Testing an IEC61850 compliant
voltage control algorithm,
using a real-time simulation

Munich, 7-8 June 2016
Frank Marten, Sebastian Wende – von Berg
Fraunhofer IWES, Kassel
frank.marten@iwes.fraunhofer.deFrank Marten, Sebastian Wende – von Berg
© Fraunhofer IWES

Table of contents
 Introduction
 OpSim SecVer Testing a SecVer voltage controller with OpSim
 SecVer control algorithm
 Simulation scenario
 Results
 Conclusion, discussion

Frank Marten, Sebastian Wende – von Berg
© Fraunhofer IWES

Introduction (1/3) - OpSimMotivation
In reality, many parallel actors (TSOs, DSOs, VPPs,…) control generators, storages, loads andcompensator equipment in power grids
Common practice in many studies on this topic(often due to simulation tool inflexibility): just one grid voltage level is considered forgrid optimization/simulation
 just one grid topology, weather data set orplant type is applied per investigation
 VPP control strategies neglect the grid
topology altogether

Frank Marten, Sebastian Wende – von Berg
© Fraunhofer IWES

Introduction (2/3) - OpSim
The OpSim–project: Fraunhofer IWES and theUniversity of Kassel
 Industry consortium: 11 known
companies, from grid operation
to energy management
 Governmental funding (BMWI),2013-2017
Result:A real-time testing platform forsmart grid control strategies
 Simulator for large-scale
power networks
 A flexible architecture toconnect multiple controllers
 Scenario-data from weather
databases & forecast tools
www.opsim.net
Frank Marten, Sebastian Wende – von Berg
© Fraunhofer IWES

1Opal RT image source: http://www.opal-rt.com
2Python image source: https://pypi.python.org/pypi/PYPOWER

Introduction (3/3) - SecVer
Goals of the project:
 Implement methods to estimate
the distribution grid state fromPMUs
 Design of a distribution area
monitoring system (DAMS) Design of a control method forsafe operation of distribution grids(DACS) Design of a monitoring and control
system for distribution grids(DAMCS) Validate DAMCS throughsimulations and field tests
www.secver.de
Image source (top panel): www.secver.deFrank Marten, Sebastian Wende – von Berg
© Fraunhofer IWESSecVer control algorithm (1/3)
Q-control algorithm

The grid-control algorithm:
 Uses (re)active power from distributed powersources (e.g. diesel, battery) to:

RESTinterface

 minimize grid losses solve bottlenecks

C37.118
Server meet reactive power demand at PCC
 perform local voltage control
 Optimization routine based on SLSQP,
implemented in Python
 Communicates with lab-equipment via PMUs,
RTUs and standardized interfaces
 Real-time operation every 10 seconds

Image source: Fraunhofer IWES
Python logo source: www.python.org
Ogema logo source: ogema-source.net

Frank Marten, Sebastian Wende – von Berg
© Fraunhofer IWES

DatabaseIEC 61850
clientPMU

RTU

Lab grid (20/0.4 kV), IWES Systec
Left to right:
Li-battery
battery inverter (540 kVA, 500 kW)
6 test loads (2x200 ohm, 4x100 kvar)
diesel genset (200 kVA, 183 kW)

SecVer control algorithm (2/3)
Q-control algorithm

Before connecting it to the lab…

 Perform „offline tests“ with real-time
grid simulation (OpSim)

RESTinterface

 Use „almost“ the same interfaces as thelab test

Database

 Use a simulation scenario (controllableDGs) similar to lab test

IEC 61850
client„RTU“„PMU“-> Identification of possible bugs in thealgorithm, or optimization of controlparameters!

IEC 61850
serverDatabase
OpSim-proxy
Message Bus

Python logo source: www.python.org
Ogema logo source: ogema-source.net
Opal-RT Hardw are Picture: www.opal-rt.com

Frank Marten, Sebastian Wende – von Berg
© Fraunhofer IWESSecVer control algorithm (3/3)
Why use a real-time simulation to test thecontrol algorithm?
Static simulation (load flows) Only “snapshots” of the grid are analyzed
 Set points of voltage controller are sent tosnapshot -> perfect result, but notrealistic

Real-time simulation
 Grid simulation progresses, controller
thus works with “old” measurements(realistic!)
 Voltage controller set points are sent toevolved grid state (realistic!)

