IEC TR 61850-90-12:2020

Communication networks and systems for power utility automation - Part 90-12: Wide area network engineering guidelines

IEC TR 61850-90-12:2020, which is a Technical Report, is intended for an audience familiar with electrical power automation based on IEC 61850 and related power system management, and particularly for data network engineers and system integrators. It is intended to help them to understand the technologies, configure a wide area network, define requirements, write specifications, select components, and conduct tests.
This document provides definitions, guidelines, and recommendations for the engineering of WANs, in particular for protection, control and monitoring based on IEC 61850 and related standards.
This document addresses substation-to-substation communication, substation-to-control centre, and control centre-to-control centre communication. In particular, this document addresses the most critical aspects of IEC 61850 such as protection related data transmission via GOOSE and SMVs, and the multicast transfer of large volumes of synchrophasor data.
The document addresses issues such as topology, redundancy, traffic latency and quality of service, traffic management, clock synchronization, security, and maintenance of the network.
This document contains use cases that show how utilities tackle their WAN engineering. This second edition cancels and replaces the first edition published in 2015. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
a) extension of use case with respect to distribution and customer-side applications;
b) extensions of wireless access technologies as well as power line communication ones applicable to the above-mentioned use case;
c) revisions regarding radio communication technology performance;
d) extension of network migration with respect to packet switched network;
e) a new mapping of multiprotocol label switching technology to teleprotection.

General Information

• Status: Published
• Publication Date: 27-Jul-2020
• ICS: 33.200 - Telecontrol. Telemetering
• Technical Committee: TC 57 - Power systems management and associated information exchange
• Drafting Committee: WG 10 - TC 57/WG 10
• Current Stage: PPUB - Publication issued
• Start Date: 28-Jul-2020
• Completion Date: 18-Aug-2020

Relations

• Revises: IEC TR 61850-90-12:2015 - Communication networks and systems for power utility automation - Part 90-12: Wide area network engineering guidelines
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC TR 61850-90-12 ®
Edition 2.0 2020-07
TECHNICAL
REPORT
colour
inside
Communication networks and systems for power utility automation –
Part 90-12: Wide area network engineering guidelines
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IEC TR 61850-90-12 ®
Edition 2.0 2020-07
TECHNICAL
REPORT
colour
inside
Communication networks and systems for power utility automation –

Part 90-12: Wide area network engineering guidelines

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.200 ISBN 978-2-8322-8657-9

– 2 – IEC TR 61850-90-12:2020 © IEC 2020
CONTENTS
FOREWORD . 12
INTRODUCTION . 14
1 Scope . 16
2 Normative references . 16
3 Terms, definitions, abbreviated terms, acronyms, and symbols . 21
3.1 Terms and definitions . 21
3.2 Abbreviated terms and acronyms . 25
3.3 Network diagram symbols . 34
4 Wide area communication in electrical utilities . 36
4.1 Executive summary . 36
4.2 Network and application example: ENDESA, Andalusia (Spain) . 38
4.3 Typical interface between a substation and the WAN . 40
4.4 WAN characteristics and actors . 41
4.5 Smart Grid Architecture Model (SGAM) Mapping . 42
4.6 Network elements and voltage level . 44
4.7 WAN interfaces in substation automation (IEC 61850-5) . 45
4.8 Logical interfaces and protocols in the architecture in IEC TR 62357-200 . 46
4.9 Network traffic and ownership . 47
5 WAN metrics . 48
5.1 Traffic types . 48
5.2 Quality of Service (QoS) of TDM and PSN . 48
5.3 Latency calculation . 48
5.3.1 Latency components . 48
5.3.2 Propagation delay . 49
5.3.3 Residence delay . 49
5.3.4 Latency accumulation . 49
5.3.5 Example: latency of a microwave system . 49
5.3.6 Latency and determinism . 50
5.3.7 Latency classes in IEC 61850-5 . 50
5.4 Jitter . 52
5.4.1 Jitter definition . 52
5.4.2 Jitter classes in IEC 61850 . 53
5.5 Latency symmetry and path congruency . 53
5.6 Medium asymmetry . 53
5.7 Communication speed symmetry . 54
5.8 Recovery delay . 54
5.9 Time accuracy . 54
5.9.1 Time accuracy definition . 54
5.9.2 Time accuracy classes. 55
5.10 Tolerance against failures . 56
5.10.1 Failure . 56
5.10.2 Reliability. 57
5.10.3 Redundancy principles. 57
5.10.4 Redundancy and reliability . 58
5.10.5 Redundancy checking . 59
5.10.6 Redundant layout: single point of failure . 59

