Design, Supply, Erection & Commissioning of 132KV Transmission line of Monopole from Roma to Lusaka under Zesco Ltd.

Introduction

Zambia Electricity Supply Corporation (ZESCO) is a vertically integrated electricity utility, which generates, transmits, distributes, and supplies electricity in Zambia. In 2014 Lusaka Transmission and Distribution Rehabilitation project (LTDRP) under ZESCO limited, was formed to strengthen and to increase the capacity and to  improve the reliability of the electricity transmission and distribution system in the Lusaka area. The construction of the projects was courtesy a line of credit received by Government of Zambia from the International Development Association (IDA), World Bank.

Tender & Award

Zambia Electricity Supply Corporation (ZESCO) floated tender through International Competitive Bidding (ICB) and is being financed by International Development Association (IDA), World Bank. The tender was floated on 23^rd July 2017, many bidders participated in the said tendering process, out of which BEL was found to be technically and commercially competent of all the bidders. Thus, tender was awarded to BEL on 5^th March 2018.

About the Project

The Lusaka Transmission and Distribution Rehabilitation Project (LTDRP) aims to strengthen the existing transmission and distribution infrastructure in and around Zambia’s capital, Lusaka. This is achieved by, amongst other, increasing the power intake and distribution capacity and reliability of the 132 kV ring surrounding Lusaka. The ring currently connects Lusaka West - Roma -Leopards Hill - Waterworks - Coventry - Lusaka West substations. During the execution of the LTDRP packages, the integrity of the ring must be protected by avoiding the isolation of more than one section at any point in time.

Prior to constructing of the 132kV Double Circuit transmission line, there was an existing line of 132 KV Single Circuit Transmission Line on Lattice Tower, which had to dismantled and the dismantled materials to be stored at ZESCO farm/Stores. After dismantling the existing line, 132kV Double Circuit transmission line was constructed in the same servitude of the existing line, stretches for around 20.00 kM in densely populated area Lusaka i.e., from Roma Sub-station to Lusaka West Sub-station. The Transmission Line consisted of 85 monopoles.  

Due, to delay in providing the providing the shutdown of the existing Line, Execution of said project was started from 4^th November’2019, amid crucial phase when world was facing 1^st  wave of COVID surge, but We (BEL) have shown utmost dedication and continued to work towards achieving our goal even under tough circumstances and completed the project on 18^th December 2020.

Above work was divided into two portions,

• Dismantling the existing 132 KV Single Circuit Transmission Line on Lattice Tower
• Construction of 132 KV Double Circuit Transmission Line on Monopoles.

Monopole design, its validation & supply was in scope of BEL. The scope involved  manufacturing, proto assembly and type testing of each type at CPRI, Bangalore and mass production of newly adopted Planted Type Intermediate Monopoles. We had parallelly finished the dismantling of the existing line and construction of the new Double circuit Transmission Line on Monopoles within the allotted time frame, with our continuous and combined effort.

Execution of said works was completed on 17^th December 2020 to entire satisfaction of the client and same was commissioned on 18^th December 2020.

Project challenges

• The powerline was passing through densely populated Local communities within the area of Lusaka. And with every limited working space for executing the Foundation, Erection and Stringing work. 

• At the Termination point near, Lusaka Sub-station, about 5 Kms of the route was passing through Rocky Mines area with no access, where dolomite stones were found during foundation and also the landslide will be under water during the rainy season. We had laid gravel mud road along the route to overcome the access obstacle.

 

Highlights

• Most of the said transmission line passes through green belt area and densely populated & residential area. Monopoles were installed in these areas within the existing servitude of the existing Line, by using area of 2.4mtr x 2.4mtr for foundation. 

• The powerline runs along a very high-density area. Multiple service LT & HT lines, pipelines, Railway, building, boundary and fences. The line was also crossing, the country’s one of the largest National Highway (Great North Road), where we were allowed only 5 minutes Traffic break for each conductor to pass across the road. 

• We had parallelly finished the dismantling of the existing line and construction of the new Double circuit Transmission Line on Monopoles within the allotted time frame, with our continuous and combined effort. The operational acceptance certificate is enclosed.

• As the Line was passing through the high-density, green belt area and there were no non-compliance with the environment, Health safety and labours laws or any legal obligation to restore the land or damages arising out of legal liability for damage to environmental. Certificate is enclosed.