JPH0348606B2 - - Google Patents

Description

[Detailed Description of the Invention] Purpose of the Invention (Field of Industrial Application) The present invention relates to an insulator with a lightning protection function used in power transmission lines or distribution lines, and particularly relates to an insulator with a built-in voltage sensor using optical electrolytic measurement means. Regarding type lightning insulators.

(Prior Art) Conventionally, on power transmission lines or distribution lines, a transformer is installed on the line at a substation to detect fault voltage, operate a relay, and trip a circuit breaker to protect the line.

By the way, the devices that have been used to date to detect voltage in paths are separate from the insulators that support the conductors, and not only do they not have sufficient measurement accuracy, but
Due to their large size, installation work at the measurement location was complicated, and their installation often spoiled the aesthetic appearance of the railroad tracks. For this reason, an insulator disclosed in Japanese Unexamined Patent Publication No. 134395/1983 was proposed as an insulator with a built-in voltage detection device capable of detecting voltage.

As shown in FIG. 4, this insulator has a cavity 32 inside an insulator body 31 made of porcelain, and a hole 33 communicating with the cavity 32 at the top of the insulator body 31. A ceramic body 34 mainly composed of barium titanate or the like was fitted and fixed. Furthermore, the ceramic body 3
An electrode 37 provided with a conductor support portion 36 for supporting the conductor 35 was integrally provided at the upper end of 4, and an electrode 38 was integrally provided at the lower end. A lead wire 39 led out to the outside of the insulator is connected to the electrode 38, and the insulator body 3
1, a base metal fitting 40 was integrally fitted with cement.

With this, the insulator main body 31 is connected to the conductor 35 of the line.
Since the ceramic body 34 is interposed between the electrode 37 and the electrode 38, the electrodes 37 and 38 act as electrode plates, and the ceramic body 34 acts as a dielectric with a high permittivity. , a ceramic capacitor with large capacitance is formed. Therefore, by connecting the lead wire 39 connected to the electrode 38 to a measuring device, the line voltage can be easily detected without being affected by contamination on the outer peripheral surface of the insulator body 31.

On the other hand, in power transmission lines or distribution lines, in addition to supporting conductors, when flashover occurs due to overvoltage due to lightning surges, it is necessary to block the accompanying current and prevent wire breakage and damage to the insulator body due to follow-on arc. Lightning insulators with built-in nonlinear resistance elements were used.

(Problems to be Solved by the Invention) However, the above-mentioned insulator with a built-in voltage detection device has the drawback that the lead wire 39 inside the insulator receives electromagnetic induction from the outside, resulting in a reduction in the S/N ratio. In particular, in recent years, in order to further improve the reliability of power transmission lines and distribution lines, it has become necessary to detect fault voltages, which have been difficult to detect in the past, so highly accurate measurement of line voltage is desired.

The first object of this invention is to incorporate a voltage sensor made of a lightning optical element inside the insulator body of a lightning insulator, so that the structure is simple and compact, and the line voltage can be easily detected. It is an object of the present invention to provide a lightning insulator with a built-in voltage sensor that can detect the operating state of a lightning arrester without impairing its function, and has a high SN ratio of a detection signal and high measurement accuracy.

In addition to the first purpose, the second purpose is to
It is an object of the present invention to provide a lightning insulator with a built-in voltage sensor that allows easy replacement of a deteriorated nonlinear resistance element.

Structure of the invention (means for solving the problem) In order to achieve the first object, the first invention has the following features:
A charging side electrode 4 and a grounding side electrode 5 are provided at both upper and lower ends of the hollow insulator main body 1, and a charging side discharge electrode 14 and an installation side are provided in the hollow portion 1a and are arranged facing each other with a predetermined discharge gap G. In an insulator in which a discharge electrode 15 and a non-linear resistance element 13 are connected in series, an electro-optical element is interposed between the discharge electrodes 14 and 15, and an optical power is applied to the element from the outside. optical fibers 20a and 20b for supplying light and guiding the light modulated within the electro-optical element to the outside.
A configuration is adopted in which the .

Next, in order to achieve the second object, the second invention includes a energizing side electrode 4 and a grounding side electrode 5 at both upper and lower ends of the hollow insulator body 23, and
c, in an insulator in which a non-linear resistance element 13 is connected in series with a energized discharge electrode 14 and a grounded discharge electrode 15 which are arranged facing each other with a predetermined discharge gap G, both of the discharge electrodes 14 and 15 are connected in series. An electro-optical element is interposed therebetween, and an optical fiber 20 is provided for supplying optical power to the electro-optical element from the outside and guiding light modulated within the electro-optical element to the outside.
a, 20b, and separate the insulator body 23 from the upper and lower portions in order to separate the accommodating portion of the non-linear resistance element 13 from the accommodating portions of both the discharge electrodes 14, 15 and the electro-optical element. Insulator 23a,
23b and is formed separately and connected to each other.

