Note: Descriptions are shown in the official language in which they were submitted.
116S416
COUP~ING UNI~ FOR CONNECTION OF HIGH~VO~TAGE GElYERA-
~OR WINDING LEAD-OU~ ~ND CABLE.
The present invention relates to elec-trical industry
and, in particular, to cable couplings and specifically to
a coupling unit for connection of a lead-out of a high-
-voltage generator winding and a cable~
The invention can be used in manufacturing high-power
generators, including turbo generators, for thermal and nu-
clear power plants and heavy-duty transformers.
Modern electrical engineerlng tend~to use higher
voltage in power transmission lines, transformers and ge-
nerators in an attempt to increase their e~ficiency and
minimize their dimensions.
However, the use of high and superhigh.~voltages brings
in the problem of designing coupling units for connection
of various electrical elements, for eæample units to couple
high-voltage cables to aerial lines or cable lead-in9.f~r
trans~ormers.
One way of coupling a high-voltage generator to other
electrical devices consists in connecting an oil-filled
~ ~ cable of a high-voltage generator stator winding to an oil-
: -filled cable joining the high-voltage generator to a high-
. _voltage station or line.
The closest prototype of the present invention is a
: coupling unit for connection of a lead-out o~ a high-vol-
tage generator wi~ding and a cable linking said lead to
- 1 -
. ~
1165416
external elec-trical apparatuses, which is made as a cable
joint box /V.A.Priveze~sev, E.P. ~arina, Power Cables and
High-Voltage Cable Lines. 1970, ~nergia Publ., Moscow,
pp.72-73, 77-79. (in Russian)/.
The known coupling unit comprises a casing ~illed
with a~ insulating substance, for example oil, wherein
the cable termination ~eaturing a capacitor splice and the
lead-out of the generator high-voltage winding, featuring
sheaths and a capacitor splice, are ~rrangeà~ the curren-t-
-carrying elements thereof being coupled to one another,
both the lead-out of the generator high-voltage winding
and the cable termination being encased into an insulating
hermeticall~ sealed coàting.
~ he known coupli~g unit is characterized by irregular
distribution of voltage throughout the surface o~ the
splice of the cable termination which is depe~dent upon
the capacitance between the plates of said capacitor spli-
ce and upon the capacitance between the plates of the
cable termination splice and the casing.
Irregular distribution of voltage throughout the sur-
~ace o~ the capacitor splicing of the cable termination
may result in rupture of insulation whereever the inten-
sity o~ the electrical field is the greatest. The capacitor
splicing of the cable termination is made very long in
order to eliminate the possibility of such ruptures in
the known coupling unit ~or connection o~ the high-voltage
- 2 -
116~416
generator winding and the cable, which makes the unit
bulky.
It is an object of the present inve~ion to provide
a more compact coupling unit for connection of a generator
high-voltage winding lead-out ~ld a cable joining the ge-
nerator to external electrical apparatuses.
Another object of` the invention is to provide a more
reliable coupling unit for connection o~ a generator high-
-voltage winding lead-out and a cable aoining this genera-
tor to external elec-trical apparatuses.
The invention essentially resides in -tha-t in a coup-
ling unit for connection of a generator high-voltage wind-
ing lead-out and a cable, comprising a casing filled with
an insulation substance and accomodating a cable terminati-
on with a capacitor splice and a lead-out of a generator
high-voltage winding, featuring sheaths and a capacitor
splice, whose current carrying elements are connected to
one another, the lead-out of the generator high-voltage
winding being encased into an insulating hermetically sealed
coating, according to the in~ention, the sheaths of the ge-
nerator high-voltage winding lead-out are made as a system
of concentric cylinders, which form at the edge of the lead-
-out a capacitor splice, contact rings being arranged on
the surface of the capacitor splice of the generator high-
-voltage winding lead-out at a certain distance Prom one
another, each such ring being connected to its sheath of
the generator high-~oltage winding lead-out, which has a
-- 3 --
116~16
specific electric potential, whereas the plates of -the
capacitor splice of the cable termination are connected to
its con~ac-t ring~s arranged on the surface of the ca~acitor
splice o~ the cable termination, each contact ring located
on the capacitor splice of the generator high-voltage
winding lead-out in the plane parallel to the plane extending
through the beginning of this capacitor splice and at a
specific ~niform distance between said planes being joined
by means of a strap to a contact ring located on the capa-
citor splice of the cable termination in the plane paral-
lel to the plane extending through the beginning of the
capacitor splice o~ the cable termination and at the same
specific distance ~etween latter planes, whereas the cur-
rent car~ying elements of the ~enerator high-voltage wind-
ing lead-out and the cable termination are linked by means
of a power jumper.
~ he use of the invention permits significant reducti-
on of the dimensions o~ the coupling unit ~or connection
of a generator high-voltage winding lead-out and a cable
and, consequently, manufacture of high-power generators
with a stator winding voltage of up to 500 kV. Besides,
the use of the invention permits a substantial incLease in
the operational reli~ity of the coupling unit for con-
nection of a generator high-voltage winding lead-out and
a cable, as well as o~ the generator as a whole through
a more effective voltage compensation throughout the
surface of the capacitor splice of the cable termination.
