JPS628067A - Apparatus for locating troubled point - Google Patents

Abstract

PURPOSE:To facilitate the operation and maintenance of a transmission line and a troubled point locating apparatus by simple constitution, by outputting a locating result only when an accident point is within a locating section on the basis of a locating distance shorter than a predetermined line length ad the judgement of a front accident. CONSTITUTION:A troubled point locating apparatus 11 is constituted of a sampling circuit 12, an operational processing circuit 13, a display circuit 14 and an accident detection circuit 15. At first,a system accident is detected by the accident detection circuit 15 and, when trouble is generated in a power system, range finding operation is performed by the operational processing circuit 13 to judge whether said accident is a front one. In the case of the front accident of a transmission line, a line length setting value is read to be compared with the value of range finding operation and, if said value is smaller than the setting value, the accident of the transmission line in a section is judged to be outputted to a display circuit 14. By this method, the apparatus can be simplified without requiring a separate apparatus in the outside and the operation and maintenance of the transmission line and the trouble locating apparatus can be made easy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a fault point locating device, and particularly to a fault point locating device capable of locating the distance to a fault point when an accident occurs in an electric power system.

[Technical background of the invention]

BACKGROUND ART Conventionally, as a failure point locating device for a power transmission line, a pulse radar system, etc., which receives a surge generated at a fault point at both terminals of the power transmission line and measures its reflection time, has been put into practical use. However, these methods require a transmission device to connect both terminals of the power transmission line, or a blocking coil to prevent pulses from escaping to the outside.
Plus, it's not cheap at all.

However, in recent years, with the development of microcombustion systems, research has been actively conducted on methods that calculate the distance to the fault point using grid voltage and current data and locate the fault point at low cost (for example, JP-A No. 55-59349).

FIG. 9 shows a general configuration diagram of a digital failure point locating device using a microcomputer.

In FIG. 9, 1m and 1b are hexagonal converters into which each phase voltage and each phase current of the stain force system are introduced, respectively, and convert the input electrical quantity into a voltage signal of an appropriate magnitude. 2m and 2b are filters that remove harmonic components contained in the output of the input converter 11°1b.

3 is a sample hold circuit, each filter 2m+2b
Sample the output from at predetermined intervals.

4 is a gender conversion circuit to which the output from the sample hold circuit 3 is added via a multiplexer 5, and converts it into digital data. 6 is a direct memory access circuit (DMA) to which an A/D conversion circuit 40 input is added. 7 is a memory circuit, and the DMA circuit 6 F)I
The output of the v'D conversion circuit 4 is written to a predetermined address. 8
is a read-only memory (ROM) with a built-in siprogram. Reference numeral 9 denotes a central processing unit (CPU) which executes calculations for locating fault points according to a program written in ROM 8 and using voltage and current data of the electric power system written in mesori circuit 7. 10 is the output circuit.

(cpU) Based on the calculation result of step 9, the failure point location result is displayed on a glintter or rung (not shown). (CPU)9
Many studies have been conducted on the calculation method executed in
A method of determining the distance to the accident point using a linear equation as shown in Publication No. 9 has already been proposed.

However, X: distance to the accident point.

V breath: Voltage at location equipment installation point.

! l: current at the location equipment installation point, 1: difference current before and after the accident at the location equipment installation point, 2: impedance per unit length of the transmission line, Im: imaginary part *: conjugate complex number, especially JP-A-55-116278. Publications include ``method using mode voltage, mode current, and their changes before and after the accident.''

[Problems with background technology]

In general, the ninth step to improving power supply reliability is to respond to system accidents, that is, to quickly restore the accident, and the location of the accident is discovered based on the results of the fault location location.
In this case, it is desirable for the failure point locating device □ to operate (locate) only in the event of an accident within the section of the power transmission line, from the viewpoint of maintenance operation of the power transmission line and saving labor for maintenance. In addition, in the case of a two-terminal power transmission line, errors in location results increase due to differences in system configuration and line constants, etc. for accidents beyond the other end.
Since it is difficult to obtain highly reliable fault location results, it is desirable to limit location to accidents within a section. Furthermore, from the point of view of downsizing equipment and lowering costs, it is desirable to perform fault point location itself, including determination of whether the transmission line is inside or outside the section, since this eliminates the need for external equipment and interfaces with external equipment. .

