Pr ot ect i veDevi ceNumber s Pr o t ec t i v er el a y sar ecommonl yr ef er r edt obys t andar dde vi c enumber s .Fore x ampl e ,at i meov er c ur r ent r el a yi sdes i gnat eda51dev i c e,whi l eani ns t ant aneousov er c ur r enti sa50de vi c e.Mul t i f unc t i onr el a ys h av ec omb i n at i o nsofd ev i c en umb er s .A2 7/ 5 9d ev i c e ,f ore x amp l e,i sac omb i na t i o nu nd er / o v erv o l t a ge r el ay .Let t er scanbeaddedt oc l ar i f yappl i c at i on( 87Tf ort r ans f or merdi ffer ent i al ,59G f orgr ound ov er v ol t age) . •
1 – Master Element
•
2 – Time Delay Starting or Closing Relay
•
3 – Checking or Interlocking Relay
•
4 – Master Contactor
•
5 – Stopping Deice
•
! – Starting Circ"it #reaker
•
$ – Rate o% Change Relay
•
& – Control 'o(er Disconnecting Deice
•
) – Reersing Deice
•
1* – +nit Se,"ence S(itch
•
11 – M"lti-%"nction Deice
•
12 – .erspee/ Deice
•
13 – Synchrono"s-s Synchrono"s-spee/ pee/ Deice
•
14 – +n/erspee/ Deice
•
15 – Spee/ – or 0re,"ency Matching Deice
•
1! – Data Comm"nications Deice
•
1$ – Sh"nting or Discharg Discharge e S(itch
•
1& – cceler ccelerating ating or Deceleratin Decelerating g Deice
•
1) – Starting to R"nning Transition Contactor
•
2* – Electrically .perate/ ale
•
21 – Distance Relay
•
22 – E,"alier Circ"it #reaker
•
23 – Temperat"re Control Deice
•
24 – olts 'er ert Relay
•
25 – Synchroniin Synchroniing g or Synchronis Synchronism-Check m-Check Deice
•
2! – pparat"s Thermal Deice
•
2$ – +n/eroltage Relay
•
2& – 0lame /etector
•
2) – Isolating Contactor or S(itch
•
3* – nn"nciator Relay
•
31 – Separate E6citation E6citation Deice
•
32 – Directional 'o(er Relay
•
33 – 'osition S(itch
•
34 – Master Se,"ence Deice
•
35 – #r"sh-.perating or Slip-Ring Short-Circ"iting Deice
•
3! – 'olarity or 'olariing oltage Deices
•
3$ – +n/erc"rrent or +n/erpo(er Relay
•
3& – #earing 'rotectie Deice
•
3) – Mechanical Con/ition Monitor
•
4* – 0iel/ 7oer8"n/er e6citation9 Relay
•
41 – 0iel/ Circ"it #reaker
•
42 – R"nning Circ"it #reaker
•
43 – Man"al Trans%er or Selector Deice
•
44 – +nit Se,"ence Starting Relay
•
45 – :normal tmospheric tmospheric Con/ition Monitor
•
4! – Reerse-phase or 'hase-#alance C"rrent Relay
•
4$ – 'hase-Se,"ence or 'hase-#alance oltage Relay
•
4& – Incomplete Se,"ence Relay
•
4) – Machine or Trans%ormer Thermal Relay
•
5* – Instantaneo"s .erc"rrent Relay
•
51 – C Inerse Time .erc"rrent Relay
•
52 – C Circ"it #reaker
•
53 – E6citer or DC ;enerator Relay
•
54 – T"rning ;ear Engaging Deice
•
55 – 'o(er 0actor Relay
•
5! – 0iel/ pplication Relay
•
5$ – Short-Circ" Short-Circ"iting iting or ;ro"n/ing Deice
•
5& – Recti
•
5) – .eroltage Relay
•
!* – oltage or C"rrent #alance Relay
•
!1 – Density S(itch or Sensor
•
!2 – Time-Delay Stopping or .pening Relay
•
!3 – 'ress"re S(itch
•
!4 – ;ro"n/ Detector Relay
•
!5 – ;oernor
•
!! – =otching or >ogging Deice
•
!$ – C Directional .erc"rrent Relay
•
!& – #locking or ?."t-o%-Step? Relay
•
!) – 'ermissie Control Deice
•
$* – Rheostat
•
$1 – @i,"i/ @eel S(itch
•
$2 – DC Circ"it #reaker
•
$3 – @oa/-Resistor Contactor
•
$4 – larm Relay
•
$5 – 'osition Changing Mechanism
•
$! – DC .erc"rrent Relay
•
$$ – Telemetering Deice
•
$& – 'hase-ngle Meas"ring Relay
•
$) – C Reclosing Relay
•
&* – 0lo( S(itch
•
&1 – 0re,"ency Relay
•
&2 – DC Reclosing Relay
•
&3 – "tomatic Selectie Control or Trans%er Relay
•
&4 – .perating Mechanism
•
&5 – Comm"nicationsCarrier or 'ilot-Aire Relay
•
&! – @ocko"t Relay
•
&$ – DiBerential 'rotectie Relay
•
&& – "6iliary Motor or Motor ;enerator
•
&) – @ine S(itch
•
)* – Reg"lating Deice
•
)1 – oltage Directional Relay
•
)2 – oltage an/ 'o(er Directional Relay
•
)3 – 0iel/ Changing Contactor
•
)4 – Tripping or Trip-0ree Relay
•
)5 to )) – For specifc applications where other numbers are not suitable
* or a ull defnition o each unction, please reer to the ANSI/IEEE C3!" standard
