JPH01255434A - Device for determination of branched transmission line trouble direction - Google Patents

Abstract

PURPOSE:To effectively determine a trouble direction irrespective of the content of a trouble by detecting an aerial ground line current which is remarkably varied at the time of the trouble, and discriminating it by a determination circuit. CONSTITUTION:Currents (Ia), (Ib), (Ic) of the sides (a), (b), (c) are respectively measured by current sensors 5, 6, 7 at aerial ground line 4 near a branching point. The output Ia of the sensor 5 is compared by a trouble detector 8 with a preset maximum value Iha, a trouble is determined in case of Ia>Iha. In this case, the current Ib is compared by a comparator 9 with an Ic, it is determined that the trouble occurs at the side (b) in case of Ib>Ic, at the side (c) in case of Ic>Ib and at the side (a) in case of Ib=Ic. Further, when the phase difference phib between the currents Ia and Ib is phib>90 deg.C, a ground fault is judged at a branch iron tower J. In case of phiv<=90 deg., a ground fault is judged between the sensor 5 and a power source (a) or between the power source (a) and the tower J.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a branch power transmission line fault direction locating device that improves fault direction locating accuracy.

[Prior Art] Conventionally, in a power transmission line with branches, as a device for locating which transmission line has a failure, as shown in Japanese Patent Application Laid-Open No. 61-76019, A system has been proposed in which light emitting diodes are provided that emit light using a current flowing through a ground wire, and the direction of failure can be determined from the state of light emitted by these light emitting diodes.

[Problems to be Solved by the Invention] However, the above-mentioned conventional devices simply relied on the presence or absence of light emission corresponding to the presence or absence of current, and did not take into account the magnitude of the current that would cause a significant change in the event of a failure. Therefore, depending on the nature of the failure, it may not always be possible to determine the direction of the failure accurately.

Moreover, it was only possible to locate the direction of the failure, and it was not possible to understand the details of the failure at all.

Furthermore, since current detection means and light emitting means must be installed on all the overhead ground wires connected to the branch point, the apparatus becomes complicated.

Therefore, an object of the present invention is to overcome the above-described drawbacks of the prior art by comparing the magnitude and phase of the current flowing through the overhead ground wire, and to reliably locate the fault direction regardless of the nature of the fault. Moreover, it is an object of the present invention to provide a branch power transmission line failure direction locating device that can determine the failure details depending on the failure direction.

Another object of the present invention is to provide a branch power line failure direction locating device that can simplify the device by omitting one current sensor.

[F stage for solving the problem] The first invention is a failure direction locating device for a branch power transmission line having a branch line that supplies power from a power source to a plurality of loads. Each overhead ground wire is equipped with a current sensor for detecting the current flowing therethrough, and the outputs of these current sensors are directed to a location circuit. The location circuit is
The occurrence of a failure is determined based on the output size of the power supply side sensor among the current sensors, and the output size of the load side sensors is compared, and based on the comparison output, it is determined whether a failure has occurred on the power supply side or any load side. At the same time, the phase difference between the outputs of the power source side sensor and the load side sensor is determined, and the nature of the failure on the power source side is determined from the magnitude of the phase difference.

The second invention is a failure direction locating device for a branch power transmission line having a branch line that supplies power from a power source to a plurality of loads. The outputs of these current sensors are routed to the locating circuit.The locating circuit determines the occurrence of a failure based on the magnitude of each output of the current sensors, and also compares the magnitude of the outputs of the current sensors. Then, from the comparison output, it is determined whether the failure has occurred on the power supply side or on which load side.

: Effect 1 In the failure direction locating device of the first invention, when a failure occurs in the power transmission line, the current flowing through the overhead ground wire on the power source side increases. Therefore, when the output of the power supply side sensor is led to the locating circuit and the magnitude of the output is checked, it can be determined whether or not a failure has occurred.

Further, depending on whether the failure of the power transmission line occurs on the power supply side or on which load side, that is, depending on the direction of the failure, a certain magnitude relationship is established between the currents flowing in the overhead ground wire on the load side. Therefore, when the magnitudes of the outputs of the load-side sensors are compared in the locating circuit, it can be determined from the comparison result whether the failure has occurred on the power supply side or on which load side.

Furthermore, when a fault occurs on the power supply side, the phase of the current flowing in the overhead ground wire on the load side may differ depending on the nature of the fault, such as a ground fault or short circuit fault, compared to the phase of the current flowing in the overhead ground wire on the power supply side. different. Therefore, when the phase difference between the outputs of the power source side sensor and the load side sensor is determined by the locating circuit and its magnitude is checked, the nature of the failure on the power source side can be determined.

In the failure direction locating device of the second invention, when a failure occurs in the power transmission line, the current flowing through the overhead ground wire on the load side increases. Therefore, when the output of the load-side sensor is led to the locating circuit and the magnitude of the output is checked, the occurrence of a failure can be determined.

