Sepam - HV/MV Protection and control units (ENG) - Trinet

Directional phase overcurrentANSI code 67Operating principlefunction n° F52X* 1 ≤ X ≤ 2OperationI1V1U13V1V1U21PrincipleThis protection is three-phase. It includes a phaseovercurrent function combined with directiondetection. It picks up when the phase overcurrentfunction in the chosen direction (normal or inverse)is activated for at least one of the 3 phases.It is time-delayed. The time delay may be definite(definite DT) or IDMT (standard inverse SIT,very inverse VIT or LTI (1) , extremely inverse EIT,ultra inverse time UIT). See phase overcurrentprotection curves in appendix.(1)The very inverse time VIT delay setting range may be usedto create LTI curves.Vnormalzone90°I1ϕ1V2U32U13θ = 30°V390°inversezoneV2I2V3I3U21θ = 30°ϕ390°V2Logic data K859 = 1 (K860) may be used to inhibitstart up of the time delay (normal zone) andK860 = 1 may be used to inhibit start up ofthe time delay (inverse zone)(regarding use, refer to “start-up of time delays”in appendix).inversezoneU32U13θ = 30°I2normalzoneϕ2I3normalzoneinversezoneThe direction of the current is determinedby the phase current measurement in relationto a polarization value.The polarization value is the system voltagein quadrature with the current for cos ϕ = 1(90° connection angle).The current vector plane of a phase is divided into2 half-planes which correspond to the normal zoneand the inverse zone. The characteristic angle θ isthe angle of the line perpendicular to the boundaryline between the 2 zones and the polarization value.The protection is operational whenever thepolarization voltage value is greater than 1.5% of Un.normalzonenormalzoneI1inversezoneI1ϕ1ϕ1θ = 45°U32θ = 60°inversezoneU13θ = 45°inversezoneϕ2I2normalzoneθ = 45°ϕ3I3normalzoneθ = 60°U21U21inversezoneinversezoneinversezoneU32U13ϕ2θ = 60°normalzoneI2ϕ3I3normalzone* for versions earlier than version 9802 SFT2800,the function number is F51X and the protection is 2-phase(phases L1 and L3).2/6 Protection functions