There are so many important features and items of high tension transmission lines and we have already discussed some of them in our previous articles. Today we are a plan to discuss some of the important parts of high tension transmission lines. In here we are a plan to discuss some important feature of line insulators, Shield wires and impact of line connectors and vibration damper of overhead lines.
Line insulators of high tension transmission lines
If existing Insulators are in good functional condition and are adequate for use at the higher voltage, the need for their replacement may hinge on their mechanical strength, especially if the line is to be reconnected with a larger conductor.
Since the mechanical rating of suspension insulators are a function of the Conductor tension, reconnect with a heavier conductor may require replacement of the existing insulators with a higher rating Insulators.
In such cases, there may also be a requirement to replace Single I suspension String with a Double I or a V insulator string.
Further, in order to reduce sag, replacement of conductor may be followed by increases in the everyday tension limits. This places added tension stress on Insulators on a dead-end and heavy angle structures and may require replacement with insulation of higher mechanical rating.
Use of insulated cross arms of polymer insulator’ may also be required for achieving necessary compaction.
Shield Wires of Transmission Line
Shield wires can be a significant part of the structural loading. Tension, vertical, and transverse loads from shield wires occur at the top of the structure.
Due to the attachment of earth wire at the peak of the tower structure, even modest loads on the earth wire can result in large overturning moments on the structure. Therefore, in situations where additional shield wire has been provided or wire diameter has been increased, it may be necessary to respectively strengthen the tower peaks.
Line connectors and hardware will be replaced as part of any reconductoring. when new conductors are bundled with old conductors, the hardware would need to be replaced, but original connectors may be left in place if in good condition.
Vibration dampers of high voltage transmission lines
Any existing vibration dampers should also be replaced and, if the original conductor is re-tensioned to provide additional ground clearance, the entire vibration damping control system should be reviewed and upgraded.