Transition point of cable-overhead line with a service platform made using dielectric material

Abstract

FIELD: power transmission lines.SUBSTANCE: invention relates to a transition point of a cable-overhead power transmission line with a service platform, comprising a support equipped with cross-arms with insulators, adapted for connecting with wires of the overhead power transmission line, and a cable joint, adapted for connecting a cable power transmission line with a wire of the overhead power transmission line for each phase. For this purpose, the service platform is attached to the support and is designed to accommodate primary equipment. The service platform provides the ability to pass through the cable of each phase. At least a portion of the service platform is made using a dielectric material to provide an open circuit around the location for the cable of each phase to pass through the service platform.EFFECT: elimination of a closed magnetic circuit around the cable of each phase, thereby eliminating energy losses, electromagnetic interference and risks to personnel.8 cl, 2 dwg

Description

[0001] A transition point of a cable-overhead line with a service platform made using dielectric material relates to electrical engineering, in particular to transition points intended for the transmission of electric power from an overhead section of a line to a cable section of a power transmission line, or vice versa: from a cable section to an overhead section.

[0002] Patent RU 2739911 describes a digital transfer point consisting of a pole equipped with crossbars for suspending transmission line wires, cable joints for organizing cable entries, and service platforms for primary and secondary equipment attached to the pole. Cables that are part of the transmission line and connected to the overhead power line wires via cable joints pass through the service platforms.

[0003] A disadvantage of the known transition point is that the service platforms, usually made of metal, form closed magnetic circuits around the cables passing through them, which, at high voltages in AC power lines, will lead to significant power losses, electromagnetic interference and risks for personnel.

[0004] The objective of the invention is to eliminate closed magnetic circuits in service areas around cables.

[0005] The technical problem is solved by using a cable-overhead power line transition point with a service platform. This platform comprises a support structure equipped with crossarms with insulators designed to connect to the overhead power line conductors and a cable joint designed to connect the cable power line to the overhead power line conductor for each phase. The service platform is attached to the support structure and is designed to accommodate primary equipment. The service platform allows the cable for each phase to pass through it.

[0006] A distinctive feature of the present invention is that the entire platform or sections of the platform from the places for cables to pass through it to its edge are made of a dielectric material, providing an open circuit around the place for the cable of each phase to pass through the platform.

[0007] To ensure an open circuit, the entire service platform can be constructed using dielectric material. Alternatively, to ensure an open circuit, it may be sufficient to construct the section of the service platform from the cable entry point to its edge using dielectric material. The primary equipment preferably includes a vertical disconnect switch with grounding conductor, a surge suppressor, and a digital optical current transformer for each phase of the power line.

[0008] The transition point may include an additional service platform attached to the support below the primary equipment service platform. It may be designed to accommodate secondary equipment. At least part of the additional service platform may preferably be constructed using a dielectric material, providing an open circuit around the area for the cable of each phase to pass through the service platform.

[0009] To ensure an open circuit, the entire auxiliary service area may be constructed using dielectric material. Alternatively, to ensure an open circuit, it may be sufficient for the section of the auxiliary service area from the cable entry point to its edge to be constructed using dielectric material. The secondary equipment may preferably include control and communication equipment.

[0010] The technical result of the invention is the elimination of the closed magnetic circuit around each phase cable. This eliminates power loss, electromagnetic interference, and risks to personnel.

[0011] The invention is explained by drawings, where Fig. 1 shows a general view of the transition point, and Fig. 2 shows a top view of the service platform in one of the embodiments.

[0012] The invention is further described with reference to the explanatory drawings, which illustrate one possible embodiment using a three-phase power line as an example. The embodiments disclosed in the description are not limiting and are intended to illustrate the essence of the invention. The scope of protection is limited only by the claims. Since modern power transmission lines are primarily three-phase, and therefore, a transition point must contain three sets of necessary equipment, the embodiment of a transition point for a three-phase network falls within the scope of protection limited by the claims. At the same time, the scope of protection of the invention also includes lines with other numbers of phases—single-phase, two-phase, etc.

