RU209764U1 - Adaptive magnetorheological damper of dance and vibration of wires of overhead power lines - Google Patents

Abstract

The utility model relates to the field of electric power industry, in particular to designs of dance and vibration dampers for wires of overhead power lines, made using magnetorheological fluids capable of changing their rheological properties under the influence of an external magnetic field. The damper is attached to the garland of insulators through the fasteners by means of eyelet 3 in the upper cover-flange 1, and the wire clamp is attached to the lower end of the rod 19. The rod is connected to the piston 7, dividing the volume of the cylindrical body 6 into the working 9 and compensation chambers, hydraulically connected by an annular channel 33 inside the piston. Vibration damping of the wires is carried out by the forces of viscous friction of the fluid in the channel 33, the elastic force of the spring 12 between the piston and the cage 13 of the stuffing box 14 and the gas pressure force 11 between the membrane 10 and the top cover of the damper 1. To control the damping of the vibrations of the wires in the piston 7 there is a coil 32 with a magnetic circuit 22, 23, which changes the rheological properties of the magnetorheological fluid in the channel 33, and, consequently, the resistance force. The adaptive control of the dance is carried out by a control system located in the electronics unit 41 at the bottom of the piston. 3 w.p. f-ly, 2 ill.

Description

Technical field

The utility model relates to the field of electric power industry, in particular to designs of controlled dance and vibration dampers of overhead power transmission lines, made using magnetorheological fluids capable of changing their rheological properties under the influence of an external magnetic field.

Wind and ice formations exert static and dynamic force effects on overhead power lines (TL), leading to wear and destruction of high-voltage fittings, wire breaks, whipping of conductors with ground wires and with each other, and destruction of insulator strings. The most vulnerable nodes of overhead power transmission lines are insulator garlands, which directly perceive the force effects exerted by wires oscillating due to wind gusts. At the same time, ice formations exacerbate oscillatory processes in overhead lines, increasing the area of the wire profile that perceives the wind load, which is why the largest number of accidents on power lines occurs precisely in the autumn-winter period [1, 2]. Moreover, the fall of the ice causes the wire to jump and twist, thereby exerting a shock load on the mounting fittings of the power transmission tower.

Vibration of power transmission line wires with a frequency of 10-100 Hz occurs at wind speeds of 0.6-0.8 m/s. Vibration results in breaks in the wires of wires, self-loosening of fastening bolts, wear of parts of the fittings of insulator strings. Operating experience shows that vibration of wires is observed most often on lines passing through open and flat terrain. Especially dangerous is the vibration of power lines at river and water crossings with spans of more than 500 m.

The dance of wires refers to low-frequency oscillations of the order of 0.2 - 5 Hz with an amplitude of 10-100% of the sagging arrow of the power line wire and is due to the interaction of its vertical and torsional vibrations. As a rule, the dance of wires is observed on overhead lines with a voltage of over 110 kV. The danger of dancing lies in the fact that the oscillations of the wires of individual phases, as well as wires and cables, occur out of sync: often there are cases when the wires move in opposite directions, approach or overlap. In this case, electrical discharges occur, causing melting of individual wires, and sometimes wire breaks.

To protect fittings and wires from dancing, overlaps and aeolian (high-frequency) vibration, various types of vibration dampers are used on power lines. Phase, interphase spacers and pendulum dampers are used to limit the dance of wires and prevent their overlap. Spring dampers, Stockbridge dampers and dampers with spring-loaded weights, operating on the principle of dynamic dampers, are actively used to dampen aeolian vibration on overhead transmission lines of any voltage [3].

State of the art

Known damper dancing and vibration wires overhead power lines, consisting of a clamp, a spherical body filled with a viscous liquid, with a spring-loaded mass inside [4]. Vibration damping is provided by the work of gravity, inertia, elasticity, viscous damping and dry friction. The main disadvantage of such a damper is the narrow operating frequency range and low efficiency in the region of low-frequency oscillations. Compensation for this disadvantage is possible by using a damper with a larger mass, which, in turn, will lead to a decrease in the effectiveness of the fight against high-frequency vibration.

Known tension clamp to dampen the dance and vibration of the wires of overhead lines, consisting of a piston connected to the housing by means of Belleville springs [5]. The clamp protects the strings of insulators by directly absorbing axial loads acting when the wire vibrates. The reduction of loads on insulators is carried out mainly due to the work of elastic forces. The disadvantage of the technical solution is the almost complete lack of protection against dancing and overlapping wires on each other. In addition, these clamps are only suitable for installation on power line anchors.

