TRANSMISSION-LINE INSTALLATION

Submitted by :

Jonathan V. RebanalKenneth Llaneta

Clint Mark Logronio

Dan Ray Tria

Location- when transmission line is contemplated, the first thing that should receive careful thought is the question of the best location of the line.

In many cases the immediate requirement of transmission line merely to supply a particular load from a particular plant. The particular route that the line should follow will depend on the following.1. possible future markets for power.2. suitable and economic right of way.3. favorable climatic conditions.

In many cases it will be profitable to outline a longer route for the line, so as to take in a few towns or localities where future demands for power can easily be met. The most Suitable and economic right of way is independent on a very large number of items, a few of which are named below:1. TOPOGRAPHY2. ACCESSIBILTY3. COST OF RIGHT OF WAY

It is often necessary to take a round-about route in order t avoid swamps or hilly country. Construction through swamps is not only difficult but also costly. Handling of construction materials is serious problem in very hilly country. As a general rule very long spans are objectionable, because they involve special towers, cables, and fittings, but in many cases it becomes necessary to use them, as in crossing a river, a body of water, or a deep valley.

Accessibility of a line is very important, not only during construction but also for possible repairs of patrolling.

SYSTEM TRANSMISSION- because of economical reactions, three-phase circuits are generally used for transmission of electrical power; hence the treatment given in this chapter, as well as that given in chap.

Transmission lines may conveniently be classified in the following manner:1. SINGLE LINE2. PARALLEL LINES3. RADIAL LINES4. RING SYSTEM5. NETWORK

The simplest form is the single line, such as obtained from a power plant supplying its entire output to ne load center over a single circuit line.Such a system has a disadvantage that in case of damage to the line the service is in interrupted. its use is more or less confined to small power systems and is therefore becoming more and more uncommon.

LINE SUPPORTS- electrical power may be transmitted by overhead or underground conductors. Under ground transmission , with exception of a few notable cases, is limited to voltages less than 45,000 volts and hence, will be considered under the general subject of distribution in chap. The supports for overhead transmission lines may be any of the following class:Poles…………………………………............................ Wood Steel

Towers……………………………………………Flexible Suspension Dead End

There are a number of ways in which wood poles are used, the simplest being a single pole with cross arms carrying the insulators.

For two circuits it is often necessary to use two or three crossarms. A large number of bracing methods are used to strengthen pole lines, particularly at the corners or bends, or when under dead end stress; one common method known as a frame.

Electric power is the rate at which electric energy is transferred by an electric circuit. The SI unit of power is the watt, one joule per second.Electric power is usually produced by electric generators, but can also be supplied by chemical sources such as electric batteries. Electric power is generally supplied to businesses and homes by the electric power industry.

There is a great variety of steel poles on the market from which a proper choice for a particular installation can be made. They may be a tabular form iron, laticced steel construction, or expanded H sections, the laticced type and expanded H sections being the most common. Each installation being more or less a problem of its own, but in general three classes may be recognized.

Double-circuit strain towerAngle tower

Steel-pole line Double circuit pole line

Single circuit line Double circuit suspension tower

Typical flexible towerErecting a tower in halves

Method of erecting steel tower

Transmission Line Tower for providence river crossing.

Transposition Tower

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