JP3493970B2 - Bushing monitoring device and its monitoring method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bushing monitoring device.
And a monitoring method thereof , and more particularly, to a bushing monitoring device and a monitoring method thereof suitable for checking or monitoring the bushing.

[0002]

2. Description of the Related Art Non-porcelain bushings have water repellency and are therefore excellent in initial insulation performance. However, if the water repellency of the surface of the non-porcelain bushing is impaired due to ultraviolet rays, erosion, corona discharge, etc., the dielectric strength will be significantly reduced. Conventionally, the deterioration of the bushing and the remaining life have been predicted by cutting off the voltage and measuring the color of the bushing surface, the presence or absence of cracks, or the contact angle of a water drop.

However, it is known that the water repellency of the bushing surface has a self-recovering ability and that even if the water repellency is once reduced, it will recover to near the initial state with time. Also, the correlation between dielectric strength and surface color due to deterioration is not necessarily linear. Therefore, it is difficult to accurately predict the deterioration and the remaining life of the non-porcelain bushing by the method as described above.

[0004]

In such a conventional technique, it is necessary to manually stop the voltage in addition to the labor required. Further, since the accuracy of predicting deterioration and remaining life is low, insulation reliability is lowered and maintenance cost of the bushing is increased. The present invention has been made in view of the above points, and an object of the present invention is to perform bushing monitoring capable of accurately predicting deterioration and remaining life of a bushing, reducing maintenance costs, and improving insulation reliability. An apparatus and a monitoring method thereof are provided.

[0005]

[Means for Solving the Problems] To achieve the above object
The bushing monitoring device of the present invention has a center conductor inside.
Current transformer that measures the leakage current through the bushing
Pulse detection to measure pulse due to resistance and partial discharge
And the signal measured by the current transformer and pulse detector
Peak leakage current obtained by
Deterioration of the bushing due to pulse frequency and duration
Or an arithmetic processing unit for determining the remaining life
Or through a bushing with a central conductor inside
Current transformer for measuring leakage current and the surface of the bushing
The camera that monitors the data and the data captured by the camera.
Image processing to reduce the size of water droplets on the bushing surface.
Is an image processing device that determines the contact angle of water droplets, and the current transformer
The measured bushing leakage current and the image processing device
By inputting the processed data
Arithmetic processing to determine deterioration of bushing or remaining life
And a device. In addition, according to the present invention
The bushing monitoring method is a bushing having a center conductor inside.
Leakage current and partial discharge pulse through the
Obtained by processing the two signals from the processing device
Peak leakage current, pulse frequency and duration
Whether the bushing is deteriorated or the remaining life is judged,
Leakage through a bushing with a central conductor inside
With a camera that monitors the current and the surface of the bushing
Bushing table obtained by image processing of captured data
Performed based on the size of the water droplet on the surface or the contact angle of the water droplet.
Even if the bushing is deteriorated by performing arithmetic processing with the arithmetic processor
In other words, the remaining life is determined.

Namely, blanking Tsu <br/> single monitoring device and monitoring method of the present invention configured as described above, it is possible to accurately predict the deterioration and remaining life of the probe ashing, cleaning time and bushing replacement It is possible to reduce the maintenance cost and improve the insulation reliability by optimizing the timing.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the relationship between leakage current and breakdown voltage. The breakdown voltage was expressed as a percentage based on the leakage current in the initial state. It can be seen that the breakdown voltage decreases as the leakage current increases, and there is a correlation between the increase in the leakage current and the decrease rate of the breakdown voltage. In addition, since the leakage current changes with time and weather conditions, in order to understand the state of the bushing installed on site, further consider the deterioration caused by heat and corona discharge due to the leakage current flowing. By making the determination, it is possible to accurately determine the deterioration of the bushing or the remaining life. Therefore, the deterioration and the remaining life of the non-porcelain bushing can be accurately measured by measuring the time during which the non-porcelain bushing is exposed to partial discharge and the leakage current together. FIG. 2 shows an embodiment of the present invention. The bushing 1 and the GIS are insulated from each other by the insulating flange 4, and the leakage current flowing through the bushing 1 is transformed by the current transformer 14
Also, the pulse detector 1 detects the pulse generated by the partial discharge.
It is measured by 0. A bushing monitoring device that determines the deterioration or remaining life of the bushing from the peak leakage current, the pulse generation frequency, and the duration of the two signals by an arithmetic processing device. It has the advantage that the device is relatively simple and easy to apply to conventional GIS.

