Grid Connection Issues

1
Grid Connection Issues

• Micro Hydro Projects
• Rachel Hodges

2
Where, and how suitable is the Grid?

• Tend to be in awkward locations
• Consider during initial feasibility
• Can be a go/no-go decision maker

• Look at
• Distance
• Single / 3 Phase
• Voltage
• Local Loads
• Switchgear and Ratings
• Accommodation

3
Synchronising

• Synchronous Machine
• Need inverters and controllers to match frequency
  of the grid
• Need to consider harmonic content
• Can operate in islanded system
• Asynchronous or Induction Machines
• Automatically match frequency of the grid
• Need power factor control (switchable capacitors
  or DFIG)

4
G83 versus G59

• G83

• G59

• For up to 16A per phase (6kW at Low Voltage)
• Equipment G83 Certification
• Notify the Distribution Network Operator (DNO)

• For up to 5MW at 20kV
• Connection application, connection offer and
  witness testing required.

5
Connection Application

• DNO will look at
• Transformer and connection capacity
• Abnormal feed conditions
• Fault Levels
• Voltage Rise (P28)
• Voltage Step Change, Flicker and Harmonics (G5/4)
• Loss of Mains (Islanding) Protection and Earthing
  (G59)

6
Connection Offer

• Can take up to 90 days
• Connection offer will indicate
• Non-contestable work and costs (to be undertaken
  by DNO)
• Contestable work (undertaken by accredited 3rd
  party or DNO)
• Constraints
• Timeframes

7
G59 Protection

• Under and Over Voltage
• Under and Over Frequency
• Loss of Mains (ROCOF, Vector Shift, Intertripping)

8
Metering

• ROCs
• Import / Export
• Export MPAN from Supplier
• Power Purchase Agreements
• Benefits of Onsite Generation

9
Grid Connection Issues

• Micro Hydro Projects
• Rachel Hodges