5.10.7 Redundant layout: cross-redundancy . 60
5.10.8 Maintainability . 61
5.10.9 Availability . 61
5.10.10 Integrity . 63
5.10.11 Dependability . 64
5.10.12 Example: Dependability of GOOSE transmission . 64
6 Use cases and WAN communication requirements . 65
6.1 List of generic use cases . 65
6.2 Teleprotection (IF2 & IF11) . 66
6.2.1 Teleprotection schemes . 66
6.2.2 Teleprotection data kinds . 66
6.2.3 Current differential teleprotection for multi-terminal transmission line . 66
6.2.4 Teleprotection communication requirements . 67
6.3 Wide area monitoring system (IF13) . 69
6.3.1 WAMS overview . 69
6.3.2 WAMS topology . 70
6.3.3 WAMS communication requirements . 72
6.4 Wide area monitoring, protection, and control (WAMPAC) IF13 . 74
6.4.1 Functional description . 74
6.4.2 WAMPAC communication requirements . 76
6.5 Fault Location . 76
6.5.1 Functional description . 76
6.5.2 Fault location communication requirements . 78
6.6 Distribution Automation . 78
6.6.1 Functional description . 78
6.6.2 Distribution automation communication requirements . 79
6.7 Condition monitoring and diagnostics (CMD) and asset management (IF7) . 80
6.7.1 Functional description . 80
6.7.2 CMD communication requirements . 80
6.8 Telecontrol (SCADA) . 81
6.8.1 Functional description . 81
6.8.2 Telecontrol communication requirements . 81
6.9 Control centre to control centre (IF12) . 82
6.9.1 Functional description . 82
6.9.2 Inter control centre communication requirements . 83
6.10 Smart metering / advanced metering infrastructure . 84
6.10.1 Functional description . 84
6.10.2 Smart metering communication requirements . 84
6.11 WAN communication requirements summary . 85
7 Wide-area and real-time network technologies. 86
7.1 General . 86
7.2 Topology . 86
7.3 Overview. 87
7.4 Layer 1 (physical) transmission media . 89
7.4.1 Summary . 89
7.4.2 Installation guidelines . 89
7.4.3 Metallic lines . 89
7.4.4 Power line carrier (PLC) . 91
7.4.5 Radio transmission . 101

– 4 – IEC TR 61850-90-12:2020 © IEC 2020
7.4.6 Fibre optics. 112
7.4.7 Layer 1 redundancy . 118
7.4.8 Application example: diverse redundancy against extreme
contingencies (Hydro-Quebec) . 119
7.4.9 Layer 1 security . 120
7.5 Layer 1,5 (physical) multiplexing . 120
7.6 Layer 2 (link) technologies . 121
7.6.1 Telephony technologies . 121
7.6.2 SDH/SONET . 123
7.6.3 Optical Transport Network . 133
7.6.4 Ethernet . 135
7.6.5 Ethernet over TDM . 144
7.6.6 Carrier Ethernet . 146
7.6.7 Audio-video bridging . 147
7.6.8 Provider Backbone Bridge (PBB) . 147
7.6.9 Multiprotocol Label Switching (MPLS) . 149
7.7 Layer 3 (network) technologies . 157
7.7.1 Internet Protocol (IP) . 157
7.7.2 IP QoS. 167
7.7.3 IP multicast. 170
7.7.4 IP redundancy . 171
7.7.5 IP security . 171
7.7.6 IP communication for utilities . 173
7.7.7 IP summary . 175
7.8 Layer 4 (transport) protocols . 176
7.8.1 Transport layer encapsulation . 176
7.8.2 UDP . 176
7.8.3 TCP . 177
7.8.4 Layer 4 redundancy . 178
7.8.5 Layer 4 security . 178
7.9 Layer 5 (session) and higher . 178
7.9.1 Session layer . 178
7.9.2 Routable GOOSE and SMV . 179
7.9.3 Example: C37.118 transmission . 179
7.9.4 Session protocol for voice and video transmission . 180
7.9.5 Application interface redundancy . 180
7.9.6 Application device redundancy . 181
7.10 Protocol overlay – tunnelling . 181
7.10.1 Definitions . 181
7.10.2 Tunnelling principle . 182
7.10.3 Tunnelling Layer 2 over Layer 3 . 182
7.10.4 Application Example: Tunnelling GOOSE and SMV in IEC 61850 . 183
7.11 Virtual private networks (VPNs) . 184
7.11.1 VPN principles . 184
7.11.2 L2VPNs . 184
7.11.3 L2VPN multicast on MPLS . 186
7.11.4 L3VPN . 186
7.11.5 VPN mapping to application . 188
7.12 Cyber security . 192

