Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Field o the Invention
The invention relates to electric power transmission
lines, and more particularly to a device ~or telemetering
the effect of loads on the line conductors.
The invention is used for monitoring the loads created
on overhead line conductors by accumulated ice and may also serve
formeasuringother line conductor loads, such as wind pressure
and the dynamic stresses due to the conductors swinging with a
considerable amplitude.
Background of the Invention
Known in the art is a device for telemetering loads on
power transmission line conductors tcf. "Energetika za Rubezhom",
Telemetering of Ice Loading of Power Transmission Line Conductors,
BTI ORGRES, Moscow, 1967, p.3-14, Fig. 1) comprising load sensors
arranged along power transmission lines located in regions where ice
and sleet is a problem. Each load sensor is attached to the point
of suspension of the line conductor to the supporting structure
and is coupled electrically to a transducer converting the load
sensor output signal into a high-frequency signal supplied via
a communication channel to the high-frequency signal receiver
installed at the nearest substation or at the control station.
The device also has ice load sensors mounted on the power
transmission line and coupled electrically to a tranaucer con-
verting the sensor output signal into an electric signal.
The above-mentioned device for telemetering the loads on
power transmission line conductors measures the resultant con-
ductor load including the weight o~ the conductor and accumulated
ice, wind pressure and the dynamic stresses caused by the conductor
swing. The wind pressure may alter the resultant conductor load
by several hundreds of kilograms. The most important component
of the resultant conductor load is the ice loading that can be
eliminated effectively by melting the ice.
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The data on the degree of conductor loading is trans-
mitted by radio from the line supporting structure carrying the
load sensor to the substation or control station receiver.
The ice load sensor and the radio communication antenna
are mounted on a wooden pole and transmit the ice load signal
before the ice accumulates on the line conductors.
The ice load sensor comprises a spherically wound piece
of wire suspended so that the weight of 60 to 90 grams of ice
accumulated on the wire causes the operation of a microswitch
which switches o~er the signal transmission line from the load
sensor.
llhus, the information on the ice loading of the line
conductor contains data on the conductor load and the appearance
of ice. However, the installation of the ice load sensor beyond
the line conductor does not allow obtaining reliable information
on the actual degree of ice loading of the power transmission
line conductors.
The device employing a spherical ice load sensor also
has other disadvantages. The data provided by the device has
to be analyzed each year to establish the correlation between
the rate of ice accumulation indicated by the ice load sensor
and the subse~uent accumulation of ice on the line conductors.
Moreover, the ice load sensor is subject to frequent mechanical
failures and has a tendency to freeze.
Another disadvantage of the known device is that it does
not provide reliable information on the ice loading of a line
conductor, which makes it impossible to make a proper decision
as to the necessity and efficiency of melting the accumulated ice.
Summary of the Invention
It is an object of the present invention to provide a
highly efficient device for telemetering loads on power transmis-
sion line conductors.
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Another object of the present invention i8 to simplify
the design features of the device.
These objects are accomplished by that in a device for
telemetering loads on power transmission line conductors, com-
prising load sensors arranged along transmission lines in ice and
sleet hazardous locations and attached at the points of suspen-
sion of the line conductors to the supporting structures, said
sensors being coupled electrically to a respective transducer
converting the load sensor output signal into a high-frequency
signal delivered to a high-frequency signal receiver, and ice
load sensors mounted on the power transmission line and coupled
electrically to a respective transducer converting the ice
load sensor output signal into a high-frequency signal, in accor-
dance with the invention, each ice load sensor is provided with
a source of radioactive radiation, secured directly on one of
the line conductors, and a radioactive radiation detector mounted
on the same line conductor on the path of the radiation and coupled
electrically to the transducer converting the load sensor out-
put signal into a high-frequency signal.
Such an embodiment of the hereinproposed device for
télemetering loads on power transmission line conductors makes
it possible to establish the nature of the resultant load and
determine the magnitude of the ice load component, thus allowing
the ice to be efficiently melted without undue losses.
