Global

Top page > Learn(History/Science) > Toshiba Firsts of Their Kind > World's Largest Hydropower Generating Units Installed on the Yalu River

World's Largest Hydropower Generating Units Installed on the Yalu River

Contract awarded for water turbines and generators for the Supung Power Station in 1938 amid rising political tensions at home and abroad

World's Largest Hydropower Generating Units Installed on the Yalu River

In the early Showa Period (1930s), a project was proposed to develop hydropower sources on the Pujon, Heochun, and Changjin rivers in the northern part of the Korean Peninsula to exploit the abundant hydropower potential in that area. The aim of the project was to supply electric power for the mass-production of chemical fertilizers, and the Korea Nitrogenous Fertilizer Company was established for this purpose. The hydropower development was managed by Korea Hydroelectric Power Company (KHPC) and Changjin Hydroelectric Power Company (CHPC).

At the beginning, Shibaura Engineering Works and Dengyosha Prime Mover Works (both of which were Toshiba's predecessors) received an order from KHPC for two vertical-shaft Francis turbine units for the Pujon River No. 2 Power Station. Thereafter, they received orders for a total of 35 units of turbines and generators for 11 power stations (all except for one power station in the whole project) from both hydroelectric power companies.

Most of these machines were unprecedented in those days in terms of operating head and unit capacity, so many U.S. and European manufacturers were competing with Shibaura and Dengyosha. However, they overcame the tough competition and successfully won the contracts, reflecting the customers' reliance on the companies and their technologies.

After the successful completion of the project, another major project was proposed to develop a large hydropower station called the Supung Power Station on the Yalu River on the border between Manchuria and Korea. Owing to their good performance in the previous project, Shibaura and Dengyosha successfully won the contract for all seven turbines rated at 105 MW each and five generators rated at 100 MVA each in March 1938 from Yalu River Hydropower Company, the developer of the project. At that time they were the world's largest units in terms of unit capacity.

The 105 MW turbines were vertical-shaft Francis turbines operating with an 82-meter head. Three of them were designed to be operated at both 50 and 60 Hz, while two were designed for 50 Hz and the other two for 60 Hz. They surpassed by far the 85 MW turbines at the Boulder Dam in the U.S., which were the largest turbines before that time. Political tension was already on the rise around Japan at the time of the contract. Therefore, upon receipt of the order, Shibaura and Dengyosha took immediate action for the production of these large-scale machines such as design work, procurement of materials, and so forth. In particular, they requested various material manufacturers for their cooperation to ensure smooth supplies of the large amounts of materials required to build these machines.

In September 1938, the embedded parts of the first turbine were shipped to the site and the main part of the turbine was completed in the shop early in the autumn of 1939. According to the documents detailing the shipments, these recordbreaking super-size turbines were shipped thereafter at an average interval of 4.5 months. This was an amazingly short interval for wartime, when labor and materials were scarce. Shibaura and Dengyosha built a new factory with a large pit for shop assembly of the huge generators and to perform rotation tests before shipment. The rotation test of the first 50/60 Hz generator was conducted in June 1940, verifying its performance and operational reliability.

The first unit was commissioned in September 1941 and a commemoration ceremony was held at the site. We can feel the sense of pride in those who accomplished this great task through a framed inscription written by former senior managing director Jugoro Otaguro, who was the founder of the turbine manufacturing business in Dengyosha. The inscription says, “In the early days, half a horsepower. Today, 143,000 horsepower, the highest in the world.”

The completion of these largest generators in the world owes much to the dedicated efforts of the engineers involved. They succeeded in achieving many technological breakthroughs toward larger unit capacity, higher voltage, larger machine design, and improvement of the bearings and the generator's construction as a whole.

Written by Jugoro Otaguro “In the early days, half a horsepower. Today, 143,000 horsepower, the highest in the world.”

Written by Jugoro Otaguro “In the early days, half a horsepower. Today, 143,000 horsepower, the highest in the world.”

105 MW turbine under construction at Yalu River Power Plant

105 MW turbine under construction at Yalu River Power Plant

Related Links

Learn (History/Science) Top Page

Toshiba Science Museum
2F Lazona Kawasaki Toshiba Bldg., 72-34, Horikawa-Cho, Saiwai-Ku, Kawasaki 212-8585, Japan
TEL. 044-549-2200

To Top