Improvements in and relating to the Distribution of Electrical Energy.
Year: 1893

page_text: Date of Application, 18th Feb., 1893
Complete Specification Left, 20th Nov., 1893-Accepted, 17th Feb., 1894
PROVISIONAL SPECIFICATION.
Improvements in and relating to the Distribution of Electrical
Energy.
WILLIAM LOWRIE of 117 Bishopsgate Street Within London E.C. Engineer.
I do hereby declare the nature of this invention to be as follows:-
My invention relates to the distribution of electricity by the parallel converter
system whether with continuous alternating or undulatory currents.
Any type of converters suitable for the different currents may be used.
The difficulties hitherto with the parallel converter system have been the losses
due to the magnetizing current, and friction going on wheu no useful work was
being done in the secondary circuits. Sub-stations and the method of banking
converters (so that the number of converters kept in action may be only sufficient
to supply the electricity demand) have been used to overcome the losses, but a
secondary system of distribution by these plans become necessary over the whole
area of supply, & the cost of this secondary system and the staff required at each
of the sub-stations, take away the advantages derived from the high tension
primary distribution used with the parallel converter system.
By my invention 1 place the converters at intervals in the roads of the area to
be supplied in road boxes or chambers formed in the road or premises to be
supplied and connect the primary windings of the converters alternately to
separate mains coming direct from the switch-board, at the generating station, or
other suitable positions. Instead of 2 sets of cables many may be used and the
converters so arranged that any converter or groups of converters can be cut out
by suitable switching apparatus at the central station or sub-stations. Having
thus control of the primary supply over the area it is necessary also to control the
secondary circuits so that on cutting out any converter or group of converters the
work on their secondary circuits is taken up by the others in action. This I
propose to do by a secondary compensating system of mains. This compensating
cable or cables connects together terminal bars fixed near the terminals of the
secondary winding of each of the converters. When the primary of any con-
verter is put in action an automatic device will put the secondary terminals in
connection with the compensating circuit: to this compensating circuit all the
supply wires are joined. By this system only the converter power required need
be in action as any converter or group of converters can be put on or off the
compensating system by the switching apparatus at the central station...
The primary circuits may have a common return.
L
**
The secondary automatic switch may be worked by a shunt across the secondary
terminals or across the primary terminals or may be in series with the primary
winding or any other well known method.
The compensating circuit may be only of sufficient section to carry electricity for
the lightest part of the day load.
The house connections may be made direct from the road boxes or sub-stations,
thus no conductors would be placed in position until required for actual use.
>
On first installing a parallel converter system over an area of supply, a set. of
small pilot cables may be run and form a complete net work over the area and
permanent cables can afterwards be installed over the best route when
required and as proved by the pilot cable, these permanent cables will take over
the work from the pilot system leaving it to take up new business at any point in
the area.

page_text: It will be seen that besides the secondary windings of the converters being
automatically connected by switching on the primary current, that on switching
off the primary current the rush of current back through the secondary winding
and the shunt will disconnect the secondary winding from the compensating wire
and also if the automatic device fails to close the secondary circuit the lights will
not be extinguised, or if it fails to open it only a small current will pass through
the secondary winding due to self induction.
The switching may be done either by hand or any suitable automatic gear.
"Dated 18th February 1893.
ענעםU
Improvements in and relating to the Distribution of Electrical
Energy.
I, WILLIAM LOWRIE, of 117 Bishopsgate Street Within, in the City of
London, 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 :-
My invention relates to the distribution of electricity by what is known as
the parallel converter system, and in which continuous, alternating, or undulatory
currents may be used; it being understood that the converters (or transformers)
employed, are of the kind suitable for the particular kind of current which is
distributed.
The difficulties hitherto met with in the parallel converter system have been
the loss arising from the magnetizing current, and-in the case of motor converters
(or transformers) used in connection with continuous currents-frictional loss,
incurred while little or no useful work was being done in the secondary circuits.
A system of sub-stations and banked converters (so that the number of converters
in action may be only sufficient to supply the demand for electricity) has been
used to overcome the said losses, but-by this plan-a secondary system of
distribution became necessary over the whole supply area, and the cost of this
system, and of the staff required at the sub-stations detract from the advantages of
high tension primary distribution to the parallel converter system.
By my invention I place converters at intervals in the roads of the area to be
supplied within road boxes, or chambers, or premises supplied, and connect the
primary.windings of the said converters alternately to two or more separate mains
or conductors coming direct from a switch board at the generating station, or
other suitable place. The converters are so arranged upon the said mains that a
converter or group of converters can be cut out by suitable switching apparatus
at the central or other station. Having thus control of the primary supply over
the area, it is also necessary to control the secondary circuits, so that on cutting
out a converter or group thereof, the work on their secondary circuits is taken up
by the converters left in action. This I do by a secondary compensating or
distributing system of mains, consisting of a cable or cables connecting together
terminal bars fixed near the secondary terminals of each converter. When the
primary of any converter is put in action, an automatic device will put the secondary
terminals in connection with the compensating or distributing circuit; and to this
compensating or distributing circuit all the supply wires are joined. By this
system, only the required converter power or capacity need be in action at a time
of low load, as any particular group of one or more converters can be switched. on
from the station as the load increases; while, conversely, the several groups may
be successively cut out as the load diminishes." . . I "
• .
The primary circuits may have a common return. The secondary automatic
switch may be worked by a shunt across the secondary terminals, or across the

