RU2616591C2 - Line filter for transmission systems on ac transmission lines of average/high voltage - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: for using in electric engineering. According to the invention a line filter for transmission systems on ac transmission lines of average/high voltage comprises a continuous coil of conductive metal, wherein the coil is formed by a continuous spiral made of coil turns (1, 1A, 1B, 1C) which are wound as a solenoid and held with laying sequence (2) separated from one another and made of electrically insulating material. Coil turns (1, 1A, 1B, 1C) have an H-shaped cross section, so that a groove or continuous channel which enclose layings (2) were formed on each of the opposing surfaces of coil turns. This layings (2) create a reliable base for each coil turn.

EFFECT: invention increases resistance to the line filter winding deformation.

4 cl, 2 dwg

Description

Technical field

The present invention relates to linear filters for transmission systems on medium / high voltage alternating current power lines.

State of the art

Line filters are well known and widely used to transmit (in a manner commonly referred to as PLC (power line communication)) waves traveling along medium / high voltage AC power lines, i.e. for transmitting signals, information, voice information and data along long line segments, while such segments are limited to linear filters connected in series with the line to form a high impedance for the frequencies of the transmission signal and a negligible impedance for the frequency of the electric current transmitted along such a medium line / high voltage. Such linear filters are subject to very high loads, since they must withstand large currents in the line (the voltage of which can be many tens or hundreds of kilovolts), and short-term short-circuit currents at the point at which such coils are installed. Obviously, such electric currents generate very intense magnetic fields that expose the linear filters to very high mechanical forces, especially at peak short-circuit currents.

As already mentioned, linear filters have a well-known structure: summarizing, we can say that they contain a continuous winding solenoid made of metal with high electrical conductivity (most often aluminum), with each coil being separated from its neighboring coil by gaskets of electrically insulating material - these gaskets should prevent mutual movement between metal coils. Line filters must comply with very strict IEC standards (the most stringent of which is IEC 357, published in November 1989).

Known coils consist of continuous spirals formed from coils of coils (usually aluminum) having a quadrangular (substantially square) cross section. Gaskets have a different shape and structure, for example, they are made of continuous glass fibers that cover the outer surface of each coil, then pass along the upper surface of the same coil, passing behind its inner upper edge, then bend around it, passing below the lower surface of the coil, and overlap on the previous turn, then they are bent so as to overlap the outer surface of this turn, and so on, passing on opposite surfaces and on the outer surfaces of all turns. Continuous glass fibers form thickenings at the points where they are bent over themselves, on the lateral edges of the coil turns and behind them.

Another type of insulating spacers consists of elements of insulating material (made, for example, fiberglass) of a substantially U- or H-shaped cross-section for defining nests in which sections of one or two opposite turns of the coil are placed, the surfaces of which are thus held spaced apart from each other.

The entire surface of the turns of the coil and gaskets is filled with cold-cured two-component epoxy resin to prevent voids - even very small ones - between the opposite surfaces of the gaskets and turns of the coil, in order to prevent even very small mutual movements between different spirals under the influence of electric current.

The above-described metal coils and gaskets have the disadvantage that they are not able to reliably prevent either sliding or mutual movement of one coil of the coil relative to its adjacent coil of the coil, or bending of the coil after passing through it a high voltage electric current.

Documents related to the prior art, namely, US3991394A, US2497516A and DE2241975A, describe linear filters for medium / high voltage AC power line transmission systems, but none of them describe filters formed by windings made of coil turns of an electrically conductive metal in which each coil is held in a reliable position relative to its neighboring coil in the winding of a continuous spiral coil, or solenoid, of which it is a part.

US3991394 shows an inductor for medium / high voltage power lines having seven layers (labeled 1-7) that are held together and attached to supports by fiber material and cement. Each of these seven layers contains four coils having rectangular conductors (see col. 3, p. 3-9).

The main objective of the present invention is the creation of linear filters having a very simple design, providing very high resistance to deformation, and minimizing the possibility of lateral displacement and bending of one coil of the coil relative to its neighboring turns under the action of an electric current passing through the turns of the winding and, in in particular, under the action of mechanical forces created by asymmetric peak values of short-term short-circuit currents.

Summary of the invention

This and other problems are solved using linear filters formed from coil turns of a metal with high electrical conductivity (preferably aluminum or copper), an essentially H-shaped cross section, the formation of a continuous channel or recess in each of the two opposite surfaces of each metal coil relative to adjacent to it, while in these cavities are located and held gaskets made continuous or in the form of consecutive contacting parts to form such a azom reliable coils each coil support with an adjacent coil turns of a continuous spiral metal coils forming the windings or coils of the linear filter.

As you know, linear filters are held by two rigid heads or end multi-beam supports. The ends of the electrical connecting plates or pins are attached to these metal multipath supports and protrude outward from the coil windings or solenoids at these ends for connection to high voltage lines.

Line filters are connected to the lines in series: two end multipath supports of each filter are firmly connected to each other by insulated rods of different types, for example, stainless steel rods, the two ends of which (passing through holes made in metal end multipath supports) are threaded and fixed on metal end multipath supports by means of ceramic or insulating polymer insulators inserted between them with nuts and locknuts. Stainless steel rods are also known that are inserted (and electrically shielded) into openings in polymer or glass insulators that provide electrical insulation between the two end multi-beam supports of each line filter. Such known solutions have disadvantages because they are expensive and do not allow metal coils and corresponding gaskets to strongly compress between the two end multi-beam supports of each linear filter.

