VISCAS Corporation

United States

VISCAS Corporation

United States
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Kagoura T.,Telecommunications and Energy Laboratories | Kimura A.,Underground Power | Tateno Y.,VISCAS Corporation
Furukawa Review | Year: 2016

In the Fukushima Floating Offshore Wind Farm Demonstration Project (Fukushima FORWARD Project), which is a commissioned business from Ministry of Economy, Trade and Industry, Furukawa Electric (FEC) is in charge of a power cable transmission system. FEC have designed a riser cable which has been connected to the world's largest 7 MW class floating offshore wind turbine generator. Pursuant to the completion of the project, we are issuing this report.


Kon H.,VISCAS Corporation
Proceedings of the International Symposium on Electrical Insulating Materials | Year: 2011

VISCAS, which is a joint company of Furukawa electric co. and Fujikura Ltd. since 2001, provides several kinds of components and technologies for power transmission system such as power cable and accessories (joint and termination) including installation, diagnostic method (PD measurement, loss-current measurement and residual-charge measurement) to all of world. To supply high reliable components to worldwide customers, we also have made efforts to improve their performances by research activities. © 2011 The Institute of Electrical Engineers, Japan.


Ide K.,Tokyo Electric Power Company | Nakade M.,Tokyo Electric Power Company | Takahashi T.,VISCAS Corporation | Nakajima T.,VISCAS Corporation
Electrical Engineering in Japan (English translation of Denki Gakkai Ronbunshi) | Year: 2012

Much of oil-filled (OF) cable has been used for a long time as 66- to 500-kV extrahigh-voltage cable. Sometimes we can see extremely degraded tan δ oil (several tens of percent of tan δ, for example) in joint boxes, etc. The values of tan δ calculated by a simple combination model of paper/oil show that the oil-impregnated paper with such a high tan δ oil likewise has an extremely high tan δ, which must result in thermal breakdown. However, such an event has not taken place up to the present in actually operated transmission lines. This fact suggests that some mechanism for the suppression of tan δ has acted in the paper insulation impregnated with degraded tan δ oil. Therefore, we investigated in detail the tan δ characteristics of paper impregnated with extremely high tan δ oil. In addition, based on the investigation results, we developed a method for simulation of heat generation by dielectric loss in an OF cable joint (which has degraded tan δ oil). Copyright © 2011 Wiley Periodicals, Inc.


Harada H.,Tokyo City University | Hayashi N.,Tokyo City University | Tanaka Y.,Tokyo City University | Maeno T.,Tokyo Institute of Technology | And 2 more authors.
IEEJ Transactions on Fundamentals and Materials | Year: 2011

We have observed space charge profiles in cross-linked polyethylene (XLPE) under dc high electric field using the PEA (pulsed electro-acoustic) system to study the relationship between space charge behavior and dielectric breakdown. In our previous research work, we have found that a large amount of, so called, packet-like charge generates in low density polyethylene (LDPE) under high dc electric field of more than 100 kV/mm. The packet-like charge enhances the electric field locally in bulk of the sample, and then finally it leads a breakdown. On the other hand, a new type of XLPE which was made through adding conductive inorganic fillers, shows a good dc dielectric breakdown characteristic and high volume resistivity under dc stress. In this report, we tried to observe the space charge behavior under high dc electric field in this material. From the results, it is found that the charge injection is effectively suppressed by adding only a small amount of conductive inorganic fillers to XLPE. © 2011 The Institute of Electrical Engineers of Japan.


Tanaka Y.,Tokyo City University | Kodera R.,Tokyo City University | Kato T.,Tokyo City University | Miyake H.,Tokyo City University | And 2 more authors.
Annual Report - Conference on Electrical Insulation and Dielectric Phenomena, CEIDP | Year: 2015

Space charge accumulation behaviors at voltage polarity reversal in cross-linked polyethylene (XLPE) and in improved XLPE for dc cable are observed using pulsed electro-acoustic (PEA) method. A huge amount of so called a packet like charge, which was enough to enhance the electric field significantly, is generated in XLPE at the polarity reversal, while it is not observed in the improved XLPE. It enhanced the electric stress locally in the sample by almost twice of the applied average stress. Since the packet-like charge was not observed in the improved XLPE at the polarity reversal, it is applicable to high voltage direct current (HVDC) network using line commutate converter (LCC) system, in which the voltage polarity reversal is necessary to inverse the current flow. © 2015 IEEE.


