IEEE 421.1-2007 pdf free download – IEEE Standard Definitions for Excitation Systems for Synchronous Machines.
3. Definitions For the purposes of this standard, the following terms and definitions apply. The Authoritative Dictionary of IEEE Standards Terms [B11] 3 should be referenced for terms not defined in this clause.
3.1 ac field breaker: A circuit breaker used to disconnect the excitation system from the power potential transformer (PPT) or ac supply. See also: de-excitation.
3.2 ac regulator: See: voltage regulator. 3.3 adjuster: A device or function by which the set point is determined.
3.4 air-gap field voltage: The synchronous machine field voltage required to produce rated voltage on the air-gap line of the synchronous machine with its field winding at 1) 75 °C for field windings designed to operate at rating with a temperature rise of 60 °C or less; or 2) 100 °C for field windings designed to operate at rating with a temperature rise greater than 60 °C.
NOTE—This defines one per unit excitation system voltage for use in computer representation of excitation systems.
3.5 air-gap line: The extended straight line part of the no-load saturation curve of the synchronous machine.
3.6 alternator-rectifier exciter: An exciter whose energy is derived from an alternator and converted to direct current by rectifiers. The exciter includes an alternator and power rectifiers that may be either noncontrolled or controlled, including gate circuitry. It is exclusive of input control elements. The alternator may be driven by any type of prime mover, most commonly the shaft of the synchronous machine. The rectifiers may be stationary or rotating with the alternator shaft.
3.7 automatic control: In excitation control system usage, automatic control refers to maintaining synchronous machine terminal voltage at a predetermined level without operator action, over the operating range of the synchronous machine.
NOTE—Voltage regulation may be modified by the action of load current compensators, power factor or var controllers, power system stabilizers, or may be constrained by the action of various limiters included in the excitation system.
3M automatic soltage regulator (AVk(: A term oflen us-ed to designate either the voltage regulator alone or the complete control system comprised of limiters, etc. SEe aLso vi nchrnnuus machine regulator
3.9 autotracklng: A (unction that causes the output of a control channel in the standby mode to follow the action of an alive control channel, for example. autotr.scking of the manual control to follow the automatic control, Also called a follower.
3.11) ausiliary winding eseitation s)vteni: An excitation system whose energy ts derived from a separate dedicated power winding in the main generator’s statsir
NOTE—See Figure Ale
3.11 brushless eseiter An alternator-rectifier exciter employing rotating rectifiers with a direct connection to the synchronous machine field, thus eliminating the need for hmshes
NOTE—See Figure 46.
3.12 buinpless tranxrer: A transfer between two control nssles that results in negligible change in synchronous machine output. See also null balance
3.13 ceili.g curreNt: The masimum field current that the excitation system is designed to supply. Typically, this is related to the thermal capability of the excitation system equipment or the synchronous machine field circuit ciahility See crisr,: oserrxcitaliou limiter
3.14 ceiling voltage: The maximum direct voltage that the excitation system is designed t supply from it. terminals under defined conditions,
NO 0± I —[he no-load ceiling voltage is detcrnunest vs tb the excitation system supplying nutomnal csimm cit
NOTE 2—The ceiling vuttage mauler load ma determined with the excitation system supplying synchronous machine rated field current.
NOEL 3—For as escmiatmuo system whose supply depenmis on the synchronous machine voltage and (if applicable) cvmrremu, the nature of poser system disturbance and specific design parameters of the excitation system and the synelvonoes machine influence the excitation system outpt.a. For such systems, the ceiling voltage is detennined comssmdeimng a specified supply vottage I usually ititol voltage) and (if applicable) svmsehrommous machine current.
NOTE 4 For excitation systems employing a renaming exciter, the ceiling voltage is determined at rated speed.
3.15 commspound source-rectifier exciter: An exciter whose energy is derived fmom the eurtm.’nts and potentials of the ac ternsinals of the synchronous machine and converted to direct current by rectifiers. The exciter includes the power tr’ansfomsers (current and potemial). reactors (if rcquiredt amid rectifiers that may he either noncontrolled or controlled, including gate cireuirn. It is exclusive of input control elemisents.
3.16 crmiwhar: In excitation system usage, a circuit designed to provide a cotsduetiout path for field current flow to present excessive field voltagt Triggered semiconductors with series resistors or inductors are commonly used. Non-linear resistors tiny altematively provide this ftmnetiomt.
NOTE—See Figure A. I 7km.
3.17 current boost: An excitation system auxiliaty supply that acts to increase the available power supplied to the field winding, typically during fault conditions sslscre the terminal voltage is lower and current is higher titan normal.
3.1$ current boost exciter: An exciter whose energy is derived front currents at the ac terminals of the synchronous machine and converted to direct current by rectifiers. The current boost system output is added directly with a potential source exciter rectifier as a separate rectifier system. The current boost sysimmi may include power current transformets. and either noncontmolled rectifiers or controlled rectifiers. with gate circuitry.IEEE 421.1 pdf download.