Pr efixesandSuffixes L et t e r sa ndnu mb er sma yb eu s edasp r e fi x e sors u ffix e st ode v i c ef u nc t i o nn umb er st opr o v i d eamo r e s p ec i fi cde fi ni t i ono ft h ef u nc t i o n.Pr e fix e sa nds uffix e ss h ou l d ,h owe v er ,b eu se do nl ywhe nt h ey a cc omp l i s haus e f ul p ur p os e. Auxiliary devices
Main device
•
C - Closing relay8contactor
•
- larm8a"6iliary po(er
•
C@ - "6iliary relay close/
•
C - lternating c"rrent
•
CS - Control s(itch
•
= - no/e
•
D - ?Do(n? position s(itch relay
•
# - #attery :lo(er :"s
•
@- @o(ering relay
•
# - #rake
•
. - .pening relay8contactor
•
#@ - #lock 7ale9
•
.' - "6iliary relay open
•
#' - #ypass
•
'# - '"sh :"tton
•
#T - #"s tie
•
R - Raising relay
•
C - Capacitor con/enser c
•
+ - ?+'? position s(itch relay
•
- "6iliary relay
compressor •
C - Catho/e
•
- "6iliary relay
•
C - Check 7ale9
•
F - "6iliary relay
•
D - Discharge 7ale9
•
DC - Direct c"rrent
•
E - E6citer
•
0 - 0ee/er
Actuating quantities •
-ir8amperes8alternating
•
; - ;enerator8gro"n/
•
C - C"rrent
•
- eater8ho"sing
•
D - Direct8/ischarge
•
@ - @ine logic
•
E - Electrolyte
•
M - Motor metering
•
0 - 0re,"ency8Go(8%a"lt
•
M.C - Mechanism operate
•
;' - ;as press"re
•
= - =et(ork ne"tral
•
- E6plosie8harmonics
•
' - '"mp phase comparis
•
I* - Fero se,"ence c"rrent
•
R - Reactor recti
•
I- I2 - =egatie se,"ence c"rrent
•
S - Synchroniing secon/a
•
IH I1 - 'ositie se,"ence c"rrent
•
T -Trans%ormer thyratron
•
T - Trans%ormer 7high-olt
•
> - DiBerential
•
@ - @eel8li,"i/
•
T@ - Trans%ormer 7lo(-olta
•
' - 'o(er8press"re
•
TM - Telemeter
•
'0 - 'o(er %actor
•
T.C - Tr"ck-operate/ cont
•
- .il
•
TT - Trans%ormer 7tertiary-
•
S - Spee/8s"ction8smoke
•
•
+ - +nit
T - Temperat"re
•
- oltage8olts8ac""m
•
R -Reactie po(er
•
# - i:ration
•
# - #rake
•
A - ater8(atts
•
C - Coil con/enser capaci
•
CC - Closing coil closing c
•
C - ol/ing coil
•
M - .perating motor
Other sufx letters
Main device parts
•
- ccelerating a"tomatic
•
M0 - 0ly-:all motor
•
# - #locking :ack"p
•
M@ - @oa/-limit motor
•
#0 - #reaker %ail"re
•
MS - Spee/ a/J"sting or sy
•
C - Close col/
•
.C - .pening contactor
•
D - Decelerating /etonate /o(n /isengage/
•
S - Solenoi/
•
E - Emergency engage/
•
SI - Seal-in
•
0 - 0ail"re %or(ar/
•
T - Target
•
;' - ;eneral p"rpose
•
TC Trip coil
•
- ot high
•
•
IF - igh impe/ance %a"lt
•
R - an/ reset
•
S - igh spee/
- ale
Reerence positions o device
•
@ - @e%t local lo( lo(er lea/ing
•
/J"sting means - @o( or
•
M - Man"al
•
Cl"tch - Disengage/ positi
•
. - .pen oer
•
Contactor - De-energie/
•
.00 - .B
•
Contactor 7latche/-in type9
•
.= - .n
•
Density s(itch - Stan/ar/
•
' - 'olariing
•
Disconnecting s(itch - Ma
•
R - Right raise reclosing receiing remote reerse
•
0lo( /etector - @o(est Go
•
S - Sen/ing s(ing
•
;ate - Close/ position
•
SS - Semi-high spee/
•
@eel /etector - @o(est le
•
T - Test trip trailing
•
@oa/-:reak s(itch - Main
•
TDC - Time-/elay closing contact
•
'o(er circ"it :reaker - Mai
•
TDD. - Time /elaye/ relay coil /rop-o"t
•
'o(er electro/es - Ma6im"
•
TD. - Time-/elay opening contact
•
'ress"re s(itch - @o(est p
•
TD'+ - Time /elaye/ relay coil pick"p
•
Reclos"re - Main contactor
•
TD - Total harmonic /istortion
•
Relay - De-energie/ posit
•
Relay 7latche/-in type9
•
Rheostat - Ma6im"m resis
•
Spee/ s(itch - @o(est spe
•
+ - +p "n/er
ANSII ECCompar i son ANSI
I EC60617
Des c r i pt i on
21FL
FL OC
Faul tl oc at or
21G
Z<
Under i mpedanc e
24
U/ f >
Ov er ex c i t at i on
25
SYNC
Sy nc hr oni s at i onc hec k
27
U<
Under v ol t age
32
P→
Di r ec t i onal powerr el ay 3 2P ,P→,-a c t i v epo we r 3 2 Q,Q→ -r e a c t i v ep o we r p o we r
37
I <
Nondi r ec t i onal under c ur r ent
40
X<
Under ex c i t at i on
•
Tap changer - Center tap
•
Temperat"re relay - @o(es
•
T"rning gear - Disengage/
•
ac""m s(itch - @o(est pr
•
ale - Close/ position
•
i:ration /etector - Minim
46
I 2>
Negat i v ephas es equenc e
47
U2>
Phas es equenc ev ol t agepr ot ec t i on
48,14,66
I s ² t , n<
St ar t ups uper v i s i onf ormot or s
49F
I th>
Ther mal pr ot ec t i onf orc abl es
49M/ 49G/ 49T
Thr eephas et her mal pr ot ec t i onf ormac hi nes M -mo t or ,G -ge ner at or s ,T-t r ans f or mer
