RU2249893C1 - Ice and conductor vibration limiter for overhead power transmission lines - Google Patents

Abstract

FIELD: power engineering; limiting conductor vibration and galloping, as well as ice formation on overhead power transmission lines.

SUBSTANCE: proposed device is made in the form of flexible damping member (steel wire) with weights secured at its ends and clamp attaching this device to conductor and to center of steel wire. Weights are made of bent rods having short and long straight sections and bent section; thermosetting bushing is fitted onto one straight long section and end of the latter can be bent toward steel wire. Adequate make-up and optimal choice of size of rods provides for suppressing both low- and high-frequency vibrations of line conductors and for limiting ice formation on them.

EFFECT: reduced cost of power transmission line design, erection, and servicing.

3 cl, 3 dwg

Description

The invention relates to the field of electric power, and more particularly to limiters of icing and vibrations of wires of overhead power lines.

Wires and lightning protection cables of overhead power lines are subject to the simultaneous effects of various types of static and dynamic loads. The static action of the loads corresponds to the state of the wire and other parts of the structures or nodes of the lines when they do not experience acceleration and additional dynamic stresses do not arise in them. In the presence of accelerations, oscillations arise, which in some cases can give rise to resonance phenomena associated with a sharp increase in stresses. Therefore, the vibrations of the wires pose the greatest danger to the elements of the lines and can in some cases become the main factor determining their reliability. The destruction of the wires from vibrations is due to material fatigue and occurs at loads significantly lower than the design loads created by ice deposition or wind. However, if the danger of exposure to dynamic loads mainly depends on the duration of the oscillations, and static loads on the amount of ice deposition (uniform wind), then their combined action significantly increases the stress state of the wires and further worsens the situation with their bearing capacity and reliability.

Recent theoretical and experimental studies have shown that complex technical solutions are required that provide simultaneous restriction of vibration and dancing of wires, as well as the deposition of oversized ice, which would significantly increase the reliability of overhead power lines and reduce the cost of their installation and operation by two three orders.

Known vibration damper for the wires of an overhead power line, comprising an elastic damper element made in the form of a steel wire rope, cast weights rigidly fixed at a distance from the damper suspension at the ends of the damper element and a clamp made in the form of a grip and a die, the clamp being fixed on the middle part elastic damper element, and the grip is mounted on the wire using a die and a fixing bolt [1].

Such a damper is quite effective in damping aeolian vibrations in the frequency range from 5 to 100 Hz, where it has all the necessary natural frequencies, although in order to cover this entire frequency range for many linear objects, it is necessary to vary the length of the elastic damper element and the mass of the load distribution over length, which leads to an increase in the output range of absorbers used on overhead power lines of various voltage classes.

But the main drawback of this vibration damper is that it cannot work effectively both the ice limiter and the dance damper. To limit the amount of ice, it is necessary for the wire to increase the torsional rigidity that can be achieved by installing a load under the wire on a sufficiently long console. The resulting reactive torque from such a load will prevent the wire from twisting when ice is deposited on it. This will cause the formation of ice of elongated shape, more lightweight, instead of cylindrical, heavier (2-3 times).

The suppression of low-frequency vibrations (dancing) can be accomplished due to the disorder of torsional vibrations that control this process. The most acceptable devices for these purposes are pendulum dampers of dance on an elongated console, which conveniently fit into the vibration damper device due to the development of its geometric dimensions in the vertical plane.

The closest technical solution in relation to the proposed one is a limiter of icing and vibrations of the wires of overhead power lines, containing an elastic damper element, different masses of cargo made in the form of curved rods rigidly fixed at the ends of the elastic damper element, and a clip designed for suspension on the wire fixed at one end in the middle of the elastic damper element, and the other connected to the line wire [2].

