The project is invested by the National Power Transmission Corporation (EVNNPT), managed by NPTPMB, surveyed and designed by Power Engineering Consulting Joint Stock Company No.1, and will be taken over by Power Transmission Company No.1 for operation.
Construction of 1.1km long Red River crossing section
The project has a total investment cost of nearly VND 358 billion, being implemented on the existing Son La - Viet Tri 220kV transmission line passing through Son La and Phu Tho provinces with a length of about 167km. This is the first transmission line project being managed by NPTPMB and it has been constructed since March 30, 2022.
The project includes the replacement of the existing ACSR 400/52 steel-cored aluminum cable with a composite core superheater cable having an aluminum cross-section of 421mm2, particularly the 1.1km long Red River crossing section uses a composite core superheater cable to enhance the 524mm2 aluminum cross-section.
The support chain will reuse existing insulations and non-live part fittings, replacing the live part fittings and support locks to match the substituted superheater cable. Particularly for the crossings of roads, railways, residential areas, etc., the existing single-supported insulator chains will be replaced with ceramic or glass double-supported insulator chains having load equivalent to the existing ones.
Mr. Vo Luong Nhan – Deputy Director of NPTPMB (right) giving gifts to encourage construction forces working throughout Tet
Replacing all vibration dampers to match the substituted superheater cables. Re-tensioning lightning protection wire and fiber optic cable to ensure the distance from the conductor after replacement. Raising the height of 4 towers with a 3-meter foot for towers having substandard ground phase distance. The remaining positions use the existing towers. Renovating foundations of 4 positions to suit the heightened towers. The remaining positions use the existing foundations.
As for Viet Tri 220kV substation and Son La 220kV substation, current transformers with a rated current of 1200A at the 2 compartments of Son La - Viet Tri 220kV transmission line and at compartment 200 of Viet Tri 220kV substation have been replaced. Replacing all the ACSR500/64 mm2 conductors with 2 x AAC - 500 mm2 conductor and pole clamp accessories at the 220kV compartments of Son La 220kV and Viet Tri 220kV substations in accordance with the load capacity of the new conductor. Replacing low-voltage cables from the newly replaced current transformers to existing MK cabinets in the compartment.
Thanks to reasonable construction methods introduced by NPTPMB, the project has been successfully energized, meeting the requirements set forth.
The last positions were constructed by contractors on January 1, 2023
The completion of energizing and increasing the power flow of Viet Tri - Suoi Sap 2A 220kV transmission line in order to transmit power to the area currently operating in a state of high load when the system is operating normally and overloaded when the system encounters N-1 fault in peak load mode, rainy season.
The project helps to enhance the transmission capacity for the existing transmission line, contributing to evacuating energy of small hydropower plants in Son La province, meeting the load growth requirement for local economic and social development in Son La and Phu Tho provinces. Supporting transmission lines in the region to enhance the safe and stable operation of the national power system, especially contributing to ensuring electricity supply for the North in the hot summer months of 2023.