However, the conventional digital fault location device described above performs location and outputs the results based on the operation of accident detection elements within the device, and this location can accurately determine whether a transmission line accident occurred within or outside the section. Instead, it outputs orientation results regardless of whether the accident is inside or outside. That is, the distance X obtained from the above-mentioned equation (1) can take various values depending on the magnitude and phase of the current and voltage.

Furthermore, the internal/external determination process needs to be as simple as possible (with a small number of processes) and highly reliable.

[Purpose of the invention]

The present invention was made to solve the above-mentioned problems, and it is possible to operate power transmission lines and fault point locating equipment by simply determining whether the location is inside or outside the location section and outputting the location result only when the location is within the section. The object of the present invention is to provide an entire failure point locating device that can be easily maintained, does not require an external device, and can simplify the device.

[Summary of the invention]

In the present invention, when performing fault point location.

The orientation calculation is started on the condition that an accident is detected, and the orientation output is derived on the condition that the detected accident point is in the forward direction and is smaller than a predetermined track length setting value. This is what I did.

[Embodiments of the invention]

Examples will be described below with reference to the drawings.

FIG. 1 is a functional block configuration diagram of an embodiment of a failure point locating device according to the present invention.

In FIG. 1, a fault location device 11 includes a sampling circuit 12. It is composed of an arithmetic processing circuit 131, a display circuit 14, and an accident detection circuit 15. and sampling circuit 12
It samples the voltage and current data from the grid, and based on this sampling data, the arithmetic processing circuit 13
performs arithmetic processing and outputs the result to the display circuit. In this case, the fault detection circuit 15 detects all faults in the power system, and locates the fault point only when a fault occurs in the power system.

FIG. 2 is a flowchart for explaining the content of arithmetic processing for locating a fault point, and FIG. 3 is a diagram showing the relationship between a fault point and fault point locating using two terminal systems A and B.

Step 21 is accident detection! This is the startup process.

That is, in this embodiment, no orientation operation is performed during normal times.

When an accident occurs in the power system, it is detected by the accident detection circuit 15 and the processing by the arithmetic processing circuit 13 is executed. Note that, for example, an undervoltage relay or the like is used for accident detection. When an accident is detected in step 21, the process moves to step 22.

Using the voltage of the system already stored in the memory circuit in the arithmetic processing circuit 13, the distance measurement calculation according to the equation (1) is executed, and the calculation result is set as fx. After that, move to Stella f23 and determine whether the calculation result X is greater than 0 or not. That is, it is determined whether or not there is a forward failure (protection direction failure). Here, if x (O, then the rear accident of the power transmission line (
Figure 3 Accident point Fi ), return to Stella 7''21 and proceed with activation due to accident detection.

do the right thing. In Stella f23, if X≧O, it is assumed that there is an accident in the front of the power transmission line (F or ps in FIG. 3), and the process moves to Stella f24. In step 24, the line length setting value 1
The process moves to t-reading step 25. □Steve 25
In , whether the calculation result X is smaller than the line length setting value or not 1
-Judge. If x ) L is greater in step 5, it is assumed that the accident is beyond the other end (fault point Fs in Figure 3) and the process returns to step 21. In step 25 x
< If A, it is assumed that the accident occurred within the section of the power transmission line (fault point F3 in Figure 3) and the process moves to step 26. In step 26, the calculation result xt is outputted to an external printer or display circuit 14.

As explained above, in this embodiment, it is possible to easily determine whether the vehicle is inside or outside the zone by using only the nine distances, and it is possible to output the orientation result only in the event of an accident within the zone.

By the way, even in highly accurate fault point location, an error of about 1 is included (1989 National Conference of the Institute of Electrical Engineers of Japan, 4989).
). Therefore, it is generally necessary to consider an error of about 2-. Here, errors at the fault point include errors in the main CT and main PT connected to the fault point locating device, and errors between values given as constants or setting values and actual system constants, etc. caused by factors other than the fault point locating device. There is an error. These errors cannot be prevented from occurring in calculations, and therefore, when it is necessary to highly accurately determine the inside and outside of the accident point, the processing according to the above-mentioned Figure 2 will have problems. be.

FIG. 4 is a flowchart showing the processing of another embodiment.

In this embodiment, this is a flowchart of processing contents that take into account errors, which are performed with high precision to determine whether an accident point is inside or outside.

In FIG. 4, the same parts as in FIG. 2 are designated by the same reference numerals, and detailed explanation will be omitted.

