Sices HS 315, Техническое руководство

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Technical Handbook 127
voltage status: this allows not to switch the loads on the generator if the electrical magnitudes
are out of the tolerance band, even though protections are disabled.
Thresholds P.0391 and P.0393 are used for protections only; they are not used for detecting
the status of the generator.
The DC voltage of the generator can be connected to terminals JH, JG or JQ (see 5.13).
To detect the status, normally the controller cannot use the DC voltage of the generator if it is
connected to other active sources, like the auxiliary source or the plant battery. In this case, in
fact, the measured voltage is an “average” of those connected. It is possible to by-pass the
problem in the following ways:
•
Connecting also the AC voltages.
•
Ensuring that the controller can measure the speed of the engine (pick-up, W, Can
Bus). In this way, the controller can check (at least) that the speed is between the
provided thresholds (it cannot check the DC voltage).
•
Ensuring that the controller can detect the engine running status not using DC voltage
(+D, oil pressure). In this way, the controller can check (at least) that the engine is not
stopped (it cannot check the DC voltage).
If no one of the previous methods can be used, the controller will activate the W237 warning
when it is not able to detect the status of the generator.
If the controller acquires the speed of the engine, it checks that it is inside the provided
thresholds. Wit is valid what we said about the AC frequency but referred to the engine nominal
speed.
Here follows an example about the various threshold used, including default values for a.m.
parameters.
Parameter Description Default value Speed (rpm)
P.0133 Engine's nominal speed
(primary).
1500 rpm 1500
P.0228 Threshold for engine stopped
(Hz). 10.0 % 150
P.0229 Threshold for engine started
(Hz). 20.0 % 300
P.0305 Minimum frequency threshold. 90.0 % 1350
P.0307 Maximum frequency
threshold.
110.0 % 1650
P.0331 Maximum speed threshold
(frequency). 120.0 % 1800
0 Hz .
A band: absent
150 Hz .
B band: hysteresis
300 Hz .
C band: minimum
1350 Hz .
D band: low
1351 Hz .
E band: in tolerance
1649 Hz .
F band: high
1650 Hz .
G band: Maximum