Smart distribution system and automation, Diapositivas de Sistemas Eléctricos

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Integrated Volt VAR Control(IVVC)

David Lubkeman ECE 551

Smart Electric PowerDistribution Systems

 Topics Review Local-Measurement Based Controls  Coordinated Volt VAR Controls  VAR Dispatch for Substation Power Factor Control   Integrated Volt VAR Control (IVVC)IVVC Heuristic Control Example  Conservation Voltage Reduction (CVR)  Simulation   Bellwether measurements with Smart MetersFeeder conditioning  OpenDSS and WindMil Examples

 Volt/VAR Control for distribution circuits is often mentioned Background  as a key application for Smart Grids.Important to understand:   How capacitor banks are used to compensate for load VARsWhy switched capacitors are needed   Local (decentralized) control strategies for switched capacitorsControl strategies for coordination line voltage regulators withswitched capacitors  This material will review decentralized and centralized Volt VARcontrol and implementation that can be realized using today’stechnology.

Benefits of Capacitor VAR Compensation

1. 2. Reduce line resistance power (I squared R) lossesImprove voltage profiles (by reducing voltage drop)
2. Reduce power demand on generation during peak loadconditions ($/kW peak)
3. Capacity release – deferral of capital expenses related toneed for increasing supply kVA rating ($/kVA)
4. Support transmission line voltages during heavy loadingconditions Can effectively add Capacitive kVAR up to point where top offeeder VAR flow is about zero.

Sample Circuit from Capacitor Lectures

  Note load is being modeled as constant powerIterative technique being used to solve for voltage

Line Resistance Line Inductance Id Load Iq Load

V load+

SourceVoltage

I load

CapacitorBank,Icap

kVAR

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time Hours

Line Loss (kW) Load Voltage (kV)

Base Case – No Capacitors  Voltagedropchanges inversely toload  Lossincreaseswith square of current

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time Hours^ Source kVAR^ Load kW

1. Volt VAR Control Schemes Local Control (based on locally available measurements)
2. 3. VAR Dispatch (using One-Way Communications)Integrated Volt VAR Control (IVVC)
3. Conservation Voltage Reduction (CVR) – subset of IVVC

Local Capacitor Switch Control Control Options  Voltage   TimeTemperature   CurrentReactive Power Switched Capacitor Control

Source Side Load Current Load Side VoltageLocal+

• CapacitorControl

Volts Current Temperature

Capacitor Control Vendors

Beckwith M-6280ACapacitor Control^ Cooper Cannon CBC-8000^ S&C Electric IntelliCap Plus

SEL-734 Capacitor Bank Control HD Electric

Local Control Setpoint Calculations Use power flow tool for control setpoints (up to you to test settings)

 Beckwith Examples: Time switching Capacitor Control Set-Up - Time

 Beckwith Examples: VAR Control Capacitor Control Set-Up – VARS (PF)

Example Application  Note howcapacitorswitching correlatesto loadprofile  kVAR flowonsubstation beingforced totarget VAR or PowerFactortarget David Lubkeman (North Carolina State University)^ Can simulate in OpenDSS with capacitor controllers ECE 551 Smart Electric Power Distribution Systems (^19)

 Improvement of substation Power Factor Impact of VAR Dispatch    Reduction of electrical kW lossesReduces peak demand on the substationImproves situation at G&T level by reducing VAR flow   Indirect control of Feeder VoltageFinancial benefits include reduction in kWh losses ($/kWh) and capacity release in  Switching on downstream capacitor will raise feeder voltage profiles   kW ($/kW benefit).Also get additional information on health of capacitors, reducing inspection costs.To achieve both a reduction in losses and load, the system needs an integrated voltage regulator and VAR control approach.