Design for the uninterruptible power supply system at the NHK broadcasting center

The uninterruptible power supply (UPS) system at the NHK broadcasting center, Japan, has been restructured. The restructured system has been designed with emphasis on the following aspects: (1) parallel operation of several UPS units; (2) the system control configuration; and (3) the distribution system feeding power to the broadcasting equipment. A brief overview of this system is presented. The redundancy system was structured to provide for exchange switching with a bypass power source so as to allow the continued supply of power under any circumstances. Hence, the system was designed to permit backup in the event of malfunctions as well as separate system power supply during the execution of maintenance work, thus enhancing both reliability and maintenance characteristics