Phase-Shifting Transformers Applications & Technology

Thomas Schmidt, ABB AG Transformers, Sept. 2016 Phase-shifting transformers Applications & Technology

. Introduction

. Why phase-shifting transformers? . Benefits to you . Quick pay-back period . Reliability

. Applications . Protect transmission lines . Increase transmission capacity . Load sharing

. Power flow control . Theory of electrical power flow control

. Technology . Phase angle regulation, transformer designs, tap changers,… . How to prepare a specification

. Examples/ references . Two-core, single-core designs, sound enclosures,…

Bad Honnef

Factory: Location: Bad Honnef, Germany Founded: 1906 Employees: 360 Revenues: 130 MUSD Deliveries: world-wide

Phase-shifting transformers • Up to 1630MVA • Up to 500kV • Up to +/- 80 degrees

Power transformers • Up to 1100MVA • Up to 500kV

Industrial transformers • Arc Furnace, Rectifier, Converter • Wide LV regulating range • LV current to hundreds of kA • Rated power up to 200 MVA • Rated voltage up to 400 kV

PST helps you . Improve your operating performance

. Increase total power flow in a given corridor w/o violation of N-1 criterion

. Remove bottle necks in the electrical grid

=> increase your revenues

. increase supply of power to the customer e.g. 100 MW for 2000 h/a can result in approximately

=> 4 MEuro/a revenues (at ~ 20 Euro/MWh)

. Load sharing Increase on parallel lines transmission capacity of . Control power flow lines between neighboring countries . Optimizing losses in transmission networks . Avoiding overloads Parallel transmission lines on transmission lines

Increase . Adding generation transmission G without increasing SC-power capacity of 3 substations . Push power G G over high-impedance line 1 2

New high impedance line

Block parasitic . Compensate angle difference power flow at municipal networks caused by additional infeeds . Block parasitic power flow G G G and overload caused by transmission angle differences in feeding network(s). 1 > 2 2

Cables dimensioned for radial flow

Split . Defined sharing of real power generation to different systems/ customers

Generation serves two networks

Connect . Allowing access of new generation (e.g. wind turbine parks, solar power, …)

. Independent Power Flow Increase Control on transmission lines without having control of generation

Protect . Protection against unplanned power flows

. Basis for selling transmission capacity

X . Phase shifting transformers are S L power flow controllers V V . The phase angle between two S L systems determine the power P  sin(S   L ) X exchange

VS - VL

X XT VS - VL S L I

VSVL VS VL P  sin(S L ) X  XT S - L + 

Two synchronous systems.

Transmision lines with different   impedances e.g. VS , S VL , L overhead / cable or 400 kV / 110 kV. PP L Transmision angle G difference S - L drives power flow G with unbalanced load G sharing of lines. L The low impedance line is overloaded, limiting the total transmission capacity of the corridor. L PST impose an L additional circulating L current, thus improving the balance of power P G flows. The total transmission capacity increases.

The phase shifter rotates In pure phase shifting the phasor orientation transformers a voltage in between the source and quadrature to the source load side. voltage is injected into the line

V V 3S V1L VL VS L V3L V1S S

adv

V2S V2L

Starting with a symmetrical three-phase V1S V1L system with a certain load flow

V2S V A PST shall be 2L used to control the load flow

V3S The PST takes a V3L fraction of the two neighbor phases

Combines them as a difference voltage

Which is then injected into the third phase

based on a picture from SETFO

Source voltage U V V e 1S V1L excites the Exciter transformer

U1e Tapped voltage of the neighbouring phases, optimised intermediate voltage to utilize the tap changer best

U1reg

The resulting quadrature

voltage uinj Will be transformed and will be u1inj injected between source and load (Voltage V)

Single-Core – Two-Core Single tank – Two tank Symmetrical – Non-symmetrical 90° regulation – 60° regulation

Two-Core . Quad Booster Single-Core . Extended Delta . Polygon, Squashed Delta . “always” except for different grounding . Up to Um 245 kV methods on S and L side . In networks with low short circuit power . May be unnecessarily large & expensive

. Two-Winding Transformer (wye-wye) . HV > LV

TransformationV of V1S 1L the injected voltage

V2S V2L

V3S V3L

Series transformer

Excited by the Tapped voltage of the neighbouring source voltage phases, optimised intermediate voltage

Exciter transformer

V1 V1 Excitation of the core by the S L phase voltage connected in  Delta A part of the resulting voltage V3L V2S between phase 2 and 3 Will be transformed and will be injected between source and load (Voltage V)

