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Патент USA US2112058

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March 22, 1938.
y
i. D. APPLEGATE
2,112,058
SYSTEM OF COMPENSATION
‘
`Filed Jan. 16, 1956
WITNESSES:
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L
` aNvENToR
¿af? ÜÄ/Jp/eyaik‘e I
W
/â BY To-RNEY
Patented Mar. 22, 1938
2,112,053
UNITED STATES PATENT ÜFFICE
2,112,058
SYSTEM 0F COMPENSATION
Ivan D. Applegate, East McKeesport, Pa., assign
or to Westinghouse Electric & Manufacturing
Company, East Pittsburgh, Pa., a corporation
of Pennsylvania
Application January 16, 1936, Serial No. 59,403
l2 Claims. (Cl. .N1-_119)
My invention relates to compensating means
adapted for use with indicating devices and au
tomatic regulators and has particular relation to
line drop compensators associated with three
5 phase transmission and distribution circuits.
Automatic voltage regulators and indicating
devices are frequently located at some distance
from the point or" power distribution at which it
is desired that the voltage be maintained con
m stant, and for this reason it is necessary to pro
vide means for compensating their operation in
accordance With the voltage drop in the feeder
circuit. The total voltage drop varies with the
current flowing in the circuit and is the vector
15 sum of the resistance and reactance components
An additional object is to provide a system of
interconnection for the resistance and reactance
elements of compensators associated with but
two oi the three phases of the regulator circuit
which provides a three phase potential compen
sated for line drop in a symmetrical or balanced
ianner for changing conditions of circuit load 10
and power factor.
In practicing my invention, I connect in each
of two ol’ the three conductors which supply con
trol potential to the regulator a single phase conn
pensator assemblage including both resistance
and reactance elements.
To effect compensation, a device known as a
of these by a measure of the current in the con
line-drop compensator is employed in the con
trol circuit oi the regulator operating means.
Such a compensator duplicates the line drop
Voltage between the point in the power circuit to
which the voltage responsive element is con
nected `and the point in the circuit at which it is
desired the voltage responsive element should
respond, and introduces this voltage drop com
ponent into the voltmeter energizing circuit.
Through it a current is passed that is propor
ductor of the regulated circuit corresponding to
the phase with which the other compensator is
associated. By means of this cross-energizing
voltage drop across it that is proportional to the
voltage drop in the line.
In the application of polyphase~controlled
voltage regulators to three phase circuits, it is
further essential, especially when large compen~
sation is needed, that there be provided a com
C: CA
gie-phase compensator assemblages.
of voltage drop through the circuit impedance.
tional to the line current and which causes a
u
A more speciñc object is to achieve the abovea
stated results through the use of only two sin
pensated control potential which is representa
tive of the voltages acting in all three of the cir
cuit phases, otherwise for conditions ci circuit
unbalance, the regulator operation will not be
coincident with the actual circuit requirements.
,40
To obtain representative indications of the
type above discussed it has been necessary to
employ three single-phase compensator assem
blages, each of which involves a resistance ele
ment, a reactance element, an energizing current
transformer and other comparatively expensive
equipment. For some time attempts have been
made to obtain equivalent results by the use of
only two compensator equipments, however,
within my knowledge all of these have failed in
one or more important particulars.
Generally stated, the object of my invention
is to reduce the cost of the apparatus required
to accurately compensate the control oi regulators
for three-phase circuits under changing condi
tions of load, power factor, voltage and the like.
I then energize each
connection, and a reversal oi certain oi the eie- h
ment output connections, I am able to so modify
the voltages in two of the phases oi the control
supply circuit for the regulator that the result
ant potentials in all three phases of this circuit
accurately correspond at al1 times and under all
conditions to the requirements at the distant
point in the regulated circuit at which the regu
lator is intended to maintain constant Voltage.
My invention, together with additional objects
and advantages, will best he understood through 3 0
the following description of a speciñc embodi
ment when taken in conjunction with the ac
companying drawing, in which
Figure l is a diagrammatic View of apparatus
and circuits illustrating the simpliñed compen
sating System of my invention appli-ed to an auto
matic voltage regulator for a three-phase trans
mission circuit, and
Fig. 2 is a diagram of vectors illustrating the el()
mode of operation oi" my improved form oi com
pensator element connections.
