The compact power transmission technology is a new technology which is developed quickly and applied in China for recent years.

The electromagnetic environment of 750 kV single-circuit compact transmission lines are researched systematically under the guidance of environmental assessment, design and construction for 750 kV compact power transmission and transfer engineering in China.

As the parameter characteristics of compact transmission lines are quite different from those of conventional transmission lines, a study of their influence on sub-synchronous resonance (SSR), the advantages and disadvantages of some series-compensated compact transmission lines for the heat-engine plant is of practical significance.

This paper introduces the technical characteristics of compact transmission lines and their applications at home and abroad,emphatically analyzing the main technical features,project costs and operation of 500 kV compact transmission line from Luoping to Baise located at high altitudes of southern power grid of China.

Two dimensional FEM is applied to the research on the power frequency electric field around compact transmission lines,and the method to improve the precision of calculation is discussed.

This paper proposes the concept of flexible compact transmission system,which would combine technical advantages of compact transmission line and flexible AC transmission system.