ANSI standards (protection) – index Current protection functions •
ANSI 50/51 – Phase overcurrent ANSI 50N/51N or 50G/51G – Earth fault or sensitive earth fault
•
ANSI 50BF – Breaker failure
•
ANSI 4 !Ne"ative se#uence / un$alance
•
ANSI 4%&'S – (her)al overloa*
•
Directional power protection functions • •
ANSI +,P – -irectional active over.oer ANSI +,/40 – -irectional reactive over.oer
Voltage protection functions •
ANSI ,- – Positive se#uence un*ervolta"e ANSI ,& – &e)anent un*ervolta"e
•
ANSI , – Phase!to!.hase un*ervolta"e
•
ANSI 5% – Phase!to!.hase overvolta"e
•
ANSI 5%N – Neutral volta"e *is.lace)ent
•
ANSI 4 – Ne"ative se#uence volta"e
•
Recloser •
ANSI % – &eclose the circuit $reaker after tri..in"
Directional current protection •
ANSI – -irectional .hase overcurrent ANSI N/N2 – -irectional earth fault
•
ANSI N/N2 t3.e 1
•
ANSI N/N2 t3.e ,
•
ANSI N/N2 t3.e +
•
Machine protection functions •
ANSI + – Phase un*ercurrent ANSI 4/51&/14 – ocke* rotor / e6cessiv e6cessive e startin" ti)e
•
ANSI – Starts .er hour
•
ANSI 507/517 – 7olta"e!restraine* 7olta"e!restraine* overcurr overcurrent ent
•
ANSI ,/+ – (her)ostat8 Buchhol98 "as8 .ressure8 te).erature *etection
•
ANSI +/4%( – (e).erature )onitorin" $3 &(-
•
Frequency protection functions •
ANSI 1: – ;verfre#uenc3 ANSI 1 –
•
ANSI 1& – &ate of chan"e of fre#uenc3 =&;2;F>
•
Current protection functions ANSI 50/51 – Phase overcurrent
Three-phase protection against overloads and phase-to-phase short-circuits. ANSI 50N/51N or 50G/51G – Earth fault
Earth fault protection based on measured or calculated residual current values: • •
ANSI 50N/51N? resi*ual current calculate* or )easure* $3 + .hase current sensors ANSI 50G/51G? resi*ual current )easure* *irectl3 $3 a s.eci@c sensor
ANSI 50BF – Breaker failure
If a breaker fails to be triggered by a tripping order, as detected by the non-extinction of the fault current, this backup protection sends a tripping order to the upstream or adjacent breakers. ANSI 4 – Ne!ative se"uence / un#alance
rotection against phase unbalance, detected by the measurement of negative se!uence current: • •
Sensitive .rotection to *etect ,!.hase faults at the en*s of lon" lines Protection of e#ui.)ent a"ainst te).erature $uil*!u.8 cause* $3 an un$alance* .oer su..l38 .hase inversion or loss of .hase8 an* a"ainst .hase current un$alance
ANSI 4$%&S – 'her(al overloa)
rotection against thermal damage caused by overloads on machines "transformers, motors or generators#. The thermal capacity used is calculated according to a mathematical model $hich takes into account:
•
2urrent &'S values A)$ient te).erature
•
Ne"ative se#uence current8 a cause of )otor rotor te).erature rise
•
%&'I index
Recloser ANSI *$
%utomation device used to limit do$n time after tripping due to transient or semipermanent faults on overhead lines. The recloser orders automatic reclosing of the breaking device after the time delay re!uired to restore the insulation has elapsed. (ecloser operation is easy to adapt for different operating modes by parameter setting. %&'I index
Directional current protection ANSI * – +irectional ,hase overcurrent
hase-to-phase short-circuit protection, $ith selective tripping according to fault current direction. It comprises a phase overcurrent function associated $ith direction detection, and picks up if the phase overcurrent function in the chosen direction "line or busbar# is activated for at least one of the ) phases. ANSI *N/*N- – +irectional earth fault
Earth fault protection, $ith selective tripping according to fault current direction. ) types of operation: • •
•
t3.e 1? the .rotection function uses the .roection of the I0 vector t3.e ,? the .rotection function uses the I0 vector )a"nitu*e ith half!.lane tri..in" 9one t3.e +? the .rotection function uses the I0 vector )a"nitu*e ith an"ular sector tri..in" 9one
ANSI *N/*N- t.,e 1
*irectional earth fault protection for impedant, isolated or compensated neutralsystems, based on the projection of measured residual current. ANSI *N/*N- t.,e
*irectional overcurrent protection for impedance and solidly earthed systems, based on measured or calculated residual current. It comprises an earth fault function associated $ith direction detection, and picks up if the earth fault function in the chosen direction "line or busbar# is activated. ANSI *N/*N- t.,e
*irectional overcurrent protection for distribution net$orks in $hich the neutral earthing system varies according to the operating mode, based on measured residual current. It comprises an earth fault function associated $ith direction detection "angular sector tripping +one defined by adjustable angles#, and picks up if the earth fault function in the chosen direction "line or busbar# is activated. %&'I index
Directional power protection functions ANSI P – +irectional active over,oer
T$o-$ay protection based on calculated active po$er, for the follo$ing applications: • •
active over.oer .rotection to *etect overloa*s an* allo loa* she**in" reverse active .oer .rotection? o
o
a"ainst "enerators runnin" like )otors hen the "enerators consu)e active .oer a"ainst )otors runnin" like "enerators hen the )otors su..l3 active .oer
ANSI 2/40 – +irectional reactive over,oer
