ENG3640 Microcomputer Interfacing Week #11 Memory Interfacing.
Interfacing Power System and ICT Simulators: Challenges, State...
Transcript of Interfacing Power System and ICT Simulators: Challenges, State...
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
Contributors:
S. C. Müller, H. Georg, J. J. Nutaro, E. Widl, Y. Deng, P. Palensky,
M. U. Awais, M. Chenine, M. Küch, H. Lin, S. Shukla, C. Wietfeld,
C. Rehtanz and M. Stifter
IEEE Power & Energy Society General Meeting 2014National Harbor, MD, USA, July 31th, 2014
IEEE Task Force on Interfacing Techniques for Simulation Tools
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
Motivation
Transition towards smart grids and cyber physical energy systems
Rise of wide-area monitoring, protection and control (WAMPAC) systems
Interaction of power system and ICT becomes more and more important,
but is often simplified in simulations
Involvement of many entities for reliable execution of applications
Communication (PMUs to PDC, inter/intra substation, controls,…)
IT data processing (decision making algorithms,…)
Latencies all along the ICT chain could be influential / critical
Impact on sequence of events, overlapping communication traffic
Impact on real-time performance of time-critical applications (e.g. wide-area protection systems)
Threat of cyber attacks
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
ICT-based WAMPAC systemsNeed for integrated analysis of power and ICT system for WAMPAC applications
• Failures in power and ICT systems can lead to critical situations in power system
operation
• mutual effects in both networks (e.g. overlapping network flows)
• real-time capability of WAMPAC applications depends on whole system behavior
• Detailed modeling of both networks is necessary for performance evaluation in order to
guarantee overall real-time requirements.
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
Focus of paper
Providing a first reference for power system engineers
outlining the challenges of a combined simulation of power and ICT systems
presenting the State of the Art of available solutions and research approaches
exemplifying the value and possibilities of an integrated simulation at the example
of test cases
Topic cannot be covered extensively on 8 pages
Bringing together a team of experienced research groups for focusing on the most
critical aspects from their perspective
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
Team
TU Dortmund University
Developers of INSPIRE co-simulator S. C. Müller, H. Georg, M. Küch, C. Rehtanz, C. Wietfeld,
Austrian Institute of Technology (AIT)
Dedicated research group on complex energy systemsand interfacing techniques
P. Palensky, E. Widl, U. Awais, M. Stifter
Virginia Tech
Developers of GECO co-simulator Y. Deng, S. Shukla, H. Lin
Oak Ridge National Laboratory
Developer of ADEVS simulator J. J. Nutaro
KTH Stockholm
Research group on real-time and hardware-in-the-loop simulation M. Chenine
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
Structure
I. Introduction
II. Modeling and Simulation Principles
Power Systems
Communication networks
Challenges of an integrated analysis of both domains
III. State of the Art: Interfacing power and ICT systems simulators
Simulation frameworks
Co-simulation approaches
Real-time and hardware-in-the-loop approaches
IV. Exemplary case studies
• Impact of cyber-attacks on PMU-based state estimation (using GECO simulator)
• Impact of ICT scenarios on power flow control application (using INSPIRE simulator)
V. Outlook and conclusion
VI. References
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
Outline
• Motivation and focus
• Team
• Modeling and simulation principles of power system and ICT simulators
• Challenges of an integrated analysis of both domains
• State-of-the-art of interfacing power and ICT systems simulators
• Simulation frameworks, co-simulation, real-time and hardware-in-the-loop simulation
• Exemplary case studies
• Impact of cyber-attacks on PMU-based state estimation (using GECO simulator)
• Impact of ICT scenarios on power flow control application (using INSPIRE simulator)
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
Modeling and simulation principles
• Excellent tools for distinct domains available
• Fundamental mathematics and numerical methods are available for simulating smart
power systems
• Difficulty lies in the cost of creating new models within new simulation frameworks for
hybrid systems
• Strong incentive to reuse existing simulation tools and models within tools
• Tradeoff as choice of picking two out of three options:
a. Reuse of communication and power system models within well-established simulation
packages
b. Accurate simulations of interactions between the two domains
