JPH0534377A - Distribution line monitoring apparatus - Google Patents

Abstract

PURPOSE:To obtain the shape and structure of a case of a stable optical type voltage/current sensor even in raining or snowing. CONSTITUTION:In the size of a case body, a distance to the surface of the case body from the center of a distribution line 2 is set at 5.0cm or more in the direction vertical to the distribution line 2 and that more than double as compared with the length of a capacitor potential divider in the direction parallel to the distribution line 2. A protruding matter such as flange 22 is provided on the surface of the case body. Thus, a higher resistance is maintained between an arbitrary position of the surface of the case body and the distribution line 2 even when pollution occurs.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distribution line monitoring device, which is installed to monitor the operating condition of a distribution line or a transmission line having a relatively high voltage, and in particular, the zero-phase voltage of a three-phase distribution line can be simplified. This is for accurate detection.

[0002]

2. Description of the Related Art In today's society, momentary power outages are unacceptable and the situation of power transmission or distribution is constantly grasped.
It is necessary to predict the occurrence of accidents or prevent them from occurring.

In response to such a demand, conventionally, a distribution line monitoring device used for an overhead power distribution line has a zero-phase current transformer (referred to as ZCT) or a built-in relay switch installed on a utility pole. It was electrically measured and monitored by a zero-phase transformer (called ZPT). However, in this method, since the electric lines to which a high voltage is applied are put together in the relay switch,
Insulation becomes very difficult. Further, since a high voltage is constantly applied, it cannot withstand long-term reliability.
In the past, many accidents occurred in this area, and it was necessary to regularly replace the distribution lines in the relay switch to prevent them.

FIG. 7 shows the installation situation of the relay switch on the utility pole. The three-phase distribution line 2 is installed on the telephone pole. The distribution line 2 is fixed to and pulled by the armor 4 on the utility pole by the tension insulators 3 provided at regular intervals on the utility pole 1. In FIG. 7, the distribution line 2 is in a slack-free state, and a device such as a relay switch 5 is installed during the next connection. The three-phase distribution line 2 indicated by the arrow 6 is connected to the three-phase distribution line 2 indicated by the arrow 7 through the insulator 3 and the relay switch 5. Inside the relay switch 5 shown in FIG. 7, the ZCT or ZPT and the distribution line cutoff switch (both not shown) are built in, and the ZCT or ZPT detects an abnormality in the middle of the distribution line. , It is to shut down the communication contact or switch to the substation. Such an abnormality is configured to be transmitted to a substation or the like through a communication line 8 installed in the middle of the electric pole 1.

[0005]

[Problems to be Solved by the Invention] As shown in FIG.
The three distribution lines 2 are guided into the relay switch 5 and further Z
Focus on areas such as CT. Even in the case of ZPT, it will be connected via a capacitor or the like. For this reason, the interphase voltage of the distribution line is concentrated in a very narrow place, and insulation cannot be maintained depending on deterioration due to long-term use or the airtight state of the relay switch 5, resulting in short circuit between lines or distribution line In some cases, the cause of the accident itself occurred due to the progress of equipment short circuits.

The distribution line monitoring device constantly monitors the current and voltage flowing through the distribution line in order to detect or predict an accident. This information is
It must be stable and stable under all weather conditions. Therefore, it is desired that even when this device is configured differently, it is not subject to climate change as in the conventional relay switch. The main changes in climate are wetness due to rain, snowfall, etc.In addition, if the configuration is such that each of the three-phase distribution lines is monitored individually, the variation in characteristics of the detection means is required to be negligible. It

The present invention is intended to overcome such problems and install a monitoring device in a state where three-phase distribution lines are installed at regular intervals to obtain information about the distribution lines.

[0008]

According to the present invention, an optical voltage / current sensor is housed in a case body, and the case body is provided with a recess so that it can be installed on a distribution line. The case body is located on the lower side, and another case body having a distribution line installation concave portion is sandwiched and fixed from above by the distribution line. Inside the upper case body and the lower case body, a capacitor voltage divider for dividing the stray capacitance between the distribution line and the ground is formed by two conductors and built in, and electrically connected in parallel to each other. .