FIG. 3 shows an embodiment of the present invention. By using resistors instead of current transformers compared to FIG. 2, the monitoring device can be made even lower cost. Also, since the deterioration or remaining life of the bushing can be accurately predicted, the lower shield of the bushing can be simplified,
The cost of the GIS as a whole can be reduced.

FIG. 4 shows an embodiment in which the observation by the camera and the bushing leakage current are combined. Example shown in the figure
Sends the data captured by the CCD camera 15 to the image processing apparatus 16, the image processing apparatus 16 with the water droplet size, or the contact angle of a water droplet determined by image processing, calculates the processing data bushing leakage current by digital arithmetic processing unit 13, the monitoring system der to predict deterioration of the bushing 1, or a remaining life
It Since the degree of deterioration of water repellency and the state of the entire bushing can be obtained from the leakage current by the CCD camera 15, the degree of deterioration can be evaluated more accurately than in combination with partial discharge.

FIG. 5 shows an embodiment in which partial discharge by electromagnetic waves and leakage current of the bushing are combined. Electromagnetic waves generated by corona discharge in the air are generated by the UHF sensor 19
Is detected as a signal having a frequency of several hundred Mhz or less. Therefore, the degree of deterioration of the bushing can be evaluated by processing the corona size and duration together with the bushing leakage current.

FIG. 6 shows a conventional embodiment.

[0012]

As described above, according to the present invention, it is possible to accurately predict the contamination and deterioration of the bushing, and the remaining life of the bushing. Therefore, it is possible to reduce the maintenance cost and improve the insulation reliability.

[Brief description of drawings]

FIG. 1 is a characteristic diagram illustrating a relationship between a leakage current and a breakdown voltage for explaining the present invention.

FIG. 2 is an explanatory diagram of a bushing monitoring device that is an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a bushing monitoring device that is an embodiment of the present invention.

FIG. 4 is an explanatory diagram of a bushing monitoring device that is an embodiment of the present invention.

FIG. 5 is an explanatory diagram of a bushing monitoring device that is an embodiment of the present invention.

FIG. 6 is an explanatory diagram of a conventional bushing monitoring device.

[Explanation of symbols]

1 ... Bushing, 2 ... Bushing upper shield, 3 ... Bushing lower shield, 4 ... Insulation flange, 10 ... Pulse detector, 11 ... Preamplifier, 12 ... Pulse counter, 13 ... Arithmetic processing unit, 14 ... Current transformer, 15 ... CCD
Camera, 16 ... Image processing device, 17 ... Spectrum analyzer, 18 ... Digital converter, 19 ... UHF sensor.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Keisho Endo 7-2-1 Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Power & Electric Development Division (72) Inventor Tokio Yamagoku Hitachi City, Ibaraki Prefecture Kokubun 1-1-1 Machi Co., Ltd. Hitachi Kokubun Plant (72) Inventor Tohoku Hiromichi 1-1-1, Kokubuncho, Hitachi City, Ibaraki Hitachi Ltd. Kokubun Plant (56) References 9-17258 (JP, A) JP-A 1-260371 (JP, A) JP-A 9-105766 (JP, A) JP-A 9-243701 (JP, A) JP-B-35-91 (JP, B1) (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01B 17/00 G01R 31/00 G01R 31/12 H01B 17/26

Claims (2)

(57) [Claims] 1. A current transformer for measuring a leakage current flowing through a bushing having a center conductor therein, a camera for monitoring the surface of the bushing, and a water droplet on the surface of the bushing by image-processing the data captured by the camera. Of the bushing leakage current measured by the current transformer and the processing data obtained by the image processing apparatus are input and arithmetically processed to deteriorate the bushing. Alternatively, the bushing monitoring device is provided with an arithmetic processing unit that determines the remaining life. 2. A leakage current flowing through a bushing having a center conductor inside, and a size of a water droplet on the bushing surface or a contact angle of the water droplet obtained by image processing of data captured by a camera monitoring the surface of the bushing. A bushing monitoring method characterized in that deterioration of the bushing or remaining life is determined by performing arithmetic processing in an arithmetic processing unit based on the above.