[0013] The invention is illustrated by a transfer point with two service platforms. However, the scope of protection of the invention also includes transfer points with one or more service platforms. Therefore, in these cases, the transfer point depicted in the figures can be considered to have one service platform (in which case one of them, the lower one, must be excluded) or additional platforms. The service platform intended for the primary equipment may be called the upper platform or simply a platform, while the service platform intended for the secondary equipment may be called the lower platform or additional platform.

[0014] A transition point for an overhead power transmission line with control equipment, as shown in Fig. 1, comprises a support 1 with platforms 2 and 3. Structurally, the support 1 can be made in different ways, in particular from metal, for example, steel, or concrete. The support 1 is preferably installed on a foundation that can be made in the ground and can partially extend out of the ground or can be located on the ground surface. Platforms 2, 3 are located one above the other at different levels depending on the operational requirements. In particular, the lower platform 3 can be located several meters above the ground level, and the upper platform 2 - several meters above the level of the lower platform.

[0015] Platforms 2 and 3 may be open or closed. In Fig. 1, lower platform 3 is closed, while upper platform 2 is open. In certain embodiments, platform 2 may be enclosed with a protective mesh fence to prevent tools from falling off the platforms or electrical equipment from flying off in the event of an emergency, and to allow visual observation of the electrical equipment located there.

[0016] Thanks to the enclosed nature of lower platform 3, personnel can monitor the operation of the crossing point in a comfortable environment, protected from direct exposure to environmental factors such as wind, rain, snow, and sunlight. Monitoring the operation of the crossing point involves monitoring the operating parameters of the crossing point equipment and / or controlling its operation. To facilitate servicing of electrical equipment located on platforms 2 and 3, a staircase with access to the platforms can be located inside the support.

[0017] Post 1 is equipped with a crossarm 4 with an insulator. Fig. 1 does not show the insulators and overhead power line conductors. A disconnector may be installed on the top platform 2 of post 1. This disconnector is connected via busbars on one side to the overhead power line conductor and to a surge suppressor on the other. It can also be connected via additional wires and / or busbars to a cable joint. The cable joint is connected to a cable that descends along the post to the ground and then into the earth.

[0018] A surge arrester, also connected to a cable joint, is designed to limit short-term overvoltages, which are voltage spikes. Such surges can occur, for example, as a result of lightning strikes on or near a power line, including in the overhead section of the power line and / or at a transition point. The presence of a surge arrester reduces the impact of short-term voltage spikes on electrical equipment connected to or included in the power line.

[0019] A disconnector is an electrical switching device that ensures the closing and opening of connecting contacts as a result of the movement of the closing contact, caused, for example, by the disconnector's actuator. Thus, a disconnector enables the connection or disconnection of a transmission line conductor and cable 6 through intermediate connecting conductors and / or busbars and / or other elements and equipment of the transition point. The connection of the conductor and cable is necessary for the transfer of electrical energy from the overhead section of the transmission line to the cable section or vice versa.

[0020] The transfer point may also be provided with an earthing conductor configured to earth the contact electrode electrically connected to the surge arrester and the cable after the disconnector is opened to protect the transfer point equipment and the cable transmission line from overvoltage.

[0021] A digital optical current transformer (OCT) can also be installed at site 2 to measure the current flowing through the disconnector. The sensing element of the OCT can be located on the busbar carrying the current flowing through the disconnector. The sensing element contains a sensitive optical fiber in a quartz tube that detects the magnetic field generated by the current flowing along the busbar and, consequently, through the disconnector. The OCT measurement data, received from the optic fiber and further processed if necessary, can be transmitted to the control room. Based on this data, the control room can control the disconnector's operation.The presence of an optical current transformer in the transition point ensures protection of the cable line and electrical equipment connected to the power line or included in it from current surges, including long-term ones, in the power line caused, for example, by short circuits in the cable section.

[0022] All power equipment on the upper platform 2, including the disconnector, optical current transformer, surge arrester, and cable joint, may be considered primary equipment. Platform 3 houses secondary equipment, which may include control (monitoring and management) and communications equipment.

[0023] Both service platforms are preferably located above ground level. To allow personnel access to these platforms, the support structure may be equipped with doors, with a ladder between them inside the support structure. This allows personnel to enter the support structure through the lower door, ascend the ladder to the middle or upper door, and exit to the lower or upper platform, respectively. Alternatively, the ladders may be located outside the support structure, with openings in the platforms for personnel to pass through.

