JP3023366B2 - Branch line fault direction locating device - Google Patents

Description

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

2. Description of the Related Art Conventionally, as an apparatus for locating which transmission line has a fault in a branch transmission line, for example, as shown in Japanese Patent Application Laid-Open No. 61-76019, There has been proposed a light emitting diode which emits light by a current flowing through a ground wire, and which knows a failure direction from the light emitting state of these light emitting diodes.

[Problems to be Solved by the Invention] However, in the above-described conventional device, only the presence / absence of light emission corresponding to the presence / absence of a current is relied on, and the magnitude of a current that causes a remarkable change at the time of failure is not considered. However, depending on the type of failure, the orientation of the failure was not always accurate.

Further, it was only possible to determine the direction of the failure, and it was not possible to grasp the content of the failure at all.

Furthermore, since the current detecting means and the light emitting means have to be installed on all the overhead ground lines connected to the branch point, the apparatus is complicated.

Therefore, an object of the present invention is to solve the above-mentioned drawbacks of the prior art by comparing the magnitude and phase of the current flowing in the overhead ground wire, and to reliably locate the failure direction regardless of the failure content. Moreover, it is an object of the present invention to provide a branch transmission line fault direction locating device capable of knowing the details of a fault depending on the fault direction.

[Means for Solving the Problems] The present invention relates to a fault direction locating device for a branch transmission line having branch transmission lines 2 and 3 for supplying power from a power supply to a plurality of loads. The power supply side current sensor 5 for measuring the overhead ground wire currents Ia, Ib, Ic on the power supply side (a), the load side (b), and (c) respectively, and the load side current sensors 6, 7
And an orientation circuit 12 to which information of these sensors is guided. The output Ia of the power supply-side current sensor 5 is compared with a preset maximum value Iha, and if Ia ≦ Iha, an accident occurs. It is determined that an accident has not occurred or an accident has occurred on the side a far from the branch. If Ia> Iha, it is determined that an accident has occurred, and the magnitudes of the outputs Ib and Ic of the load-side current sensors 6 and 7 are determined. When Ib> Ic, it is determined that an accident has occurred in the transmission line 2 or the load b between the sensor and the load b, and when Ib <Ic,
When it is determined that an accident has occurred in the transmission line 3 or the load c between the sensor 7 and the load c, and when Ib = Ic, the accident has occurred in the transmission line 1 between the power source a and the branch tower J or the branch tower J. And a phase difference φb (0 <= φ <180) of the current Ib with respect to the current Ia.
°) and the set phase value of 90 °, and if φb> 90 °, it is determined to be a ground fault at the branch tower J, and if φb ≦ 90 °, the fault between the sensor 5 and the power source a is determined. A ground fault in the transmission line 1 or a short circuit accident between the power source a and the branch tower J or in the branch tower J is determined.

[Operation] In the fault direction locating device of the present invention, when a fault occurs in the power transmission line, the current flowing through the overhead ground wire on the power supply side increases. Therefore, when the output of the power-supply-side sensor is guided to the orientation circuit and the magnitude of the output is checked, it can be determined whether or not a failure has occurred.

Further, a certain magnitude relationship is established between the currents flowing through the overhead ground wires on the load side depending on whether the failure of the transmission line is on the power supply side or on which load side, that is, on the failure direction. Therefore, when the magnitudes of the outputs of the load-side sensors are compared by the orientation circuit, it is possible to determine 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 current side, the phase of the current flowing on the overhead ground wire on the load side is different from the phase of the current flowing on the overhead ground wire on the current side depending on the type of fault such as a ground fault fault or a short-circuit fault. different. Therefore, when the phase difference between the output of the power-supply-side sensor and the output of the load-side sensor is determined by the orientation circuit and its magnitude is checked, the contents of the failure on the power-supply side can be known.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1, 2, and 3. FIG. Here, the case where there are two loads is handled, but the same applies to the case where there are three or more loads.

FIG. 1 shows an embodiment of a branch transmission line fault direction locating apparatus 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 transmission line on the load b side, 3 is a transmission line on the load c side, and 4 is an overhead ground wire.

This device uses the a-side, b-side, and c-side overhead ground lines 4 near the branch point.
Current sensors 5, 6, 7 for measuring overhead ground wire currents Ia, Ib, Ic on each side, and a locating circuit 1 from which information of these sensors is derived.
And two. The orientation circuit 12 compares the magnitude of Ia with a preset normal maximum value Iha.
And a comparison circuit 9 for comparing the magnitude of Ib with the magnitude of Ic
And a phase comparison circuit 10 for comparing the phase of Ia with the phase of Ib,
It is composed of an orientation calculation circuit 11 from which these circuit outputs are derived.

The current sensors 5, 6, 7 are, for example, current transformers, orientation circuits 1
Each of the circuits 8 to 11 constituting 2 is configured using a linear IC or a microcomputer. An optical fiber is preferably used for the transmission path from the current sensors 5, 6, 7 to the orientation circuit 12 for lightning resistance.

Next, the function of the orientation circuit 12 will be described with reference to FIG.

