Received: 16-01-2024 Revised: 12-02-2024 Accepted: 07-03-2024 1493 Volume 48 Issue 1 (March 2024) hps://powertechjournal.com Design and Analysis of 400KV Extra High Voltage Power Transmission Lines in Lebanon Hassan Amin Osseily Lebanese International University LIU The International University of Beirut BIU Electrical and Electronics Department Beirut Lebanon Hassan.osseily@liu.edu.lb Abstract: This paper aims to design and analyze an overhead AC extra high voltage transmission line in Lebanon, using ACSR conductors, to meet the growing demand for the future. The optimal design will consider various factors to achieve the best system efficiency and performance, while complying with regulations and safety standards, including EHV voltage level, conductor size, number of conductors per phase, cable sag, and other factors, as well as estimating and describing environmental impacts such as conductor surface potential gradient, corona loss, radio interference, and audible and random noise. Keywords: Power Transmission Lines, Corona Effect, EHV, Overhead Lines OHL I. INTRODUCTION TO POWER TRANSMISSION LINES IN LEBANON High voltage transmission allows the usage of smaller conductor sizes, which reduces the cost of the transmission line infrastructure. Furthermore, high voltage transmission also reduces the amount of current flowing through the transmission line, which leads to less heating and power loss. This is important for maintaining the stability and reliability of the power system. In addition, high voltage transmission allows for higher power transfer capability, which is essential for meeting the increasing demand for electricity in today's modern society [1]. It also enables the integration of renewable energy sources, such as wind and solar power, which are typically located in remote areas and require long-distance transmission to demand load centers. Overall, high voltage transmission plays a crucial role in the efficient and reliable delivery of electricity from power plants to consumers, helping to ensure a stable and resilient power system. Figure 1, shows the general power diagram including the transmission system [3].