The voltage sensor is connected to the capacitor voltage divider of the lower case and monitors the voltage to ground of the distribution line.

The sensor portion of the distribution line monitoring apparatus of the present invention is directly mounted on the distribution line, and is directly wet by rain, snowfall or snow on the case. It is necessary to make the case body structure so that the output of the internal capacitor voltage divider is not affected even under such a condition. Therefore, the ratio between the size of the capacitor voltage divider housed inside and the size of the case body is important, and the dimension in the direction parallel to the distribution line of the case body is more than twice the length of the capacitor voltage divider. To do.

In addition, the stray capacitance between the distribution line and the ground body is 2
Of the outer surface of the case body that houses the voltage divider that divides the capacitor by one conductor, the outer surface of the distribution line and any outer surface portion facing the outer conductor of the capacitor voltage divider are separated from the center of the distribution line by 5 cm or more. Make up the case.

Further, the surface of the outer case is provided with a concavo-convex portion, the creepage distance between the arbitrary outer surface of the upper and lower case bodies and the distribution line is increased, and the resistance value is always maintained at 1.0 * 10 ⁺⁹ Ω or more.

[0013]

According to the present invention, the potential change of the conductor portion such as the voltage divider for the voltage sensor caused by the change of the floating capacitance between the ground due to the contaminant such as rain or snow by operating the shape of the optical sensor outer case of the distribution line monitoring device. The fluctuation of the characteristics of the distribution line monitoring device due to is reduced.

[0014]

The present invention will be described in detail below. First, the outline of the optical voltage sensor will be briefly described. The optical voltage sensor uses the Pockels effect and senses the amount of change in the birefringence of the crystal with respect to the electric field when light passes through the Pockels element, and detects the electric field. In the present invention, the current sensor is housed in the case body at the same time as the voltage sensor, so an outline of the optical current sensor will also be described.

The optical type current sensor utilizes the Faraday effect and detects a magnetic field generated in the periphery when a current flows through an electric line by the rotation angle of light passing through the Faraday element. FIG. 5 shows a schematic diagram in which such a voltage sensor and a current sensor are integrated and installed on a distribution line.

More specifically, a horseshoe-shaped core 12 having a current sensor gap 13 is installed on the distribution line 2, and the optical current sensor 11 is arranged in the gap 13. The optical voltage sensor 9 is provided with a capacitor voltage divider 10 for dividing stray capacitance, and two conductors of the voltage divider are connected to terminals (not shown) of the optical voltage sensor 9.
An optical fiber 15 for incidence and emission is connected to the optical voltage / current sensor, and one optical fiber cable 14 is formed midway and is guided to a connector 19 at the end.

FIG. 6A shows an equivalent circuit between the distribution line, the voltage sensor and the ground. A capacitor voltage divider and a voltage sensor are installed between the distribution line 2 and the ground 42. C ₁ 43 is the capacitance between the conductor of the distribution line and the inner electrode of the capacitor voltage divider, and C ₂ 44 is the capacitance between the inner electrode and the outer electrode of the capacitor voltage divider. C ₃ 45 is a capacitance between terminals of the voltage sensor connected in parallel to the inner and outer electrodes of the divider capacitive divider. C ₄ 46 is an electrostatic capacitance including the air formed between the outer electrode and the earth divider capacitive divider.

This C₁ 43, C₂ 44, C₃ 45, C_Four 
C out of 46₁ 43, C₂ 44, C ₃ 45 is a component
C can be determined by composition_Four Only 46 is affected by atmospheric humidity
It is greatly affected by external factors such as where
Change. Also, between the outer electrode of the capacitor voltage divider and the ground
In addition, if a water film that can serve as an electrode or snow is formed,
The divided voltage output of the capacitor voltage divider will fluctuate. this
C_Four The divided voltage from the capacitor voltage divider which is not affected by 46
It tries to get the output.

