How is sag overhead line calculated?
How is sag overhead line calculated?
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.
How do you calculate 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 the formula of sag in transmission line?
The maximum dip (sag) is represented by the value of y at either of the supports A and B.At support A, x = l/2 and y = S. (ii) When supports are at unequal levels: In hilly areas, we generally come across conductors suspended between supports at unequal levels.
What is SAG and its formula?
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. The calculation of sag and tension in a transmission line depends on the span of the overhead conductor.
What is SAG template?
A sag template is a tool in spotting manually the position of towers or poles on the route profile. Today, transmission design engineers are using sophisticated design softwares. A sag template is specific for the particular line voltage, the conductor used and local weather conditions.
What is SAG limit?
Higher sag means loose conductor and lower tension. Therefore, a suitable value of sag is calculated so that the conductor remains in safe tension limit keeping the sag minimum. The tension at any point on the conductor acts tangentially. Therefore, the tension at the lowermost point on the conductor is horizontal.
What is sag in overhead line?
Sag literally means to be bending in shape. In. overhead transmission lines, the difference in level. between points of supports (towers or utility poles) and the lowest point on the conductor is called sag.
How do you make a SAG chart?
How to make a Sag Template?
- Step 1: Gather the design data.
- Step 2: Determine the weather conditions that may affect your conductor.
- Step 3: Calculate the sag and tension of the conductor.
- Step 4: Plotting of the parabolic/catenary curve.
- Step 5: Transfer the plotted curve to a transparent paper or celluloid.
How are SAG templates prepared?
Preparation of the Sag Template Suitable scales are selected. With the help of the sharp pointed probe, the curves are then transferred to transparent celluloid or perspex. The celluloid or Perspex is then cut along the line of maximum sag, i.e., the hot curve.
What factors affects sag?
Factors Affecting Sag (i) Weight of conductor. (ii) Location of the conductor. (iii) Length of the span. (iv) Temperature.
What is SAG chart?
Stringing chart gives the data per sag to be allowed and the tension to be allowed for a particular temperature. Stringing chart prepared by calculating the sag and tension on the conductor under worst conditions such as maximum wind pressure and minimum temperature by assuming a suitable safety factor.
What is sag template?