PST
Phase-shifting transformer
PST
- Controls active power flow in meshed and heterogeneous grids (e.g. renewable feed-in) — avoids line overload and increases usable active power capacity
- Single-core design (extended delta / hexagonal) for economy at system voltages up to approx. 230 kV; two-core design keeps tap winding and OLTC off the line terminals for greatest operating security above 230 kV
- ±60° phase-angle regulation with ±10% voltage regulation realized on a 300 MVA, 240/240 kV dual-tank utility reference unit (Canada, 2021) with 400 MVA emergency overload capability — reference-unit values, not family limits
- Built at the Weiz (Austria) lead factory for phase-shifting transformers to IEC 60076 and ANSI/IEEE; Sensformer digital monitoring features available
Active power flow controlMeshed transmission gridsRenewable power feed-inLine overload preventionControlled power transfer
Sign in to see your price, availability and framework terms for PST.
Horizon-3 pattern: this exact page gains commerce powers on sign-in — the URL never changes.
SIMULATED · ASK-AN-EXPERT PILOT DEMO
Ask an expert about PST
15 minutes with the right transformers specialist — question in, booked call out. No email archaeology.
Checking availability…
Specifications
Main
| Product type | Phase-shifting transformer (PST) |
| Function | Active power flow control in transmission grids |
| Applications | Meshed / heterogeneous power grids, renewable power feed-in, controlled power transfer, avoidance of line overload |
| Design variants | Single-core/single-tank and two-core/dual-tank designs |
| Lead factory | Weiz, Austria (also Nuremberg, Linz, Jundiaí) |
Electrical ratings
| Rated power | ≤ 2,000 MVA |
| Voltage class | ≤ 765 kV (single-phase units) |
| Phase-angle regulation | Project-specific; up to ±60° realized (300 MVA reference unit) |
| Voltage regulation | ±10% (reference unit) |
| Frequency | 50 / 60 Hz |
| Impedance | Two-core: design value at zero tap (e.g. 12%); single-core: zero at neutral tap |
Design, cooling & monitoring
| Tap changer | On-load tap changers (OLTC); e.g. six 1-ph OLTCs on dual-tank reference unit — two-core design keeps OLTC unexposed to system disturbances |
| Cooling | ONAN / ONAF / OFAF / ODAF oil-air, OFWF / ODWF oil-water (reference unit: ONAN/ODAF) |
| Overload | Emergency overload capability per specification (reference: 400 MVA from 300 MVA rated) |
| Digital monitoring | Available as Sensformer with digital features |
Standards & certifications
| Standards | IEC 60076; ANSI/IEEE; further national standards (BS, AS, NEMA, NF, CSA) per factory |
| Factory certifications | ISO 9001:2015, ISO 14001:2015, ISO 45001:2018 (Weiz lead factory) |
Options & variants
Design comparison from Siemens Energy 'Power Transformers' portfolio presentation FY2025 (phase-shifting transformer slide). Configuration is engineered per project.
| Design | Impedance at neutral/zero tap | Tap winding | Typical application |
|---|---|---|---|
| Single-core / single-tank | Zero (classical PST: extended delta, hexagonal) | In the line end; several internal CTs in leads required for full protection | Economic advantages at system voltages up to approx. 230 kV |
| Two-core / dual-tank | Given design value at zero tap (e.g. 12%) | Tap winding and tap changer not directly connected to line terminals | Greatest operating security above 230 kV — OLTC not exposed to system disturbances |
Documents & downloads
Brochure Power transformers — machine and network transformers from 30 to over 1,300 MVA
Presentation Power Transformers portfolio presentation FY2025 (incl. phase-shifting transformer section)
Also covered in the technical library
Brochure Transformers digitalization — Noedra Node suite for substation digitalization
