TRANSMISSION LINES DESIGN and ELECTRICAL ENGINEERING HUB

The composite fiber optic overhead ground wire shall be made up of buffered flexible glass optical telecommunications fibers contained in a protective central fiber optic unit surrounded by concentric-lay stranded metallic wires in single or multiple layers. The dual purpose of the composite cable is to provide the electrical and physical characteristics of conventional overhead ground wire while providing the optical transmission properties of optical fiber. Stranded metallic wires a) The basic construction shall have bare concentric-lay stranded metallic wires with the outer layer having left hand lay unless otherwise specified by the purchaser. b) The stranded wires may be of multiple layers with a combination of various metallic wires within each layer. The direction of lay shall be reversed in successive layers. c) The wires shall be so stranded that when the complete OPGW is cut, the individual wires can be readily regrouped and then h...

GIL offers several advantages for high capacity power transmission, as listed below. Low Transmission Losses   Resistive losses are low because of the large cross-section of the conductor and enclosure pipes. Typical GIL resistances are 6–8 m /km depending on the outer diameter (500 mm or 600 mm) and the wall thickness of the enclosure and conductor pipe (6 mm to 15 mm).  The transmission losses are related to the square of the transmitted current as Pv = I2 · R (I = current, R = resistance). When the current rating is high – as it is for GIL (e.g., 3000 A) – then the effect of low transmission losses is high. The losses through the insulating gas are negligibly small. Low Capacitive Load   Electric phase-angle compensation is only needed at very long lengths, because the capacity of the GIL is low, typically 55 μF/km. Therefore, no or low compensation coils are needed under most network conditions for transmission ...

Electrical specifications for buildings or projects are written legal descriptions of the work to be performed by the electrical contractor, subcontractors, and electric power utilities and the responsibilities and duties of the architect/engineer, general contractor, and owner. Electrical specifications and electrical drawings are integral parts of the contract requirements for the performance of electrical work. Because specifications are a significant part of a legally binding contract, typically involving expenditures of thousands or even millions of dollars, it is important that they be mutually compatible with the drawings and as free as possible of errors or discrepancies. It has long been known that even minor errors in wording or intent or the presentation of incorrect data or measurements can result in expensive repairs or replacements of hardware, lost time in the completion of the schedule, and serious project cost overru...