operational resilience metrics for a complex …operational resilience metrics for a complex...

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/]


QualityofService(QoS)

t

Technology

Topologyredundancy

Predic5on

Managementskills

CIsdependencies

Resourcesavailable

ResilienceR1/A

A

∝


QoS

t

Technology+

TopologyRedundancy+

Predic5on+

Managementskills

CIsdependencies

Resourcesavailable

ResilienceR’1/A’=>R’>R

A’

∝


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%


#oftechnicalcrews R-12 X~+2,2%

4 X(41,74)

6 X~-0,2%

8 X~-0,4%


ModelparametersS2SimulaBons(lowtraffic)


#oftechnicalcrews 4


Tomefortechnicalinterven5ononsite 35±10mins

Timeforinstallinganelectricalgenerator 160±20mins


0.4%

R-1≅X~-13%


ModelparametersS3SimulaBons(hightraffic)


#oftechnicalcrews 4


Tomefortechnicalinterven5ononsite 60±10mins



0.4%

R-1≅X~+19%


ModelparametersS4SimulaBons(lowSCADAsystemavailability)


#oftechnicalcrews 4


Timefortechnicalinterven5ononsite 45±10mins



0.8%

R-1≅X~+20%

Results N-2 analysis

ModelparametersS1SimulaBons


#oftechnicalcrews 2,4,6,8


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).

operational resilience metrics for a complex …operational resilience metrics for a complex...

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