Distribution System DER Hosting Capacity IEEE34 PV usa.siemens.com/digitalgrid
Analysis Setup Hourly Load Flow Analysis Load Profile: Two Days Peak and Light For each class: Residential, Commercial, Industrial PV Profile: Single Ideal Sunny Day Distributed PV (PV at each load location) Utility Scale PV (Single PV at end of Feeder) PV Penetration Levels: 0, 20, 40, 60, 80, 100% of Peak Demand Page 2
Load Profiles Peak Days occur during Summer Weekdays Resident Peak occurs at 6 pm Commercial and Industrial Peak occurs at 12 p.m. Light Days occur during Fall Weekends Resident load is relatively flat through out the day time hours of the day Commercial and Industrial load is relatively flat through out the day 2 Load Locations - Small Industrial 4 Load Locations - Small Commercial 19 Load Locations - Residential Page 3
Solar PV Profiles Solar radiation occurs from 6 a.m. to 7 p.m. Maximum generation occurs at 12 p.m. and 1 p.m. Solar Profile obtained from NREL database for Arizona http://pvwatts.nrel.gov Page 4
Distributed PV Locations Solar PV at each load location with capacity as size of each maximum load and unity power factor Page 5
Distributed PV Results (Power) PV Integration Level % 0 20 40 60 80 100 0 20 40 60 80 100 Reverse Power Flow Phase A has the highest load followed by B and then C. A Load Balancing is recommended from Phase A to Phase C. Since the PV locations are distributed and proportional to the loads, the same phase unbalance exists for solar output. The Peak Day begins to have reverse power flow starting at 100% PV integration. The Light Day begins to have reverse power flow starting at 80% PV integration. Page 6
Distributed PV Results (Shifting of Supply Peak) PV Level % At Noon Peak Supply Peak Time Reducti on % 0 1.95 1.99 2 pm 0.00 20 1.51 1.69 7 pm 15.23 40 1.10 1.64 7 pm 17.90 60 0.70 1.63 8 pm 18.11 During the Peak Day, the peak load demand occurs during midday and so substation peak supply is greatly affected by integration of solar and is shifted to the evening. Reverse Power Flow 80 0.33 1.63 8 pm 18.11 100-0.02 1.63 8 pm 18.11 Reverse Power Flow PV Level % At Noon Peak Supply Peak Time Reducti on % 0 1.17 1.20 7 pm 0.00 20 0.77 1.17 8 pm 2.87 40 0.39 1.17 8 pm 2.87 60 0.04 1.17 8 pm 2.87 80-0.31 1.17 8 pm 2.87 100-0.63 1.17 8 pm 2.87 During the Light Day, the peak load demand occurs during evening and so substation peak supply is marginally affected by integration of solar. During midday, PV integration cause large amount of reverse power flow. Page 7
Distributed PV Results (Voltage) 1/2 Over Voltage During peak demand day, less than 10% of nodes are affected by low voltage. Under Voltage 19 hrs of the peak demand day there was at least one node registering a voltage below 95% There is no overvoltage at any time. There is some low voltage on all Phases during the peak day, down to 90.44%. During the peak day, less than 10% of nodes registered voltages below 95%. During the peak day, voltages below 95% is registered for about 80% of the day. Page 8
Distributed PV Results (Voltage) 2/2 Legend: 0% PV Level Peak Day at 12 pm 95% 100% 105% Node Voltage Range Area with voltage under 95% At maximum, 4 nodes experience low voltage issues 3 nodes are on primary side of the voltage regulators Page 9 1 node is on secondary side of distribution transformer
Distributed PV Results (Thermal Loading) There is no over loading at any time. Page 10
Distributed PV Results (Losses) For Peak Day, line loss decreases as PV penetration increases For Light Day, line decreases as PV penetration increases until there is large amounts of reverse power flow Page 11 PV Level % Total Line Loss (MWh) Peak Day Line Loss / Load (%) Total Line Loss (MWh) Light Day Line Loss / Load (%) 0 5.25 15.71 2.14 9.08 20 4.22 12.54 1.60 6.79 40 3.43 10.18 1.27 5.38 60 2.89 8.54 1.13 4.75 80 2.55 7.52 1.14 4.81 100 2.40 7.05 1.31 5.48
Utility Scale PV Locations Single Solar PV at end of longest three phase branch with capacity as size of total maximum load and unity power factor Page 12
Utility Scale PV Results (Power) PV Integration Level % 0 20 40 60 80 100 0 20 40 60 80 100 Reverse Power Flow Page 13 Phase A has the highest load followed by B and then C. A Load Balancing is recommended from Phase A to Phase C. Since a single three PV location is used, the phase is balanced. The Peak Day begins to have reverse power flow starting at 100% PV integration for Phase B and C. The Light Day begins to have reverse power flow starting at 80% PV integration for Phase C.
