The world’s first 500kV underground substation.

Nước Nhật được biết đến là những công trình ngầm mà cả thế giới ngưỡng mộ. Trạm biến áp 500kV lắp đặt

Japan is renowned for its underground structures that are admired worldwide, and a 500kV substation installed underground is even more impressive.

The power transmission system managed by the Tokyo Electric Power Company (TEPCO) comprises 21,208 km of transmission lines and 1,582 substations with a total capacity of 269,570 MVA. TEPCO has an underground substation ratio of 13% overall, 39% in the capital, Tokyo, and as high as 86% in Tokyo’s three central wards, which includes even the 500kV substations installed underground.

The National Power Transmission Corporation (EVNNPT) visited TEPCO to study their experience in managing a power transmission system and to learn about the world’s first 500kV underground substation.

TEPCO’s underground 500kV substation is an extremely effective solution, placing 500kV and 275kV substations deep within the heart of major cities—especially the capital, Tokyo—to meet the ever-growing load demands, improve the reliability of power supply, and reduce energy losses. This solution is particularly suitable for large cities where land acquisition and site clearance for building substations are increasingly challenging. The investment cost for an underground substation is about three times that of a traditional outdoor substation, but the building constructed above the underground substation can be utilized for commercial purposes.

The building above the Shin-Toyosu underground 500kV substation is visible from the outside; the equipment is installed across four basement levels, with the first level serving as the substation’s office.

The substation includes: 500/275 kV transformers rated at 3×1,500 MVA; 275/66 kV transformers rated at 6×300 MVA. The substation comprises one above-ground level and four underground levels. The first level is used as the substation’s office, and equipment is installed on the four basement levels. From the second floor of the building above the substation, TEPCO rents office space and headquarters to other companies.

The EVNNPT delegation visited to study the 500kV underground substation, which is the world’s first of its kind, and it has been in operation since November 2000. Located in the heart of Tokyo, this substation plays a critical role in ensuring power supply for the area. It was converted from a manned station to an unmanned one in 2016 and is remotely controlled by the Shin-Keiyo Control Center, 40 km away from the substation.

(500/275 kV GIT Transformer)

The EVNNPT delegation took commemorative photos with TEPCO officials.