[0024] Fig. 2 shows the upper platform 2 in a top view. It shows how support 1 rises above platform 2 with crossarms 4, to which the overhead power line wires are attached. The overhead power line wires are connected using cable joints to cables 5 (Fig. 1) of the power line. Cables 5 descend along support 1 down through the platforms and into the ground. In Fig. 2, you can see places 6 for cable passage through platform 2.

[0025] When service platforms are made of metal (e.g., steel, duralumin, etc.), closed magnetic loops form around the cables passing through them. At high voltages and high currents in AC power lines, strong currents will be induced around the cables in the platforms via electromagnetic induction, leading to significant power losses, electromagnetic interference, and risks to personnel. To eliminate these losses and risks, it is necessary to break these loops around the cables.

[0026] For this purpose, the entire platform or sections of the platform from the cable entry points to its edge are made of dielectric material, ensuring an open circuit around the cable entry point for each phase. In one embodiment, the entire platform can be made of dielectric material, in which case the circuit will be open due to the impossibility of forming one.

[0027] In another embodiment, to ensure an open circuit, it may be sufficient, as shown in Fig. 2, for section 7 (highlighted in black) of the service platform 2 from the place 6 for passing the cable through it to its edge to be made using a dielectric material. Such section 7 is necessary for the cable of each phase, as shown in Fig. 2.

[0028] The dielectric material may be polymeric, composite, or other materials known in the art that possess sufficient dielectric and strength properties. For example, this may include fiberglass, carbon fiber, fiberglass, etc. Sufficient mechanical strength can be ensured by the thickness and / or profiling of the inserts placed in sections 7. Attachment of such inserts to platform 2 may be accomplished by means and methods known in the art, such as adhesive bonding, bolting, or self-tapping screws.

[0029] The transition point may comprise an additional service platform 3 attached to the support 1 under the service platform 2 for the primary equipment. It may be intended for accommodating secondary equipment. Since cables 5 (Fig. 1) also pass through it, at least a portion of the additional service platform 3 may advantageously be constructed using a dielectric material, providing an open circuit around the place for the cable of each phase to pass through the service platform.

[0030] To ensure an open circuit, the entire additional service platform can be constructed using dielectric material. Alternatively, to ensure an open circuit, as with platform 2, only the section of the additional service platform from the cable entry point to its edge can be constructed using dielectric material.

[0031] The present invention eliminates power loss, electromagnetic interference and risks to personnel.

Claims

1. A transition point for a cable-overhead power transmission line with a service platform, comprising a support equipped with crossarms with insulators, made with the possibility of connection with the wires of the overhead power transmission line, and a cable joint, made with the possibility of connecting the cable power transmission line with the wire of the overhead power transmission line for each phase, wherein the service platform is attached to the support and is made with the possibility of placing primary equipment on it, wherein the service platform provides the possibility of passing through it the cable of each phase, characterized in that the entire platform or sections of the platform from the places for passing cables through it to its edge are made of a dielectric material with the provision of an open circuit around the place for passing through the service platform the cable of each phase.

2. A transition point according to paragraph 1, characterized in that the entire service area is made using a dielectric material.

3. A transition point according to paragraph 1, characterized in that the section of the service platform from the place where the cable passes through it to its edge is made using a dielectric material.

4. A transition point according to paragraph 1, characterized in that the primary equipment includes a vertical disconnector with an earthing switch, a surge suppressor, and a digital optical current transformer for each phase of the power transmission line.

5. A transition point according to paragraph 1, characterized in that it is provided with an additional service platform attached to a support under the service platform for the primary equipment and intended for placing secondary equipment, wherein at least part of the additional service platform is made using a dielectric material with the provision of an open circuit around the place for passing through the service platform of the cable of each phase.

6. A transition point according to paragraph 5, characterized in that the entire additional service platform is made using a dielectric material.

7. A transition point according to paragraph 5, characterized in that the section of the additional service platform from the place for the cable to pass through it to its edge is made using a dielectric material.

8. The transition point according to paragraph 5, characterized in that the secondary equipment includes control and communication equipment.

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