close

Вход

Забыли?

вход по аккаунту

?

Патент USA US2406617

код для вставки
Aug. 27, 1946.
y H. w¿ -LENSNER
2,406,617
RELAY SYSTEM
’
Filed Sept. 14, 1944
my Ó:
Disïam‘ Carrier
External Fault
My @i
_WU-'Infernal Fa ult
7.
¿î k
/Dáase-ang/e beïween currents ai opp osiz‘e ends of [ine- sec?i or;
lNvENToR
ATTORNEY
Patented Aug. 27, '1946
2,406,617
UNITED STATES PATENT ’OFFICE
2,406,617
RELAY SYSTEM
Herbert W. Lensner, East 0range,'N. J., assigner
to Westinghouse Electric Corporation, East
Pittsburgh, Pa., a corporation of Pennsylvania
Application September 14, 1944, Serial No. 554,037
21 Claims.
1
(Cl. V75-294)
2
,
component, or other ground-fault detector
means, for increasing the effectiveness of the
single-phase voltage which is derived in response
to the positive-sequence component of the line
current. This provision makes it possible to ob
tain a ground-fault sensitivity of response, which
approximates that of a two- or three-phase fault,
notwithstanding the fact that the ground-fault
My present invention relates to a carrier-cur
rent or other pilot-channel phase-angle-detect
ing relaying system, adapted to protect a section
of a three-phase transmission-line against faults.
My present system is an improvement over the
system shown in an application of Mehring,
Goldsborough and myself, Serial No. 534,846, ñled
May 10, 1944.
The Mehring et al. system has a theoretically
may have a much smaller positive-sequence cur
possible defect, which might conceivably result in l0 rent-component.
an incorrect blocking-operation on an internal
This ground-fault-responsive sensitivity-in
B-C-to-ground fault, under system-conditions in
which substantially all of the positive-sequence
crease of a positive-sequence line-current re
sponse is of general application, not limited to
current comes from one end of the protected line
apparatus for comparing the current-directions
section, and substantially all of the zero-sequence
or relative phase-angles at the two ends or ter
minals of the protected line-section. It is also
particularly applicable to the control of a relay
current comes from the other end.
This comes
about by reason of the fact that the Mehring et al.
system utilizes a derived current-responsive
single-phase quantity, which is vectorially com
tube.
A more generally expressed object of my inven
tion is to provide a single relaying circuit which
pounded of the properly weighted positive- and
zero-sequence components of the line-current, to
alternately produce a succession of local operat
ing impulses during positive half-cycles of the
locally derived line-current quantity, and to
produces a uni-directional voltage of limited mag
nitude, in response to a detection of a predeter
mined ground-fault condition on the line, and
adds such a voltage in series with another voltage
component which is in some manner responsive to
transmit, to the other line-terminal, a succession
of restraining impulses during negative half
cycles of the locally derived line-current quantity.
An object of my present invention is to avoid
the possibility of such a diiiiculty by utilizing only
the positive-sequence component of the local line 30
current as the means for developing the alternat
ing successions of operating and restraining im
pulses, in combination with an overvoltage relay
the positive-sequence component of the line-cur
rent.
A still further object of my invention is to con
trol a relay-tube or other polarity-responsive de
vice, by causing it to be responsive to a pulsat
ing voltage having a phase which is responsive
substantially solely to the positive-sequence com
~ ponent of the line-current, and providing a uni
means which serves as a means for detecting the
directional voltage of substantially non-pulsatory
relative phase-angles between the two terminal C:
form, in the event of a predetermined ground
line-currents of the protected section, by respond
fault condition, for increasing the sensitivity of
ing to the operating impulses when they are not
response to the pulsating voltage. Such ground
4effectively opposed by restraining impulses re
fault response is preferably so arranged that it
ceived from a distant line-terminal.
will not by itself cause operation of the device.
As the positive-sequence line-current com 40
A still further object of my invention is to
ponent is not a reliable fault-detector, and as it
utilize a single-phase control-voltage to cause two
is sometimes desirable to avoid the transmission
tubes to be alternately conductive on positive and
of restraining impulses under normal fault-free
negative half-cycles, respectively, and to provide
line-operating conditions, a further object of my
a unidirectional voltage of substantially non
invention is to also provide a suitable multi 45 pulsatory form in a circuit of said tubes in a
responsive fault-detector means, capable of de
polarity facilitating the operative conductivity of
tecting the existence of any one of a plurality of
said tubes.
different kinds and phases of ground- and phase
With the foregoing and other objects in view,
faults, and to utilize said fault-detector means
my invention consists in the circuits, systems, ap
for supervising the operation of the phase-angle
paratus, combinations, parts, and methods, here
detecting relay-means, as by causing the positive
inafter described and claimed, and illustrated in
sequence means to be effective only when there is
the accompanying drawing, wherein:
a fault-indication by said fault-detector means.
Figure 1 is a diagrammatic view of circuits
A still further object of my present invention
and apparatus illustrating an embodiment of my
is to utilize a zero-sequence current- or voltage
55
invention, and
2,406,617
3
4
Figs. 2 to 13 are curve-diagrams which will be
referred to in the explanation of the invention.
In Fig. l, I show the terminal equipment for
only one terminal of a three-phase transmission
line I4, which is connected to a bus t5 through a
three-phase circuit-breaker I6. Only one termi
phase transmission-system. This fault-detector
nal equipment is illustrated, because the equip
tected line-section.
ments at the other line-terminal or terminals are,
FD is utilized to detect the presence of any one
of a number of different kinds of faults, prefer
ably all different kinds and phases of faults,
whether such faults occur within the confines of
the protected line-sectic-n, or outside of said pro
According lto my present invention, vthe posi
tive-sequence-responsive transformer T1 is uti
or may be, identical to the illustrated equipment.
The circuit-breaker i6 is illustrated as having a 10 lized to produce a succession of substantially flat
topped “operating” voltage-impulses of substan
trip-coil TC, and an auxiliary make-contact
breaker-switch lEa.
The three-phase line-current is derived by
tially constant magnitude during the positive
half-cycles of the positive-sequence line-current,
means of a bank of line-current transformers ll,
and to produce a succession of substantially nat
which respond to current-flow into the protected
line-section, at the terminal in question. This
three-phase line-current is fed into any suitable
phase-sequence network or filter EG, which is
topped “restraining” voltage-impulses of substan
provided with a zero-sequence or neutral-current
terminal Io, a pair of positive-sequence termi- <1
nals I1 in which a single~phase voltage is pro
duced, which is responsive substantially solely to
the positive-sequence component of the line-cur
rent7 and a pair of positive-plus-zero phase-se
quence terminals 110, in which a voltage is pro
duced in response to the vecto-rial sum of the
positive-sequence line-current, plus a constant
tially constant magnitude in response to the neg
ative half-cycles of the positive-sequence current
component. To this end, I p eferably utilize the
same means which is shown in +he aforesaid
Mehring et al. application, except that the means
is responsive to a single-phase voltage, the phase
of which is determined substantially solely by the
positive-sequence component of the local line
current, instead of using the positive-plus-zero
sequence-responsive network, as in said Mehring
et al. application.