The output Ia of the sensor 5 and a preset normal maximum value Ih
is compared with a in the accident detection circuit 8, and when Ia ≦ Iha, it is determined that no accident has occurred or that an accident has occurred on the a side far from the branch. When Ia> Iha, it is determined that an accident has occurred, and the magnitude of Ib and the magnitude of Ic are compared by the comparison circuit 9. When Ib> Ic, power transmission between the sensor b and the load b is performed. It is determined that an accident has occurred on the line 2 or the load b, and when Ib <Ic, the c side, that is, the load c
It is determined that an accident has occurred in the transmission line 3 or the load c during. If Ib = Ic, it is determined that an accident has occurred on the a side, that is, on the transmission line 1 between the power source a and the branch tower J or on the branch tower J, and the phase difference of the current Ib with respect to the current Ia is further determined. φb (0 <= φb <180 °) and the set phase value of 90 °
Are compared by the phase comparison circuit 10, and when φb> 90 °, a ground fault at the branch tower J is determined, and when φb ≦ 90 °, the transmission line 1 between the sensor 5 and the power source a is determined. And a short circuit accident between the power source a and the branch tower J or at the branch tower J.

Here, Ib = Ic is not strict, and if the difference between them is within a range of about 30%, it is assumed that Ib = Ic.

The principle of this device will be described with reference to FIG. 3 together with the current state of the overhead ground wire 4 near the branch point at the time of the accident.

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

In addition, when the a-side ground fault accident occurs, the phase difference φb of Ib with respect to Ia is almost the same as that of the a-side ground fault accident. The fact that φb becomes almost 180 ° when a ground fault accident occurs in the above case is utilized.

According to the above-described embodiment, since the details of the failure on the power supply side, which is more important than the load side, can be particularly grasped, the merit is great.

In addition, by combining a conventionally used locating device for finding a line length from a measurement point to a fault point with the present device for finding a fault direction, it is possible to further increase the locating reliability.

In the above embodiment, the load-side input to the phase comparison circuit 10 is obtained from the sensor 6 on the load b side. However, the absolute value φc of the phase difference between Ia and Ic obtained from the sensor 7 on the load c side is φb.
May be used instead. In particular, if the orientation calculation circuit 11 confirms whether or not the comparison result is the same using both the phase differences φb and φc, the reliability of the orientation regarding the failure content can be increased.

The orientation result obtained from the orientation 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.

[Effects of the Invention] The branch transmission line fault direction locating device of the present invention detects an overhead ground wire current which causes a remarkable change at the time of a failure by a current sensor and guides the current to an orientation circuit. Since different current magnitudes are analyzed, the direction of the fault can be accurately located regardless of the type of fault. Further, not only the magnitude of the current but also the phase is analyzed, so that when a failure occurs on the power supply side, the contents can be known.

[Brief description of the drawings]

FIG. 1 is a block diagram of a transmission line fault direction locating device showing an embodiment of the present invention, FIG. 2 is a diagram for explaining the functions of the circuit shown in FIG. 1, and FIG. 3 is a characteristic diagram of an overhead ground wire current at the accident site. It is. In the figure, 1 is a transmission line on a power source a side, 2 is a transmission line on a load b side, 3 is a transmission line on a load c side, 4 is an overhead ground wire, 5 is a current sensor on the a side, and 6 is a current sensor on the load b side. Current sensor, 7 is load c
The current sensor on the side, 12 and 22 are orientation circuits, a is a power supply, b and c are loads, and J is a branch tower.

Claims (1)

(57) [Claims] 1. An apparatus for locating a fault direction of a branch transmission line having branch transmission lines 2 and 3 for supplying power from a power source to a plurality of loads, comprising: an overhead ground wire 4 near a branch point; In each of (b) and (c), the power source side current sensor 5 and the load side current sensors 6, 7 for measuring the overhead ground wire currents Ia, Ib, Ic, respectively.
And an orientation circuit 12 to which information of these sensors is guided. The output Ia of the power supply-side current sensor 5 is compared with a preset maximum value Iha, and if Ia ≦ Iha, an accident occurs. It is determined that an accident has not occurred or an accident has occurred on the side a far from the branch. If Ia> Iha, it is determined that an accident has occurred, and the magnitudes of the outputs Ib and Ic of the load-side current sensors 6 and 7 are determined. When Ib> Ic, it is determined that an accident has occurred in the transmission line 2 between the sensor and the load b or in the load b. When Ib <Ic, the transmission line 3 or the sensor between the sensor 7 and the load c When it is determined that an accident has occurred at the load c and Ib = Ic, it is determined that an accident has occurred at the transmission line 1 between the power source a and the branch tower J or the branch tower J, and the current Ib with respect to the current Ia is determined. Phase difference φb (0 <= φb <180
°) and the set phase value of 90 °, and if φb> 90 °, it is determined to be a ground fault at the branch tower J, and if φb ≦ 90 °, the fault between the sensor 5 and the power source a is determined. A branch transmission line fault direction locating device for locating a ground fault in the transmission line 1 or a short circuit accident between a power source a and a branch tower J or a branch tower J.