(Function) By employing the above configuration, the present invention functions as follows.

In the first invention, a voltage applied to a conductor supported by an insulator is applied to a discharge electrode, an electro-optical element, and a nonlinear resistance element on the power supply side and the ground side through the power supply side electrode. At this time, optical power emitted from a light source such as a light emitting diode outside the insulator is guided to the electro-optic element through an optical fiber for incident light, and while the light passes through the electro-optical element, the electric field strength between the discharge electrodes is In other words, the intensity is modulated according to the line voltage.

Furthermore, this intensity-modulated optical signal is led out to the outside of the insulator through an optical fiber for emitted light, guided to a light receiving element, becomes an electric signal, and the line voltage is measured.

By the way, when a lightning surge enters a conductor, an overvoltage is applied to the discharge gap and the nonlinear resistance element. At this time, a flashover occurs in the discharge gap, and the current flows to the ground via the nonlinear resistance element and the ground electrode. Incidentally, the following current caused by this is interrupted by the nonlinear resistance element instantaneously recovering its resistance value, and the arc is extinguished.

The voltage change at this time is transmitted to a measuring device outside the insulator and measured by the same action as the electro-optical element and optical fiber described above.

Next, in the second invention, in addition to the effect of the first invention,
By separating the upper and lower insulators of the insulator body, a deteriorated nonlinear resistance element can be replaced with a new one.

(Example) Hereinafter, an example embodying the first invention will be described with reference to FIG.

In the drawing, 1 is a hollow clamp-to-spline post type insulator body made of porcelain, and flange fittings 2 and 3 are bonded with cement to the outer periphery of its upper and lower ends. Electrode 4
However, the ground side electrodes 5 are fastened to the flange fittings 3, respectively. Reference numeral 6 denotes a conductor such as an electric wire, which is fitted into the upper concave groove 4a of the power supply side electrode 4 via a conductive washer 7. 8
is a clamp fitting for gripping the conductor 6,
It is engaged with a bolt 10 which is screwed into a screw hole (not shown) in the upper part of the energizing side electrode 4 and tightened with a nut 9, and is fastened and fixed with a nut 11. 12
is an insulating cover that covers the insulator head.

Reference numeral 13 denotes a hollow nonlinear resistance element mainly composed of zinc oxide, which is fitted into the lower half of the hollow part 1a of the insulator body 1 and whose lower end is in contact with the ground electrode 5. It has nonlinear current characteristics and large capacitance. Reference numerals 14 and 15 denote discharge electrodes on the power supply side and the ground side, each having a short cylindrical shape with a bottom and arranged in series above and below the non-linear resistance element 13 with an electrode plate 16 interposed therebetween; 14a,
A discharge gap G is formed between 15a. 17 is a Pockels element as an electro-optical element with insulation supported on the bottom surface of the ground side discharge electrode; 18
is an insulating spacer interposed between the Pockels element 17 and the charging side discharge electrode. Reference numeral 25 denotes a spring for electrically connecting and mechanically fixing the energizing side discharge electrode 14 and the energizing side electrode 4.

Reference numerals 20a and 20b are a pair of optical fibers for human light and emitted light having high insulation properties and non-inductive properties, which are inserted into the cavity 13a of the non-linear resistance element 13, and one end of which is inserted into the cavity 13a of the non-linear resistance element 13. In element 17,
The other end is connected to an optical connector 21 that is fitted and fixed to the ground side electrode 5. 22 is a resin, compound, or insulating oil that surrounds the optical fibers 20a, 20b and fills the cavity 13a;
It is an insulating material such as _SF6 gas.

Next, the operation of the voltage sensor built-in lightning insulator constructed as described above will be explained.

Now, when a voltage is applied to the conductor 6 shown in FIG. A voltage is applied to the Pockels element 17 , the insulating spacer 18 , the charging side and grounding side discharge electrodes 14 and 15 , and the element 13 . Incidentally, since the Pockels element 17, the insulating spacer 18, and the element 13 having a large capacitance are each connected in series, the shared voltage of the former is relatively higher than that of the latter.

