Areva MiCOM P921 - Page 64

P92x/EN TD/E11 Technical Guide
Technical Data
Page 18/30 MiCOM P921-P922-P923
3.5.2 Time delay settings
Each voltage element is associated to an independent time delay.
Each measuring element time delay can be blocked by the operation of a user
defined logic (optical isolated) input (see “Blocking logic1” or “Blocking logic2”
functions).
Element Time delay type
1
st
stage Definite Time (DT) or IDMT
2
nd
stage DT
3.5.3 Inverse Time Delay Characteristic
The inverse characteristic is defined by the following formula :
÷
÷
÷
÷
÷
ø
ö
ç
ç
ç
ç
ç
è
æ
-
=
1
V
V
TMS
t
S
1
where :
t = operating time in seconds
TMS = time Multiplier Setting
V
1
= applied input voltage
Vs = relay setting voltage
Setting Range Step Size
TMS 0,5 - 100 0.5
Setting Range Step Size
tRESET (only DT) 0 – 100s 0.01s
3.5.4 Definite time delay characteristics
Setting Range Step Size
tV
1
< 0 – 599s 0.01s
tV
1
<< 0 – 599s 0.01s
3.5.5 Hysteresis
Hysteresis fixed 105%