c. Rapid execution of combined simulation
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
Modeling and simulation principles
• Power System Simulation
• Continous time calculations:
• System of different algebraic equations (DAEs) governed
by fundamental physical laws
• Physical coupling & dynamic interaction of many individual components and large number
of interdependent states (e.g. all synchronous machines are coupled via network
frequency and influence each other)
• DAEs solved by numerical integration methods → physical continous time processes
simulated using discrete time steps
• Communication network simulation
• Functional modeling of hardware and software processes as sequential processing
and transmission of messages and signales
• Simulations with help of discrete sequence of events in time
• Events are localized at nodes and only affect other nodes indirectly, e.g. by delay
• Often complex processes happening at software and hardware layers modeled by
statistical models with random distributions
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
Modeling and simulation principles
• Challenges of integrated analysis
• Time synchronous and deterministic execution of
• discrete event based (Communication Network)
• discrete time based (Power System)
• Object management
• Detect, link and handle related events in both domains
• Approaches for a combined analysis
• General purpose tools
• Simulation of hybrid models combining power system and
communication network domains
• Tools often lack modeling libraries, solvers and validated models
• Co-simulation
• Use specialized tools for both domains, reuse validated models
• Challenges: synchronization at runtime, lack of adequate APIs
• Hardware-in-the-loop (HIL):
• Coupling real-world hardware with a simulation tool
• Similar challenges as co-simulation, plus real time constraints
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
State of the Art:Interfacing power and ICT system simulations
• Simulation frameworks for interfacing simulators of both domains
i. High Level Architecture (HLA, IEEE 1516)
ii. Functional Mock-up Interface (FMI)
iii. Mosaik
iv. Ad-hoc
• Review of advanced co-simulation approaches
i. A Discrete EVent System simulator (ADEVS)
ii. Electrical Power and Communication Synchronizing Simulator (EPOCHS)
iii. Global Event-Driven Co-Simulation Framework (GECO)
iv. Integrated co-Simulation of Power and ICT systems for Real-time Evaluation (INSPIRE)
v. Other solutions and discussion
• Real-time and Hardware-in-the-Loop approaches
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
State of the Art:Interfacing power and ICT system simulations
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
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Control
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Exemplary case studiesCase I – Scenario Description
• Analysis of cyber-attacks on PMU-based state estimation using GECO
• Scenario:
• IEEE 39-bus 10-machine system
(New England Test System)
• Each bus 1 PMU
(reporting at 30 𝐻𝑧)
• 4 PDCs (50 𝑚𝑠 timer) and
1 Super PDC
calculating final state estimation
• Communication links in
parallel with transmission lines
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
Exemplary case studiesCase I – Simulation Results
i. Normal operation (only small random PMU measurement error)
ii. Link failure attack: communication link from bus 16 to 17 blocked at 𝑡 = 0.2𝑠
Due to new routing measurements arrive after Super PDC timer expires
System becomes unobservable
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
Exemplary case studiesCase I – Simulation Results
iii. Link saturation attack: malicious traffic injected at 𝑡 = 0.2𝑠
No immediate effect, but gradual saturation of link, from 𝑡 = 0.42𝑠 on essential
measurements have to compete with malicious traffic
State estimation still possible due to other redundant measurements
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
Exemplary case studiesCase I – Simulation Results
iv. Denial of Service (DoS) attack: depletion of the resources of a router by large amount of
redundant data or inquiries
System state switches between observable and unobservable
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
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ControlCenter
Loss oftransmission line
LastverschiebungFlexible loads
Exemplary case studiesCase II
Analysis of real-time performance of wide-area power flow control using INSPIRE
Scenario:
• Line TL0506 disconnect
after 𝑡 = 10𝑠, causing
overload of line TL0405
• “Load redispatch“ at
Substations 4 and 5
• Control Center at
Substation 39
• polling measurements
every 100𝑚𝑠
• switching loads on
demand