50N/ 51N
I *>
Nondi r ec t i onal ear t hf aul t
51
I >
Nondi r ec t i onal ov er c ur r ent 51C,I >-s huntc apac i t or s 5 1V,I ( U) >-v o l t a ged ep en da nt
59
U>
Ov er v ol t age 5 9N,U0>-r es i dual o v er v ol t age
67
I >→
Di r ec t i onal ov er c ur r ent 67N,I 0>→ -di r ec t i onal ear t hf aul t
68
I 2>
T r ans f or mer / mot ori nr us hc ur r ent
79
0→1
Aut or ec l os ur e
81
f
Fr equenc yr el ay 8 1N,f <-u nde r f r qu en cy 8 1O,f >-o v er f r e qu enc y
87
∆I >
Di ffer ent i al pr ot ec t i on 8 7G,∆I >-g en er a t o r 8 7 M,∆I >-mo t o r 8 7T ,∆I >-t r ans f or mer 87N,∆I r es t r i c t edear t hf aul t *>-
Notes# $! or hi%h set and instantaneous trippin%, &'& can be replaced with &''& or &''& 2.' 3' c anbepl ac edbef or edes i gnat i onst oi ndi c at et hr eephas e,i . e.3I < -Se emo r ea t :ht t p: / / my el ec t r i c al . c om/ not es / ent r y i d/ 148/ ans i i eeepr ot ec t i v edev i c en u mb e r i n g # s t h a s h . p q Tp wu k A. d p uf
Posted by ecsanyi on Wednesday, April 14, 2010 at 10:23 pm | Technical Articles | Categories | !bmit Article
ANSI/IEC Relay Symbols "",#00 $ie%s There are t%o methods &or indicating protection relay &!nctions in common !se' (ne is gi$en in A)* tandard C3#+ 2, and !ses a n!mbering system &or $ario!s &!nctions' The &!nctions are s!pplemented by letters %here ampli&ication o& the &!nction is re!ired' The other is gi$en in *-C .0.1#, and !ses graphical symbols' To assist the Protection -ngineer in con$erting &rom one system to the other, a select list o& A)* de$ice n!mbers and their *-C e!i$alents is gi$en in /ig!re A2'1'
Posted by ecsanyi on onday, eptember 14, 200 at 11:2 pm | Technical Articles | Categories | !bmit Article
Protection relays – important informations 14,"#4 $ie%s
Ad!stment (& Protection elays Parameters
The s!ccess&!l operation o& an distrib!tion system depends on the proper selection and setting o& s%itchgear relays' Protecti$e relays are arg!ably the least !nderstood component o& medi!m $oltage 56 circ!it protection' *n &act, somebelie$e that circ!it brea7ers operate by themsel$es, %itho!t direct initiation by protecti$e relays' (thers thin7 that the operation and coordination o& protecti$e relays is m!ch too complicated to !nderstand' 8et9s get into the details and eliminate these misbelie&s'
Background information The *--- tandard ictionary de&ines a circuit breaker as &ollo%s: A de$ice designed to open and close a circ!it by nona!tomatic means, and to open the circ!it a!tomatically on a predetermined o$erload o& c!rrent %itho!t in!ry to itsel& %hen properly applied %ithin its rating' ;y this de&inition, brea7ers are not tr!e circ!it brea7ers, since they do not open a!tomatically on o$erc!rrent' They are electrically operated po%er+s%itching de$ices, not operating !ntil directed by some e
circ!it brea7er' ensors and relays are !sed to detect the o$erc!rrent or other abnormal or !nacceptable condition and to signal the s%itching mechanism to operate' The circ!it brea7ers are the br!te+&orce s%itches %hile the sensors and relays are the brains that direct their &!nctioning' The sensors can be c!rrent trans&ormers 5 CTs6, potential trans&ormers 5PTs6, temperat!re or press!re instr!ments, &loat s%itches, tachometers, or any de$ice or combination o& de$ices that %ill respond to the condition or e$ent being monitored' *n s%itchgear application, the most common sensors are CTs to meas!re c!rrent and PTs to meas!re $oltage' The relays meas!re sensor o!tp!t and ca!se the brea7er to operate to protect the system %hen preset limits are e
Electromechanical relays
-lectromechanical relay