At this time, the charging side and the grounding side discharge electrodes 14 and 15
An electric field is generated in the discharge gap G, and this electric field acts on the Pockels element 17. Furthermore, since the Pockels element 17 is located at the center of the discharge electrodes 14 and 15, the electric field within and around the Pockels element 17 is hardly affected by disturbances in the external electric field, and the outer surface of the insulator body 1 is not contaminated. However, even if a leakage current occurs on the outer surface and the potential distribution on the outer surface changes, the change in the electric field acting on the Pockels element 17 is extremely small. As a result, the Pockels element 1
7 is always applied with an even and stable electric field.

Next, an optical connector 2 is connected from a light source (for example, a light emitting diode) (not shown) outside the insulator body 1.
The optical power is transmitted to the incident light optical fiber 20a through the Pockels element 17, and while the light passes through the Pockels element 17, the phase of the light changes depending on the electric field intensity, that is, the voltage of the conductor 6, due to the Pockels effect. Upon receiving the modulation, the polarization element added to the Pockels element 17 modulates the intensity. Next, this modulated signal is transmitted through the emitted light optical fiber 20b without receiving electromagnetic induction from the outside, and guided to a light receiver (not shown) outside the insulator via the optical connector 21, and is then converted into an electrical signal. The voltage is then measured.

By the way, in this first invention, as an inherent function of the lightning insulator, when an overvoltage lightning surge enters the conductor 6,
between the discharge electrodes 14 and 15 and the nonlinear resistance element 1 via the washer 7, the overcurrent side electrode 4, and the spring 25.
Overvoltage is applied to 3. At this time, a flashover occurs between the discharge electrodes 14 and 15 via the discharge gap G. At this time, the current flows in the order of the electrode plate 16, the nonlinear resistance element 13, and the grounding side electrode 5, and then flows to the ground due to a grounding object (not shown), but the following current is nonlinear. The resistance element 13 instantaneously recovers its resistance value and interrupts this, and the arc is extinguished.

Note that the voltage change indicating the operation of the lightning arrester is caused by the electric field applied to the Pockels element 17 instantaneously becoming zero during flashover between the discharge electrodes.
By the action of b, it is transmitted to a measuring device outside the insulator and can be detected.

By the way, the lightning discharge ends 14a, 15a of the discharge electrodes 14, 15 on the charging side and the grounding side in this embodiment are as follows.
Each may be formed into a round shape as shown in FIG.

Next, the configuration of the second invention will be explained with reference to FIG. It should be noted that members having the same functions as those in the embodiment shown in FIG. 1 are designated by the same numbers and their explanations are omitted, and only the differences will be explained.

In the drawing, reference numeral 23 denotes a hollow clamp-to-spline post type insulator body made of porcelain, which is divided into an upper insulator 23a and a lower insulator 23b, and a female threaded cylinder 24 fixed to the outer periphery of the lower end of the upper insulator 23a.
The lower insulator 23b is separably fixed to the lower insulator 23b by screwing a male threaded tube 24b fixed to the outer periphery of the upper end of the lower insulator 23b. Reference numeral 25 denotes a spring interposed between the energizing side electrode 4 and the energizing side discharge electrode 14 inside the hollow portion 23c via locking tubes 26a and 26b, and electrically connected between the two electrodes, and 27 a grounding element. This is a spring interposed between the side discharge electrode 15 and the electrode plate 16. 28 is the ground side discharge electrode 15 and the electrode plate 1
This optical connector is located between the optical fibers 6 and 6, and connects the pocket element 17 and the optical fibers 20a, 20b in a detachable manner.

Next, the operation of the voltage sensor built-in lightning insulator constructed as described above will be explained.

This lightning insulator functions in the same manner as the lightning insulator of the embodiment of the first invention with respect to the voltage of the conductor 6 and the interruption of follow-on arcs caused by overvoltage lightning surges and the detection of voltage changes at that time.

By the way, in this lightning insulator, the female threaded cylinder 24a
When the male threaded tube 24b is unscrewed, the insulator body 23 is separated into an upper insulator 23a and a lower insulator 23b. Thereafter, the Pockels element 17 housed inside the insulator body 23 and the optical fibers 20a, 2
If the connection of 0b is released by the optical connector 28,
The deteriorated nonlinear resistance element 13 can be replaced with a new one. Next, a new non-linear resistance element 13 is connected, and the upper insulator 23a and the lower insulator 23b are connected to the female threaded cylinder 24a and the male threaded cylinder 2.
4b, the upper insulator 23a containing the electro-optical element can be reused.

In this lightning insulator, even if the nonlinear resistance element 13 deteriorates and the original function of the lightning insulator deteriorates, there is no need to replace the entire insulator, and the expensive Pockels element 17 can be reused, making it economical. It is.

