Hitachi, Ltd.

Japan Ae Power Systems Corporation

Fumihiro Endo

Tokio Yamagiwa

Tomoaki Utsumi

Toshiaki Rokunohe

Tatsuro Kato

Toshio Ishikawa

Kazuo Kobayashi

Kazuhiro Saito

Jun Ozawa

Kenji Tsuchiya

Yuzuru Kamata

Shuzo Iwaasa

Hiroshi Yamada

Isao Takahashi

Youichi Ohshita

Izumi Yamada

Tomohiro Moriyama

Toyokazu Tanaka

Hashime Nagai

Ryouichi Shinohara

Mitsuo Sawairi

Yukio Kurosawa

Masanori Tsukushi

Kunio Hirasawa

Akira Hashimoto

Yoshio Yoshioka

Shigeo Shiono

Goro Daimon

Katsuji Shindo

Takashi Omori

Ryoichi Shinohara

Yoshitaka Yagihashi

Shunji Ito

Yoshinori Tagawa

Shigeo Kobayashi

Minori Satoh

Kazutoshi Asano

Takuya Sugawara

Kenji Anno

A gas-insulated apparatus is equipped with multiple sensors for sensing a partial discharge signal caused by a foreign substance, and a frequency analyzing section for analyzing the frequency of the sensed partial discharge signal. A defect type judging section estimates the defect type of the foreign substance from the signal obtained through the frequency analysis or from the voltage phase distribution of partial discharge synchronized with the frequency of the voltage applied to the gas-insulated apparatus, and a location determining section estimates the defect location and signal intensity from the multiple partial discharge signals. A defect size calculating section estimates the defect size for each defect type from the signal intensity and field distribution at the defect location. Dielectric breakdown risk evaluation is performed based on the defect size and type, and the insulation failure risk is diagnosed from the partial discharge.

Method and system for monitoring partial discharge in gas-insulated apparatus

In the measurement of partial discharge, a voltage detected by an antenna is input to a spectrum analyzer and a phase difference between an operating voltage and a power supply of the spectrum analyzer is obtained by phase domain analysis using the spectrum analyzer. Based on the phase difference and the voltage phase shift associated with the input impedance of a signal converter circuit, the time axis displayed on the screen of the spectrum analyzer is compensated. After the compensation has been carried out, the voltage detected by the antenna is input into the spectrum analyzer and the partial discharge pattern which synchronizes with the operating voltage is measured by phase domain analysis using the spectrum analyzer.

Method and system for measuring partial discharge

In a gas-insulated switchgear tank in which an electric insulating characteristic is improved by a gas, and which has a vacuum circuit-breaker, a disconnecting switch, and a container in which container the vacuum circuit-breaker and the disconnecting switch are arranged and an inside of which container is adapted to be hermetically sealed and filled with the gas in such a manner that the vacuum circuit-breaker and the disconnecting switch are at least partially surrounded by the gas, the gas includes Nand O.

Gas-insulated switchgear tank

The present invention combines sensor portionsof the device for measuring either current flowing through the line from the power inlet to the power outlet or voltage, or both, and bushingsinstalled at either the power inlet or the power outlet, or both, so as to reduce the size of the gas insulating apparatus. Specifically, the above-mentioned sensor portionsare installed in the space inside the porcelain tubethat constitutes the bushingsAs this space, it is preferable to use the space on the outer-periphery side of the electric field relaxation memberprovided inside the porcelain tube

Gas insulating apparatus and method for locating fault point thereof

The present invention combines sensor portionsof the device for measuring either current flowing through the line from the power inlet to the power outlet or voltage, or both, and bushingsinstalled at either the power inlet or the power outlet, or both, so as to reduce the size of the gas insulating apparatus. Specifically, the above-mentioned sensor portionsare installed in the space inside the porcelain tubethat constitutes the bushingsAs this space, it is preferable to use the space on the outer-periphery side of the electric field relaxation memberprovided inside the porcelain tube 15.

The present invention combines sensor portionsof the device for measuring either current flowing through the line from the power inlet to the power outlet or voltage, or both, and bushingsinstalled at either the power inlet or the power outlet, or both, so as to reduce the size of the gas insulating apparatus. Specifically, the above-mentioned sensor portionsare installed in the space inside the porcelain tubethat constitutes the bushings. As this space, it is preferable to use the space on the outer-periphery side of the electric field relaxation memberprovided inside the porcelain tube

Gas insulated device and failure rating method

A gas insulated switchgear capable of performing maintenance and inspection of a breaker without shutting down a bus line includes a first case containing a breaker and having a bushing for leading a load and a second case containing a plurality of disconnectors and having a plurality of bushings for leading a plurality of bus lines to be connected to the disconnectors. The first case and the second case are connected to each other through a gas partition spacer.

