Definition: Blackstart Capability Plan

From Open Energy Information

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Blackstart Capability Plan

A documented procedure for a generating unit or station to go from a shutdown condition to an operating condition delivering electric power without assistance from the electric system. This procedure is only a portion of an overall system restoration plan.[1]

Wikipedia Definition

A black start is the process of restoring an electric power station or a part of an electric grid to operation without relying on the external electric power transmission network to recover from a total or partial shutdown. 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. To provide a black start, some power stations have small diesel generators, normally called the black start diesel generator (BSDG), which can be used to start larger generators (of several megawatts capacity), which in turn can be used to start the main power station generators. Generating plants using steam turbines require station service power of up to 10% of their capacity for boiler feedwater pumps, boiler forced-draft combustion air blowers, and for fuel preparation. It is uneconomical to provide such a large standby capacity at each station, so black-start power must be provided over designated tie lines from another station. Often hydroelectric power plants are designated as the black-start sources to restore network interconnections. A hydroelectric station needs very little initial power for starting purposes (just enough to open the intake gates and provide excitation current to the generator field coils) and can put a large block of power on line very quickly to allow start-up of fossil-fuel or nuclear stations. Certain types of combustion turbine can be configured for a black start, providing another option in places without suitable hydroelectric plants. In 2017, a utility in Southern California successfully demonstrated the use of a battery-based energy-storage system to provide a black start, firing up a combined-cycle gas turbine from an idle state. One method of black start (based on a real scenario) might be as follows: 1.
  • A battery starts a small diesel generator installed in a hydroelectric generating station. 2.
  • The power from the diesel generator is used to bring the generating station into operation. 3.
  • Key transmission lines between the station and other areas are energized. 4.
  • The power from the station is used to start one of the nuclear/fossil-fuel-fired base load plants. 5.
  • 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 electricity distribution network and sent to the consumers. Often this will happen gradually; starting the entire grid at once may be unfeasible. In particular, after a lengthy outage during summer, all buildings will be warm, and if the power were restored at once, the demand from air conditioning units alone would be more than the grid could supply. In colder climates, a similar issue can occur in winter with the use of heating devices. In a larger grid, the black start will often involve starting multiple "islands" of generation (each supplying local load areas), and then synchronizing and reconnecting these islands 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. There are multiple methods of commencing a black start: 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 (i.e. suitable valleys for dams), the interconnectivity with other generating networks, and the response time necessary for the black start process., A black start is the process of restoring an electric power station or a part of an electric grid to operation without relying on the external electric power transmission network to recover from a total or partial shutdown. 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. To provide a black start, some power stations have small diesel generators, normally called the black start diesel generator (BSDG), which can be used to start larger generators (of several megawatts capacity), which in turn can be used to start the main power station generators. Generating plants using steam turbines require station service power of up to 10% of their capacity for boiler feedwater pumps, boiler forced-draft combustion air blowers, and for fuel preparation. It is uneconomical to provide such a large standby capacity at each station, so black-start power must be provided over designated tie lines from another station. Often hydroelectric power plants are designated as the black-start sources to restore network interconnections. A hydroelectric station needs very little initial power for starting purposes (just enough to open the intake gates and provide excitation current to the generator field coils) and can put a large block of power on line very quickly to allow start-up of fossil-fuel or nuclear stations. Certain types of combustion turbine can be configured for a black start, providing another option in places without suitable hydroelectric plants. In 2017, a utility in Southern California successfully demonstrated the use of a battery-based energy-storage system to provide a black start, firing up a combined-cycle gas turbine from an idle state. One method of black start (based on a real scenario) might be as follows: 1.
  • A battery starts a small diesel generator installed in a hydroelectric generating station. 2.
  • The power from the diesel generator is used to bring the generating station into operation. 3.
  • Key transmission lines between the station and other areas are energized. 4.
  • The power from the station is used to start one of the nuclear/fossil-fuel-fired base load plants. 5.
  • 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 electricity distribution network and sent to the consumers. Often this will happen gradually; starting the entire grid at once may be unfeasible. In particular, after a lengthy outage during summer, all buildings will be warm, and if the power were restored at once, the demand from air conditioning units alone would be more than the grid could supply. In colder climates, a similar issue can occur in winter with the use of heating devices. In a larger grid, the black start will often involve starting multiple "islands" of generation (each supplying local load areas), and then synchronizing and reconnecting these islands 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. There are multiple methods of commencing a black start: 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 (i.e. suitable valleys for dams), the interconnectivity with other generating networks, and the response time necessary for the black start process.


Also Known As
Black start
Related Terms
transmission lineselectric powerpowertransmission lineturbinebioenergysystemsmart grid
References
  1. Glossary of Terms Used in Reliability Standards


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