Further, the direction of failure is determined by the same operation as in the first invention described above.

[Example] An example of the present invention will be described below based on FIGS. 1, 2, and 3. Note that although the case where there are two loads is considered here, the same applies to cases where there are three or more loads.

FIG. 1 shows an embodiment of a branch power line fault direction locating device according to the present invention. As shown in the figure, J is a branch tower, 1 is a power transmission line on the power source a side, 2 is a power transmission line on the load side, 3 is a power transmission line on the load C side, and ll is an overhead ground wire.

This device measures the overhead ground wire current on each of the a side, b side, and a side of the overhead ground wire 4 near the branch point! a, Ib.

It includes current sensors 5, 6.7 that measure Ic, and a location circuit 12 from which information from these sensors is derived. The location circuit 12 includes an accident detection circuit 8 that compares the magnitude of Ia and a preset normal maximum value Iha, a comparison circuit 9 that compares the magnitude of Ib with the magnitude of Ic, and a circuit that compares the magnitude of Ia with the magnitude of Ib. It is composed of a phase comparator circuit 10 that compares phases, and a location calculation circuit 11 to which the outputs of these circuits are derived.

The current sensors 5, 6.7 are constructed using, for example, a current transformer, and each of the circuits 8 to 11 constituting the location circuit 12 is constructed using a linear IC or a microcomputer. Current sensor 5
, 6.7 to the location circuit 12, it is preferable to use an optical fiber for lightning resistance.

Next, the function of the location circuit 12 will be explained based on FIG.

Output Ia of sensor 5 and preset normal maximum value I
ha is compared with the accident detection circuit 8, and when Ia≦Iha, it is determined that an accident has not occurred or that an accident has not occurred on the side a, which is far from the branch.

When Ia>Iha, it is determined that an accident has occurred, and I
A comparison circuit compares the magnitude of b and the magnitude of Ic, and Ib
> In the case of Ic, it is determined that the fault has occurred on side b, that is, on the power transmission line 2 between the sensor and the load, or on the load, and
If b < I c, it is determined that the accident occurred on the a side, that is, on the power transmission line 3 between the sensor 7 and the load C or on the load C. And in the case of Ib-Ic, the a side, that is,
It is determined that an accident has occurred on the power transmission line 1 between the power supply a and the branch tower J or on the branch tower J, and the phase difference φb (0<=φ×180°) between the current Ib and the current 1a is set. The phase comparison circuit 10 compares the value with 90°,
If φb>90°, it is determined that there is a ground fault at the branch tower J, and if φb≦90°, it is determined that there is a ground fault in the power transmission line 1 between the sensor 5 and the power source a, or a ground fault occurs between the power source a and the branch tower J. This is determined to be a short-circuit accident between J and branch tower J or branch tower J.

Note that Ib-Ic here is not strict, and if the difference between the two is within a range of about 30%, it is defined as Ib-Ic. Furthermore, φb〉90° and φb≦90° are not limited to 90°, but φb>120" and φb, respectively.
It may also be approximately b<60''.

The principle of this device will be explained based on FIG. 3, together with the current state of the overhead ground wire 4 near the branch point at the time of an accident.

First, regarding the detection of the occurrence of an accident, when an accident occurs on the power transmission line, Ia is always larger than the maximum value Iha in normal times, except in the vicinity of the power supply a side. Next, regarding the orientation of the accident direction, looking at Ib and Ic, in an accident on the a side or a branch tower, Ib - Ic, in an accident on the b side Ib > Ic, and in an accident on the a side Ib<Ic.

In addition, when determining whether a ground fault occurs on the a side or a branch tower, if a ground fault occurs on the a side, I
The phase difference φb of b is almost the same, but when a ground fault occurs in a branch tower, φb becomes approximately 180°.

According to the embodiment described above, it is possible to particularly grasp the details of the failure not on the load side but on the power supply side, which is more important, so there is a great advantage.

Furthermore, by combining a conventionally used locating device that determines the line length from a measurement point to a fault point with this device that determines the direction of a fault, it is possible to further increase the locating reliability.

In the above embodiment, the load-side input to the phase comparison circuit 10 is taken from the sensor 6 on the load side, but the absolute value φC of the phase difference between Ia and Ic is determined by φb from the sensor 7 on the load C side. It may be used instead.

In particular, if both phase differences φb and φC are used to confirm whether or not the comparison results are the same in the location calculation circuit 11, the reliability of location regarding the failure details can be increased.

Further, the location results obtained from the location circuit 12 may be sent to a central monitoring station using an optical fiber in an optical fiber composite overhead ground wire (OPGW), or may be displayed or recorded on a branch tower.

