US1726928A - Phase-sequence relay - Google Patents

Phase-sequence relay Download PDF

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US1726928A
US1726928A US685060A US68506024A US1726928A US 1726928 A US1726928 A US 1726928A US 685060 A US685060 A US 685060A US 68506024 A US68506024 A US 68506024A US 1726928 A US1726928 A US 1726928A
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relay
phase
circuit
sequence
currents
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US685060A
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Harvey P Sleeper
Charles Le G Fortescue
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CBS Corp
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Westinghouse Electric and Manufacturing Co
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R29/00Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
    • G01R29/18Indicating phase sequence; Indicating synchronism

Description

' Sprl3;j19z9'. A T AL" j 11,726,928
4PHASE SEQUENCE RELAY 1 Original Fied Jan. 8-I 1924 5 Sheets-Sheet l wlTNI-:Ssl-:s: vENToRs D l Har/Ve 5@ ev an@ 55:73@ am Char/SY ge@ fris cue ATTORNEY Sept.' 3, 192 9.
Original Filed.Jan.
5 Sheets-Sheet 3 K x W f l V I l 1 Il I .l
l l' l l l i I L/ "f L il 'IQ f 1 l l 1 l l l H\\ l l x 1 ii i; :1 l Il 11 f Y wl 23 l? l1 1| i l l 1' ll AI3 ag W-TNESSES:
INVENTORS Har v@ S/efper and Sept. 3, 1929,
H. P. sLEEPx-:R ET Al. Y 1,726,928
PHASE SEQUENCE RELAY Y Original Filed Jan. 8v, 1924v 5 Sheets-Sheet 4 Bm; AIE
` WITNESSES: INVENTORS a Ham/eff? Shaper and CCR W f Char/e5 L. /L/eScL/e ATTORNEY H. P. sLEEPER n'ET Al. 1,726,928'
PHASE SEQUENCE RELAY original Filed Jan. 8, 1924 Y 5 sheets-Sheet' 5 ATTORNEY Patented Sept. 3, 1929.`
UNITED STATES PATENT oirplclgp HARVEY P. SLEEPER, OF NEWARK, NEW JERSEY, ANDl CHARLES LE G. FORTESCUE,
OF PITTSBURGH, PENNSYLVANIA, ASSIGNORS TO WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATLON OF PENNSYLVANIA.
' PHASE- SEQUENQE RELAY.
Application sied January s; 1924, seriar Na'esspco. Renewenay 9, 12529.
Our invention relates to electrical protective devices and more particularly-to phases'equence relays.
One object of our invention i's to provide a phase-sequence relay that shall be adapted to protect a polyphase circuit under 'conditions of overload-or short-circuit, phase unbalance, open-phase and phase reversal.
` Another object of our invention is .tol provide a. time element relay t-hat shall operate only in response to the. positive or negative phase-sequence component of the currents in a polyphase circui Still another object'of ou'r invention is to providea unitary relay that shallfc'mbine the functions formerly secured only by'the employment of a plurality ofseparate relay structures. .Y
A further object of our invention is topro- Vide a relay of improved construction that distinguishes between positive and negative phase-sequence components of current.`
Heretofore, 1t has been necessary to provlde relays in each phase of a polyphase circuit in order to protect the circuit against conditions of overload and short-circuit, phase-reversal, open phase o rphase' unbalance. Such instruments are expensive andthe number 'of such instruments required to .adequately protect any polyphase circuit from the many interruptions to service towhich such lines lare subjected, is excessive. With our improved relay, the above. enumerated protective 'features are obtained. by the use of a single instrument that operates in response to an abnormal positive phase-'sequence component orl negative phase-sequence component of current caused by a fault, irrespectiveof the phase or phases involved in the fault.
Inour relay, an impedance network is provided of such character that two branches thereof are traversed by currents proportional to the positive andl the negative phasesequence components of the currents in the phaseconductors' of an associated polyphase circuit under all conditions. A relay is connected in each of the respective branches of the network and is energized in accordance with the magnitude of the corresponding symmetrical component, the.pos1tive phasesequence .component being a measure of the overload and the negativephase-sequence component being a measure of the-unbalance Fig. 4 is a-diagrammatic view of apparatus' and circuits embodying our invention.
. Fig. 5 is a diagrammatic view of a different arrangement of circuits and apparatus.
Fig. 6 is a vector dia ram of the currents traversing our relay under normal condition of phase balance.
Figs. 7 and 8 are-.vector diagrams of the currents traversing our relay under conditions of phase reversal.
Figs. 9 to 11, inclusive, are vector diagrams of the currents traversing our relay under conditions of open phase.
