Black start from generation (distributed energy resources)

The large growth in distributed energy resources (DER) presents an opportunity to develop a new approach to black-start, however, there are significant technical, organisational, and commercial challenges to address.


Components & enablers

Enablers/requirements:

  • A minimum load is required when islanding for generators to be able to start safely

    • A load bank can provide this in incremental steps
  • The anchor generator will be required to provide frequency and voltage control, which must be installed/enabled

  • A minimum fault level required for converter connected generation (e.g. wind) to connect. May not be available when operated as an island, manufacturers would have to look for alternative means.

Main issues identified for islands:

  • Low fault level
  • Low system inertia
  • Voltage control at LV (typically provided by grid transformers)
  • High variability of load and generation

State of the art in application and research

Distributed ReStart explores how Distributed Energy Resources (DER) in Great Britain can be used to restore power in the highly unlikely event of a total or partial blackout of the National Electricity Transmission System.

Participants:

  • natural gas turbines
  • biomass generators
  • embedded hydro-power stations
  • wind turbines
  • solar panels

Methods:

  1. Restarting an electricity system from a DER, or combination of DERs, from a blackout (without external power supply).
  2. Maintaining energisation of the newly created distribution Power Island of aggregated DER and blocks of demand.
  3. Expanding and synchronising with other Power Islands, energising further generation, and establishing a skeleton transmission network.

Technology Readiness Level

TRL 3

It is envisaged that the Distributed ReStart project will demonstrate a world first – coordinating a bottom up from distribution networks to transmission level to provide a safe and effective Black Start service. The project is currently starting out, with key concepts having been developed.

Technology: TRL 4-8 – research, development, demonstration and implementation:

Distributed ReStart focuses on technology that has already reached TRL 4-8 for providing black start services.

Battery + generation: TRL 7 – demonstration:

Flexitranstore demonstrates how a new, large- scale battery energy storage system connected to conventional generation can help provide black- start.


Current focus of R&D and research gaps

Distributed ReStart is currently in its early phase, but researches both technical feasibility, coordination between TSO/DSO/other agents in the event the solution will be necessary, as well as the regulatory framework.


References

[1] Distributed ReStart. [Link1] [Link2] [Link3]

[2] Flexitranstore, demo 7. [Link]