ABB REL650 series, Applications Manual

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(%) ( ) / 3 V VBase kV
> ×
EQUATION1713 V2 EN
(Equation 166)
and operation for phase-to-phase voltage over:
Vpickup (%) VBase(kV)
> ×
EQUATION1992-ANSI V1 EN
(Equation 167)
Characteristic1 : This parameter gives the type of time delay to be used. The setting can be.
Definite time/Inverse Curve A/Inverse Curve B/Inverse Curve C . The choice is highly
dependent of the protection application.
OpModen : This parameter describes how many of the three measured voltages that should
be above the set level to give operation for step n (n=step 1 and 2). The setting can be 1 out
of 3, 2 out of 3 or 3 out of 3 . In most applications it is sufficient that one phase voltage is
high to give operation. If the function shall be insensitive for single phase-to-ground faults
3 out of 3 can be chosen, because the voltage will normally rise in the non-faulted phases
at single phase-to-ground faults.
Pickupn : Set overvoltage operating value for step n (n=step 1 and 2), given as % of the
global parameter VBase . The setting is highly dependent of the protection application.
Here it is essential to consider the Maximum voltage at non-faulted situations. Normally
this voltage is less than 110% of nominal voltage.
tn : time delay for step n (n=step 1 and 2), given in s. The setting is highly dependent of the
protection application. In many applications the protection function has the task to prevent
damages to the protected object. The speed might be important for example in case of
protection of transformer that might be overexcited. The time delay must be co-ordinated
with other automated actions in the system.
t1Min : Minimum operating time for inverse time characteristic for step 1, given in s. For
very high voltages the overvoltage function, using inverse time characteristic, can give
very short operation time. This might lead to unselective trip. By setting
t1Min longer than
the operation time for other protections such unselective tripping can be avoided.
TD1 : Time multiplier for inverse time characteristic. This parameter is used for co-
ordination between different inverse time delayed undervoltage protections.
1MRK 506 334-UUS A
Section 8
Voltage protection
261
Application manual