Schweitzer Engineering Laboratories SEL-352-1 - Page 71

Date Code 20010731 Breaker Logic iii
SEL-352-1, -2 Instruction Manual
Operating Characteristic..................................................................................................... 3-38
Setting Description .............................................................................................................3-39
Breaker Close Signals (CLOSE, MCLOSE) .............................................................. 3-39
Phase Current Unbalance Ratio (46UB)..................................................................... 3-40
Phase Current Unbalance Enable (UBLOG) .............................................................. 3-40
Close Input (UCpu)..................................................................................................... 3-40
Unbalance Pending Failure (UPpu) ............................................................................ 3-40
Unbalance Breaker Failure (UFpu) ............................................................................ 3-41
Setting Calculations............................................................................................................3-41
Phase Current Unbalance Ratio (46UB)..................................................................... 3-41
Application Guideline ........................................................................................................ 3-41
Loss-of-Dielectric Detection ...................................................................................................... 3-43
Application Description...................................................................................................... 3-43
Operating Characteristic..................................................................................................... 3-43
Setting Description .............................................................................................................3-44
Dielectric Pressure Level Indicators (LOD1, LOD2, LODCT) ................................. 3-44
Loss-of-Dielectric Logic Enable (DELOG) ............................................................... 3-44
Leak Timer (L2pu) ..................................................................................................... 3-45
Breaker Alarm Logic.................................................................................................................. 3-45
Application Description...................................................................................................... 3-45
Operating Characteristic..................................................................................................... 3-45
Failed CB Trip Resistors Put in Service..................................................................... 3-46
Failed CB Close Resistors Put in Service................................................................... 3-47
52A Contradicts Voltage ............................................................................................ 3-47
Current While Open.................................................................................................... 3-48
Trip While Open ......................................................................................................... 3-48
Breaker Did Not Close................................................................................................ 3-48
Current After MOD Trip ............................................................................................ 3-49
MOD Contradicts Current .......................................................................................... 3-49
Slow Trip .................................................................................................................... 3-49
Slow Close .................................................................................................................. 3-50
Potential Transformers Disagree ................................................................................ 3-50
TABLES
Table 3.1: Example Line/Breaker Information .....................................................................................3-4
Table 3.2: Breaker Failure Scheme Selection ....................................................................................... 3-5
Table 3.3: Open Conductor Detection Specifications......................................................................... 3-43