JP2591119B2 - Line fault location measurement method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of measuring a line fault position when a short circuit fault occurs in a line to which a repeater or the like is connected.

[Prior Art] Conventionally, as a method of measuring a line fault position, a minimum current measuring method using a power supply circuit characteristic in a repeater connected to a line is known. In this measurement method, a constant small current is supplied to the line from the feeder circuit of the repeater, and the characteristic between the line feed voltage to the line and the line resistance of the line at this time shows the nonlinearity. Then, the line pressure to the point of failure is determined by measuring the power supply voltage, and the distance to the point of failure is calculated from the line resistance value.

[Problems to be solved by the invention]

However, since the measurement of the line fault location based on the conventional microcurrent measurement method uses the characteristics of the feeder circuit of the repeater, the exact location of the line short-circuit fault from the stations at both ends of the line including the repeater is required. Cannot be measured, for example, nth repeater and n + 1
It was only possible to measure that there was a short circuit fault between the second repeater.

Also, for the above measurement, the microcurrent characteristics of the line system must be measured in advance.

[Means for solving the problem]

In order to solve such a problem, the line fault position measuring method according to the present invention employs a method in which two terminal stations related to a faulty line alternately supply a constant current to the faulty line in a direction opposite to the original power supply direction. Power supply means for supplying the power supply, the current values supplied to the faulty line by the power supply means are set to be equal to each other, and the feed voltage of the power supply means is read and measured.

[Action]

In the event of a line failure, first read the value of the power supply pressure when a constant current in the opposite direction to the original power supply direction is supplied to the failed line from one terminal station involved in the failed line. The power supply pressure when the constant current equal to the above constant current value in the opposite direction to the original power supply direction is supplied from the other terminal station to the faulty line is also read.

In this way, by obtaining the potential difference between the two end stations related to the faulty line, the constant current value, the known line resistance value of the line between the both end stations, and the resistance value per unit length of the line are known. Measure the distance from the end stations related to the failed line to the point of failure.

〔Example〕

Next, the present invention will be described with reference to the drawings. First
FIG. 2 is a circuit diagram showing a circuit fault position measuring method according to one embodiment of the present invention, and FIG. 2 is an equivalent circuit diagram when a short circuit fault occurs in a line including a repeater.

First, FIG. 2 will be described. In the figure, reference numeral 1 denotes a constant current feeder of one terminal station (hereinafter, referred to as A station) related to a line failure, 10 denotes a constant current feeder of the other terminal station (hereinafter, referred to as B station) related to a line failure, and 3 denotes a constant current feeder. Ground, a is a connection point between the + terminal of the constant current power supply unit of the A station and the faulty line, b is a connection point between the-terminal of the constant current power supply unit of the B station and the faulty line, c is a short-circuit fault point, and n ₁ · ^ReP, R ₁ is line resistance of the repeater number and line respectively within a~c interval, n ₂ · ^ReP, R ₂ is line resistance of the repeater number and line respectively within b~c interval, R _s is shorted The resistance, I, is a power supply flow based on the original power supply direction.

In the equivalent circuit diagram configured as described above, a constant current (hereinafter, referred to as a reverse constant current) which is in the opposite direction to the direction of the supply current of the stations A and B for measuring the fault position is applied to the fault line. Supply, and increase the value of this reverse constant current compared to the conventional microcurrent measurement method (about 10 times the value of the conventional)
Then, the voltage drop of the repeater becomes a negligible value because it is the forward direction of the Zener diode constituting the feeder circuit in the repeater, and can be expressed as a circuit without the repeater as shown in FIG.

Next, a circuit diagram showing a method of measuring a line fault position according to an embodiment of the present invention shown in FIG. 1 will be described. In the figure, the same parts as those in FIG. 2 are denoted by the same reference numerals, and the description thereof will be omitted. Hereinafter, the parts different from FIG. 2 will be described.
2,20 The switch for switching to B station or A station supplies the reverse constant current alternately respectively failed line, I ₁ is mutually be supplied to the failed line alternately from the A station and B station It is a reverse constant current having the same value and the opposite direction.

Next, FIG. 1 will be described in more detail using a simple mathematical formula. First, the reverse constant current is supplied from the constant current feeder 1 of the station A.
When feeding the I _1, the voltage Va of a point is represented by _{Va = (R 1 + Rs)} · I 1 ...... (1). At this time, the switch 20 is opened so that power is not supplied from the constant current supply unit 10 of the station B to the faulty line.

Similarly, the same reverse constant current I _{1 is} supplied from the constant current feeder 10 of the station B.
When power is supplied at the point b, the voltage Vb at the point _b is expressed as Vb = (R ₂ + Rs) · I ₁ (2), and the difference between the equations (1) and (2) is calculated. Holds. If the line resistance in the section a and b is α, R ₁ + R ₂ = α (4) From the equations (3) and (4), If the resistance per unit length of the line is R ₀ (Ω / Km), A
Distance L _ae from station and B station until the line fault location, L _bc each Becomes

As is apparent from the equations (7) and (8), the distance from the stations A and B to the point of the short circuit fault can be determined by measuring the potential difference between the stations A and B, respectively. R ₀ , a
Regardless short circuit resistance from line resistance α and Gyakujo current I ₁ Tokyo between ~b be easily and accurately determined.

The short-circuit resistance is obtained by substituting equation (5) into equation (1) or substituting equation (6) into equation (2).

〔The invention's effect〕

As is apparent from the above description, the line fault position measuring method of the present invention is based on the short-circuit faulty line. Since the flow is alternately applied to measure the potential difference between the two end stations and measure the position of the fault, there is an excellent effect that the configuration is simple and accurate measurement can be performed.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of a system for measuring a line fault position according to the present invention, and FIG. 2 is an equivalent circuit diagram when a short circuit fault occurs in a line in an original power supply state. 1,10 ...... constant current power supply unit, 2,20 ...... switch, 3 ...... ground, R _1, R ₂ ...... line resistance, R _s ...... short circuit resistance, I ₁ ...... reverse constant current.

Claims (1)

(57) [Claims] 1. A line fault position measuring method when a fault occurs in a line to which a repeater or the like is connected. In each of the terminal stations to which the line is connected, each terminal station alternately reverses the direction of the original power supply to the line. A power supply unit for supplying a constant current in a direction, a current value supplied to the line from the power supply unit is set to be equal to each other, and a power supply voltage of the power supply unit is read and measured. Line fault location measurement method.