Single-winding design for bulk transmission interconnection. Custom-engineered up to 600 MVA, up to 525/345 kV — built to IEEE C57 family, ANSI, and NEMA standards for grid operators, utilities, and EPC contractors.
| Category | Specification |
|---|---|
| Capacity Range | Up to 600 MVA |
| Phases | Single-phase and three-phase |
| HV Winding Voltage | Up to 525 kV |
| LV (Series) Winding | Up to 345 kV |
| Tertiary Winding | Delta-connected; available for reactive compensation and auxiliary supply |
| Typical Configurations | 345/500 kV, 230/345 kV, 138/230 kV, 115/230 kV |
| Tap Changer | On-Load Tap Changer (OLTC) standard; De-Energized (DETC) available |
| Neutral Grounding | Solidly grounded standard; NGR provisions available |
| Cooling Methods | ONAN / ONAF / OFAF (specified per load profile) |
| Winding Material | High-conductivity copper (standard) |
| Insulation Medium | Liquid-immersed mineral oil |
| Standards | IEEE C57.12.00, IEEE C57.12.10, IEEE C57.12.90, ANSI, NEMA |
| Compliance | Buy American Act (BAA), BABA, §303 Defense Production Act |
| Factory Testing | IEEE C57.12.90 routine and type tests; full test report included |
| Lead Time | 48 weeks |
| Manufacturing | United States |
LIMIK autotransformers are custom-engineered, liquid-immersed units designed for bulk transmission interconnection between EHV voltage levels. Built on a shared series/common winding architecture, they deliver higher efficiency and lower losses compared to two-winding designs — making them the preferred choice for 345/500 kV, 230/345 kV, and 115/230 kV interconnections across transmission networks.
Available up to 600 MVA at HV classes up to 525 kV and LV classes up to 345 kV — every unit is engineered to your specification. Neutral grounding, tertiary winding configurations, and reactive compensation arrangements are integrated at the design stage.
All units designed to IEEE C57.12.00 and IEEE C57.12.10 with on-load tap changers standard on transmission-class units. Factory-tested to IEEE C57.12.90. Buy American Act (BAA), BABA, and §303 Defense Production Act compliant on every order. Typical lead time: 48 weeks from signed specification to shipment.
Interconnecting 345 kV, 500 kV, and 525 kV systems across regional transmission networks — PJM, MISO, SPP, WECC, and SERC.
Step-up and step-down between EHV voltage levels: 115/230 kV, 138/230 kV, 230/345 kV, and 345/500 kV configurations.
New substation builds and capacity expansions requiring bulk EHV interconnection with tertiary winding provisions for reactive compensation.
Mission-critical EHV interconnection for DOD and DOE installations. §303 Defense Production Act and Berry Amendment compliant.
Autotransformer topology reduces copper and core losses versus equivalent two-winding units — resulting in lower lifecycle operating costs for high-capacity interconnection projects.
Delta-connected tertiary winding available for reactive compensation (capacitor banks, reactors), harmonic suppression, and station auxiliary power supply.
On-load tap changer standard for continuous voltage regulation under load. De-energized tap changer (DETC) available where specified.
Satisfies BAA, BABA, and Berry Amendment requirements. Eligible for DOD/DOE direct procurement under §303 Defense Production Act.