V V 3S 2L Single-core Delta connected winding Symmetric regulation Two set of tap changers

Single-core, V1S symmetric design

ue11 V1L

ue12

V2S

V2L

V3S

V3L

© ABB Group October 3, 2016 | Slide 35 Technology Non-symmetrical single-core design - extended delta V V1S V1L Excitation of the core by the phase voltage connected in  Delta A part of the resulting voltage V3L between phase 2 and 3

V2S Will be transformed and will be injected between source and V3S load (Voltage V)

V2L Single-core Delta connected winding Non-symmetric regulation One set of tap changers

V1S V1L

V2S V2L V

V3S V3L

A part of the resulting voltage between phase 2 and 3 Excitation of the core by the will be transformed and will be phase voltage connected in injected between source and Delta load (Voltage V)

. Power for which phase shifter is dimensioned depends on maximum phase angle

. Higher insulation demands

. Larger, more complex tapped windings

. Demanding specs on OLTCs: step voltages, switching power, reactance and capacitance of large tapped windings

. Phase shift in load currents on a given core limb cause additional stray flux, forces, losses

. Multitude of load cases to be checked for optimisation

.Control power flow? Detect power flow issues .Push power to Protect lines? different voltage level?

Description of What is required? limit, block, control, functionality balance power flow

Contact ABB prior tender Load flow studies Define necessary services & Situation MVA ~ phase angle ° transformer characteristics today & future

Transport .Project boundaries Installation .Time & Money

. T Develop technicalr transformer specification a n s f o r . Cm ue sr . t RequiredoM purpose/ functions of PST ma .Iterative process . en Technicalru needs f . Transformera environment c t . Boundaryu conditions (e.g. transport) r e . Draftr technical specification . Evaluation criteria (losses)

. Check list . Quick budgetary proposals .=> Optimized . Draft technical data specification . Technical comments & recommendations . Technical limits

Electrical Design of Phase Shifting Transformers for Tenders

Schritt 1: Selection of Concept

Inputs 1 Typical tap changer characteristics

tap changer, max switching max step Rated power, MVA P_S 75 MR equivalents cost EURO power kVA voltage kV Rated Source Voltage, kV US 154,5 VIII 525 1500 Rated Load Voltage, kV UL 154,5 M I 30000 3500 3,3 BIL, kV BIL 650 M III 30000 1500 3,3 BIL tertiary (test) winding, kV BIL_tert 150 R I 50000 6000 3 Max. no-load angle, degrees alpha 29 R III 60000 3000 4 Advance and retard angle required? adv_ret yes G I 226000 6500 5 Voltage regulation range % Volt_reg 13,75 G III 226000 5000 5 No. of steps fine regulating, angle N_angle 16 ARS 25000 0 no. of coarse reg. Windings, angle N_coarse 0 No. of steps (voltage) N_volt 11 frequent tap changing? n Base cost active part, EURO/MVA 7030 depends on voltage! +13% for single core designs! additional reactor % impedance, % extra_uk 0 estimated % impedance at max. angle, % estimated_max_uk 12 Overload, % Overload 0 Overvoltage, % Overvolt 0 When principle design has been chosen: save, then hit button! load power factor cos_phi 1

Outputs 1

Design asymmetric auto symmetric auto hexagonal grounded wye, two asymm YY, single delta delta core core Series Transformer ratio K 3,1 voltage across OLTC >80 kV!

Voltage phasor in V_S 89,2 89,2 89,2 89,2 89,2 Voltage phasor out V_L 102,0 89,2 89,2 89,2 102,0 load angle by PST impedance 6,8 6,8 6,8 6,8 6,8 max. advance phase shift under load a_adv_load 22,2 22,2 22,2 22,2 22,2 max. retard phase shift under load a_ret_load 35,8 35,8 35,8 35,8 35,8

Voltages and currents at max. angle,w/o overload and overvoltage quadrature booster voltage, kV delta_V 49,4 44,7 44,7 44,7 49,4 quadrature booster voltageunder load, retard, kV delta_V_max 64,4 54,9 54,9 54,9 64,4 rated I_source, A I_source 280,3 280,3 rated I_load, A I_load 245,1 280,3 280,3 280,3 280,3 rated I_regulating winding,in phase, A I_reg 245,1 271,3 230,8 156,6 280,3 rated I_regulating winding,out of phase, A 135,9 70,2 rated I_booster, A I_boost 90,4 rated excitation current at maximum angle, A I_excite 78,4 81,0 81,0 140,3

We develop a custom made transformer together with you!

