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“Possible Effects of SG Functions on LTC Transformers” Monday, May 17, 2010 - 1:00 p.m.

“Possible Effects of SG Functions on LTC Transformers” Monday, May 17, 2010 - 1:00 p.m. Tom Jauch Life Senior Member, IEEE Application Consultant - Beckwith Electric Co. Largo, FL. Volt / Var / kW Management Objectives.

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“Possible Effects of SG Functions on LTC Transformers” Monday, May 17, 2010 - 1:00 p.m.

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  1. “Possible Effects of SG Functions on LTC Transformers”Monday, May 17, 2010 - 1:00 p.m. Tom Jauch Life Senior Member, IEEE Application Consultant - Beckwith Electric Co. Largo, FL

  2. Volt / Var / kW Management Objectives • Reduce losses (kW & kvar)(even kW thru an inductance creates vars) • Increase Power Delivery Capacity • (Deliver kvars locally) • Minimize Voltage Variations(With X/R=4, kvar causes 4x Vdrop of kW) • Reduce maintenance costs • (Less tapchanges – field setting changes) • Reduce/defer capital spending • Reduce operating costs • CONSERVATION VOLTAGE CONTROL (CVC)

  3. Effects of SG Functions: • Numerous SG Distribution System Configurations- Increased equipment duties • Conservation Voltage Control (CVC) Effects- Increased equipment duties • Dynamically Changing “Area of Responsibility” Effects- Increased equipment duties • Distribution Tie Transformer Applications- Tapchanges – var vs voltage effects • Capacitor Control- Reduced Tapchanger duties • Reverse Power Applications

  4. Expected SG operating requirement Additions / Revisions MORE available information on individual customer voltages & system conditionsExamples - SMART Meter reporting - Widespread IED’s - Extensive Communications NOTE: Local equipment controls must be capable of SAFE operation with any Communication interruption. Therefore local controls must also be capable of recognizing communication failure conditions. (Heartbeat)

  5. Expected SG operating requirement Additions / Revisions MORE available information on individual customer voltages & system conditions More / Faster Distribution system configuration changes to achieve added efficiency and lower energy costs Increased equipment duty cycles from closer tolerances on system conditions (voltage?) Coordination of Distribution system loading with RENEWABLE, DISTRIBUTED energy sources Example – one feeder with solar – another with wind

  6. Wind Farm Output Example Different “DAYS” NOT Separate units

  7. Typical Radial Distribution System DG

  8. Managing changing circuit configurations Alternate Feed Application

  9. Managing changing circuit configurations Distributed Generation ON or OFF or Partial DG DG DG

  10. Managing changing circuit configurations Load Transfer Application

  11. Managing changing circuit configurations Parallel Distribution Transformers Application

  12. Managing changing circuit configurations R DG DG DG DG DG R R R R R R R Possible SG Distribution System ??

  13. Volt/var MGMT EQUIPMENT * LTC Transformers* LTC Substation & Line Regulators* Substation Capacitor Banks* Distribution Line Capacitor Banks

  14. SG Enhancement – EXAMPLE Conservation Voltage Control CVC Application

  15. Basic LTC Control Action

  16. LTC Area of Responsibility V VD=3v VD=5v VD=7v VD=2v

  17. CONSERVATION VOLTAGE CONTROL (CVC) (Minimizing loads by minimizing voltages) Dynamically control (minimize) distribution customer voltage levels within 114v to 126v range Recent 3 YR Study Results: (without customer complaints!) www.rwbeck.com/neea Typical substation (average) – 1% VR reduced ENERGY (kWhr) by 0.86% 1% VR reduced KVAR load by 4% ------------------------------------------------------------------------------------ Typical substation results: Total possible energy savings = 1 - 3% Total kW demand reduction = 2 - 4% Total kvar demand reduction = 4 - 10%

  18. BUS Voltage Control Feeder Voltage Profile VD=3v BUS VD=7v VD=5v VD=2v 126v 125v 124v 122v VD=7v 118v Min Volts First customer Mid-line customer Last customer 117v Assumptions: Acceptable customer voltage = 114v to 126V Allowable minimum primary voltage = 117V

  19. BUS Voltage Control Common Setting Practice BUS 126v VD=7v 125v 124v Regulated Voltage Range – Full Load 122v 118v 117v First customer Mid-line customer Last customer Min Volts 125v setpoint +/-1v

  20. BUS Voltage Control Common Setting Practice BUS 126v VD=7v 125v 124v Regulated Voltage Range @ no load Regulated Voltage Range – Full Load 122v 118v 117v First customer Mid-line customer Last customer Min Volts 125v setpoint +/-1v NOTICE: ZERO LTC tapchanges over load cycle !!