Referring to the drawing, I have illustrated in
Fig. l the improved system of my invention as
being combined with the control supply circuits
of a voltage-adjusting equipment or regulator i6
associated with a three-phase transmission cir
cuit which comprises line conductors A, B and C
which terminate at a point distant from the reg
ulator. This equipment is controlled in conven- ,
tional manner by means of a Contact making
voltmeter or primary relay l2 which is responsive
to changes in the voltage of the regulated circuit.
The actuating winding I4 of this relay is sup
plied, through a connection which includes a 55
2
2,112,058
pair of potential transformers IS and a plurality
of rectifiers I8, with a measure of the voltage of
regulated circuit A-B-C.
Ul
ments of this compensator are reversed in order
In the operation of this regulating system,
that the compensating voltage components may
as long as the voltage of the regulated circuit
remains at the desired value, the representative
potential Ek impressed upon the primary relay
I2 maintains the movable contact member 20
thereof in the disengaged or mid-position illus
trated. Under this condition, no operation of
properly combine in the manner indicated in
Fig. 2.
the regulator I0 takes place. When, however,
the circuit Voltage drops, the resulting decrease
vectors E’ab, E'bc and E’ca. It will be noted that
this triangle is also symmetrical and in effect
consists of the basic or original triangle A--B-C
having its sides all similarly modified as to mag
nitude and rotated slightly about the point A.
It will thus be seen that for the 100% power
factor load conditions above assumed, a bal
anced line-drop compensation for the three
phase potentials has been effected in a manner
in relay potential Ei; causes contact member 20
to move upwardly and engage the “raise’y sta
tionary member to thereby correctively operate
the equipment I0 in the circuit voltage raising
direction.
In a similar manner a rise above the
desired value moves member 20 downwardly into
engagement with the “lower” stationary mem
20 ber which correctively operates the regulator I0
in the circuit Voltage lowering direction.
For the purpose of modifying the three phase
control potential impressed through the recti
fiers I8 upon the primary relay I2, I connect in
25 two of the conductors of the control supply
circuit single-phase compensator assemblages
generally indicated at 22 and 24. Each of these
assemblages comprises a reactance-compensating
element, in the form of a resistor 26 which may,
30 as shown, have an insulating transformer 28 con
nected thereacross, and a resistance-compensat
ing element in the form of an air-gap core type
of reactor 30. It will be noted that in the sys
tem of my invention the resistance and reactance
35 element structures are interchanged with respect
to those of the usual arrangement.
The compensator 22 which is connected in the
conductor 32 of the regulator supply circuit
(corresponding to the phase conductor B of the
40
leads by 90° the compensator energizing cur
rent Ibi. The output connections of both ele
regulated circuit) is energized through a cur
rent transformer 34 by a measure of the current
Ib flowing in the regulated circuit conductor C.
Similarly, the compensator 24 connected in con
ductor 36 of the regulator supply circuit (cor
responding to the phase conductor C of the reg
ulated circuit) is energized through a current
transformer 38 by a measure of the current Ib
acting in conductor B of the regulated circuit.
The effect of the illustrated connections is
shown by the vector diagram of Fig. 2 in which
the three voltages Ebb, Ebb and Em supplied
through transformers I6 and corresponding to
those acting in the regulated circuit at the point
of transformer connection, are shown as forming
the basic triangle A--B-C. At 100% power
factor, the currents flowing in the regulated cir
cuit conductors have the relative phase positions
indicated by vectors Ibi, Ibi and Ibi.
In energizing compensator 22, current Ici causes
the
reactor element 30 to introduce into the reg
60
ulator control supply circuit a voltage compo
nent RIci and the resistor element 2B to similarly
introduce a voltage component XIci. The re
actor 30 is so designed that the output voltage RIC
leads by 90° the energizing current Ic. The out
put connections from the resistor 26 of this com
pensator are reversed for a purpose later to be
explained.
Likewise, the energizing current Ibi flowing
70 from the secondary winding of the current trans
former 38 through the elements of compensator
24 causes the reactor 30 to introduce into the
regulator control supply circuit conductor 36, a
voltage component RIbi and the resistor 26 to
75 introduce a modifying component XIbi which
As a result of the introductions above named,
the potentials impressed upon the interconnected
rectifiers I 3 are modified to the extent repre
sented by the broken line triangle consisting of
entirely equivalent from a performance stand- i
point to that resulting from the use of three sin
gle phase compensator assemblages. The im
proved connection of my invention by requiring
only two of these assemblages thus reduces the
total cost to two-thirds.
The balanced operation is also preserved for
load currents of other power factors.