page_text: primary terminals, or be in series with the primary or secondary windings, or
combinations thereof.
It is to be noted that while the secondary windings of converters are automatically
connected by the switching on of the primary current, the switching off of the
primary current is made to disconnect the secondary winding from the compensating
or distributing system of mains by the rush of current back through the secondary
windings and shunt; if a shunt be used. The primary switching may be done
either by hand, or by any suitable automatic gear.
The compensating or distributing circuit need only have a sufficient sectional
area to conduct the electrical energy for extreme low load.
In the accompanying drawings,
Fig. 1 is a diagram indicating my arrangement for distributing electrical energy
derived from alternating currents; and Fig. 2 the same, but adapted for continuous
or direct currents, instead of alternating.
,
In these diagrams A, A' indicates the omnibus or feed bars, in a central or other
station, fed by two or more generators, a, a¹. Two or more separate mains B, B';
and B3, B³, are connected directly to the switch board or bars A, A', at the
station, and thence are connected alternately to the primary windings b, b¹,
and of two or more converters C and C. The secondary windings c, c¹,
and c, cof the said converters are connected to the distributing system of
mains D, D', which connect together the secondary terminals d, d, of the converters.
To the mains D, D', all the supply wires (not shown) are joined, so that the
said mains D, D₁, act as a compensating circuit between the converters throughout
the district supplied.
When the primary circuit B (for example) is put in action from the station,
an automatic device E is used to put the secondary terminals d, d, of the
converter C, in connection with the compensating or distributing mains D, D¹, and
BO on to all the supply wires joined to the circuit D, D'. If the load increases,
the second converter shown (C') is similarly put into action from the station
through the primary circuit B2, B3; and the same method is employed with other
converters that are on the circuit D, D. Each converter shown in the drawings
is intended to represent either a single converter or a group of converters fed by a
separate main or conductor whatever may be the number of converters in the
group. But in practice all these separate mains or conductors may be conveniently
laid close to, but insulated from, each other; so that the primary current may be
operating in one pair of conductors, and not in another pair adjoining.
When the load is reduced, and it is required to cut out a group of one or more
converters, the switching off, or breaking, of the primary circuit, at the station
by the ordinary switch F, (or F¹), is made to disconnect the secondary
winding c, c', (for example) from the compensating or distributing system D, D',
by the rush of current back through the secondary winding and shunt; as indicated.
at E of the converter C. This secondary automatic switch E may be worked by
a shunt across the secondary terminals, or across the primary terminals, or other-
wise as already stated; and I do not confine myself to the exact form of automatic
switch used for this purpose so long as it performs the functions required. But
as many have tried to solve this problem, it is necessary to state that I have
found it is not sufficient to simply break the primary circuit (B, B' for example)-
as suggested by some electrical engineers-so long as the distributing circuit is
charged; for the current therefrom, circulating through the secondary winding e, c¹,
(for example), would reversely and inductively affect the primary winding b, b.
Therefore, any cut out switch in the secondary circuit of a converter-depending
for its breaking action upon an armature or core being automatically dropped on
the mere breaking of the primary circuit at the station-will not act; as the back
action of the current through the secondary will have an inmediate and equivalent
magnetic action to that of the primary current upon the armature or core; and
the cut out switch fails to act. Consequently, it is necessary to make aud break
both primary and secondary circuits together, the primary being operated upon at

page_text: the station, while the secondary is operated upon at the converter by means of the
current coming from the secondary circuit. It is to be understood that the above
remarks do not apply where the secondary circuit receives electric energy only
through a single primary circuit, or where all the primary circuits are broken
together, for in such cases the secondary circuit or circuits would cease with the
cessation of the primary current; but this plan would not provide for a continuous
supply and economy in the magnetizing current when the load is small, and
therefore does not come within the purview of this invention.
ر
In my application for Letters Patent dated the 18th day of November 1893,
and No. 22131, I have described the details of an automatic switching apparatus
suitable for use in carrying out this invention and for some other purposes not
described herein; but as aforesaid, I do not confine myself to the exact form of
switch used to carry out the purpose of this invention, so long as it performs the
functions herein described; and I would have it understood that I have used
drawings in the said application similar to those accompanying this Specification,
but that I do not claim hereby anything claimed in the Specification to the
aforesaid Specification, No. 22131 of 1893.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is ;-
1. In a parallel converter system of distributing electrical energy, the combina-
tion of a switch at the station, a separate main or conductor leading therefrom
to the primary winding or windings of a converter or group thereof, a distributing
system of mains connected to the secondary terminals of the said converter or
converters, and an automatic switching apparatus placed in the secondary circuit
and operating to put the said secondary terminals in connection with the said
distributing system of mains when the primary circuit is put in action at the
station, and to put the said secondary terminals out of connection with the
distributing system, when the primary circuit is put out of action at the station,
substantially as herein described.
2. In a system of distributing electrical energy, the combination of two or more
separate mains or conductors, two or more groups of converters, each group (of
one or more converters) having its primary winding or windings connected to a
separate main or conductor, means at the station for putting each separate main in
or out of action separately, and an automatic switching apparatus placed in the
secondary circuit of each converter of each group and operating to put the same
in and out of connection with a distributing system of mains (charged with
current) when the primary circuit of the corresponding group is put in or out of
action at the station, substantially as and for the purpose herein described.
Dated this 18th day of November 1893.
FAIRFAX & WETTER,
433, Strand, London, Agents for the Applicant.