Gas insulated switchgear

The present invention provides a method of diagnosing a partial discharge in a gas-insulated apparatus and a partial discharge diagnosing system for carrying out the same to achieve highly accurate diagnosis through the detection of a partial discharge signal and diagnosing the partial discharge signal through multiple conditional branching. The partial discharge diagnosing system of the present invention consists: a partial discharge signal detector for detecting a partial discharge signal representing a partial discharge produced in the gas-insulated apparatus, a signal analyzer for receiving the partial discharge signal detected by the partial discharge detector and analyzing the partial discharge signal, a diagnostic unit for determining a cause of the partial discharge on the basis of results of analysis made by the signal analyzer, and a display unit for displaying results of diagnosis. The diagnostic unit is provided with a diagnostic means to make multiple conditional branching to a plurality of second diagnostic apparatus according to result of diagnosis made by a first diagnostic apparatus, and obtains a result of diagnosis made by the second diagnostic apparatus, thereby achieving highly accurate diagnosis by detecting the partial discharge signal and subjecting the partial discharge signal to multiple conditional branching.

Method of diagnosing partial discharge in gas-insulated apparatus and partial discharge diagnosing system for carrying out the same

An insulated device diagnosing system is capable of judging the deterioration, lifetime, and defects of a device. The intensity at each voltage phase angle is measured at a plurality of specific frequencies, taking high voltage phase angles as the abscissas. The deterioration, lifetime, and the kind and extent of abnormality of the device are judged from the pattern and intensity of the spectral distribution, which is obtained by peak-holding the measured intensity for a defined time period. According to the present invention, partial discharge can be measured highly sensitively and precisely to diagnose the deterioration, lifetime and the extent of defect of the device. As a result, the insulation reliability of the device can be improved, and the part of the device that should be repaired/replaced can be grasped before disassembly of the device, thereby cutting the maintenance cost.

Insulated device diagnosing system that prepares detection data from partial discharge signal such that periodic elements are given to different specific frequencies of the partial discharge signal

The present invention provides a method of diagnosing a partial discharge in a gas-insulated apparatus and a partial discharge diagnosing system for carrying out the same to achieve highly accurate diagnosis through the detection of a partial discharge signal and diagnosing the partial discharge signal through multiple conditional branching. The partial discharge diagnosing system of the present invention comprises: a partial discharge signal detector for detecting a partial discharge signal representing a partial discharge produced in the gas-insulated apparatus, a signal analyzer for receiving the partial discharge signal detected by the partial discharge detector and analyzing the partial discharge signal, a diagnostic unit for determining a cause of the partial discharge on the basis of results of analysis made by the signal analyzer, and a display unit for displaying results of diagnosis. The diagnostic unit is provided with a diagnostic means to make multiple conditional branching to a plurality of second diagnostic means according to result of diagnosis made by a first diagnostic means, and obtains a result of diagnosis made by the second diagnostic means, thereby achieving highly accurate diagnosis by detecting the partial discharge signal and subjecting the partial discharge signal to multiple conditional branching.

A bushing has a central conductor, and a plurality of internal shield rings. Gaps are formed between the shield rings such that equipotential lines extend through gaps. Electric field concentration in a tangential distribution on a part of the surface of the bushing corresponding to an upper part of an internal shield ring is relieved to prevent corona discharge under wet conditions, and antipollution performance and withstand voltage characteristics can be improved.

Bushing

In a gas insulated electric apparatus having gas sections filled with insulating gas, a locating device determines a position of a gas section in which an insulation abnormality is detected, on the basis of a detection signal from sensors disposed in each of predetermined gas sections. At the same time a hindering degree diagnosing device diagnoses the degree and the kind of the insulation abnormality, by comparing a detection signal from the sensors with data stored in a data base. A valve control generates a valve control signal, responding to the locating device and the hindering degree diagnosing device, and in response to the valve control signal, a trip circuit generates a valve opening signal to open an electromagnetic valve disposed in a gas section in which an insulation abnormality is detected. An insulating gas injecting and evacuating device injects an insulating gas, different from the initial insulating gas with which the gas sections are filled beforehand, into the gas section for which the electromagnetic valve has been opened by the valve opening signal, or evacuates a predetermined amount of the insulating gas with which the gas sections are filled beforehand, so as to increase insulation strength.

Gas insulated electric apparatus

A gas insulated switchgear has a container which is filled with an insulating gas, a conductor disposed with the container, an insulator for supporting the conductor. An outer periphery of the insulator is made smooth so as to improve a dielectric strength of the device. The insulator is made of an organic substance base and an inorganic material filler added to the base. In order to improve the dielectric strength, the filler is atomised or the insulator is coated.

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Hitachi, Japan

Fumihiro Endo