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

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

3. Electricity Transmission in Great Britain

4. Development of HVDC Links in Great Britain
2018
2019
2027
Interconnectors:
Cross Channel (IFA)
Moyle
BritNed
EWIC
New Island Links
Shetland
Western Isles
New Embedded Links
Eastern Link 1
Eastern Link 2
New Interconnectors
ElecLink
NSL
Aquind
Viking
GreenLink
NorthConnect
IFA2
New Offshore Wind Connections
Dogger Bank
Hornsea
Norfolk Vanguard
New Interconnector:
Nemo
New Embedded Links:
Caithness – Moray
Western Link
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 Total Installed HVDC Capacity

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

6. Caithness-Moray (CM) HVDC LinkB0 B0
Phase 1 is a point-to-point HVDC link between Spittal (in Caithness) and Blackhillock (in Moray).
Key Considerations:
CM HVDC link increased B0 boundary capability from 250MW to 1000MW.
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

7. Multi-Terminal HVDC Design
VSC technology was best option for 5-terminal design with multiple offshore HVDC converter option.
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 line-commutated 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

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

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

10. Verify HVDC Control Functions & Upgrades
Test System Status Signal North of Beauly (SSSNoB)
Detects discontinuity on 275kV AC double circuit and bus bar.
Identifies low fault levels & trigger HVDC control transition to Extremely Weak Grid mode.
Test Emergency Power Control (EPC)
Detects power overload on Spittal 132kV AC circuits.
Initiate fast power run- back/ramp-up to prevent voltage instability.
38 Cells at Blachillock; & 37 Cells at Spittal
EPC Target time 30 ms.
SSSNoB: ms.
Simplified Diagram showing signal transmission between RTS & Replicas

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

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

13. Thank you!