/or many years, protecti$e relays ha$e been electromechanical de$ices, b!ilt li7e &ine %atches, %ith great precision and o&ten %ith e%eled bearings' They ha$e earned a %ell+deser$ed rep!tation &or acc!racy, dependability, and reliability' There are t%o basic types o& operating mechanisms: the electromagnetic+attraction relay and the electromagnetic+ind!ction relay' agnetic attraction relays' agnetic+attraction relays, ha$e either a solenoid that p!lls in a pl!nger, or one or more electromagnets that attract a hinged armat!re' When the magnetic &orce is s!&&icient to o$ercome the restraining spring, the mo$able element begins to tra$el, and contin!es !ntil the contact5s6 close or the magnetic &orce is remo$ed' The pic7!p point is the c!rrent or $oltage at %hich the pl!nger or armat!re begins to mo$e and, in a s%itchgear relay, the pic7!p $al!e can be set $ery precisely' These relays are !s!ally instantaneo!s in action, %ith no intentional time delay, closing as soon a&ter pic7!p as the mechanical motion permits' Time delay can be added to this type o& relay by means o& a bello%s, dashpot, or a cloc7%or7 escapement mechanism' o%e$er, timing acc!racy is considerably less precise than that o& ind!ction+type relays, and these relays are seldom !sed %ith time delay in s%itchgear applications' Attraction+type relays can operate %ith either AC or C on the coilsB there&ore, relays !sing this principle are a&&ected by the C component o& an asymmetrical &a!lt and m!st be set to allo% &or this' *nd!ction relays' *nd!ction relays, are a$ailable in many $ariations to pro$ide acc!rate pic7!p and time+c!rrent responses &or a %ide range o& simple or comple< system conditions' *nd!ction relays are basically ind!ction motors' The mo$ing element, or rotor, is !s!ally a metal dis7, altho!gh it sometimes may be a metal cylinder or c!p' The stator is one or more electromagnets %ith c!rrent or potential coils that ind!ce c!rrents in the dis7, ca!sing it to rotate' The dis7 motion is restrained by a spring !ntil the rotational &orces are s!&&icient to t!rn the dis7 and bring its mo$ing contact against the stationary contact, th!s closing the circ!it the relay is controlling' The greater the &a!lt being sensed, the greater the c!rrent in the coils, and the &aster the dis7 rotates' A calibrated ad!stment, called the time dial, sets the spacing bet%een the mo$ing and stationary contacts to $ary the operating time o& the relay &rom &ast 5contacts only slightly open6 to slo% 5contacts nearly a &!ll dis7 re$ol!tion apart6' eset action begins %hen the rotational &orce is remo$ed, either by closing the relay contact that trips a brea7er or by other%ise remo$ing the mal&!nction that the relay is sensing' The restraining spring resets the dis7 to its original position' The time re!ired to reset depends on the type o& relay and the time+dial setting 5contact spacing6' With m!ltiple magnetic coils, se$eral conditions o& $oltage and c!rrent can be sensed sim!ltaneo!sly' Their signals can be additi$e or s!btracti$e in act!ating the dis7' /or e
ost s%itchgear+type relays are enclosed in a semi&l!sh+mo!nting dra%o!t case' elays !s!ally are installed on the door o& the s%itchgear c!bicle' ensor and control %iring are bro!ght to connections on the case' The relay is inserted into the case and connected by means o& small s%itches or abridging pl!g, depending on the man!&act!rer' *t can be disconnected and %ithdra%n &rom the case %itho!t dist!rbing the %iring' When the relay is disconnected, the CT connections in the case are a!tomatically shorted to short circ!it the CT secondary %inding and protect the CT &rom o$er$oltages and damage' any relays are e!ipped %ith a connection &or a test cable' This permits !sing a test set to chec7 the relay calibration' The &ront co$er o& the relay is transparent, can be remo$ed &or access to the mechanism, and has pro$isions &or %ire and lead seals to pre$ent tampering by !na!thoriDed personnel'
Solid-state relays
olid state relay
ecently, solid+state electronic relays ha$e become more pop!lar' These relays can per&orm all the &!nctions that can be per&ormed by electromechanical relays and, beca!se o& the $ersatility o& electronic circ!itry and microprocessors, can pro$ide many &!nctions not pre$io!sly a$ailable' *n general, solid+state relays are smaller and more compact than their mechanical e!i$alents' /or e
