Droop speed control

In electricity generation, droop speed control is the primary instantaneous system using net frequency deviations to distribute with stability load changes over generating plants.

For stable operation of the electrical grid of North America, power plants operate with a five percent speed droop.[1][citation needed] This means the full-load speed is 100% and the no-load speed is 105%. This is required for the stable operation of the net without hunting and dropouts of power plants. Normally the changes in speed are minor due to inertia of the total rotating mass of all generators and motors running in the net.[2] Adjustments in power output are made by slowly raising the droop curve by increasing the spring pressure on a centrifugal governor or engine control unit adjustment. Generally this is a basic system requirement for all power plants because the older and newer plants have to be compatible in response to the instantaneous changes in frequency without depending on outside communication. Voltage control of several power sources is not practical because there would not be any independent feedback, resulting in the total load being put on one power plant.[3]

Contiguous United States power transmission grid consists of 300,000 km of lines operated by 500 companies.

It can be mathematically shown that if all machines synchronized to a system have the same droop speed control, they will share load proportionate to the machine ratings.[4]

The thousands of AC generators are running synchronously with the power grid which acts like an infinite sink. Next to the inertia given by the parallel operation of synchronous generators,[5] the frequency speed droop is the primary instantaneous parameter in control of an individual power plant's power output (KW).[6]

 S = \frac {\Delta f_N} {f_N}

S is the ratio of frequency deviation when comparing the load versus the nominal frequency.

Notes

  1. ^ http://www.control.com/thread/1026221805
  2. ^ http://www.nationalgrid.com/uk/Electricity/Data/Realtime/Frequency/Freq60.htm
  3. ^ Speed Droop and Power Generation. Application Note 01302. 2. Woodward. Speed
  4. ^ William D. Stevenson, Jr. Elements of Power System Analysis Third Edition,McGraw-Hill, New York (1975) ISBN 0070612854 page 378-379
  5. ^ VSYNC-Project
  6. ^ Whitaker, Jerry C. (2006). AC power systems handbook. Boca Raton, FL: Taylor and Francis. p. 35. ISBN 9780849340345. 

See also

Further reading


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Control system — For other uses, see Control system (disambiguation). A control system is a device, or set of devices to manage, command, direct or regulate the behavior of other devices or system. There are two common classes of control systems, with many… …   Wikipedia

  • droop compensator — A mechanism in the helicopter engine to prevent the rotor speed from decreasing as the load is applied to the engine. A linkage between the collective pitch control and the turbine speed governor that adjusts for the increased load the rotor… …   Aviation dictionary

  • Flight control surfaces — Aircraft flight control surfaces allow a pilot to adjust and control the aircraft s flight attitude.Development of an effective set of flight controls was a critical advance in the development of the aircraft. Early efforts at fixed wing aircraft …   Wikipedia

  • Diesel generator — A Cummins diesel generator of 500kVA in a tourist resort in Egypt …   Wikipedia

  • Steam turbine — A rotor of a modern steam turbine, used in a power plant A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into rotary motion. Its modern manifestation was invented by Sir Charles Parsons… …   Wikipedia

  • Dynamic demand (electric power) — Dynamic Demand is the name of a semi passive technology for adjusting load demands on an electrical power grid. (It is also the name of an independent not for profit organization in the UK supported by a charitable grant from the Esmée Fairbairn… …   Wikipedia

  • Electric power transmission — Electric transmission redirects here. For vehicle transmissions, see diesel electric transmission. 400 kV high tension transmission lines near Madrid Electric power transmission or high voltage electric transmission is the bulk transfer of… …   Wikipedia

  • Cyberwarfare — Cyberwar redirects here. For the video game, see Cyberwar (video game). For the 2004 movie, see Cyber Wars (film). For the 1999 MMOG, see Cyber Wars. Computer security Secure operating systems Security architecture Security by design …   Wikipedia

  • Concorde — For other uses, see Concorde (disambiguation). Concorde Role Supersonic airliner …   Wikipedia

  • PID controller — A block diagram of a PID controller A proportional–integral–derivative controller (PID controller) is a generic control loop feedback mechanism (controller) widely used in industrial control systems – a PID is the most commonly used feedback… …   Wikipedia


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.