FIG. 6B shows a place which is considered to change due to external influence from the equivalent circuit. When the side surface or the outer circumference of the distribution line monitoring device gets wet, the position and the high potential of the outer electrode of the capacitor voltage divider with respect to the ground. The department gets confused and fluctuates. At that time, the capacitance between the earth and the earth becomes a variable capacitance such as C ₄ '47 due to a change in the area facing the earth. As described above, the present invention takes measures against a portion affected by water such as rain and snow.

A detailed example of the present invention will be described below. FIG. 1 shows a perspective view of the configuration of a distribution line monitoring device of the present invention. In the distribution line 2, the lower case body 19 and the upper case body 18 are sandwiched from above and below, and the lower case body 1
An optical current sensor 11, a voltage sensor 9, and
The outer electrode 21 and the inner electrode 22 of the parallel capacitor voltage divider for the voltage sensor are installed. Meanwhile, the outer electrode 16 and the inner electrode 17 of another parallel capacitor voltage divider for the voltage sensor are installed inside the upper case body.
1 and the electrode 17 and the electrode 22 are electrically connected by the conductor 23, that is, the two capacitor voltage dividers are connected in parallel, and further, the capacitor voltage divider with the lower case body incorporated is the conductor 1.
It is connected to the voltage sensor 9 at 8. Further, the horseshoe-shaped core 12 for a current sensor circulates around the distribution line 2 and is installed so that the current sensor 11 inside the lower case comes to the position of the gap 13. Light input and output of the current sensor 11 and the voltage sensor 9 is performed by an optical fiber 15 and is connected to an optical fiber cable 14 introduced from the outside in the lower case body 19.
By the way, in this optical sensor configuration, the relationship between the distance from the center of the distribution line to the surface of the outer case and the rate of change of the voltage divider output due to contamination is as shown in FIG. From FIG. 3, if the distance from the center of the distribution line to the surface of the outer case is 5 cm or more, the output fluctuation of the voltage divider can be suppressed to 10% or less (hatched portion).
In this embodiment, the electrode 22 and the electrode 17 are close to the distribution line 2, and although not shown in FIG. 1, the shortest distance between the inner electrode 17 and the outer electrode 16 and the inner electrode 22 and the outer electrode 2 are not shown.
The shortest interval of 1 is equal to about 10 mm, and the upper case body 18
The distance from the arbitrary position of the distribution line 2 of the portion of the outer surface facing the outer electrode 16 and the distance from the arbitrary position of the distribution line 2 of the portion of the outer surface of the lower case body 19 facing the outer electrode 21 are The configuration is separated by about 50 mm or more.
By thus separating the distribution line portion and the outer surfaces of the upper and lower case bodies, even if there is snow on the outside or water gets wet due to rain, the effect can be reduced. Further, as shown in FIG. 1, when a thin collar 20 having sufficient mechanical strength is provided at both ends of the upper case body and the lower case body so as to be perpendicular to the distribution line 2, a portion which is not polluted by rain or snow is formed, High resistance between an arbitrary position on the outer surface of the case body facing the outer electrode 16 and the outer electrode 21 and the distribution line 2 (for example, in the case of a polyethylene case, the surface resistance is 1.0).
* 10 ⁺¹⁶ Ω or more. ) Can be maintained and the effect of contamination can be reduced.

FIG. 2 shows a sectional view of a distribution line monitoring device of the present invention in order to show the positional relationship of each part inside the case body. The relationship between the ratio of the length of the outer case and the voltage divider and the rate of change of the voltage divider output due to contamination is as shown in FIG. 4, and if the length of the outer case is 2.0 times the length of the voltage divider or more, It is known that the output fluctuation of the voltage divider is suppressed by 10%. Therefore, in this embodiment, a portion of the outer surface of the upper case body 18 facing the outer electrode 16 and a portion of the outer surface of the lower case body 19 facing the outer electrode 21, that is, a case parallel to the distribution line 2 By making the length at least twice the length of the capacitor voltage divider (consisting of the electrodes 16 and 17 and the electrodes 21 and 22) of the upper and lower cases, the influence of contamination can be reduced. Further, in the length direction, it is about 2.5 times that of the condenser voltage divider.