Thus, another objective of the present invention is to provide rods of simple design and easy to install, which allow you to strongly compress the metal turns of the coil and gaskets between the end multi-beam supports of each linear filter.

This task is achieved using rods completely made of fiberglass rods impregnated with resin, at least two ends of which are threaded and fixed in the outer surfaces of each multipath support only with nuts and locknuts screwed onto the threaded ends of these rods protruding from the multipath supports through holes made in metal multipath supports. The distinguishing features of the linear filter of the present invention are defined in paragraphs. 1-4 of the attached claims.

Brief Description of the Drawings

For a clear understanding of the structure and features of the blocking line filter of the present invention, the following is a description of a preferred, but not limiting embodiment with reference to the attached drawings, in which:

Figure 1 is an enlarged section of a linear filter section having gaskets inserted in recesses or continuous channels defined on and held on opposite surfaces of the turns of the coil forming the filter;

Figure 2 is a longitudinal section of a linear filter, the multi-beam supports of which are held together and compressed towards each other by threaded rods made of fiberglass, while their free ends are held on the corresponding multi-beam supports only with nuts and locknuts.

Figure 1 presents a perspective view in cross section of a section of a winding or solenoid formed by a continuous spiral of turns of a coil of electrically conductive metal with corresponding gaskets forming part of a blocking linear filter, other parts and components of which are omitted, since their structure is well known and obvious to specialists in this technical field.

Description of the preferred embodiment

The drawing shows three sections of the turns of a metal coil 1 (wound as a solenoid in a linear filter), held separately from each other by spacers 2 of insulating material. The gaskets can be formed as separate parts or sections, but mounted together as a continuous spiral, while the turns are formed of a continuous wire of conductive metal (for example, aluminum or copper) wound so as to form a continuous spiral with many side-by-side coils separated gaskets 2.

The main distinguishing feature of the linear filter to which the present invention relates is that the turns of the coil 1 have a substantially H-shaped cross section, while the central portion 1A is substantially flat and has two side flanges 1B and 1C, which together define (on each side of the turns of the coil 1) a continuous recess or channel (which may diverge slightly outward at the free ends of the flanges 1B and 1C) into which the gaskets 2 are inserted and which are adjacent to each other to form a continuous a spiral that holds the spiral coils 1 firmly attached to each other to prevent axial or lateral displacement or deformation. The inner and outer surfaces of spirals 1 and 2 can be coated with two-component cold cured epoxy. Thus, a linear filter can be obtained that meets the most stringent requirements of the IEC 353 standard of 1989.

Figure 2 schematically partially shows a linear filter, the spiral of which is generally indicated by 10. This spiral 10 is held and firmly fixed between two end metal multipath supports (the upper of which is indicated by 11 and the lower by 12) of a known type, while in the supports 11, 12 holes are made from which the ends 13A of the plurality of rods 13 protrude.

Each rod 13, 13A of the present invention is made of continuous fiberglass rods 13 impregnated with resin and having a thread along its entire length or at least in those sections 13A that extend outward or outside the multipath supports 11, 12.

The nuts 14 (with locknuts) are screwed onto the threaded ends 13A of the fiberglass rods, resting on the outer surfaces of the multi-beam supports 11, 12 and exerting very high pressure on them, which ensures the dimensional stability of the line filter on which they are mounted.

Fiberglass rods not only have a very simple design and have high tensile strength, but are also very easy to assemble, inexpensive and do not require the use of any system of electrical insulators designed specifically for them.

Claims (4)

1. A linear filter for transmission systems on medium / high voltage alternating current power lines, comprising a continuous coil of conductive metal made in series with a medium / high voltage line, wherein the metal coil is formed by at least a continuous spiral made from turns (1, 1A, 1B, 1C) of the coil, which are wound as a solenoid and held apart by a sequence of gaskets (2) made of electrically insulating material, characterized in that the turns (1, 1A, 1B, 1C) of the coil are essentially H-shaped so as to define a recess or continuous channel on each of the opposite surfaces of such coil turns, in which the gaskets are placed and held (2 ), while the gaskets (2) create a reliable support for each coil coil with a coil coil adjacent to it in a continuous spiral of coil coils. 2. A linear filter according to claim 1, characterized in that the gaskets (2) are made so as to form a spiral held in opposite channels or recesses of two turns (1, 1A, 1B, 1C) of the coil facing each other. 3. The linear filter according to claim 1 or 2, characterized in that it is held between two metal multi-beam supports (11, 12), firmly connected to each other by rods (13, 13A) made of continuous fiberglass impregnated with resin, having a thread, wherein at least two ends (13A) of each rod (13, 13A) are threaded in at least those sections that protrude outward or behind these multi-beam supports (11, 12) on which these rods are held with nuts (14) screwed onto the threaded ends (13A) of these rods. 4. The linear filter according to claim 3, characterized in that the rods (13, 13A) made of resin and fiberglass have threads along their entire length.

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