaluation Models
Most renewables developers capitalize no-load losses at $4–8/W and load losses at $0.50–1/W. We provide loss-cost analysis with every quote so you can compare on lifecycle cost, not just initial price.
Bidirectional Protection
Reactive power support means power can flow back through the transformer. Protection schemes have to handle bidirectional fault contributions and the unusual fault behavior of inverter-fed systems (typically 1.1× rated current, not the 8–10× from rotating machinery).
Anti-Islanding Compliance
Equipment must support IEEE 1547 anti-islanding requirements. Protective relays at the project tie need IEEE 1547 trip functions per the utility's interconnection agreement.
Natural Ester Fluid (NEF)
Many developers specify NEF (Envirotemp FR3, BIOTEMP) for environmental and fire-safety reasons. We build with either mineral oil or NEF — same lead time, modest cost premium for NEF.
Power Electronics, SMA, ABB, GE Renewable, Sungrow — every inverter has slightly different output characteristics. Send us the inverter model along with the transformer spec and we'll size the unit to match. Common errors: undersizing for inverter overload capability, missing the dual-secondary requirement on multi-inverter skids.
Typical Project Profile
Solar Farm (50 MW)
- 20× inverter step-up transformers (2.5 MVA each, 600 V → 34.5 kV)
- Project substation: 50 MVA step-up to utility transmission, 34.5 kV → 138 kV
- Collection switchgear at the substation, MV ring main
- NETA-compliant commissioning, IEEE 1547 protection setup
Wind Plant (100 MW)
- 40× wind turbine base transformers (3 MVA each, 690 V → 34.5 kV)
- Collection substation transformer + switchgear
- SCADA-integrated protection
Solar / Wind Project in the Pipeline?
We build inverter-duty pad-mounts and project step-up transformers from 1 MVA to 50 MVA.