Relay types There are literally h!ndreds o& di&&erent types o& relays' The catalog o& one man!&act!rer o& electromechanical relays lists 2.4 relays &or s%itchgear and system protection and control &!nctions' /or comple< systems %ith many $oltage le$els and interconnections o$er great distances, s!ch as !tility transmission and distrib!tion, relaying is an art to %hich some engineers de$ote their entire careers' /or more simple ind!strial and commercial distrib!tion, relay protection can be less elaborate, altho!gh proper selection and application are still $ery important' The most commonly !sed relays and de$ices are listed HERE in the Table by their American )ational tandards *nstit!te 5A)*6 de$ice+&!nction n!mber and description' These standard n!mbers are !sed in one+line and connection diagrams to designate the relays or other de$ices, sa$ing space and te
Overcurrent relays
epam protection relay
*n s%itchgear application, an o$erc!rrent relay !s!ally is !sed on each phase o& each circ!it brea7er and o&ten one additional o$erc!rrent relay is !sed &or gro!nd+&a!lt protection' Con$entional practice is to !se one instantaneo!s short+circ!it element and one in$erse+time o$erc!rrent element 5A)* "0E"16 &or each phase' *n the standard electromechanical relay, both elements &or one phase are combined in one relay case' The instantaneo!s element is a clapper or solenoid type and the in$erse+time element is an ind!ction+dis7 type' *n some solid+state relays, three instantaneo!s and three in$erse+time elements can be combined in a single relay case smaller than that o& one ind!ction+dis7 relay' ($erc!rrent relays respond only to c!rrent magnit!de, not to direction o& c!rrent &lo% or to $oltage' ost relays are designed to operate &rom the o!tp!t o& a standard ratio+type CT, %ith "A secondary c!rrent at rated primary c!rrent' A solid+state relay needs no additional po%er s!pply, obtaining the po%er &or its electronic circ!itry &rom the o!tp!t o& the CT s!pplying the relay'
(n the instantaneo!s element, only the pic7!p point can be set, %hich is the $al!e o& c!rrent at %hich the instantaneo!s element %ill act, %ith no intentional time delay, to close the trip circ!it o& the circ!it brea7er' The act!al time re!ired %ill decrease slightly as the magnit!de o& the c!rrent increases, &rom abo!t 0'02 sec ma
Setting the pickup point The standard o$erc!rrent relay is designed to operate &rom a ratio+type CT %ith a standard "A secondary o!tp!t' The o!tp!t o& the standard CT is "A at the rated nameplate primary c!rrent, and the o!tp!t is proportional to the primary c!rrent o$er a %ide range' /or e
!s!ally chosen &or o$erc!rrent protection' CTs are a$ailable ha$ing a %ide range o& primary ratings, %ith standard "A secondaries or %ith other secondary ratings, tapped secondaries, or m!ltiple secondaries' A !sable combination o& CT ratio and pic7!p coil can be &o!nd &or almost any desired primary pic7!p c!rrent and relay setting' The instantaneo!s trip 5de$ice "06 setting is also ad!stable' The setting is in pic7!p amperes, completely independent o& the pic7!p setting o& the in$erse+time element or, on some solid+state relays, in m!ltiples o& the in$erse+time pic7!p point' /or e
Setting the time dial /or any gi$en tap or pic7!p setting, the relay has a %hole &amily o& time+c!rrent c!r$es' The desired c!r$e is selected by rotating a dial or mo$ing a le$er' The time dial or le$er is calibrated in arbitrary n!mbers, bet%een minim!m and ma
Relay operation An electromechanical relay %ill pic7 !p and start to close its contacts %hen the c!rrent reaches the pic7!p $al!e' At the in$erse+time pic7!p c!rrent, the operating &orces are $ery lo% and timing acc!racy is poor' The relay timing is acc!rate at abo!t 1'" times pic7!p or more, and this is %here the time+c!rrent c!r$es start' This &act m!st be considered %hen selecting and setting the relay' When the relay contacts close, they can bo!nce, opening slightly and creating an arc that %ill b!rn and erode the contact s!r&aces' To pre$ent this, o$erc!rrent relays ha$e an integral a!
