Improvements in or relating to Systems of Electrical Distribution.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in or relating to Systems of Electrical Distribution.
I, LEONARD ANDREWS, of 20, South Terrace, Hastings, in the County of Sussex,
Electrical Engineer, do hereby declare the nature of this invention to be as
follows:-
In electrical distributing systems in which electrical energy is distributed from
a central station to substations or distributing points (hereinafter called sub-
stations) by means of feeders it has heretofore been common to provide the feeders
with hand operated switches and to interconnect the substations by conductors
so that any feeder may be temporarily cut out for repair or other purpose without
interrupting the supply of electricity to the substation to which it is connected.
Where feeders and substations are arranged in this manner it is usual to insert
an excess current cut out such as a safety fuse, or magnetic or other excess
current cut out at each end of each feeder ciz. where it leaves the generating
station and where it is connected to the substation so that, should a short circuit
occur on any feeder, the safety devices at its extremities will immediately cut it
out of circuit. It not unfrequently happens however, that the cut outs in a
healthy feeder will operate before the cut out at the distributing end of the faulty
feeder, owing to the fact that the healthy feeder has to carry sufficient current to
operate the faulty feeders cut out in addition to the useful work normally supplied
by both feeders with the result that the supply of electricity to the district fed
by the two feeders will be interfered with.
Now this invention has for object to obviate this great disadvantage. For
this purpose I provide in connection with the outgoing and return feeders near
to their points of connection with each substation automatic cut out apparatus
so constructed and arranged that it will carry as heavy a current as the feeders
so long as the electric energy is being supplied from the generating station to
the distributing station, but will cut out with a comparatively small current
returning towards the generating station the construction of the cut out apparatus
moreover being such that interruption in the supply of energy from the generating
station will have no action on the cut out apparatus. The main feeders between
the generating stations and substations and also it may be those between the
substations, are provided as usual with excess current cut outs at points near
where they pass outwards from the generating and substations. Apparatus to
operate in the manner described comprises a movable switch or cut out device
arranged in the main feeder and controlled by an electro-magnetic device com-
prising a series coil or coils arranged in circuit with the main feeder, a shunt-coil
or coils connected across the main feeder and return near to the substation, a
magnetic core or cores, and operating mechanism between the core or cores and
the switch or cut out device, the series and shunt coils being so proportioned and
arranged that the core or cores will not act to open the feeder circuit so long as
current below, at or above the normal amount is being supplied from the
generating station, nor when the supply of current is cut off, but will act to open

page_text: the switch or cut out in the event of current being supplied in the reverse direction
viz. from the substation to the main feeder, as would be the case should a fault
occur in such feeder between the generating and substations.
I arrange the coils and core or cores in such a way that a forward magnetic pull
is exerted in one direction with a current supplied from the generating station
and a backward magnetic pull with a current supplied from the substation to the
feeder to which the coils are connected so that nothing but an actual flow of
current through the electro magnetic device in the reverse direction to that
required for supply purposes will cause the switch or cut out to be operated so
as to disconnect the feeder from the substation. Apparatus to operate in the
manner described can be constructed in various forms.
According to one arrangement such apparatus consists of a compound wound
magnetic device comprising two distinct windings and one or more iron cores
one of the windings being connected in series with one of the feeders and the
other connected as a shunt across the feeders and the movable core or cores being
mechanically connected to a catch device for releasing a weight or spring for
operating the switch or cut out. The two windings are so arranged relatively
to each other, that their combined influence upon the iron core or cores tends to
move it or them in one direction, with a forward current, and in the reverse
direction with a return current. When the current in the feeders is flowing in
its normal direction the movement of the core or cores tends to securely lock
the catch in position but when the series current is reversed relatively to the
current in the shunt then the movement of the core or cores tends to release the
catch and open the switch or cut out.
In one construction of this kind one of the windings is wound around a core
mounted to turn about a centre and is so disposed in relation to the other winding
and the core as to constitute in effect a shunt motor that will turn
or tend to
turn in one direction for a direct current and in the reverse direction for a
return current and in the latter case act to open the switch or cut out with which
it is used as hereinbefore explained.
