US2426062A - Distance-type relay with currentcompensated voltage restraint - Google Patents

Description

1947- w. K. SONNEMANN 2,426,062

DISTANCE-TYPE RELAY WITH CURRENT-COMPENSATED VOLTAGE RE STRAINT Filed Feb. 16, 1945 WITNESSES: Fl x3. INVENTOR m M j W1 [Ham [1. Sonnemcmn. 72w 4. W BY ATTORN EY Patented Aug. 19, 1947 COMPENSATE-D VOLT G ,RESTRAINT William K. Sonnemann, Roselle Park, N. J., .as-

signor to Westinghouse Electric =CQ 3DQration, ,East Pittsburgh, Pa., acorppration of -lfennsyl- Vania Application February 16, 1945, Serial'No. 578,263

. 4 Claims. (01.1757234) 1 My invention relates toadjustable distancetype relays having modified impedance charac teristics which can be readily adjusted. ThisI'Ellay isadapted to be utiliz ed on alternating-cur- ,2 Justine, thelenet of. the radius, of), the repentecircle, witholltssubstantially aftectingthe position of the. centers of, the, circle, while the adjustmer ts, of thevariab-le resistance and the varia le rent lines for the purpose of detecting faults 5 reactancerrespectively ,controlthie R andiXicothereon. ordinates of th center o'f 'the respQnSe circle, Recent trends-in the .art of high-speed relaywithoutfrnateri'ally affecting its radius; ing for transmission lines, and more particularly A 'further cbject' "of myinvention relates tothe for the so-called long transmission lines, ,haVe provision of means forbbthmeversing and adindicated the need for high-speed impedance rejustingthe magnitude. of both the inL-phase and lays having modified characteristics, that is, havthe outer-phase components of, the currentereing predetermined directional, as well as impedsponsive compensator, independently of veach ance, characteristics. The response-circle, repother, so that the .centercofsthe response-circle resentin the locus of the line-impedance values canlbe .readilylocated in anyposition in anyone at the balance-point. of such arelay, when plotof thetfour. quadrants. ted on rectangular coordinates of the une-resistswiththeforcgo n and, other lobiectsinuvi ance R and the line-reactance X, will have a cenmy invention cc nsists in the apparatus, ombinater which is, in general, displaced from the origin ,tions, systems, parts, and methods er 'nafter and adjustable in position, anda radius which describedanid claimed, and illustrated-inlthefa'cis also adjustable in magnitude. If these adjustt'om aaymggdrawmg, he in= ments are properly calibrated, and of such nali igureglfisQaldiagrammaticflvicwp .P mtl an ture that they can, readily be made by the user apparatus ilIstrating the 'c'ohne lfo'r'iia of the relay, they thusafiord a means whereby phase-A}. phaSe aultfrelayembodyi g'iiryi yem the particular exigencies of each protective sysuse, tem may be properly adjusted to th transmis- @Fig. 2 is a response-circle, diagram illustrating sion system to which it applies. the inve tio a d An object of my invention is to provide a new "Fig. '3 is a diagrammatic view of parts of the and improved means whereby these adjustments energizing circuits of. aTmodified form. of embodimay be separately and independently made, so mentof my invention. that a calibrated adjustment may be made as to .In ,Fig. 1, ;I,have; i11ust 3ated.,n 1y inyentiomas the circle-radius, or as to either the R or X 00- beingapplied to the protection of, athree-phase ordinates of the centerof the circle, without subtransmission line '5, the three phases of which stantially changing the other two adjustments are ,indicatedat, A, B and C. The line 5 is."conor settings; or the position of the center may be nectcd ,togavbus, B. My invention is sho wn, ,hy fixed by independentlyadjusting the angle of the wayjfofp illus tration, as ap 'd we, phaseriault line along which the center is .displacedfrom reIayLshQWn. at h fpr .lTESPOQdin jl gp fi the origin, and theamount or distance of such faults, ,or, ,more I accurately, faults vi ng displacementof thelcenter from the origin. phases Afand Bot the transmission system. l :A- further object of my invention is to provide one sll qhlelay .is illustrated, as Ish relays for a rela of the; differential type, that is, a relay 40 but ,asinglephase. j Ordinarily there lwould be having an operating force and a restraining sfeyeral such rela'ys,,one f ore'ach phase, andelso force, and means for causing theoperating force vg TQl ndrfaultfrelay, or else some special phaseto be dependent solelyupon the magnitude of the sequence energiza tion-means wherebya single line-current,but variable or adjustable incl-ts rerelay is madeto respond to a plurality ofjtypes sponse, while causing the restraining force to be of faults on different phases, allofwhich things responsive to a current-compensated linewoltare Well known in the art. M age, which is equal ,to the vectorial sum of an al- The relay 1. sin nt fidstq e re re enta ternating-current functionof a line-derived vo1t symbolic of any d e i l typ 01 r by a a t ngu o of a in hic ymen-Meier.White-ha te ;wantin derived current times a variable resist nce} o fo ecnp dy a r s ra nin f xc rh p i sle uiva entvanaana te n ti e-cu'r t functicular differential-type relay 1 which is'shojwn tionof alinederived current .timesaivaigiable rein Fig. 1 is of the balanced-beam typ having actance, or its equivalent. The energizationof an operat ng C01 0 W nd n liW p the relayis suchthat the adjustability of the e p phase restraining coils or windings 9 and l 0. The crating-force i'esp onse afiords a means for admagnetizing currents in the two restraint-windings 9 and ID are approximately 90 out of phase with each other, this dephasing being accomplished by means of a capacitor C in series with the winding ID, the two windings 9 and It] being energized in parallel from a common energizingcircuit having a voltage ER. This is a well-known means for obtaining a substantially steady or non-pulsatory restraining-force for insuring the proper operation of the relay.