Known damper dancing wires overhead lines with a split phase, consisting of a double-arched carrier frame, double-arm pendulum, phase strut and damper torsional vibrations [6]. The damping of the dance of wires is carried out due to the work of the forces of inertia, gravity and dry friction. The main disadvantages of the technical solution are the bulkiness and massiveness of the structure. In addition, such an absorber is ineffective in damping high-frequency vibration, can only be installed on a line with a split phase, and may partially lose its functions in the event of icing.

Known vibration damper for wires of overhead power lines, which includes a sealed housing with a clamp filled with magnetorheological fluid, a piston disk with a pendulum and electromagnets [7]. The damping of the dance and vibrations of the wires is carried out by using the forces of inertia, gravity and viscous friction. The main disadvantage of this design should be considered the hinged connection of the pendulum with the piston disk, which can lead to unpredictable behavior of the damping system and the impossibility of effective control of the fluid viscosity. Moreover, the design description does not disclose the location of electromagnets and supply leads, the direction of magnetic field lines.

A device for damping oscillations of overhead line wires is known, consisting of a cylindrical body and a rod with loops for hanging wires, two contiguous springs with opposite winding [8]. Thus, vibration damping will be carried out due to the forces of elasticity and dry friction between the springs, the rod and the housing. In addition, such a damper provides increased protection of insulator strings from shock and accidental force effects. The disadvantage of the design is the low damping capacity, the possibility of amplifying the oscillations of the wires due to resonance. Moreover, in the event of multiple jamming of the coils of the springs, the damper may lose its function.

The closest to the proposed utility model in terms of technical essence is the controlled dance damper of wires of overhead power lines, described in the patent [9]. The device consists of a housing, a piston rod with a permanent magnet, a spring, an electromagnetic coil, an accumulator, a transducer, an accelerometer and a heating element. The energy generated by electromagnetic induction is used to melt ice formations on the device, as well as to send a signal from the accelerometer to monitoring devices. Vibration damping is carried out due to the force of elasticity.

The proposed device has a number of disadvantages. Firstly, the device is of little use for damping the horizontal components of oscillations, and uses only the elastic force for vibration damping, which in turn can contribute to the resonant amplification of the vibrations of the wires. Secondly, many sensors and electronic components of the device can be affected by a magnetic field from the side of the wire, which can lead to incorrect operation. Thirdly, many design elements increase the complexity and cost of the device without increasing its efficiency, such as the accelerometer, monitoring station, insulating layer and control system.

The essence of the utility model

The objective of this utility model is to reduce the intensity and amplitude of the dance and vibration of the wires of overhead power lines, as well as to prevent the destruction of fasteners, insulators and breakage of the wires of the end and anchor supports due to the action of variable and random wind and ice loads. The technical result is achieved by means of an adaptive magnetorheological damper installed between the string of insulators and the wire, which has the following set of essential design features:

the adaptive magnetorheological damper includes a piston rod capable of moving inside a housing filled with a magnetorheological fluid, thereby creating a resistance force during movement;

between the bottom cover and the damper piston there is a compression spring;

the piston contains an electromagnet in its composition, which makes it possible to control, by inducing an external magnetic field, the viscosity and yield strength of the magnetorheological fluid in a narrow annular channel inside the piston, thereby changing the force of resistance to its movement;

uninterrupted supply of the electromagnet is ensured by the presence of a battery inside the piston and a primary power source installed on the protected wire, and these elements are electrically connected by current-carrying leads passing through a hole inside the rod;

the piston contains an electronics unit, including a battery, an accelerometer, a transducer and a control system designed for adaptive control of the resistance force.

Brief description of the drawings

The possibility of implementing the utility model is illustrated by the drawings. In FIG. 1 shows a general view of an adaptive magnetorheological dance and vibration damper for wires of overhead power lines; in fig. 2 is a general view of the magnetorheological piston of the dance and vibration damper of the wires of overhead power lines.

The adaptive magnetorheological damper consists of a top cover-flange 1 with a number of concentric holes, a nipple 2 for gas injection and an eyelet 3 for connection with mounting fittings, at least four long tightening bolts 4, a sealing ring 5, a hollow cylindrical steel body 6, inside which the piston 7 is located, dividing the body into hydraulically interconnected compensation 8 and working 9 chambers, elastic corrugated membrane 10 separating the gas accumulator 11, compression springs 12, stuffing box holder 13, stuffing box with a sealing ring 14, bottom cover-flange of the damper 15 with concentric holes of at least four bolts 16, four washers 17 and nuts 18, a rod 19 with a hole for electrical outlets 20 and an eye 21 for attaching wires to fittings.

