INGEPAC EF LD is a complete segregated-phase line differential protection, designed for overhead transmission lines and underground cables of all voltage levels. Differential functions 87, 87LG, 87N V7f and 5th harmonic overexcitation Directional supervision CT error Saturation detector Load compensation Function 86 Distance functions 21 quadrilateral and MHO 21 high-speed Zone 1 extension Adaptation for double lines, series compensation and lines with capacitive transformers Backup for transformers Other functions 3x50/51 (67), 50N/51N (67N) 50G/51G 46TOC (67Q), 46IOC(67Q) 46FA open phase 50 CSC 2nd harmonic restraint 2nd and 5th harmonic blocking SOTF switch-on-to-fault 27, 59, 59N, 47 81M/m, 81 ROCOF 37 undercurrent 49 thermal image 32 power Tacon (heel setting) 85 teleprotection (21, 67/67Q) 68ZC, 68FF 78 power swing 25 synchronism 79 single-/three-pole 50 BF breaker failure (single-/three-pole) Fault locator Breaker supervision