Note that the optical fibers 20a and 20b used in the embodiments of the first and second inventions include not only single optical fibers but also optical fiber cables in which a single optical fiber is covered and protected with a PVC sheath or the like. It is something.

Further, the voltage sensor built-in lightning insulators of the first invention and the second invention each support the conductor 6 by:
In addition to being installed at required locations such as substations as in the past, if it is installed on each utility pole along the power line to measure the voltage and transmit the signal, it is possible to prevent ground faults at each feeder. , accidents such as short circuits, and the operating status of the lightning arrester can be centrally monitored. Further, in the electric line, it is also possible to appropriately measure the voltage via the optical connector 21 by using a portable voltage measuring device.

Effects of the Invention As detailed above, the first invention accommodates a discharge gap formed by a pair of discharge electrodes facing each other and a nonlinear resistance element connected in series inside a lightning insulator, and Since an optical fiber is connected between them with an electro-optical element interposed between them, line voltage can be detected without impairing the original function of the lightning insulator. In addition to effectively reinforcing the insulation between the measurement section including elements and the voltage detection section inside the insulator, the insulator itself does not require a large space for the built-in sensor, and the structure is not only simple and compact, but also completely free of charge. It has many advantages, including high precision guidance and the ability to detect the operating status of a lightning arrester.

Moreover, the second invention has, in addition to the effects of the first invention,
By separating the insulator body, the nonlinear resistance elements housed inside the insulator can be replaced, so if the elements are in a defective state, they can be replaced freely and there is no need to replace the entire insulator, which is very convenient. It is possible to provide an economical and highly useful lightning insulator.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the first invention;
3 is a sectional view showing another example of the discharge gap, and FIG. 4 is a sectional view showing a conventional example. 1, 23...Insulator body, 4...Electrifying side electrode, 5
...Grounding side electrode, 6...Conductor, 13...Nonlinear resistance element, 14...Charging side discharge electrode, 15...Grounding side discharge electrode, 17...Pockels element, 20
a, 20b...optical fiber, 21, 28...optical connector, 24a...female thread tube, 24b...male thread tube.

Claims (1)

[Scope of Claims] 1. A hollow insulator body 1 is provided with a charging side electrode 4 and a grounding side electrode 5 at both upper and lower ends, and the hollow part 1a is provided with a charging side electrode 4 and a grounding side electrode 5, which are arranged facing each other with a predetermined discharge gap G. In an insulator in which a side discharge electrode 14, a ground side discharge electrode 15, and a nonlinear resistance element 13 are connected in series, an electro-optical element is interposed between both the discharge electrodes 14 and 15, and the electro-optical element has a A lightning insulator with a built-in voltage sensor, characterized in that optical fibers 20a and 20b are connected for supplying optical power to the element from the outside and guiding light modulated by the element to the outside. 2 Discharge electrodes 14, 15 on the energizing side and the grounding side
The voltage sensor built-in lightning insulator according to claim 1, wherein an insulating spacer 18 and an electro-optical element are interposed in series connection. 3. The voltage sensor built-in lightning insulator according to claim 1, wherein the electro-optical element is a Pockels element 17. 4 The nonlinear resistance element 13 is an optical fiber 20a,
The lightning insulator with a built-in voltage sensor according to claim 1, which is formed into a hollow shape so that the voltage sensor 20b can be inserted therethrough, and is mainly made of zinc oxide (ZnO). 5. The voltage sensor built-in lightning insulator according to claim 1, wherein the ground side electrode 5 is provided with an optical connector 21 for connecting optical fibers 20a and 20b. 6 The hollow insulator main body 23 is provided with a charging side electrode 4 and a grounding side electrode 5 at both upper and lower ends, and the hollow part 23c
In an insulator in which a non-linear resistance element 13 is connected in series with a energized discharge electrode 14 and a grounded discharge electrode 15 which are arranged facing each other with a predetermined discharge gap G, a An electro-optical element is interposed between the electro-optical element and optical fibers 20a and 20 for supplying optical power to the element from the outside and guiding light modulated within the element to the outside.
b, and the nonlinear resistance element 1
In order to separate the insulator main body 23 from the upper and lower insulators 23a,
A lightning insulator with a built-in voltage sensor, characterized in that it is formed separately from 23b and connected to each other. 7. The voltage sensor built-in lightning insulator according to claim 6, wherein the upper insulator 23a and the lower insulator 23b are removably fitted and fixed by a female thread tube 24a and a male thread tube 24b.