The SPDB consists of modular built semiconductor switches (SSPC – Solid State Power Controller), which can be used to control different types of loads in the cabin. They have integrated smart metering and monitoring functions. Further on, the SSPC can be configured and. secondary unit substation is a close-coupled assembly consisting of enclosed primary high voltage equipment, three-phase power transformers, and enclosed secondary low-voltage equipment. The following electrical ratings are typical: As a result of locating power transformers and their close-coupled. Primary distribution systems consist of feeders that deliver power from distribution substations to distribution transformers. A feeder usually begins with a feeder breaker at the distribution substation. Additionally. The purpose of this manual is to assist the user in developing safe and eficient procedures for the installation, maintenance and operation of the equipment. For additional information, refer to NEMA Standards Publication PB2. 1 “General Instructions for Proper Handling, Installation, Operation, and. SafePlus can be configured with a maximum of 5 modules in one SF tank with an internal busbar. Unit substation assemblies shall be configured as.