. IEC 62032 / IEEE C12.135 double logo standard Guide for the application, specification and testing of PSTs

. IEC 60076-57-1202 Ed.1: Power transformers – Part 57- 1202: Liquid immersed phase- shifting transformers DRAFT ONLY (2015)

© ABB Group October 3, 2016 | Slide 53 ABB Phase Shifting Transformers Country of No. of Through- Rated Phase Angle Voltage Year of ABB Customer installation units Put Rating Voltage (No load) Regulation delivery Workshop/ [MVA] [kV] [degree] [%] Country

RWE Germany 4 350 400/ 120 +27 ±15 *2016 Bad Honnef, GER Alpiq Switzerland 4 150 380/ 220 ±10 ±10 *2015 Bad Honnef, GER Con Edison USA 1 575 345/ 345 ±40 2013 Bad Honnef, GER Con Edison USA 1 300 138/ 138 ±25 2013 Bad Honnef, GER Con Edison USA 1 300 138/ 138 ±25 2012 Bad Honnef, GER Transelec Chile 2 350 230/ 230 ±12 2011 Bad Honnef, GER RTE France 1 565 240/ 240 ± 27,5 2013 Bad Honnef, GER RTE France 1 63 66/ 66 +18/ -22 2011 Bad Honnef, GER Amprion Germany 1 600 230/ 230 ± 20 2011 Bad Honnef, GER EWZ Switzerland 2 250 220/ 150 ± 11,2 +15%,-21% 2010 Bad Honnef, GER REE Spain 1 1270 400/ 400 ±10 2010 Cordoba, ES REE Spain 1 750 230/ 230 ±30 2010 Cordoba, ES Steag Germany 1 150 110(65) ± 31 ± 16% 2008 Bad Honnef, GER AET Mendrisio Switzerland 1 400 400/ 155 ± 23.7 ± 13% 2008 Bad Honnef, GER ELIA Belgium 3 1400 400/ 400 ± 25 2007 Bad Honnef, GER TERNA Padriciano Italy 1 370 230/ 230 ± 32 2007 Bad Honnef, GER EWZ Switzerland 1 250 220/ 150 ± 11,2 +15%,-21% 2007 Bad Honnef, GER Montana Alberta Tie Canada 1 330 230/ 240 ± 79 2006 Bad Honnef, GER Austrian PowerGrid Austria 3 600 232 /232 ± 35 2006 Bad Honnef, GER Stw Ulm Germany 1 100 110/ 110 +7 2005 Bad Honnef, GER TERNA Rondissone Italy 2 1630 400/ 400 +18 2003 Bad Honnef, GER

© ABB Group October 3, 2016 | Slide 54 ABB Phase Shifting Transformers Country of No. of Through- Rated Phase Angle Voltage Year of Customer installation units Put Rating Voltage (No load) Regulation delivery Workshop / [MVA] [kV] [degree] [%] Country

Stw Saarbrücken Germany 1 90 110/ 110 + 42 ± 13% 2003 Bad Honnef, GER KeySpan USA 1 450 138/ 138 ± 58 2002 Bad Honnef, GER Commonwealth Edison USA 1 336 138/ 138 ± 30 ± 5% 2001 Bad Honnef, GER FURNAS - ANGRA Brazil 1 400 138/ 138 ±21 2000 Gual., BR Ontario Hydro Canada 2 845 240/ 240 ± 47 2000 Varennes, CA Detroit Edison USA 1 675 240/ 240 ± 47 2000 Secheron, CH Commomwealth EdisonUSA 1 336 138/ 138 ± 15 ± 5% 1999 Bad Honnef, GER Manitoba Hydro Canada 2 200 138/ 230 ± 60 1997/8 Varennes, CA EOS Switzerland 1 200 240/ 132 ± 9.6 ± 13.5% 1997 Secheron, CH Southwestern PS USA 1 150 120/ 120 ± 53 1996 Muncie, US Con Edison USA 1 234 138/ 138 ± 25 1996 Muncie, US Sierra Pacific USA 2 300 345/ 345 ± 58 1996 Muncie, US PSE&G USA 2 885 230/ 230 ± 32 1994 Muncie, US IFV Power Company Denmark 1 500 400/ 132 + 22 ± 12% 1993 Mannheim, GER New Brunswick Power Canada 1 225 138/ 138 + 30 - 1991 Mannheim, GER Commonwealth Edison USA 1 336 138/ 138 ± 15 ± 5% 1991 Muncie, US Utah P&L USA 1 302 230/ 230 ± 74 1990 Muncie, US Utah P&L USA 2 315 345/ 345 ± 75 1990 Muncie, US