Fig. 12 is a vector diagram of a threephase unbalance; and
' Fig'. 13 Ais a diagrammatic view of circuits and apparatus showing our relay used in combination with a grounded 'polyphase circuit. Referring-to Fig. 4, `our invention comprises, in general, a unitary relay structure 10 'that embodies `a resistor 11, reactors 12 and 13, andthe winding 14 of a relay.` These parts are connected in an impedance network the reactor 12 and the windings of the relay 14 are equal.- The reactor l2 may take the form of a winding 15 of a second relay, as shown in Fig. 5. The relays comprising the windings 14 and 15 may be connected to a .suitable circuit interrupter or other electrical devices (not shown) for controlling the. polyphase circuit 18. Y
Referring to Figs. 1 and 2, the'relay com- .opposite upper corners of the base member 21, Between `them are'disposed a plurality of spools having coils thereon constituting the resistor 11. yOn' thejlower half of the base 21 is mounted a relay 25that comprises the Winding 14, a'.pivoted armature member .19 controlled thereby a stationary Contact member 27 and a movable contact member 28 secured to' thearmature member 19 and controlled b y the current traversing the winding 14. Damping magnets 2O arepro vided for retarding the movement of the armature member 19. The relay 25 'is of the overload induction type'having an inverse or definite time-element characteristic Vand since its functions 'and details of operation are well known Ain the art, a description thereof is believed toF` be unnecessary, except in so far as 'it is necessary to complete the combination with the remaining component parts of my invention.
Referring to Figs. 4 and 6, under conditions of current balance in the circuit 18, the currents traversing the several. phases A, B and C are normally 120 degrees apart.
y The current from the -current transformer 16 that is connected in phase A is delivered to the impedance network between the arms 1l, 12 and 13,`14,"while the `current from the current transformer 17, that `is connected in -phase B, is delivered-to the impedance.
network between the arms 11, 14 and l2,
No current transformer is placed in the phase C for the reason that any disturbance between phase C and either of the otherphases A or B will be recorded by an unbalance in the affected phases.
Underbalanced conditions, the current from the phase A traverses the parallel circuits comprising resistor 11 and winding 14,
j and reactor 12 and reactor 13. By reason of the relation of the resistor 11 to the resistance and reactance of the reactor 13, which is of the same absoute impedance, 'a current proportional to 'the positive phase-sequence component traverses the reactor'12 and a current'proportional to the negative phase-sequence component traverses the relay wind- .ing 14. As is shown in Fig. 5, the fact that both positive and negative phase-sequence components traverse the networkv may be taken advantage of by having the reactor 12 comprise the Winding 15 of a second relay 26 responsive to the magnitude of the positive phase-sequence component, thereby providing overload and short-circuit protection to the 'circuit 18.
Referring to Fig. 6, the currents A14 and B11 derived from phases A and B are norinally egual in amount and opposite in direction under balanced conditions, thereby vequalizing one anotherwith the result that no current traverses the winding 14 of thev relay 25. Under' unbalanced conditions, a currentproportional to the negative phasesequence componenttrarerses said winding.
Asshown in Fig. 44, the current AnlagsV the current A11 by an angle of 60 un'der balanced conditions hecauseof the greater reactance of the branch 13 with respect to the branch. 11 of the network. The sum of the currents A12 and A11 is equal to the current in-the phase conductor A (see Fig. 6). In a similar manner, the current B12 lead the curr'ent B11 by an angle of 60 under balanced conditions and the. sum of the currents B12 and B14 is equa-l to the current 1n the phase,
is proportional under all conditions to the positivephase-sequence component of the c urrents inthe distribution circuit and lthe sum of the 4currents A1,1 and B11, which traverses the branch 14 of the network, is proportional to negative phase-sequence component. Under `balanced current conditions, which are shown in Fig. (3, the positive component is maximum and the negative component is zero. Various other conditions are `illustrated-in Figs. 7 to 12.
Referring to Fig. 7, upon the occurrence of a reversal between thefphases A and B,'the currents A12 and B12 are substantially'equal and opposite in direct-ion with thc result that substantially no current traverses the reactor 12 whilethe sum of the currents ,A11 and B14 traversingthe winding 14 becomes of an ap.- preciable value with theresult that the relay 25 is operated to control any desired mechanism connected with the circuit 18, such as a circuit interrupter (not shown).
Similarly,.upon the reversal of phases B 'and C, the positive phase-sequence components ate the negative phase-sequence relay 25. By comparing Figs. 7 and 8, it .will be seen that the vector. diagrams are identical except for the fact that the 'relatively angular displacement of similar components is different.
Referring to Fig. 9, there is shown a vector diagram of the current traversing the relay when phase C is open. In this case, the currents Al and B are-equal and oppositein di- 'either event. a negative phase-sequence current of an appreciable value traverses the of curentbecome effective to operwinding 14 of the relay 25 that is operated.
