Schweitzer Engineering Laboratories SEL-351-5 - Table of Contents

Date Code 20020426 Overcurrent, Voltage, Synchronism Check, Frequency, and Power Elements i
SEL-351-5, -6, -7 Instruction Manual
TABLE OF CONTENTS
SECTION 3: OVERCURRENT, VOLTAGE, SYNCHRONISM
CHECK, FREQUENCY, AND POWER ELEMENTS........3-1
Instantaneous/Definite-Time Overcurrent Elements.................................................................... 3-1
Phase Instantaneous/Definite-Time Overcurrent Elements.................................................. 3-1
Settings Ranges............................................................................................................. 3-1
Accuracy....................................................................................................................... 3-1
Pickup Operation.......................................................................................................... 3-3
Directional Control Option........................................................................................................... 3-5
Torque Control ............................................................................................................. 3-5
Combined Single-Phase Instantaneous Overcurrent Elements..................................... 3-6
Pickup and Reset Time Curves..................................................................................... 3-6
Phase-to-Phase Instantaneous Overcurrent Elements........................................................... 3-8
Setting Range................................................................................................................ 3-8
Accuracy....................................................................................................................... 3-8
Pickup Operation.......................................................................................................... 3-8
Pickup and Reset Time Curves..................................................................................... 3-8
Neutral Ground Instantaneous/Definite-Time Overcurrent Elements.................................. 3-8
Settings Ranges........................................................................................................... 3-11
Accuracy..................................................................................................................... 3-11
Pickup and Reset Time Curves................................................................................... 3-11
Residual Ground Instantaneous/Definite-Time Overcurrent Elements.............................. 3-12
Settings Ranges........................................................................................................... 3-13
Accuracy..................................................................................................................... 3-13
Pickup and Reset Time Curves................................................................................... 3-14
Negative-Sequence Instantaneous/Definite-Time Overcurrent Elements.......................... 3-14
Settings Ranges........................................................................................................... 3-14
Accuracy..................................................................................................................... 3-14
Pickup and Reset Time Curves................................................................................... 3-15
Time-Overcurrent Elements.......................................................................................................3-16
Phase Time-Overcurrent Elements..................................................................................... 3-16
Settings Ranges (51PT Element Example)................................................................. 3-17
Accuracy..................................................................................................................... 3-18
Logic Outputs (51PT Element Example) ................................................................... 3-18
Torque Control Switch Operation (51PT Element Example)..................................... 3-18
Torque Control Switch Closed ........................................................................... 3-18
Torque Control Switch Open.............................................................................. 3-19
Control of Logic Point TCP................................................................................ 3-19
Directional Control Option................................................................................. 3-19
Torque Control.................................................................................................... 3-20
Reset Timing Details (51PT Element Example) ........................................................ 3-20
Setting 51PRS = Y.............................................................................................. 3-21
Setting 51PRS = N.............................................................................................. 3-21
Operation of Single-Phase Time-Overcurrent Elements (51AT, 51BT, 51CT) ......... 3-21
Neutral Ground Time-Overcurrent Element....................................................................... 3-23
Settings Ranges........................................................................................................... 3-24
Accuracy..................................................................................................................... 3-24
Residual Ground Time-Overcurrent Element..................................................................... 3-24
Settings Ranges........................................................................................................... 3-25