SU1550440A1 - Method of unilateral determination of distance to the place of unstable single-phase short-circuit in electric power with single-phase automatic reclosing - Google Patents

Abstract

The invention relates to electrical engineering. The purpose of the invention is to improve the accuracy of measuring the distance to an unstable single-phase short circuit. At the moment of a short circuit, a measurement is made from one end of the power line of the phase currents and voltages and their values of the resistance of the short circuit loop and the phase angle are determined. The determination of the current value of the equivalent resistance of the zero and inverse sequences of the supply system, achieved by measuring phase currents and voltages at the monitoring point after a successful single-phase re-connection of the line from the opposite end to its inclusion from this end, improved the accuracy of measuring the distance to the short circuit. by eliminating the effect of transient resistance on the control result. 2 Il.

Description

The invention relates to electrical engineering and can be used in the implementation of devices for determining the distance to a place of damage (OMP) on power lines equipped with a single-phase reclosing device.

The aim of the invention is to improve the accuracy of one-way OMP.

According to the method involving measurement of phase currents and voltages at the monitoring point from one end of the transmission line in the short circuit mode, phase voltages and currents at the monitoring point are measured after a successful single-phase automatic reclosing (OAPV; lines from the opposite end before switching on of this end, according to the results of additional measurements, determine the equivalent resistance of the zero (inverse) sequence of the feed system from the opposite end of the line, and the distance to the short circuit location is calculated by based on its current value.

ate

about

4b

Due to the additional measurements of currents and voltages in the OAPO cycle, it is possible to determine the parameters of the system from the opposite end of the line, which correspond to the actual values at the moment. The introduction of this value into the calculated expression for the OMP instead of the average value of the system resistance T0 applied from the opposite end of the line allows to significantly improve the accuracy of determining the distance to the short circuit.

Figure 1 shows the block diagram 15 of the device for the implementation of the proposed method; Lig.2 - equivalent transmission line replacement circuit for components of zero (reverse) sequence.

On Lig.2 the following notation is accepted:

- zo (2.) equivalent resistances of the zero (reverse) sequence of the system of the opposite end of the 25 line without taking into account the resistance of the linear reactors installed at the end of the line;

O (2) with o (i) C2. - equivalent snot 13, the block diagram also shows the linear reactors 14-16 and switches 17-19 in each Laz transmission line.

The method is implemented as follows.

In the event of a short-circuit program starting body, analyzing the current level values of the phase currents, obtained by means of an input unit 5, to the inputs of which the outputs of voltage and current transformers 1-4 are connected, writes 12 codes corresponding to the integral value m values of phase currents and voltages. These values are recorded in the RAM of the microcomputer 12 at an interval that turns off the damaged mode (Lazy and its activation mode by the OAPV device that is equipped with a controlled line. Then, by the values of the phase currents and voltages in the activation mode of the damaged phase from the opposite end of the line until switching it on from the control side, determine the parameters of the system from the opposite end of the line against the zero (reverse) sequence of the Bb1Razhdeniyu system of systems adjacent to the place of control and to the opposite ozhnomu (r) C

the end of the line, respectively;

 ..fijSLLHsi H JLsi2L, I.ouL

2o (g) but (g)

+ Ј o (4) 1-0 (2)

2po (i) reactances

HGde A

zero (reverse) sequence - jc o (g)

linear reactors connected at the ends of the line in each phase;

o (a) –U 0 (4) lo () O o («-) currents and voltages of zero (reverse) sequence at the control point and from the opposite end of the line, respectively;

A.OU) Јo (g) f.) Ro (g) are coefficients describing the parameters of the zero (inverse) sequence of the transmission line, represented as a quadrupole, in the case of a long line, they can be expressed in terms of hyperbolic functions .;

Ueo (2) is an equivalent source of electromotive force (EMF) that compensates for asymmetry at the end of the line with the phase cut off in the OAPO cycle.

The device (Fig. 1) contains a voltage transformer 1, current transformers 2-4 installed in each phase of the line, an input unit 5 containing six analogue-and-bust converters (ADC) 6-11, microcomputer 12, dis

with tO 15 20

25

04404

play 13, the block diagram also shows the linear reactors 14-16 and switches 17-19 in each Laza transmission line.

The method is implemented as follows.

In the event of a short-circuit program starting body, analyzing the current level values of the phase currents, obtained by means of an input unit 5, to the inputs of which the outputs of voltage and current transformers 1-4 are connected, writes 12 codes corresponding to the integral value m values of phase currents and voltages. These values are recorded in the RAM of the microcomputer 12 at an interval that turns off the damaged mode (Lazy and its activation mode by the OAPV device that is equipped with a controlled line. Then, by the values of the phase currents and voltages in the activation mode of the damaged phase from the opposite end of the line until switching it on from the control side, determine the parameters of the systemic end of the line by

 ..fijSLLHsi H JLsi2L, I.ouL

2o (g) but (g)

+ Ј o (4) 1-0 (2)

Gde A „(g),.)

c o (g)

5o (a)

0

five

about (g) At about (g-)

0

the coefficients describing the parameters of the power line uak multipolar; current and voltage components are zero

(inverse) sequences determined by the Phase currents and voltages measured at the test site when the line from its opposite horse is switched on in the OAPV cycle. After that, the distance to the short-circuit point is calculated for currents and voltages measured at the moment of short-circuit taking into account the actual current value of the system parameters from the opposite end of the line.

Thus, the proposed method allows to increase the accuracy of determining the distance to the damage site with an unstable short circuit on lines equipped with an OAPO device, due to the determination of the current values of the system parameters from the opposite horse, which increases the reliability of the transmission line, and thereby decreases loss of power due to a more rapid search for unstable damage.

Claims (1)

Invention Formula The method of one-sided determination of the distance to an unstable single-phase short circuit on a power line with a single-phase automatic reclosing, according to which the short-circuit mode of the current and voltage is measured, is determined by The resistance of the short-circuit loop and the base angle, characterized in that, in order to improve the accuracy of determining the distance, phase and current currents are measured after successful single-phase automatic re-activation of the damaged one (Laz from the opposite end of the line before it turns on , determine the resistance of the zero and inverse sequences of the supply system from the opposite end lines, and the distance to the point of unstable single-phase short circuit is calculated taking into account the current value of the resistance of the system from the opposite horse. | 6 7 | at // 12 LA 13 Faa / 1/90 (2) lot) & 0№) Ј0 (2) osh to Xpom C№) o (2) I .2 Z & 2K2 + P p0tfj MJW№}