Areva MiCOM P921 - Page 125

Technical Guide P92x/EN FT/E11
User Guide
MiCOM P921-P922-P923 Page 47/110
10.5 Positive sequence undervoltage protection (MiCOM P922 and P923)
The relay will trip according to an inverse characteristic or a definite time
characteristic for the first stage and according to a definite time characteristic for the
second stage.
The inverse characteristic is given by the following formula :
t = K / (1 – M)
Where, K = Time Multiplier Setting
t = operating time in seconds
M = Applied input voltage / Relay setting voltage (Vs).
To gain access to the “POS SEQ U/V” sub-menu from the default display, press 2
once, 6 4 times, 2 once and 6 4 times.
[27D] POS SEQ U/V
Heading of the “POS.SEQ U/V” menu
[27D] V1<=
NO
Description : configuration of the 1
st
stage(V1<«
Range : YES/NO
Note : if disabled (« NO » selected), all the following messages
are invisible, until « V1< » message.
[27D] V1<=
5.0 V
Description : setting of the 1
st
stage
Range : range 57-130V : 5 – 130V, step = 0.1V
range 220-480V : 20 – 480V, step = 0.5V
[27D] DELAY TYPE =
DMT
Description : selection of the time delay characteristic
Range : definite time (DMT) / inverse definite time (IDMT)
[27D] TMS=
1.0
Description : time multiplier setting.
Range : 0.5 – 100, step = 0.5
Note : this message only seen if “IDMT” time delay selected
[27D] tRESET V1<=
10 ms
Description : reset time for the first positive undervoltage stage
Range : 0 – 100s, step = 0.01s
Note : this message only seen if “IDMT” time delay selected
[27D] tV1<=
40 ms
Description : time delay setting for a definite time curve.
Range : 0 – 599s, step = 0.01s
Note : this message only seen if “DMT” time delay selected
[27D] V1<<=
NO
Description : configuration of the 2
nd
stage(V1<<«
Range : YES/NO
Note : if disabled (« NO » selected), all the following messages
are invisible, until the heading of the sub-menu.
[27D] V1<<=
5.0 V
Description : setting of the 2
nd
stage
Range : range 57-130V : 5 – 130V, step =0.1V
range 220-480V : 20 – 480V, step = 0.5V
[27D] tV1<<=
40 ms
Description : time delay setting for the definite time curve.
Range : 0 – 599s, step = 0.01s
Note : definite time delay only for this stage