© ABB Group October 3, 2016 | Slide 55 ABB Phase Shifting Transformers Country of No. of Through- Rated Phase Angle Voltage Year of Customer installation units Put Rating Voltage (No load) Regulation delivery Workshop/ [MVA] [kV] [degree] [%] Country

Nevada Power USA 2 336 345/ 345 ± 73 1990 Muncie, US WAPA USA 4 300 345/ 345 + 67 to - 60 1988 Muncie, US AGSM Verona Italy 1 60 220/ 130 ± 10 ± 10% 1984 Lignano, IT Saskatchewan Power Canada 1 200 250/ 230 ± 70 ± 20% 1981 Guelph, CA Montana Power USA 1 100 161/ 161 ± 60 1980 Muncie, US Montana Power USA 1 300 230/ 230 ± 60 1980 Muncie, US Ontario Hydro Canada 1 300 240 ± 40 ± 15% 1978 Guelph, CA AGSM Verona Italy 1 60 220/ 130 ± 10 ± 10% 1977 Lignano, IT Commonwealth Edison USA 1 336 138/ 138 ± 15 ± 5.5% 1977 Muncie, US Salt River Project USA 1 350 230/ 230 + 47 to - 32 1977 Muncie, US GKW Mannheim Germany 2 200 110/ 110 ± 20 - 1976 Mannheim, GER NWK Germany 1 300 220/ 220 ± 30 ± 5% 1975 Mannheim, GER Puget Sound P&L USA 1 400 118/ 118 0 to +21 ± 7.5% 1975 Muncie, US Ontario Hydro Canada 1 500 230 ± 40 ± 10% 1974 Guelph, CA PSE&G USA 3 672 230/ 230 ± 30 1973 Muncie, US PEPCO USA 2 150 135/ 135 ± 25 1972 Muncie, US Manitoba Hydro Canada 2 200 230/ 115 ± 60 1971 Guelph, CA

© ABB Group October 3, 2016 | Slide 56 ABB Phase Shifting Transformers Country of No. of Through- Rated Phase Angle Voltage Year of Customer installation units Put Rating Voltage (No load) Regulation delivery Workshop/ [MVA] [kV] [degree] [%] Country

LILCO USA 1 220 138/ 138 ± 10 1971 Muncie, US PSE&G USA 1 403 230/ 230 ± 25 1971 Muncie, US Con Edison USA 1 575 345/ 345 ± 25 1971 Muncie, US Cor. De Energia Elec. Perù 1 100 210/210 ± 20 ± 6% 1970 Lignano, IT Badenwerk & EVS Germany 1 300 220/ 220 ± 28 ± 10% 1968 Mannheim, GER Dow Chemical Canada 1 41,6 13,4 ± 15 ± 10% 1966 Guelph, CA Utah P&L USA 1 100 161/ 161 ± 30 1965 Muncie, US Idaho Power USA 1 300 230/ 230 0 to + 30 1965 Muncie, US Ontario Hydro Canada 1 300 240 ± 40 1963 Guelph, CA Con Edison USA 2 122 138/ 138 ± 25 1963 Muncie, US Hydro-Quebec Canada 4 150 230 1956 Guelph, CA

Total No. of units/ MVA 96 37.995

* = under commissioning ** = under construction *** = order received

Customer need . Control of power flow in the surrounding ring and into the city of Chicago . Avoiding parasitic power flow on the 138 kV cable network

ABB response . One 300MVA, 138 kV, ±15° Phase shifting transformer

Customer benefits . Increase the reliability of power supply

Customer: ComEd Year of commissioning: 2000 Project volume: one phase shifting transformer

Customer need . Control of power flow in the surrounding ring and into the city of Chicago . Avoiding parasitic power flow on the 138 kV cable network

ABB response . One 300MVA, 138 kV, ± 30° Phase shifting transformer

Customer benefits . Increase the reliability of power supply

Customer: ComEd Year of commissioning: 2001 Project volume: one phase shifting transformer

Customer need . New 138kV submarine cable connection in New York . Balance power flows in 345 kV and 138 kV systems. . Increase the power import capacity ABB response . One 450MVA, 138, ± 58° Phase shifting transformer with series reactor Customer benefits . Increase the reliability of power supply . Small increments of power flow, (64 taps)

Customer: Keyspan Year of commissioning: 2002 Project volume: one phase shifting transformer