an in$erse+time relay and !p to .0 sec &or a $ery in$erse or e
CT and PT selection
c!rrent trans&ormer
*n selecting instr!ment trans&ormers &or relaying and metering, a n!mber o& &actors m!st be consideredB trans&ormer ratio, b!rden, acc!racy class, and ability to %ithstand a$ailable &a!lt c!rrents' CT ratio' CT g!idelines mentioned earlier are to ha$e rated secondary o!tp!t at 110 to 12"F o& e 0'3, 0'., or 1'2F' atio errors occ!r beca!se o& =*'s!p'2> heating losses' Phase+angle errors occ!r beca!se o& magnetiDing core losses' CTs are mar7ed %ith a dot or other polarity identi&ication on primary and secondary %indings so that at the instant c!rrent is entering the mar7ed primary terminal it is lea$ing the mar7ed secondary terminal' Polarity is not re!ired &or o$erc!rrent sensing b!t is important &or di&&erential relaying and many other relaying &!nctions' PT ratio' PT ratio selection is relati$ely simple' The PT sho!ld ha$e a ratio so that, at the rated primary $oltage, the secondary o!tp!t is 120' At $oltages more than 10F abo$e the rated primary $oltage, the PT %ill be s!bect to core sat!ration, prod!cing $oltage errors and e 0'3, 0'., or 1'2F' PT primary circ!its, and %here &easible PT secondary circ!its as %ell, sho!ld be &!sed' CTs and PTs sho!ld ha$e ade!ate capacity &or the b!rden to be ser$ed and s!&&icient acc!racy &or the &!nctions they are to per&orm' o%e$er, more b!rden or acc!racy than necessary %ill merely increase the cost o& the metering trans&ormers' olid+state relays !s!ally impose lo%er b!rdens than electromechanical relays' *D$or: %%%'ecm%eb'com Posted by ecsanyi on !nday, eptember 13, 200 at 4:13 pm | Technical Articles | Categories | !bmit Article
ANSI standards for protection devices "1,424 $ie%s
A)* /!nctions /or Protection e$ices
*n the design o& electrical po%er systems, the A)* tandard e$ice )!mbers denote %hat &eat!res a protecti$e de$ice s!pports 5s!ch as a relay or circ!it brea7er6' These types o& de$ices protect electrical systems and components &rom damage %hen an !n%anted e$ent occ!rs, s!ch as an electrical &a!lt' A)* n!mbers are !sed to identi&y the &!nctions o& med!im $oltage microprocessor de$ices' A)* &acilitates the de$elopment o& American )ational tandards 5A)6 by accrediting the proced!res o& standards de$eloping organiDations 5(s6' These gro!ps %or7 cooperati$ely to de$elop $ol!ntary national consens!s standards' Accreditation by A)* signi&ies that the proced!res !sed by the standards body in connection %ith the de$elopment o& American )ational tandards meet the *nstit!te9s essential re!irements &or openness, balance, consens!s and d!e process'
ANSI standards (protection) – index Current protection unctions
Recloser
=SI 5*851 – 'hase oerc"rrent
=SI $) – Reclose the circ"it :reaker a%ter tripping
=SI 5*=851= or 5*;851; – Earth %a"lt or sensitie earth %a"lt
Directional current protection
=SI 5*#0 – #reaker %ail"re
=SI !$ – Directional phase oerc"rrent
=SI 4! -=egatie se,"ence 8 "n:alance
=SI !$=8!$=C – Directional earth %a"lt
=SI 4)RMS – Thermal oerloa/
=SI !$=8!$=C type 1
Directional power protection unctions
=SI !$=8!$=C type 2
=SI 32' – Directional actie oerpo(er
=SI !$=8!$=C type 3
=SI 3284* – Directional reactie oerpo(er
Machine protection unctions
Voltage protection unctions
=SI 3$ – 'hase "n/erc"rrent
=SI 2$D – 'ositie se,"ence "n/eroltage
=SI 4&851@R814 – @ocke/ rotor 8 e6cessie starting time
=SI 2$R – Remanent "n/eroltage
=SI !! – Starts per ho"r
=SI 2$ – 'hase-to-phase "n/eroltage
=SI 5*851 – oltage-restraine/ oerc"rrent
=SI 5) – 'hase-to-phase oeroltage
=SI 2!8!3 – Thermostat #"chhol gas press"re temperat"re /etection
=SI 5)= – =e"tral oltage /isplacement
=SI 3&84)T – Temperat"re monitoring :y RTD
=SI 4$ – =egatie se,"ence oltage
Frequency protection unctions =SI &1 – .er%re,"ency =SI &1@ – +n/er%re,"ency =SI &1R – Rate o% change o% %re,"ency 7R.C.09
Current protection functions AS! "#$"% & Phase overcurrent Three+phase
protection
against
o$erloads
and
phase+to+phase
short+circ!its'
A)* inde< I
AS! "#$"% or "#'$"%' & Earth fault -arth &a!lt protection based on meas!red or calc!lated resid!al c!rrent $al!es:
A)* "0)E"1): resid!al c!rrent calc!lated or meas!red by 3 phase c!rrent sensors
A)* "0JE"1J: resid!al c!rrent meas!red directly by a speci&ic sensor