The relay 1 is illustrated as having a single make-contact II on the operating end of the beam. The relaying circuits which are controlled by the make-contact H are not shown, as my present invention relates primarily to the means for controlling the closure of these contacts, rather than the relaying system which is chosen to make use of the relay-contacts in the proper protection of the transmission line 5.

The operating coil 8 of the relay is energized by means of a line-derived current i which is furnished by any suitable means such as linecurrent transformers 12. The restraining windings 9 and ID are energized from a current-compensated line-derived voltage he. The restraint voltage ER is obtained from a line-derived voltage which is derived by any suitable means such as a potential transformer l3, in series with a compensator comprising an impedance Z which is traversed by a function of the line-current, produced by means of an auxiliary current-transformer l4 connected in series with the currentsupply for the operating coil 8. The auxiliary current-transformer I4 has a primary-winding tap K1, or other ratio-adjustment means whereby an adjustable current K11 is supplied to the impedance Z1. The impedance 21 consists of a variable resistance R1 in series with a variable reactance X1, the latter being indicated as an inductive reactance, although it could be either inductive or capacitive. The current-compensated voltage-responsive energizing-circuit for producing the restraint-voltage Ea thus comprises, in series-circuit relation, the line-derived voltage-source E, the in-phase compensatorcomponent KiiRi, and the out-of-phase compensator-component 7'K1'IX1. The combined impedances of the split-phase restraint-windings 9 and ID are indicated as Zn, and the total restraint-winding magnetizing-current is indicated at in.

In Fig. 1, the magnetizing force or ampereturns on the operating coil 8 are adjustable by means of a tap K on the operating coil 8, or by any equivalent means, so that the operating force is responsive to the magnitude of the quantity KI. The operating and restraining forces of my relay may be responsive to either the first power, or the square, or any other power, of the respective magnetic fluxes on the two sides of the relay, or the two ends of the balanced beam of the relay.

If the line-current i, as applied to the relay 1, lags the line-voltage E by an angle 0, the linecurrent may be written If the restraint-voltage ER is taken as the ampere-turns on the restraint-side of the differential relay I, and if the current KI is taken as the ampere-turns on the operating side of the relay, then the balance-point condition occurs when ER=KI'LB (3) E-KJZ',

R RZR Zl+ZR ZR (4) Equating Equations 3 and 4, substituting E l'ZZ from Equation 2, and rearranging the terms, we find whence the locus of the line-impedance Z'=R+9'X, up to the fault, that is, at the balance-point of the relay 1, is found to be If 21/28, is negligibly small, as compared to unity, Equation 6 becomes, approximately,

which is a circle, as shown at H5 in Fig. 2, having a center (shown at C) which is displaced from the origin 0 by a distance (impedanceohms) The distance by which the center C is displaced from the origin 0 is ZO=K1\/ %+Xi 3 In Fig. 2, the response-circle I5 is plotted on rectangular coordinates representing the line-resistance R and the line-reactance X, or y'X. If P is any point in the circle I5, the line OP=Z represents the line-impedance at the balancepoint of the relay. The relay will respond for any line-impedances terminating within the circle !5. For line-impedances terminating outside of the circle 15, the restraining force of the relay exceeds the operating force, and the relay will not respond.

Equations '7, 8 and 9 show that the impedance Z0 of the line-ohms up to the center C of the circle I5 is substantially equal to K121, while the circle-radius GP, or Q0, is substantially equal to the variable quantity or ratio K. These variables are all substantially independent of each other.

