Summary
This document presents a method developed by EPM to select transmission line protection schemes in a technical, standardized, and cost-efficient way. The approach combines classification criteria (SIR, line length, topology, and connection type) with a performance validation process based on large-scale short-circuit simulations under critical operating scenarios. Three protection schemes are evaluated: 87L, with high sensitivity but security risks; 85-21L/67N, a more economical and stable alternative; and 21L+67/67N, applicable to radial load-fed lines. For lines with SIR < 20 and length > 10 km operating in a ring configuration, compliance with performance criteria is verified through simulation to assign either the 8521L/67N scheme or, if requirements are not met, the 87L scheme. Generation characteristics are implicitly considered through the SIR calculation and simulation scenarios and therefore require no additional treatment.
Read more Read lessApplied to 126 lines at 110 kV and 220 kV, the method resulted in the assignment of 70 schemes using 87L, 50 using 85-21L/67N, and the retention of 6 using 21L+67/67N, thus avoiding the massive deployment of 87L. Among the alternatives evaluated, option 2A—selective assignment using existing multiplexed communication channels—achieved the best balance between security, technical performance, and CAPEX optimization.
Additional informations
| Publication type | Session Materials |
|---|---|
| Reference | B5_12275_2026 |
| Publication year | |
| Publisher | CIGRE |
| Country | Colombia |
| Study committees | |
| File size | 566 KB |
| Price for non member | 30 € |
| Price for member | 30 € |
Authors
CARROLL Juan - EPM; ALVAREZ Ramiro - EPM; VARGAS Juan - EPM
