115kV/230kV/345kV/765kV Line Clearance & Remediation – NERC – FAC Line Rating Alert

115kV/230kV/345kV/765kV Line Clearance & Remediation – NERC – FAC Line Rating Alert

1,400 Miles of Rating Studies – (46) Transmission Lines

The purpose of this project was to evaluate the Client’s critical transmission lines and identify significant discrepancies between the record documentation and the current field condition in response to the NERC Recommendation.

Project Scope:
Using commercially obtained LiDAR surveys, model the Client’s transmission lines in PLS-CADD.  Perform evaluation and comprehensive NESC clearance reporting, consisting of IEEE738 back calculation of line tensions, calculation and verification of existing line ratings and clearance reports at Normal (NOR), Long-Term Emergency (LTE), and Short-Term Emergency (STE) load ratings and operating conditions at the Client’s standard maximum conductor temperature and the maximum circuit rating conductor temperature.

Because of Realtime’s expertise with over 10,000 miles of LiDAR surveys and ratings studies, Realtime was able to suggest a clearance remediation option using the Client’s known switching surge factor information to calculate reduced NESC clearance requirements.  This was a “zero dollar” remediation option that saved the customer $5.2 million dollars in remediation costs.

The final reports yielded remediation estimates for the conditions and parameters identified, total number of spans with encroachments, reporting encroachments by wire phase to reduce remediation efforts, and identification of the current maximum operating temperature and load rating without clearance encroachments for standard summer and winter NOR, LTE, and STE conditions.

Clearance encroachments were categorized by severity, and remediation options were developed for each category.  Engineering estimates were provided in cost groupings based on the severity encroachment and extrapolated out to all potential encroachments for each phase and each facility.  Additional costs with regard to construction mobilization, access, environmental impact, permitting, etc., were also estimated utilizing Client GIS data provided.

Realtime is continued this effort with the Client through detailed field validation of encroachments and lowest cost remediation design engineering and construction.