Schweitzer Engineering Laboratories SEL-300G - Page 37

Relay Element Settings iii
SEL-300G Instruction Manual Date Code 20020206
I.E.C. Long-Time Inverse Curve: C4 .........................................................................2-51
U.S. Short-Time Inverse Curve: U5 ...........................................................................2-51
Voltage-Controlled/Restrained Time-Overcurrent Elements .......................................................2-4
Element Description..............................................................................................................2-4
Functional Description ..................................................................................................2-4
Setting Descriptions ......................................................................................................2-5
Relay Word Bits ............................................................................................................2-6
Voltage-Controlled and Voltage-Restrained Time-Overcurrent Setting Calculation ...........2-6
Information Needed.......................................................................................................2-6
Recommendations .........................................................................................................2-6
Voltage-Controlled Time-Overcurrent Settings ....................................................2-6
Voltage-Restrained Time-Overcurrent Settings ....................................................2-7
Overcurrent Tripping.....................................................................................................2-8
Element Operating Characteristics........................................................................................2-8
Over/Under Voltage Elements ....................................................................................................2-10
Element Description............................................................................................................2-10
Functional Description ................................................................................................2-10
Setting Descriptions ....................................................................................................2-10
Relay Word Bits ..........................................................................................................2-11
Voltage Element Setting Calculation..................................................................................2-11
Loss-of-Potential (60LOP) Protection ........................................................................................2-14
Element Description............................................................................................................2-14
Functional Description ................................................................................................2-14
Setting Descriptions ....................................................................................................2-14
Relay Word Bits ..........................................................................................................2-14
100% Stator Ground Protection Elements ..................................................................................2-14
Element Description............................................................................................................2-14
Functional Description ................................................................................................2-14
Setting Descriptions ....................................................................................................2-16
Relay Word Bits ..........................................................................................................2-17
100% Stator Ground Protection Setting Calculation ..........................................................2-17
Information Needed.....................................................................................................2-17
Third-Harmonic Voltage Differential Setting Recommendations (four-wire
potentials required)..............................................................................................2-17
Third-Harmonic Neutral Undervoltage Setting Recommendations (use with
open-delta potentials) ..........................................................................................2-19
100% Stator Ground Fault Tripping............................................................................2-21
Element Operating Characteristics......................................................................................2-21
Out-of-Step Element–Single Blinder Scheme.............................................................................2-22
Element Description............................................................................................................2-22
Functional Description ................................................................................................2-22
Setting Descriptions ....................................................................................................2-25
Relay Word Bits ..........................................................................................................2-26
Settings Calculation ............................................................................................................2-26
Information Needed.....................................................................................................2-26
Recommendations .......................................................................................................2-26
Out-of-Step Element–Double Blinder Scheme...........................................................................2-28
Element Description............................................................................................................2-28
Functional Description ................................................................................................2-28
Settings Descriptions...................................................................................................2-31