Ashida ADR241B, Instruction Manual

Page: 107 / 272

ADR241B
Doc ID : ADR241B-DO_IM_01
Ref ID : ADR241B/IM/PLF
Rev No. : 06
Page No. : 107 of 272
4.10 Under Current Protection Function
Undercurrent condition is generally related to loss of load condition, whereby the system
current decreases in magnitude. If the regulating equipment is unsuccessful in restoring
healthy system current, Then the under current element is required to trip the circuit breaker
for the stable operation of Electrical power system.
The relay includes undercurrent element that can be used if the auxiliary contact of the CB
status connected to the relay is high i.e. when CBNO contact of CB is high.
4.11 Reclosing
Fault
52A
Reclose
td
time
Lockout
tr
Figure 17: Logic Diagram for reclosing logic
The ADR241B is provided with 4 shot Auto reclose function. There are 4 timer for auto
reclose 1) Dead Time for shot 1 (DT1) 2) Dead Time for shot 2 (DT2) 3) Dead Time for shot
3 (DT3) 4) Dead Time for shot 4 (DT4) and 5) Reclaim Time (RT). After clearing of fault
ADR241B trigger dead Time 1 i.e. DT1. After the time delay Relay provides reclose
command and start reclaim timer RT. If second fault occurs during RT relay triggers Dead
Time 2 i.e. DT2. If third fault occurs during RT relay triggers Dead Time 3 i.e. DT3, If Fourth
fault occurs during RT relay trigger Dead Time 4 i.e. DT4 and after time delay it again
provide reclose command and retrigger RT. If fifth fault occur during RT Relay generate
Lock-Out alarm and block further reclose. The Lock-Out condition can be reset locally as well
remotely by SCADA through communication digital status input.