[c LA
For ex
ample, when the phase currents lag the cor
responding voltages of the regulated circuit by
90°, a condition representative of Zero percent ;
power factor, they occupy phase positions rep
resented in Fig. 2 by the vectors Ian, Ibb and Icb.
As a result of this shifting, the modifying poten
tials so combine as to produce resulting voltages
for impression upon the rectiiiers I8 which are
represented in Fig. 2 by the vectors E”bb, E"bb
and E”ba. It will be noted that the dotted tri
angle thus formed is also symmetrical, the change
in magnitude of all three of its sides being equal
and it being shifted in the opposite direction 40
around the point A.
If desired, a reactor 4U may be connected in
the manner shown in the remaining or third
conductor 42 of the regulator control supply cir
cuit for the purpose of securing a slightly more s
accurate balance in the output voltages thereof.
While in most cases this reactor 40 is not abso
lutely essential, in some instances it is useful to
compensate for the voltage drops through the
windings of the compensators 22 and 24 which ,
the current supplied to the regulator control de
vice by transformers Iû produces.
It will, therefore, be apparent that the system
of my invention functions at all times to provide
the desired balance in all three phases of its ¿1;
compensation. Because of the substantial sav
ings in equipment cost before pointed out, it
constitutes an exceedingly practical expedient.
It may furthermore be used in a wide variety of
regulator control and other comparable appli
cations of wiiic the system. represented in Fig. 1
is merely ilustrative. For example, equipment I0
il I)
may instead of being an induction or other type
of feeder circuit voltage regulator be in the form
of a generator voltage regulator of the rheostat
ie, vibratory, electronic-tube or any other equiv
alent type the supply circuit of which requires
that there be impressed t. ereon a three phase
control potential uniformly compensated for the
lin-e drop in all three of the phases of the regu- »l
lated circuit.
Application is thus not restricted
to situations in which a group of rectifiers (I8)
are interposed between the control element or
device (I2) and the source of control potential
supply.
75
2,112,058
3
Although I have shown and described a cer
of said elements by a measure of the power cur
tain specific embodiment of my invention, I am
fully aware that many modiñcations thereof are
rent in that phase of the circuit with which the
other of said compensators is associated.
6. A system oi balanced line-drop compensa
possible.
My invention, therefore, is not to be
restricted except insofar as is necessitated by
the prior art and by the scope of the appended
claims.
I claim as my invention:
1. In combination with a three-phase power
tion for a voltage responsive element connected
to be energized from a three-phase circuit com
prising, in combination with means for impress
ing upon said voltage responsive element meas
ures of the voltages acting in all three phases
circuit, means for adjusting the voltage of said
power circuit having a voltage responsive ele
thereof, a reactance-drop compensating element 10
ment, a control circuit for impressing a voltage
upon said voltage responsive element that is a
measure of the voltages acting in all three phases
of said circuit, a system of line-drop compensa
tion comprising a compensator connected in each
of two of the phases of said control circuit, and
means for circulating a current through each of
said compensators that is a measure of the power
current in that phase of the power circuit with
which the other of said compensators is associ
ated.
2. In combination with a three-phase power
circuit, means for adjusting the voltage of said
power circuit having a voltage responsive ele
ment, a control circuit for impressing a voltage
upon said voltage responsive element that is a
measure of the voltages acting in all three phases
of said circuit, a system for producing balanced
control-supply means and means for energizing
each of said elements by a measure of the pow
er current in that phase of the circuit with
30 line-drop compensation comprising resistance
and reactance compensator elements connected
in each of two of the phases of said control cir
cuit, and means for circulating a current through
each pair of compensator elements that is a
35 measure of the power current in that phase of the
circuit with which the other pair of said elements
is associated.
3. In combination with a three-phase power
circuit, means for adjusting the voltage of said
power circuit having a voltage responsive ele
ment, a control circuit for impressing a voltage
upon said voltage responsive element that is a
measure of the voltages acting in all three phases
of said circuit, a system of line-drop compensa
tion comprising a resistance and reactance com
pensator elements connected in each of two of
the phases of said control circuit, and means for
connected in each of two of the phases of said
which the other of said compensators is associ
ated.
7...A system of balanced line-drop compensa
tion i'or a voltage responsive element connected
to be energized from a three-phase circuit com
prising, in combination with means for impress
ing upon said voltage responsive element meas
ures of the voltages acting in all three phases
thereof, reactance and reactance drop compen
sating elements connected in each of two of the
phases of said control-supply means, and means
for energizing each oi said element pairs by a
measure of the power current in that phase o1'
the power current with which the other of said
element pairs is associated.