As shown in Fig. l, l provide two gas «triodes
.assigned to the Westinghouse Electric & Manu
or other grid-controlled gas tubes GI and G2 of
a sustained-discharge type; that is, of a type in
which the grid ñres the tubes, or starts the dis
charge, but is unable to extinguish the tube or
facturing Company.
interrupt the discharge. The grids of these
times the` zero-sequence line-current, as in the
type HCB network which is shown in the Harder
patent 2,183,646, granted December i9, 1939, and
The zero-sequence network-terminal Io is uti
lized to energize a saturating zero-sequence-re
tubes GI and G2 are connected `to the respective
secondary terminals 23 and 24 of the tube-con
sponsive transformer To, the primary »winding
trolling transformer, in this case the positive
of which is connected in the neutral circuit of
the line-current transformers il. The pairs of
network-terminals I1 and Iio are respectively uti
sequence transformer T1. An intermediate Volt
age of the secondary transformer-circuit is de
rived from two serially connected resistors R2
lized to energize a saturating positive-sequence
and R3, which are connected across the second
transformer T1, and a saturating positive-plus to ary .terminals 23 and 24. 7l‘he connecting-point
zero sequence-responsive transformer T10.
25 between these resistors is connected to a nega
‘Usually and preferably, but not necessarily, in
tive battery-terminal or bus (-'-), through a C
accordance with my present invention, some, or
battery Ec, and the zero-sequence resistor RI,
preferably all, of the derived network-voltages
according to my invention. The C-battery Ec
are of limited magnitude, which may be accom
is so connected as to make the point 25 more
plished by making some or all of the transform
negative than the negative battery-terminal
ers T1, To and T10 saturating. The secondary ter
(_), or, in general, so as to make the point 25
minals of some or all_ of the transformers T1 To
have a potential too negative, by a predeter
and T10, particularly the positive-sequence trans
mined amount, to cause the tubes GI and G2 to
former T1, are also shunted by a voltage-limiting ,_
rire, under the impressed anode-cathode voltage
glow-tube I9, as described in the Harder patent.
The zero-sequence transformer To is utilized to
energize a load-resistor RI through a double
wave rectifier, such as the rectiñer-bridge 20, so
as to furnish a unidirectional current, having sub
conditions. The polarity of the zero-sequence
resisto-r Rl is in opposition to that of the C
battery Ec.
The cathode-circuits 2S and 21 of the gas tubes
Gl and G2 are connected to the negative bat
stantially no ripples, to said load-resistor RI.
The ripples may be still further removed by a
and R5, respectively. rI‘he anode-circuits 29 and
parallel-connected filter-capacitor FC l. The sat
tery-terminal (e) through cathode-resistors R4
3B of the respective gas tubes Gl and G2 are
urating nature oi' the zero-sequence transformer
respectively connected to plate-resistors R5 and
To results in producing a unidirectional current
R7, the other terminals of which are connected
of substantially limited magnitude, which is ap GU to a common conductor 3| which is connected,
plied to the resistor Rl, so as to produce a uni
through a make-contact 32 of the fault-detector
directional voltage-drop of a roughly constant
FD, to the positive battery-terminal (+L The
magnitude in the resistor Rl, whenever there is
two anode-circuits 29 and 30 of the gas tubes GI
a ground-fault on a transmission system. The
(55 and G2 are joined by an interconnecting circuit
negative terminal of the resistor Ri is indicated
containing a capacitor Cl.
Y
at 2 l, and the positive terminal at 22.
The two gas tubes Gl and G2 are thus con
The positive-plus-zero sequence-responsive
nected in a so-called “trigger” circuit, which op
transformer T10 is utilized to energize the oper
erates as follows: During positive-sequence line
ating coil of a fault-detector FD, which is in
current half-cycles of one polarity, which I shall
tended to be representative of any multi-respon
call the negative half-cycles, or more specifically
sive fault-detector means, or any equivalent com
- bination of fault-detector means, adapted to be
during the negative half-cycles of the derived
current-responsive voltage
of -.the positive
responsive to a plurality of different kinds and
sequence saturating Ytran'sformer T1, the second- i
phases of ground- and phase-faults on the three 75 ary transformer-terminal 23 -is positive. This
5
2,406,617
transformer-terminal 23 is also the grid-termi
nal of the gas tube GI.
At an early stage in
these negative half-cycles, the positive voltage of
the secondary terminal 23 with respect to the
intermediate secondary point 25, becomes more
positive than the blocking bias of the C-battery
Eo, or at least suiiiciently positive to cause the
first gas tube Gl to fire.
It will be understood
that the gas tubes have such characteristics that,
6
value close to the value which it had when the
tube Was firing, thus assisting in maintaining the
reversed tube-voltage for the instant necessary to
extinguish the tube.
As explained in the aforesaid Mehring et al.
application, the voltage-drops across th'e two
cathode-resistors R4 and R5 are utilized to pro
duce -two different efiects. The voltage-drop
across the cathode-resistor Ril of the ñrst gas
when they> are once fired, or when current is once 10 tube Gl is utilized to produce half-cycle impulses
started in their plate-cathode circuits, such
plate-cathode current will continue to ñow until
the voltage applied `across the plate and cathode
terminals of the tube is reduced to zero or re
versed, even for a moment.
VAt .the beginning of the next half-cycle of the
output-voltage of the positive-sequence trans
former T1, which I shall call a positive half
cycle, the other secondary terminal 24 becomes
positive with respect to the secondary intermedi
ate point 25, and íires the second gas tube G2.
Before the firing of the second tube G2, the
potential of its plate-circuit 30 was substantially
the potential of the. positive battery-terminal
(-{-), assuming that the fault-detector contact
32 is closed, while the potential of »the plate
circuit 29 of the ñrst tube Gl was at a somewhat
more negative value, due to the voltage-drop in
the plate-resistor RS of the first tube. When
the second tube G2 lires, however, its plate-cir- A
cuit 30 tends to drop -to the same potential as the
plate-circuit 29 of the ñrst tube, but the voltage
charge on the interconnecting capacitor C!
causes the potential of the anode-circuit 29 of
the ñrst tube GI to momentarily drop to a value
which is more negative than the potential of the
cathode circuit 25 of said first tube Gl, thus ex
tinguishing the ñrst tube Gl in the moment re
of square-topped positive voltages for supplying
a plate-voltage which is sufficient for initiating
and maintaining the operation of an oscillator
tube OSC of a carrier-current transmitter, by
connecting the plate-circuit 34 of the oscillator
tube OSC, through a radio-_frequency choke RFC,
to the cathode-circuit 2S of the lirst gas tube Gl, '
the cathode of the oscillator being connected, at
35, to the negative battery-terminal (_). The
voltage-drop across the cathode-resistor R5 of
the second gas tube G2 is utilized to apply an op
erating voltage-component from the cathode
circuit 2l of the second tube G2 to the grid-cir
cuit 36 of a relay-tube RT, which is shown near
the bottom oi Fig. l, and which will be subse
quently described. A voltage-drop resistor' R-l 5
is included in the connection between the cath
ode-circuit 2l of the second trigger-tube G2 and
the grid-circuit 36 of the relay-tube RT.
The transmitter-oscillator OSC has a grid-cir
cuit ¿3 which is connected to the cathode-circuit
35 of said oscillator through a grid-leak resistor
GL.
The anode-circuit 3d of the transmitter-oscil
lator OSC is coupled, by means of a blocking ca
pacitor BCE, to a conductor iig, which constitutes
one junction-point of a tuned circuit which in'
cludes the conductor G9, a capacitor C6, the
quired for the discharge of the interconnecting
capacitor Cl. In the next half-cycle, the iirst 4,0 cathode-terminal. 35, a capacitor Cl, the grid
terminal 43, and a variometer Vl, and thence
tube GI rires again, and in turn extinguishes .the
back
to the conducto-r ¿9. The conductor 49 and
second tube G2 by momentarily causing a nega
the grid-terminal ¿i3 are respectively connected
tive voltage to exist across its plate-cathode ter
to the grid-terminals M and ¿i5 of two ampliiier
minals.
tubes A! and A2 by means of blocking capacitors
The function of the interconnecting capacitor
BCS and B04, respectively.