A)* inde< I
AS! "#B( & Breaker failure *& a brea7er &ails to be triggered by a tripping order, as detected by the non+e
sends
a
tripping
order
to
the
!pstream
or
adacent
brea7ers'
AS! )* & egative se+uence $ un,alance Protection against phase !nbalance, detected by the meas!rement o& negati$e se!ence c!rrent:
sensiti$e protection to detect 2+phase &a!lts at the ends o& long lines
protection o& e!ipment against temperat!re b!ild+!p, ca!sed by an !nbalanced po%er s!pply, phase in$ersion or loss o& phase, and against phase c!rrent !nbalance
A)* inde< I
AS! )R.S & Thermal overload Protection against thermal damage ca!sed by o$erloads on machines 5trans&ormers, motors or generators6' The thermal capacity !sed is calc!lated according to a mathematical model %hich ta7es into acco!nt:
c!rrent $al!es
ambient temperat!re
negati$e se!ence c!rrent, a ca!se o& motor rotor temperat!re rise
A)* inde< I
Recloser AS! / A!tomation de$ice !sed to limit do%n time a&ter tripping d!e to transient or semipermanent &a!lts on o$erhead lines' The recloser orders a!tomatic reclosing o& the brea7ing de$ice a&ter the time delay re!ired to restore the ins!lation has elapsed' ecloser operation is easy to adapt &or di&&erent operating modes by parameter setting' A)* inde< I
0irectional current protection AS! */$*/C type % AS! */ & 0irectional phase overcurrent Phase+to+phase short+circ!it protection, %ith selecti$e tripping according to &a!lt c!rrent direction' *t comprises a phase o$erc!rrent &!nction associated %ith direction detection, and pic7s !p i& the phase o$erc!rrent &!nction in the chosen
direction
5line
or
b!sbar6
is
acti$ated
&or
at
least
one
o&
the
3
phases'
A)* inde< I
AS! */$*/C & 0irectional earth fault -arth
&a!lt
protection,
%ith
selecti$e
tripping
according
to
&a!lt
c!rrent
3 types o& operation:
type 1: the protection &!nction !ses the proection o& the *0 $ector
type 2: the protection &!nction !ses the *0 $ector magnit!de %ith hal&+plane tripping Done
type 3: the protection &!nction !ses the *0 $ector magnit!de %ith ang!lar sector tripping Done
A)* inde< I
direction'
AS! */$*/C type % irectional earth &a!lt protection &or impedant, isolated or compensated ne!tralsystems, based on the proection o& meas!red
resid!al
c!rrent'
A)* inde< I
AS! */$*/C type 1 irectional o$erc!rrent protection &or impedance and solidly earthed systems, based on meas!red or calc!lated resid!al c!rrent' *t comprises an earth &a!lt &!nction associated %ith direction detection, and pic7s !p i& the earth &a!lt &!nction
in
the
chosen
direction
5line
or
b!sbar6
is
acti$ated'
A)* inde< I
AS! */$*/C type 2 irectional o$erc!rrent protection &or distrib!tion net%or7s in %hich the ne!tral earthing system $aries according to the operating mode, based on meas!red resid!al c!rrent' *t comprises an earth &a!lt &!nction associated %ith direction detection 5ang!lar sector tripping Done de&ined by 2 ad!stable angles6, and pic7s !p i& the earth &a!lt &!nction
in
the
chosen
direction
5line
or
b!sbar6
is
acti$ated'
A)* inde< I
0irectional po3er protection functions AS! 21P & 0irectional active overpo3er T%o+%ay protection based on calc!lated acti$e po %er, &or the &ollo%ing applications:
acti$e o$erpo%er protection to detect o$erloads and allo% load shedding
re$erse acti$e po%er protection:
against generators r!nning li7e motors %hen the generators cons!me acti$e po%er
against motors r!nning li7e generators %hen the motors s!pply acti$e po%er
A)* inde< I
AS! 214$)# & 0irectional reactive overpo3er T%o+%ay protection based on calc!lated reacti$e po%er to detect &ield loss on synchrono!s machines:
reacti$e o$erpo%er protection &or motors %hich cons!me more reacti$e po%er %ith &ield loss
re$erse reacti$e o$erpo%er protection &or generators %hich cons!me reacti$e po%er %ith &ield loss'
A)* inde< I
.achine protection functions AS! 2/ & Phase undercurrent Protection o& p!mps against the conse!ences o& a loss o& priming by the detection o& motor no+load operation' *t is sensiti$e to a minim!m o& c!rrent in phase 1, remains stable d!ring brea7er tripping and may be inhibited by a logic A)* inde< I
inp!t'
AS! )5$"%6R$%) & 6ocked rotor $ e7cessive starting time Protection o& motors against o$erheating ca!sed by: e