Customer need . Increasing the import capacity from France to Italy . Meeting the n-1 criteria on the importing lines to Italy during high load ABB response . Two 400 kV, 1630 MVA, +18° phase-shifting transformers . Substation controls and automation Customer benefits . Increase the reliability of power supply . Increase of import capacity with cost savings of 1 MEUR/ month during a few months a year Customer: TERNA . Optimization of Year of commissioning: 2003 energy transmissions Project volume: 2 phase-shifting transformers, extension of substation and protection & control

Customer need . Reduction of unscheduled load flow . Increase of import capacity ABB response . Three units 400 kV, 1400 MVA, ± 25° phase-shifting transformers . 2 units with sound enclosure to reach 20 dB reduction

. Total weight of each transformer > 1.300.000 kg . Total foot print including cooling 36*18,5m Customer benefits . Better negotiation position within UCTE . Ability to purchase power at more reasonable prices Customer: Elia Year of . Increased reliability of the grid commissioning: 2008 Project volume: Three PS transformers, Protection & Controls

Customer need . Building first-ever merchant power transmission line . Control of power flow ABB response . System studies, basic specification . One unit 230 kV, 330 MVA, ± 79°, +5% phase-shifting and voltage regulating transformers . Protection and control Customer benefits . Please see www.matl.ca . Revenues by selling transmission capacity . Increase of system reliability

Customer: MATL Year of commissioning: 2009 Project volume: 345 kM, 300 MW, 230 kV line including the PST, protection & control

Customer need . Post contingency N-1 security . Decrease of short circuit current level . Control of parasitic power flow

ABB response . Up to five units (3 are contracted) 220/ 150 kV, 250 MVA, ± 11,2°, +15%, -21% phase-shifting and voltage regulating transformers . Monitoring

Customer benefits . Reducing the no of 220/ 150kV Substations Customer: EWZ . Increased reliability of network operation Year of commissioning: 2007 . Increase of feeder capacity under contingency conditions Project volume: Modification of Zurich’s feeder system on 220/150kV, including up to 5 PST’s

Customer need . Increase capacity of 225kV line between France and Germany . Balance cross-country power flow on two parallel lines . Avoid overload on French side ABB response . One phase shifting transformer Two-tank design 225/ 225 kV, 600 MVA, with ±20° phase angle regulation Customer benefits . Increased cross-country transmission capacity . Control of power flow . Balanced power flow on parallel lines Customer: Amprion Year of . Increased network reliability commissioning: 2011 Project volume: One PS transformer

Customer need . Increase transmission capacity of 230kV line in Santiago area . Avoiding circulating currents

ABB response . Delivery of two phase shifting transformers 230/ 230 kV, 350 MVA, with ±12° phase angle regulation . Delivery of phase shift angle control unit . Technical support for protection and control

Customer benefits . Increased electrical power flow without building new lines Customer: Transelec . Flexible power flow control Year of commissioning: 2011 . Improved system reliability Project volume: 2 PS transformers

Customer need . Maintain system reliability and control power flow within the New York City electrical network. . Compact design for standard transformer bays and transports within NY city limits ABB response . Outstanding design for complex requirements . Delivery of two phase shifting transformers with sound enclosure attached to the tank. 138/ 138 kV, 300 MVA, with ±25° phase angle regulation . Efficient design with low losses Customer benefits . Increased system reliability due to modern, compact and Customer: ConEd low sound regulating transformers

Year of . commissioning: 2012/ 2013 Standard foot print for easy installation at varies Project volume: 2 PS transformers substations

Customer need . Reliable power supply into the City of New York. Protect transmission lines into New York City and avoid overloads. . Large regulating range . Comply with strict NY sound level requirements ABB response . Complex design with gigantic hand made tap changers . Delivery of one two-tank phase shifting transformer with attached sound enclosure 345/ 345 kV, 575 MVA, with ±40° phase angle regulation Customer benefits . Control of power flow via modern regulating transformers with compact design, high efficiency and low sound Customer: ConEd levels Year of . Standard foot print for easy installation at varies commissioning: 2013 substations. Project volume: 1 PS transformers

Customer need . Control power flow on major transmission line between Italy and Switzerland . Distribute power from new hydro power plant ABB response . Delivery and installation of one 1-ph. phase shifter bank with spare unit, external cabling and monitoring 380/ 220 kV, 450 MVA, with ±10° phase angle regulation and ±10% voltage regulation . Low transport weight due to single-phase design Customer benefits . Increased reliability of network operation . Flexible regulation of power flow Customer: ALPIQ Year of commissioning: 2014 (still open) Project volume: One PS Transformer group