CI, which shuts off the previously iiring gas tube
The ampliñer tubes Ai and A2 have a common
when the second tube begins to rire, is prefer
cathode-circuit 56, which is co-nnected to the
ably supplemented by two capacitors C4 and C5,
conductor 35, and h'ence the negative battery-ter
minal (_), through a cathode-resistor R8. The
tive cathode-resistors R4 and R5 of the two gas 50 grid-terminals ‘ifi and 45 of the amplifier-tubes
tubes GI and G2. The eiîect of thesershunting
Ai and A2 are respectively connected to the nega
capacitors C4 and C5 is to short-circuit the as
tive battery-terminal (_) through resistors
sociated cathode-resistor, R4 or R5, at the first
R-il and R-IZ. The amplifier-tubes Al and
instant of firing of the associated gas-tube, GI
A2 have plate-circuits 5l and 52, respectively,
or G2, as the case may be, thus momentarily
which are connecte-d to the primary-Winding ter
bringing the anode-potential of the newly iired 55 minals
of a coupling-transformer 53, The pri
tube to a value which is more negative than the
mary-Winding mid-point 5ft of this coupling
steady-state anode-potential of the tube which
transformer is connected to the positive battery
was previously firing.
terminal (-{-), and it is also connected, through
The interconnecting capacitor Cl, previous to
a blocking capacitor B05, to the cathode-termi
the firing of the newly ñred tube, was charged in 60 nal
50 of the amplifier-tubes.
such polarity as to momentarily tend to hold the
One
secondary-Winding terminal of the cou
anode-potential of the previously iiring tube
pling-transformer 53 is grounded, at 5i'. An
more negative than the anode-potential of the
other tap-point 53 thereof is connected to a vari
newly iìred tube.
65 ometer V2, and thence, through a coupling ca
The combined effect of the three capacitors Cl,
pacitor C_id, to one of the line-conductors of
C4 and C5 is to strongly depress the anode-po
the protected line-section, in a manner which is
tential of the tube which was ñring, at the lirst
Well-known and needs no further description.
instant of ñring of the second tube, making the
The secondary winding of the coupling-trans
anode-potential of the iirst tube momentarily
former 53 is also provided with another tap-point
more negative than its cathode-potential, thus 70 6U, which is connected to one terminal of th‘e pri
extinguishing the tube. At the same time, the
mary winding of a receiver-coupling transformer
shunting-capacitoi` C4 or C5, as Ithe case may
62, the other primary-winding terminal of which
be, of the tube that is being extinguished, mo
is connected, through a variable capacitor C_I l,
which are connected in shunt across the respec
mentarily holdsvup its cathode-potential to a .75 to the grounded point 5l'. The primary Winding
2,406,617
7
of the receiver-coupling transformer 62 is also
usually shunted by a voltage-limiting gas tube 64.
The receiver-coupling transformer 62 has, a
secondary winding, one terminal of which is
connected to the grid-circuit E6 of a detector
tube or receiver-tube REC, while th'e other sec
ondary-winding terminal is connected to the neg
ative battery-terminal (_). The secondariÍ
winding of the receiver-coupling transformer 62
is also shunted by a variable capacitor C_-l2, in l0
8
phase wave which has an approximately constant
limiting magnitude, for all except the smallest of
fault-currents, and which has a phase-angle
which is determined by the positive phase-se
quence component of the polyphase line-current
at the relaying station.
It is usually desirable to transmit carrier-cur
rent energy, for protective relaying purposes, only
during times of a fault somewhere on the trans
mission system, and hence it is desirable to uti
lize some sort of fault-detector. My previously
a manner which is usual in the art.
described fault-detector FD is intended to be rep
The receiver-tube REC is provided with a
resentative of a detector of this sort. When this
cathode-circuit 69 which is illustrated as being
fault-detector FD responds, it picks up its make
connected to a tap-point near the negative end
of a potentiometer ‘lil which is energized from the 1.5 contacts 32 and 88. The make-contact 32 ap
plies the direct-current battery-Voltage to the
positive and negative buses (-}-) and (_). This
plate-cathode circuits of the two gas triodes Gl
tube also has an anode-circuit "il, which is con
and G2, thus supervising the response to the posi
nected to the positive battery-terminal (-{-),
tive-sequence transformer T1. The make-con-through a radio-frequency choke RFC’.
tact 88 supervises the tripping circuit.
The plate or anode-circuit 1l of the receiver
At a very early stage in each positive half
tube REC is also coupled, by means of a capaci
cycle,
the positive-sequence-responsive filter-out
tor C_-|3, to a point 14 which is connected to the
put oi Fig. 2 overcomes the negative bias of the
cathode-circuit 21 of the second tube G2 through
C-battery EC, or at least it makes the grid-cir
a large, capacitor-charging resistor R-_I4. The
cuit 24 sufiiciently positive so that the gas triode
point 14 is also connected, through a capacitor
G2 fires, and produces a positive voltage-impulse,
C_M, to a conductor 15 which is connected to
which is obtained across the cathode-resistor R5,
the cathode-terminal 16 oi the lower diode of a
and comprises the voltage from the negative bat
double-wave rectiiier-valve RV. The plate-cir
tery-terminal (_) to the conductor 21 in Fig. 1,
cuit of this lower diode is connected to the grid
terminal 36 of the relay-tube RT and to the volt 30 as shown in Fig. 3. This is called the operating
voltage, because it is a voltage which tends to
age-drop or load-resistor R--l5. The other ter
make the grid-terminal 35 of the relay-tube R'I‘
minal of the load-resistor R-Itì is connected to
positive
with respect to the cathode-circuit 80 of
the cathode-circuit conductor 21 oi‘ the second
this tube, thus tending to cause current to flow
gas triode G2, as previously described. The up
in the plate-circuit 82 of the tube. Since the gas
per diode-circuit 11 of the double-wave rectifier
triode G2 is energized from battery-terminals
valve RV is connected, in the reverse polarity, be
(_) and (-l-) having a ñxed Voltage between
tween the circuits 21 and 15. The load-resistor
them, and since the plate-cathode circuits 30-_21
R-l5 is shunted by a radio-frequency by-pass
capacitor BPC.
of this triode are in series with fixed resistors
The relay-tube RT is provided with a cathode
circuit 8D which is connected to an intermediate
R1 and R5, the positive voltage-impulses which
make up the operating voltage are square-topped,
point of a potentiometer 6| which is energized
across the battery-terminals (_) and (-1-). The
relay-tube RT is also provided with a plate-cir
cuit 82, which is connected to the positive bat
of the positive-sequence-responsive älter-out
and of a substantially constant magnitude, quite
irrespective oi >the magnitude or the wave-form
put I1.