The complete expression for the radius Q0 of the circle involves the expression (l-l-Z'1/Z'e), which is not quite equal to'unity. In any practical relay, the ratio Zi/ZR will actually be rather small compared to unity. and it can be made as small as may be desired. at the expense of a somewhat increased burden on the current-transformers i2. In a practical relay-design for 115 volts. 60 cycles. the restraint-circuit impedance ZR is of the order of 12,000 ohms, whereas an impedance of the order or" 200 or 360 ohms will be ample for Z1 when used with a suitable ratio K1. In the restraint-voltage circuit, the effect of Z1 in producing a burden is proportional to KiIZi, but in the current-circuit of the line-current transformers E2, the effect of Z1 in producing an extra burden is proportional to K1 I Z1. It follows that an increase in Z1, accompanied by a corresponding decrease in K1, retains the same effect in the voltage-circuit, but reduces the burden in the current-circuit. The impedance-values which I have suggested give satisfactory operation, with an acceptable burden on the current-transformers l 2, and with a negligible error in the length of the circle-radius, even though the adjustable impedance Z1 is changed from zero to its maximum value of 200 or 309 ohms.

There are several ways in which my invention can be utilized. Splitting the variable impedance Z1 into its in-phase and out-of-phase components R1 and X1, it will be seen, from Equations 7 and 8, that the coordinates of the center C of the response-circle are as stated in Equations 10 and 11, the R-coordinate being K1R1, and the X-coordinate being K1X1. Thus, leaving the adjustment K1 alone, on the auxiliary current-transformer M, the resistance R1 may be varied or adjusted, in order to fix the R-coordinate R0 of the center, while the inductance X1 may be adjusted in order to independently fix the X-coordinate X0 of the center. It will be readily seen that these two adjustments could be calibrated directly in line-ohms.

The radius Q0 of the circle l5 can be controlled by varying the relative magnitudes of the responses of the operatin force and the restraining force of the relay, with respect to the operating flux and the restraining flux, respectively. Thus, in Equation 3, the variable K may be either retained, as K, on the right-hand side of the equation, or it may be put in the left-hand side of the equation as l/K. In the particular type of relay shown in Fig. 1, it is more convenient to adjust the ratio K on the operating end of the relay, than it is to adjust the ratio l/K on the restraint-end thereof, but it will be readily understood that either adjustment may be made. This provides an easy way of independently adjusting the radius of the response-circle 15, without affecting any other characteristic of the relay, so that this adjustment can be calibrated directly in line-ohms, if desired.

There are other ways in which my novel adjustment-means may be utilized. Thus, as shown by Equation 13, the center-displacement is simply the distance Z0, which can be controlled by varying the ratio K1 of the auxiliary current-transformer l4, while keeping the magnitude of the impedance Z1 constant. The angle So of the center-line Z0 can then be changed, as indicated by Equation 12, by changingthe phase-angle of the impedance Z1, without changing its magnitude Z1.

In the foregoing discussion and explanation of my invention, I have described my invention as being responsive to any suitable line-derivedcurrent l, and any suitable line-derived voltage E. I have intended that this discussion should be perfectly general. In the particular relay which is indicated in Fig. l, the response is to the delta line-current IAe=iAIs, and the delta line-Voltage EAB. It is to be understood, however, that any other line derived current and line-derived voltage might have been utilized.

Also, while I have shown specific illustrative adjustment-means in Fig. 1, any equivalent adjustment-devices might be utilized.

In some cases, it may be desirable that the effects of the variable resistance R1 and the variable reactance X1 shall be separately adjustable in sign or direction as well as in magnitude, each independently of the other, so that the circle-- center C may be readily located in any one of the four quadrants of the rectangular systemof the coordinates R and X.

Thus, in Fig. 3, I have shown the inductance Xi as a fixed secondary coil X1 of a mutual'reactance M, having a primary winding I 6. The line-derived current I is circulated through the primary winding iii of the mutual reactor M, and also through the primary winding I 1 of a transformer E3, the secondary winding of which is connected across the resistor R1. The primary'windings l6 and ll of the mutual reactor M and the transformer it are provided with tap-blocks or other tap-changing means for providing the adjustable taps it and 26 on the winding l6, and the adjustable taps 2i and 22 on the winding I'I, so that the direction or current-flow can be changed, at will, in either one of these windings, as well as the effective number of turns. resistor R1 in Fig. 3 and the reactor secondary X1 in Fig. 3 may both be constant in magnitude, the impedance eiTects, or the effective impedances, of these elements may be changedyboth in magnitude and in sign, by proper choice or adjustment of the adjustable taps 19, 20, 2| and 22.

