JPS6385376A - Transmission line accident section detection sensor - Google Patents

Abstract

PURPOSE:To adapt a sensor to a wide current range without making the sensor large-sized, by forming a non-magnetic body part to the core part of a transformer so as to cut off the continuity of the core part being a magnetic body. CONSTITUTION:Non-magnetic body parts 3a, 3b, 3c are formed to a core part 2 being a magnetic body so as to cut off the continuity of the core part 2 and a winding part 5 for generating a secondary current is also mounted to the core part 2. In mounting the winding part 5, a fixing band 8 is detached to separate a core part 1 and the core part 2 and, after an optical fiber composite overhead ground wire (OPGW)6 is passed, the core parts 1, 2 are again joined with each other and both ends of the fixing band 8 are tightened by a tightening part 7 to complete mounting. The detection signal of each sensor is connected to OPGW6 in a joint box and sent to terminal devices arranged at a predetermined interval to discriminate an accident section which is, in turn, transmitted to a manned part such as a substation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an accident section detection sensor used for locating an accident section of an overhead power transmission line or the like.

[Conventional technology] Conventionally, in order to detect the point on a power transmission line where an accident such as a lightning strike has occurred, the surge current generated due to the accident is detected at substations, etc. located at both ends of the transmission line, and the difference in propagation time is used to detect the accident. Detects the point where this occurred. However, this method has the problem that accurate detection becomes difficult when the power system becomes complicated and a large number of branch lines are provided in the power transmission line. In order to solve this problem, an accident section detection system using optical fiber composite overhead ground wires (hereinafter referred to as 0PGW) has recently been developed. In this system, sensors are installed at 0PGW separated by a predetermined interval, and the detection signals from each sensor are connected to the 0PGW optical fiber in a joint box and collected at terminal devices installed at predetermined intervals to prevent accidents. The section is determined, and the determination result is transmitted to a manned location such as a substation using another optical fiber.

In such a fault section detection system using 0PGW, a sensor for detecting fault current is attached to 0PGW, but it is desirable that this sensor has a wide current range depending on the power transmission capacity of the power system. . For example, a current range of about 2 to 100 A is sufficient for a low voltage system of 66 KV, but a current range of several tens of OA or more is required for an ultra-high voltage system of 220 KV or higher.

As a sensor, one equipped with a current transformer (hereinafter abbreviated as CT) is generally used.

[Problems to be solved by the invention] A magnetic material such as magnetic steel or ferrite is used in the core of such a CT, but the current flowing through 0 PGW causes the core to reach a magnetic saturation point depending on the material. exists. In order to apply the sensor to a wide current range, it is necessary to increase the primary current as much as possible until the magnetic saturation point is reached.

However, if you simply increase the cross-sectional area of the core to increase the primary current until it reaches the magnetic saturation point, the core will become larger, resulting in an increase in the size of the entire sensor and a corresponding increase in weight. . For this reason, a problem arose in that it became difficult to attach to the 0PGW. Furthermore, there is a problem in that when such a large sensor is attached to an OPCW, it may damage the power transmission line.

Therefore, an object of the present invention is to provide a sensor for detecting a fault section of a power transmission line that can be applied to a wide current range without increasing the size of the sensor.

[Means for Solving the Problems] In the power transmission line accident section detection sensor of the present invention, a non-magnetic part is formed in the core part of the CT so as to break the continuity of the magnetic core part.

[Function] FIG. 3 is a diagram showing the relationship between the primary current and the secondary current in the CT of the sensor of the present invention. For comparison, FIG. 3 also shows the relationship between the primary current and secondary current in the CT of a conventional sensor.

The core portion of the CT of a conventional sensor is one in which a magnetic material is continuously provided. In conventional sensor CTs with such a core part, the secondary current increases until the primary current reaches IO, but when the primary current exceeds IO,
The secondary current becomes saturated at ■. On the other hand, in the CT of the sensor of the present invention, the primary current is 1. bigger I
The secondary current increases without being saturated until it reaches 'o.

In this manner, the CT of the sensor of the present invention reaches its magnetic saturation point at a primary current value higher than that of the conventional sensor, so it can be applied to a wide current range.

[Embodiment] FIG. 1 is a front view showing an embodiment of the present invention. In FIG. 1, 1 and 2 each indicate a half-split core portion, and by butting core portion 1 and core portion 2 together, an annular core portion is formed. The core portion is made of a magnetic material, and magnetic steel, ferrite, or the like is generally used as the material. The core portion 2 includes non-magnetic portions 3 a , 3 b T 3 c so as to break the continuity of the magnetic core portion.
are formed respectively. The material of the non-magnetic part is not particularly limited as long as it is a non-magnetic material;
For example, Bakelite, vinyl chloride, etc. can be used. A winding portion 5 (shown by imaginary lines) is attached to the core portion 2 for generating a secondary current. The sensor CT of this embodiment is attached so that the core parts 1 and 2 are located around the 0PGW 6 shown by the imaginary line.

When installing, remove the fixing band 8, divide it into the core part 1 and the core part 2, pass the 0PGW6 through it, and then butt the core parts 1 and 2 together again and tighten both ends of the fixing band 8 with the fastening part 7. Install it.

FIG. 2 is a front view showing another embodiment of the invention.

The non-magnetic parts 4a and 4b are formed between the core part 1 and the core part 2. With such a configuration, the core portion of a conventional CT can be used as is. That is, when the core part 1 and the core part 2 are butted and combined, a non-magnetic material can be inserted between the core part 1 and the core part 2 to form a non-magnetic material part. Such a structure has the advantage of being easy to manufacture, but on the other hand, the thickness of the non-magnetic material portion changes due to force when tightening the fixing band during assembly, which poses a problem in the reliability of CT characteristics. occurs.

In the above embodiments, a tangible object has been exemplified as the non-magnetic material portion, but the non-magnetic material portion may be air, that is, a void. However, if the non-magnetic material portion is made into a void, it is not preferable in terms of reliability of CT characteristics, as in the embodiment shown in FIG.

Further, it goes without saying that the number of non-magnetic parts to be formed is not particularly limited.

[Effects of the Invention] As explained above, the accident zone detection sensor of the present invention can be applied to a wide range of primary currents without increasing the cross-sectional area of the core.

Therefore, the sensor can be widely used as a compact sensor without increasing its size.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of the present invention. FIG. 2 is a front view showing another embodiment of the invention. FIG. 3 shows 1 in CT of the present invention and the conventional sensor.
It is a figure showing the relationship between a secondary current and a secondary current. In the figure, 1 and 2 are core parts, 3a, ab, 3c, 4a
, 4b is a non-magnetic material part, 5 is a winding part, and 6 is 0PGW. Figure 1/, 22 Core parts 3a, 3, 3°: Non-Katsuki part F: 1tta* 1; 0FGs no/'

Claims (1)

[Claims] (1) A transmission line accident section detection sensor equipped with a current transformer for detecting fault current, wherein a core part of the current transformer is made of a non-magnetic material so as to break the continuity of the magnetic core part. A sensor for detecting a fault section of a power transmission line, characterized in that a body portion is formed.