Date Code 20010719
701 Motor Protection Relay
SEL
OGIC
®
Control Equations & Relay Logic
Selected Relay Logic Diagrams
B.39
Figure B.16 Over-/Underfrequency Element Logic.
n =
freq =
81DnP =
FNOM =
SINGLEV =
DELTA_Y =
Va =
Vb =
Vb =
Vab =
Vbc =
Vca =
81DnD =
81DnT =
Frequency Elements 1-3
Measured Frequency
Frequency Pickup Setting
Nominal Frequency Setting
Single PT Enabled
Delta PT Enabled
Measured Phase Voltage
Measured Phase Voltage
Measured Phase Voltage
Measured Phase-to-Phase Voltage
Measured Phase-to-Phase Voltage
Measured Phase-to-Phase Voltage
Over-/Under Frequency Element Pickup Time Delay
Definite-Time Delayed Over-/Underfrequency Element
Relay Word Bit
DELTA_Y=D
|Vab|
|Vbc|
|Vca|
20V
SINGLEV=Y