1. Improving Power Delivery and Quality Through Secondary Voltage Control
Aleksandar Vukojevic, Manager – Emerging Technologies Office

2. Duke Energy – About us

3. Secondary Voltage Control – Brief History
Timeline
Fall 2013 – first pilot project with Varentec
130 ENGO-V units installed on 4 feeders
Use case: secondary voltage management in the vicinity of the 1.2MW PV Farm
Summer 2014/Summer 2016 – pilot project with GridCo
5 IPR devices installed at 5 feeders
Use cases: power quality improvements, residential solar high voltage mitigation, low voltage mitigation
Spring 2015/Sumer 2016 – pilot project with GridCo (SVC-20)
25 devices installed on 5 feeders
Use case: low voltage mitigation on CVR feeders and tobacco farm power quality improvement

4. In-Line Power Regulator (IPR)
Diode
Cell
Technical Characteristics:
Voltage: 240V, 1-phase
Nameplate: 50 kVA
Voltage Regulation: ±10%
VAR Regulation: ±5 kvar
Harmonic mitigation: 3rd, 5th and 7th
String

5. Metal Shredding Facility Distribution Transformer
Location Overview
Inverter
Metal Shredding Facility
Distribution Transformer
Traffic Lights

6. One Week Operational Data

7. Solar Array (IR) – First Inspection with IR camera

8. Voltages Before and After IPR Commissioning
Grid-Co device turned on

9. Voltage % THD Before and After IPR Commissioning

10. Voltage Flicker Before and After IPR Commissioning

11. Static VAR Compensator – SVC-20
Technical Characteristics:
Voltage: 240V, 1-phase
VAR Rating: 4 steps of 4.3 kvar
Control: Voltage or VAR

12. Project Objective – Low Voltage Mitigation
Project with EPRI
PI: Jason Taylor, PhD
PI: Surya Santoso, PhD Professor at University of Texas

13. SVC and IPR Placement – 15 SVCs and 1 IPR (Optimal Solution)
Siting Considerations
Undervoltage violations
Physical limitations
Transformer rating
Number and type of devices
Iterative placement

14. Simulated Feeder Voltages Before and After IPR and SVC Implementation

15. SVC and Capacitor Switching
Before
After

16. SVC Node Analysis

17. Reactive Power Injection on Summer Peak Day

18. The D-VAR® VVO Solution
What is it?
A 15kV class power electronic compensator that is installed on primary distribution networks in communities, business parks, or wherever enhanced power quality is beneficial
Why would a utility use it?
To save time & money by avoiding costly alternatives to strengthen the distribution grid
Example Applications
Increasing feeder-level solar hosting capacity (e.g., mitigating flicker caused by cloud pass & variability)
Balancing VARs in utility-owned microgrids
Achieving mandated efficiency upgrades (e.g., CVR)
Replacing voltage regulators to enhance power quality

19. The D-VAR® VVO Solution
Shunt power electronics modules
Continuous control of volt/VAR
Absorbs and supplies reactive power
3ph or 1ph application
Meets 15kV feeder standards
Standard 15kV protection gear
Pole mounted in feeders
Pad mounted option (5’x6’)
Acoustically Quiet
Tamper proof enclosure (sealed)
No routine maintenance (no mechanical switching, no pumps, fans, or filters)