Central Research Institute of Electric Power Industry
1
D2-01_24Prototype and Evaluation of
Communication Network for a WAMPAC System Based on International Standards
System Engineering Research Laboratory
2013
PS1: Role of ICT in Power SystemCIGRE SC D2 Colloquium on Smart Grid
November 14, 2013
Yoshizumi Serizawa
2
Classification of WAMPAC system
2013
1 ms 100 ms 1 s 1 min. 10 min.
Timescale of control
Areal range of influence
Narrow
Wide
Rotor anglestability(Transientstability)
Overload
Frequency stability
(Wide area)
10 ms 10 s
Rotor anglestability
Cascadesphenomena
Sampled valuePhasor
Rms value
Voltage stability(Large disturbance)
Frequencystability(Islanding)
Voltage stability(Small disturbance)
Status datafor control
3
A configuration of existing WAMPAC system
2013
Central Control Computer
Terminal Equipment
Transfer Tripping Equipment
Processed result (Generator to be shed)
System-widestate information
Sheddingcommand
G
G GG G
TE
TT
G
TETE
TE
TE
TTTT TT
TT
TT
TE
Dedicated widearea network
Legend
Starter
4
Int’l standard-based WAMPAC system
2013
CE
PMU IED
- Measurement- Status
- Measurement- Status
- Control command
- Setting
- Control sequence- Control table
- Measurement- Status
- Control sequence- Control table- Setting
WAMPAC-GW:− IEEE C37.244
(Phasor Data Concentrator)
PMU:− IEEE C37.118.1− IEC 60255-118-1
(Synchrophasor measurement)
CE – WAMPAC-GW communication:− IEC 61970 (CIM)
PDC - PMU/IED Communication :− IEC61850-90-1− IEC61850-90-5− IEEE C37.118.2
(Synchrophasor data transfer)
PMU - IED Communication :− IEC/TR 61850-90-1 (Inter-substation communication)− IEC/TR 61850-90-5 (Synchrophasor communication)
Wide area communication:− IEEE 802.1 series (Internetworking, provider backbone
bridge, etc.)− Related IETF RFCs (Routing, IP multicast, etc.)Time synchronization:− IEEE 1588 (Precision Time Protocol)− IEEE C37.238 (IEEE 1588 profile for power system)Cyber security:− IEC/TS 62351-1 to 10 (Data and communication security
for power system)− IEC/TR 61850-90-5 (Security profile for synchrophasor
communication)
WAMPAC-GW(CIM – IEC 61850)
- Control command
IED
CE: Central EquipmentCIM: Common Information ModelWAMPAC-GW: WAMPAC GatewayPMU: Phasor Measurement UnitIED: Intelligent Electronic Device
CT, VTCB status and others
CT, VT,CB status and others
CB
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Three types of WAN for WAMPAC system
2013
L3 switch/routeror MPLS router
Wide Area NetworkRSV, control table, etc.
Synchrophasor
GPS
L3 switch/routeror MPLS router
L3 switch/routeror MPLS router
L3 switch/routeror MPLS router
PMU
IED
CE
WAMPAC-GW
PMU
PMU IED
IEEE1588grand master clock
RSV, control table, scenarios, etc.RGOOSE
RGOOSE
To be excluded if GPS receivers installed in IEDs and PMUs
Wide Area Network
GPS
PMU
IED
CE
WAMPAC-GW
PMU
PMU IED
IEEE1588grand master clock
L2 switch
L2 switch
L2 switch
L2 switch
SV, control table, etc.
SynchrophasorSV, control table, scenarios, etc.
GOOSE
PTP messages
Wide Area Network
GPS
PMU
IED
CE
WAMPAC-GW
PMU
PMU IED
IEEE1588grand master clock
L2 switch
L2 switch
L2 switch
L2 switch
RSV, control table, etc.
Synchrophasor RSV, control table, scenarios, etc.GOOSE
PTP messages
L3 switch/routeror MPLS router
L3 switch/routeror MPLS router
L3 switch/routeror MPLS router
L3 switch/routeror MPLS router
L3/MPLS-based L2-based
L2/L3 combined
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Generic specifications of communication networks
2013
Function
Communication port, Bandwidth, VLAN (L2-based), Time synchronization, Communication protocol, Multicast operation for information sharing among devices, Identical bidirectional communication route , Prioritized transmission
PerformanceTransmission delay To meet the required response time, 3 to 5 ms among IEDs and PMUs, 1 s
between IED/PMU and WAMPAC-GW/CE Transmission delay variation
Less than a half of data sampling or transmission interval for ordinal data transmission. Less than 50 μs for time synchronization control channel, avoiding packet contention at normal communication ports.
Time synchronization error
Less than 50 μs for most stringent applications
Transmission error Error rate less than 1×10−6
ReliabilityUnavailability, Route assignment and redundancy, Redundancy of time synchronismCyber securitySecurity management, Availability, Integrity, Confidentiality, Key management, Access control, Network protection
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Restrictions of IEEE 1588 internetworking
2013
L2 switch network without IEEE 1588 scheme
IEEE 1588grand master
clock
L3 switch or MPLS network without IEEE 1588 scheme
IED with IEEE 1588
scheme (slave)
IED with IEEE 1588
scheme (slave)
IED with IEEE 1588
scheme (slave)
L2 switch network with IEEE 1588 scheme
PTP messages• Sync• Follow_UP• Delay_Req• Delay_Respetc.
