1. Distribution Feeder Voltage Regulation and Control
W. H. Kersting
Milsoft Utility Solutions

2. Purpose of This Paper Present ANSI Voltage Standards
Present Step Voltage Regulator
What it is
Control Settings
Model
IEEE 13 Node Test Feeder
Steps in regulating voltage on the test feeder

3. The ANSI Voltage Standards
Range A
Nominal Utilization Voltage = 115 volts
Maximum Utilization Voltage = 126 volts
Minimum Service Voltage = 114 volts
Minimum Utilization Voltage = 110 volts
Range B
Maximum Utilization Voltage = 127 volts
Minimum Service Voltage = 110 volts
Minimum Utilization Voltage = 107 volts

4. ANSI Range A Critical Voltages

5. Voltage Drop Assumptions
1 Volt drop on the service drop
2 Volt drop on the secondary
3 Volt drop through the transformer
Minimum Voltage at the Transformer Primary Terminals will be 120 volts

6. Voltage Profiles

7. Step Voltage Regulator

8. Type B Step Voltage Regulator

9. The Step-Voltage Regulator Model

10. Three Phase Voltage Regulator Model

11. Model Matrix

12. Compensator Circuit

13. Control Panel

14. Control Circuit

15. Regulator Control Settings
Voltage Level – voltage to hold at the regulation point
R and X setting (volts) – Equivalent impedance from the regulator to the regulation point
Time Delay – time after a tap change required before the tap is changed
Bandwidth – allowed deviation from the set voltage level

16. Compensator Impedance

17. Equivalent Line Impedance

18. Bandwidth

19. IEEE 13 Node Test Feeder (Modified)

20. Modifications
Line 4-12 changed to phases B-C
Transformer 6-7 changed to Ungrounded Wye – Delta
Load at Node 7 converted to Delta-PQ
Load at Node 8 converted to Delta-PQ
Load at Node 14 changed to phase B with constant Z load
Load added at Node 5: j145.3 kVA

21. Step 1 Select regulation point to be Node 4
Run power-flow with source set to 126 volts
Display Voltage Profile
Compute compensator impedance

22. Step 1 Voltage Profile

23. Voltages and Currents from Power-Flow Run

24. Compensator R and X Settting

25. Full Load with Regs, no Caps

26. Observations Regulator taps Concern about high voltage at Node 2
Phase a: 11
Phase b: 12
Phase c: 15
Concern about high voltage at Node 2
Need to add shunt capacitors

27. Shunt Capacitors Source reactive power Install shunt capacitors
Phase A: 765 kvar
Phase B: 809 kvar
Phase C; kvar
Install shunt capacitors
Node 3: kvar per phases a,b,c
Node 4: kvar per phases a,b,c
Node 13: 150 kvar on phase c

28. Full Load with Regs and Caps

29. Observations Regulator taps Notice good voltage balance
Phase a: 5
Phase b: 6
Phase c: 7
Notice good voltage balance
All voltages between 120 and 122 volts at Node 4

30. 50% Load with all Capacitors

31. 50% Load with 900 kvar at Node 4 switched off

32. 10% Load Growth with original caps

33. 10% Load Growth 100 kvar per phase added at node 4

34. Questions?