Black start
A black start is the process of restoring an electric
Power to restart a generating station may come from an on-site standby generator. Alternatively, where a large amount of power is required, a tie-line to another generating plant may be used to start the facility. Once the main generating units are running, the electrical transmission network can be re-connected and electrical loads restored.
Black-start power may be ensured by an agreement where a particular energy supplier is paid to make black start power available when required. Not all generating plants are suitable for providing black-start power to a network.
Station service power
Electrical generating plants require electric power to operate systems required in the plant. For example, a coal-fuelled plant requires conveyors, crushers, air compressors, and combustion air fans to operate. Steam cycle plants require large pumps to circulate water for steam boilers and for cooling of condensate water. Hydroelectric plants require power to open intake gates, and to adjust the hydraulic turbines for speed regulation. Even a wind turbine plant may require a relatively small amount of electric power for such things as adjusting blade pitch and direction.
Normally, the electric power used within the plant is provided by the station's own generators. If all of the plant's main generators are shut down, station service power is provided by drawing power from the grid through the plant's transmission line. However, during a wide-area outage, off-site power from the grid is not available. In the absence of grid power, a so-called black start needs to be performed to bootstrap the power grid into operation.
Standby power sources
To provide a black start, some power stations have small on-site
Often
Startup sequence
One method of black start (based on a real scenario) might be as follows:
- A battery starts a small diesel generatorinstalled in a hydroelectric generating station.
- The power from the diesel generator is used to bring the generating station into operation.
- Key transmission lines between the station and other areas are energized.
- The power from the station is used to start one of the nuclear/fossil-fuel-fired base loadplants.
- The power from the base load plant is used to restart all of the other power plants in the system.
Power is finally re-applied to the general
In a larger grid, in addition to this "single island" ("bottom-up") approach, different strategies can be involved:[4][5]
- multiple islands of generation (each with local power supplying local load areas) synchronizing and reconnecting to form a complete grid. The power stations involved have to be able to accept large step changes in load as the grid is reconnected;[6]
- anchor ("core") island (also bottom-up);[7]
- "backbone island" (bottom-up): backbone is restored first, thus allowing the outside assistance;[8]
- top-down: backbone restored first with outside assistance;[9]
- a combination of top-down and bottom-up approaches.[10]
There are multiple methods of commencing a black start of an island: hydroelectric dams, diesel generators, open cycle gas turbines, grid scale battery stores, compressed air storage, and so on. Different generating networks take different approaches, dependent on factors such as cost, complexity, the availability of local resources (e.g. suitable valleys for dams), the interconnectivity with other generating networks, and the response time necessary for the black start process.
Procurement of black start services
In the United Kingdom, the grid operator has commercial agreements in place with some generators to provide black start capacity, recognizing that black start facilities are often not economical in normal grid operation.[11] It is typical of power stations from the era of the Central Electricity Generating Board to have a number of open-cycle gas turbines (i.e. no heat recovery modules attached) that can run the entirety of the plant necessary to operate a full generating unit; these would normally be started by diesel generators, fed in turn by battery backups. Once up to speed, these gas turbines are capable of running the entire plant associated with the rest of the power station, negating the need to bring power in from other sources.
In the North American
In the United States, there are currently three methods of procuring black start. The most common is cost-of-service, as it is the simplest and is the traditional method. It is currently used by the
The second method is a new method used by the Independent System Operator of New England[14] (ISO-NE). The new methodology is a flat-rate payment which increases black-start remuneration to encourage provision. The monthly compensation paid to a generator is determined by multiplying a flat rate (in $/kWyr and referred to as the $Y value) by the unit's Monthly Claimed Capability for that month. The purpose of this change was to simplify procurement and encourage provision of the black start service.
The final method of procurement is competitive procurement as used by the Electric Reliability Council of Texas[15] (ERCOT). Under this approach, ERCOT runs a market for black-start services. Interested participants submit an hourly standby cost in $/hr (e.g. $70 per hour), often termed an availability bid, that is unrelated to the capacity of the unit. Using various criteria, ERCOT evaluates these bids and the selected units are paid as bid, presuming an 85% availability. Each black-start unit must be able to demonstrate that it can start another unit in close proximity, in order to begin the islanding and synchronization of the grid.
In other jurisdictions there are differing methods of procurement. The New Zealand System Operator[16] procures the blackstart capability via competitive tender. Other jurisdictions also appear to have some sort of competitive procurement, albeit perhaps not as structured as that of ERCOT. These include the Alberta Electric System Operator,[17] as well as Independent Electric System Operator of Ontario,[18] both of which use a long-term "request for proposals" approach similar to New Zealand and ERCOT.
The first black start on Germany's grid was tested in 2017 at WEMAG battery power station in Schwerin on a disconnected, isolated grid. The WEMAG battery plant proved that it can restore the power grid after major disruption or blackout.[19]
Limitations on black start sources
Not all generating plants are suitable for black-start capability.
See also
References
- ISBN 978-0-471-49016-6section 7.5 The 'Black Start' Situation
- ISBN 0-632-06434-X, page 486
- ^ "California battery's black start capability hailed as 'major accomplishment in the energy industry'". May 17, 2017.
