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Phase-Shifting Transformers Applications & Technology

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Phase-Shifting Transformers Applications & Technology Thomas Schmidt, ABB AG Transformers, Sept. 2016 Phase-shifting transformers Applications & Technology © ABB Group October 3, 2016 | Slide 1 Welcome to the ABB Phase-shifting transformers © ABB Group October 3, 2016 | Slide 2 Phase shifting transformers (PST) Content . 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,… © ABB Group October 3, 2016 | Slide 3 ABB AG Transformers – Bad Honnef, Germany Phase-shifting transformers Short Introduction of Bad Honnef © ABB Group October 3, 2016 | Slide 4 Introduction ABB AG, Transformers, Bad Honnef, Germany Bad Honnef Factory: Location: Bad Honnef, Germany Founded: 1906 Employees: 360 Revenues: 130 MUSD Deliveries: world-wide © ABB Group October 3, 2016 | Slide 5 Introduction ABB AG, Transformers, Bad Honnef, Germany 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 © ABB Group October 3, 2016 | Slide 6 ABB AG Transformers – Bad Honnef, Germany Phase-shifting transformers Benefits © ABB Group October 3, 2016 | Slide 8 Why phase-shifting transformers? Benefits to you - higher revenues 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) © ABB Group October 3, 2016 | Slide 9 ABB AG Transformers – Bad Honnef, Germany Phase-shifting transformers Simulation of power flow © ABB Month DD, YYYY | Slide 14 Simplified grid model Power Flow w/o PST © ABB Month DD, YYYY | Slide 15 Simplified grid model Superposition of a Loop Flow © ABB Month DD, YYYY | Slide 18 ABB AG Transformers – Bad Honnef, Germany Phase-shifting transformers Applications © ABB Month DD, YYYY | Slide 19 Applications Increase transmission capacity . 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 © ABB Group October 3, 2016 | Slide 20 Applications Smaller scale applications 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 G Generation serves two networks © ABB Group October 3, 2016 | Slide 21 Applications Access to new generation (e.g. wind farm) 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 © ABB Group October 3, 2016 | Slide 22 ABB AG Transformers – Bad Honnef, Germany Phase shifting transformers Power flow control © ABB Group October 3, 2016 | Slide 23 Power flow control Theory 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 + © ABB Group October 3, 2016 | Slide 24 Power flow with phase-shifting transformers Optimization of load sharing and transmission capacity 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. © ABB Group October 3, 2016 | Slide 25 ABB AG Transformers – Bad Honnef, Germany Phase-shifting transformers Technology © ABB Group October 3, 2016 | Slide 26 Technology Rotating the voltage phasor 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 © ABB Group October 3, 2016 | Slide 28 Technology Basic principle 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 © ABB Group October 3, 2016 | Slide 29 Technology Basic principle 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) © ABB Group October 3, 2016 | Slide 30 Technology Electrical designs 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 © ABB Group October 3, 2016 | Slide 31 Technology Symmetrical two-core concept 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 © ABB Group October 3, 2016 | Slide 32 Technology Symmetrical single-core design - extended delta 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 © ABB Group October 3, 2016 | Slide 34 Technology Symmetrical single-core design - extended delta 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 © ABB Group October 3, 2016 | Slide 36 Technology Asymmetrical single-core design - extended delta 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) © ABB Group October 3, 2016 | Slide 37 Performance characteristics Differences to normal power transformers . 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 © ABB Group October 3, 2016 | Slide 41 ABB AG Transformers – Bad Honnef, Germany Phase-shifting transformers Specification © ABB Group October 3, 2016 | Slide 46 Technology Develop successfully a PST specification .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 © ABB Group October 3, 2016 | Slide 49 Phase Shifting transformer . 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
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