DEGREE PROJECT IN ELECTRICAL ENGINEERING, SECOND CYCLE, 30 CREDITS STOCKHOLM, SWEDEN 2017 Time Synchronization for Ethernet Communication based Line Differential Protection SURYA SEETHARAMAN KTH ROYAL INSTITUTE OF TECHNOLOGY SCHOOL OF ELECTRICAL ENGINEERING Abstract Most of the industrial manufactures and designers of Power Substation Automation Protec- tion Control products are under pressure regarding the existing communication architecture of the Line Differential Protection Application. Currently the widely used technologies include SONET/SDH which are circuit switched networks, that are no longer predominant. They are been replaced with Packet Switched Networks everywhere. Moreover dedicated network equip- ment is required to be maintained for using SDH/SONET technologies. Hence it is becoming increasingly hard for the utilities to get access to and maintain the SDH/SONET networks. The main objective of this thesis work is to develop an alternative communication solution in order to migrate away from these SDH/SONET networks. The project work is done such that the requirements for the Line Differential Protection Communication are carefully analysed and a solution is designed such that it fulfils those requirements. Following that the imple- mentation and evaluation of the solution is performed. In the end, a testing of this solution is also done on a real-time WAN network running the Line Differential Protection function, in order to verify the working of the solution and study the challenges of a WAN deployment scenario in future. i Abstrakt De flesta industriella tillverkare och designers till produkter av system f¨orstationsautomation ¨ar under press ang˚aendeden existerande kommunikationsarkitekturen f¨orLinjedifferentialskydds- till¨ampningar. De f¨orn¨arvarande utbredda teknologierna som anv¨ands,som SONET/SDH, ¨ar kretskopplade n¨atverkvilket inte l¨angre¨arden dominerande n¨atverksprincipen. Dessa ¨arp˚av¨ag att bli ersatta av paketf¨ormedlade n¨atverk.Dessutom kr¨avsdet att dedikerad n¨atverksutrust- ning m˚aste underh˚allasf¨oratt anv¨andasmed SONET/SDH-teknologier. D¨arf¨orb¨orjar det bli kr¨avandeoch sv˚artf¨orverktygen att ges ˚atkomst samt underh˚allaSONET/SDH-n¨atverk. Huvudm˚aletmed denna uppsats ¨ar att utveckla en alternativ kommunikationsl¨osningi syfte att byta ut dessa SDH/SONET-n¨atverk.Arbetet ¨arutf¨ortgenom att f¨orstnoggrant analysera kraven f¨orLinjedifferentialskydds-kommunikation f¨oratt sedan finna och designa en l¨osning som uppfyller dessa krav. D¨arefterf¨oljeren implementation och utv¨arderingav den funna l¨osningen. I sista fasen genomf¨orsen testning av l¨osningeni ett realtids WAN-n¨atverksom k¨orLinjedifferentialskydds-funktionen, detta f¨oratt verifiera hur den funna l¨osningenfungerar samt att studera utmaningar f¨oren framtida WAN implementation. ii Acknowledgement This thesis work has been conducted in collaboration with ABB Substation Automation Prod- ucts in V¨aster˚asas well as with the Industrial Information and Control Systems department at KTH in Stockholm. This project would not have been possible without a lot of people for whom I hold a great amount of respect. Hence I would like to express my gratitude towards them and acknowledge their roles in making this thesis work happen. Johan S¨aljhas been my supervisor at ABB. He has been a pillar of great support throughout the thesis project specially when it came to technical design and guidance. Bjorn Lexelius from ABB has also been very helpful and skilled when it comes to the IED communication area. I am very thankful to both of them for sharing their broad expertise and for supervising my thesis in a systematic and dedicated manner. Moreover, it has been a great pleasure, working in the team of Henrik B¨ackstrand. In his capacity as a line manager he has helped me with all administration matters as well as with the arranging of the required technical equipment. His timely advice has always kept me motivated. Furthermore, my supervisor from KTH Fabian Hohn has been really impressive and of note- worthy help to me. During the course of my thesis work, he has always been there - giving suggestions for improvisation, clarifying doubts in case I got stuck on technical aspects, en- suring I stay on track with the project. Most importantly he has constantly encouraged me to do well right from the beginning. Professor Lars Nordstr¨omwho is head of the department of Electric Power and Energy Systems at KTH was acting