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Power Transmission

Power transmission is realized by transmission line. The maximum transmitted power which is confirmed after comprehensive consideration on the technical, economic and other factors, is called the transmission capacity of the transmission line. Transmission capacity is generally proportional to the square of the transmission voltage. Therefore, to increase the transmission voltage is the main technical solution to realize large capacity or long-distance power transmission, and is also the benchmark of power transmission technology development.

In the course of transmission line development, the transmission voltage grade is normally increased by two times. When the power output is increased to about 4 times, a new higher voltage grade will appear. Generally, 35~220KV transmission line is called high voltage line (HV), 330~750KV(EHV) transmission line is known as extra high voltage line, and the transmission line above 750KV is known as ultra-high voltage (UHV).

Generally speaking, the larger power capacity is transmitted, the higher voltage grade will be adopted. By selecting the ultra-high voltage transmission line, we can effectively reduce line loss, cut down the unit cost of line, save the land and make full use of the line trestle. At present, the transmission line voltage grades in some Southeast Asian countries are normally 20KV, 70KV, 150KV. According to the peculiar environment together with the local requirements for transmission lines, we carefully study the local practice and adopt the measures to suit the local condition. Now through optimizing the proposal, breaking through the technical difficulties, and sticking to the discovery & renovation, we have successfully met the requirements of local national grid and created the "technologically advanced, safe and reasonable” situation of overseas transmission line projects.

According to the structure, transmission lines can be divided into overhead transmission lines and cable lines. Overhead transmission consists of tower pole, wire, insulator, line hardware, bracing wire, tower foundation and grounding device, etc, and is laid above the ground.