,
A disadvantage which has heretofore lstood in
the way of utilizing a positive-sequence current
tery-terminal (-\-), through the primary wind
ing of a relay-coupling transformer 84, the sec
ondary of which is connected, through a recti
fier-bridge Bâ, to the operating coil R of a trip
ping-relay R. The relay R is provided with a ,
make-contact B1, which is shown near the top
of Fig. 1, in series with the trip-coil TC of the
response in the protection against line-faults has
been the very extreme variations which are ob
tained in the magnitude of the positive-sequence
current-component under diiîerent fault-condi
tions, ranging from a very large positive-sequence
current, in case of a three-phase fault, to a posi
tive-sequence current which may be many times
circuit-breaker I6. The output of the rectiñer
bridge 86 may be smoothed, if desired, by means
, lower than the maximum power-load current in
of a filter-capacitor FCZ.
the case of a single line-to-ground iauit of high
The fault-detector FD is provided with a lmalie
impedance. This condition is aggravated at a
contact 88, which is connected in the tripping cir
line-terminal which has no source of positive
cuit of the circuit-breaker I6, said tripping cir
sequence energy, so that only positive-sequence
cuit being traceable from the negative battery
terminal (_), through the fault-detector make 60 component ci' the fault-current is that which is
contributed by the rotating electric machines
contact 8&1, and the tripping-relay make-contact
which are connected to that terminal of the line.
R, to the trip-coil TC, and thence through the
It is for this reason that I prefer to provide the
breaker-switch iöa to the positive battery termi
previously described zero-sequence resistor RI,
nal (-l-).
o-r some equivalent means for in any manner in
The operation of the apparatus shown in Fig. 1
creasing the sensitivity of the response of the gas
may best be explained with reference to the
triodes Gl and G2 to the positive-sequence line
curve-diagrams oi Figs. 2 to 13. The positive-se
current component. In its generic aspects, my
quence output-terminals I1 of the filter I8 in Fig.
invention relates to any means for accomplish
1, with their associated saturating transformer
ing this sensitivity-increasing purpose in the
T1 and voltage-limiting gas tube I9, produce a
event of a ground-fault. A preferred form of
single-phase, positive-sequence-responsive out
embodiment of such a means is shown in Fig. 1,
which is to be taken as illustrative, also, cf the
put-voltage, one part of which appears across the
conductors 24 and 25. This positive-sequence
responsive output-voltage is preferably, as indi
cated in Fig. 2, a substantially sinusoidal single
75
generic idea.
In the illustrated form of my invention, as
2,406,617
10
shown in Fig. 1, the zero-sequence resistor RI
is connected in series with the C-battery Eo, in
a polarity opposite to that of the C-battery. The
negative bias or voltage of the C-battery Eo is
preferably made abnormally large, or larger than
is just barely necessary to prevent excitation of
of the filter-output of Fig. 2, as shown diagram
matically in Fig. 4.
In Fig. 4, the frequency of the carrier-current
waves cannot be shown to scale, because the car
rier-current frequency is actually so high that it
would not begin to be shown in the space which
the gas tubes GI and G2 when no single-phase
we have allotted to Fig. 4.
control-voltage is applied across the transformer
After the ñrst impulse of carrier-current trans
terminals 23 and 2d, which also constitute the
grid-terminals of the respective gas tubes GI and lO mission, during the ñrst negative half-cycle of
the positive-sequence älter-output after the re
G2. In the event of a phase-fault, involving two
sponse
of the fault-detector FD, the iirst-men
or more of the line-conductors E4, the positive
tioned gas triode G2 again becomes conducting,
sequence current-component will be large enough
extinguishing the triode GI, and thus interrupt
to saturate the positive-sequence transformer T1,
ing the carrier-current transmission for a half
and large enough to exceed the setting of the volt
cycle period, corresponding to the next positive
half-cycle of the positive-sequence filter-output.
age-limiting gas tube i9, so as to produce a iixed
constant magnitude of single-phase voltage which
It will be noted that the action just described
occurs at both terminals of the protected line-sec
tion i d, or at all of the terminals, in case the Dro
tected line-section has more than two terminals.
It will be noted that the equipment at each termi
is sufficient to cause the respective gas triodes Gl
and G2 to become conducting at an early part
of alternate half-cycles of the Voltage-supply, as
previously explained.
In the event, however, of a single line-to
ground fault through a very high impedance,
nal responds to the positive-sequence component
of the line-current input into the protected line
section at its own terminal, that is, from the bus
such as would be obtained by a broken line-con
ductor lying upo-n dry or frozen ground, the posi
i ‘5 at that terminal. In the event of an internal
fault, that is, a fault within the confines of the
tive-sequence Voltage component or output of the
transformer T1 might not be large enough to sat
isfactorily control the gas triodes Gl and G2. In
protected line-section, the positive-sequence com
such a case, however, a Zero-sequence current
component will be present, which energizes the
zero-sequence transformer To to saturation, and
the output of this transformer is rectified and ap
plied to the load-resistor Rl in such polarity as
s.
of)
with each other, because the positive-sequence
terminal-voltages of the line are not greatly out
of phase with each other, while the line-imped
ance which limits the fault-current from each
terminal to the fault-location has approximately
to produce a voltage-drop or potential opposite
to the potential of the grid-biasing battery Eo,
but preferably having a limited magnitude such
that the zero-sequence-responsive unidirectional
the same impedance-angle in each case. For an
internal fault, therefore, it may be assumed, as a
voltage will not of itself suffice to cause the gas
first approximation, that the positive-sequence
triodes Gl and G2 to begin to transmit plate
cathode current in the absence of any positive
sequence-responsive single-phase control-voltage
across the terminals 23 and 24.
The zero-sequence resistor RI nevertheless neu
tralizes some or all of the C-battery voltage Ec,
as indicated at 22 in Fig. 1. Thus it predisposes i
the grids of both of the gas triodes GI and G2
to be ready to make the tubes conductive when
their respective grids are made just a little bit
more positive with respect to their tube-cathodes,
as by the application of a relatively small alter
nating voltage, applied across the grid-terminals
23 and 24, from the positive-sequence transform
er T1.
At a very early period in each negative half
cycle of the filter-output which is shown in Fig.
2, the other gas triode Gl of Fig. 1 ñres, immedi
ately extinguishing the previously ñring triode
G2, in a manner which has previously been de
scribed. The operation of this other gas triode
impulses which alternate with the positive im
pulses which constitute the operating voltage of
Fig. 3. The positive voltage-impulses of this other
terminal other than the illustrated line-terminal,
is transmitted at the same time as the local car
rier which is shown in Fig. 4, for an internal fault,
that is, out of phase with the operating impulses
of Fig. 3.
.
In the event or” an external fault, however, posi
tive-sequence current will be flowing out of the
line-terminal which is closest to the external
fault, and it will be Flowing into the protected
line-section at at least one other terminal. Since
each terminal equipment responds to a positive
sequence current-direction looking into the pro
tected line-section at that terminal, the line-cur
rent at the terminal closest to the external fault
Will be reversed, approximately 180° in the ideal
terminal. Hence, at each terminal, local carrier
will be transmitted at certain half-cycles of the
line-frequency, as shown in Fig. 4, and distant
carrier will be transmitted at some distant termi
nal during line-frequency half-cycles which are
displaced approximately 180° (inthe ideal case)
with respect to the line-frequency half-cycles of
the local carrier. Fig. 6 depicts the distant car
rier-current transmission for an external fault.
In the operation of the particular system shown
triode Gl are obtained across the cathode-re
sistor R4, in the form of a positive voltage which
appears between the negative battery-terminal
(~-) and the conductor 2t, which is connected to
lthe plate-circuit S4 of the transmitter-oscillator
OSC, through the radio-frequency choke RFC of
in Fig. it will be noted that carrier-current en
ergy, from both the local and distant transmit
ters. is received by the receiver-tube REC, so as
to produce a plate-cathode current through this
tube during periods when the carrier-current en
Fig. l. This causes the oscillator OSC to immedi
ately begin oscillating, thus initiating the trans
The transmission of carrier
continues, at approximately its full, constant
strength, as long as the gas triode Gi is ñring,
which is to say, during the negative haii-cycles
fault-current components are in phase with each
other at both or each of the line-terminals, This
is depicted in Fig. 5, which shows that the distant
carrier, which is transmitted at another line
case, with respect to the current in some other
Gl produces a succession of positive voltage- ~
mission cf carrier.
ponent of the fault-current will be ñowing into
the line-section at each terminal thereof, and
these fault-currents will be more or less in phase
ergy is being received.
