the integration of renewable energy onto the existing grid dr norman macleod technical director,...
TRANSCRIPT
The Integration of Renewable Energy onto the Existing Grid
Dr Norman MacLeod
Technical Director, HVDC
Run of the river schemes use the natural force of the water to turn the turbines
• Minimal environmental impact
Dams create a head of water which turns the turbines
• Significant environmental impact
Micro-hydro generation
• Diverting water from local streams
• Connected to the local community
Hydro-electric Power
On-shore
• wind farms are typically 10 – 50MW
• Turbines typically up to 3MW rating
• Connected at distribution voltage level
Wind Power
Off-shore
• wind farms are typically up to 600MW (AC connected) and 1200MW (DC connected)
• Turbines up to 8MW
• Connected at transmission voltage level
Domestic
• Connected to the low voltage distribution grid
• Supplies local loads and any excess is fed into the distribution grid
Commercial
• Photovoltaic panels generate electricity at low voltage DC
• Conversion from DC to AC is needed for connection to the transmission grid
Solar Power
Other sources• Wave power – in development• Tidal power – barrage schemes in use • Tidal power – submerged turbines in development• Bio-mass – in use as a coal replacement• Electric vehicles – both a load and a generator
Renewable Energy Sources
• Intermittency of power generation• Remoteness of power sources from load centres• Impacts on system stability - • Loss of inertia on the network – closure of rotating plant• Harmonic distortion – Irish Grid Code• Low voltage ride-through – Irish grid Code
The Issues
• Diversity of power sources• Fossil fuels + renewables
• Grid enhancement• AC transmission lines and/or HVDC embedded links
• HVDC interconnectors to neighbouring grids (UK, France)• Dynamic reactive power devices
• SVC or STATCOM
• Harmonic filters• Passive and/or active
• Advanced power electronic controllers• “Synthetic inertia”
• Storage systems
The Solutions
Off-shore Wind Farm (AC)Source : Alstom
Wind Turbines
AC Collector Platform
On-shore sub-station
Submarine cable
STATCOMSource : Siemens
Greater Gabbard off-shore wind farm, UK
• Control of reactive power flow• Low voltage ride through• Harmonic distortion• System stability
HVDC Transmission
DC transmissionline
Q1 Q2P
VSC VSC
Station 1 Station 2
UC1 UC2
IC1
Network1
Network2
t
i
Iact
i
Iact
Idci
East West Interconnector (EWIC)Source : EirGrid
AC
DC
AC
DC
AC S/S
AC S/S
Woodland Converter Station
Shotton Converter Station
45km 181km 34km
Eirgrid National Grid
±200kV XLPE Cables
Woodland Converter StationSource : EirGrid
Exterior view of converter station Interior view – converter hall
Ireland HVDC Schemes
Existing Interconnectors
Future interconnectors
Embedded links
The Existing AC Grid
ACAC
110 kV 110 kV
400 V 400 V
10 kV
400 kV
400 V
10 kV
10 kV
AC
AC
AC
AC
AC
AC
AC
AC
AC
AC
AC
AC
AC
AC
AC
AC
The Grid of the Future?
ACAC
DCDC
110 kV 110 kV
400 V 400 V
10 kV
400 kV
400 V
10 kV
35 kV
Offshore wind farm
150 kV 150 kV 150 kV150 kV
Bulk power import using HVDC
320 kV
ACDC
DC
DC
AC
DC
AC
DC
50 kV 50 kV
DC
DC
DC
DC
AC
AC
AC
AC
AC
AC
AC
AC
AC
AC
AC
AC
AC
AC
AC
DC
DC
DC
DC
DC
DC
DC
DC
DC500 V
Electric VehicleCharging Stationstation
AC
DC
AC
AC
10 kV 10 kV
AC
DC
AC
AC
500 V
BatteryEnergyStorageSystem
Photo Voltaic
DC
DC
Power Cells
• High levels of renewable generation can result in significant issues on the existing AC network
• Smart grid solutions can be used to support and manage integration of renewable energy sources
• Smart Grids = Power Electronics + Automation Systems
Conclusions
Any questions?
Tormoid Mhic Leòid