Brief Description of Accompanying Drawings
The invention will be further described by way of example
with reference to the accompanying drawings, wherein:
Fig. 1 is a schematic representation of a device for
telemetering loads of power transmission lines conductors in
accordance with the present invention;
Fig. 2 is an isometric representation of the device for
telemetering loads of power transmission line conductors in accor-
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dance with the present invention.
Detailed Description of the Invention
The hereinproposed device for telemetering loads on
power transmission line conductors comprises load sensors 1
(Fig. 1~ installed along a power transmission line passing through
a region affected by ice accumulation on line conductors. Such
areas are determined from the results of meteorological surveys.
Each load sensor 1 is fixed in place at the point of suspension
of a line conductor 2 to a supporting structure 3 between insu-
lators 4 and the line conductor a. The load sensors 1 may beof any known type employed for the purpose.
In the vicinity of the load sensor 1, the same line con-
ductor 2 carries a transducer 5 converting the load sensor out-
put signal into a high-frequency signal. The transducer has two
inputs 6 and 7. The load sensor 1 is coupled electrically to
the transducer 5, its output being connected to the input 6 of
the transducer 5.
The device has an ice load sensor 8 also attached to
the line conductor 2 having its output connected to the input 7 o
the transducer 5. The transducer 5 serves for converting the
signals delivered from the load sensor 1 and the ice load sensor
8 into a high-frequency signal and supplying it to a telemetering
signal receiver 9. The signals of the load sensors 1 and 8 àre
supplied successively by a time switch (not shown) of the trans-
ducer that converts the load sensor signals into high-frequency
signals. An inductive source of supply may be used or the de-
vice (cf. "Energetika za Rubezhom", Telemetering of Ice Loading
of Power Transmission Line Conductors, BTI ORGRES, Moscow, 1967,
p. 11, Fig. 5) The ice load sensor 8 comprises a source 10 of
radioactive radiation mounted directly on the line conductor and
a radiation detector 11 fitted on the same line conductor on
the path of the radiation.
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Since the ice layer 12 is usually of unequal thickness
around the perimeter o~ the line conducto~ 2, it is of adv~ntage
to employ an annular ice load sensor 8 (Fig. 2).
The source 10 of radioactive radiation is in the form
of a cylindrical container mounted coaxially on the line con-
ductor 2. The end of the container, facing the detector 11, has
radiation emitting openings even~ly distributed along the circum-
ference of the end face. The diameter of the circumference is
1 to 2 mm greater than that of the line conductor 2.
The detector 11 of radioactive radiation is in the form
of a ring with stiffening ribs mounted coaxially on the line con-
ductor 2. The end of the detector 11, facing the source of
radiation 10, has radiation sensitive elements evenly spaced along
a circumference 2 to 20 mm greater ln diameter than the permis-
sible thickness of the ice accumulated on the line conductors.
The permissible thickness of the ice layer is determined according
to the mechanical strength of the line conductors.
The openings emitting the radioactive radiation are made
so that the radiation is incident upon the sensitive elements of
the detector 11.
The hereinproposed device for telemetering loads on
power transmission line conductors operates in the following man-
ner.
When ice accumulates or wind blows on the line conductor
2 (see Fig. 1), the load sensor 1 producès a signal in proportion
to the resultant load. The load sensor output signal is supplied
to the input 6 of the transducer 5 that converts it into a high-
frequency signal. The radioactive radiation emmited by the source
10 passes through the layer of ice 12, is partially absorbed by
the layer, and the remaining part of the radiation is registered
by the detector 11, becomes an electric pulse delivered to the
transducer 5 converting it into an electric signal.
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The transducer 5 supplies the communication ch-lnnel
with a high~frequency carrier periodically time-modulated so
as to deliver the ice load signal of the sensor 8 and the load
signal of the sensor 1 separately. The ice load carrier signal
of the sensor 8 has, for instance, a 3-sec duration and the load
carrier signal of sensor has a 4-sec duration. The interval
between the two siynals may be, for instance, of 10-sec duration.
The difference in time of delivery of the high-frequency carrier
signal makes it possible to distinguish between the information
obtained from the signals of the sensors 1 and 8.
The radio communication channel or high-voltage phase-
ground conductor of the power transmission line may serve as
the communication channel delivering the high-frequency signal
to the receiver 9.
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