Areva MiCOM P921 - Page 119

Technical Guide P92x/EN FT/E11
User Guide
MiCOM P921-P922-P923 Page 41/110
[27] tV<=
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
[27] V<<=
NO
Description : configuration of the 2
nd
undervoltage stage
Range : NO / AND / OR
Note : if disabled (« NO » selected), all the following messages
are invisible, until « V<<< » message.
[27] V<<=
5.0 V
Description : setting of the 2
nd
undervoltage stage
Range : range 57-130V : 5-130V step = 0.1V
range 220-480V : 20-480V step = 0.5V
[27] tV<<=
10 ms
Description : time delay setting for the definite time curve.
Range : 0 – 599s, step = 0.01s
Note : definite time delay only for this stage
[27] V<<<=
NO
Description : configuration of the 3
rd
undervoltage stage
Range : NO / AND / OR
Note : if disabled (« NO » selected), all the following messages
are invisible, until the heading of the menu
[27] V<<<=
5.0 V
Description : setting of the 2
nd
undervoltage stage
Range : range 57-130V : 5-130V step = 0.1V
range 220-480V : 20-480V step = 0.5V
[27] tV<<<=
10 ms
Description : time delay setting for the definite time curve.
Range : 0 – 599s, step = 0.01s
Note : definite time delay only for this stage
[27] HYSTERESIS =
1.02
Description : setting of the HYSTERESIS element
Range : 1.02 – 1.05 step of 0.01
10.2 Overvoltage protection
10.2.1 Description
This function can be configured according to the connection scheme of the VTs :
phase-phase (delta connection) or phase-neutral protection (star connection).
For this overvoltage protection, the configuration can also be done in order to have :
· the highest voltage of each phase will be decisive : select OR for the considered
stage,
· each voltage for each phase must be higher than the settable stage : select AND
for the considered stage.
The settings of the voltage thresholds are done in secondary values.
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 and third stage.
The inverse characteristic is given by the following formula :
t = K / (M - 1)
Where, K = Time Multiplier Setting
t = operating time in seconds
M = Applied input voltage / Relay setting voltage (Vs).