Referring to Fig. 12,` a condition of three-- phase unbalance is shownwherein the currents A, B and C are displaced at other lthan- 120 degrees. It will thus be seen that the vresulting nevative phase-sequence current 14 y has-an appreciable value and, therefore, op-' crates the relay 25.
Referring to Fig, 13, if the phase-sequence relay is to operate on af distributing system having a neutral point grounded as at 31 and 32, it may be undesirable to have it influenced by the zero phase-sequence component of eurrent. in which case the disposition of the current transformers may be such as to eliminate the zero phase-sequence component from the circuits of the relay. This result is securedby providing the current transformers'33 and 34, correspondingto the relays 16 and 17, of
y Fig. 4, respectively, with two primary windeliminated therein. .The relay is therebyren-- dered independent of current in the grounded circuit-which' is the zero phase-sequence c urrent and provlsion 1s made for protection against groundsby interposing a suitable 4instrument 39 in the` grounding lead for op-- erating o n a predetermined value' ofgroundcurrent. L
It will thus be seen that we have provided a relay that is responsive to'the value of the positive and negative phase-sequencel cur.` rents'in the polyphase circuit.' We have also provided a singleunitary relay that is responsive to any Afault that 4produces y an un'- balanced current condition, irrespective f.v the phase or phases affected thereby. Since the positive phase-sequence current is ameasure of the overload or short-circuit ,conditions in the circuit'and sincethe negative phasesequence current isa measure of phase unbalance, phase reversal and open-phase condi-l tions, two relays embodying'r our invention will afford all the desired protection for a Apolyphase electrical circuit. ,One ofv the' ad;
vantages of our invention, as will' appear, is that a great saving 1n the use of' 1current transformers, as well asof relays, 1s effected' .while still obtaining complete circuit protection.
Furthermore, thenegative phase-sequence relay with a time-element or retarded opera.-
tion has an important application inlarge distribution systems in which t-he unbalance of the system currents upon the occurrence of a fault is greater in certain portions of thesystemA than in other portions. Since thedegree of-energization of the relay depends upon the magnitude of the negative phase-sequence quantity o r, in other'words, upon the amount of unbalance of the system,`tlie time of operation of the relay' varies in accordance with its relatiOntOtlie'auIt. In this manner, selectivedisconnection ofthe faulty portion ofthe distribution system may be obtained.
We do not wish to be restricted to the specific circuit connections or arrangement of .parts herein set forth, as 'various modifications thereof may be effected without departing from the spirit and scope of-our invention. Ve dcsire,lther'vefore, that only such limitations shall be imposed as are indicated vin the appended claims.
lVe claim as our invention:
1.' Anelectrical protective device comprising an impedance network consisting of a winding of a relay, a resistor and a pair of reactors, 'one of said reactors having the same resistance and reactance as the winding of the relay. l
2. An electrical protective device comprisin'g al quadrilateral impedance network consisting of a Windingof a relay, aresistor and i a pair of reactors, one of said`reactors having the s'ame resistance and reactance as the winding ofthe relay, being disposed on an opposite side of the impedance network relative to the winding of the relay. 3. An electrical protective device comprising a quadrilateral impedance network consisting of aavinding of a relay, a resistor, and
a. pair of reactors, one of said reactors ha ving the 'same resistancev and reactance as the winding of the relay, .and being disposed on an opposite side of the impedance network relative to the v vindingof the relay, said reactor constituting an element of a second relay.
4. The combination withl a'polyphase electrical eircnit, a relay and a plurality of transformers connected to said circuit, of an elec- .trical protective device comprising a quadrilateral impedance network energ-ized from `said transformers comprising a winding of Qthe relay, a-'reslstor and a pair 'of reactors, the,
winding of said relayand a reactor of equal resistance and reactance constituting opposite sides of the impedance nctworln v5.- The combination with a polyphase electrical circuit, arelay and 'a' plurality of transformersconnected to-said circuit, of an electrical protective device comprising an impedance. network in the form of a bridge having opposite points connected to each of the respectivetransformers consisting of a winding of the relay, a resistor and a pair of reactors, the winding of said relay and a reactor of equal resistance and reactance constituting opposite arms of the impedance network, whereby said relayis caused'to operate only in -response'to one' phase-sequence component of the current in the polyphase circuit.
trical circuit,
the winding of said relay `ance networkengrgized winding ofeach of l network causes the 6. The combination with a polyphase elecva relayand two transformers connected in separate phases of said circuit, of an electrical protective device .comprising an impedance bridge network energized from vsaid transformers consisting of a winding of pai'r of reactors,l
the relay, a resistor and a and a reactor of equal resistance and reactance constituting opposite arms of"'tlie'impedance network whereby the relay is caused to-operate in ac-` cordance with the negative-pliasc-sequence component of the current traversing the circuit which is a measure of the conditions of open phase, phase imbalance, unsymmet'rical short circuit, and phase reversal in said circuit. c 'i 7. The combination with a polyphase electrical circuit, a relay and a. plurality of transormers connected to said circuit, of an electrical protective device comprising a quadrilateral impedance network. energized from said transformers consisting of a winding of the relay, a resistor and a pair of reactors, the
winding of said relay and a reactor of equal resistance andreactance constituting opposite arms of the impedance networkand the resistor and other reactor constituting the other arms'of the network and having such relative characteristics that the relay is caused to operate under conditions of phase f unbalance in said circuit.
