LEXE7567-02 Island Mode.pdf

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LEXE7567-02 (02/08)

G3500C Island Mode Transient Performance

Engine Class Definition

The information contained herein applies only to the Caterpillar G3516C and G3520C Gas engines equipped with the Island Mode Control System. The capabilities stated do not apply to the standard G3516C and G3520C engines.

Island mode operation as defined by Caterpillar is any Gas Generator Set operation that is not paralleled to a public utility. In this operational state the Gas Engine must maintain torque and crankshaft speed (bus frequency) during steady state operation. The Generator Voltage is maintained using a voltage regulator.

In Island Mode operation, increases in load cause the engine speed to decrease below the rated speed of the engine and then recover back to rated speed after a period of time. Decreases in load cause the inverse. The shape of the engine speed response or generator set frequency response to an application of load is generally a function of the amount of load being added or removed, as well as, the settings of the generator voltage regulator, speed governor gain settings, ambient conditions, fuel quality, and fuel characteristics. While the package emissions setting can affect engine speed response, the data provided in this document is valid for all emission settings available in the pricelist.

Engine Ratings

Engine Ratings are at standard conditions. Refer to TMI web for additional conditions and information for site specific gas engine ratings.

G3520C 1966 ekW at 1500 rpm G3520C 2055 ekW at 1800 rpm G3516C 1565 ekW at 1500 rpm

ISO Capability

The engines specified above have been tested against the voltage deviation, frequency deviation, and recovery time requirements defined in ISO 8528 - 5. At this time the engines stated above will meet class G1 transient performance as defined by ISO 8528 - 5. Loading and unloading diagrams meeting class 1 performance will be given below. Responses shown are based on resistive loading only. The class 1 requirements are shown here.

PPrroodduucctt UUppddaattee Transient Performance Conditions

Block Load Diagrams

Classification as Defined by ISO 8528 - 5

Dynamic Frequency Deviation

Frequency Recovery

Time

Dynamic Voltage Deviation

Voltage Recovery Time

Class G1 +18/-25 % 10 seconds +35/-25 % 10 seconds

Block load diagrams are provided to give information about the permissible load increases in effective power that can be obtained from a given percent of the rated effective electrical power output of the generator set.

Island Mode - Load Increases

0

5

10

15

20

25

30

0 10 20 30 40 50 60 70 80 90 100

Pelectrical actual (% of Pelectrical rated)

P ele

ctric

al in

crea

se

(% o

f Pel

ectr

ical

rate

d)

Class G1

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Block Unload Diagrams

Block load diagrams are provided to give information about the permissible load decreases that can be obtained with the specified engines from a given percent of the rated effective electrical power output of the generator set.

Island Mode - Load Decreases

0

5

10

15

20

25

30

0 10 20 30 40 50 60 70 80 90 100

Pelectrical actual (% of Pelectrical rated)

P ele

ctric

al d

ecre

ase

(% o

f Pel

ectr

ical

rate

d)

Class G1

Additional Transient Capability

The tables below provide additional definition for the transient capabilities of the engines specified herein. The transient capabilities stated below were developed through testing at Caterpillar facilities and do not fall under the transient performance class definitions as provided in the ISO 8528-5 document. The steady state (SS) values defined by this table assume less than or equal to a 1.5% fluctuation in load over 60 seconds. Load percentages are of the engine rating as defined by engine specific technical data. Specified responses pertain to both load application and removal. Responses shown are based on resistive loading only.

LEXE7567-02 (02/08)


LEXE7567-02 (02/08)

1st Load Step Dynamic Frequency

Dynamic Voltage

Recovery Time to SS

Deviation Deviation

25% 20 Sec +/- 16% +/- 12%

Load Step Dynamic Frequency

Dynamic Recovery Time

Deviation Voltage

Deviation to SS

25%* 10 Sec +/- 10% +/- 12%

10% +/- 5% +/- 3% 5 Sec

5% +/- 2.5% +/- 1% 5 Sec

SS +/- 1% +/- 1%

*Note: V for block loads e initial 25% ep

ite Conditions and Engine Derate

e are stated as a percentage of the engines full rated load as indicated in the appropriate performance technical data sheet. Site ambient

Fuel Pressure and Stability

tability is critical to transient performance. Proper installation requires that all fuel train components (including filters, shut off valves, and regulators) be

f

alid above th load st

S

The transient load steps listed abov

conditions, fuel quality, inlet/exhaust restriction and emissions settings will all affect engineresponse to load change. Island Mode engines that are not operating at the standardconditions stated in the technical data sheet should be set up according to the guidelines included in the technical data; applying timing changes and/or engine derates as needed.Adherence to the engine settings guidelines will allow the engines to retain the transient performance stated in the table above as a percentage of the site derated power (whereappropriate).

Fuel supply pressure and s

sized to ensure adequate fuel delivery to the engine. While the engine may be capable ooperating at lower fuel pressures, to meet the transient response specified in this document, higher fuel pressures will be required. The following are fuel pressure requirements to be measured at the engine mounted fuel valve.


LEXE7567-02 (02/08)

. Recommended Fuel Supply Pressure 20 kPa, g (2.9 psi)

St bility - 0.1 psi, g/sec)

must be maintained at 54C or 32C (depending on configuration) for all engines. It is important that the external cooling system design is able

Sta etween Load Steps

stem may require 2 to 3 minutes after a load step has been performed for NO to return to nominal setting. If the stabilization time is not met

Vo

ponse to load changes is closely related to the settings in the

Sp

a speed-governing algorithm embedded in the ADEM III ECM. Droop and Isochronous governors can be selected. Isochronous governing is

En

ed to start and stabilize at rated engine speed is a minimum of 1 minute after a successful crank cycle.

A

B. Max Fuel Supply Pressure 34.5 kPa, g (5 psi)

C. Steady State Fuel Pressure a +/- 6.9 mbar/sec (+/

D. Transient fuel Pressure Stability +/- 48.2 mbar/sec (+/- 0.7 psi, g/sec)

Separate Circuit After Cooler (SCAC)

Inlet water temperature to the SCAC

to maintain the inlet water temp to the SCAC to within +/- 1C during all engine-operating cycles. The SCAC inlet temperature stability criterion is to maintain stable inlet manifold air temperature.

bilization Time B

The charge density emissions control syx

between load steps ISO class G1 transient performance may not be met.

ltage Regulator Settings

Transient engine speed resgenerator voltage regulator. Changes to the volts/Hz, knee frequency, and regulator PID settings that may be required for site operation will cause the frequency and voltage response of the generator set to change.

eed Governor Settings

The G3500C engines use

recommended for Island Operation. Nominal Gain settings were used in all transient testing. Governor gains may need to be tuned for site conditions.

gine Starting

The time need


LEXE7567-02 (02/08)

ngine Condition

maintained in accordance to guidelines specified in the Caterpillar Service Manuals applicable to each engine. Wear of components outside of the specified

E

Engines must be

tolerances will affect the transient capability of the engine.

Information contained in this publication may be considered confidential. Discretion is recommended when distributing. Materials and specifications are subject to change without notice.

LEXE7567-02 (02/08) www.cat-electricpower.com

CAT, CATERPILLAR, their respective logos, Caterpillar Yellow and the POWER EDGE trade dress, as well as corporate and product identity used herein, are trademarks

of Caterpillar and may not be used without permission.

2008 Caterpillar All Rights Reserved.

Printed in U.S.A.

G3500C Island Mode Transient Performance

LEXE7567-02 Island Mode.pdf

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