Overview
Nowadays generators usually come with smart controllers such as Deep Sea Controller (DSC) to enable multiple generators to automatically run in sync with each other. However, for this job our client requires a manual generator synchronizing system for an island in Maldives.
Manual Generator Synchronizing Operation
For manual synchronizing, a Synchronous Scope is used to read the frequency of the back up generator output and check if the frequency is in-phase with the bus. When the frequency of the back up generator is 5-10 degrees apart from the bus, the operator must immediately close the contactor of the back up generator. As a secondary protection, the Synchronous Scope has a CheckSync function where if the generator frequency and bus frequency are out of phase, the CheckSync function will not be enabled, thus the operator will not be able to close the contactor.
Phase Monitoring
For another level of protection, a 3 phase monitoring control relay is used to monitor the bus voltage, whether is it in phase, overvoltage or out of sequence. However, point to note was that monitoring reverse voltage is also important, in an event where the generator becomes the load, drawing current instead. Hence in future we would consider to add in the reverse voltage monitoring function for such a system.