7.12.1 Security circles . 192
7.12.2 Network security . 193
7.12.3 Access control . 195
7.12.4 Threat detection and mitigation. . 195
7.12.5 Security architecture . 199
7.12.6 Application (end-to-end) communication security . 200
7.12.7 Security for synchrophasor (PMU) networks (IEC TR 61850-90-5) . 201
7.12.8 Additional recommendations . 202
7.13 QoS and application-specific engineering. 202
7.13.1 General . 202
7.13.2 SDH/SONET QoS and SLA . 202
7.13.3 PSN QoS and SLA . 202
7.13.4 Application and priority . 203
7.13.5 QoS chain between networks . 203
7.13.6 QoS mapping between networks . 204
7.13.7 QoS engineering . 205
7.13.8 Customer restrictions . 206
7.13.9 Clock services . 206
7.14 Configuration and OAM . 206
7.14.1 Network configuration . 206
7.14.2 OAM . 206
7.15 Time synchronization . 208
7.15.1 Oscillator stability . 208
7.15.2 Mutual synchronization . 209
7.15.3 Direct synchronization . 209
7.15.4 Radio synchronization . 210
7.15.5 GNSS synchronization . 210
7.15.6 Frequency distribution . 210
7.15.7 Time distribution . 212
7.15.8 PTP telecommunication profiles . 218
7.15.9 PTP over MPLS . 219
7.15.10 Comparison of time distribution profiles based on IEC 61588 . 219
7.15.11 Application example: synchrophasor time synchronization . 220
7.15.12 Application example: Atomic clock hierarchy . 221
8 Technology mapping to applications . 222
8.1 Overview. 222
8.2 Current differential teleprotection for multi-terminal transmission lines . 222
8.2.1 General . 222
8.2.2 Deterministic fibre-optic PDH loop network . 223
8.2.3 Dedicated Gigabit Ethernet network . 223
8.2.4 Carrier Ethernet with wide-area time synchronization. 224
8.2.5 MPLS based wide area network . 225
8.3 Wide area monitoring, protection, and control (WAMPAC) . 227
8.3.1 General . 227
8.3.2 Wide area stabilizing control using legacy network . 227
8.3.3 PMU-based WAMPAC using time-synchronized Layer 2 and Layer 3
network. 229
8.4 Fault location . 231
8.5 SCADA and facility maintenance . 232

– 6 – IEC TR 61850-90-12:2020 © IEC 2020
8.6 Distribution automation . 234
8.7 Smart metering . 234
9 Network migration . 237
9.1 TDM to packet switched network . 237
9.1.1 General . 237
9.1.2 Overview . 237
9.1.3 Drivers for network migration . 237
9.1.4 Considerations for network migration . 238
9.1.5 Migration concepts . 240
9.1.6 Implementation details . 246
9.2 From IPv4 to IPv6 . 250
9.2.1 IPv4 to IPv6 evolution . 250
9.2.2 IPv4 to IPv6 migration . 250
9.2.3 IEC 61850 stack with IPv4 and IPv6 . 251
Annex A (informative) Future promising or upcoming technologies . 252
A.1 5G . 252
A.1.1 General . 252
A.1.2 Different performance requirements . 253
A.2 Deterministic networking technologies . 256
Bibliography . 257

