Debaters attending the Daejeon Tram supply and route operation method service results held in Daejeon City Hall on the 4th of the Daejeon City Hall are engaged in heated discussions by exchanging various opinions. Reporter Shin ShinUnlike the original plan, the Daejeon Metro Line 2 tram, which was planned as a wireless operation method without electric cords for all sections, is expected to be promoted as a’provisional hybrid method’ in which batteries and electric cords are installed for some sections. As a result of the service that both methods, such as battery and supercapacitor, could not handle the long circulation line of 36.6 km, the possibility of installation of electric wires, which is a temporary line, increased in some sections, which account for about a third of the entire section.
On the 4th, Daejeon City held an expert discussion on the results of the Daejeon tram supply and route operation method service in the city hall conference room. In a service report, Min Jae-hong, a senior researcher at the Korea Railroad Research Institute, said, “As a result of a detailed review of the vehicle power supply method, it is difficult to apply the wireless loop line.”
Considering the conditions of the Daejeon area, the power supply method suitable for the tram is compressed into two methods, such as’battery’ and’supercapacitor’ among several methods. The’battery’ method uses a high-density battery to drive, and the’supercapacitor’ method uses a supercapacitor that rapidly charges and discharges a large amount of power, charging at a stop and driving to the next station. In both methods, considering the battery and energy storage capacity, it was concluded that the long distance of 36.6km cannot be operated without wires at once. This is because, as a result of each energy consumption analysis, which indicates the battery surplus when the tram is operated, the lowest SOC (residual capacity) value is lower than 25% required for stable operation, and the battery margin is analyzed to be insufficient.
In addition, when the circular line was divided into two sections, Jinjam-Government Building (21.7㎞) and Jinjam-Seodaejeon (18.6㎞), the result of reviewing whether non-wireless lines were possible. It was concluded that it was difficult to operate a wireless wire with a power supply method that could be reviewed.
Eventually, the city of Daejeon, which initially announced the promotion of the construction of a tram without a temporary line, was in a situation where the plan had to be revised drastically as the result of the service requiring that a temporary line should be installed even in some sections. “Overall, it is judged that the method of applying battery + wiring while maintaining the circular line is most suitable for Daejeon Urban Railroad Line 2,” said a senior researcher. “In relation to the dispatch and route operation method, opinions were provided through domestic as well as overseas vehicle manufacturers. He added, “We will introduce the related contents in December of this year after being verified by the Daejeon City Railway Technical Advisory Committee.”
The city side plans to select the installation section of the temporary line and announce it in the detailed design stage, taking into account the structurally necessary parts and aspects that do not damage the landscape.
Meanwhile, Daejeon Urban Railway Line 2, which is being promoted with the goal of opening and completion in 2027, will be built in the form of a tram (tram). The main line (33.4㎞) and the branch line (3.2㎞), which are circular lines, are 36.6㎞, and 35 stations, 1 vehicle base, and 4 main bases will be installed. The total project cost is estimated at 749.2 billion won and the average daily users is about 137,000. Reporter Jung Min-ji