simulating o&m with agent based and discrete event models
TRANSCRIPT
University of Stavanger
uis.no
Simulating O&M with agent based and
discrete event models
Ole-Erik Vestøl EndrerudPhD Researcher
9/22/2016
1
What we are going through
1. Problem and need in offshore wind
2. Modeling
3. Developing a framework for modeling O&M
4. Validation
5. Using O&M models for decision support
2
Problem
Existing decision support tools
are “black box”
Need for something more than
a calculator – root causes are
equally interesting
Existing methods does not
capture the behavior of
offshore wind farm O&M
5
Why Model?
The Modeled World
The Real World
The Problem The Solution
Model Model Solution
Risk-Free Space
Monte Carlo Simulation
Defined as simulations that employ random numbers, U(1,0) random variates, which is used for solving stochastic or deterministic
problems.
- Averill M. Law1
1Simulation Modeling and Analysis, 5th Ed., Averill M. Law, McGraw-Hill Education, New York, ISBN 978-0-07-340132-4
Type of Models
Deterministic models does not
contain stochastic elements
(however, the initial conditions
can be stochastic)
Stochastic models contain
stochastic elements (random
failures, random weather,
etc.)
Analytic vs Simulation Models
Can be used when:
an analytic solution exist
behavior is linear
dependencies can be described
with equations
no causal or temporal
dependencies
Can be used when:
• vast amount of parameters
• complex behavior
• temporal and causal
dependencies exist
Benefits
• You can observe the trajectory of
the system over time
• You can measure anything at any
time
Analytic Models Simulation Models
Agent-based modeling A system is modeled as several agents with
individual behavior (i.e. subsystems).
Behavior is modeled with statecharts (part of
UML).
Actions can be performed when entering, being
in or exiting a state.
Actions can also be hindered when in a state.
Transitions make agents change behavior (e.g.
from waiting on weather to moving to wind
park).
Transitions between states can be triggered by
conditions, messages or timeouts.
Process oriented modeling System model with entities
flowing through a process
Actions are executed one after one according to a flowchart
Entities are all the same, and are passive meaning the system performs some action on the entity and not vice versa
However, when entering or leaving a stage in the flowchart an action can be triggered
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Difference between statecharts and flowcharts
Statecharts perform actions in response to events (i.e. transitions) and actions can occur at transitions, when entering a state, when in a state or when exiting a state.
Flowcharts perform actions automatically upon completion of the preceding action
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State 1
State 2
State 3
Event 1
Event 2
Event 3
Event 4
Action 1
Action 2 Action 3
Action 4
Validation
18
£0m
£5m
£10m
£15m
£20m
£25m
£30m
Annual dir
ect
O&
M c
ost
s
Iain Dinwoodie, Ole-Erik V. Endrerud, Matthias Hofmann, Rebecca Martin and Iver Bakken Sperstad, 2015.
Reference Cases for Verification of Operation and Maintenance Simulation Models for Offshore Wind Farms. Wind Engineering 39(105)
Validation
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0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Tim
e-b
ase
d a
vailabilit
y
Iain Dinwoodie, Ole-Erik V. Endrerud, Matthias Hofmann, Rebecca Martin and Iver Bakken Sperstad, 2015.
Reference Cases for Verification of Operation and Maintenance Simulation Models for Offshore Wind Farms. Wind Engineering 39(105)
Using O&M models for decision support
20
Ole-Erik Vestøl Endrerud, Knut Ragnar Austreng, Nenad Keseric and Jayantha P. Liyanage, 2015. New Vessel Concepts for Operations and
Maintenance of Offshore Wind Farms. Proceedings of the Twenty-fifth (2015) International Ocean and Polar Engineering Conference
Using O&M models for decision support
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Ole-Erik Vestøl Endrerud, Nenad Keseric and Jayantha P. Liyanage, 2014. MARINE LOGISTICS DECISION SUPPORT FOR OPERATION AND
MAINTENANCE OF OFFSHORE WIND PARKS WITH A MULTI METHOD SIMULATION MODEL. Proceedings of the 2014 Winter Simulation Conference
Define decision alternatives and scenarios
Define output metrics Run n simulation runsDetermine based on
hypothesis testing the best alternative