Nakade M.,Tokyo Electric Power Company | Nagata K.,Tokyo Electric Power Company | Kato E.,VISCAS Corporation | Tateno Y.,VISCAS Corporation
IEEJ Transactions on Power and Energy | Year: 2015

Much of oil filled (OF) cable has been used for a long time for 66 to 500 kV extra high voltage cable. Sometimes we can see extremely degraded oil (several tens % of tan δ, for example) in joint box etc, but even with that sever situation, an event such as thermal breakdown has not taken place up to the present in actually operated transmission lines. The authors have reported the tan δ characteristics of oil impregnated paper with extremely high tan δ oil and the development of a simulation method of heat generation by dielectric loss in OF cable joint. In addition to that, the degradation characteristics of actual OF cable system have been investigated. The degraded oil distribution in actual cable system seems to be balance in nearly 27 yeas. The temperature rise of joint box is quite small even with the extremely degraded oil (tan δ = 204%). With the experimental results, the OF cable system tan δ distribution is estimated and the possibility of unexpected heat generation in cable which has been installed in the conduit pipe section is proposed. © 2015 The Institute of Electrical Engineers of Japan.


Patent
Viscas Corporation, Furukawa Electric Group and Fujikura Ltd | Date: 2010-10-05

A power cable termination for aerial connection houses an end of a power cable and a conductor extension rod connected to an end of a conductor of the cable in a bushing. The bushing is filled with an insulating filler. The insulating filler is composed of any one of: (1) a mixture of a silicone oil and a silicone rubber; (2) a mixture of a silicone oil and a silicone gel; and (3) a mixture of silicone oil, a silicone rubber and a silicone gel.


Patent
Furukawa Electric Group and Viscas Corporation | Date: 2016-08-03

Protrusion portions (35a) and recess portions (35b) are formed on a metal layer (31). The protrusion portions (35a) are repeatedly formed in a lattice shape at a pitch of P. Similarly, the recess portions (35b) are repeatedly formed in the lattice shape at the pitch of P. The protrusion portions (35a) and the recess portions (35b) are arranged in the same arrangement direction and arranged shifted to each other by half the pitch in the arrangement direction. The protrusion portions (35a) and the recess portions (35b) are formed independently of each other without contacting each other. In order to allow a multilayer tape (30) to reliably follow the bending deformations of a power cable (13) (submarine cable (3)) in all directions, in an arbitrary cross-section taken in the longitudinal direction of the multilayer tape (30) (in the axial direction of an impermeable layer (21)), the protrusion portions (35a) or the recess portions (35b) are necessarily arranged at predetermined intervals.


Patent
Viscas Corporation, Electric Power Development Co. and Fujikura Ltd | Date: 2016-11-23

A method of connecting return conductors of power direct-current coaxial cables each including a main conductor at the center of the cable, a main insulating layer around the main conductor, and a return conductor that is formed by coaxially stranding a plurality of return-conductor wires around the main insulating layer includes forming a return-conductor wire bundle by placing a plurality of return-conductor wires next to each other for each of the power direct-current coaxial cables and welding return-conductor wire bundles of the power direct-current coaxial cables in a butt jointing manner.


Patent
Furukawa Electric Group and Viscas Corporation | Date: 2016-02-05

Protrusion portions and recess portions are formed on a metal layer. The protrusion portions are repeatedly formed in a lattice shape at a pitch of P. Similarly, the recess portions are repeatedly formed in the lattice shape at the pitch of P. The protrusion portions and the recess portions are arranged in the same arrangement direction and arranged shifted to each other by half the pitch in the arrangement direction. The protrusion portions and the recess portions are formed independently of each other without contacting each other. In order to allow a multilayer tape to reliably follow the bending deformations of a power cable (submarine cable) in all directions, in an arbitrary cross-section taken in the longitudinal direction of the multilayer tape (in the axial direction of an impermeable layer), the protrusion portions or the recess portions are necessarily arranged at predetermined intervals.

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