.
K
When no carrier-current energy is being re
2,406,617
11
positive battery-terminal. (-1-) , and hence the ca
pacitor C-l3 is charged in accordance with the
The receiver-tube REC preferably has a con
stant-current characteristic, so that whenever its
potential-diiîerence between said anode-termi
nal ll of the receiver and the cathode-terminal
conduct-or 21 of the second gas triode G2, the
grid permits plate-current to flow, the plate-cur
rent will have an approximately constant value.
Thus, as shown in Fig. 8, the half-cycles of re
receiver-connected terminal 0f the Capacitor
C-l3 being positive. The conductor 2l has a po
tential such as is depicted in Fig. 3, varying be
tween Zero, which is taken as the potential or the
negative battery-terminal (_), and a fraction of
the total battery-voltage, which is utilized as the
ceiver plate-current, during which carrier-current
energy is being received by the receiver-tube REC
Afrom the distant carrier, transmitted from some
other line-terminal, are of
approximately
ñxed magnitude, regardless of carrier-current
attenuation. Hence the restraining voltage-iin
operating-voltage for the grid-circuit 3S of the
relay-tube RT, this operating-voltage being the
voltage-drop or the cathode-resistor R5 of the
pulses in the resistor R--Eä are oi"
mately ñxed magnitude.
second gas triode G2, whenever the latter is firing.
When the carrier-current energy is received,
the receiver-tube REC becomes conducting, pull
ing down the potential of its anode-terminal 'Il
current impulses which are received from the dis
nitude as the half-cycle impulses or plate-current
which are produced when carrier-current energy
is being received from the local transmitter, even
though the local signals may he the stronger.
It is preferable, also, that the relay-tube RT
C--|3, and causing it to discharge, drawing cur
rent through the load-resistor R--lli and the ~»
lower diode of the rectifier-valve RV, said diode
being connected in such polarity as to permit cur
rent-now in the direction from the conductor 2l
to the conductor 35, and thence through the lower
diode to the conductor 16 and the capacitors
At the same time, a much
capacitor-charging resistance R--i4, which is
utilized to charge the capacitor C-I 3.
During the periods when no carrier-current
energy is being received, in the illustrated form
of embodiment of my invention, the receiver
plate-circuit 'Il again becomes quite positive, so
that the upper diode-circuit 'H of the rectifier
valve RV becomes conducting and charges the d@
capacitor C--l4, making the terminal 74 positive
and the terminal 'l5 negative, thus causing the
capacitor C-M to act as a voltage-doubler for
doubling the effective voltage of the capacitor
C-l3.
When, therefore, carrier-current energy is
again received, on the next half-cycle of the line
frequency current, the two capacitors C--M and
C-I3 discharge through the load-resistor R-I5,
producing
a
negative
or
restraining
duced by the current-flow in the cathode-resistor
R5 or the second gas tube G2.
The radio-frequency or carrier frequency coin
ponent of the plate-voltage of the receiver-tube
REC is by-passed from the load-resistor R-EB
by the by-passing capacitor BPC.
that its plate-current will be constant, as shown
in Fig. l1, without sensitive dependence upon the
exact amount of the restraining voltage, pro
duced by the receipt of carrier-current energy, as
shown in Fig. 8, is not important, so long as said
restraining voltage is greater than the operating
voltage of Fig. 3, or the voltage-drop in the re
sistor R5, by a safe margin.
It is further to be noted that the only carrier
current response of any moment is the response
to the distant carrier, that is, the carrier-cur
rent impulses which are transmitted from some
other line-terminal or terminals. The carrier
current energy received from the local carrier
current transmitter is immaterial, because, by the
very nature of the control, it is always trans
mitted (and received) during the half-cycles al
ternating between the half-cycles when the oper
ating impulses of Fig. 3 are present.
The grid-voltage of the relay-tube RT is thus
made up of three components: First, there is a
negative grid-bias consisting of the voltage be
.
voltage-drop in said load resistor lic-E5, malr
ing the conductor 35i, and hence the grid of
the relay tube RT, negative with respect to
the potential of the cathode-circuit conductor 21
of the second tube G2. The reception of carrier- I
current thus causes the capacitors C-lli and
C-l3 to discharge, producing a voltage-drop in
the load-resistor R--l5, making the grid of the
relay-tube RT more negative, and thus effec
tually preventing this tube from operating in re (50
sponse to the operating-voltage which is pro
shall have a constant-current characteristic, so
precise magnitude of its grid-voltage. Thus, the
smaller current ñows through the inucn larger
thus
approxi
The receiver plate
tant carrier are of approximately the same mag
to a point which is more or less close to the po
tential of the negative battery-terminal (-) ,
thus more or less short-circuiting the capacitor
C-l4 and C--l3.
12
terminal is exactly 180° out of phase with the
inwardly flowing positive-sequence current or
currents at the other terminal or terminals of the
protected line section.
ceived, the anode-terminal 'H of the receiver
tube REC is practically at the potential of the
tween the potentiometer-tap 8B and the nega
tive battery-terminal, which is sufficient to bias
the grid of the relay-tube RT so that no plate
current flows in said tube when there is no re
straining or operating voltage present.
A sec
ond component of the grid-voltage of the relay
tube RT is the operating voltage, in the form of
positive voltage-impulses produced whenever the
cathode-circuit current of the second gas tube
G2 flows through the cathode-resistor R5, as
shown in Fig. 3. The third grid-voltage com
ponent of the relay-tube RT is the restraining
voltage, in the form 0f negative voltage-impulses
as shown in Figs. '7 and 8, for an internal fault
and an external fault, respectively. This re
straining voltage is produced by the discharge
of the capacitors C-lê and C-l3 through the
resistor R-l5 whenever carrier-current energy
is being received, although the restraining im
Fig. 7 shows the negative or restraining volt
age, across the resistor R-Iâu for an internal
pulses which are received from a distant line
terminal are the only ones of importance. The
of the fault-currents are in phase with each
other at both or all of the line-terminals, while
shown in Figs. 9 and 10, for an internal fault and
an external fault, respectively.
Since the relay-tube RT will be operated, or
carry a plate-current, only when its grid is suf
fault in which the positive-sequence components TO resultant grid-voltage of the relay-tube RT is
Fig. 8 shows the corresponding restraining volt
age for an external fault in which the outwardly
ñowing positive-sequence current at one line
ñciently positive with respect to its cathode, a
2,406,617
plate-current will ñow in the relay-tube RT only
during the positive-half-cycles of the grid-volt
ages shown in Figs. 9 and l0, that is, only when
the local operating impulses of the second-valve
cathode-circuit conductor 21 and its cathode-re
sistor R5 are not opposed by the restraining im
pulses received from a distant line-terminal.
When there is an internal fault, accompanied
14
only upon the relative lengths of the time-periods
during which the plate-current is iiowing, as
shown in Fig. 13.