- ^ Gevorgian et al. 2021, p. 3.
- ^ PJM 2018, pp. 102–118.
- ^ PJM 2018, pp. 103–106.
- ^ PJM 2018, pp. 107–109.
- ^ PJM 2018, pp. 110–112.
- ^ PJM 2018, pp. 113–115.
- ^ PJM 2018, pp. 116–118.
- ^ Introduction to Black Start Archived 2006-05-21 at the Wayback Machine (National Grid plc) Covers technical and commercial background.
- ^ See PJM Tariff: Schedule 6A of the PJM Tariff, available online at: http://www.pjm.com/documents/downloads/agreements/tariff.pdf Archived 2008-12-09 at the Wayback Machine and Blackstart Business Rules, available online at: http://www.ieso.ca/Documents/consult/se16/se16_DACP-SWG-20060216-pjm-blackstart.pdf Archived 2014-12-16 at the Wayback Machine
- ^ See the NYISO Accounting and Billing Manual, 2006, available online at: http://www.nyiso.com/public/webdocs/documents/manuals/administrative/acctbillmnl.pdf Archived 2012-02-17 at the Wayback Machine
NYISO Ancillary Services Manual 2006, available at "NYISO (Documents - Manuals - Operations)". Archived from the original on 2008-09-12. Retrieved 2008-12-24.
NYISO Tariff (2006) at Rate Schedule 5, starting page 91, Revised Sheet 311, and Rate Schedule 6, starting at Revised Sheet No. 269, available online at "Archived copy" (PDF). Archived from the original (PDF) on 2008-10-12. Retrieved 2008-12-24.
{{cite web}}
: CS1 maint: archived copy as title (link) - ^ See ISO-NE "Order Accepting Application" Docket No. ER03-291, Federal Energy Regulatory Commission, Issued Feb. 14 2003, available online at http://www.iso-ne.com/committees/comm_wkgrps/trans_comm/tariff_comm/mtrls/2006/may162006/index.html ISO-NE Open Access Transmission Tariff 2006 at p. 311, available online at "ISO New England - Open Access Transmission Tariff (OATT)". Archived from the original on 2008-10-25. Retrieved 2008-12-24. ISO-NE A3 Black Start Working Group Memo to the NEPOOL Transmission Committee, May 9, 2006 available online at http://www.iso-ne.com/committees/comm_wkgrps/trans_comm/tariff_comm/mtrls/2006/may162006/index.html
- ^ See ERCOT Protocols Section 6, 2006 available online at: "ERCOT - Current Protocols". Archived from the original on 2008-11-22. Retrieved 2008-12-24. ERCOT's bidding form is available online at: http://www.ercot.com/mktrules/protocols/current/22-%28A%29BlackStart-050105.doc
- ^ Electricity Commission of New Zealand (2005-11-01). "Electricity Governance Rules, Schedule C5 - Procurement Plan" (PDF). pp. 180–182. Archived from the original (PDF) on 2006-10-07. Retrieved 2008-12-24.
- ^ See http://www.aeso.ca/files/Nov05_BlackstartPP_v1.pdf Archived 2009-03-18 at the Wayback Machine
- ^ See "Ancillary Services". Archived from the original on 2008-12-28. Retrieved 2008-12-24.
- ^ Hales, Roy L. (August 15, 2017). "First Black Start On Germany's Grid". CleanTechnica.
- ISBN 978-0-86341-449-7page 245
- ISBN 1118498038page 9-57
- ^ Reid, Scott (3 November 2020). "ScottishPower in 'pioneering world first' after wind farm black-out boost". www.scotsman.com. The Scotsman. Archived from the original on 5 November 2020.
- Scottish Power Renewables. 3 November 2020. Archivedfrom the original on 3 November 2020.
- ISBN 978-0-07-144146-9page 15-22
Sources
- Gevorgian, V.; Shah, S.; Koralewicz, P.; Wallen, R.; Mendiola, E. (March 30, 2021). "Black start from DER" (PDF). nrel.gov. NREL ESIG 2021 Spring Technical Workshop.
- PJM (2018). "Transmission ITP: System Restoration". pjm.com. PJM State & Member Training Dept.
Further reading
- 2007: Isemonger, A.G. "The Viability of the Competitive Procurement of Blackstart: Lessons from the RTOs" The Electricity Journal Volume 20, Issue 8, October 2007, Pages 60–67
- Brendan Kirby and Eric Hirst, Maintaining System Black Start In Competitive Bulk-Power Markets, American Power Conference, Chicago, Illinois, April 1999, available online at: Publications
- Lindsay Morris, Black Start: Preparedness for Any Situation, Power Engineering, Volume 115, Issue 7, July 2011, available online at: Black Start: Preparedness for Any Situation
- Rebecca Smith, Texas Grid Came Close to Bigger Disaster From Freeze, The Wall Street Journal, May 28, 2021, available online at: The Texas Grid Came Close to an Even Bigger Disaster During February Freeze