Figure 1 – Symbols . 35
Figure 2 – Substation locations in Andalusia . 38
Figure 3 – Topology of the Andalusia network . 39
Figure 4 – Cabinet of a substation edge node . 40
Figure 5 – Communication interfaces in a SEN . 41
Figure 6 – Communicating entities . 42
Figure 7 – SGAM communication model. 43
Figure 8 – Principle of grid voltage level and network technology . 44
Figure 9 – Communication paths and interfaces . 45
Figure 10 – IEC TR 62357 Interfaces, protocols, and applications. 46
Figure 11 – Composition of end-to-end latency in a microwave relay . 49
Figure 12 – Example of latency in function of traffic . 50
Figure 13 – Jitter for two communication delay types . 52
Figure 14 – Precision and accuracy definitions . 55
Figure 15 – Redundancy of redundant systems . 58
Figure 16 – Redundancy calculation . 59
Figure 17 – Redundancy layout with single point of failure . 59
Figure 18 – Redundancy layout with cross-coupling . 60
Figure 19 – Availability definitions . 61
Figure 20 – Residual error rate as a function of BER . 63
Figure 21 – Network configurations for multi-terminal line protection . 67
Figure 22 – Principle of synchrophasor transmission . 71
Figure 23 – PMUs and data flow between TSO and regional data hubs . 72
Figure 24 – Target phenomena for WAMPAC . 74

Figure 25 – Example of main function and general information flow . 75
Figure 26 – Network configuration for a fault locator system . 77
Figure 27 – System configuration for distribution automation . 79
Figure 28 – Network configurations for CMD and asset management . 80
Figure 29 – Logical network configuration for telecontrol (SCADA) . 81
Figure 30 – Network configurations for inter-control centre . 83
Figure 31 – System configuration for smart metering . 84
Figure 32 – Network ring topology example . 87
Figure 33 – Narrowband channel plans for LV PLC Europe vs. North America . 93
Figure 34 – HF allocated frequency spectrum plans for LV BPL . 93
Figure 35 – Narrowband spectrum usage vs. standards and regulation areas [57] . 94
Figure 36 – HV PLC link building blocks. 96
Figure 37 – Phase-to-ground coupling for PLC . 97
Figure 38 – HV PLC coupling with suspended line traps . 97
Figure 39 – Phase-to-phase signal coupling for PLC . 98
Figure 40 – Phase-to-phase signal coupling . 98
Figure 41 – Power line carrier, line traps . 99
Figure 42 – Terrestrial microwave link . 102
Figure 43 – Layer 2 transport on microwave radio systems . 103
Figure 44 – DMR (Digital Mobile Radio) . 106
TM
Figure 45 – LoRaWAN Protocol Stack . 108
Figure 46 – ADSS fibre cable . 113
Figure 47 – ADSS installation with splicing box . 113
Figure 48 – OPGW in ground cable . 114
Figure 49 – OPGW with two "C"-tubes each with 32 fibers . 114
Figure 50 – OPGW fibers . 115
Figure 51 – Splicing box . 116
Figure 52 – WDM over one fibre . 117
Figure 53 – OCh optical components . 117
Figure 54 – Optical link with microwave back-up . 119
Figure 55 – Photograph of a partially destroyed 735 kV line . 120
Figure 56 – E1 and E2 channels . 122
Figure 57 – Digital transmission hierarchy (T-standards) . 122
Figure 58 – Digital transmission hierarchy (E-standard) . 123
Figure 59 – Example of an SDH network for utilities . 124
Figure 60– SONET multiplexing hierarchy . 125
Figure 61 – SDH multiplexing hierarchy . 125
Figure 62 – SDH/SONET with point-to-point topology . 127
Figure 63 – SDH/SONET with linear topology . 127
Figure 64 – BLSR/BSHR topology in normal conditions (from A to D) . 129
Figure 65 – BLSR/BSHR topology in failure conditions . 129
Figure 66 – SNCP/UPSR topology in normal conditions . 130
Figure 67 – SNCP/UPSR topology in failure conditions . 131

