The document discusses the development of a multi-terminal power hardware-in-the-loop test bench for power system stability analyses focused on distributed generation. Large increases in inverter-coupled generators like PV and wind are changing power networks, challenging assumptions of conventional stability assessment. The test bench aims to holistically simulate transmission and distribution networks to evaluate stability with more inverter-based generation. It will integrate real inverters using power hardware-in-the-loop simulations to verify their influence on stability at a higher level of detail than software models alone.

1. © Fraunhofer IWES
Slide -1- Ron Brandl Project: DEAstabil
Multi-Terminal Power Hardware-in-the-Loop
Test-Bench for Power System Stability
Analyses Focused on Distributed Generation
RT15
Berkeley, CA | 13 - 14 June, 2015
Authors: Ron Brandl, Fraunhofer IWES
Dominik Geibel, Fraunhofer IWES

2. © Fraunhofer IWES
Slide -2- Ron Brandl, Project: DEAstabil
Multi-Terminal PHIL Test Bench for Power
System Stability Analyses
Content
1. Introduction
2. Power System Stability (PSS)
3. Simulation Environment
4. Hardware Environment
5. Power Hardware-in-the-Loop (PHIL) Simulation
6. Conclusion

3. © Fraunhofer IWES
Slide -3- Ron Brandl Project: DEAstabil
1. Introduction
Motivation
 Large increase in inverter-coupled generating units
 In Germany over 50% of power generation is from PV and wind at certain times
Change of future network
 Loss of spinning reserves
 Decentralization of power production
 Future mix of power plant park will
be inverter-dominated
 Power system stability (PSS)
has to be assured
Transformation to inverter-dominated networks
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Conventional Production > 100MW Wind Solar
18th April 2013 in Germany

4. © Fraunhofer IWES
Slide -4- Ron Brandl Project: DEAstabil
2. Power System Stability
Conventional PSS
 Focused on rotating generators
 Rotor angle stability
 Frequency stability
 Voltage stability
 Reconsideration of conventional
stability assessment Source: Definition and Classification of Power System Stability, IEEE/CIGRE Joint
Task Force, P. Kundur et. al.
Definition of Stability

5. © Fraunhofer IWES
Slide -5- Ron Brandl Project: DEAstabil
2. Power System Stability
Factors for network imbalance
 Failure/blackout of
 central power plants
 large loads
 transmission line
 HVDC terminals
 Switching operations on transmission network
 Weather influence
 Change of active coupling points of the interconnection to boundary networks
Scenarios for different PSS disturbances

6. © Fraunhofer IWES
Slide -6- Ron Brandl Project: DEAstabil
2. Power System Stability

7. © Fraunhofer IWES
Slide -7- Ron Brandl Project: DEAstabil
3. Simulation Environment
Intention of new simulation
platform
 Holistic simulation of transmission
and distribution network for stability
studies
 Include dynamics of decentralized
generators in the distribution
network
 Ability to conduct real-time
simulations, esp. PHIL simulations
 Evaluation of the future needs of
the power system, with increasing
inverter-based generation, on a
scientific basis
Motivation

8. © Fraunhofer IWES
Slide -8- Ron Brandl Project: DEAstabil
3. Simulation Environment
German interconnection network
 Holistic stability analyses required
 >> 100.000 nodes and machines from
high voltage down to low voltage level
Handling
 Aggregated models of distribution
networks with dynamic behaviors
 Development of models ≤ 110 kV
which are scalable and containing the
influence of distribution generators
 Verification of network models based
on available data of real network
disturbance
Dynamic Model of Distribution Networks

9. © Fraunhofer IWES
Slide -9- Ron Brandl Project: DEAstabil
3. Simulation Environment
Benefits/Summary
Advantage
 Use of self-made simulation models
 Access to calculation equations and simulation routine
Challenges
 Development of a holistic interconnection network simulation
 Real-time capability and compatibility with real-time products
 Parallel simulation on different cores is necessary, due to high numbers of nodes
General Benefits
 Flexibility  total access for developer possible
 Scalability  Level of detail user defined
 Expansion to new research fields

10. © Fraunhofer IWES
Slide -10- Ron Brandl Project: DEAstabil
4. Hardware Environment
Laboratory Test bench
Power Hardware-in-the-Loop test bench
 Development, construction and operation
of PHIL test Bench
 Demonstration of the contribution of
distributed generators (DER) to power
system stability in a laboratory environment
 Verification of the influence of power-
stabilizing control method from inverter-
based generators by coupling real-time
simulations with larger transmission and
distribution networks

11. © Fraunhofer IWES
Slide -11- Ron Brandl Project: DEAstabil
4. Hardware Environment
Laboratory (under preparation)
 Systec Laboratory, Fraunhofer IWES
 Power Hardware-in-the-Loop test bench
 Ametek, Power amplifier, 3x 3phase 90 kVA (single/parallel operation)
 Scienlab, DC-source (battery emulator), 290 kW
 TriPhase, DC-DC-AC inverter, 2x 15 kVA

12. © Fraunhofer IWES
Slide -12- Ron Brandl Project: DEAstabil
5. Power Hardware-in-the-Loop Simulation
Benefits/Summary
Intention of Power Hardware-in-the-Loop simulation
 Integration of „black box“ devices for stability support (e.g. converters)
 Level of detail increased due to use of the real hardware in comparison to software
models
 All effects of the hardware can be monitored

13. © Fraunhofer IWES
Slide -13- Ron Brandl Project: DEAstabil
5. Power Hardware-in-the-Loop Simulation
Network Simulation Scheme
German interconnection
network
 Transmission level
 2.000 nodes
 1.000 machine
 Distribution level
 Aggregated models
 4.500 active nodes
 4.000 machines
 Connection point HUT
 Current feedback circuit

14. © Fraunhofer IWES
Slide -14- Ron Brandl Project: DEAstabil
5. Power Hardware-in-the-Loop Simulation
Simulation platform
Controlled execution
 Higher-ranked phasor simulation
 Transmission network simulation
 Adaption/Integration of self-made
models
 Classified aggregated distribution
network
 Distributed generator
 Wind park
 Photovoltaic system
 CHPs
 HVDC link
 …

15. © Fraunhofer IWES
Slide -15- Ron Brandl Project: DEAstabil
6. Conclusion
Summary
Summary
 Reconsideration of power system stability
 Focusing of inverter-dominated generators in future
 Creating of holistic network simulation for stability analyses
 Scenarios of conventional PSS
 Research of new/upcoming PSS
 Power Hardware-in-the-Loop
 Laboratory Test – “Black Box” or self-programmed inverter testing
Outlook
 Network simulation for stability studies
 Development of new control strategies for DER
 Advanced test platform for DER

16. © Fraunhofer IWES
Slide -16- Ron Brandl Project: DEAstabil
Thanks for your attention
Ron Brandl
Fraunhofer Intitute of Wind Energy and Energy System Technologies
Koenigstor 59
34119 Kassel/Germany
Ron.Brandl@iwes.fraunhofer.de
Acknowledgement
We acknowledge the support of our work by the
German Ministry for the Environment, Nature and
Nuclear Safety and the Projekträger Jülich within
the project “DEA-Stabil: Beitrag der Windenergie
und Photovoltaik im Verteilungsnetz zur Stabilität
des deutschen Verbundnetzes” (FKZ 0325585).