3.24 Definite-Time Overcurrent Protection (Function Group DTOC1 and DTOC2) ...........3-149
3.24.1 Enabling or Disabling DTOC Protection ......................................................................................................3-149
3.24.2 Selecting the Measured Variables ............................................................................................................. 3-149
3.24.3 Inrush Restraint .........................................................................................................................................3-150
3.24.4 Definite-time Overcurrent Protection 1 (Including Short-circuit Direction Determination) ........................ 3-151
3.24.5 Load Flow Direction ...................................................................................................................................3-154
3.24.6 Definite-time Overcurrent Protection 2 ..................................................................................................... 3-156
3.25 Definite-Time Overcurrent Protection, Residual Current System (Function Group
DTOCN) ...................................................................................................................3-158
3.25.1 Enabling or Disabling DTOCN Protection ................................................................................................... 3-158
3.25.2 Starting and Tripping .................................................................................................................................3-158
3.26 Inverse-Time Overcurrent Protection (Function Group IDMT) ................................. 3-160
3.26.1 Disabling and Enabling IDMT Protection ....................................................................................................3-160
3.26.2 Time-Dependent Characteristics ............................................................................................................... 3-161
3.26.3 Selecting the Measured Variables ............................................................................................................. 3-164
3.26.4 Inrush Restraint .........................................................................................................................................3-165
3.26.5 Determining Trip Time ...............................................................................................................................3-166
3.26.6 Direction Measurement .............................................................................................................................3-167
3.26.7 Load Flow Direction ...................................................................................................................................3-169
3.26.8 Holding Time ............................................................................................................................................. 3-172
3.27 Distance Protection Z<t (Function Group DIST) ......................................................3-173
3.27.1 Enable/Disable the Distance Protection .....................................................................................................3-173
3.27.2 Distance Protection Blocking .....................................................................................................................3-173
3.27.3 Base Point Release for Impedance and Direction Determination .............................................................. 3-174
3.27.4 Inrush Stabilization ....................................................................................................................................3-175
3.27.5 Distance and Directional Measurement .....................................................................................................3-176
3.27.6 Impedance-Time Characteristics ...............................................................................................................3-179
3.28 Measuring-Circuit Monitoring (Function Group MCMON) .........................................3-181
3.28.1 Voltage Monitoring .................................................................................................................................... 3-182
3.28.2 Multiple signaling of the monitoring functions ...........................................................................................3-182
3.29 Thermal Overload Protection (Function Group THERM) .......................................... 3-184
3.29.1 Readiness of Thermal Overload Protection ................................................................................................3-184
3.29.2 Operating Modes .......................................................................................................................................3-184
3.29.3 Coolant Temperature Effect ...................................................................................................................... 3-185
3.29.4 Minimum Coolant Temperature .................................................................................................................3-185
3.29.5 Thermal Overload Protection Operation without Coolant Temperature (Ambient) Acquisition ..................3-186
3.29.6 Relative Replica .........................................................................................................................................3-186
3.29.7 Absolute Replica ........................................................................................................................................3-187
3.29.8 Tripping Characteristics .............................................................................................................................3-187
3.29.9 Warning Signal .......................................................................................................................................... 3-188
3.29.10 Trip ............................................................................................................................................................3-189
3.29.11 Cooling ...................................................................................................................................................... 3-190
3.29.12 Resetting ...................................................................................................................................................3-190
3.30 Under and Overvoltage Protection (Function Group V<>) ......................................3-191
3.30.1 Disabling and Enabling V<> Protection .....................................................................................................3-191
3.30.2 Voltage Monitoring .................................................................................................................................... 3-191
3.30.3 Time Characteristic ................................................................................................................................... 3-193
3.30.4 Voltage Window Function ..........................................................................................................................3-193
3.31 Over-/Underfrequency Protection (Function Group f<>) ........................................ 3-194
3.31.1 Disabling or Enabling Over‑/Underfrequency Protection ............................................................................3-194
3.31.2 Operating Modes of Over-/Underfrequency Protection ..............................................................................3-194
3.31.3 Frequency Monitoring ................................................................................................................................3-195
3.31.4 Frequency Monitoring Combined with Differential Frequency Gradient Monitoring (df/dt) ........................3-195
3.31.5 Frequency Monitoring Combined with Mean Frequency Gradient Monitoring (Δf/Δt) ................................ 3-195
P638 Table of Contents
4 P638/EN M/R-g8-D // P638‑305‑671