In speaking of the direction of current I do not intend to exclude alternate
currents but have described the invention for simplicity with direct current
examples. I apply my invention in the case of alternate current working by
making the apparatus according to the principles well understood by which
although the currents are alternating the simultaneous directions of the currents
act relatively as described with reference to direct currents.
Improvements in or relating to Systems of Electrical Distribution.
I, LEONARD ANDREWS, of 20, South Terrace, Hastings, in the County of Sussex,
Electrical Engineer, do hereby declare the nature of this invention and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement:-
In electrical distributing systems in which electrical energy is distributed from
a central station to substations or distributing points (hereinafter called sub

page_text: stations) by means of feeders it has heretofore been common to provide the feeders
with hand operated switches and to interconnect the substations by conductors
so that any feeder may be temporarily cut out for repair or other purpose
without
interrupting the supply of electricity to the substation to which it is connected.
Where feeders and substations are arranged in this manner it is usual to insert
an excess current cut-out, such as a safety fuse, or magnetic or other excess
current cut-out at each end of each feeder, viz. where it leaves the generating
station and where it is connected to the substation so that, should a short circuit
occur on any feeder, the safety devices at its extremities will immediately cut it
out of circuit. It not unfrequently happens however, that the cut-outs in a
healthy feeder will operate before the cut-out at the distributing end of the faulty
feeder, owing to the fact that the healthy feeder has to carry sufficient current to
operate the faulty feeder's cut-out in addition to the useful work normally supplied
by both feeders, with the result that the supply of electricity to the district fed
by the two feeders will be interfered with.
Now this invention has for object to obviate this great disadvantage. For
this purpose I provide in connection with the outgoing and return feeders near
to their points of connection with each substation, automatic cut-out apparatus
so constructed and arranged that it will carry as heavy a current as the feeders
so long as the electric energy is being supplied from the generating station to
the distributing station, but will cut out with a comparatively small current
returning towards the generating station, the construction of the cut-out apparatus
moreover being such that interruption in the supply of energy from the generating
station will have no action on the cut-out apparatus. The main feeders between
the generating stations and substations, and also it may be those between the
substations, are provided as usual with excess current cut-outs at points near
where they pass outwards from the generating and substations. Apparatus to
operate in the manner described comprises a movable switch or cut-out device
arranged in the main feeder and controlled by an electro-magnetic device com-
prising a series coil or coils arranged in circuit with the main feeder, a shunt-coil
or coils connected across the main feeder and return near to the substation, a
magnetic core or cores, and operating mechanism between the core or cores and
the switch or cut-out device, the series and shunt coils being so proportioned and
arranged that the core or cores will not act to open the feeder circuit so long as
current below, at or above the normal amount is being supplied from the
generating station, nor when the supply of current is cut off, but will act to open
the switch or cut-out in the event of current being supplied in the reverse direction
viz. from the substation to the main feeder, as would be the case should a fault
occur in such feeder between the generating and substations. The coils and
core or cores are arranged in such a way that a forward magnetic pull is
exerted in one direction with a current supplied from the generating station,
and a backward magnetic pull with a current supplied from the substation to the
feeder to which the coils are connected, so that nothing but an actual flow of
current through the electro magnetic device in the reverse direction to that
required for supply purposes, will cause the switch or cut-out to be operated so
as to disconnect the feeder from the substation. Consequently a fault in one
feeder will not cause the cut-out or cut-outs of a healthy feeder, which will then
be called upon to supply current to the sub-station normally supplied by the
faulty feeder, to open the circuit of such healthy feeder and interfere with the
electric supply.
Apparatus to operate in the manner described can be constructed in various
forms.