'
llS5416
Given herein below is a detailed description o~ an
exemplaI~ embodiment o~ the present invention, reference
being had to the accompanying drawing illustrating a lon-
~itudinal section view of a coupling unit for connection
of a generator high-voltage winding lead-out and a cable
joiniDg the generator to external electrical apparatuses,
according to the invention.
A coupling unit for connection of a generator high-
-voltage winding lead-out and a cable joining -the generator
to external electrical apparatuses comprises a casing 1
filled with an insulation substance, for example insulating
oil 2. The casing 1 accomodates a termination 3 of the cab-
le joini~g the generator to external electrical apparatu-
ses~ featuring a capacitor splice 4 and a lead-out 5 of
the generator high-voltage winding, featuring sheaths 6
and a capacitor splice 7. The sheaths ~ of the lead-out 5
of the generator high-voltage winding are a system of con-
centric cylinders which form at the edge thereof the ca-
pacitor splice 7. A capacitor splice here means the fa~ned
out bell end of the cable insulation, which forms a cone
of insulation layers alternating with conducting layers,
the tip of the cone being the core of the current carrying
wire of the cable. Current carrying elements 8 of the -ter-
mination 3 and of the lead-out 5 are linked b~ means of
a jumper 9. The lead-out 5 of the generator high-voltage
winding is encased into an insulating tight coating 10
which is intended for separation of the oil systems of the
generator high-voltage winding lead-out and the cable.
-- 5 --
116~16
Contact rings 12 are spac0d a certain distance ap~rt
on the surface of the capacitor splice 7 o~ the lead-out 5,
each ring 12 being linked with its sheath 6 of the lead-
-out 5 having a specific electric potential.
~ he c~pacitor splice 4 o~ the termination 3 o~ the
cable joining the generator to external apparatuses is
provided with plates 11 connected to the contact rings 12
arranged on the surface of the capacitor splice 4.
Each contact ring 12 located on -the capacitor splice
7 of the lead-out 5 of the generator high-vol-tage winding
in a plane running parallel to a plane extending through
beginning of said capacitor splice 7 c~nd at a specific
distance between said planes is linked by means of a jum-
per 13 to the contact ring 12 located on the capacitor
splice 4 of the termination 3 in a plane running parallel
to a plane extending through the beginning of the capaci-
tor splice 4 of the cable termination 3 and at the same
distance between latter planes.
_Qp~ings in the casing 1 for letting through the cab-
le termination and the lead-out of the generator high-vol-
tage winding are sealed by gaskets 14.
In cable terminations operating conditions of insula-
tion are extreme since the electric field produced at the
edges of the termination is highly irregular and ruptures
are a frequent occurance. In order to improve conditions
of the insulation the termination is fanned out or spliced.
~o ob~ain ~avourable voltage distribution along the surfa-
- 6 -
116S~16
ce of the splice, the latter should be large enough. ~he
distribution of voltage along the surface of the capacitor
splice is affected by the capacitances between the plate
system of the splice, the current carrying elements of the
cable termination and grounded elements of the coupling
unit for connection of the ge~erator high-voltage winding
lead-out and the cable. Voltage throughout the sur~ace of
the capacitor splice can be compensated b~ making the spli-
ce larger.
~ hus, for example, with the line voltage of 220 kV in
the cable the capacitor splice is about two meters long.
~his entails a signi~icant increase of the overall dimensi-
ons of the coupling unit of the generator high-voltage
windi~g lead-out.
~ he jumpers 13 provided in -the proposed coupling unit
for connection of ~ generator high-voltage winding lead-o~t
and a cable permit setting of specific voltage on the pla-
tes 11 of the capacitor splice of the termination 3 and,
consequently, eliminating the effect of the capacitances
between the system of plates 11 of the capacitor splice 4,
the current carrying elements 8 of the cable term;nAtion 3
and grounded elements o~ the coupling unit for connection
o~ a generator high-voltage windin$ lead-out and a cable
and~ moreover, arranging adjioning plates 11 at a minimum
distance dictated by the electrical endurance o~ inaula-
tion with the given voltage drop between said plates 11.
~he voltage drop for any pair o~ adjoi~ing plates 11 is
-- 7 ~
1165416
a constant quantity defi~ed by the potential difference
of the neighbouring sheaths 6 of -the generator high-voltage
winding lead-out 5. ~ince the generator high-voltage winding
is in fact a multilayer cable and each shea-th 6 of the
generator high-voltage winding lead-out is linked to its
current carrying layer of the cable, the potential diffe-
rence of the sheaths 6 is kep-t constant.
The herein described coupling unit for connection of
a genera-tor high-voltage winding lead-out and a cable pro-
vides an opportunity to connect the generator high-voltage
winding lead-out to several cable terminations joining the
generator to various power consumers with var~ing angles
between the geome~trical axis of the generator winding lead-
~-out and the geometrical axes o~ the cable terminations.
~ he proposed invention permits a substantial reducti-
on of the dimensions and an increase of reliability of the
coup~ing unit for connection of a generator high-voltage
winding lead-out and a cable, as well as o~ the generator
as a whole.
-- 8 --
