Forward Active Power Supervision (ANSI 32F)
119
7UM62 Manual
C53000-G1176-C149-3
2.16
Forward Active Power Supervision (ANSI 32F)
General
The machine protection 7UM62 includes an active power supervision which monitors
whether the active power falls below one set threshold, and whether a separate
second set threshold is exceeded. Each of these functions can initiate different control
functions.
When, for example, with generators operating in parallel, the active power output of
one machine becomes so small that other generators could take over this power, then
it is often appropriate to shut down the lightly loaded machine. The criterion in this
case is that the “forward” power supplied into the network falls below a certain value.
In some applications it can be desirable to output a control signal if the active power
output rises above a certain value.
For example, an industrial network which has certain measures of its own generation
is coupled via a coupling circuit breaker with a HV utility network and should be
decoupled when a fault in the utility network is not cleared within a critical time. As a
criterion for decoupling, underfrequency, undervoltage, overcurrent, power direction,
or combinations of these can be used. As a result, the 7UM62 can also be used for
network decoupling.
2.16.1 Functional Description
Active Power
Measuring
For power measurement, two measurement methods are available. Depending on the
application either high-speed measurement or high-accuracy measurement (average
about 16 cycles) may be selected. High-speed measurement is suitable e.g. for
network decoupling.
The device calculates the active power from the positive sequence systems of the
generator currents and voltages. This value is compared with the set values. Each
stage can be blocked individually, as can be the complete forward active power
supervision, via binary inputs.
Figure 2-58 shows the logic diagram of the forward active power supervision.
Figure 2-58
Logic Diagram of the Forward Active Power Supervision
FNo. 05117
FNo. 05113
&
FNo. 05126
FNo. 05128
FNo. 05129
Tripping
matrix
FNo. 05122
FNo. 05116
FNo. 05127
&
TMin
TRIP CMD