In step 41, it is determined whether the calculation result X is larger than a predetermined value -6). (Here, ε>0, for example, ε-2km from the above) Set x (-g, it will be considered as a rear accident on the power transmission line and return to Stella f21. Stella 7'41
If X≧-8, the process moves to step 23. In step 2'3, if x The process moves to reading step 43. In step 43, it is determined whether the calculation result X is smaller than the line length setting value t plus a predetermined size 1.
If it is g, it is assumed that the accident occurred beyond the other end of the power transmission line, and the process returns to Stella 7'21. If I≦L+1 in Stella 7”43, proceed to step 25. At step 25 x) t
If so, the process moves to step 44 and is set to Xt. At step 25, if X≦L, the signal is transferred to Stella f26 and output to x1.

In the above embodiment, the tolerance is glassed to the line length.

This is intended to prevent misorientation. Also, the distance from the own end to # rearward is regarded as z m Q, and the distance from the opposite end to - in front is regarded as It. Therefore, according to this embodiment, if the error due to failure point location is within the allowable value, the inside/outside determination can be made correctly. Nine operational x
If wm-a'bs or xwmL+gkm is desired to be displayed, steps 23, 25, 43 and 44 in FIG. 4 may be omitted. Furthermore, in FIG. 4, step 4
Fit t×α(α>1),
It goes without saying that ÷β (0<β<1), etc., is also incorrect.

FIG. 5 is a flowchart showing the processing of yet another embodiment.

In this embodiment, the permissible error of orientation is taken into account in order to prevent erroneous orientation. Portions in FIG. 5 that are the same as those in FIG. 2 are given the same reference numerals and explanations will be omitted.

In step 51, the calculation result X has a predetermined size of 6 (#>0
). At step 51
If so, it is assumed that there is an accident behind the power transmission line, and the process returns to step 21. If X≧ε in step 51, the process moves to step 24. At step 24, the line length setting value is read and the process moves to step 52.

Stella f52 determines whether the calculation result X is smaller than the line length t minus a predetermined size e. and step 52
If x')L-g, it is assumed that the accident occurred beyond the other end of the power transmission line, and the process returns to step 21). Further, in step 52, if I≦z−g, proceed to step 26;
The calculation result x'ft is output.

According to this embodiment, if the error in failure point location is within the allowable value, it is possible to correctly perform inside/outside determination while taking prevention of erroneous orientation into consideration.

FIG. 6 is a flowchart showing the processing of yet another embodiment, and FIG. 7 is a characteristic diagram of the directional relay element used in this embodiment.

In this example, direction reading is performed to determine the direction of the accident.
This is an attempt to use Ray. In Figure 6, the second
Components that are the same as those in the figures are given the same reference numerals and explanations will be omitted.

In step 61, the direction of the accident is detected by directional relay element processing. In the case of this process, for example, the general formula % formula % (2) for direction determination can be used.

However, V: voltage.

! : Current ψ: Angle formed by electric voltage and color current I ψ0: maximum maximum angle After the processing in step 61, the process moves to Stella f62.

In Stella f62, it is determined whether the above-mentioned direction relay element operates. That is, when the above-mentioned formula (2) is established, it is assumed that there is an accident in the front of the power transmission line, and the process moves to step 22. If the directional relay element is not activated in step 62, that is, the equation (2) does not hold, it is assumed that there is an accident at the rear of the power transmission line, and the process returns to step 21. The steps after step 22 are the same as each step in FIG.

According to this embodiment, it is possible to easily determine a rear accident, and
The outside determination process can be simplified (because equation (2) is easier to process than equation (1)).

Further, after the above description, it is clear that the processing in FIG. 4 to FIG. 6 may be combined.

Furthermore, in the middle of distance measurement calculation, that is, before calculating the value of distance X, only the polarity of distance Then, the calculation result X and the line length may be compared.

The above explanation was about a two-terminal power transmission line.

The present invention can also be easily applied to three-terminal power transmission lines.

FIG. 8 is an explanatory diagram when locating a fault point on a three-terminal power transmission line. In FIG. 8, A.

B and C indicate the names of each terminal, and terminal A is equipped with a failure point locating device 30.
will be installed. It is assumed that the distance between the failure point locating device 30 and the branch point is '2tm.