 Generators in the grid immediately adjust
themselves to set point Generators in grid do not immediately
adjust themselves to set points (lag) Calculation time of controller is notimportant Calculation time of controller is very
importantFrank Marten, Sebastian Wende – von Berg
© Fraunhofer IWES

Scenario (1/4)
 Generic distribution grid (110 kV)

Q-control algorithm 16 buses, 21 branches 6 loads, 3 generators (2 wind parks,1 photovoltaic park)

RESTinterface

 Time series based on weather data and standard
load profiles

Database The 3 generators can receive Q-setpoints
 ePHASORsim is used as grid simulationengine, Ts = 0.1s

IEC 61850
client

„PMU“

„RTU“
IEC 61850
server

Database
OpSim-proxy
Message Bus

Image source: Grid Layout in Pow erFactory, later converted to ePHASORsim

Frank Marten, Sebastian Wende – von Berg
© Fraunhofer IWESScenario (2/4)
Voltage controller operates every
10 seconds…

 The voltage controller receives
real-time measurements of theRMS-voltages of all network
buses(only a few sketched in picture) Using a gradient-based
optimization (from SLSQP), thecontroller decides reactive
power setpoints for the
3 generators in the grid Generator Setpoints are sent
back to the real-time simulation
via the IEC61850 interface

Frank Marten, Sebastian Wende – von Berg
© Fraunhofer IWES

Q-control algorithm

Scenario (3/4)
Generator profiles
Feed-in time series of awind park near
Dardesheim
Reference PV profile

Load profiles
Household H0
Industry G0
Agricultural L0Frank Marten, Sebastian Wende – von Berg
© Fraunhofer IWES

Scenario (4/4)
Scenarios
High/Low grid load
Voltage violations
Reactive power control
Component overloading

Component failure
Loss minimization
Adaption of power outputs(after a curtailment order isissued by TSO)
Frank Marten, Sebastian Wende – von Berg
© Fraunhofer IWES

Results (1/4)
Grid voltages without controllerFrank Marten, Sebastian Wende – von Berg
© Fraunhofer IWES

Results (2/4)
Grid voltages with controllerFrank Marten, Sebastian Wende – von Berg
© Fraunhofer IWES

Results (3/4)
Generators, following the controller‘s Q-setpoints

Frank Marten, Sebastian Wende – von Berg
© Fraunhofer IWES

Results (4/4)
Grid voltage

Frank Marten, Sebastian Wende – von Berg
© Fraunhofer IWES

Q-exchange withhigher voltage level

Generator (re)activepower output

Conclusion & discussion
 We have presented a lab environment to test a python-based grid controller(HIL-testing) Prior to HIL-testing, the controller is tested “offline”, using the OpSim

real-time simulation environment (Controller-in-the-Loop) In this “offline-test”, the controller was able to reduce the grid voltage, using
reactive power capabilities from wind parks and a large photovoltaic installation

Thank you very much for your attention!

Frank Marten, Sebastian Wende – von Berg
© Fraunhofer IWES

Contacts

Fraunhofer IWES - Department
Distribution System Operation

Dr. Frank Marten

Research groups:

 Mail: frank.marten@iwes.fraunhofer.de Phone: +49 561 7294 280

 Operation and Planning / Hybrid Grids Multi-Utility Storage Systems
 Aggregated System Operation

Dr. Sebastian Wende von-Berg
 Mail: sebastian.wendevon.berg@iwes.fraunhofer.de Phone: +49 561 7294 298
Fraunhofer IWES, OpSim, SecVer: www.iwes.fraunhofer.de www.opsim.net
 www.secver.deFrank Marten, Sebastian Wende – von Berg
© Fraunhofer IWES

Research focus: Energy and ancillary services provided
by DER (focus on PV systems,
storage systems and E-mobility) Techno-economic approaches forplanning and operation of active
distribution systems
 Energy management in decentralized
supply structures