However, this device has significant disadvantages:

- the constructive layout of the loads of this damper does not allow reaching their optimum sizes in order to ensure effective damping of vibrations, and even more so of low-frequency vibrations of large amplitude such as dancing wires;

- in addition, this absorber does not have enough leverage for the straight sections of the cargo rods (they are practically close to the elastic damper element) in order to develop the maximum torque that would stop the build-up of ice on the wire or at a positive temperature of the wire would lead to shedding ;

- in fact, the real damper is an inertial damper operating on the principle of Stockbridge dampers and, therefore, unable to suppress low-frequency vibration (2-4 Hz), which often occurs when frost or crystalline hoarfrost is formed on the wires, or dance when ice forms.

The authors set themselves the task of developing an integrated device that simultaneously dampens vibration, wire dancing and limits the amount of icing to sizes not exceeding the calculated values; currently widely used protective equipment against weathering is based on an individual approach to protection against each type of weathering. The task set by the authors is achieved due to the combination of essential features of the proposed technical solution, namely: a glacier and vibration limiter for overhead power transmission lines containing an elastic damper element, loads made in the form of curved rods rigidly fixed at the ends of an elastic damper element, and a clamp designed for suspension on a wire, fixed at one end in the middle of the elastic damper element, and the other connected to the line wire; moreover, the straight sections of curved rods located under the elastic damper element are made of such a length that their end sections extend beyond each other so that both weights and the elastic damper element form a closed oval contour operating as a single weight mass, with the total length L horizontal spacing of the rods from each other, measured between the points of their maximum bend, is in the range from 500 to 700 mm, the vertical distance D between the aforementioned straight sections is bent x is selected within the rods 30-45% with respect to L, and the gap l in the horizontal transverse plane elastic damping element between which call one after the other ends of the rods, by which their collision occurs during vibration, is 2-5% of L; one of the ends of the straight sections of curved rods has a curved bend towards the elastic damper element; a polymer shrink sleeve is fixed at one of the end sections of the segments of curved rods.

The invention is illustrated by drawings, where figure 1 is a General view of the limiter icing and vibrations of the wires of overhead power lines made in accordance with the present invention, a front view perpendicular to the wire; figure 2 is the same side view (along the wire) along arrow A in figure 1; figure 3 is a variant of the proposed device, made according to claim 2 of the claims.

The inventive limiter of icing and vibrations of the wires 1 of the overhead power lines consists of an elastic damper element 2, for example, a steel wire rope, weights 3, clamp 4, clamp 5 of clamp 4, die 6 of clamp 4 and mounting bolt 7. With clamp 4, the limiter is attached to the middle of cable 2 and with the help of a die 6, a gripper 5, it is suspended from the wire 1 of the overhead power line and fastened to it by means of a fixing bolt 7. At the ends 8, 9 of the cable 2 are rigidly fixed, for example, by crimping or in some other way ties 3. Loads 3 are curved rods having two straight segments (short 10 and long 11) and a curved segment 12; with a short straight section 10, the loads 3 are attached to the cable 2, and the long straight sections 11 of the rods 4 extend along each other along their length and are separated by a certain distance (gap) from each other on the horizontal length of the horizontal plane. This allows the rods 3 to collide with each other in the process arising on the oscillation line of the wires 1; and in order to eliminate noise and radio interference arising from the collision of the rods 3, a polymer heat-shrink sleeve 13 is put on one of the long straight sections 11 of the rods 3. The end of one of the straight sections 11 of the rods 3 can be bent (bend 14, see, for example, FIG. .3) with a certain radius of curvature in the direction of the cable 2. As a result of such an accepted design of the limiter for vibrations of wires 1, the elastic damper element and the load rods 3 form a contour closed in the vertical plane, which is, as it were, a unit ny massive unit, operating on the principle of eccentric load absorbers in dance.

