Basler Electric DGC-2020 - Manual (Page 366)

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WATT DEMAND: This is the normalized requested kW demand on the generator. It is normalized
such that 1.0 indicates the full kW capacity of the generator, 0.5 indicates 50% of the generator’s
capacity, etc. When the generator breaker is closed, and the kW controller is enabled, the WATT
DEMAND indicates what level of power should be generated. In an island load share system, this
will correspond to the normalized value read on the load share lines. If the load share lines are at
the 50% point of the load share voltage range, the WATT DEMAND will be 0.5. If the generator
breaker is closed, and the PARALLEL TO MAINS logic element is true, the WATT DEMAND will
be equal to the base load set point. When the generator breaker is open or the kW controller is
disabled, the WATT DEMAND will always be equal to the value calculated from the voltage that
the LSM-2020 sees on its load share line.
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SPEED PID: This is the output value of the SPEED PID controller. It will normally range between
–1.0 and 1.0, and will be zero any time the generator breaker is open, unless synchronization is
in progress. If the Speed Trim is enabled, the SPEED PID will be nonzero when the generator
breaker is closed if there is any difference between the machine speed and the Speed Trip Set
Point parameter.
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kW PID: This is the output value of the kW PID controller. It will normally range between –1.0 and
1.0, and will be zero any time the generator breaker is open. If the kW Controller is enabled, the
kW PID will be nonzero when the generator breaker is closed if there is any difference between
the normalized kW generation and the WATT DEMAND value of the machine. If the kW controller
is disabled, the kW PID will always be zero.
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SPEED ERR: This is the normalized difference between the measured generator frequency and
the Speed Trip Set Point. A value of 1.0 means the difference is equal to the speed trip set point;
a value of –1.0 means the difference is equal to the negative of the speed trim set point. When
the generator breaker is open, or if Speed Trim is disabled, this will always be 0.000 unless
synchronization is in progress. When speed trip is enabled, and the generator breaker is closed,
this will typically be 0.000 or some relatively small number and move a small amount above and
below 0.000 as the speed trim controller corrects for any speed errors.
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kW ERROR: This is the normalized difference between the measured generator kW generation
and the WATT DEMAND described above. A value of 1.0 means the difference is equal to the
Rated kW of the machine; a value of –1.0 means the difference is equal to the negative of the
Rated kW of the machine. When the generator breaker is open, or if kW control is disabled, this
will always be 0.000. When kW control is enabled, and the generator breaker is closed, this will
typically be 0.000 or some relatively small number and move a small amount above and below
0.000 as the kW controller corrects for kW errors. If a load is added or dropped from the system,
the error will be nonzero until the kW controller brings the kW generation to the desired level.
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SPEED BIAS: This is the normalized value to which the governor analog bias output of the LSM-
2020 will be driven to accomplish desired kW and speed trim control. It is equal to the sum of the
kW PID and the SPEED PID. If the value is –1.0, the speed bias output will be driven to the
minimum value of the governor bias output range. If the value is 1.0, the output will be driven to
the minimum value of the governor bias output range. If the value is 0.00, the output will be driven
to the midpoint value (i.e. half way between maximum and minimum values) of the governor bias
output range. If the generator breaker is open, or if the generator breaker is closed and speed
trim and kW control are disabled, the SPEED BIAS value will be 0.00, driving the bias output to
the midpoint of the governor bias output range indicating the generator should run at rated speed.
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PF SETPOINT: This is the power factor setpoint that will be used by the kvar controller when it is
in the Power Factor regulation mode.
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kvar RAMP: This indicates the current kvar ramp direction as NONE, UP, or DOWN.
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var RAMP DEMAND: This is the normalized var demand that is ramped from the initial var
loading upon generator breaker closure to the desired var output. The rate at which the ramp
occurs is set by the Ramp Rate (%) parameter in the AVR Bias Control settings. Note the rate is
in terms of percentage of machine capacity, it is not the time to ramp from zero up to the current
desired var level. Thus, at low var loading it may appear that the ramp is skipped. If the system is
loaded to only 10% and a unit is brought on line, and the load rate is 10% per second, it takes
only one second to be up to 10% so the ramp time may be short.
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var DEMAND: This is the normalized requested kvar demand on the generator. It is normalized
such that 1.0 indicates the full kvar capacity of the generator, 0.5 indicates 50% of the generator’s
capacity, etc. When the generator breaker is closed, and the var/PF controller is enabled, the var
8-12 DGC-2020 Maintenance and Troubleshooting 9400200990 Rev X