In this case, the fault points F4 and Fs are accidents located beyond the branching point as seen from the terminal personnel, and therefore, the error in locating the fault point will increase due to the influence of the branching. Therefore, it is difficult to obtain highly reliable fault point location, so it is considered appropriate to limit location to accidents within branch points. Therefore, in the case of a 3-terminal power transmission line, the "line length t" part in steps 24 and 25 of the processing contents (Figure 2) for the above-mentioned 2-terminal power transmission line is changed to "distance to branch point @ 1 m ”, and the other configurations and other processes may be the same.

In addition, in the above explanation, the line length or the distance to the branch point is treated as the line length setting value, but these may be input from the outside via an input circuit, or they may be set as constants to the memory in the arithmetic processing circuit. It may be stored in advance as . It is clear that if the constants are stored in the memory circuit, the input circuit can be omitted and the device can be simplified.

Furthermore, in this embodiment, the principle equation for locating the fault point is explained as the formula 'Ik (1), but it is not limited to this, as long as it is proportional to the distance to the fault point.

Of course, there is nothing wrong with that.

Further, in the above embodiment, the distance measurement calculation is executed after the accident detection, but the present invention is not limited to this. For example, steps 22, 23 and 24t in FIG.
It may also be output as the Xt-final result.

〔Effect of the invention〕

As explained above, according to the present invention, when locating a failure point,
The configuration is configured so that the orientation distance is smaller than a predetermined track length and forward accident determination, and the orientation result is output only when the accident point is within the orientation area. The operation and maintenance of point locating equipment can be made easier,
It is possible to provide a failure point locating device that does not require an external separate device and can be simplified.

[Brief explanation of drawings]

FIG. 1 is a functional block diagram of an embodiment of a failure point locating device according to the present invention, and FIG. 2 is a flowchart illustrating the contents of arithmetic processing for locating a failure point. FIG. 3 is a system diagram showing the relationship between fault points and fault point location, FIG. 4 is a flowchart showing the processing of another embodiment, and FIG.
FIG. 6 is a flowchart showing the processing of still another embodiment.
FIG. 7 is a flowchart showing the processing of still another embodiment.
The figure is a characteristic diagram of the directional relay element used for the processing in Figure 6.
FIG. 8 is an explanatory diagram for locating a fault point on a three-terminal power transmission line, and FIG. 9 is a general configuration diagram of a digital fault locating device using a microcomputer. 1m, 1b...input converter, 2m, 2b...filter, 3...sample hold circuit. 4...■Converter, 5...Multiplexer, 6
...Direct memory access device. 7...Memory circuit, 8...ROM. 9... Central processing unit, 10... Output circuit. 11.30...Fault point locating device. 12... Sampling circuit, 13... Arithmetic processing circuit, 14... Display circuit. 15... Accident detection circuit. Figure 1 Figure 2 Figure 4 Figure 6 Figure 7

Claims (5)

[Claims] (1) Sampling the voltage and current data of the power system and converting it into digital quantities, using the data converted to digital quantities to perform predetermined calculations, calculating the distance to the fault point, and calculating the distance to the fault point. A failure point locating device that performs external determination includes a first means for detecting an accident, a second means for locating a distance to a failure point when a condition of the first means is satisfied, and a third means for determining the accident. means, fourth means for determining that the distance to the fault point detected by the second means is smaller than a predetermined line length setting value, and the third and fourth means. A failure point locating device characterized by comprising a fifth means for outputting an output from the second means as a locating result when each condition of the means is satisfied. (2) The failure point locating device according to claim 1, wherein the third means uses a directional relay element. (3) Sampling the voltage and current data of the power system and converting it into digital quantities, performing predetermined calculations using the data converted to digital quantities, calculating the distance to the fault point, and calculating the distance to the fault point. A failure point locating device that performs external determination includes a first means for detecting an accident, a second means for locating a distance to a failure point when a condition of the first means is satisfied, and a detection method using the second means. a third means for determining whether the distance to the fault point detected by the second means is greater than a predetermined positive or negative magnitude, and a distance to the fault point detected by the second means is determined in advance. a fourth means for determining that the set value of the line length is smaller than an amount corresponding to the sum of a predetermined positive or negative magnitude, and when each of the conditions of the third and fourth means is satisfied; A failure point locating device characterized by comprising a fifth means for outputting the output from the second means as a locating result. (4) The failure point locating device according to claim 1 or 2, wherein the line length setting value can be set externally via an input circuit. (5) The magnitude comparison by the fourth means is performed with any predetermined amount in which the line length setting value l and the predetermined constants α and β have the following relationship. Or the failure point locating device according to paragraph 2. l×α(α>1) l÷β(0<β<1)