Operational Resilience Metrics for a Complex Electrical Networks
Alberto Tofani, Silvio Alessandroni, Gregorio D'Agostino, Antonio Di Pietro, Giacomo Onori, Maurizio Pollino and Vittorio Rosato CRITIS 2017 Lucca - ITALY, 10/10/2017
Operational Resilience Metrics
Resilienceistheabilityofthesystemtowithstandamajordisrup5onwithinacceptabledegrada5onparametersandtorecoverwithinanacceptable5meandcompositecostsandrisks.(Haimes,2009)
Theabilityofasystem,communityorsocietyexposedtohazardstoresist,absorb,accommodatetoand recover from the effects of a hazard in a 5mely and efficientmanner, including through thepreserva5onandrestora5onofitsessen5albasicstructuresandfunc5ons.[UNIDSR]
TheabilityofaCIsystemexposedtohazardstoresist,absorb,accommodatetoandrecoverfromthe effects of a hazard in a 5mely and efficientmanner, for the preserva5on and restora5on ofessen5alsocietalservices.[IMPROVERProject]*
RESILIENCE
METRICSOpera5onal Strategic
...Measuringeconomicoutputoreconomicdamagestemmingfromdisastersatana5onalorregionallevel
…howmanysparepartsareinstockandwhatop5onsexistforbackuppowergenera5on
MeasuringtheResilienceofEnergyDistribu5onSystemsbyHenryH.Willis,KathleenLoa[hYps://www.rand.org/pubs/research_reports/RR883.html]
*CIPRNetCIPedia[hYps://publicwiki-01.fraunhofer.de/CIPedia/index.php/]
Operational Resilience Metrics
QualityofService(QoS)
t
Technology
Topologyredundancy
Predic5on
Managementskills
CIsdependencies
Resourcesavailable
ResilienceR1/A
A
∝
Operational Resilience Metrics
QoS
t
Technology+
TopologyRedundancy+
Predic5on+
Managementskills
CIsdependencies
Resourcesavailable
ResilienceR’1/A’=>R’>R
A’
∝
Operational Resilience Metrics
QoS
t
Technology+
TopologyRedundancy+
Predic5on+
Managementskills-
CIsdependencies-
Resourcesavailable-
ResilienceR’’1/A’’=>R’’<R’
A’’
∝
Our proposal
Atheoryenablingtoaccountforalltheseproper5es/characteris5cswhendealingwith“resilience”es5mateshasnotbeenformulatedyet.Thisisafirsta8empttoprovideanunifyingmodelforesBmaBngtheresilienceofacoupleofdependentnetworks(electricalandtelecommunicaBon)bytakingintoaccountallofthesefactors.Ourapproach1) Buildupamodelofanelectro-telcointer-dependentsystem
enablingthesimultaneousconsidera5onofalltheseproper5esbasedonamodelrepresen5ngarealsystem
2) Defineanappropriateopera5onalmetrictoes5mateResilience3) Es5matetheResilienceofanelectricalnetworkbymeasuringthe
consequencesresul5ngfromaperturba5onconsis5nginthefaultofoneofitscomponents(i.e.aSecondarySubsta5on,SSherealer).
EDN model TheelectricalsystemisdescribedatthelevelofMVlines- PrimarySubsta5ons(PS,e.g.nodeA)andSecondarySubsta5ons(SS)
- Greynodes:tele-controlledSS- Orangenodes:automatedSS- Purplenodes:next-linesSS
- EachelementoftheEDNcanbeononeofthreefunc5onalstatus- On(Physicallyintact)- Disconnected(Physicallyintactbutfunc5onallyunavailable)- Damaged(Physicallyunavailable)
- EachSecondarySubsta5onshasassociatedanumbernofcustomers
AB C D
E
F
G H
S
L M N O
P Q R
EDN model • WemodeltheBTSallowingtele-controlfunc5onalitytoSS.EachBTSisalso
connectedtoaSSwhichensuresitselectricalsupply.