• 4 scenarios for the
communication network
Communication Protocol:
• IEC 61850
• Type of Messages:MMS – Type 2
• Monitoring
ACSI Service:GetDataValues
• Switching
ACSI Service:SetDataValue
• Logical Device:Bay Controller
(BBxx_BC_B1)
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
Exemplary case studiesCase II
• Scenario 1
Reference scenario,
no counteraction
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
Clearance: 0,5s
Exemplary case studiesCase II
• Scenario 2
Idle communication network
Message flow:
Measurements are
transmitted to Control
Center
Control Center detects
overload
Control Center schedules
load redispatch at
Substation 4 and 5
Effect
Synchronous
adjustments
Overload drops within
less than 0.5𝑠
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
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Exemplary case studiesCase II
• Scenario 3
• Simultaneous
line disconnect in the
communication network
• Message Flow as before
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
Exemplary case studiesCase II
• Scenario 3
• Simultaneous
line disconnect in the
communication network
• Message Flow as before
• Effects:
• Routes needs to be
updated
• Traffic flow changes
• Routing protocol causes
additional delay
• Asynchronous adjustments
• Overload drops in 1.39 𝑠resp. 1.58 𝑠 (both average)
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
Exemplary case studiesCase II
• Scenario 4
Unprioritized network traffic
Additional traffic load in the
communication network
Additional background
traffic as before
Message flow as before
Effects:
Additional delay due to
non exclusive usage of
the network
Asynchronous
adjustments
Overload drops in 1.69 𝑠resp. 1.88 𝑠 (both
average)
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
Exemplary case studiesCase II
• Scenario 5
Modeling of distributed redispatch
in distribution grid
Transmission system control
needs realized by large number
of decentralized entities
Wireless control commands
(WiMAX, TDMA (GSM))
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
Exemplary case studiesCase II
• Scenario 5
Modeling of distributed redispatch
in distribution grid
Transmission system control
needs realized by large number
of decentralized entities
Wireless control commands
(WiMAX, TDMA (GSM))
Effects:
Packet losses -> realized control
effect is smaller than command
Timely distribution of control
realizations instead of
simultaneous action
Delay dependent on wireless
technology
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
Conclusion
• Evolution of smart grids requires appropriate tools for simulating power and ICT systems
together
• Key challenges for interfacing discrete event based ICT simulators and continuous time
resp. discrete time based power system simulators
• Time synchronization
• Event handling
• Data exchange
• Various approaches available: general purpose tools, co-simulation, HIL
• Tradeoff between accuracy, execution time and ease of implementation
• Review and comparison of various state-of-the-art solutions
• Different time advance strategies, use of standardized frameworks,...
• Two case studies demonstrate capabilities of two state-of-the-art approaches as well as
necessity and value of combined simulation environments
Thank you for your Attention!
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
• Centralized Monitoring and Control Layer
Centralized components within the Power Systems
(e.g. centralized protection, control center, power plants, etc.)
Components at this layer cannot communicate directly
Within the simulator architecture, these components will be mapped to specialized
simulators
Layers of ICT-based power system operationCentralized and decentralized monitoring and control, interconnected by WAN
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
• Local Process Layer
Traffic arising within substation and field level
(e.g. local monitoring, measurements, process control, etc.)
Components at this layer can communicate directly
(e.g. using optical fibres)
Communication to other layers has to be transmitted using the
Wide-Area Communication Layer
Layers of ICT-based power system operationCentralized and decentralized monitoring and control, interconnected by WAN
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases
• Wide-Area Communication Layer
Interconnecting the other layers
Providing heterogeneous communication infrastructure (wired or wireless)
Necessity of fallback solutions
(e.g. dedicated wireless broadband, cellular networks, etc.)
Layers of ICT-based power system operationCentralized and decentralized monitoring and control, interconnected by WAN
Interfacing Power System and ICT Simulators:
Challenges, State-of-the-Art and Study Cases