T$o-$ay protection based on calculated reactive po$er to detect field loss on synchronous machines: •
•
reactive over.oer .rotection for )otors hich consu)e )ore reactive .oer ith @el* loss reverse reactive over.oer .rotection for "enerators hich consu)e reactive .oer ith @el* lossC
%&'I index
Machine protection functions ANSI * – Phase un)ercurrent
rotection of pumps against the conse!uences of a loss of priming by the detection of motor no-load operation. It is sensitive to a minimum of current in phase , remains stable during breaker tripping and may be inhibited by a logic input. ANSI 43/51%/14 – ocke) rotor / ecessive startin! ti(e
rotection of motors against overheating caused by: •
•
e6cessive )otor startin" ti)e *ue to overloa*s =eC"C conve3or> or insuDcient su..l3 volta"eC (he reacceleration of a )otor that is not shut *on8 in*icate* $3 a lo"ic in.ut8 )a3 $e consi*ere* as startin"C locke* rotor *ue to )otor loa* =eC"C crusher>? o
o
in nor)al o.eration8 after a nor)al start *irectl3 u.on startin"8 $efore the *etection of e6cessive startin" ti)e8 ith *etection of locke* rotor $3 a 9ero s.ee* *etector connecte* to a lo"ic in.ut8 or $3 the un*ers.ee* functionC
ANSI – Starts ,er hour
rotection against motor overheating caused by: •
too fre#uent starts? )otor ener"i9in" is inhi$ite* hen the )a6i)u) alloa$le nu)$er of starts is reache*8 after countin" of? starts .er hour =or a*usta$le .erio*> o o
•
consecutive )otor hot or col* starts =reacceleration of a )otor that is not shut *on8 in*icate* $3 a lo"ic in.ut8 )a3 $e counte* as a start>
starts too close to"ether in ti)e? )otor re!ener"i9in" after a shut*on is onl3 alloe* after an a*usta$le aitin" ti)eC
ANSI 506/516 – 6olta!e7restraine) overcurrent
hase-to-phase short-circuit protection, for generators. The current tripping set point is voltage-adjusted in order to be sensitive to faults close to the generator $hich cause voltage drops and lo$ers the short-circuit current. ANSI / – 'her(ostat/Buchhol8
rotection of transformers against temperature rise and internal faults via logic inputs linked to devices integrated in the transformer. ANSI 3/4$' – 'e(,erature (onitorin!
rotection that detects abnormal temperature build-up by measuring the temperature inside e!uipment fitted $ith sensors: • •
transfor)er? .rotection of .ri)ar3 an* secon*ar3 in*in"s )otor an* "enerator? .rotection of stator in*in"s an* $earin"sC
%&'I index
Voltage protection functions ANSI *+ – Positive se"uence un)ervolta!e
rotection of motors against faulty operation due to insufficient or unbalanced net$ork voltage, and detection of reverse rotation direction. ANSI *% – %e(anent un)ervolta!e
rotection used to check that remanent voltage sustained by rotating machines has been cleared before allo$ing the busbar supplying the machines to be re-energi+ed, to avoid electrical and mechanical transients. ANSI * – 9n)ervolta!e
rotection of motors against voltage sags or detection of abnormally lo$ net$ork voltage to trigger automatic load shedding or source transfer. orks $ith phase-to-phase voltage. ANSI 5$ – :vervolta!e
*etection of abnormally high net$ork voltage or checking for sufficient voltage to enable source transfer. orks $ith phase-to-phase or phase-to-neutral voltage, each voltage being monitored separately. ANSI 5$N – Neutral volta!e )is,lace(ent
*etection of insulation faults by measuring residual voltage in isolated neutral systems. ANSI 4* – Ne!ative se"uence overvolta!e
rotection against phase unbalance resulting from phase inversion, unbalanced supply or distant fault, detected by the measurement of negative se!uence voltage. %&'I index
re!uenc" protection functions ANSI 31; – :verfre"uenc.
*etection of abnormally high fre!uency compared to the rated fre!uency, to monitor po$er supply !uality. ANSI 31 – 9n)erfre"uenc.
*etection of abnormally lo$ fre!uency compared to the rated fre!uency, to monitor po$er supply !uality. The protection may be used for overall tripping or load shedding. rotection stability is ensured in the event of the loss of the main source and presence of remanent voltage by a restraint in the event of a continuous decrease of the fre!uency, $hich is activated by parameter setting. ANSI 31% – %ate of chan!e of fre"uenc.
rotection function used for fast disconnection of a generator or load shedding control. /ased on the calculation of the fre!uency variation, it is insensitive to transient voltage disturbances and therefore more stable than a phase-shift protection function.
Disconnection In installations $ith autonomous production means connected to a utility, the 0rate of change of fre!uency1 protection function is used to detect loss of the main system in vie$ of opening the incoming circuit breaker to: • •
.rotect the "enerators fro) a reconnection ithout checkin" s3nchroni9ation avoi* su..l3in" loa*s outsi*e the installationC
#oad shedding The 0rate of change of fre!uency1 protection function is used for load shedding in combination $ith the underfre!uency protection to: • •
either accelerate she**in" in the event of a lar"e overloa* or inhi$it she**in" folloin" a su**en *ro. in fre#uenc3 *ue to a .ro$le) that shoul* not $e solve* $3 she**in"C
%&'I index
