IEEE 421.1:2007 pdf free download

IEEE 421.1:2007 pdf free download.IEEE Standard Definitions for Excitation Systems for Synchronous Machines.
3.Th excitation system duty cycle: An initial operating condition and a subsequent sequence of events of specified duration to which the excitation system will be exposed.
NOTE—The duty cycle usually invokes a three-phase fault of specified duration that is located electrically close to the synchronous machine. Its pnmaiy puqosc is to specitr the duty that the excitation system componcnts can withstand without incurring mis-operation or damage.
3.29 excitation system nominal response: The rate of increase of the excitation system output voltage determined from the excitation system voltage response curve, divided by the rated field voltage. This rate, if maintained constant (curve ac). would develop the same voltage-time area as obtained from the response (curve ab) over the first half-second interval (unless a different time interval is specified).
NOTE I Refer to Figure 2.
NOTE 2—The excitation system nominal response shall be determined with the excitation system voltage initially equal to the rated field voltage of the synchronous machine, after which the excitation system ceiling voltage is rapidly attained by introducing a specified voltage error step.
NOTE 3—-The excitation system nominal response shall be detennined with the excitation system loaded with a resistance equal to the held resistance under rated load conditions and adequate inductance so that voltage drop effects and current and voltage waveforms are reasonably duplicated.
NOTE 4—For excitation systems whose supply depends on the synchronous machine voltage and (if applicable) current, the nature of the power system disturbance and specific design parameters of the excitation system and the synchronous machine influence the excitation system output. For such systems, the excitation system nominal response shall be determined considering a specitied supply voltage usually rated voltage) and (if applicable) synchronous machine current.
NOTE 5—lf for practical considerations, tests can only be made on individual components or the entire excitation system but only at partial or no-load, analytical methods may be used to predict pertbnnance with rated field voltage (see NOTE 1).
NOTE 6—For excitation systems employing a rotating exciter, the excitation system nominal response shall be determined am rated speed.
NOTE 7- Not normall> used in the specification of static excitation systems. There is a potential conflict if ceiling voltage is also specified.