RU37436U1 - HIGH VOLTAGE DC MULTI-WIRED DC ELECTRIC TRANSMISSION LINE - Google Patents

Abstract

1. A multi-wire overhead DC power line of high voltage DC, containing supports with traverses and wire-resistant, live wires suspended to traverses, and three lightning protection cables suspended on wire-racks above current-carrying wires, characterized in that two lightning protection cables are located at the edges of the support and are removed further away from it than any current-carrying wire, and the third lightning protection cable is suspended along the axis of symmetry of the support. 2. The line according to claim 1, characterized in that the lightning protection cables are suspended at the same level. The line according to claim 1, characterized in that the central lightning protection cable is suspended above or below the side cables.

Description

DC multi-wire overhead power line

high voltage

The utility model relates to multi-wire overhead DC power lines of high voltage, used in the main circuits of DC networks at the approaches to converting substations.

Known multi-wire overhead lines (OHL) of direct current containing poles of OHL, additional wires for returning unbalance current and lightning protection cables

The closest analogue selected as a prototype for the proposed model is utility model No. 15821 under the heading IPC HO2J 1/00 High-voltage direct-current overhead line (authors V.I. Galanov, D.E. Kadomsky, N.N. Tikhodeev , BC Miraculous), which considers a multi-wire overhead line containing one or two additional current-carrying wires suspended below the main working wires and serving for a metal return of unbalance current. In the existing prototype, one or two lightning protection cables are used, suspended on cable racks above current-carrying wires and offset from their axis by an arbitrary angle.

In the existing prototype there is no information about improving the efficiency of lightning protection of overhead lines when approaching a converter substation in order to protect equipment from lightning surges that occur when lightning breaks at the poles of overhead lines near the substation.

Utility Model Essence

The purpose of constructing a useful model of a section of multi-line OHL of power transmission of direct current is to protect the linear reactors of converter substations and the substations themselves from incident from the side of the OHL of direct current of thunderstorm waves by drastically reducing the likelihood of lightning breaking through the poles of a line section of about 20 km in length when approaching the substation and increasing thereby, its lightning resistance. At

IPC H02J1 / 00, 1/08, H02g7 / 00, 7/20 Object - utility model

lightning strike outside the protected area, the amplitude of the wave incident on the substation has a smoothed front and a reduced amplitude, which helps protect the substation equipment from overvoltage.

This goal is achieved by the fact that the lightning protection system of a multi-wire overhead DC power line is formed by three lightning protection cables, one lightning protection cable suspended above the central part of the support, and the other two removed from the central axis of the support further than the current-carrying wires.

To implement in the form of a utility model of a multi-wire high-voltage direct current overhead line, it is necessary to determine

1) a constructive arrangement of poles of different polarity on the support;

2) a constructive arrangement of lightning protection cables on a support;

3) constructive suspension of lightning protection cables on a support;

4) the relative position of the poles and lightning protection cables, taking into account the electrical strength of the air insulation gaps.

The task of creating a useful model of a multi-wire overhead DC power line of a high voltage direct current is solved on all points (1-4) based on computational studies.

List of figures (drawings)

Further presentation is illustrated using Fig. 1 and Fig. 2, which shows the suspension system of wires and cables on a multi-wire overhead DC power line and Fig. 3, which shows a graph of the deformation and attenuation of lightning overvoltages in overhead lines.

In fig. 1 schematically shows the suspension of wires and three lightning protection cables on a support of a bipolar DC overhead line in accordance with the utility model.

Figure 2 shows an example of the implementation of the suspension of wires and three lightning protection cables on a support of a double-circuit (quadrupolar) DC VL in accordance with the formula of the utility model.

Information confirming the feasibility of implementing a utility model

In accordance with the proposed utility model, a multi-wire bipolar DC overhead power line (Fig. 1) contains two conductive wires (poles) of different polarity (1 and 2) and three lightning protection cables (3, 4 and 5).

tiers, and three lightning protection cables (3, 4 and 5). At the same time, both the same potential and the opposite potential can be applied to the poles of one tier.

The placement of the negative poles of the same name in the lower tier creates a favorable ecological situation near the line due to the predominance of negatively charged ions on the earth flowing from the corona poles and having a certain concentration positive effect on humans. With this scheme of supplying potential to the poles, the specific number of lightning blackouts of the positive pole of the quadrupolar line (per 100 km of the line and 1 year of its operation) should not exceed 10, this indicator is achieved by a special mutual arrangement of lightning protection cables and poles (the protection angle a and the excess of cables are optimized above the poles on the support D /), sharply reducing the final orientation of the lightning to the upper positive pole of the line.

Placing the negative poles of the same name in the upper tier will provide high lightning resistance of the quadrupolar line, since the probability of lightning being oriented to the negative poles of the quadrupolar line is close to zero.

The placement of poles of different polarity in each tier will make it possible to reduce the electric field strength near the earth in comparison with the supply options of the same potential to the poles of each tier.

All wires are suspended on supports having axial symmetry, through insulators with clamps for attaching the wires at the required insulation distances.

The difference between the considered multi-line overhead line from the specified prototype is that:

- a lightning protection system is formed by three lightning protection cables;

- one lightning protection cable is suspended along the axis of the support;

- two other lightning protection cables are removed from the axis of the support farther than current-carrying wires;

-additional wires for returning unbalance current are absent. The listed differences and features of the utility model of a multi-wire line

create a number of new advantages:

-increasing the efficiency of protecting the poles of the line from lightning breaks;

- when lightning strikes a pole of the line outside the protected area (further 20 km from the substation), a thunderstorm incident on the substation has a smoothed front up to 10 μs and an amplitude reduced by 20-40% (Fig. 3), which allows reliable protection of the linear reactor and substation surge protection.

The implementation of the utility model is accompanied by a slight increase in the mass of steel on the support, since the cable resistance of the central lightning protection cable has a small mass and this cable does not create bending moments relative to the axis of the support, and the approach length is not more than 5% of the total length of the overhead line

The proposed design of the multi-wire line is recommended not to be used along the entire length of the overhead line, but only on its short section (about 20 km) near the converter substation (linear reactor) for their direct protection against incident lightning waves, therefore, the total cost of overhead lines during the implementation of the proposed design practically does not increase .

A multi-wire overhead line, made in accordance with the formula of this utility model, will provide radical protection of the poles of the line from lightning breaks and effective smoothing of the steep front of a thunderstorm wave, which allows reliable protection of the reactor and converter substation from lightning waves incident from the side of the line.

The authors

Literature

1. Utility model No. 15821 IPC H02J, 1/00; H02g7 / 00, 7/20 Multi-wire overhead

high voltage direct current line (authors: V.I. Galanov, D.E. Kadomsky,

N.N. Tikhodeev, B.C. Marvelous). A.A. Boyko N.B. Kutuzova A.N. Novikova N.N. Tikhodeev

Claims (3)

1. A multi-wire overhead DC power line of high voltage DC, containing supports with traverses and wire-resistant, live wires suspended to traverses, and three lightning protection cables suspended on wire-racks above current-carrying wires, characterized in that two lightning protection cables are located at the edges of the support and are removed further away from it than any current-carrying wire, and the third lightning protection cable is suspended along the axis of symmetry of the support. 2. The line according to claim 1, characterized in that the lightning protection cables are suspended at the same level. 3. The line according to claim 1, characterized in that the central lightning protection cable is suspended above or below the side cables.