TRANSMISSION SYSTEM REQUIREMENTS

Transmission System Requirements

Listed below are the typical points to be considered before starting or even operating an Electrical Power System. These factors can be best categorized into three main points; Electrical Design, Mechanical Design & Structural Design.

Electrical Design of AC system involves;

power flow requirements
system stability and dynamic performance
selection of voltage level
voltage and reactive power flow control
conductor selection
losses
corona-related performance(radio, audible, and television noise)
electromagnetic field effects
insulation and over voltage design
switching arrangements
circuit-breaker duties
protective relaying

Mechanical Design includes

Sag and tension calculations
conductor composition
conductor spacing (minimum spacing to be determined under electrical design)
types of insulators
selection of conductor hardware

Structural Design

selection of the type of structures to be used
mechanical loading calculations
foundations
guys and anchors.

Miscellaneous features

line location
acquisition of right-of-way
profiling
locating structures
inductive coordination (considers line location and electrical calculations)
means of communication
seismic factors

REFERENCE : Standard Handbook for Electrical Engineers by Donald G. Fink and H.Wayne Beaty

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PARTS OF A POWER TRANSFORMER

What are the name of the basic parts of a Power Transformer? We can not deny the fact that only a handful of electrical engineering students are presently familiar with power transformers especially on what it looks like. Unlike a transformer we found in our homes, a power transformer’s appearance and construction is somewhat more complicated. It is not just a simple winding with a primary and secondary terminal although basically any transformer has one. The function that a power transformer plays in an electrical system is very important that an electric utility can not afford to loss it during its operation. Our discussion here will focus more on the basic parts and functions of a power transformer that are usually tangible whenever you go to a substation . Although not all power transformers are identical, nonetheless they all have the following listed parts in which the way of construction may differ.

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ELECTRIC MOTOR FRAME SIZE STANDARD SPECIFICATIONS

ELECTRIC MOTOR FRAME SIZE STANDARD SPECIFICATIONS How is electric motor frame size being specified? Motor frame dimensions have been standardized with a uniform frame size numbering system. This system was developed by NEMA and specific frame sizes have been assigned to standard motor ratings based on enclosure, horsepower and speed. The current standardized frames for integral horsepower induction motors ranges from 143T to 445T. These standards cover most motors in the range of one through two hundred horsepower. Typical example of where you can locate the frame is shown in Fig 1.2.D – Frame No. The numbers used to designate frame sizes have specific meanings based on the physical size of the motor. Some digits are related to the motor shaft height and the remaining digit or digits relate to the length of the motor. The rerate, or frame size reduction programs were brought about by advancements in motor technology relating mainly to higher temperature ratings of insulating mate

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ELECTRIC MOTOR NAMEPLATE SPECIFICATIONS

How do we interpret an electric motor nameplate? Motor standards are established on a country by country basis.Fortunately though, the standards can be grouped into two major categories: NEMA and IEC (and its derivatives). In North America, the National Electric Manufacturers Association (NEMA) sets motor standards, including what should go on the nameplate (NEMA Standard MG 1-10.40 "Nameplate Marking for Medium Single-Phase and Polyphase Induction Motors").

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