IEEE 421.1:2007 pdf free download – IEEE Standard Definitions for Excitation Systemsfor Synchronous Machines
3.30 excitation system output terminals: The place of output from the equipment comprising theexcitation system. These terminals may be identical with the field winding terminals.
3.31 excitation system rated current: The direct current at the excitation system output terminals that theexcitation system can supply under defined conditions of its operation.This current is at least that valuerequired by the synchronous machine under the most demanding continuous operating conditions(generally resulting from synchronous machine voltage, frequency, and power factor variations).
3.32 excitation system rated voltage: The direct voltage at the excitation system output terminals that theexcitation system can provide when delivering excitation system rated current under rated continuous loadconditions of the synchronous machine with its field winding at 1) 75 C for field windings designed tooperate at rating with a temperature rise of 60 C or less; or 2) 100 C for field windings designed tooperate at rating with a temperature rise greater than 60 °C.
3.33 excitation system stabilizer: A function that serves to modify the voltage regulator forward signal byeither series or feedback compensation to improve the dynamic performance of the excitation controlsystem.
3.34 excitation system voltage response time: The time in seconds for the excitation voltage to attain 95%of the difference between ceiling voltage and rated field voltage under specified conditions.
3.35 exciter: The equipment that provides the field current for the excitation of a synchronous machine.3.36 fault current limiter: A function that acts to prevent the stator current from exceeding a preset valueduring steady-state operation of the generator with a short-circuit applied to its output. The limiter acts tolimit fault current by decreasing excitation.Also known as line current limiter.
3.37 field current/voltage limiter: A control function that acts to prevent the field current or voltage fromexceeding a preset value.See also: overexcitation limiter.
3.38 field discharge circuit breaker: A circuit breaker having main contacts for energizing and de-energizing the field of a synchronous machine or rotating exciter and having discharge contacts for short-circuiting the field through a discharge resistor prior to the opening of the circuit breaker main contacts.The discharge contacts also disconnect the field from the discharge resistor following the closing of themain contacts.
NOTE 1—When used in the main field of a synchronous machine the circuit breaker is designated as a main fielddischarge circuit breaker.
NOTE 2—When used in the field circuit of a rotating exciter of the main machine, the circuit breaker is designated asan exciter field discharge circuit breaker. See [B1].
3.39 field flashing: Momentary application of dc power to the field of a synchronous machine for thepurpose of building up terminal voltage.
3.40 field forcing: A control action that rapidly drives the field voltage of a synchronous machine in thepositive or in the negative direction.
3.41 field voltage/field current regulator: A regulator that functions to maintain the field voltage/ieldcurrent at a predetermined value.
3.42 field winding: A winding on cither the stationary or the rotating part of a synchronous machine whosesole purpose is the production of the main electromagnetic field of the machine.
3.47 large signal performance: Response of an excitation control system, excitation system, or elementsof an excitation system to signals that are large enough that nonlinearities must be included in the analysisof the response to obtain realistic results.