  21. BUS Conservation Voltage Control Control Setting BUS VD=7v 126v 125v 124v 122v Regulated Voltage Range @ no load 118v No load 117v First customer Mid-line customer Last customer 118v setpoint +/-1v: LDCZ=7v (No Load) + (MAX Voltage drop)

  22. BUS Conservation Voltage Control Control Setting BUS VD=7v 126v 125v 124v Regulated Voltage Range – Full Load 122v Regulated Voltage Range @ no load 118v No load 117v First customer Mid-line customer Last customer 118v setpoint +/-1v: LDCZ=7v (No Load) + (MAX Voltage drop) NOTICE: MANY LTC tapchanges over load cycle !!

  23. BUS Conservation Voltage Control Feeder Voltage Profile 50% Load BUS 126v VD=7v 125v 124v 50% load 122v 118v 120.5v First customer Mid-line customer Last customer 117v Conservation Setting 118.5v setpoint +/-1v : LDC-Z = 7v Common setting 125v setpoint +/-1v 3.5V Reduction = 3%

  24. BUS Conservation Voltage Control Feeder Voltage Profile 50% Load BUS 126v VD=7v 125v 124v 50% load 122v 118v 120.5v First customer Mid-line customer Last customer 117v Conservation Setting 118v setpoint +/-1v : LDC-Z = 7v Common setting 125v setpoint +/-1v 3.5V Reduction = 3%

  25. BUS Conservation Voltage Control Feeder Voltage Profile 50% Load BUS 126v VD=7v 125v 124v 50% load 3% 122v 118v 120.5v First customer Mid-line customer Last customer 117v

  26. 4 – Distribution-Tie Transformer Application (LARGE DG) Utility System Large, var capable DG LTC Transformer or Regulator

  27. 4 – Distribution-Tie Transformer Application (LARGE DG) DPI(1) = 2% DPI(2) = 2% VARS XT =10% VARS EXAMPLES: Case 1 – DPI(1) = DPI(2) = 2%; XT = 10%; GOAL = Raise T2 by 1% Result: (VAr flow = 7.14%) VT2 > 0.143% VT1 < 0.143% VXT = 0.714% REQUIRES 7 -1% taps to Raise V2 by 1% Which also LOWERS V1 by 1%

  28. Anyone Getting A Better Appreciation of This ?? R DG DG DG DG DG R R R R R R R Possible SG Distribution System ??

  29. Pole top capacitor banks (SWITCHED)

  30. GEN Basic Premise • Poletop capacitor banks are for offsetting distribution system Var requirements • which REDUCES CURRENT • which also • reduces losses (I2R) • reduces voltage variation • reduces consequential VArs (I2X) • increases equipment capacities

  31. Important Considerations • Effects of VAr loads on Voltages! • Distribution Feeders: • * Feeder X/R Ratio (3 - 5) • * Load Power Factor • Feeder Voltage Profiles • * NUMBER OF REGULATOR TAPCHANGES ! • -------------------------------------------------------------------------------- • Substation Bus: • *Transformer X/R Ratio (25-50) * Load Power Factor • * NUMBER OF LTC TAPCHANGES !

  32. System var Control CAN dramatically REDUCE the number and frequency of LTC and Regulator Tapchanges required ! A SMART GRID FUNCTION !

  33. Read the Paper ! Reverse Power Effects High Penetration DG

  34. CONCLUSION • As SG is integrated into distribution systems, equipment operating duties will change. • LTC Transformers, as a primary Volt/var Management device, will see extensive added function. • Distribution var control will valuable in reducing LTC operations. • Conservation Voltage Control will add to LTC duties. • High penetration DG application will add to LTC duties. • Intelligent Local SG Control Backup is imperative.

  35. “Possible Effects of SG Functions on LTC Transformers”Q & AMonday, May 17, 2010 - 1:00 p.m. Tom Jauch Life Senior Member, IEEE Application Consultant - Beckwith Electric Co. Largo, FL

  36. Anyone Getting A Better Appreciation of This ?? R DG DG DG DG DG R R R R R R R Possible SG Distribution System ??

  37. 110KV T1 T2 15KV G1 G2

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