4, 5, and 6 show modified embodiments of the present invention. The main difference between FIG. 4 and FIG. 1 is that the current sensor is connected from the overhead ground wire 4 on side a near the branch tower. This is the point that has been removed. As a result, the location circuit 22 includes a comparison circuit 18 that compares Ib with a preset maximum value of Ib during normal times, and a comparison circuit that compares Ic with a preset maximum value Ihc of Ic during normal times. 28, a comparison circuit 19 that compares Ib and Ic, and a location calculation circuit 21 to which the outputs of these circuits are derived.

Next, the function of the orientation circuit 8322 will be explained based on FIG.

Output Ib of sensor 6 and preset maximum normal value I
hb is compared with the comparator circuit 18, and the output I of the sensor 7 is
A comparator circuit 28 compares c with a preset maximum normal value Ihc, and when Ib≦Ihb and Ic≦Ihc, it is determined whether an accident has occurred or whether an accident has occurred on side a, which is far from the branch.

When Ib>Ihb or Ic>Ihc, it is determined that an accident has occurred, and the comparison circuit 19 compares the magnitude of Ib with the magnitude of IC. If Ib>Ic, it is determined that no accident has occurred on the b side. If Ib<Ic, it is determined that the accident occurred on side a, and if Ib=Ic, aff! ! l Determine that the accident occurred on a power transmission line or branch tower.

The locating principle of this device will be explained based on FIG. 6, together with the current state of the overhead ground wire near the branch point at the time of an accident.

First, regarding the detection of the occurrence of an accident, if an accident occurs, at least one of Ib and Ic will be larger than the normal maximum value unless the accident occurs at a point far from the branch point on the a side.

Next, regarding the orientation of the accident direction, in the case of an accident at the branch tower on the a side, Ib=Ic, in the case of an accident on the b side, Ib>Ic, and in the case of a cfFI accident, Ib<Ic.

The above is the principle of the orientation method.

According to the above-mentioned modification, if a failure does not occur on the power supply side, although the details of the failure cannot be known, the current sensor only needs to be installed on the load side, and only one sensor on the power supply side can be installed.
Since these parts can be omitted, the apparatus can be simplified.

[Effects of the Invention] Since the present invention is configured as described above, it provides the following effects.

In the branch power transmission line fault direction locating device according to claim 1, the overhead ground wire current, which changes significantly at the time of a fault, is detected by a current sensor and guided to a locating circuit, and this locating circuit detects a current that differs depending on the direction in which the fault occurs. Since the magnitude of the error is analyzed, the failure direction can be accurately located regardless of the failure details. In addition, since not only the magnitude of the current but also the phase is analyzed, the content of the failure can be known in the event of a failure on the power supply side. Although this is not possible, it is possible to simplify the device by omitting one current sensor on the power supply side while ensuring accurate location of the fault direction.

4. Diagrams) Brief Description FIG. 1 is a configuration diagram of a power transmission line failure direction/direction locating device showing an embodiment of the present invention, and FIG. 2 is a functional explanatory diagram of the circuit shown in FIG. 1.
Figure 3 is a characteristic diagram of the overhead ground wire current at the accident location.
The figure is a configuration diagram showing a modification example in which the power supply side sensor of Fig. 1 is omitted, Fig. 5 is a functional explanatory diagram of the circuit shown in Fig. 4, and Fig. 6 is a characteristic diagram of the overhead ground wire current at the accident point. .

In the figure, 1 is the power transmission line on the power source a side, 2 is the power transmission line on the load side, 3 is the power transmission line on the load C side, 1 is the overhead ground wire, 5 is a
6 is a current sensor on the load side, 7 is a current sensor on the load C side, 12.22 is a location circuit, a is a power source,
b and c are loads, and J is a branch tower.

Claims (1)

[Claims] 1. In a failure direction locating device for a branch power transmission line having a branch line that supplies power from a power source to a plurality of loads, these Install a current sensor that detects current, determine whether a failure has occurred based on the output size of the power supply side sensor among these current sensors, compare the output size of the sensors between the loads, and use the compared output to determine whether the power source In addition to determining whether a failure has occurred on either side or the load side, a locating circuit is installed that determines the phase difference between the outputs of the power supply side sensor and the load side sensor, and determines the nature of the failure on the power supply side based on the magnitude. A branch power line fault direction locating device characterized by: 2. In a fault direction locating device for a branch power transmission line that has a branch line that supplies power from a power source to multiple loads, a current sensor is installed on each overhead ground wire between the loads at the branch point to detect the current flowing through them. In addition to determining the occurrence of a failure from the magnitude of each output of the current sensor, the magnitude of the outputs of the current sensors is compared, and from the comparison output it is determined whether the failure has occurred on the power supply side or on either the load side. A branch power transmission line failure direction locating device characterized by having a locating circuit for determining.