Functions
2.18 Forward Active Power Supervision (ANSI 32F)
SIPROTEC, 7UM62, Manual
C53000-G1176-C149-7, Release date 03.2010
150
2.18.2 Setting Notes
General
Forward active power protection is only effective and available if this function was set during protective function
configuration (Section 2.4, address 132, FORWARD POWER is set to Enabled). If the function is not required
Disabled is set. The address 3201 FORWARD POWER serves to switch the function ON or OFF or to block only
the trip command (Block relay).
Pickup Values, Time Delays
The setting of the forward power protection depends strongly on the intended purpose. General setting guide-
lines are not possible. The pickup values are set in percent of the secondary apparent power rating S
Nsec
= √3
· U
Nsec
· I
Nsec
. Consequently, the machine power must be converted to secondary quantities:
with
P
sec
Secondary power corresponding to setting value
S
Nsec
secondary nominal power = √3 · U
Nsec
· I
Nsec
P
Mach
Machine power corresponding to setting value
S
N, Mach
Nominal apparent power of the machine
U
N Mach
Nominal voltage of the machine
I
N Mach
Nominal current of the machine
U
N prim
Primary Nominal Voltage of the voltage transformers
I
N prim
Primary nominal current of the current transformer
Address 3202 serves to set the threshold of the forward power to an undershoot (Pf<) and address 3203 (Pf>)
serves to set it to overshoot. Addresses 3204 T-Pf< and 3205 T-Pf> serve to set the associated time delays.
In address 3206 MEAS. METHOD the user can select whether a fast or a precise measuring procedure is to be
used for the forward power calculation. In most cases, the precise measuring procedure is preferred in the
power station sector (as a rule), whereas the fast procedure is applied for use as mains decoupling.
The set times are additional delay times not including the operating times (measuring time, dropout time) of the
protective function.