The magnetorheological piston 7 consists of an upper steel cover of a hollow cylindrical shape with a number of concentric arcuate holes and a number of round holes 22, a steel base 23 with an L-shaped hole 24 and concentric round holes with a machined internal thread, at least three connecting screws 25, non-magnetic an annular cover 26, sealing rings 27, 28, 29, a cylindrical compartment 30 with an internal hole (not shown in the drawing, located opposite the hole 24), an electromagnetic coil 31 with a copper winding 32 and leads coming out of the inside (not shown in the drawing), an annular hydraulic channel 33 filled with a magnetorheological fluid, at least one piston ring 34, a lower steel piston cover 35 with concentric long arcuate holes, round through holes 36 and holes with machined threads for screws 37, a centering ledge 38 and a cylindrical hole 39, cylindrical plastic box 40, electronic component box 41, and at least four connecting screws 37.

Information confirming the possibility of implementing the utility model

The adaptive magnetorheological damper consists of a steel cylindrical hollow body 6, inside of which there is a movable piston 7 with a steel rod 19 rigidly fixed on it. 33 in piston 7.

From below, the working chamber 9 is limited by the cage 13 of the stuffing box 14, which is rigidly fixed on the body of the damper 6 by means of a bolted connection 16. stuffing box.

Between the piston 7 and the stuffing box 13 in the working chamber 9 there is a steel spring 12, which works mainly in compression. The upper end of the spring 12 is fixed on the centering protrusion 38 at the bottom of the piston 7. The lower end of the spring 12 fits snugly against the holder 13 due to the pressure force, and during operation it is also pressed by the weight of the wire. In order to prevent misalignment of the spring 12 during operation, its lower end is centered by the presence of a protrusion on the clip 13.

The compensation hydraulic chamber 8 of the damper is limited from above by an elastic membrane 10, on the other side of which there is a gas accumulator 11. Inside the gas accumulator 11, limited by the membrane 10 and the top cover of the damper 1, gas is contained at a pressure of 3-10 bar. Gas is pumped into chamber 11 through nipple 2 in the top cover of damper 1.

Fixation of the upper cover-flange 1 on the body is carried out by its connection with the bottom cover-flange 15 by means of long bolts 4, nuts 18 and washers 17. connection "protrusion - depression". The tightness of the compensation chamber 8 and the gas accumulator 11 is ensured by the sealing ring 5 located between the top cover 1 and the body 6. The membrane 10 is also clamped between the body 6 and the cover 1 due to the presence of thickenings along the edges and a concentric groove on the upper base of the body 6, which prevents the possibility of a breakdown membrane 10 during operation.

The piston 7 consists of an upper steel magnetic cap 22 and a steel magnetic core 23 connected to each other by screws 25. In this case, a coil 31 with a copper winding 32 is put on the core, placed in a cylindrical housing 30 made of non-magnetic material (stainless steel, duralumin). The housing 30 is necessary to prevent the ingress of the working fluid from the channel 33 into the winding 32, for which it is covered with an annular cover 26 made of PTFE or other solid material with low friction. When tightening the screws 25, the cover 26 squeezes the sealing rubber rings 27, 28 located on the walls of the cylindrical body 30 and providing good tightness of the piston 7 structure.

The current-carrying leads of the copper winding 32 exit through a hole in the lower part of the coil body 31, a corresponding narrow hole in the cylindrical body 30, an L-shaped channel 24 in the core 23 and are connected to a power source inside the electronics unit 41 in the lower part of the piston.

The electronics unit 41 is a cylindrical box 40 made of a dielectric material (getinaks, textolite) with an accelerometer, a battery, a converter and a microcircuit with a control algorithm embedded inside it. The box 40 is located inside the “glass”, which is the lower part of the steel core 23, and is tightly pressed from below by the piston cover 35. To increase the tightness of the connection between the steel bottom cover 35 and the box 40, a rubber sealing plate 29 is located. The bottom cover 35 is put on the protrusions of the “glass” core 23 through the hydraulic concentric holes and rests against them. In this case, the load falling on the dielectric box 40 when squeezing the plate 29 will depend on the size of the gap between the box 40 and the cover 35, as well as the rigidity and thickness of the plate 29.

