Technology Overview

Electricity transmission is the process of transporting power energy from generation sources (thermal power, hydropower, renewable energy) to load centers through high-voltage grid systems. It is a core infrastructure that ensures supply–demand balance and stable operation of the entire power system. Electricity is typically transmitted via overhead lines or underground cables, depending on technical and economic conditions.

Technical Characteristics

Currently, two main technologies are used: HVAC (High Voltage Alternate Current) and HVDC (High Voltage Direct Current). HVAC is the conventional technology and dominates existing grids due to its lower investment cost and simpler operation. In contrast, HVDC is suitable for transmitting large amounts of power over long distances, particularly for interregional connections or renewable energy integration.

Technology	Characteristics	Advantages	Limitations
HVAC	Conventional, widely used	Lower investment cost, simple operation	Higher losses over long distances, limited controllability
HVDC	Long-distance, high-capacity transmission	Lower losses, flexible control	High converter station costs

HVDC becomes more economical than HVAC at transmission distances of approximately 600–750 km, or from around 50 km for submarine cables.

Application in Vietnam

Vietnam’s transmission system currently relies primarily on HVAC overhead lines. Underground cables are mainly used in urban areas or special terrain conditions. In the future, HVDC is being studied, including options for system interconnection and large-scale electricity imports.