Electric power transmission is the bulk transfer of electrical energy from generating power plants to high voltage substations. High voltage transmission lines, when interconnected, become the transmission networks, typically referred to as the power grid.
Electricity is transmitted at high voltages to reduce the amount of energy lost in long distance transmission. Power is usually transmitted through overhead power lines although underground transmission lines are sometimes used. High voltage transmission lines are made up of either copper or aluminum conducting lines suspended by towers.
Most transmission lines use high voltage three-phase alternating current (AC). High voltage direct current (HVDC) technology can be used to improve efficiency over extremely long distances.
Towers for the support of the lines can be made of wood, steel, concrete, aluminum or occasionally, reinforced plastics. Bare wire conductors on the line are usually made of aluminum, though some copper wires are used in medium voltage distribution and low voltage connections to consumers.
One primary function of overhead power line design is to give adequate clearance between energized conductors and the ground, preventing dangerous contact with the line, and to provide reliable support for the conductors, which can be subject to storms, ice, earthquakes and other potential causes of damage.
Overhead transmission lines are classified by their range of voltage:
-Low voltage, less than 1000 volts, used for connection between a residential or small commercial customer and the utility.
-Medium Voltage (Distribution), between 1000 volts (1kV) and approximately 69kV, used for distribution in urban and rural areas.
-High Voltage, above 69kV to 345kV used for sub-transmission and transmission of bulk quantities of electric power and connection to very large consumers.
-Extra High Voltage (transmission), above 345kV up to about 800kV, used for long distance, very high power transmission.
-Ultra High Voltage, higher than 800kV.
High-voltage lines are often carried on lattice-type steel towers or pylons. In remote areas, aluminum towers may be placed by helicopters. Concrete poles have also been used. Poles made of reinforced plastics are also available but their high cost restricts application.
EPC companies accept total responsibility for all engineering, procurement and construction activities. EPC projects are handled in-house � from initial design, procurement of all materials, and completion of construction. This approach offers a single point of contact for a project from start to finish.
Beta assigns a dedicated point of contact, the project manager, for each project. The project manager coordinates the engineering, procurement and construction of a project. This streamlined project execution ensures each project follows a fast-track schedule and offers economical solutions.
EPC projects allow the staff in the engineering, procurement and construction areas to coordinate the purchase and delivery of materials so that equipment is delivered on site at the right time. Quality inspections can be completed on site when equipment is received.
Advantages of using an EPC Company:
�Firm price/price certainty
�Economical solutions
�Fast-track schedule
�Single point of responsibility
�Avoid risk of scope voids or overlaps
�Avoid contract disputes
�Avoid coordination problems
