Unified Infrastructure-as-a-Service Platform for Distributed Co-Simulation of Networked Microgrids (IaaS Platform)

 The objective of the two short-term stays under ERIGrid 2.0 Lab Access Program is to sim
ulate a user test-case of a synthetic Low Voltage (LV) grid in the unified Infrastructure-as-a
Service (IaaS) platform through networked co-simulation and digital twins. The primary objec
tive of the conducted tests is to show a proof-of-concept of the IaaS platform for simulation
 of Cyber-Physical Power Systems (CPPSs) under constrained lab infrastructures and ease of
 development of the new models. The grid model simulated in the Digsilent PowerFactory en
vironment incorporates a digital twin simulation model of a Grid Forming Inverter (GFMI) and
 consumption from an Electric Vehicle (EV) charging station running in dedicated remote Mat
lab instances. A resistive load emulated by the RTDS system connected to an on-site power
 amplifier at the IntelligentEnergy Testbed in VTT is also connected to the modeling platform.
 The consumption of the resistive load is fed to the simulation model in real-time. The overview
 of the complete co-simulated grid model is shown in Figure 1
 The inputs and outputs of both simulated as well as real-time models are interfaced to the
 grid model by a methodology referred to as Composite Modeling in the IaaS. Composite Mod
eling requires the following necessary descriptors that are written for each component in the
 IaaS.
 1. Remote web service for communication between each simulator and the the IaaS
 2. protocol converter for communication between the each remote web service and the in
stance of the model
 Originally, 3 scenarios (Scenario 1- Scenario 3) listed in Table 1 are simulated for various
 discrete co-simulation step-sizes. The model is extended during our 2nd visit with a 5G com
munication link between the RTDS and the IaaS and 3 additional scnenarios (Scenario 4
Scenario 6) are simulated with 5G link.
 Thefollowingtargetmetricsdescribedinthecanvasdocumentareevaluatedforthesuccessful
 testingoftheIaaS.Thedescriptionoftargetmetricsisasfollows:
 1. Functionalitytestdescribedbytheconsistencyofthesimulationresultsofdigital twins.
 • Functionalitytest invalidatedfromtheresponseofdigital twinstoafrequencydis
turbanceevent generated in thesyntheticgridmodel for simulatedandreal-time
 componentsineachscenario.Thedetailsofthesimulationresultsincludingillustra
tionsaredescribedinthecompletereport.
 2.RoundTripDelay(RTD)of theIaaSdescribedbytheco-relationbetweentheelapsed
 timetelpasedandtheco-simulationtimestep∆tco−simforthesimulatedscenarios.
 • telpased isevaluatedforeachsimulationscenarioandsummarizedinTable1.
 Thefollowingkeystatementsarevalidfromtheevaluatedtargetmetrics intheproject test
case.
 • Increasingtheco-simulationstep-size(∆tco−sim)reducestheobservabilityof thesimula
tion
 • Increasingtheco-simulationstep-size(∆tco−sim)reducestheelapsedtimetelapsedof the
 simulation
 • Increasingtheco-simulationstep-size(∆tco−sim) increasesthetimedelaybetweenthe
 actual responseandobservedresponseofthedigital twinsinthesimulation.
 It isconcludedthat theco-simulationstep-size(∆tco−sim) isadesignparameterspecifictothe
 application. Thereexistsatrade-offbetweensystemobservabilityandsystemdelay. Higher
 delaysandelapsed timesaregenerallyacceptable for co-simulationsetupwithonlysimu
latedcomponentswhereas lowerdelaysarepreferredforco-simulationsetupwithreal com
ponents.
 It isalsoconcludedthat the5GLinkhasaminimaleffectontheresultsof thedigital twinsand
 theelapsedtimesoftheIaaSplatform.