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© Fraunhofer IWES
Outcome of a Study conducted for the Bayernwerk AG
Innovative Reactive Power Management for Distribution Grids with High PV Penetration
Contact:
Thomas Stetz, [email protected] Kraiczy, [email protected] Wang, [email protected]
Results presented at the VDE ETG Conference „From Smart Grids to Smart Markets“, Kassel, Germany, 2015
© Fraunhofer IWES
Outline
Scope of the Study
High PV Penetration in Distribution Grids: Bayernwerk‘s Smart Grid Region „Seebach“
Seebach‘s Reactive Power Characteristic today
Expected future Reactive Power Characteristic
Central Reactive Power Management utilizing controllable MV PV-Systems
© Fraunhofer IWES
Scope of the Study
Background: PV at LV level shall contribute to static voltage support by means of reactive power provision!
Part 1 (Autonomous Reactive Power Provision): How would a bulk reactive power provision affect the reactive power
characteristic of a distribution grid?
What kind of autonomous reactive power provision method would be most suitable for LV application?
Part 2 (Centralized Reactive Power Management): Can controllable PV systems at MV level contribute to control the reactive
power exchange between MV (20 kV) and HV (110 kV) level?
© Fraunhofer IWES
Bayernwerk‘s Smart Grid Region „Seebach“
Smart Grid „Seebach“:• 15 PV-Systems at MV-Level (10.7 MW)• 1.450 PV-Systems at LV-Level (~30 MW)• Winter peak-load ~ 12.5 MVA
© Fraunhofer IWES
Bayernwerk‘s Smart Grid Region „Seebach“
Smart Grid „Seebach“:• 15 PV-Systems at MV-Level (10.7 MW)• 1.450 PV-Systems at LV-Level (~30 MW)• Winter peak-load ~ 12.5 MVA
© Fraunhofer IWES
Pow
er [M
W, M
var]
Q @
HV
/MV
Sub
stat
ion
P @ HV/MV Substation
Power Flows at the „Seebach“ 110/20kV Substation
© Fraunhofer IWES
IMPACT OF AUTONOMOUS REACTIVEPOWER PROVISION BY PV AT LV-LEVEL
Part 1
results by Markus Kraiczy, Fraunhofer IWES
© Fraunhofer IWES
Expected Q-Flows at 110/20 kV Substation
© Fraunhofer IWES
Expected Q-Gradients at 110/20 kV Substation
© Fraunhofer IWES
Expected Q-Gradients at 110/20 kV Substation
© Fraunhofer IWES
Summary
Bulk reactive power provision by LV PV systems can have a significant affect on the reactive power characteristic of the „Seebach“ grid
The fixed power factor method has the highest impact on the reactive power exchange with the upstream 110 kV grid
The CosPhi(P) method will lead to the highest reactive power gradients within the „Seebach“ grid
The Q(U) method shows the lowest impact on the reactive power exchange AND reactive power gradients
Q(U) method turns out to be the favorable option for static voltage support at LV level
© Fraunhofer IWES
CENTRAL REACTIVE POWER MANAGEMENT
Part 2
results by Haonan Wang, Markus Kraiczy (Konrad Diwold), Fraunhofer IWES
© Fraunhofer IWES
Technical Framework for Implementing Q-Management into Bayernwerk‘s Monitoring and Control Architecture
Goal: Establish a source of controllable reactive power for Bayernwerk AG
Consideration of MV PV-systems only
Reliable and stable operation
Low effort for integrating Q-management into existing monitoring and control architecture
Harmonization with local Q(U)-control
Avoid PV technology upgrades, if possible
© Fraunhofer IWES
Control Concept for Central Q-Management
© Fraunhofer IWES
Algorithm and Characteristics ΔQ(ΔQ)-Characteristic of central Q-Management
Extended Q(V)-Characteristic
Cen
tral
Q-M
anag
emen
t
3. Determine the Q-Setpoint deviation for controllable MV-DGs according to the
ΔQDG(ΔQHV)-Characteristic
5. MV-DG-Controller calculates the Q-Setpoint and limits it within the operation area according
to the extended Q(U)-Characteristic
6. Set the reactive power of MV-DG
1. Determine the target value of reactive power exchange at HV/MV-NCP (QHV_set)
4. Send Q-Setpoint deviation to the controller of MV-DGs
Optimized network state
2. Determine the current setpoint deviation of Q-Exchange at HV/MV-NCP (ΔQHV)
Loca
lQ-C
ontr
ol
© Fraunhofer IWES
Harmonization with autonomous Q(U) Control
© Fraunhofer IWES
Theoretical and Technical Potential
Grid A Grid B
Grid C Grid D Grid E
© Fraunhofer IWES
Summary
The proposed central Q-Management approach…
can be easily implemented into Bayernwerk‘s monitoring and control architecture only one external measurement value required
does not require any extensive controller parameterization only one central characteristic for all PV systems
harmonizes with the local Q(V) control no additional measurements for voltage control required
stable even under n-1 conditions
is a relevant source of controllable reactive power for Bayernwerk problem of intermittency can be overcome with Q@night functionality
© Fraunhofer IWES
Work in Progress…
Cost-benefit assessments and comparison with conventional reactive power sources
Real-time controller-in-the-loop tests
Implementation and field tests within the Bayernwerk service area
Your contacts for further information:
Thomas Stetz, [email protected]
Markus Kraiczy, [email protected]
Haonan Wang, [email protected]
© Fraunhofer IWES
Voltage Magnitudes at LV Level