Electricaldorsalexample
1 2
3
A1 B1 C1 D1 A2B2C1
A3B3C3
A
B
C
F S
TelcoBTSElectricalSupply
Tele-control
Electrical Distribution Network outage metric
OutagemetricisexpressedasthenumberofdisconnectedcustomersofaEDNSS5mesthedura5onofitsdisconnec5on
�i =mX
j=1
nj⌧jKPIoutagemetricforadamageonnodei
Thedamageonnodeiresultsinthedisconnec5onofmnodes
SinglenodeKPIoutagemetric(kmininthefollowing)
EDN Operational Resilience Metric
• AsthevalueoftheKPIoutagemetricdependsontheResiliencefactors(e.g.networktopology,SCADAsystem,efficiencyofSCADAsystem,efficiencyofcrisismanagement,numberoftechnicalresources),itwouldnotbeinappropriatetocorrelatethevalueoftheKPIoutagemetric(Γi)withtheinverseoftheResilienceconceptR.Inotherterms
R�1 / �i
• Theoverallopera5onalnetworkResiliencewillbethusassociatedtothevalueoftheintegralofthedistribu5onfunc5onofalltheΓivalues(D(Γ))resul5ngtothefailureofeachoneoftheNnodesoftheEDN(normalizedwithrespecttothetotalnumberofnodesN):
R�1 /RD(�)d�
N
RecSIM
P
tlc t
tr t
PG t
Consequences
Γi
BTS st RecSIM
EDN
Ω m t
Network topology
SCAD
A Sy
stem
Efficiency of restoration
procedures Technical resources
Effic
ienc
y of
SCAD
A sy
stem
C
RecSIM – reconfiguration procedures
AB C D
E
F
G H
S
L M N O
P Q R
T=0SeverefailureonSSG T=0Allnodesonlinewillbedisconnected
T≈5minstheOperatoropentheswitchC-DusingtheSCADASystem
T≈180emergencycrewsinstallpowergeneratorsinnodesGandH.Nootherop5onsavailable
T≈180minsthecustomersofSSG,Harefeedtroughpowergenerators
SCENARIOA
Then,RecSIMcomputestheoutageassociatedtothescenario(KPIA)
T≈45minstheemergencyteamopentheswitchD-G.CustomersofSSDfeedaler45mins
RecSIM – reconfiguration procedures
AB C D
E
F
G H
S
L M N O
P Q R
T=0SeverefailureonSSG T=0Allnodesonlinewillbedisconnected
T≈45minstheemergencyteamopenstheswitchD-G(Faultisolated)
T≈180theemergencyteamsinstallpowergeneratorsonnodeGandH.Nootherop5onsavailable
T≈180minsthecustomersofSSG,Harefeedtroughpowergenerators
SCENARIOB
Then,RecSIMcomputestheoutagemetricassociatedtothescenario(KPIB)
KPIB>KPIA
Results: N-1 analysis
ModelparametersS1SimulaBons
Networktopology Normalconfigura5on(30-03-2017)
#oftechnicalcrews 2,4,6,8
Timefortele-controlledopera5ons 5±2mins
Timefortechnicalinterven5ononsite
45±10mins
Timeforinstallinganelectricalgenerator
180±20mins
Frac5onoftele-controlledSSbeingnottele-controllable
0.4%
Results: N-1 analysis
#oftechnicalcrews R-12 X~+2,2%
4 X(41,74)
6 X~-0,2%
8 X~-0,4%
Results: N-1 analysis
ModelparametersS2SimulaBons(lowtraffic)
Networktopology Normalconfigura5on(30-03-2017)
#oftechnicalcrews 4
Timefortele-controlledopera5ons 5±2mins
Tomefortechnicalinterven5ononsite 35±10mins
Timeforinstallinganelectricalgenerator 160±20mins
Frac5onoftele-controlledSSbeingnottele-controllable
0.4%
R-1≅X~-13%
