Mr. Phan Dinh Hoa - Director of EVNPSC said: The generating units of Hoa Binh Hydropower Plant have been operated for more than 30 years, 220kV oil-filled cable system serves to transmit the generating capacity of the units from booster transformers to the 220kV transmission substation that has begun to "get outdated", there is a risk of an incident leading to the shutdown of the units.
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Some dry cable information to be replaced:
- Voltage level: 220kV
- Number of circuits: 01 unit circuit
- Start point: 220kV output of booster transformer of Unit 1
- End point: Location of connection to the overhead line at the transmission substation of the plant
- Single line length: About 600 meters, weight 11 tons
- Cable type: Single core copper cable, cross section of 800 mm2 XLPE insulation, equipped with fiber optic cable in 1 phase of each circuit for connection to cable temperature controlling DTS system.
- Installation: Cable mounted on a rack with 1,620 brackets.
- Cable rack is made of galvanized steel, bolted connection appropriate with installation location.
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Following the direction of the Board of Members and the General Director of EVN on replacing oil-filled cables with dry cables of the project, this is the first replacement of oil-filled cables with dry cables in a hydroelectric power plant in Vietnam. Therefore, EVNPSC has mobilized the most elite force to research, understand, know well about the construction plan and closely coordinate with experts in the implementation process. Up to now, the progress of the project is following up the plan and the project is under control.
After successfully testing the replacement of dry cable for generating unit 1 and is expected to have generating unit 2 at the end of 2021, EVN and EVNPSC will evaluate and summarize experiences and analyze advantages and disadvantages to replace cables for other units of Hoa Binh Hydropower Plant in the coming years.
Dry cable is a new technology, which shows the advantages of compactness, simpler installation, higher quality and longer service life, and is more resistant to the impact of the natural environment at higher temperatures than oil-filled cables. However, the construction of dry cable line is a new work in Vietnam, especially the replacement and repair work will be much more difficult than the new construction. The constructed cablelines are located in the technical tunnel of the plant. The implementation plan and construction conditions are very difficult when the generating units and the equipment are in operation. In particular, in the tunnel, the average temperature is over 40 degrees Celsius, sometimes up to nearly 50 degrees Celsius when the outdoor temperature is high and the impact from the operation of the generating units.
Some pictures evn.com.vn recorded in the evening of 2 May:
Some pictures evn.com.vn recorded in the evening of 2 May
EVNPSC engineers checking cables during cable pulling
Cable No. 3 is also the last cable of unit 1 of Hoa Binh hydropower plant, which is gradually being put into position
Hoa Binh hydropower cable tunnel
Leaders of EVNPSC Trade Union giving gifts to encourage engineers and construction workers.