After installing the bottom cover of the piston 35 on the protrusions of the "glass" of the core 23, the parts are connected by screws 37, for which purpose side concentric holes 36 are provided in the cover 35. In this case, the shells of the top 22 and bottom covers 35 abut against each other, connecting according to the "protrusion - depression" principle ". A piston ring 34 is also put on the outer surface of the top cover 22 to center the piston 7 relative to the housing 6, to prevent the flow of working fluid between them, to reduce friction and abrasion of surfaces.

On the bottom cover of the piston 35 there is a cylindrical protrusion for mounting the compression spring 12. Inside the bottom cover 35 there is a through hole 39 associated with a long channel inside the stem 20, along which the wires run connecting the electronics unit 41 with the primary power source installed on the protected wire. The rod 19 is connected to the lower piston cover in the region 42 by means of a threaded connection, or is one solid body with it.

An annular hydraulic channel 33 is formed between the top 22 and bottom 35 piston covers, the core 23 and the cylindrical body 30, as well as the annular cover 26 and the sealing ring 28. concentric holes, which are a continuation of the channel 33.

The principle of operation of the utility model

The damper body is attached to the string of insulators through the fasteners by means of eyelet 3 in the upper cover-flange 1. The outer end of the rod 19 is attached by eyelet 21 to the supporting or tension clamp of a single wire or a clamp for wires of a split phase of an overhead power line. Accordingly, the electrical potential of the damper will be equal to the potential of the wire.

When the adaptive magnetorheological damper is located between the garland of insulators and the protected wire inside the damper, under the action of an external variable force (for example, when the wire vibrates in a vertical plane), the spring-loaded rod 19 with the piston 7 moves, into which the electromagnetic coil 32 of the magnetorheological transformer is built. In addition to the coil 32, the transformer incorporates a magnetic circuit 22, 23 and an annular hydraulic channel 33, through which a magnetorheological fluid flows between the chambers 8, 9. As a result of the movement of the piston rod 7, for example, when lowering the held section of the wire during galloping, the volume of the working chamber 24 decreases. Due to the pressure difference, part of the magnetorheological fluid flows through the throttle channel 33 from the working chamber 9 into the compensation chamber 8. chamber 8, the pressure inside the latter is balanced by the pressure of compressed gas 11, which fills the space between the membrane 10 and the cover-flange 1. The presence of such a chamber makes it possible for the rod 19 to move inside the damper, protects it from axial shock loads, somewhat improves the quality of vibration damping in the low-frequency range and allows to prevent the dangerous phenomenon of cavitation that occurs when there is a large pressure difference between the chambers 8, 9 and leads to the destruction of the inner walls of the hydraulic devices.

The compression spring 12, coupled with the viscous friction force inside the moving piston 7, creates a resistance force in the vertical plane and, partially, in the horizontal plane. In this case, the spring 12 is calculated in such a way that its up and down stroke is approximately the same, taking into account the acting pressure force from the gas accumulator 11 and the weight of the wire brought to the rod 19. The possibility of rotation of the piston rod 7 inside the damper makes it possible to compensate for the insufficient hinge of the attachment garlands of insulators to the traverses, which leads to their destruction and wire breakage. Articulation is provided by two degrees of freedom, and structurally - by a compression spring 12 and rotation of the piston rod 7.

The magnetorheological piston functions as follows. With a periodic force effect on the hydraulic suspension, the working magnetorheological fluid will flow between the chambers along the hydraulic annular channel 33 formed between the steel covers 22, 35, the core 23 and the cylindrical compartment 30, as well as between the sealing elements 26, 28, 29, and through the arcuate holes in covers 22, 35, which is a continuation of the channel 33. In this case, the movement of the piston will be a resistance force, one part of which is proportional to the piston speed, and the other part is proportional to the yield strength of the hydraulic fluid. The outer walls of the piston 7 fit snugly against the inner walls of the hydraulic suspension, therefore, there is no fluid flow between them, and due to the presence of fluoroplastic piston rings 34, friction will be minimal. When the force action from the side of the oscillating wire causes the damper to stretch/compress with an acceleration above the threshold value, an electrical signal from the accelerometer appears at the input of the magnetorheological transformer control system, at the output of which the key control algorithm of the converter powered by the battery is formed. At the output of the converter located in block 41, a current up to I = 0.5 A will be generated, which will go to the winding of the coil 32 through the leads located in the channel 24. Thus, a magnetic field will arise inside the piston, the lines of force of which will close through the core 23 , top cover 22 and some area of the annular channel 33 with magnetorheological fluid. As is known, the yield strength of a magnetorheological fluid even in relatively weak magnetic fields (50-100 kA/m) can reach several tens of kPa, and under the action of transverse fields the magnetorheological effect is approximately 1.3-1.5 times stronger. Thus, the design of the piston provides a wide range of control over the yield strength of the magnetorheological fluid flowing through the hydraulic channel 33 due to its small width and the direction of the magnetic field transverse to the fluid flow.

