Econnect Ltd
Independent specialists in
the grid integration of
renewable energy...
Grid Connections: Lessons
from Round One
Paul Glendinning
Operations Manager
Econnect Offshore
Credentials
• Designed 7 offshore wind farms
• Research for the DTI – Medium Voltage
Systems for Offshore Windfarms
• Electrical Construction Management at
North Hoyle
Introduction
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•
•
•
•
Onshore work for Offshore Projects
Differences ?
What are the issues ?
Solutions
Conclusions
Onshore work for Offshore
Projects
• Substation connections
• Either at 132kV or 33kV for the 30 to 60
turbine wind farms
• Cable connections
• Onshore Cable interconnection facility
North Hoyle Progress
• Onshore works
• Offshore /
Onshore
Interface
North Hoyle Progress
• Onshore works
• Cable
Installation
through the
streets
North Hoyle Progress
• Onshore Works
• Careful
management in
public areas
North Hoyle Progress
• Onshore works
• Protection of
cables in road
North Hoyle Progress
• Onshore works
• Careful route
selection around
a playing field
Differences ?
•
•
•
•
Electrical connection arrangements
Radial versus Interconnected systems
Cost of repairs – mobilisation of vessels
Shore link cable environment
Differences ?
• Repair and
fault finding
Crew ?
What are the issues ?
• Switching, protection and Isolation
• Subsea cable fault repair
• Failure minimisation – maximise
revenue
• Electrical losses
Solutions - Switching,
Protection and Isolation
• Increasing degrees of automation
required
• Use of motorised ring switches
• Use of Fault Passage Indicators
• Reduce visits to farm
• Avoid personnel transfer to turbines
Solutions - Switching,
Protection and Isolation
Wind Turbine 1
Wind Turbine 2
FPI
Wind Turbine 3
FPI
Wind Turbine 4
FPI
FPI
Grid Connection
Cable Fault
Fault Current
Fault Current
Wind Turbine 5
Solutions Subsea cable fault repair
• Use of Time Domain Reflectometers or
search coil
• Cable on shore link may be tens of
meters away from original burial
position
• Burial methods require careful analysis
Solutions - Failure
minimisation
• Cost of single cable fault in 60 MW wind
farm is £650K
• Use of standby power from Offshore
diesel equipment
• Use of interconnected electrical
systems
Solutions - Failure
minimisation
• Layout at North
Hoyle
Solutions - environment
• Equipment utilised must have a
marinised specification
• Shore link cable requires careful
analysis of burial depth and protection
requirements – Geotechnical data
required.
Conclusions
• Onshore electrical arrangements –
not valid
• The protection of the shore link cable is
critical compared to inter-link cables
• Equipment utilised must be marinised
• Invest in cable specification and
installation protection
• Invest in Electrical topology
Econnect Ltd
Independent specialists in
the grid integration of
renewable energy...