JPH01284775A - Corona sound detecting device for insulator - Google Patents

Abstract

PURPOSE:To detect a corona sound generated at an insulator with extremely high sensitivity and accuracy by providing a resonator which resonates and extracts only the sound of a specific frequency component and extracting only a corona sound component by resonance. CONSTITUTION:The annular resonator 4 is installed through a disk 3 at the circumferential part centering on the axis of an insulator string 2. The resonance center frequency of the resonator 4 is set to double as high as the commercial electric power frequency. An acoustic sensor 5 consisting of, for example, a piezoelectric microphone is fitted in the resonator 4. If the corona sound is generated owing to corona discharge due to deterioration of an insulator, the corona sound enters the resonator 4 together with an ambient external noise and only the specific frequency component of the corona sound is emphasized and extracted here. Consequently, the corona sound generated at the insulator is detected with extremely high sensitivity and accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an insulator corona sound detection device for detecting corona sound generated from an insulator used for electrical insulation of power transmission lines.

[Conventional technology] Overhead power transmission lines are essential equipment for power supply operations, and failure of this equipment can have an extremely serious impact on today's highly electrified society, paralyzing social functions in all areas. is inevitable.

For this reason, extremely high reliability is required of power transmission lines, and although designs and quality assurance have been implemented to meet this requirement, it is currently nearly impossible to completely eliminate breakdowns and accidents related to power transmission lines. It is.

Among the faults that occur in power transmission lines, the most serious ones are electrical faults that cause power transmission to stop, and are mainly related to electrical insulation performance in the case of ground faults or short circuit faults. Electrical insulation of power transmission lines is achieved by insulators at the tower support parts, and by air insulation with a certain distance between the towers, but the insulators at the tower support parts are susceptible to rain, salt damage, etc. Its insulation performance changes greatly due to contamination. Therefore, if the insulation performance of insulators can be frequently monitored and deterioration of insulation performance can be detected before serious accidents such as insulator flashovers occur, serious accidents on power transmission lines can be prevented.

A so-called corona discharge occurs as a sign of deterioration of the insulation of the insulator, and by monitoring the occurrence of this corona discharge, deterioration of the insulation of the insulator can be detected in advance.

To monitor the occurrence of corona discharge, there are two methods: an electrical method that measures the corona discharge current of the insulator and directly detects corona discharge from this current value; There is also an acoustic method to indirectly detect corona discharge.

Of these, the latter method of detecting corona noise, in which a sound level meter is temporarily installed on the ground or near the insulator for noise observation, is extremely simple and technically attractive.

[Problem to be solved by the invention] However, as mentioned above, in the conventional method of detecting corona noise, since it is observed together with surrounding noise on the ground or on a steel tower near the insulator, it is very difficult to distinguish the corona noise. There was a problem.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art by emphasizing and detecting only the sound of a specific frequency component using resonance phenomenon, and to reliably detect the corona sound generated by the insulator. An object of the present invention is to provide a novel insulator corona sound detection device capable of detecting.

[Means for Solving the Problems] The insulator corona sound detection device of the present invention resonates and extracts only the sound of a specific frequency component from the corona sound generated from the insulator on the ground potential side of the insulator that insulates and supports the power transmission line. A resonator is provided, and an acoustic sensor is attached to the resonator to detect the sound of a specific frequency component extracted from the corona sound.

Here, the specific frequency component refers to a component that has a higher sound pressure level than other frequency components and allows corona sound to be distinguished from external noise. Note that the insulator also includes an insulator chain.

[Operation] When corona sound is generated due to corona discharge due to deterioration of the insulator, this corona sound is mixed with surrounding external noise and enters the resonator, where only specific frequency components of the corona sound are emphasized and extracted. . The extracted sound components are captured by an acoustic sensor and converted into electrical signals.

[Embodiment] The insulator corona sound detection device of the present invention will be described in detail below.

FIG. 2 shows an example of the measurement results of the frequency distribution of corona sound, which is a detection target of the insulator corona sound detection device of the present invention. As shown in the figure, the spectrum of corona sound includes irregular noise components over a wide range of frequencies, including a frequency of 100Hz, which is twice the commercial power frequency (50Hz).
It can be seen that there is a noticeable peak P at z. Therefore,
If the detection is focused on 100+12, it becomes possible to accurately detect the corona sound. This 100H2 component sound is called a corona hum sound.

FIG. 1 is a block diagram showing an embodiment of the insulator corona sound detection device of the present invention. The power transmission line 1 is normally suspended and held by an insulator chain 2 at a steel tower portion. A disk 3 is attached near the end of the insulator chain 2 that is attached to the steel tower on the ground potential side, and a hollow annular resonator 4 is installed around the outer periphery of the disk 3. That is, the annular resonator 4 is installed on the circumference of the insulator chain 2 with the disk 3 interposed therebetween. The resonance center frequency of this resonator 4 is set to be twice the commercial power frequency. For example, for 50Hz, 100
In the case of Hz and 60 tlz, the number is 12 times 2. but.

The resonance center frequency is not necessarily limited to twice the commercial power frequency, but may be an integral multiple of the commercial power frequency. Further, the resonator 4 is provided with a plurality of holes 6 along the circumferential direction,
It is designed to capture sound propagating through space. Resonator 4
Inside the system, the corona hum sound among the captured sounds is amplified, and noise at other frequencies is conversely reduced. An acoustic sensor 5 composed of, for example, a piezoelectric microphone is attached inside the resonator 4, and the acoustic sensor 5 detects the emphasized corona hum sound.

The detection signal is converted into light, for example, and then transmitted to a central monitoring station using an optical fiber of a combined optical fiber overhead ground line.

Therefore, since the normal noise measurement method detects the overall sound level including external noise, it is difficult to accurately identify the corona sound.In contrast, the insulator corona sound detection device of this embodiment Corona sounds can be detected with extremely high sensitivity and accuracy because only the sound components are emphasized using resonance phenomena.

In particular, since the resonator 4 is installed on the ground potential side, corona noise generated from any of the insulators constituting the insulator chain 2 can be effectively captured without omission. Further, the resonator 4 is formed into an annular shape and is installed on the axis of the insulator 3!2, so that the generated corona sound can be effectively caught regardless of the deterioration location of the insulator chain 2 in the circumferential direction.

Note that the resonator 4 is provided with a plurality of holes 6 to capture sound propagating through the space, but even if no holes 6 are provided, the sound propagating from the insulator chain 2 to the disk 3 cannot be detected. It is possible.

[Effects of the Invention] According to the present invention, since only the corona sound component is extracted by resonance, the corona sound generated in the insulator can be detected with extremely high sensitivity and accuracy regardless of the noise level.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an insulator corona sound detection device according to the present invention, and FIG. 2 is a spectrum diagram showing an example of the frequency distribution of corona sound to be detected. In the figure, 1 is a power transmission line, 2 is an insulator chain, 4 is a resonator, and 5 is an acoustic sensor. Patent applicant: Hitachi Cable Co., Ltd. Patent attorney Yumi Kinuya

Claims (1)

[Claims] 1. A resonator is installed on the ground potential side of the insulator that insulates and supports the power transmission line, and that resonates and extracts only the sound of a specific frequency component from the corona sound generated from the insulator. An insulator corona sound detection device characterized by being equipped with an acoustic sensor that detects the sound of.