Woodward GCP-30 Series User Manual

Manual 37365A GCP-30 Series Packages - Genset Control
© Woodward Page 65/179
General
Formula G: Start of the engine
[(generator rated power)(number of closed GCBs) – isolated reserve power] / number of closed GCBs =
generator power level that a generator is started
Formula H: Stop of the engine
(number of generators needed for load – 1 generator)(generator rating) – isolated reserve power – genera-
tor hysteresis = generator power level that a generator is stopped
Example
Two generators are in an isolated parallel operation application. One generator will always be in operation. The
second generator is used to share large loads.
Generator rating
= the power rating for an individual generator (all generators used in this application must be of
the same power rating). "Rated power generator" (Parameter 21) should be configured as "200 kW".
Generat
or rating = 200 kW
Number of closed GCBs
= all generator that are used to calculate available generation power must have their cir-
cuit breaker closed.
Number of closed GCBs = varies
Isolated reserve power
= the real load that a generator or generators are able to absorb while the next generator is
started. The reserve power is usually configured as the largest load swing that a power plant may encounter dur-
ing the time it takes to bring an additional generator online. "Reserve power isol.op." (Parameter 103) should be
confi
gured as "60 kW".
Isolated reserve power = 60 kW
Generator hysteresis
= the power level that a stop command will be issued
This value is calculated by subtracting the minimum generator load for a shut down command to be issued from
the minimum load that a start command is issued. In this example the calculation would be [60 kW – 30 kW =
30 kW]. "Hysteresis add on / off op." (Parameter 100) should be configured as "30 kW".
Generat
or hysteresis = 30 kW
Case 11:
An engine start command is issued to the second generator when the monitored system power reaches a specified
level. Formula G is used as follows:
[(generator rating)(number of closed GCBs) – isolated reserve power] / number of closed GCBs = generator
power level that a generator is started
(200 kW)(1) - 60 kW/1 = 140 kW
The generator that is providing power has a total load rating of 20 0kW (20 0kW x 1). The online generator has
an available load of 140 kW (200 kW – 60 kW). When the online generator load exceeds 140 kW, the second
generator will be started and brought online to share the load.
Case 12:
An engine stop command is issued to a generator when the monitored system power falls to a specified level.
Formula H is used as follows:
(
Number of generators needed for load – 1 generator)(generator rating) – isolated reserve power – generator hys-
teresis = system power level next generator stopped 400 kW - 60 kW - 200 kW - 30 kW = 110 kW
system power level / number of closed GCBs = individual generator load level
110 kW / 2 = 55 kW
The two generators providing power have a total load rating of 400 kW (200 kW x 2). Before a generator can be
shut down as the load decreases, the generator that will remain online must be able to sustain the remaining load.
This requires that the above formula be used to determine the load level that a shutdown command is issued. Ac-
cording to the calculations above that level is 110 kW. This load is shared equally among the online generators.
To determine the individual generator load levels the shut down power level must be divided by the number of
generators online (110 / 2 = 55 kW). When the individual loads for the generators drop below 55 kW, a stop
command will be issued and a generator will shed its load to the remaining generator, open its GCB, and shut
down.

Woodward GCP-30 Series Specifications

General

Brand	Woodward
Model	GCP-30 Series
Category	Controller
Language	English