JPS60263869A - Detecting device for accident point on power transmission line - Google Patents

Abstract

PURPOSE:To detect accurately the position of an accident point at every steel tower or its span, etc., by providing a current transformer which uses the constituent frame body of the steel tower as a primary conductor to part of the steel tower. CONSTITUTION:The current transformer 2 which uses the constituent frame body of the steel tower as the primary conductor is provided to some part of the constituent frame body at two vertically distant positions, and a comparator 5 which detects whether the level of a secondary current exceeds a set limit or not is connected to the secondary side of each current transformer 2. Then, the current transformer 2, comparator 5, a light emitting device 6, a photodetection part 7, etc., constitute a detection part 9. The detection part 9 is connected to a terminal station of the power transmission line, a position decision device 12 decides on the position of a ground fault, interphase ground fault, etc., through a photoelectric converter 11, and the result is displayed on a display part 13. If an accident occurs, on the other hand, the discharging current of a lightening stroke flows the structure of a steel tower nearby the ground fault accident point. Then, it is acquired by a current transformer 2 provide to the steel tower and the detection part 9 outputs an abnormality signal, thereby detecting the occurrence of the accident.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a device for detecting a fault point on a power transmission line based on a current flowing through a frame of a steel tower.

"Prior Art" Conventionally, when an electrical fault such as a ground fault or correlated short circuit occurs on a part of a power transmission line, the search for the fault point has been carried out manually. For this reason, in the case of power transmission lines installed in mountainous areas, remote areas, etc. with severe natural conditions, there is a problem in that finding and confirming fault points is difficult and requires a great deal of effort and time.

``Object of the Invention'' The present invention advantageously solves the above-mentioned problems, and can accurately detect the location of the accident point on each tower or its span, and is easy to install and highly practical. A point detection device is provided.

"Structure of the Invention" In order to achieve the above-mentioned object, the present invention provides a current transformer in which a part of a steel tower has its constituent frame as a primary conductor, and detects abnormal current in the transmission line at the time of a line fault. It is characterized by this.

"Embodiment" Hereinafter, an embodiment of the present invention will be described based on FIG. 1 and FIG. 2.
1c, a flow transformer path 2 using this as a -order conductor is arranged vertically such that one is above the upper phase arm 3 and the other is below the lower phase arm 4. A comparator 5 is provided at two separate locations, and the secondary of the current transformer 2 is provided with a comparator 5, as shown in FIG. is connected to the comparator 5, and this comparator 5 is equipped with simultaneous protection means such as a surge absorber, output means for keeping the level of the output signal constant, etc., and a light emitter 6 such as a light emitting diode is connected to this output section. At the same time, the emitted light is guided by the light receiving section 7 to the optical fiber 8, and the current transformers 2. Comparator 52 Emitter 6. The light receiving section 7 and the like constitute a detection section 9 for each steel tower IA, IB, and 10. Further, each detection section 9 is connected to both end stations of the power transmission line along the power transmission line through an optical fiber or the like built into the overhead ground wire 10, and is connected to both end stations of the power transmission line at the end stations.

Information for each detection unit 9 is processed by a position determiner (for example, a central processing unit) 12 via a photo/electrical converter 11, and the display unit 1 indicates at which position an abnormality such as a ground fault or a short circuit between phases has occurred.
This is known from 3.

Next, we will discuss the current flowing through the current transformer 2 in the normal state and when an accident occurs.

Considering the state in which normal load current is flowing through each phase wire U, V, and W, each current transformer 2 is installed at the wire U as shown in FIG.

The current flowing through the frame of the tower 1, which is the primary conductor of the current transformer 2 because it is away from W, is
This is mainly the circulating current i generated by the intersection of the magnetic flux generated around the electric wire U or W by the load current and the component frame. Therefore, the setting limit of the secondary current of the current transformer 2 is set to, for example, 10% of the rated current of the power transmission line.
The circulating current i generated by the double overcurrent is determined as the secondary current value at this time, and when this set limit is exceeded, a signal is output from the comparator 5 and the first light emitter 7 is activated. This is done so that no signal (light) is output from the detection unit 9 within the normal load current range.