Since the relay-current is measured in milliam
peres, it is usually more convenient to utilize a
sensitive polarized relay R, or other sensitive
direct-current relay R, to respond to this plate
current, rather than utilizing an alternating-cur
by fault-currents which are in phase with each
rent relay for this purpose. For this reason, I
other at the several line-terminals, the plate 10 have provided the plate-circuit transformer 84,
current of the relay-tube RT takes the form of
and the rectiiier-bridge 86, so that I may utilize
a succession of square-topped half-cycles corre~
sponding in timing to the line-frequency half
cycles when the second gas tube G2 is ñring, as
depicted in Fig. 11, thus energizing the local trip
ping-relay R and causing a local tripping-opera
tion. In the case of an external fault, with line
a sensitive direct-current milliampere-relay R, as
shown in Fig. l.
The relay R, as previously described, has a
make-contact 8l in the tripping-circuit of the
breaker lâ, so that, whenever the relay R picks
up, the circuit~breaker l5 is tripped. Because of
the sensitive nature of the relay R, and the possi
currents exactly 180° out of phase with each other,
the grid-biasing voltage of the relay-tube RT is
of shock-excitation of the carrier-current
entirely negative, as shown in Fig. 10, and the 20 bility
receiver-circuits due to static conditions, or the
plate-current of the relay-tube RT is zero, as
like, it is usually desirable to safeguard the trip
shown in Fig. 12, meaning no response of the re
ping-circuit by providing some additional fault
lay R, and hence no tripping-operation.
responsive contact, in addition to the contact 8l
While I have discussed the ideal cases of an
of the relay R, and I have provided for this, in
internal fault in which there is a 0° phase-angle
Fig. 1, by means of the contact 88 of the fault
between the terminal positive-sequence line
detector FD, which is intended to be representa
current components, and an external fault in
tive of any fault-detector contact which is con
which there is a 189° phase-displacement, count
trolled independently of the carrier~current
ing inwardly ñowing currents as positive, or in
channel, and which is intended merely to make
phase With each other, at each terminal, it is
sure that there is a fault somewhere on the trans
to be noted that, in actual cases, the terminal
mission system, before a tripping operation is
positive-sequence line-current components for
internal faults will not, in general, be exactly in
phase with each other, but will vary in phase,
by a certain amount, so that the impulses of the
plate-current of the relay-tube will be shorter
than the half-cycle impulses shown in Fig. l1,
depending upon the phase-angle, because the op
erating impulses of Fig. 3 will be partially over
lapped or blocked by received impulses from the
distant transmitter, according to the phase-angle
between the positive-sequence fault-current com
ponents at the different stations.
Fig. 13 shows a plot of the integrated, or root
means«square, or averaged, current in the relay
coil R, in milliamperes, plotted against the phase
angle of the terminal line-currents. It shows
that, as the phase-angle departs from zero, in
either the leading direction or the lagging direc
tion, the relay-current falls off, or becomes small
er and smaller, until the phase-angle becomes
180°. The tripping-relay R is really an overcur
rent relay, and it is adjusted to have a pick-up
value 9S (Fig. 13) which permits the internal
fault currents at the several terminals to be out
of phase with each other as much as 120°, While
permitted in response to the receiver-relay con
tact R.
Since my illustrated system utilizes only one
fault-detector, which is shown at FD, it is neces
sary to guard against erroneous relay-operation
in the event of a distant fault which might cause
a picking up of the fault-detector at only one end
or" the protected line-section. ’I‘o eliminate the
possibility of incorrect relaying under these con
ditions, I prefer to arrange the circuit~constants
so that the gas triode Gl, which controls carrier,
ñres at a lower voltage of the ñlter output-circuit
23, 24 than the gas triode G2 which provides
operating voltage to the grid-circuit 3B of the
relay-tube RT.
'
The gas triode Gi which controls carrier ñres
preferably immediately upon the closure of the
contact 32 of the detector FD. The second gas
triode G2 fires at a grid-voltage which is suffi
ciently above the pick-up voltage of the detector
FD to insure that the fault«detectors FD at both
ends of the line-section will pick up before the
second gas triode G2 applies an operating voltage
to the relay~tube RT at either end of the line.
Consequently, if only one fault-detector picks up,
still permitting the fault-responsive tripping-re
at only one end of the line, there will not be
lay ER to pick
This leaves the phase-angles
enough control~voltage across 23 and 24 to cause
between 120° and 180° to represent external-fault
the diode GZ to nre at either end of the line, and
conditions, during which the relay R does not 60 hence the relayf~tube RT cannot carry current to
pick up. It will be understood, of course, that
operate the tripping-relay R at either end of the
the pick~up value of the relay-current can be
line.
set for any desired magnitude, correspondingr to
In Fig. l, the resistor R2 is illustrated as being
any desired phase-angle between the terminal
larger than R3, so that, with identical tubes GI
line-currents, in accordance with the necessities
and G2, the tube Gl will receive the larger por
of special conditions existing on any particular
tion or" the voltage across
and 243. The tube
line.
G2 may nre at a voltage which is 20% to 50%
The relay-tube RT preferably has a. constant
above the control-voltage (across 23 and ‘24)
current characteristic, so that whenever its grid
which results in the ñring'oi the tube Gi.
permits plate-current to flow, the plate-current '
It will be observed that I obtain phase-angle
will have an approximately constant value, as
comparison of the line-currents at different ter~
shown in Fig. l1, without sensitive dependence
minals of a protected lineeseetion by utilizing the
upon the precise magnitude of the grid-voltage.
positive-sequence components oi the line~curHence, the integrated, or root-mean-square, or
rents at the respective llne~terminals as phase
average, value of the plate-current will depend ~1 Ul angle control-means, for providing, at each ter
2,406,617
15
minal, a succession of flat-topped constant-mag
nitude positive operating-impulses which are
effective locally, and, alternating therewith, a
succession of flat-topped constant-magnitude
negative restraining-impulses which are received
from the other line-terminal or terminals. I also
supervise this positive-sequence response with a
multi-responsive fault-detector means, prefer
ably in the form of a single voltage E10 Which is
a composite ci various phase-sequence compo
nents or phases of the line-current. I further
increase the sensitivity of my response to the pos
itive-sequence components oi ground-fault cur
rents, by means of a ground-fault detector, pref
erably a ground-fault detector which responds
to ground faults by producing a constant-magni
tude unidirectional voltage of substantially non
16
of a plurality of diiiei‘ent kinds and phases of
ground- and phase-»faults with uncertainty as to
whether the fault is inside of or outside of the
protected line-section, and means for causing
said local control-means and said pilot-channel
means to be eiîectively operative only when there
is a fault-indication by said fault-detector means.
e. The invention as defined in claim 1, in com
bination with ground-fault detector-means, re
sponsive to line-»conditions at said terminal, for
increasing the effectiveness of said single-phase
voltage in the event of a predetermined ground
fault condition.
d. Multi-responsive
fault-detector
me ans ,
adapted to be responsive to a plurality of differ
ent kinds and phases oi ground- and phase-faults
on a three-phase line, comprising positive-se
quence means operative to develop a voltage
which is substantially solely responsive to the
I have also provided a novel control-circuit in
which a constant-magnitude unidirectional volt 20 positive-sequence component of the line-current,
means responsive to said. voltage, and ground
age is added to a single-phase positive-sequence
fault detector-means, responsive to line-condi
responsive voltage Whenever there is a ground
tions, ior increasing the effectiveness of said
fault on the system. I have also made use of
voltage in the event of a predetermined ground
such a combination of a direct-current voltage
fault condition.
added to an alternating-current voltage, in a gas
5. Multi-responsive fault-detector m e an s ,
tube GI or G2, each oi which is representative of
adapted to be responsive to a plurality of different
any polarity-responsive device which is respon.
kinds and phases of ground- and phase-faults
sive to the voltage half-Waves ci only one polarity.
on a three-phase line, comprising positive-se
While I have illustrated my invention in but
quence means operative to develop a voltage
a single form of embodiment, which I at present
which is substantially solely responsive to the
prefer, I desire it to be understood that such il
positive-sequence component of the line-current,
lustration is only illustrative, and that various
a tube, means for causing said tube to operate
changes of omission and addition and substi
response to said voltage, and means for in
tution may be made without departing from
creasing t e sensitivity of tube-response to said
many of the esesntial features of my invention,
voltage in response to a predetermined ground
as will be well understood by those skilled in the
art. I desire, therefore, that the appended
fault condition on the line.
