25-year operation of North-South 500kV high-voltage transmission line

After 25 years in operation, the 500kV North-South super high-voltage transmission line circuit 1 has been the “string” connecting the power system in both directions, improving the safety of power supply and power quality for the national power system. The project also shows a beyond-the-era vision, which is a historic turning point of Vietnam’s Power sector.

Daring ideas, drastic breakthroughs

In the early 1990s, the Southern region was in a serious power shortage, 1 day supply, then 2-3 days in outage. How to make the South not “hungry” for power, ensure successful implementation of the program on socio-economic innovation and development is the concern by the Party and State leaders at that time.

Engineer Tran Viet Ngai - Deputy Head of the Management Board for the 500kV transmission line and an experienced manager, in charge of the construction of the most “difficult” section of the work, recalled: On Lunar New Year in 1991, Prime Minister Vo Van Kiet met leaders of the Ministry of Energy and electricity construction companies. A question raised by The Prime Minister that there was power shortage in the South while it was redundant in the North, the Ministry of Energy was requested to find a way to supply power from the North to the South.

Receiving the direction of the Prime Minister, Minister of Energy Vu Ngoc Hai immediately directed the related agencies, branches to implement necessary procedures for urgently constructing the 500kV super high-voltage transmission line to supply power from the North to the South in a shortest time. This is the first time Vietnam has constructed a 500kV super high-voltage transmission line with length of about 1,500km. At that time, in the world, the longest one was only 700-800km and the construction time lasted 7-8 years.

A corner of construction site for North-South 500kV transmission line - Documentary photo

Among various options, the line running along Truong Son mountain range is the most optimal one. The Ministry of Energy invited Project Performance International (PPI) (Australia) as the consultancy unit for this project. At the same time, the Steering Committee and the Management Board for the construction of the transmission line were established.

All works were very urgently prepared and good results were gained. The Minister reported to the Prime Minister for approval of the construction implementation. Under the direction of the Prime Minister, the project was only allowed to be constructed within 2 years because of serious power shortage in the South.

When the guideline was announced, some senior officials and scientists were still skeptical, because of many technical difficulties such as wavelength, voltage at the end of the line, labor safety in construction of a too long line, extremely dangerous topography with full of obstacles and difficulties in many places, etc. However, with great determination, close direction of the Prime Minister and the tireless effort by  staffs and employees of the Ministry of Energy, the project was successfully completed after 2 years of design and construction at the same time.

How to construct and complete within 2 years?

In order to construct the North-South 500kV super-high-voltage transmission line, various solutions were set out in detail, in which, preparing the construction progress, arranging personnel from design survey, construction, supervision, capital arrangement, contract signing, procurement of equipment and materials are strictly and reasonably implemented with a spirit of urgency.

The project was divided into 4 sections of construction, each of them was undertaken by an electricity construction company. Of the four sections, the most difficult part was the second one, running from Ha Tinh to Kon Tum with a length of over 600km, including about 400km of hills, jungles and many complicated rivers and stream, etc., undertaken by Electricity Construction Company No. 3. In many briefings, considering construction progress, Prime Minister Vo Van Kiet said that “If the section constructed by Electricity Construction Company No. 3 is completed, the whole transmission line will be completed.”

Sharing about the decisive factors to ensure the set construction schedule of 2 years, Mr. Ngai said: The total labour force on the whole construction site was mobilized with the employment of regular staffs and employees (officials, engineers and skilled workers) combining with local residents, soldiers, police, enterprises, etc., to do all works to realize the target of ensuring the set progress.

An equally crucial factor, contributing to ensuring the construction progress, was the timely encouragement, rewarding, reasonable labor organization such as: Contracting work for each group, team, enterprise, combining regular, local and other requisitioned labour forces. For 2 years, regardless of day and night, Sunday, holidays, rain, storm, flood, frozen weather or flaming sunshine, they all strived and made all efforts to complete the project on schedule with high quality.

In order to solve the capital for this important project, the Project Management Board regularly worked with departments of the Ministry of Energy, the Ministry of Finance, and the State Treasury, creating a favourable mechanism for adequate and timely allocation of capital. Every week, the Ministry of Energy organized briefings and inspection on the construction progress, promptly removing difficulties in construction, particularly, there were many meetings directly attended and directed by the Prime Minister for timely and absolutely handling all difficulties and obstacles arising during the construction.

On 27th May 1992, the Prime Minister decided to commence placing foundations in three locations of Man Duc (Hoa Binh), Hoa Son - Hoa Vang (Da Nang) and Phu Lam. After nearly a year of constructing, placing foundations on the entire transmission line was completed. The smallest foundation was in about 300m3 of concrete (supporting pillar), that of anchor pillar was in average of 1,000 - 1,500m3 concrete, depending on the type of pillar, that of crossing pillar was in higher concrete volume. The soil and rock excavation was completed with tens of millions of cubic meters.

Thanks to the people’s consent and support, drastic direction by the Prime Minister, urgent implementation of ground compensation and clearance of the Ministry of Energy, all difficulties and problems were resolved, the construction was ensured on schedule.

In March 1993, the erection of pillars (about 3,600 ones) across the line was  successfully completed. The pulling of transmission line, installation of fiber optic cables, porcelain sets, accessories was completed at the end of March and early April in 1994. It was followed by the work of testing, adjusting and inspecting by the National Load Dispatch Authority, preparing to energize power, connecting to the grid at Da Nang substation on 27th May 1994 - making a crucial mark in the development history of Vietnam’s Power sector.

Some information about the North-South 500kV transmission line (circuit 1):

- Commencement date: April 1992

- Power generation date: May 1994

- Main construction volume:

- Installing and erecting 3,600 steel pillars, equivalent to 60,000 tons of electric poles;

- Pulling 1,487km of wires and lightning conductors, equivalent to 23,000 tons of conductors and 930 tons of lightning conductors;

- Constructing 22 fiber optic repeating stations, 19 lines operating points;

- Placing 280,000m3 of concrete foundation with 23,000 tons of reinforcement; 6,300 tons of insulating porcelain.

- Hundreds of billions of kWh from the North and Central to the South have been transmitted, contributing to ensuring power supply for the South. 

  • 19/04/2019 04:44
  • evn.com.vn