On the other hand, considering the situation where a ground fault has occurred, for example,
As shown by the solid line in the diagram, if a lightning strike is applied to the overhead ground [10] located near the steel tower IB, most of the electrical discharge during the lightning strike will flow through the structural frame of the steel tower IB near the ground fault point x4. A part of the discharge current at this time, when flowing through the component frame which is the primary conductor of the current transformer 2, has a short flow time and contains a DC component, but the absolute value of the current is smaller than the circulating current 5. becomes extremely large. Therefore, the occurrence of a ground fault is detected by the current transformers 2 provided at the upper and lower positions of the steel tower IB, and the captured current value surely exceeds the set limit.

Two abnormality occurrence signals are output from the detection unit 9 of the steel tower IB,
The occurrence of a ground fault is detected on the condition that both the upper and lower signals are output. Furthermore, depending on the location of the ground fault point When an abnormality occurrence signal is sent from the section 9 to the position determination device 12, it is determined that the ground fault point X is located at an intermediate position between the plurality of detection sections 9, and a display is made.

Next, considering the situation in which a correlated short circuit fault occurs, if a ground fault fault occurs at the same time as a correlated short circuit fault, a portion of the ground fault current can be captured by the current transformer 2 located below. The short circuit fault point Y can be detected based on the occurrence of a single ground fault fault. Furthermore, considering the case of a correlated short-circuit accident that does not involve a ground fault, if a correlated short-circuit accident occurs between electric wire U and electric wire V located between towers IB and IC, as shown by the chain line in Figure 1, If the power supply side is to the left of the short-circuit point Y, a short-circuit current of, for example, several tens of times the rated current flows through the electric wires U and V located to the left of the short-circuit point Y. Since the magnetic flux generated by this short-circuit current intersects with the component frame, the circulating current is captured by the current transformer 2 located above. Since the circulating current at the time of a short circuit exceeds the set limit mentioned above, an abnormality occurrence signal is output from each detection section 9 located to the left of the short circuit fault point Y, and an abnormality signal is output from each detection section 9 located to the left of the short circuit fault point Y. No signal will be output from the located detection section 9. Based on these results, the position of the short-circuit fault point Y can be determined by creating a boundary between the presence and absence of an abnormality occurrence signal in each detection unit 9 and by outputting an abnormality occurrence signal from only one of the upper and lower current transformers 2. Steel tower IB, 10
It is possible to detect the distance between the two.

In the examples of FIGS. 1 and 2, the secondary current of the current transformer 2 is used as a drive source for the comparator 5 and the light emitter 6, and outputs an optical signal without using an auxiliary power source such as a battery. It is supposed to be done.

Further, it is preferable that the current transformer 2 be of a split-core type or the like, which can be installed without dismantling the tower-constituting frame.

In addition, in the example of FIG. 1 and FIG. 2, the detection unit 9 is installed for each steel tower.
In addition to installing a force detection unit 9 that detects both ground faults and phase-to-phase short circuits, it is necessary to install force detection units 9 at every few towers, or to install a current transformer specifically for ground faults or phase-to-phase short circuits. You can also do that. In addition, if the current transformer is used only for ground fault detection, it can be installed at any one location on the tower component frame.On the other hand, if the main purpose is to detect correlated short circuits, the current transformer can be installed at any one location on the tower component frame. It may also be located near each phase electric wire.

"Effects of the Invention" As explained above, according to the present invention, the following effects can be achieved.

■ Ground faults and correlated short circuit fault points can be detected with high precision for each tower by the detection unit, and the location of the fault point can be known at the same time as an accident occurs at a power transmission line terminal station, etc.

■ Therefore, regardless of the area where the power transmission line is installed, it is possible to easily check whether an accident has occurred at any time, and the labor involved in maintaining the line can be significantly reduced.

■ It is highly practical as it allows easy work such as attaching the current transformer to the steel tower frame and can be easily applied to existing power transmission lines.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a schematic diagram of a power transmission line showing current transformer mounting positions and fault points, etc., and FIG. 2 is an explanatory diagram of the configuration of the device. IA, IB, IC... Steel tower, 2... Current transformer, 9... Detection section. Applicant Fujikura Electric Wire Co., Ltd.

Claims (1)

[Claims] A fault point detection device for a power transmission line, which is equipped with a current transformer (2) on a part of a transmission line tower (CIA, IB, IC) that detects the current flowing through the tower using its component frame as a primary conductor.