Utility Scale PV Results (Shifting of Supply Peak) PV Level % At Noon Peak Supply Peak Time Reducti on % 0 1.95 1.99 2 pm 0.00 20 1.52 1.69 7 pm 15.38 40 1.11 1.64 7 pm 17.85 60 0.72 1.63 8 pm 18.11 During the Peak Day, the peak load demand occurs during midday and so substation peak supply is greatly affected by integration of solar and is shifted to the evening. Reverse Power Flow 80 0.35 1.63 8 pm 18.11 100 0.01 1.63 8 pm 18.11 Reverse Power Flow PV Level % At Noon Peak Supply Peak Time Reducti on % 0 1.17 1.20 7 pm 0.00 20 0.77 1.17 8 pm 2.87 40 0.40 1.17 8 pm 2.87 60 0.05 1.17 8 pm 2.87 80-0.29 1.17 8 pm 2.87 100-0.61 1.17 8 pm 2.87 During the Light Day, the peak load demand occurs during evening and so substation peak supply is marginally affected by integration of solar. During midday, PV integration cause large amount of reverse power flow. Page 14
Utility Scale PV Results (Voltage) 1/2 Over Voltage During peak demand day, less than 10% of nodes are affected by low voltage. Under Voltage There is no overvoltage at any time. There is some low voltage on all Phases during the peak day, down to 90.44%. During the peak day, less than 10% of nodes registered voltages below 95%. During the peak day, voltages below 95% is registered for about 80% of the day. 19 hrs of the peak demand day there was at least one node registering a voltage below 95% Page 15
Utility Scale PV Results (Voltage) 2/2 Legend: 0% PV Level Peak Day at 12 pm 95% 100% 105% Node Voltage Range Area with voltage under 95% At maximum, 4 nodes experience low voltage issues 3 nodes are on primary side of the voltage regulators Page 16 1 node is on secondary side of distribution transformer
Utility Scale PV Results (Thermal Loading) There is no over loading at any time. Page 17
Utility Scale PV Results (Losses) For Peak Day, line loss decreases as PV penetration increases For Light Day, line decreases as PV penetration increases until there is large amounts of reverse power flow Page 18 PV Level % Total Line Loss (MWh) Peak Day Line Loss / Load (%) Total Line Loss (MWh) Light Day Line Loss / Load (%) 0 5.25 15.71 2.14 9.08 20 4.28 12.76 1.64 6.93 40 3.58 10.65 1.36 5.75 60 3.13 9.30 1.28 5.43 80 2.90 8.62 1.39 5.87 100 2.88 8.54 1.66 7.01
Conclusions The IEEE 34 feeder can host either Distributed or Utility Scale PV up to 100% (of peak demand) solar PV integration. 100% peak demand is 1.77 MW which is less than 20% of the feeder capacity (10 MW). No voltage violations occur due to solar PV. Distributed PV is able to help the low voltage issues where as the location of the Utility Scale PV doesn t affect the low voltage. No thermal capacity issues occur due to solar PV. Distributed PV is able to lower the maximum thermal loading where as the location of the Utility Scale PV doesn t affect the maximum thermal loading. Page 19
Contact Us Md. Masoom Chowdhury Consultant Siemens Power Technologies International E-mail: masoom.chowdhury@siemens.com Lina He Senior Consultant Siemens Power Technologies International E-mail: lina.he@siemens.com usa.siemens.com/digitalgrid Page 20