Functions
116
7UM62 Manual
C53000-G1176-C149-3
Figure 2-57
Logic Diagram of the Reverse Power Protection
2.15.2 Setting Hints
General
The reverse power protection is only effective and accessible if this function was set
within the framework of the protective function configuration (section 2.2, address
,
=
Enabled
. Set
Disabled
if the function is not required.
The address
, serves to switch the function
ON
- or
OFF
or to
block only the trip command (
Block Relay
).
In case of a reverse power, the turbine set must be disconnected from the system as
the turbine operation is not permissible without a certain minimum steam throughput
(cooling) or, in case of a gas turbine set, the motor load would be too heavy for the
network.
Pick-Up Values
The level of the active power input is determined by the friction losses to be overcome
and are situated in the following range, depending on the individual system:
•
Steam turbines: P
Reverse
/S
N
≈
1 % to 3 %
•
Gas turbines: P
Reverse
/S
N
≈
1 % to 3 %
•
Diesel drives: P
Reverse
/S
N
> 5 %
The setting can be acquired through a primary test. The reverse power should be
measured with the relay (Section 3.4.10.2). The user should select a setting of 0.5
times the value of the measured motoring energy. This value can be found at the per
cent operational measured values. The feature to correct angle faults of the current
and voltage transformers should be used especially for very large machines with a
particularly low motoring energy (see sections 2.3 and 3.4.10.2).
The pickup value
is to be set in percent of the secondary rated
apparent power.
FNo.05083
FNo.05086
&
&
FNo. 05096
FNo. 05092
FNo. 05097
FNo. 05098
Tripping
matrix
TMin
TRIP CMD
