How is SAG calculated on a transmission line?
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How is SAG calculated on a transmission line?
Calculation of Sag:
- Case1: When the conductor supports are at equal level.
- Sag = WL2/8T.
- Case2: When the conductor supports are at unequal level.
- Sag = WtL2/2T.
What is sag in transmission line?
In a transmission line, sag is defined as the vertical difference in level between points of support (most commonly transmission towers) and the lowest point of the conductor. In the above overhead conductor AOB, S is the sag when measured vertically.
How is SAG percentage calculated?
To calculate your sag percentage, divide the static travel by the total length of the shock and multiply by 100. Most manufacturers recommend that you set your sag somewhere between 25 to 35 percent.
What is the formula for SAG?
where L = Equivalent span in meters. As in the case of conductor, the tensions at 0°C (No-wind & full wind Condition), 32″C full wind conditions and 75°C no-wind condition are determined. Sag = [WLA2 / 8TA] where LA = Actual span.
What is sag in power system?
A voltage sag (U.S. English) or voltage dip (British English) is a short duration reduction in rms voltage which can be caused by a short circuit, overload, or starting of electric motors. A voltage sag happens when the rms voltage decreases between 10 and 90 percent of nominal voltage for one-half cycle to one minute.
What is sag in catenary?
Conveyor belt sag, also known as catenary sag, refers to the tensionless section of the belt that hangs down on the return side (or underside) of the conveyor. It allows gravity to give the belt the exact amount of tension instead of relying on a mechanical take-up or tension system.
How do you calculate the SAG of a transmission line?
For getting Sag, put x = L/2 in equation (1) Sag = WL 2/8T. Case2: When the conductor supports are at unequal level. In hilly area, the supports for overhead transmission line conductor do not remain at the same level.
Why is SAG required in transmission line suspension?
Sag is mandatory in transmission line conductor suspension. The conductors are attached between two supports with the perfect value of sag. This is because it protects the conductor from excessive tension. In order to permit a safe level of tension in the conductor, conductors are not fully stretched; rather they are allowed to have sagged.
What is the relation between tension and conductor sag?
Thus if T is the tension at the support B, then T = TO. This is an important consideration in the mechanical design of overhead lines. The conductor sag should be kept to a minimum in order to reduce the conductor material required and to avoid extra pole height for sufficient clearance above ground level.
What is the tension in overhead transmission line?
The tension is generally decided by many factors like wind speed, ice loading, temperature variations etc. Normally the tension in conductor is kept one half of the ultimate tensile strength of the conductor and therefore safety factor for the conductor is 2. Now, we will calculate the Sag in an overhead transmission line for two cases.