Due to the unique properties of magnetorheological materials, the adaptive damper is able to adjust to the changing dynamic characteristics of the input vibration signal. This leads to a change in the damping coefficients and stiffness in the oscillatory system "wire-damper". The control magnetic field will change in phase with the change in the frequency of the external vibration signal. To achieve this goal, the control system adapts to changes in the linear weight of the wire (icy deposits) and the force of the wind. This leads to damping and detuning of vibrations of the protected wires.

Literature

1. Preparation for the autumn-winter period 2016-2017, the passage and main results of the 2015-2016 OZP / Ed. Deputy Minister of Energy of the Russian Federation A.V. Cherezov. 2016. - 216 p.

2. Ratushnyak V.S. Statistical analysis of emergency power outages due to icing on the wires of power transmission lines in the territory of the Russian Federation [Electronic resource] / V.S. Ratushnyak, V.S. Ratushnyak, E.S. Ilyin, O.Yu. Vakhrusheva // Young science of Siberia: electron. scientific magazine - 2018. - No. 1. - Access mode: http://mnv.irgups.ru/toma/11-2018, free. - Zagl. from the screen. - Yaz. Russian, English (date of access: 03/10/2021).

3. Brochure No 322 CIGRE “State of the art of conductor galloping”, 2007, Paris, 142 pp.

4. Vibration damper. Patent US 3780207A.

5. Galloping preventive device JP 2004036770 A.

6. An absorber for the dance of split wires, its torsional vibration damper, an overhead power line with such an absorber and an overhead power line with a dance absorber equipped with such a damper RU 2716701 C1.

7. Absorber of low-frequency oscillations of wires of overhead power lines (options) RU 2570347.

8. Device for vibration damping of wires RU 2621722.

9. Device for reducing power transmission line galloping and application method thereof. Patent CN 103594996 A.

Claims (4)

1. A damper for dancing and vibration of wires of overhead power lines, connected to a wire and a garland of insulators by means of mounting fittings and containing a steel cylindrical body, upper and lower covers and a piston rod dividing the volume of the damper into two chambers hydraulically connected through a narrow annular channel, filled with working liquid, and between the piston and the bottom cover of the damper there is a compression spring, the top cover and the rod contain lugs for fastening to the garland of insulators and the wire by means of fasteners, characterized in that the compression spring is rigidly fixed on the centering protrusion of the piston rod, and its free end rests into the cage of the sealing gland, which has a protrusion for fixing the spring and is rigidly fixed on the bottom cover of the cylindrical damper housing by means of a bolted connection together with the gland; under the top cover, the device contains an elastic membrane separating the hydraulic chamber and the gas accumulator, and a nipple is provided for pumping gas in the top cover of the damper; as a working medium, a magnetorheological fluid is used, which changes its rheological properties when exposed to external magnetic fields created by an electromagnet located inside the piston and powered by a control unit located at the bottom of the piston. 2. The damper according to claim 1, where the piston consists of a steel ferromagnetic cover mounted on a magnetic core by means of a screw connection, between which a coil with a copper winding is rigidly fixed, located inside a cylindrical closed case made of duralumin or stainless steel and sealed with a pair of sealing rings; between the lower core cup and the steel bottom cover of the piston, interconnected by screws, a cylindrical dielectric box with a control unit is tightly fixed by means of a sealing ring between the box and the bottom cover, and between the steel covers, the core and the sealed coil body, a hydraulic annular channel is formed, through which flows magnetorheological fluid, and the fluid flow through the covers is ensured by the presence in them of long arcuate holes connecting the annular channel with the hydraulic chambers; the electromagnet winding is connected to the electronics unit through leads inside the L-shaped channel in the magnetic core, in turn, the electronics unit is connected to the primary power source through leads in the channel inside the piston rod. 3. The damper according to claim 2, where the rod and the bottom cover of the piston are one body, and the lug is connected to the rod by means of a threaded, collet or other connection. 4. The damper according to claim 2, where the rod and the lower piston cover are two bodies connected in the area of the piston centering ledge by means of a threaded connection.

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