Topic:"Distribution" in M03232

During the past three years a minimal number of relays tested required replacement or repair due to functional failure (34, 2%). Should any of these relays have failed, backup relays would have responded to prevent customer outages. The to...

AI summary NSPI reports that only 2% of tested relays required replacement or repair over the past three years, suggesting a ten-year testing cycle may be more appropriate. They request UARB approval for this change, excluding Bulk Power System Elements which must be tested every four years.

NON-CONFIDENTIAL 1 Request IR-1: 2 3 Nova Scotia Power's 2006-2007 Relay Testing Report (letter dated July 2, 2008), indicated 4 1712 relays were included in the transmission test program. The 2008 Relay Testing 5 Report (letter dated Apri...

AI summary This document outlines Nova Scotia Power's relay testing program from 2006 to 2009, including the number of relays tested and changes in the program over time. It also responds to questions regarding customer-owned relays and the total number of relays in the system.

NON-CONFIDENTIAL 1 Response IR-1: (cont'd) 2 3 The database of relays contains all mechanical relays in the system. A number of those 4 relays are no longer in service because they have been replaced with newer digital relays, 5 or parts o...

AI summary The response discusses the database of relays in NSPI's system, noting that many mechanical relays have been replaced by digital ones or removed due to system retirements and upgrades for renewable energy integration. Testing of relays is conducted according to a 3-year program and NPCC requirements, with one relay not tested due to the significant impact of its removal.