Use of RealTime Simulation in the CaithnessMoray HVDC

Use of Real-Time Simulation in the Caithness-Moray HVDC Transmission Project Dr. Oluwole Daniel Adeuyi 10 th April 2019 Keynote Presentation at the 4 th Nigeria Energy Forum, Lagos.

Contents q Development of HVDC in Great Britain q Drivers for Caithness-Moray (CM) HVDC Transmission Project q CM Multi-terminal HVDC Design q Use of Real-Time Simulation with HVDC Replica Controls q Summary Page: 2

Electricity Transmission in Great Britain Page: 3

Development of HVDC Links in Great Britain 2018 Interconnectors: 1) Cross Channel (IFA) 2) Moyle 3) Brit. Ned 4) EWIC 2019 2027 New Interconnector: 5) Nemo New Island Links 8) Shetland 9) Western Isles New Embedded Links: 6) Caithness – Moray 7) Western Link New Embedded Links 10) Eastern Link 1 11) Eastern Link 2 New Interconnectors 12) Elec. Link 13) NSL 14) Aquind 15) Viking 16) Green. Link 17) North. Connect 18) IFA 2 New Offshore Wind Connections 19) Dogger Bank 20) Hornsea 21) Norfolk Vanguard 4 GW Total Installed HVDC Capacity 8 GW Total Installed HVDC Capacity § The National HVDC Centre is an Ofgem-funded simulation facility available to support HVDC schemes in GB. § The Centre used real-time simulation with replica controls to support the Caithness-Moray HVDC Project. > 16 GW Installed Capacity Total HVDC Page: 4

Increasing Wind Generation in GB Background: Wind Generation: Increasing onshore wind generation capacity in North of Scotland q UK Installed Wind Capacity (MW) § Onshore: 13000 MW § Offshore: 7000 MWInstalled Wind q Scotland Capacity (MW) § Onshore: 7500 MW § Offshore: 246 MW Often in areas where electricity network is limited & weak Reason: HVDC based on voltage source converters is best technical solution Challenges: Adverse interactions (HVDC Schemes, FACTS and Generators) q North of Scotland Installed Wind Capacity (MW) § Onshore: 748 MW Multiple vendors and different technologies Multi-terminal HVDC Extension UK Installed Wind Capacity in 2017 Page: 5

Caithness-Moray (CM) HVDC Link q Phase 1 is a point-to-point HVDC link between Spittal (in Caithness) and Blackhillock (in Moray). B 0 q Key Considerations: § CM HVDC link increased B 0 boundary capability from 250 MW to 1000 MW. § HVAC option was slightly more expensive and had a number consenting issues. § Extremely Weak AC network in Spittal & Embedded HVDC with parallel HVAC circuits sets operational challenges. § Voltage source converters (VSC) technology offered black-start capability. § Symmetrical monopole configuration allows standard AC transformer use & operation during temporary faults. National Grid Electricity Ten Year Statement 2018 Configuration of Caithness-Moray HVDC Link Page: 6

Multi-Terminal HVDC Design q VSC technology was best option for 5 -terminal design with multiple offshore HVDC converter option. q VSC technology attractive due to: § 4 -quadrant PQ operation & power reversal achieved without change of voltage polarity. § Operational capability with low AC short-circuit strength than linecommutated converters. § Reduced converter size compared to other technologies. § Potential for HVDC multi-terminal extension to islanded AC networks increases project risks. 5 -terminal design for Caithness-Moray-Shetland HVDC Project Page: 7

Real-Time Simulator Meets Replica Control Measured Voltage and Current Analogue signals Firing Pulses (Digital Signal) … Replica HVDC Control Real-Time Simulator Real-time Simulator Runtime Interface • Apply network faults • Change generation dispatch • etc Operator Work Station • Start up / shut down • Change control mode • Change set points • etc Page: 8

Re-run System Tests on Extensive AC Network Simplified North of Scotland Network Modelled using RTS q Modelled North of Scotland AC Network in Real-time Simulation. q Tested response of Spittal converter station to AC faults on 275 k. V & 132 k. V circuits. q Demonstrated effectiveness of extremely weak grid control at Spittal converter station. q Validated emergency power control function for preventing voltage instability at Spittal. Page: 9

Verify HVDC Control Functions & Upgrades q Test System Status Signal North of Beauly (SSSNo. B) § Detects discontinuity on 275 k. V AC double circuit and bus bar. § Identifies low fault levels & trigger HVDC control transition to Extremely Weak Grid mode. q Test Emergency Power Control (EPC) § Detects power overload on Spittal 132 k. V AC circuits. § Initiate fast power runback/ramp-up to prevent voltage instability. Simplified Diagram showing signal transmission between RTS & Replicas Page: 10

Operator Training & Commissioning Support q Control Room Operator Training Operational Support o In-House Training o Respond to Network Changes o Diagnose Faults/Alarms o Testing Updates/ Upgrades o Long-term Model q Commissioning Support • Commissioning Support Cycle • Typical Field Measurements Page: 11

Conclusions q Real-time simulation with replica HVDC controls is used on Caithness Moray HVDC project for system testing, control verification & commissioning support. q Owners of HVDC schemes and Transmission system operators require Replica controls and real-time simulators for testing system stability, operator training & minimizing project risks. q HVDC schemes supplied by different manufacturers MUST provide replica controls for interoperability testing & de-risking future multiterminal extensions. Page: 12

Thank you! Page: 13