Message delivery schemes• Unicast/multicast• Routingetc.
Combination of networks Message delivery schemes and PTP clock modesL2 with
PTP Ordinary L2 Ordinary L3 Unicast MulticastE2E-TC P2P-TC BC E2E-TC P2P-TC BC
X − − X X − − X X X − − − X X − − −
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Performance evaluation of IEEE 1588 internetworking
2013
L2 switch
L3 switch
L3 switch L3 switch
L2 switch
L2 switch L2 switch L2 switch L2 switch L2 switch L2 switch
L2 switchL2 switch
IEEE1588grand master clock
IEEE1588slave clock
IEEE1588slave clock
IEEE1588slave clock
IEEE1588slave clock
Ordinary L3 switch network
L2 switch network with IEEE 1588
L2 switch network with IEEE 1588
Connection (a)
Connection (b)
Time synchronization errors Connection (a): Tens of nanoseconds regardless of traffic congestions Connection (b): 10 and 24 μs for background traffic loads of 5 and 95% at the L3 link,
respectively, and may be much larger for longer packet traffic
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Performance evaluation of IEEE 1588 with bidirectional IP multicast and MPLS unicast
2013
L2 switch
IEEE1588grand master clock
IED/PMU(IEEE1588slave clock)
L3 switch(BIDIR-PIM)
L3 switch(BIDIR-PIM)
L3 switch(BIDIR-PIM)
L3 switch(BIDIR-PIM)
L3 switch(BIDIR-PIM)
L3 switch(BIDIR-PIM)
L2 switch
IED/PMU(IEEE1588slave clock)
L2 switch
IED/PMU(IEEE1588slave clock)
L2 switch
IED/PMU(IEEE1588slave clock)
Rendezvous point
Link failure
Time synchronization errors Bidirectional IP multicast: Temporary increase of errors by more than 30 μs (ordinary
errors of 1 to 2 μs) upon a sequence of link failure, switchover and recovery MPLS unicast: Similar to ordinary L2 switch network
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Prototype WAMPAC system
2013
CE
WAMPAC-GWIEEE1588
grand master clock
L2 switchL2 switch
L2 switch L2 switch
L3 switch
IEDPMU
IEDPMU IED PMU
IED PMU
L3 switch L3 switch
L3 switch L3 switch
Personal computer
IED/PMU
PDC
Communicationunits
AMP
Applications
RTDS
Communicationcable
Communication specificationsTransmission delay between IED and WAMPAC-GW ≤ 10 ms
Transmission delay between IEDs ≤ 10 msCommunication rate of IED and PMU
Twice per electrical cycle
Bandwidth 400 kbps per IED/PMU
Time synchronization error among IED/PMUs < 50 μs
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ConclusionsBased on the WAMPAC system architecture, the
communication network specifications in terms of function, performance, reliability and cyber security were defined.
The time synchronization characteristics were examined for L2/L3 switches with or without IEEE 1588 schemes implemented as well as multicast/unicast operations in IEDs to show a satisfactory synchronization error of a few to tens of microseconds.
A prototype WAMPAC system comprising four IEDs was established, and the operating time from fault occurrence to tripping measured less than 50 ms together with satisfactory communication and time synchronization performance.
2013
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Special reportQ1-20: What are the cases considered for evaluation of the
proposed prototype of Wide Area Monitoring, Protection and Control (WAMPAC) system based on IEEE 1588 international standard?
A1-20: While WAMPAC systems may utilize various types of WAN such as L2-based, L3/MPLS-based and L2/L3-combined networks, IEEE 1588 was originally L2-based and immature for wide area L3 networks. Therefore, the evaluations were conducted to examine the internetworking of IEEE 1588 L2 and non-IEEE 1588 L2/MPLS/L3 networks with multicast or unicast scheme in terms of time synchronization errors. The results showed the internetworked system mostly fulfilled the WAMPAC time synchronism requirement, 50 μs.
2013
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Cases for evaluationPTP master-slave time synchronism viaPTP-L2 + non-PTP- L3 network with unicast and E2E-
TCPTP-L2 network with multicast and
E2E-TC/P2P-TC/BCNon-PTP-L3/L2 network with bidirectional IP
multicastNon-PTP MPLS network with unicastwith respect to traffic congestion with/without priority
control, packet losses, network failure/recovery, and master clock switch over (BMC)
2013
142013
Reserve slides
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Another configuration of existing WAMPAC system
2013
Power plant
Substation
RPU
CPU(Central Processing Unit)
(a) Upstream information: Pre/post-fault status data, starter signal (fault detection)
(b) Downstream information (command):Generator shedding, load shedding, system separation
(a)(b)
Starter Unit
RPU
RPU (Remote Processing Unit)
CommunicationNetwork
• Microprocessor-based• Control computer-based
• Pre-calculation• Post-calculation• Disturbance detection
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Int’l standard-based WAMPAC system
2013
IEDPMU
IEC 61850/CIM converter,Phasor Data Concentrator, etc.
Power systemCT, VT, CB CT, VT, CB
Generator excitationcontrol system
- Control command
- Control sequence- Control scenarios
- Measurement- Status
- Measurement- Status
- Setting
- Measurement- Status
- Control sequence- Control scenarios- Setting
CE
WAMPAC-GW
PMU IED
Steady-state data flowData flow in the event ofthe occurrence of a fault