To achieve the optimality of the damping properties of the limiter, the linear dimensions of its elements are calculated and selected in certain ratios and proportions. In particular, the total length L of the oval contour, measured between the points 15 of the maximum inflection of the rods 3, is assumed to be equal to from a minimum value of 500 mm to a maximum value of 700 mm; the bending radius of the rods 3 is taken large enough so that the vertical distance D from the short straight segment 10 of the rods 3 to the long rectilinear segment 11 of the rods 3 with respect to the selected value of L is in the range of 30-45% or in the absolute ratio is from 150 to 300 mm; at the same time, the distance (gap) l between the ends of the long straight sections 11 of the rods 3, which go one after the other, along the horizontal plane transverse to the elastic damper element 2, along which they collide during vibrations, is 2-5% of L or in absolute values - 10-30 mm.

The proposed limiter of icing and vibration of the wires 1 overhead power lines works as follows.

On the overhead power transmission lines, two forms of wire vibrations occur due to the action of wind and ice - high-frequency (tens of Hz), but small amplitudes of the order of the diameter of the wire and low-frequency (up to 2 Hz) sufficiently large amplitudes (dance). For effective vibration damping by any device, it is necessary that its damping system have the same or close natural vibration frequency. The indicated principle of damping the oscillations is achieved in the proposed limiter due to the special configuration of the load rods 3, which ensures the operation of the device both in the low-frequency and high-frequency ranges of oscillations and allows to increase the dissipation energy and the attenuation decrement of the system: elastic damper element 2 - loads 3. At the same time due to the significant spacing in the vertical plane of straight segments 10 and 11 of the rods 3 in the claimed limiter can significantly increase the length of the lever from the suspension and to long straight sections 11 and thereby increase the system torque, fixing torsional vibrations and acting also opposite to the torque, providing one-sided growth of ice on the wire 1. As a result, the damping is carried out at all frequencies of interest to us, covering as resonant forms of torsional vibrations of the wire and the resonant forms of bending vibrations of the elastic damper element 2. Changing the lengths of the straight sections 11 of the rods 3, as well as their weight (for example, lnym curved end of the segment) can cover the entire range of frequency fluctuations occurring on overhead power lines (vibration to dancing).

The proposed limiter of icing and vibrations of overhead power lines is a new type of damping device that solves the problem of reducing vibrations in a comprehensive manner, that is, it allows you to simultaneously dampen vibration, dance the wires and limit the amount of icing to a minimum size. This technical solution is effective in combating the dancing of wires and in damping high-frequency vibrational vibrations, which can significantly reduce the cost of designing, constructing and operating overhead power lines. Currently, the proposed device has been successfully tested at the test bench "ORGRES" and recommended for manufacture; serial production of such ice-forming limiters and vibrations of wires of overhead power transmission lines is expected.

Sources of information

[1] US Patent No. 4,159,393, class 174 - 42 (H 02 G 7/14), 06/26/1979.

[2] US Patent No. 3,400,209, class 174 - 42 (H 02 G 7/14), 09/03/1968.

Claims (3)

1. Limiter of icing and vibrations of the wires of overhead power lines, containing an elastic damper element, loads made in the form of curved rods rigidly fixed at the ends of the elastic damper element, and a clip designed for suspension on the wire, fixed at one end in the middle of the elastic damper element, and others connected to the wire line, characterized in that the straight sections of curved rods located under the elastic damper element are made of such a length that their The end sections extend one after another in such a way that both the load and the elastic damper element form a closed oval-shaped contour operating as a single weight mass, while the total horizontal separation distance L of the rods from each other, measured between the points of their maximum bend, is ranges from 500 to 700 mm, the vertical distance D between the aforementioned rectilinear segments of curved rods is selected within 30 ÷ 45% with respect to L, and the gap l in the horizontal transverse elastic damper element is plane the ty between the ends of the rods that come one after another, along which they collide during oscillations, is 2–5% of L. 2. The limiter according to claim 1, characterized in that one of the ends of the straight sections of the curved rods has a curved bend towards the elastic damper element. 3. The limiter according to claim 1, characterized in that at one of the end sections of the segments of the curved rods is fixed polymer shrink sleeve.

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