In the present invention, the drawings in which all the configurations shown in the embodiments are adopted are shown, but the inventions of each invention alone or in combination are effective. In the present embodiment, the description has been made with only one distribution line, but the same configuration and effect can be obtained when each is installed in a three-phase distribution line.

The electrode shape of the voltage sensor voltage divider may be arbitrary as long as the required voltage intensity can be obtained.

[0024]

As described above, according to the present invention, the following effects can be obtained. That is, in a distribution line monitoring device that detects a voltage or a current by an optical method, it is possible to reduce a change in characteristics, particularly a change in characteristics due to wetness by rainwater, and a change in characteristics due to snow, and to provide a device with good stability. Further, according to this configuration, it is possible without making the device shape particularly large.

[Brief description of drawings]

FIG. 1 is a configuration perspective view of a distribution line monitoring device according to an embodiment of the present invention.

FIG. 2 is a sectional view of the device.

[Fig. 3] System diagram between the distance from the center of the distribution line to the surface of the outer case and the voltage divider output fluctuation at the time of contamination.

FIG. 4 is a system diagram between the ratio of the length of the outer case to the length of the voltage divider and the voltage divider output fluctuation at the time of fouling.

FIG. 5 is a conceptual diagram of the same device using an optical voltage sensor and current sensor.

FIG. 6 is an equivalent circuit diagram between the distribution line on the voltage sensor side of the device, the capacitor voltage divider, and the ground, and an equivalent circuit diagram when the distribution line, the capacitor voltage divider, and the ground are externally affected.

[Fig. 7] Installation view of a conventional relay switch with a built-in zero-phase current transformer on a utility pole

[Explanation of symbols]

1 utility pole 2 distribution lines 3 Zhang insulator 4 armor 5 relay switches 8 communication lines 9 Voltage sensor 10 condenser voltage divider 11 Current sensor 12 High permeability horseshoe core 13 Gaps 14 Optical fiber cable 15 Optical fiber core 16 Outer electrode of condenser voltage divider with built-in upper case body 17 Inner electrode of condenser voltage divider with built-in upper case body 18 Upper case body 19 Lower case body 20 brim 21 Lower case body built-in condenser voltage divider outer electrode 22 Inner electrode of condenser voltage divider with built-in upper case body 23 conductor wire 24 conductor wire

Claims (2)

[Claims] 1. A case which is composed of two parts, an upper part and a lower part, and which fixes a distribution line by sandwiching it, and a voltage divider which divides a stray capacitance between the distribution line and the ground into a capacitor by at least one of the two cases. A voltage detecting means for detecting the voltage divided by the voltage divider, a high-permeability core that circulates around the distribution line, and a magnetic flux detecting means for detecting a change in the magnetic flux collected by the core. A distribution line monitoring device, wherein, of the outer surface of the case that houses the pressure device, an outer surface portion of the distribution line facing the distribution conductor and the outer conductor of the voltage divider is separated from the center of the distribution line by 5 cm or more. 2. A case composed of two parts, an upper part and a lower part, for sandwiching and fixing a distribution line, and a voltage divider for dividing the stray capacitance between the distribution line and the ground into a capacitor by at least one of the two cases. A voltage detecting means for detecting the voltage divided by the voltage divider, a high-permeability core that circulates around the distribution line, and a magnetic flux detecting means for detecting a change in the magnetic flux collected by the core. A distribution line monitoring device, wherein a dimension of the case housing the pressure device in a direction parallel to the distribution line is at least twice as long as a length of the voltage divider in a direction parallel to the distribution line.