8. In combination, a main electrical circuit
having three phase conductors, a supply circuit
30
cordance with the summation of the voltages be 35
tween the several pairs of said phase conductors,
line drop compensating means connected in cír
cuit with each of two of said three supply con
ductors and each comprising means for intro
ducing voltage components into one of said sup 40
ply circuit conductors that is a measure of the
ohmic line drop and the reactive line drop, re
spectively, in the main circuit conductor corre
sponding to the other of said two supply con
ductors.
45
9. In compisation, a main electrical circuit
having three phase conductors, voltage respon
the other pair oí said compensators is associated,
said compensator connections being such that
balanced compensation results for varying condi
tween the several pairs of phase conductors of
said first named circuit, line drop compensating
thereof, a compensator connected in each or" two
of the phases of said control-supply means, and
means for circulating a current through each of
said compensators that is a measure of the pow
er current in that phase of the circuit with which
the other of said compensators is associated.
5. A system of balanced line-drop compensa
tion for a voltage responsive element connected
to be energized from a three-phase circuit com
prising, in combination with means for impress
ing upon said voltage responsive element meas
ures of the voltages acting in all three phases
thereof, a resistance-drop compensating element
connected in each of two of the phases of said con
75 trol-supply means and means for energizing each
25
sponsive means connected to be energized in ac
sive means, a three conductor supply circuit for
energizing said voltage responsive means in ac
cordance with the summation of the voltages be
60 ures of the voltages acting in all three phases
20
having three conductors corresponding to the
respective main circuit conductors, voltage re
circulating a current through each of said com
pensator elements that are a measure of the pow
er current in that phase of the circuit with which
tions of circuit load and power factor.
fi. A system of balanced line-drop compensa
tion for a voltage responsive element connected
to be energized from a three-phase circuit com
prising, in combination with means for impress
ing upon said Voltage responsive element meas
15
means connected in each of two of said three
supply conductors and comprising means for in
troducing a voltage component into each of said
supply conductors that is responsive to the ohmic
component oi line drop in the main phase con
ductor corresponding to the other of said supply
conductors, and means for introducing a voltage
component into each of said supply conductors 60
that is responsive to the reactive component of
line drop in the main phase conductor corre
sponding to the other of said supply conductors.
10. In combination, a three phase power cir
cuit, a voltage responsive device, a supply circuit 65
having three conductors corresponding to the
respective conductors of the three phase power
circuit for energizing said voltage responsive de
vice in accordance with the summation of the
voltages between the several pairs of phase con 70
ductors, line drop compensators connected in
each of two of sai-d supply circuit conductors
and each including a reactor element and a re
sistor element, and means for circulating a cur
rent through each of said compensators that is 75
4
2,112,058
a measure of the current in the power circuit
phase conductor with which the other compen
sator is associated.
11. In combination, a three phase power cir
cuit, a voltage responsive device, a supply cir
cuit having three conductors corresponding to
the respective conductors of the three phase
power circuit for energizing said voltage respon
sive device in accordance with the summation
of the voltages between the several pairs of
phase conductors, line drop compensators con
nected in each of two of said supply circuit con
ductors and each including a reactor element
and a resistor element, means for circulating
a current through each of said compensators
that is a measure of the current in the power
circuit phase conductor with which the other
compensator is associated, and a reactor in the
third supply circuit conductor.
12. In combination, a three phase power circuit,
a voltage responsive device, a supply circuit hav
ing three conductors corresponding to the re
spective conductors of the three phase power
circuit for energizing said voltage responsive de
vice in accordance with the summation of the
voltages between the several pairs of phase con
ductors, line drop compensators for introducing
compensating voltage components into each of
two of said supply circuit conductors and each in
cluding a reactor element having primary and
secondary windings coupled to effect a substan
tially 90° voltage phase shift, and a resistor ele
ment comprising an insulating transformer hav
10
ing primary and secondary windings and a re
sistor connected in shunt relation to said pri
mary winding, the secondary windings of the
compensator elements being connected in series 15
in their respective supply circuit conductors, and
means for circulating a current through the pri
mary windings of said compensator elements that
is a measure of the power current in that phase
of the power circuit corresponding to the other of 20
said two supply circuit conductors.
IVAN D. APPLEGATE.
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