In Fig. 3, a network is shown-for utilizing any voltage-source E, which is applied to the net workterminals 23 and 24, and for utilizingany current-source I, which is applied to the networkterminals 25 and 26. The network produces a current-compensated output-voltage ER, which is produced across the output-terminals 21 and 23 of the network, while the current-circuit of the network is opened at the output-terminals 29 and to, so that an operating current Io may be circulated in any differentially responsive relaymechanism, which is broadly indicated by the rectangle 3| in Fig. 3.

The rectangle 3| in Fig. 3 i intended to be representative of any relay circuit, or combination, or means, which compares magnitudes of two electrical quantities, which have been indicated, for convenience in reference, as an operating current In and a restraining voltage ER, although both quantities might be voltages, or both currents, or any other electrical quantity. The relay 3! has a relay-contact which is symbolically indicated at 32 in Fig. 3, corresponding to the relay-contact I I in Fig. 1.

While I have shown my invention in two different illustrative forms of embodiment, I wish it to be understood that my invention is susceptible of considerable modification, by way of a1- terations, substitutions, additions, and subtractions, without departing from some of the essential features of the invention. I desire, therefore, that the appended claims shall be accorded Thus, while the the broadest construction consistent with their language.

I claim as my invention:

1. An adjustable distance-type relay having an operating-circuit means, for producing an operating force responsive to the amount of energization of the operating circuit; a restraint-circuit means, for producing a restraining force responsive to the amount of energization of the restraint circuit; current-responsive energizingcircuit means, for energizing the operating-circuit means so as to be exclusively responsive to a linederived current; current-compensated voltageresponsive energizing-circuit means, including a resistance, an inductance, a reversible and variable-ratio transformer-means associated with said resistance, and a separate reversible and variableratio means associated with said inductance, for energizing the restraint-circuit means in response to the vectorial sum of an alternating-current function of a line-derived voltage, an alternatingcurrent function of a line-derived current times said resistance, and an alternating-current function of a line-derived current times said reactance; and means for varying the relative magnitudes of the responses of the operating force and the restraining force.

2. An adjustable distance-type relay having an operating-circuit means, for producing an operating force responsive to the amount of encrgization of the operating circuit; a restraint-circuit means, for producing a restraining force responsive to the amount of'energization of the restraint circuit; current-responsive energizing-circuit means, for energizing the operating-circuit means so as to be exclusively responsive to a line-de rived current; current-compensated voltage-responsive energizing-circuit means, including a resistance, an inductance, a reversible and variable-ratio transformer-means associated with said resistance, and a separate reversible and variable-ratio means associated with said inductance, for energizing the restraint-circuit means in response to the vectorial sum of an alternatingcurrent function of a line-derived voltage, an alternating-current function of a line-derived current times said resistance, and an alternatingcurrent function of a line-derived current times said reactance; and means for varying the magnitude of the response of the operating force.

3. An adjustable distance-type relay having an operating-circuit means, for producing an operating i'orce responsive to the amount of energization of the operating circuit; a restraint-circuit means, for producing a restraining force responsive to the amount of energization of the restraint circuit; current-responsive energizingcircuit means, for energizing the operating-circuit means so as to be exclusively responsive to a linederived current; current-compensated voltageresponsive energizing-circuit means for energizing the restraint-circuit means, including an alternating-current source of a line-derived voltage, a serially connected resistance, and a serially connected inductance, a reversible and variableratio transformer-means associated with said resistance, a separate reversible and variable-ratio means associated with said inductance, and a variable alternating-current source of a line-derived current associated with said reversible and variable-ratio means for energizing both said resistance and said inductance; and means for varying the relative magnitudes of the responses of the operating force and the restraining force.

4. An adjustable distance-type relay having an operating-circuit means, for producing an operating force responsive to the amount of energization of the operating circuit; a restraint-cincuit means, for producing a restraining force responsive to the amount or energization of the restraint circuit; current-responsive energizingcircuit means, for energizing the operating-circuit means so as to be exclusively responsive to a line-- derived current; current-compensated voltageresponsive energizing-circuit means for energizing the restraint-circuit means, including an alternating-current source of a line-derived voltage, a serially connected resistance, and a serially connected inductance, a reversible and variableratio transformer-means associated with said resistance, a separate reversible and variable-ratio means associated with said inductance, and a variable alternating-current source of a line-tie rived current associated with said reversible and variable-ratio means for energizing both said resistance and said inductance; and means for varying the magnitude of the response of the operating force.

WILLIAM K. SONNEMANN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,380,164 Goldsborough July 10, 1945 2,393,983 Goldsborough Feb. 5, 1946

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