According to one arrangement, such apparatus consists of a compound wound
magnetic device comprising two distinct windings and one or more iron cores.
one of the windings being connected in series with one of the feeders and the
other connected as a shunt across the feeders, and the movable core or cores being
mechanically connected to a catch device for releasing a weight or spring for

page_text: operating the switch or cut-out. The two windings are so arranged relatively
to each other, that their combined influence upon the iron core or cores tends to
move it or them in one direction with a forward current, and in the reverse
direction with a return current. When the current in the feeders is flowing in
its normal direction, the movement of the core or cores tends to securely lock
the catch in position, but when the series current is reversed relatively to the
current in the shunt, then the movement of the core or cores tends to release the
catch and open the switch or cut-out.
In one construction of this kind one of the windings is wound around a core
mounted to turn about a centre and is so disposed in relation to the other winding
and the core as to constitute in effect a shunt motor that will turn, or tend to
turn, in one direction for a direct current, and in the reverse direction for a
return current and in the latter case act to open the switch or cut-out with which
it is used, as herein before explained.
In speaking of the direction of current I do not intend to exclude alternate
currents but have described the invention for simplicity with direct current
examples. I apply my invention in the case of alternate current working by
making the apparatus according to the principles well understood by which
although the currents are alternating, the simultaneous directions of the currents
act relatively as described with reference to direct currents.
Fig. 1 of the accompanying drawings is a diagram showing a high tension
electrical distributing system comprising a central generating station connected
to interconnected sub-stations by feeders provided with automatic cut-out appar-
atus according to this invention.
1 is the central generating station connected by main feeders 2 to transformer
sub-stations 3 which are interconnected by auxiliary feeders or conductors 4 by
means of which any one of the feeders 2 connected to such interconnected sub-
stations can be temporarily cut-out of action for repair or other purpose without
interrupting the supply of electricity to the sub-station to which it was directly
connected, such substation then receiving its supply of electricity through the
auxiliary feeder 4 connecting it with another sub-station. 2 and 4" are the return
leads of the main and auxiliary feeders respectively. In an alternating current
system, the mains 2, 2 and also 4, 4ª are of course each alternately positive and
negative feeders. 2b and 4b indicate ordinary excess current cut-outs, such as
safety fuses or magnetic or other excess current cut-outs arranged at the ends of
the main and auxiliary feeders 2 and 4 where they leave the central generating
station 1 and substations 3. Each substation in this case comprises one or more
transforming devices 3* for supplying electrical energy to local circuits 3ª, 3b. In
a continuous current system of distribution the transforming devices may be of
the kind known as motor-transformers, each consisting of a combined motor and
dynamo; in an alternating current system of distribution, such as shown in Fig. 1,
the said transforming devices may be ordinary induction transformers having
primary and secondary windings.
The automatic return current cut-outs arranged in connection with the
feeders 2, 2ª near to their points of connection with each sub-station as herein-
before described, are indicated diagrammatically at each substation. Each of
these cut-outs comprises a movable switch or contact 5 that is provided with a
weighted arm or lever 5", is adapted to engage with fixed contacts 6, 6 connected
to the adjacent parts of the main feeder 2, and is controlled by an electro-magnetic
device comprising a field magnet 7 made in the form of a bent iron core provided
with a series winding 8 and between the polar ends of which a rotary armature
core 9 provided with a shunt winding 10 is so pivoted that the normal position of
its field is approximately at right angles to the field produced by the series
winding, the armature in this position acting through a catch device 5b, formed
in the example shown by the free end of the switch arm or lever 5ª, to normally
hold the said arm or lever in the raised position and the switch 5 in the closed
position. This position of the armature is insured when no current is flowing

page_text: through the cut-out device, by loading the armature by means of a spring or
weight so that it normally bears against a fixed stop 11.
The winding 8 is arranged in series with the feeder 2. The shunt winding 10
may be connected as a shunt across the feeders 2, 2" as shown, in dotted lines,
or across the distributing mains 3", 3b, fed from such feeders, as indicated in full
lines. In the former case the shunt winding may be connected to the secondary
winding of a transformer the primary winding of which is connected as a shunt
across the feeders 2, 2". These different arrangements are electrically the equi-
valent of one another for the purpose required.