'7. lvIulti-responsive fault-detector m e ans ,
claims shall be accorded the broadest construc
adapted to be responsive to a plurality of differ
tion consistent with their language.
pulsatory form.
I claim as my invention:
l. Terminal equipuent ior one terminal cfa
to ent kinds and phases of ground- and phase-faults
on a three-phase line, comprising means oper
pilot~~channel phase-angle-detecting relaying
ative to develop a pulsating voltage having a
system adapted to protect a section of a three
phase which is responsive substantially solely to
the positive-sequence compbnent of the line
current, ground-fault detector-means operative
to develop a ground-fault-responsive voltage
phase transmission-line against faults, compris
ing means operative to develop a single-phase
voltage having a phase which is responsive sub
stantially solely to the positive-sequence compo
nent of the line-current at said terminal, local
control-means operative to develop a succession
of operating impulses in response to positive half
cycles oi
voltage, pilot-channel means oper
ative to transmit a succession of restraining
impulses and to make them effective at another
line-terminal or terminals in response to nega
tive half-cycles of said voltage, and phase-angle
detecting relay-means operative to respond to
said operating impulses when they are not effec
tively opposed by restraining impulses received
from a distant line-terminal.
2. The invention as defined in claim l, in com
bination with multi-responsive fault-detector
responsive to line-conditions at said ter
minal, for detecting the existence of any one of
a plurality of different kinds and phases of
ground- and phase-faults with uncertainty as to
whether the fault is inside oi or outside of the
protected line-section, and means for supervis
ing the operation oi said phase-angle-detecting
relay-means in response to a fault-indication by
said. fault-detector means.
3. The invention as defined in claim 1, in com
component of a limited magnitude and a uni
directional form in the event of a predetermined
ground-fault condition on the line, and circuit
means for combining said voltage-components in
series.
8. Multi-responsive
fault-detector
me ans ,
adapted to be responsive to a plurality of differ
ent kinds and phases of ground- and phase-faults
on a three-phase line, comprising means oper
ative to develop a pulsating voltage having a
phase which is responsive substantially solely to
the positive-sequence component of the line-cur
rent, ground-fault detector-means, responsive to
GO line-conditions, for developing a uni-directional
voltage of substantially non-pulsatory form in
the event of a predetermined ground-fault con
dition, a polarity-responsive device, means for
causing said device to be operatively conducting
on alternate half-cycles of the line-current fre
quency in response to said pulsating voltage, and
means, responsive to said substantially non-pul
satory voltage, for increasing the sensitivity of
the aforesaid response to the pulsating voltage.
9. Multi-responsive
fault-detector
means,
adapted to be responsive to a plurality of dif
ferent kinds and phases of ground- and phase
bination with multi-responsive fault-detector
faults on a three-phase line, comprising a tube,
means, responsive to line-conditions at said ter
means for normally providing a tube-circuit volt
minal, for detecting the existence of any one 75 age which prevents the tube from becoming ef
2,406,617
17
fectively
conductive,
ground-fault
18
detector
means, responsive to line-conditions, for at times
providing a unidirectional voltage of substantial
ly non-pulsatory form in a circuit, of said tube
and in the polarity tending to make the tube
become effectively conductive, means operative
to develop a pulsating voltage having a phase
which is responsive substantially solely to the
positive-sequence'component of the line-current,
and means for making said pulsating voltage ef 10
fective in a circuit of said tube in such manner
as to tend to cause the tube to be operatively con
ductive on alternate half-cycles of the line-cur
rent frequency in response to the pulsations of
effective at another line-terminal or terminals in
response to negative half-cycles of said pulsating
voltage, and phase-angle-detecting relay-means
operative to respond to said operating impulses
When they are not effectively opposed by restrain
ing impulses received from a distant line-termi
nal.
l5. Multi-responsive
fault - detector
means,
adapted to be responsive to a plurality of different
kinds and phases of ground- and phase-faults on
a three-phase line, comprising current-respon
10. The invention as deiined in claim 9, char
sive voltage-developing means operative to de
velop a voltage-component which is responsive
to a function of the three-phase line-current,
ground-fault detector-means for selectively re
sponding to ground-fault line-conditions more
acterized by said non-pulsatory voltage having a
sensitively than said current-responsive voltage
said pulsating voltage.
limited magnitude which is insuiîicient to cause
developing means, said ground-fault-detector
any material operative conduction of the tube in
means being operative to develop a ground-fault
the absence of a positive-sequence-responsive pul 20 responsive voltage-component of a limited mag
sating voltage.
nitude and a unidirectional form, circuit-means
11. Multi-responsive fault-detector means,
for combining said voltage-components in series,
adapted to be responsive to a plurality of dif
and means responsive to said combined voltage
components.
ferent kinds and phases of ground- and phase
faults on a three-phase line, comprising a tube
16. Multi-responsive fault-detector means,
having control-circuit means, a direct-current
adapted to be responsive to a plurality of diñerent
plate-voltage supply-circuit for said tube, means
kinds and phases of ground- and phase-faults on
for normally providing a control-circuit voltage
a three-phase line, comprising current-responsive
which prevents the tube from becoming eiîec
tively conductive, ground-fault detector-means,
Voltage-developing,means operative to develop a
pulsating voltage-component having a phase
responsive to line-conditions, for at times pro
viding a unidirectional voltage of substantially
phase line-current, ground-fault detector-means
which is responsive to a function of the three
for selectively responding to ground-fault line
of _said tube and in the polarity tending to make
conditions more sensitively than said current-re
the tube become effectively conducting, means 35 sponsive voltage-developing means, said ground
operative to develop a pulsating voltage having a
fault detector-means being operative to develop
non-pulsatory form in a control-circuit means
phase which is responsive substantially solely to
a unidirectional voltage of substantially non
the positive-sequence component of the line-cur
pulsatory form, a polarity-responsive device,
rent, and means for making said pulsating volt
means for causing said device to be operatively
age effective in aicontrol-circuit means of said 40 conducting on alternate half-cycles of the line
current frequency in response to said pulsating
tube in such manner as to tend to cause the tube _
to be operatively conductive on alternate half
voltage, and means, responsive to said substan
cycles of the line-current frequency in response
tially non-pulsatory voltage, for increasing the
to the pulsations of said pulsating voltage.
sensitivity of the aforesaid response to the pul
sating voltage.
