Inventor
YAMAGIWA TOKIO
JP35 patents
Patents
35 patentsUS5305174AApr 19, 1994
Method of and device for protecting electrical power system
HITACHI LTD106 citations96
US5214595AMay 25, 1993
Abnormality diagnosing system and method for a high voltage power apparatus
HITACHI LTD91 citations95
US5107447AApr 21, 1992
Abnormality diagnosing system and method for a high voltage power apparatus
HITACHI LTD88 citations95
US6218627B1Apr 17, 2001
Bushing
HITACHI LTD31 citations92
US6002085ADec 14, 1999
Gas insulated switchgear
HITACHI LTD31 citations92
US5627941AMay 6, 1997
Method of configuring a neural network and a diagnosis/control system using the neural network
HITACHI LTD19 citations92
US5598509AJan 28, 1997
Method of configuring a neural network and a diagnosis/recognition system using the same
HITACHI LTD38 citations92
US5473494ADec 5, 1995
Electrical power supply system
HITACHI LTD26 citations92
US5256976AOct 26, 1993
Power apparatus and method of location of a fault in a power apparatus on the basis of attenuation coefficients of electromagnetic coefficients of fault generated electromagnetic waves
HITACHI LTD25 citations92
US6424162B1Jul 23, 2002
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
HITACHI LTD22 citations91
US5982181ANov 9, 1999
Insulated device diagnosing system for diagnosing device based upon partial discharge signal data analyzed by frequency
HITACHI LTD29 citations91
US5601735AFeb 11, 1997
Long-sized tubular grounding container unit for gas-insulated electrical device and laser welding device for manufacturing the same
HITACHI LTD28 citations91
US4975800ADec 4, 1990
Contact abnormality detecting system
HITACHI LTD35 citations90
US5699219ADec 16, 1997
Ground fault current limiter and method of limiting ground fault current
HITACHI LTD33 citations89
US5798484AAug 25, 1998
Enclosed electric conductor arrangement
HITACHI LTD17 citations79
US5253180AOct 12, 1993
Apparatus and method for diagnosis of power appliances
HITACHI LTD10 citations74
US4829256AMay 9, 1989
Insulation testing device for gas insulated apparatus
HITACHI LTD18 citations74
US4818825AApr 4, 1989
Insulating spacers for use in gas-insulated electric apparatus
HITACHI LTD9 citations74
US6063997AMay 16, 2000
Gas insulated electric apparatus
HITACHI LTD14 citations73
US5929989AJul 27, 1999
Optical pressure detection method and apparatus
HITACHI LTD15 citations73
US5231256AJul 27, 1993
Puffer type gas-insulated circuit breaker
HITACHI LTD15 citations73
US4667061AMay 19, 1987
Gas insulated apparatus with internal coated insulation layer of high dielectric constant
HITACHI LTD10 citations73
US4564721AJan 14, 1986
Gas-insulated electrical apparatus with electret for captivating conductive particles and method of removing such particles during assembly thereof
HITACHI LTD16 citations73
US4549132AOct 22, 1985
Method of testing and verifying a performance for insulation to ground of a disconnecting switch when breaking a charging current
HITACHI LTD19 citations73
US6525917B1Feb 25, 2003
Power transforming system and method
HITACHI LTD8 citations72
US6292356B1Sep 18, 2001
Gas insulation switch
HITACHI LTD6 citations72
US5124687AJun 23, 1992
Power apparatus, power transmission/distribution unit, and tripping method therefor
HITACHI LTD7 citations71
US5689088ANov 18, 1997
Gas insulated device, gas insulated switchgear, gas insulated bus line, and cable direct-coupled gas insulated switchgear
HITACHI LTD7 citations69
US6538877B2Mar 25, 2003
Gas insulation switch
HITACHI LTD1 citations61
US6373687B2Apr 16, 2002
Gas insulation switch
HITACHI LTD3 citations61
US5274205ADec 28, 1993
Gas blast, puffer type circuit breaker with improved nozzle
HITACHI LTD2 citations61
US4306274ADec 15, 1981
Disc ceramic capacitor
HITACHI LTD4 citations59
US4672150AJun 9, 1987
Conductor supporting apparatus for gas insulated equipment
HITACHI LTD1 citations52
US5410243AApr 25, 1995
Three-phase collected type optical current transformer
HITACHI LTD3 citations49
US6252763B1Jun 26, 2001
Gas-insulated electrical apparatus
HITACHI LTD1 citations45