AI-generated summary
· Rir · 07/22/2026
Nova Scotia Power filed responses to four NSEB information requests on the $2.4M unforeseen replacement of the 67C-T64 substation transformer at Whycocomagh, citing insulation failure after 40 years of service
AI summary
- The failed transformer was installed in 1986 and was 40 years old at the time of replacement, below the ~50-year expected service life used in Nova Scotia Power Asset Management plans (IR-1)
- The phase-to-phase fault was caused by cumulative insulation degradation over 40 years; high-side fuse protection operated as intended to isolate the fault and prevent propagation, though external protections cannot prevent internal dielectric breakdown (IR-2)
- The transformer carried no supplier warranty at the time of failure, as it was installed in 1986 and typical warranty periods last only 2–5 years (IR-2(c))
- IR-3 responses are partially redacted; non-confidential portions confirm the replacement transformer ordered for the Bridgewater substation costs less than the 67C-Whycocomagh unit, with price reductions attributed to improved freight market conditions and minimal reorder design costs
- NSPI's IR-4 response on protective measures for the new transformer cross-references IR-2(b), reiterating that external protection systems cannot prevent internal insulation faults
Disclaimer: This summary was generated by AI from the filings it describes. We take care to make it accurate, but errors are possible - and it isn't advice. Only the filings themselves are the record: if you're relying on something here, confirm it against the source documents or the Nova Scotia Energy Board's own record. Full disclaimer →
What was filed
Documents filed on this day
- N-2 NSPI (NSEB) RIR 1 to 4 - Redacted
- N-2(C) NSPI (NSEB) RIR 1 to 4 - Confidential
- 102881 Letter NSPI re: RIRs Justification for partially confidential material