Results: N-1 analysis
ModelparametersS3SimulaBons(hightraffic)
Networktopology Normalconfigura5on(30-03-2017)
#oftechnicalcrews 4
Timefortele-controlledopera5ons 5±2mins
Tomefortechnicalinterven5ononsite 60±10mins
Timeforinstallinganelectricalgenerator 220±20mins
Frac5onoftele-controlledSSbeingnottele-controllable
0.4%
R-1≅X~+19%
Results: N-1 analysis
ModelparametersS4SimulaBons(lowSCADAsystemavailability)
Networktopology Normalconfigura5on(30-03-2017)
#oftechnicalcrews 4
Timefortele-controlledopera5ons 5±2mins
Timefortechnicalinterven5ononsite 45±10mins
Timeforinstallinganelectricalgenerator 180±20mins
Frac5onoftele-controlledSSbeingnottele-controllable
0.8%
R-1≅X~+20%
Results N-2 analysis
ModelparametersS1SimulaBons
Networktopology Normalconfigura5on(30-03-2017)
#oftechnicalcrews 2,4,6,8
Timefortele-controlledopera5ons 5±2mins
Tomefortechnicalintervan5ononsite
45±10mins
Timeforinstallinganelectricalgenerator
180±20mins
Frac5onoftele-controlledSSbeingnottelecontrollable
0.4%
Results N-2 analysis
#oftechnicalcrews R-1
2 X~+5%
4 X(125,95)
6 X~-0,5%
8 X~-0,7%
• TheRecSimalgorithmreproducesthecascadeoffailuresfollowingthesuddenunavailabilityofone(ormore)ac5veelementsoftheelectricalgrid,itsspreadonthetelecommunica5onnetworkandthesubsequentmanagementac5vi5escarriedoutbytheoperatortorestorethegridnormalfunc5ons;
• RecSimoperatesonthewholeMVnetworkofthecityofRoma(<14.000electricalcabinsand>500telecommunica5onantennas)
Conclusions
Conclusions
• The“intrinsic”opera5onalresilience(OR)oftheMTnetworkdecreases/increasesbyvaryingthefrac5onofnotfunc5oningSCADAsystemdevicesand/orBTS(i.e.theopera5onalresiliencedecreaseofthe20%ifthenumberofnotavailabletele-controlleddevicesareduplicatedwithrespecttothenormalcondi5onse|ng);
• The~20%decreaseofthemean5meneededbyaresponseteamtoreconnectadisconnectedSS,allowsa13%ORincrease;
• The~20%increaseofthemean5meneededbyaresponseteamtoreconnectadisconnectedSSallowsa19%decrease;
Future work
• Simula5onswillbeperformedtoassesstheORvaria5onwrt
• Frac5onoftele-controlledSSinthenetwork
• Posi5onoftheswitchesalongtheMTlines
A B C D
E
F
G H
S
L M N O
P Q R
1 1
3
A1 B1 C1 D1 A2B2C1
A3B3C3
Thanks for your attention
Thisworkwasdevelopedwithin• theFP7NetworkofExcellenceCIPRNet,whichisbeingpartlyfundedbytheEuropean
CommissionundergrantnumberFP7-312450-CIPRNet.TheEuropeanCommissionssupportisgratefullyacknowledged;
• theItalianna5onalprojectRoMA(ResilienceenhancementOfaMetropolitanAreaSCN-00064).
Responsibilityfortheinforma5onandviewsexpressedhereinliesen5relywiththeauthors.Theauthorswantstofurtheracknowledgethesupportandthecontribu5onsofseveralcolleaguesduringthecourseoftheCIPRNetandRoMAprojects:ErichRomeandJingquanXie(IAIS,FraunhoferIns5tute,Bonn),LucaPellicciaandRobertoBaccini(TelecomItaliaSpA).