12. The invention as denned in claim 11, char
acterized by said non-pulsatory voltage having a
17. Terminal equipment for one terminal of a
pilot-channel phase-angle-detecting relaying-sys
limited magnitude which is insufficient to cause
tem adapted to protect a section of a three-phase
any material operative conduction of the tube in
the absence of a positive sequence-responsive pul
transmission-line against faults, comprising cur
50 rent-responsive voltage-developing means opera
sating voltage.,
tive to develop a pulsating voltage having a phase
13. The invention as deñned in claim 9, char
acterized by said non-pulsatory voltage having a
which is responsive to a function of the three
limited magnitude which is insuflicient to cause
phase line-current at said terminal, ground-fault
detector-means for selectively responding to
any material operative conduction of the tube in
55 ground-fault line-conditions more sensitively
the absence of a single-phase voltage.
i4. Terminal equipment for one terminal of a
pilot-channel phase-angle-detecting relaying
than said current-responsive voltage-developing
means, said ground-fault detector-means being
operative to provide a unidirectional voltage of
substantially non-pulsatory form, a tube, means
60 for normally providing a tube-circuit voltage
operative to develop a pulsating voltage having a
which prevents the tube from becoming effec
phase which is responsive to a function of the
tively conductive, means for making said uni
directional voltage effective in a circuit or" said
three-phase line-current at said terminal, ground
tube in the polarity tending to make the tube
fault detector-means for selectively responding to
ground-fault line-conditions more sensitively
become effectively conductive, means for making
than said current-responsive voltage-developing
said pulsating voltage effective in a circuit of said
tube in such manner as to tend to cause the tube
means, means controlled by said ground-fault de
tector-means for making said current-responsive
to be operatively conductive on alternate half
voltage-developing means respond more sensitive
cycles of the line-current frequency in response
to the pulsations of said pulsating voltage, local
1y to said function of the three-phase line-cur
rent, local control-means operative to develop a
control-means responsive to said tube for de
veloping a succession of operating impulses dur
succession of operating impulses in response to
system adapted to protect a section of a three
phase transmission-line against faults, compris
ing current-responsive voltage-developing means
positive half-cycles of said pulsating voltage,
pilot-channel means operative to transmit a suc
ing alternate half-cycles of said pulsating volt
age, pilot-channel means responsive to said tube
cession of restraining impulses and to make them 75 for transmitting a succession of restraining im
19
20
pulses and making them effective at another line
single-phase voltage, local control-means respon
terminal or terminals during the other half
sive to the operation of one tube for developing
a succession of operating impulses, pilot-channel
means responsive to the operation of the other
tube for transmitting a succession of restraining
impulses and making them effective at another
line-terminal or terminals, and phase-angle-de
tecting relay-means operative to respond to said
operating impulses when they are not effectively
opposed by restraining impulses received from a
distant line-terminal.
cycles of said pulsating voltage, and phase-angle
detecting relay-means operative to respond to
said operating impulses when they are not effec
tively opposed by restraining impulses received
from a distant line-terminal.
18. Terminal equipment for one terminal of a
pilot-channel phase-angle-detecting
relaying
system adapted to protect a section of a three
phase transmission-line against faults, compris
ing current-responsive voltage-developing means
operative to develop a single-phase voltage hav
20. Terminal equipment for one terminal of a
pilot-channel phase-angle-detecting relaying sys
ing a phase which is responsive to a function of
tem adapted to protect a section of a three-phase
the three-phase line-current at said terminal,
ground-fault detector-means for selectively re
sponding to ground-fault line-conditions more
sensitively than said current-responsive voltage
developingr means, said ground-fault detector
transmission-line against faults, comprising
phase-sequence means for developing two differ
ent single-phase control-voltages in response to
two different phase-sequence functions of the
line-current at the relaying terminal, local con
means being operative to provide a unidirectional
trol-means responsive to a ñrst one of said con
trol-voltages for producing a succession of re
voltage of substantially non-pulsatory form, elec
tronic apparatus comprisingl two tubes, means for
making said single-phase voltage effective in cir
cuits of the two tubes in such manner as to tend to
cause one tube to be operatively conductive on
positive half-cycles of said single-phase voltage
and to. tend to cause the other tube to be op
eratively conductive on negative half-cycles of
said single-phase voltage, means for making said
unidirectional voltage eiîective in circuits of said
tubes in a polarity facilitating the operative con
ductivity of said tubes, local control-means re
sponsive to the operation of one tube for develop
ing a succession of operating impulses, pilot
channel means responsive to the operation of the
other tube for transmitting a succession of re
straining impulses in response to negative half
cycles of said ñrst control-voltage when said
control-voltage exceeds a predetermined magni
tude, and for producing a succession of operating
impulses in response to positive half-cycles of
said ñrst control-voltage when said control-volt
age exceeds a predetermined magnitude, means
responsive to the second control-voltage for in
creasing the sensitiveness of the response of said
local control-means to said first control-voltage,
fault-detector means for responding to locally
detectable fault-conditions on the transmission
line, means for utilizing said fault-detector means
in controlling said local control-means, pilot
channel means operative to transmit said suc
fectively opposed by restraining impulses received
cession of restraining impulses and to make them
effective at another line-terminal or terminals,
and phase-angle-detecting relay-means opera
tive to respond to said operating impulses when
they are not effectively opposed by restraining
from a distant line-terminal.
19. Terminal equipment for one terminal of a
impulses received from a distant line-terminal.
21. Terminal equipment for one terminal of a
straining impulses and making them effective at
another line-terminal or terminals, and phase
angle-detecting relay-means operative to respond
to said operating impulses when they are not ef 40
pilot-channel phase-angle-detecting
relaying
system adapted to protect a section of a three
phase transmission-line against faults, compris
ing current-responsive voltage-developing means
operative to develop a single-phase voltage hav
ing a phase which is responsive to a function of
the three-phase line-current at said terminal, "t"
ground-fault detector-means for selectively re
sponding to ground-fault line-conditions more
sensitively than said current-responsive voltage
developing means, said ground-fault detector
means being operative to provide a unidirectional
voltage of substantially non-pulsatory form, elec
pilot-channel
phase-angle-detecting
relaying
system adapted to protect a section of a three
phase transmission-line against faults, compris
ing phase-sequence means for developing a single
phase control-voltage in response to a phase-se
quence function of the line-current at the relay
ing terminal, local control-means responsive to
said control-voltage for producing a succession of
restraining impulses in response to negative half
cycles of said control-Voltage when said control
voltage exceeds a predetermined magnitude, and
for producing a succession of operating impulses
in response to positive half-cycles of said control
voltage when said control-voltage exceeds a pre
determined magnitude, fault-detector means for
selectively responding to a locally detectable
fault-condition other than a balanced three-phase
tronic apparatus comprising two tubes, each hav
ing control-circuit means, supply-leads adapted
to provide a direct-current plate-voltage supply
circuit for each tube, means for normally pro
fault Orr the transmission-line, means for utiliz
viding each tube with a control-circuit voltage
ing said fault-detector means to increase the
which prevents the tube from becoming effec
sensitivity of response of said local control
tively conductive, means for making said unidi
means, pilot-channel means operative to trans
rectional voltage effective in circuits of said tubes
in the polarity tending to make the tube become 65 mit said succession of restraining impulses and
to make them 4effective at another line-terminal
effectively conducting, means for making said
or terminals, and phase-angle-detecting relay
single-phase voltage oppositely effective in cir
means operative to respond to said operating im
cuits of the two tubes in such manner as to tend
pulses when they are not eifectively opposed by
to cause one tube of be operatively conductive on
positive half-cycles of said single-phase voltage 70 restraining impulses received from a distant line
and to tend to cause the other tube to be oper
atively conductive on negative half-cycles of said
terminal.
HERBERT W. LENSNER.
Документ
Категория
Без категории
Просмотров
0
Размер файла
1 964 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа