Schweitzer Engineering SEL-351P - Voltage)

ii Overcurrent, Voltage, Synchronism Check, and Frequency Elements Date Code 990430
SEL-351P Manual Técnico
Residual Ground Time-Overcurrent Elements ...................................................................3-24
Settings Ranges ...........................................................................................................
3-26
Accuracy .....................................................................................................................
3-26
Negative-Sequence Time-Overcurrent Element .................................................................
3-27
Settings Ranges ...........................................................................................................
3-28
Accuracy .....................................................................................................................
3-28
Voltage Elements........................................................................................................................
3-29
Voltage Values....................................................................................................................
3-29
Voltage Element Settings....................................................................................................
3-29
Accuracy .....................................................................................................................
3-34
Voltage Element Operation.................................................................................................
3-34
Undervoltage Element Operation Example ................................................................
3-34
Overvoltage Element Operation Example...................................................................
3-35
Voltage Elements Used in POTT Logic .............................................................................
3-35
Synchronism Check Elements ....................................................................................................
3-35
Synchronism Check Elements Settings...............................................................................
3-36
Accuracy .....................................................................................................................
3-36
Synchronism Check Elements Voltage Inputs....................................................................
3-38
System Frequencies Determined from Voltages V
A
and V
S
.......................................3-39
Synchronism Check Elements Operation ...........................................................................
3-39
Voltage Window .........................................................................................................
3-39
Other Uses for Voltage Window Elements.........................................................
3-39
Block Synchronism Check Conditions .......................................................................
3-40
Slip Frequency Calculator...........................................................................................
3-40
Angle Difference Calculator .......................................................................................
3-41
Voltages V
P
and V
S
are “Static”..........................................................................3-41
Voltages V
P
and V
S
are “Slipping” .....................................................................3-41
Angle Difference Example (voltages V
p
and V
s
are “slipping”).........................3-43
Synchronism Check Element Outputs.........................................................................
3-44
Voltages V
P
and V
S
are “Static”..........................................................................3-44
Voltages V
P
and V
S
are “Slipping” .....................................................................3-44
Synchronism Check Applications for Automatic Reclosing and Manual Closing.............
3-45
Frequency Elements....................................................................................................................
3-46
Frequency Element Settings ...............................................................................................
3-46
Accuracy .....................................................................................................................
3-48
Create Over- and Underfrequency Elements ..............................................................
3-48
Overfrequency Element.......................................................................................
3-49
Underfrequency Element.....................................................................................
3-49
Frequency Element Operation ............................................................................................
3-49
Overfrequency Element Operation .............................................................................
3-49
Underfrequency Element Operation ...........................................................................
3-50
Frequency Element Voltage Control...........................................................................
3-50
Other Uses for Undervoltage Element 27B81.....................................................
3-50
Frequency Element Uses.....................................................................................................
3-50