RU2277743C2 - Double-circuit power transmission line - Google Patents

Abstract

FIELD: electrical engineering; power transmission lines.

SUBSTANCE: proposed high-voltage double circuit power transmission line that has vertical arrangement of phases and different pulse strength of conductor suspension insulating structures on power transmission line phases incorporating sections without ground wire protection as well as sections with high resistivity of soil is characterized in that pulse strength of suspension insulating structures on two upper phases is higher than that on other phases. Phases in which pulse strength of conductor suspension insulating structures is lower relate to one circuit of power transmission line. In addition, conductor suspension insulating structures on two upper phases of power transmission line can be made in the form of long-stick polymeric insulators and those on other phases, in the form of cap-and-pin insulator string of equal face-to-face length; suspension insulating structures of lower pulse strength may be used only on two upper phases of power transmission line sections having no ground wires or on its sections with high soil resistivity.

EFFECT: enhanced reliability of power transmission.

1 cl, 1 dwg

Description

The invention relates to the field of electrical engineering, in particular to power lines (power lines), and can be used on double-circuit power lines, the route of which passes through areas with soils of high resistivity, as well as in areas of power lines without lightning protection cable.

A technical solution is known in which each of the phases of a double-circuit power transmission line has the same insulating suspension structure (ICP) of wires, for example, a string of insulators [1].

The disadvantage of this technical solution is that at high resistivities of the soil along the power transmission line, its lightning protection and reliability of power supply through it decrease, because with increasing voltage on the support, it is possible to overlap the insulation on both power transmission lines and turn them off.

There is also a technical solution for a double-circuit power line with lightning protection cables and overhead arresters parallel to the garlands of insulators [2], adopted as a prototype. The phases of this power line have different pulsed strength of the ICP wires to ensure that one of its chains remains in operation during a thunderstorm damage to the power line.

The disadvantage of this technical solution, in addition to the complexity of the device and its increased cost, is that a suspended arrester reduces the voltage only on a string of insulators, in parallel to which it is connected, but not on a support. Therefore, on other supports (without arrester), the phase isolation of the second circuit can overlap and, therefore, the two circuits of the double-circuit power line are disconnected.

The aim of this invention is to increase the reliability of power transmission, the route of which passes through areas with high values of resistivity of the soil or in certain areas without cable protection.

This goal is achieved by the fact that the double-circuit high voltage power transmission line (LEP) with a vertical phase arrangement and with unequal impulse strength of the insulating suspension structure (IKP) of the wires on the LEP phases, containing sections without cable protection, as well as sections with high ground resistivity, on the two upper phases of the ICP wires with lower impulse strength than on the other phases. In this case, the phases with reduced pulsed strength of the ICP wires belong to the same power line circuit. In addition, ICP wires on the two upper phases of power lines can be made in the form of long-rod polymer insulators, and on the rest - in the form of a garland of plate insulators of the same building length and ICPs on the two upper phases of power lines can be made with reduced impulse strength only in areas of power lines, not protected by a lightning protection cable, or in areas of power lines with high soil resistivity.

The drawing shows a schematic diagram of this device. The support of a double-circuit power line has a rack (1) and a traverse (2) to which a cable (3) and wires are attached, and the ICP of the wires located at the top of the support (4) have lower impulse strength than the ICP of wires located below (5) .

The essence of the invention lies in the fact that with increasing voltage during a lightning strike both in a support or cable, and in the wire and the ICP of one of the wires, the ICP of the other wires overlaps, if it occurs, either on the other phase of the same circuit of the same support or on phases of the same circuit on another support.

In the case of a lightning strike with a large current in the support at high specific ground resistances, the voltage on the cross-arms (2) increases and, therefore, the voltage on the ICP of the wires of both power transmission lines increases. The difference in the pulse strength of ICPs of different designs with the same rated voltage can be 20%. In this case, the probability of disconnecting both circuits of a double-circuit line according to expert estimates is reduced by 1.7-2.0 times, and the disconnected state of one circuit lasts only during a pause of AR or OAPV. The second circuit remains in operation, which increases the reliability of power transmission.

In areas of power lines without cable protection, the two upper phases of the power lines must belong to the same circuit. In this case, they will perform the functions of a lightning protection cable to protect the circuit from lightning strikes, the phases of which are located below. When lightning strikes a wire in areas without a cable, the ICP of the affected wire will overlap, and at high values of soil resistivity, there will also be an increase in voltage on the ICP of neighboring supports, the overlap of which on the circuit with reduced impulse strength will occur until the voltage on the affected lightning the wire will not become less than the pulse strength of the ICP of this wire.

It should be noted that on double-circuit power lines, which are connected at one end to one substation, to increase reliability, high-frequency communication for relay protection is carried out in a parallel circuit. Therefore, maintaining high impulse strength in the third phase is necessary to provide relay protection of the other circuit with high-frequency coupling.

The application of this technical solution is possible both in the construction of a new power transmission line, and in the reconstruction or technical re-equipment of a previously constructed power transmission line. When constructing a new power line, it may be necessary to implement sections of the line without a cable, and taking into account the increase in the calculated grounding resistances of the supports may be required during the reconstruction of the existing power line.

Information sources

1. Catalog of standardized and standard supports. Meye USSR, GlavNIIproekt, SZO ESP, Leningrad, 1985. - No. 5713tm-t3. Unified steel intermediate supports 220 kV for mountainous regions, No. 5713 tm t 3-43.

2. Mogilevsky L.Z., Yurikov P.A. Lightning protection of double-circuit power lines. // Electricity, 1973. No. 4. - S.92-93.

Claims (3)

1. A double-circuit high voltage power transmission line (LEP) with a vertical arrangement of phases and with unequal impulse strength of the insulating suspension structure (IKP) of the wires at the LEP phases, containing sections without cable protection, as well as sections with high ground resistivity, characterized in that the IKP wires in the upper two phases of these sections of the transmission line has a lower impulse strength than in other phases. 2. The device according to claim 1, characterized in that the phases with reduced impulse strength of the ICP wires belong to the same power line circuit. 3. The device according to claim 1 or 2, characterized in that the ICP wires on the two upper phases of the power lines are made in the form of long-rod polymer insulators, and on the rest - in the form of a garland of plate insulators of the same building length.