SU1591110A1

SU1591110A1 - Method of conducting preparator work for phase-wise repairs of power line

Info

Publication number: SU1591110A1
Application number: SU874353231A
Authority: SU
Inventors: Semen S Klyamkin; Aleksandr S Krasnoshtanov; Viktor E Ponimatkin; Vladimir N Semenov
Original assignee: Nii Peredache Elektroenergii P
Priority date: 1987-12-30
Filing date: 1987-12-30
Publication date: 1990-09-07

Description

The invention relates to power engineering and is intended for the repair and operation of high-voltage power lines. The purpose of the invention is to increase the efficiency and safety of work, reducing the electromagnetic influence of the line. Between the disconnected phase of the line and the earthing of the terminal substations include elements whose resistance is chosen from the condition of minimizing the voltage at the point of the disconnected phase in which any work is to be carried out.

The invention relates to power engineering, and in particular to methods of repair of high-voltage equipment of existing transmission lines (PTL).

The aim of the invention is to increase the efficiency and safety of work, reducing electromagnetic

line effects by reducing currents in

ι

ground .;

The proposed method is as follows.

Turn off the line phase on both sides. The disconnected phase is grounded at the ends through resistance elements that are specially selected, impose a protective grounding at the workplace, using the device to ensure the permissible level of touch voltage. If there is a communication connection between the linear team and the substation personnel, it is desirable to quickly adjust the resistance at the substations to minimize the touch voltage in safe area.

The works are carried out according to the existing technological cards for phase-by-phase repair included in the maintenance documentation of the power transmission lines.

The voltage induced on the disconnected phase of power lines at point X can be represented as a sum of two components:

ύ (χ) = and 5 + ύ _Μ (χ),

3

1591110

four

• Where ύ ₉ is the voltage due to

electrostatic effect;

- electromagnetic component. five

To reduce the first component, the resulting resistance (at parallel addition) of the elements connected at the ends of the repaired phase of the elements is selected (taking into account the resistance of grounding)

^ζ NG ^Ζ Μ2

^Ζ ρ ⁼ ^Ζ _"η 7 ^{^{^{+ Ζη2; Ζ ηΓ Ζ» +}}} Ε 31 ^'Ζ Η2 ⁼

= 7 + ΐ) 15

^α α ^κ 32 '

where Ζ ^ is the resistance of the element connected between the phase and the grounding conductor of the first substation; 20

·. · 'Ζ ^ - element resistance,

connected in the same way at the second substation;

^K e <

IR ^ d, - grounding resistance of 25 substations.

The selection is carried out in such a way as to reduce the electrostatic effect of non-disconnected phases to the level

less admissible contact voltage. For this you need to have

^Ζ Ήι ' ^Ζ Η2 I ^and lr.D, op Ζ _Η 1+ ^Ζ Η2Ι CRYSDD *

(one)

35

where ϋ

etc. Extra and _t

allowable touch stress; line phase voltage;

6) = 2 (1Г ~ angular frequency of current in

lines;

With _DV - running capacity between the disconnected and disconnected phases;

1 - line length.

The electromagnetic component of the voltage induced at the point of production, at a distance X from the tires of the first substation can be 45

50

razhen in the form

and _m (x)

Where B,, _{ζ ζ}

~ ζ-2 ^ ζ

Υ <+ Υ

longitudinal EMF induced on a disconnected wire on opposite sides of point X;

Υ ₄ , ₂ are the input conductances of the corresponding sections from the side of point X.

EMF 6, and ζ _{g are} proportional to the lengths of the wire sections

⁼ E _o X;

ε ₂ = e ₀ (1-x),

where Εθ is the emf induced in a unit of length.

Input conductances depend on the length of the sections, as well as on the terminal resistances

V C ----, (3)

Ζ (1-Χ) + Ζ _Η2

where Ζ ¹ - longitudinal longitudinal resistance of the wire.

Expressions (2) and (3) together lead to _m (X ₀ ) = 0, if the ratio of the resistances at the ends of the line satisfy the condition

ζ _Η) . X

Together with (1), this condition allows one to determine the magnitudes of the total resistances Ζsc and Ζ ^ 2> and, according to them, the values of the resistances of the elements included in substations. With this choice of resistance as the distance from point X along the line at a distance (X ₍₍ -X) voltage on the wire relative to the earth is calculated by the law

40

and _m (x)

^Ζ Η < ^{+ Ζ} Η2

7 " ₀ (Χ, -Χ)" ¹ 1

Ε _Ο (Χ ^ ~ Χ),

^Ζ ΗΙ ^{+ Ζ} Η2 ^{+ Ζ} 1 ^Ζ ΗΙ + ₄₂ Ζ '1

those. much slower than in the case of a non-instance at the ends of the wire.

When using the proposed method, the following advantages are achieved:

electrical safety is ensured at virtually any resistance protective grounding at the workplace;

a special isolating rod-absorber is excluded from use for applying protective grounding on lines of practically any voltage class;

(2)

55

the expansion of the size of the safe zone to several kilometers is provided.

In this case, it is possible to carry out phase-by-phase repair on all high-voltage lines in areas with low electrical conductivity of the soil, where the necessary resistance of protective Grounding at the workplace is practically unattainable.

When carrying out phase-by-phase repairs according to the invention, under normal conditions, the efficiency of preparatory work is increased by saving time on the protective earthing device, speed of repair work due to the possibility of simultaneous work of several crews (extension of the safe zone). 20

Safety is increased by reducing the induced voltage in the workplace.

Claims

Claims 25

The method of carrying out preparatory work for the phase-by-phase repair of a high-voltage transmission line connecting two substations equipped with 39

1591110

6

in order to increase the efficiency and safety of work, reduce the electromagnetic effect of the line by reducing currents in the earth, before applying grounding, an element with a resistance = Ζ ^, - Κ ^ is connected between the disconnected phase and the grounding conductor of the first substation and an element with a resistance Ζ ^ = _Η1 -Ε off ^between phase control and earthing second substation where the quantities Ζ ^ _(Ζ and w satisfy the relations Ζ XI Ζ μι 'Hts2 IV etc. Additional ^{ζ;. ϊ = ΐ-χ} ' I Ζη / ΖμΓ ΰφ "ώδΐ"'

where X is the distance from the first substation to the work site;

1 - line length; ϋ pr. Dop “permissible contact voltage;

H ~ - phase line voltage;

63 - the angular frequency of the current in

lines;

C - the total value of running capacity between the disconnected and disconnected phases;

K to. - the values of the earthing resistances of the first and second substations, respectively.