Successful installation of ERS towers in disaster hit states

Supply of continuous and reliable power will be the most important aspect of a transmission line network. But, these lines are subjected to several natural disasters like earthquake, flood, landslides and hurricanes. Power failure due to these scenarios; make a severe financial damage to consumers, utilities and the power producing units. It is necessary that these transmission line utilities take precautionary actions to avoid and reduce these disruptions.

Emergency restoration system
Emergency Restoration System (ERS) structures are a temporary solution designed to bypass the existing transmission towers of any voltage in any terrain. They will be used until the main line is restored. The entire structure can then be disassembled and reused. The structure is supported by combination of guys and can be installed without any civil foundation. Erection is made ease with the usage of Gin Pole which negates the need of heavy machineries. Use of composite insulated cross arm will reduce the crossarm load on the structure and also the clearance required for insulator swing.

Restoring transmission lines between Barh and Motihari in Bihar
ERS towers have proved to be an effective solution for immediate restoration of transmission line. One fine example of such is an abandoned 400-kV quad double circuit line between Barh and Motihari in Bihar. Supreme was given the job of restoring the line.

A few things to consider while progressively working for restoring the distorted power supply.
The double circuit line was transferred to 3 sets of ERS tower with two towers in each set thereby forming a double circuit. There was no road access to the site. Survey and even transportation of materials to site was made using country boats. Rowing the boat with tower materials was difficult as the river current was increasing as the day progress.

Secondly, the span across the river was too long and hence it was necessary for us to install a tower in the middle of the river. Fortunately, the site survey made by our team found a sand dune in the middle of the river which was effectively used to install the tower. The real challenge started at the time of installing the anchors. Soil was too soft that it was not suitable for installing any type of anchors. Modular supports were specially designed for this considering the guy angle and ease for transportation. The Long Modular Steel supports offered the large width that was necessary for connecting the guy wires and also increasing the stability of the ERS tower.

Power restoration in Odisha after the disastrous Fani cyclone

Complete restoration of transmission lines in western Maharashtra
With the success of already completed projects, we undertook our 5th project where we bypassed a 220kV D/C line in Maharashtra. Highway construction between Wardha and Nagpur was stopped due to 220kV D/C line crossing the highway near Wardha. The bottom conductors of this double circuit line were too low that the required ground clearance was not available. Upon request to Maharashtra State Electricity Transmission Company Ltd. (MSETCL), it was decided to construct two new 220kV D/C towers with an increased height of 53m in order to get the required clearance. But construction of those two new towers was not possible as the towers were on the existing 220kV line route. Providing shutdown for several days to facilitate the new tower construction was beyond consideration as the line was serving most of the western part of Maharashtra.

Supreme was then approached by an O&M operator to provide our bypass arrangement with our ERS towers until their new towers are installed. After site survey, 3 locations were identified for installing the ERS towers. After getting prior approval from MSETCL, Erection works begun on 29th July, 2019. But the works were interrupted by the continuous heavy rain in the region. Site was continuously flooded by the heavy rain.

Still the determination and dedication of Supreme’s team to finish the line made it possible to complete the tower erection. The Double circuit line was successfully charged on 21st August 2019. MSETCL authorities were present at the time of bypassing the line from existing tower to the ERS tower. They provided a huge amount of appreciation for the work that has been done on completing this project.

For more details, contact:
barua@supreme.in
www.supreme.in