JP3061569B2 - Composite insulator bushing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite bushing used in a substation and the like, and more particularly to a device for monitoring a leakage current flowing on a surface of a bushing.

[0002]

2. Description of the Related Art In recent years, glass fiber reinforced plastic FR
Using P as the core material and surrounding it with silicone rubber or EPD
2. Description of the Related Art Composite insulator bushings in which a cap material made of an organic insulating material such as M or EVA is molded are being applied as bushings for various high-voltage devices instead of ceramic insulator bushings.

A composite insulator bushing has various features such as small size, light weight, easy production, explosion proof property, easy handling, and the like. In particular, due to the water repellency of the cap material, the bushing is superior in stain resistance to a porcelain insulator. Therefore, it is possible to set an electrolytic level equal to or higher than that of the porcelain insulator tube when designing the insulation.

[0004]

However, the bushing causes deterioration of insulation due to contamination or partial discharge, etc., due to long-term use, and leakage current flows along the surface. Especially in the case of composite insulators,
Since the cap material is formed of an organic material, damage to the cap material called tracking, erosion or choking can occur due to leakage current,
It has the characteristic that insulation degradation is particularly fast.

SUMMARY OF THE INVENTION It is an object of the present invention to monitor the leakage current flowing on the surface of a composite insulator bushing to accurately grasp the state of deterioration of the composite insulator and prevent dielectric breakdown.

[0006]

In order to achieve the above object, the present invention provides a metal tank on the equipment body side and a cap made of an organic insulator disposed on the line terminal side. In a composite insulator bushing having a composite insulator having a material and a ground-side mounting bracket interposed between the composite insulator and the metal tank, an insulator is interposed between the metal tank and the ground-side mounting bracket. A composite insulator bushing which conducts through a detection impedance and is connected to a means for measuring a leakage current between the two.

In such a configuration, since a potential difference between the metal tank and the ground-side mounting bracket can be detected, a leakage current between the two can be measured. According to a second aspect of the present invention, there is provided a metal tank on a device body side, a composite insulator tube disposed on a line terminal side and having a cap material made of an organic insulator, and a grounding side interposed between the composite insulator tube and the metal tank. In a composite insulator bushing comprising:
An electrode is provided in the vicinity of the ground-side mounting bracket of the composite porcelain tube, and the electrode and the metal tank or the ground-side mounting bracket are conducted through a detection impedance to measure leakage current therebetween. A composite insulator bushing characterized by being connected is provided.

[0008] Even in such a configuration, since the potential difference between the electrode and the ground-side mounting bracket can be detected, it is possible to measure the leakage current between the two. According to a third aspect of the present invention, there is provided a composite insulator bushing according to the first or second aspect, wherein the detected impedance comprises a resistor or a surge absorbing element connected in parallel to the resistor.

By employing such a configuration, the leakage current flowing on the bushing surface can be accurately measured. According to a fourth aspect of the present invention, there is provided the composite insulator bushing according to any one of the first to third aspects, wherein the leakage current measuring means can measure the leakage current separately for each of a plurality of current regions.

By adopting such a configuration, it is possible to accurately measure a leakage current having a wide current range. According to a fifth aspect of the present invention, there is provided the composite insulator bushing according to any one of the first to fourth aspects, wherein the leakage current measuring means can measure the magnitude and frequency of occurrence of a current pulse.

By adopting such a configuration, it is possible to accurately measure a leakage current having an irregular frequency and a variable size. According to a sixth aspect of the present invention, there is provided the composite bushing bushing according to any one of the first to fifth aspects, wherein the leakage current measuring means can record a temporal change in the magnitude and occurrence frequency of the current pulse. I do.

By adopting such a configuration, it is possible to know the change over time of the composite insulator bushing. According to a seventh aspect of the present invention, the leak current measuring means includes a means for issuing an alarm when the magnitude of the current pulse exceeds a predetermined level. A composite insulator bushing as described. By adopting such a configuration, useful information for performing maintenance of the composite insulator bushing can be obtained.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a composite insulator bushing according to the present invention will be described below with reference to FIG. Here, 1 is a composite insulator made of an FRP core and a cap material 8, 2 is a ground-side mounting bracket of the composite insulator, 3 is a metal tank installed on the equipment body side below the bushing, 4 is an insulator. Here, the grounding-side mounting bracket 2 is directly bolted to the metal tank 3, but in the present embodiment, it is characterized in that it is fastened by insulating bolts via the insulator 4. Further, in order to measure the leakage current flowing on the surface of the bushing, that is, the cap member 8, the grounding-side mounting bracket 2 is connected to the leakage current measuring device 10 and is constituted by a resistor or a surge absorbing element connected in parallel to the resistor. Through the impedance 5 to the metal tank 3.

