Sel 751A - Page 14

xii
SEL-751A Relay Instruction Manual Date Code 20100129
List of Figures
Figure 3.4 Tools Menu............................................................................................................................. 3.4
Figure 3.5 Device Response to the ID Command ................................................................................... 3.4
Figure 3.6 Selection of Drivers................................................................................................................ 3.7
Figure 3.7 Update Part Number............................................................................................................... 3.8
Figure 3.8 New Setting Screen ................................................................................................................ 3.8
Figure 3.9 Expressions Created With Expression Builder .................................................................... 3.10
Figure 3.10 Composite Screens for Retrieving Events............................................................................ 3.11
Figure 3.11 Saving the Retrieved Event .................................................................................................. 3.12
Figure 3.12 Device Overview Screen ...................................................................................................... 3.13
Figure 3.13 Control Screen...................................................................................................................... 3.14
Figure 3.14 Remote Operation Selection................................................................................................. 3.14
Figure 4.1 Instantaneous Overcurrent Element Logic ............................................................................. 4.7
Figure 4.2 Ground Fault Protection Using Core-Balance CT ................................................................. 4.8
Figure 4.3 Phase Time-Overcurrent Elements 51AT, 51BT, and 51CT ................................................ 4.11
Figure 4.4 Maximum Phase Time-Overcurrent Elements 51P1T and 51P2T....................................... 4.12
Figure 4.5 Negative-Sequence Time-Overcurrent Element 51QT ........................................................ 4.13
Figure 4.6 Neutral Time-Overcurrent Elements 51N1T and 51N2T..................................................... 4.14
Figure 4.7 Residual Time-Overcurrent Elements 51G1T and 51G2T................................................... 4.15
Figure 4.8 U.S. Moderately Inverse Curve: U1 ..................................................................................... 4.17
Figure 4.9 U.S. Inverse Curve: U2 ........................................................................................................ 4.18
Figure 4.10 U.S. Very Inverse Curve: U3................................................................................................ 4.19
Figure 4.11 U.S. Extremely Inverse Curve: U4....................................................................................... 4.20
Figure 4.12 U.S. Short-Time Inverse Curve: U5 .....................................................................................4.21
Figure 4.13 IEC Class A Curve (Standard Inverse): C1.......................................................................... 4.22
Figure 4.14 IEC Class B Curve (Very Inverse): C2................................................................................. 4.23
Figure 4.15 IEC Class C Curve (Extremely Inverse): C3........................................................................ 4.24
Figure 4.16 IEC Long-Time Inverse Curve: C4 ...................................................................................... 4.25
Figure 4.17 IEC Short-Time Inverse Curve: C5 ......................................................................................4.26
Figure 4.18 Undervoltage Element Logic................................................................................................ 4.31
Figure 4.19 Overvoltage Element Logic.................................................................................................. 4.32
Figure 4.20 Synchronism-Check Voltage Window and Slip Frequency Elements.................................. 4.33
Figure 4.21 Synchronism-Check Elements ............................................................................................. 4.34
Figure 4.22 Angle Difference Between VP and VS Compensated by Breaker Close Time
(fP < fS and VP Shown as Reference in This Example) .................................................. 4.39
Figure 4.23 Three-Phase Power Elements Logic..................................................................................... 4.43
Figure 4.24 Power Elements Operation in the Real/Reactive Power Plane............................................. 4.44
Figure 4.25 Power Factor Elements Logic .............................................................................................. 4.45
Figure 4.26 Loss-of-Potential (LOP) Logic............................................................................................. 4.47
Figure 4.27 Over- and Underfrequency Element Logic .......................................................................... 4.48
Figure 4.28 81R Frequency Rate-of-Change Scheme Logic................................................................... 4.49
Figure 4.29 Trip Logic............................................................................................................................. 4.51
Figure 4.30 Close Logic .......................................................................................................................... 4.53
Figure 4.31 Reclose Supervision Logic (Following Open Interval Time-Out) ....................................... 4.54
Figure 4.32 Reclose Supervision Limit Timer Operation........................................................................ 4.55
Figure 4.33 SEL-751A Relays Installed at Both Ends of a Transmission Line in a
High-Speed Reclose Scheme............................................................................................ 4.57
Figure 4.34 Reclosing Relay States and General Operation.................................................................... 4.60
Figure 4.35 Reclosing Sequence From Reset to Lockout With Example Settings.................................. 4.64
Figure 4.36 Reclose Blocking for Islanded Generator ............................................................................ 4.71
Figure 4.37 Sequence Coordination Between the SEL-751A and a Line Recloser ................................ 4.73
Figure 4.38 Operation of SEL-751A Shot Counter for Sequence Coordination With Line Recloser
(Additional Settings Example 1) ...................................................................................... 4.74
Figure 4.39 Operation of SEL-751A Shot Counter for Sequence Coordination With Line Recloser
(Additional Settings Example 2) ...................................................................................... 4.75
Figure 4.40 Demand Current Logic Outputs ........................................................................................... 4.77
Figure 4.41 Response of Thermal and Rolling Demand Meters to a Step Input (Setting
DMTC = 15 minutes) ....................................................................................................... 4.78
Figure 4.42 Voltage V
S
Applied to Series RC Circuit............................................................................. 4.79