As will be seen the arrangement is such that when current is being supplied
from the generating station to the substations, the direction of the currents through
the series and shunt windings of each cut-out device at a given moment, will be
represented by the arrow heads shown in full lines and the polarity of the field
magnet poles and armature poles by the letters N and S thereon, the relative
direction of the currents in the shunt and series windings being such as to tend
to cause the armature to rotate in a clockwise direction against the stop 11 and
so to securely lock the switch 4 in the closed position, in which position it will
also be maintained when no current is flowing through the main feeder and
cut out device. If however either of the main feeders 2 should become short
circuited, current will be supplied to it from the corresponding substation in
the direction of the generating station and will flow through the series winding
of the cut-out device in the opposite direction, or that shown by the dotted arrows,
whereas the direction of the current in the shunt winding will remain unchanged.
As in this case the direction of the series current relatively to that of the shunt
current will be reversed, the armature will rotate in a counter clockwise direction
and release the weighted switch lever 5" which will immediately fall and by
opening the switch 5 disconnect the main faulty feeder from the substation.
The induction of the shunt circuit must be carefully adjusted to produce the
requisite lag in phase of the shunt current, necessary to obtain the greatest torque
between the two magnetic fields at the time when the armature is required to
release the loaded switch.
Fig. 2 shows, diagrammatically, a low tension system of electrical distribution
provided with return current cut outs according to this invention. In this case
each pair of main feeders 2, 2ª from the generating station 1 extends to one or
more substations 3 from which extend the distributing mains or local circuits 3ª, 3b
which contain lamps or other translating devices 3° and which are connected
direct to the feeders 2, 2" without the intervention of electric transformers. Some
of the distributing mains, such as those marked 3, 3, may connect the main
feeders 2, 2ª of different substations and thus be available for use as auxiliary
feeders, as and for the purpose herein before described. The return current cut-outs
shown, are like those hereinbefore described with reference to Fig. 1 and act in
the same way,
In carrying out the invention I prefer to employ a magnetic return current
cut-out of the kind shown in Fig. 3 according to which the weighted switch arm
or lever 5 is normally prevented from falling and opening the switch 5 by a
pivoted catch lever 5 which is held in the locking position by a pin 9" carried
by a plate 9b that is connected to the armature of a shunt motor of the kind
herein before described and is normally held against the stop 11 by a spring or
weight. The pin 9ª engages the free end of the catch lever 5b in such a way
that the direction of pressure between the pin 9" and the contact surface 5° of
the said lever against which it bears, is located in an arc 12 that has its centre
at the axis of the said catch lever and passes through the axis of the plate 9b and
the contact surface 5° is concentric to the axis of the plate. By this special
construction of cut-out, for which I have filed a separate Application for Letters
5 Patent, No. 3496 of 1898, no amount of pressure on the switch arm will tend to
rotate the plate 9b in either direction, but the plate can be electrically rotated
in the direction of the arrow, so as to release the switch arm or lever 5ª, without

page_text: having to lift or do any work on such arm or lever, so that whilst the cut-out
will be very effective and reliable, it will at the same time be very sensitive to
the action of a return current.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is:-
:--
1. In electrical distributing systems of the kind herein referred to, providing
the main feeders near to their points of connection with distributing or sub-
stations, with automatic cut-out apparatus each of which is so constructed and
arranged as to keep the corresponding feeder circuit closed so long as electrical
energy is being supplied from the generating station to the distributing or sub-
station, and also when no current traverses the feeder circuit, but will act to open
the feeder circuit when traversed by a current returning towards the generating
station, as set forth.
2. In electrical distributing systems of the kind herein referred to, the combina-
tion with the main feeders of automatic return current cut-out apparatus con-
structed arranged and operating substantially as described and shown for the
purposes specified.
Dated this 15th day of September 1898.
For the Applicant,
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C.,
Chartered Patent Agent.