– 8 – IEC TR 61850-90-12:2020 © IEC 2020
Figure 68 – Example of information flow relationship in OTN . 134
Figure 69 – IEEE 802.3 (Ethernet) frame format . 135
Figure 70 – IEEE 802.3 (Ethernet) topology with RSTP switches . 136
Figure 71 – IEEE 802.1Q-tagged Ethernet frame format . 137
Figure 72 – Direct Ethernet with VLAN in substation-to-substation transmission . 138
Figure 73 – Substation-to-substation Layer 2 transmission tunnelled over IP . 139
Figure 74 – PRP structure (within and outside a substation) . 140
Figure 75 – HSR ring connecting substations and control centre . 141
Figure 76 – MACsec frame format . 142
Figure 77 – IEEE 802.1X principle . 143
Figure 78 – Ethernet for substation-to-substation communication. 144
Figure 79 – Packets over TDM . 145
Figure 80 – IEEE 802.1Q/ad/ah network configuration . 148
Figure 81 – Basic MPLS architecture . 150
Figure 82 – Example of MPLS frame format with IPv4 payload . 150
Figure 83 – MPLS building blocks . 151
Figure 84 – MPLS network architecture for utilities . 153
Figure 85 – IP/MPLS and MPLS-TP features . 154
Figure 86 – MPLS-TP redundant routing . 156
Figure 87 – Ethernet frame with IP network header . 157
Figure 88 – Mapping of IPv4 to Ethernet frames . 158
Figure 89 – Mapping of IPv6 to Ethernet frames . 161
Figure 90 – IPv6 unicast address structure . 162
Figure 91 – IPv6 ULA address structure . 163
Figure 92 – IPv6 link local address structure . 163
Figure 93 – Mapping of IPv4 to IPv6 addresses . 166
Figure 94 – DiffServ codepoint field . 169
Figure 95 – Unidirectional protocol independent multicast . 170
Figure 96 – Bidirectional protocol independent multicast . 171
Figure 97 – Frame format for IPsec (authenticated) . 172
Figure 98 – Frame format for IPsec (encrypted) . 172
Figure 99 – Layer 3 direct connection within same address space . 173
Figure 100 – Connecting substations to SCADA by a NAT . 174
Figure 101 – Substation to SCADA connection over ALG . 175
Figure 102 – Ethernet frame with UDP transport layer . 176
Figure 103 – UDP header . 177
Figure 104 – TCP header . 177
Figure 105 – Session and presentation layers for MMS . 179
Figure 106 – Session and presentation layers for R-GOOSE . 179
Figure 107 – IEEE C37.118 frame over UDP . 180
Figure 108 – Redundant network transmission handled by the application layer . 180
Figure 109 – Tunnelling in IEC TR 61850-90-1 . 182
Figure 110 – L2TP transporting Layer 2 frames over IP . 183

Figure 111 – Tunneling SMV over IP in IEC TR 61850-90-5 . 184
Figure 112 – L2VPNs VPWS and VPLS . 185
Figure 113 – L3VPN . 186
Figure 114 – Emulation of L3VPN by L2VPN and global router . 188
Figure 115 – Tele-protection over VPWS . 190
Figure 116 – WAMS over VPLS . 190
Figure 117 – VPN for IP-based SCADA/EMS traffic . 191
Figure 118 – VPN deployment options . 194
Figure 119 – IP network separator . 196
Figure 120 – Security architecture (using segmentation and perimeter security) . 200
Figure 121 – QoS chain . 204
Figure 122 – Timing pulse transmission methods of legacy teleprotection devices . 209
Figure 123 – SyncE application . 211
Figure 124 – Synchronous Ethernet architecture . 211
Figure 125 – SNTP clock synchronization and network delay measurement . 213
Figure 126 – Model of GMC, two BCs in series and SC over Layer 3 . 216
Figure 127 – Timing diagram of PTP (end-to-end, 2-step, TC and BC) . 216
Figure 128 – Timing diagram of PTP (peer-to-peer, 2-step TCs) . 217
Figure 129 – Substations synchronization over WAN . 221
Figure 130 – Example of synchronization network . 222
Figure 131 – Distributed loop configuration for HV multi-terminal line protection . 223
Figure 132 – Current differential teleprotection for HV multi-terminal transmission line
using Layer 2 network . 224
Figure 133 – Configuration of wide area current differential primary and backup
teleprotection system employing Carrier Ethernet and IEC 61588 time synchronization . 225
Figure 134 – Current differential protection communication via MPLS network . 226
Figure 135 – System configuration for wide area stabilizing control system . 228
Figure 136 – Appearance of typical CCE cubicle . 228
Figure 138 – IEEE 802.1Q/ad utility network . 232
Figure 139 – Mixed SDH/MPLS network for SCADA and facility maintenance services . 233
Figure 140 – Wi
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