In such a configuration, the ground-side mounting bracket 2
Since the metal tank 3 and the metal tank 3 are insulated from each other, a potential difference occurs due to the leakage current, and the leakage current value can be output through the impedance 5 having a predetermined value.

On the other hand, the leakage current measuring device 10 has a circuit configuration shown in FIG. The leakage current value is input as an input signal through a filter F at the first input stage to remove noise, and then input to a measurement circuit divided and arranged in a parallel number n. In the n measurement circuits, the circuits are configured to handle the measurement for each different current range. The reason is that the leakage current shows a wide range of change from several micro-amps to several amps depending on the weather condition and the deterioration state of the bushing, and the occurrence frequency is extremely irregular. Thus, in order to process such a complicated waveform, it is necessary to count the magnitude and frequency of the pulse for each current range.

In each of the measuring circuits, the input signal passes through the amplifier An, and after the noise is removed again by the filter Fn, the signal is input to the peak hold Pn, and the peak value and the frequency of pulse generation are measured. Then, after being converted into a digital signal by the A / D converter, it is transmitted to the CPU for information processing.

Further, the CPU can add a function capable of recording a change with time of the leakage current so that the change with time of the composite insulator bushing can be known. If a function that can generate an alarm by setting a dangerous signal level in advance is added, useful information for performing maintenance can be obtained.

Next, another embodiment of the present invention will be described with reference to FIG. Due to design restrictions, the insulator 4 is placed between the mounting bracket 2 of the composite insulator bushing and the metal tank 3.
In the case where the leakage current cannot be interposed, an electrode 6 surrounding the body of the composite insulator tube may be attached to the vicinity of the ground-side fitting 2 so that the leakage current can be measured. In this case, an impedance 5 is attached between the electrode 6 and the grounding-side mounting bracket 2 or the metal tank 3 having the same potential as the electrode 6 to detect a leakage current and supply the leakage current to the leakage current measuring device 10. Connecting. The circuit configuration and operation of the leakage current measuring device 10 are the same as in the first embodiment. Also in such a configuration, since the composite insulator 1 as an insulator is interposed between the electrode 6 and the ground-side fitting 2, the potential difference between the two can be detected.

[0019]

As described above, according to the present invention, since the leakage current flowing through the cap material of the composite insulator bushing can be constantly measured, it is possible to accurately grasp the temporal change and deterioration of the composite insulator tube. Yes, dielectric breakdown can be prevented beforehand.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a cross-sectional structure of a composite insulator bushing according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a circuit configuration of a leakage current measuring device.

FIG. 3 is a view schematically showing a cross-sectional structure of a composite insulator bushing according to a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Composite insulator tube, 2 ... Ground side mounting bracket, 3 ... Metal tank, 4 ... Insulator, 5 ... Detection impedance, 8 ... Shade material,
10 ... Leakage current measuring device.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yukiko Akimoto 2-1 Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Inside the Hamakawasaki Plant of Toshiba Corporation (72) Inventor Motoharu Shiiki 2-Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture No. 1 Toshiba Corporation Hamakawasaki Plant (58) Field surveyed (Int. Cl. ⁷ , DB name) H01F 27/00 H01F 27/04

Claims (7)

(57) [Claims] 1. A metal tank on a device main body side, a composite insulator tube disposed on a line terminal side and having a cap material made of an organic insulator, a ground-side mounting bracket interposed between the composite insulator tube and the metal tank, In the composite insulator bushing having the above, an insulator is interposed between the metal tank and the ground-side mounting bracket, and conduction is performed via a detection impedance, and connection is made to a means for measuring a leakage current between the two. A composite insulator bushing characterized by the following. 2. A metal tank on the device body side, a composite insulator tube disposed on the line terminal side and having a cap material made of an organic insulator, a grounding-side mounting bracket interposed between the composite insulator tube and the metal tank, In the composite insulator bushing having an electrode, an electrode is provided in the vicinity of the ground-side mounting bracket of the composite insulator, and the electrode and the metal tank or the ground-side mounting bracket are electrically connected via a detection impedance. A composite insulator bushing connected to means for measuring leakage current. 3. A bushing according to claim 1, wherein said detection impedance comprises a resistor or a surge absorbing element connected in parallel to said resistor. 4. The composite insulator bushing according to claim 1, wherein said leakage current measuring means is capable of dividing and measuring each of a plurality of current regions. 5. The composite insulator bushing according to claim 1, wherein said leakage current measuring means can measure the magnitude and frequency of occurrence of a current pulse. 6. A composite insulator bushing according to claim 1, wherein said leakage current measuring means is capable of recording changes with time in the magnitude and occurrence frequency of a current pulse. 7. The composite insulator tube according to claim 1, wherein said leakage current measuring means includes means for issuing an alarm when the magnitude of the current pulse exceeds a predetermined level. Bushing.