as the responsible examiner of the thesis. I would like to thank him for having given me this great opportunity to conduct the thesis with ABB. Lastly, I would like to thank all my colleagues from ABB, friends from KTH and my lov- ing family in India for supporting and encouraging me throughout. iii Contents Abstract i Abstrakt ii Acknowledgement iii List of Figures viii List of Tables x Nomenclature xi 1 Introduction 1 1.1 Problem Statement . .1 1.2 Problem Description . .1 1.3 Project Goals and Scope . .2 1.4 Project Outline . .2 2 Background 4 2.1 Line Differential Protection . .4 2.1.1 Working Principle . .4 2.1.2 Requirements of the Protection Interface . .5 2.2 Existing Industrial Solutions : SDH/SONET . .5 2.3 Motivation for IP-based Ethernet Networks . .6 2.4 Time Synchronization . .7 2.4.1 Inter-Range Instrumentation Group - B . .8 2.4.2 Network Time Protocol . .8 2.4.3 SyncE . .9 2.5 Precision Time Protocol . .9 2.5.1 Protocol Details . 10 2.5.1.1 PTP devices . 10 2.5.1.2 PTP Messages . 11 2.5.1.3 PTP Communication Path . 12 iv 2.5.1.4 PTP Delay Mechanisms . 12 2.5.2 Working Principle . 17 2.5.2.1 Best Master Clock Algorithm . 18 2.5.2.2 Synchronization . 19 2.5.3 PTP Profiles . 20 2.5.3.1 PC37.238 IEEE-1588 : PTP Power Profile . 20 2.5.3.2 IEC/IEEE 61850-9-3:2016 : PTP Power Utility Profile . 21 2.5.3.3 IEEE G.8275.1/G.8275.2 : PTP Telecom Profile . 21 2.6 PTP versus existing methods . 22 3 Methodology 24 3.1 Proposed Solution . 24 3.2 Satisfying the Requirements of the Protection Interface . 24 3.3 Approach . 25 3.3.1 Communication : Packet Switched Networks . 25 3.3.2 Synchronization : Precision Time Protocol . 25 4 Implementation 26 4.1 Resources Used . 26 4.1.1 Hardware Network Components . 26 4.1.2 Software Tools . 32 4.2 Network Topologies . 35 4.2.1 N1: Point to Point Connection between two IEDs . 35 4.2.2 N2: Introducing L2 switches between the IED's . 37 4.2.3 N3: Three Ended Application - GPS to IED . 38 4.2.4 N4: Three Ended Application - GPS to switch . 39 4.2.5 N5: Hardware-in-the-Loop Trial with OMNET++ . 40 4.2.6 N6: Unlocked from GPS time reference . 41 4.3 Measurement Conditions . 42 4.3.1 Network Device Settings . 42 4.3.1.1 IED Configuration . 42 4.3.1.2 Switch Configuration . 43 4.3.1.3 GPS Clock Configuration . 43 4.3.2 Oscilloscope Settings . 43 4.3.3 Differential Current Settings . 43 5 Evaluation 44 5.1 E1: Functionality Testing . 44 5.1.1 Time Synchronization using PTP . 44 5.1.2 Line Differential Protection Communication over Ethernet . 44 5.2 E2: Performance Testing . 46 v 5.2.1 Time to Synchronize at Start-Up . 46 5.2.2 Time to Re-Synchronize . 46 5.2.3 Time synchronization Accuracy . 48 5.2.3.1 N1 : For the point to point Set-Up . 48 5.2.3.2 N2 : For introduction of L2 switches Set-Up . 49 5.2.3.3 N3 : Three-ended Application Set-Up . 50 5.2.3.4 N4 : Three-ended Application Set-Up with GPS to switch . 51 5.2.3.5 N6 : Unlocked to UTC . 52 5.3 E3: Stress Testing . 54 5.3.1 Effect on Application Communication . 56 5.3.2 Effect on PTP Communication . 57 6 Feasibility for WAN Deployment 61 6.1 WAN Description and Set-up . 61 6.2 Testing and Results . 62 6.2.1 Case 1 : With the ABB v1.2 IEDs . 63 6.2.2 Case 2 : With the ABB v2.2 IEDs . 64 6.2.2.1 Case 2.1 : Data and Sync messages over Primary route . 66 6.2.2.2 Case 2.2 : Data over Secondary and Sync over Primary routes 66 6.2.2.3 Case 2.3 : Data and Sync messages over Secondary Route . 67 6.3 Challenges during Testing . 69 6.4 Customer Requirements after the Testing . 70 6.5 General Industry Challenges for WAN Deployment . 70 7 Conclusion and Discussion 72 7.1 Conclusion . 72 7.2 Future Work . 72 Bibliography 73 Appendix 73 vi List of Figures 2.1 Line Current Differential Protection [3] . .4 2.2 PTP Clocks [16] . 11 2.3 PTP End-to-End Delay Mechanism [19] . 13 2.4 Hardware Timestamping during the transport of a Sync message [19] . 14 2.5 Working of peer-delay messages in Peer-to-Peer Delay Mechanism [20] . 15 2.6 PTP Peer-to-Peer Delay Mechanism [20] . 15 2.7 PTP Working Principle [16] . 17 2.8 PTP BMC Working . 19 4.1 RED 670 IEDs . 27 4.2 LDCM, IRIG-B and GTM Modules (left to right order) . 28 4.3 AFS 660 switch . 29 4.4 GPS clock and AFS677 switch . 29 4.5 GPS Antenna . 29 4.6 GPS clock signal relied to all network nodes in the lab . 30 4.7 Oscilloscope . 30 4.8 Communication Media . 31 4.9 Single Phase Relay Tester . 32 4.10 ABB AFS Finder 2.2.0.7 . 33 4.11 Wireshark capturing PTP sync messages . 34 4.12 Sender Application .