8. The combination with a polyphase electrical circuit, a relay and two transformers connected to'separate phases of saidcircuit, of an electrical protect-ive device comprising an impedance bridge network ,having opposite points connected to each of the respective transformers consisting of a winding of the relay, a resistor and a pair of winding of saidrela'y and a reactor of equal resistance and react-ance constituting opposite arms of the impedance network `and the resistor and the other reactor constituting the other arms of the network and having. suchrelative characteristics that the relay is caused to operate under open-phase conditions insaid circuit. .I i
9. The combination with a polyphase electrical circuit, a relay and two transformers connected to separate phases of saidcircuit, 0f an electrical protective device comprising an impedance bridge network having opposite points connected to each of the' respective transformers, a winding of the relay forming one-of the branches of said network.
10.- The combination with a polyphase electrical circuit, a plurality of connected transformers, and a pair of-relays, `of an impedfro'm said transformers consisting of a resistor. a reactor .and a said relays, whereby said operation of one of said relays upon the occurrence of negative-phasereactors, the v sequence currents in said circuit and said network causes the operation of the other relay under conditions of excessive positive phasesequence currents in said circuit. 11. The combination with a polyphase electrical circuit, a relay and a plurality of transformers connected to said circuit, of an electrical protective device comprising an impedance formers consisting of. a winding of the relay, a resistor anda pair of reactors, the winding of said relay and a reactor of equal resistance currents.
13. An electrical ing an impedance bridge network for segregating negative phase-sequence currents from' positive phase-sequence currents and means for selectively responding to currents of a predetermined'phasesequence.
14. An electrical device comprising a quadrilateral bridge network responsive to both positive and negative sequence currents inde-,
pendent of-sequence voltages for segregating and reactance constituting' opposite arms of protective device comprisbranch a member operative in response to positive phase-sequence' network energized from said transsov protective device compristhe negative sequence currents from the positive sequence currents, and means selectively responsive to currents ,of predetermined phase sequence for trical device.
15. The combination with afpolyphase electrical circuit, a pair of relays, means, comprising a plurality of current transformers, for
eliminating zero sequence currents from the pair of relays, of -another relay ,responsive to zero sequence currents alone, and an impedance bridge network energized from the' transformers consisting'of a resistor, a reactor and a lwinding of each'of said pair of relays,
' whereby said vbridge networkcauses the operation of one of said pair of relays upon the occurrence o f'negative sequence c urrents in said circuit Vand said bri'dge networkcauses the'operation ofthe other of said pair of relays in response to excess positive sequence currents in said circuit.-
16. The' combination with a polyphase elecinluencing another elecizo trlcal circuit,'of means for separating out or segregating both the positive and the negative sequence currents from the zero sequence currents in the circuit, means responsive to the last-named means and' comprising a quadrilateral bridge network for segregating the negative sequence currents from the positive sequence currents, and means selectively and l separately responsive to predetermined sephase-sequence quantities of said circuit, and quence currents for inuenoingvanother eleomeans for eliminating the zero phasesetrioal device. quenee quantities from said control means. 10
17. In combination With an electrical cir- In testimony whereof, .We have hereunto 5 cuit having acircuitinterrupter therein, of subscribed our names.
means for controlling the operation of'said HARVEY P. SLEEPER. A v interrupter including means responsive tov CHARLES LE G7 FORTESCUE.
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2897407A (en) * 1953-11-03 1959-07-28 Gen Electric Negative-phase-sequence responsive apparatus
US3172012A (en) * 1960-02-04 1965-03-02 Burns N Gafford Protective relay for polyphase machines responsive solely to positive and negative sequence currents
US3258648A (en) * 1961-03-11 1966-06-28 Apparatus responsive to overload and unbalance in a three phase electrical supply

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2897407A (en) * 1953-11-03 1959-07-28 Gen Electric Negative-phase-sequence responsive apparatus
US3172012A (en) * 1960-02-04 1965-03-02 Burns N Gafford Protective relay for polyphase machines responsive solely to positive and negative sequence currents
US3258648A (en) * 1961-03-11 1966-06-28 Apparatus responsive to overload and unbalance in a three phase electrical supply

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