LARGEST ROTATING CONVERTERS FOR INTERCONNECTING THE RAILWAY POWER SUPPLY WITH THE PUBLIC ELECTRICITY SYSTEM, IN KERZERS AND SEEBACH, SWITZERLAND

Rotating frequency converter sets for interconnecting the railway power supply and the national electricity system, while allowing some flexibility in the frequency relationship, are today indispensable connecting elements in countries where the railways are supplied at a frequency of 16 2/3 Hz. In order to meet the rising demands of the railway power supply, resulting primarily from the introduction of high-power traction units, the link with the powerful national 50 Hz system has had to be strengthened. In 1974/75 two interconnecting converters rated 33 multiplied by (times) 75 Mw each came into service in the Kerzers converter station of the Swiss Federal Railways. Two more sets rated 60 Mw each are now being constructed for the SBB's converter station in Seebach (Zurich). The development of flexible system interconnecting converters are described, with reference to these latest sets, which are the world's largest.