Inverter Duty Transformers
MARSONS GREEN | 1 MVA – 25 MVA | K-13 / K-20 Rated | Solar PV / BESS / VFD
MARSONS GREEN | 1 MVA – 25 MVA | K-13 / K-20 Rated | Solar PV / BESS / VFD
Solar PV inverters and battery storage inverters generate harmonic currents that standard transformers are not rated to handle. Connecting a conventional distribution transformer to a solar inverter system causes accelerated insulation degradation and premature failure — even at rated load. Marsons Inverter Duty Transformers are purpose-engineered for inverter-based sources: foil windings, K-factor rated insulation, multi-pulse harmonic cancellation, and unity power factor sizing.
Solar inverters produce 5th, 7th, 11th, 13th order harmonics causing additional winding heating not accounted for in standard transformer ratings. Marsons IDTs are K-factor rated (K-13/K-20 per IEEE C57.110) with foil windings that distribute harmonic currents uniformly.
Standard transformers are rated at 0.8 power factor. Solar inverters run at unity pf — meaning a standard transformer is undersized by 25% for solar duty. Marsons IDTs are rated at unity (1.0) power factor.
A distribution feeder averages 40–60% load. A solar IDT runs at or near rated load for 6–8 hours daily. Marsons IDTs are thermally designed for this continuous duty profile.
Marsons 3-winding or 5-winding IDTs with phase-shifted secondaries cancel dominant 5th and 7th harmonic orders at the MV bus — reducing Total Harmonic Distortion injected into the grid.
| Parameter | Value / Description |
|---|---|
| Rating Range | 1 MVA to 25 MVA (covers rooftop solar to 250 MW+ utility-scale parks) |
| HV Voltage Class | Up to 33 kV (grid injection at 11 kV / 22 kV / 33 kV) |
| LV Winding Voltage | 415 V / 690 V / 800 V / 1,050 V — matched to inverter AC output |
| Frequency | 50 Hz (India) | 60 Hz on request |
| Primary / Multi-Winding | Single secondary | 2 / 3 / 4 / 5 secondary windings (multi-pulse harmonic cancellation) |
| Cooling | ONAN / ONAF / OFAF — forced cooling for large MVA ratings |
| Winding Material | Aluminium Foil / Copper Foil (foil winding essential for harmonic current distribution) |
| K-Factor Rating | K-13 (standard solar duty) | K-20 (heavy harmonic / BESS / VFD duty) — per IEEE C57.110 |
| Power Factor Rating | Unity (1.0) power factor — NOT 0.8 pf. Critical for correct solar duty sizing. |
| Insulating Oil | Mineral Oil or Silicone Oil |
| Neutral Grounding | Solidly grounded or impedance grounded per site grid code (CEA regulations India) |
| For BESS Applications | 150% cyclic overloading capability for battery charge/discharge cycles |
| Standards | IS 2026, IEC 60076, IEEE C57.12.00, IEEE C57.110 (K-factor), CBIP Manual on Solar Transformers |
Handle rigorous harmonic profiles with precision. Marsons Inverter Duty Transformers seamlessly connect complex inverter outputs to the grid, offering advanced multi-winding designs and enhanced overload capabilities for solar and BESS applications up to 25 MVA.
Ground-mounted solar plants from 5 MW to 500 MW+. Central inverter and string inverter configurations.
Grid-scale battery storage for renewable firming, frequency regulation, and peak demand management. Enhanced 150% cyclic overloading.
Rooftop and ground-mounted captive solar for industrial and commercial energy consumers.
Industrial motor drive systems in steel, cement, mining, oil & gas — harmonic mitigation at the transformer.
Government scheme solar pump installations — compact, reliable IDTs for distributed agricultural solar.