The reacceleration o& a motor that is not sh!t do%n, indicated by a logic inp!t, may be considered as starting' loc7ed rotor d!e to motor load 5e'g' cr!sher6:
in normal operation, a&ter a normal start
directly !pon starting, be&ore the detection o& e
A)* inde< I
AS! ** & Starts per hour Protection against motor o$erheating ca!sed by: too &re!ent starts: motor energiDing is inhibited %hen the ma
a&ter co!nting o&: starts per ho!r 5or ad!stable period6
consec!ti$e motor hot or cold starts 5reacceleration o& a motor that is not sh!t do%n, indicated by a
logic inp!t, may be co!nted as a start6 starts too close together in time: motor re+energiDing a&ter a sh!tdo%n is only allo%ed a&ter an ad!stable
%aiting time' A)* inde< I
AS! "#8$"%8 & 8oltage-restrained overcurrent Phase+to+phase short+circ!it protection, &or generators' The c!rrent tripping set point is $oltage+ad!sted in order to be sensiti$e to &a!lts close to the generator %hich ca!se $oltage drops and lo%ers the short+circ!it c!rrent' A)* inde< I
AS! 1*$*2 & Thermostat$Buchhol9 Protection o& trans&ormers against temperat!re rise and internal &a!lts $ia logic inp!ts lin7ed to de$ices integrated in the
trans&ormer'
A)* inde< I
AS! 25$)T & Temperature monitoring Protection that detects abnormal temperat!re b!ild+!p by meas!ring the temperat!re inside e!ipment &itted %ith sensors:
trans&ormer: protection o& primary and secondary %indings
motor and generator: protection o& stator %indings and bearings'
A)* inde< I
8oltage protection functions AS! 1/0 & Positive se+uence undervoltage Protection o& motors against &a!lty operation d!e to ins!&&icient or !nbalanced net%or7 $oltage, and detection o& re$erse
rotation
direction'
A)* inde< I
AS! 1/R & Remanent undervoltage Protection !sed to chec7 that remanent $oltage s!stained by rotating machines has been cleared be&ore allo%ing the b!sbar
s!pplying
the
machines
to
be
re+energiDed,
to
a$oid
electrical
and
mechanical
transients'
A)* inde< I
AS! 1/ & :ndervoltage Protection o& motors against $oltage sags or detection o& abnormally lo% net%or7 $oltage to trigger a!tomatic load shedding
or
Wor7s
so!rce
%ith
trans&er'
phase+to+phase
$oltage'
A)* inde< I
AS! " & Overvoltage etection o& abnormally high net%or7 $oltage or chec7ing &or s!&&icient $oltage to enable so!rce trans&er' Wor7s %ith phase+to+phase
or
phase+to+ne!tral
$oltage,
each
$oltage
being
monitored
separately'
A)* inde< I
AS! " & eutral voltage displacement etection
o&
ins!lation
&a!lts
by
meas!ring
resid!al
$oltage
in
isolated
ne!tral
systems'
A)* inde< I
AS! )/ & egative se+uence overvoltage Protection against phase !nbalance res!lting &rom phase in$ersion, !nbalanced s!pply or distant &a!lt, detected by the
meas!rement
o&
negati$e
se!ence
$oltage'
A)* inde< I
(re+uency protection functions AS! 5%; & Overfre+uency etection o& abnormally high &re!ency compared to the rated &re!ency, to monitor po%er s!pply !ality' A)* inde< I
AS! 5%6 & :nderfre+uency etection o& abnormally lo% &re!ency compared to the rated &re!ency, to monitor po%er s!pply !ality' The protection may be !sed &or o$erall tripping or load shedding' Protection stability is ens!red in the e$ent o& the loss o&
the main so!rce and presence o& remanent $oltage by a restraint in the e$ent o& a contin!o!s decrease o& the &re!ency,
%hich
is
acti$ated
by
parameter
setting'
A)* inde< I
AS! 5%R & Rate of change of fre+uency Protection &!nction !sed &or &ast disconnection o& a generator or load shedding control' ;ased on the calc!lation o& the &re!ency $ariation, it is insensiti$e to transient $oltage dist!rbances and there&ore more stable than a phase+shi&t protection &!nction' Disconnection *n installations %ith a!tonomo!s prod!ction means connected to a !tility, the ?rate o& change o& &re!ency@ protection &!nction is !sed to detect loss o& the main system in $ie% o& opening the incoming circ!it brea7er to:
protect the generators &rom a reconnection %itho!t chec7ing synchroniDation
a$oid s!pplying loads o!tside the installation'
Load
shedding
The ?rate o& change o& &re!ency@ protection &!nction is !sed &or load shedding in combination %ith the !nder&re!ency protection to:
either accelerate shedding in the e$ent o& a large o$erload
or inhibit shedding &ollo%ing a s!dden drop in &re!ency d!e to a problem that sho!ld not be sol$ed by shedding'
