Category: Woodward

Fuel Flow

Gas fuel flow is normally achieved by the accurate scheduling of the metering valve port area, based on

values for gas properties, operating pressures, and temperature. The GS-Series valve is factory calibrated

under flow and pressure conditions to provide an accurate valve metering to the input demand signal.

Flow equations for the valves are located in the O&M manual. These can be used to set up the valve for

any site-specific conditions.

Port Sizes

The GS-Series is available with five different port sizes to optimize valve performance for various flow and

pressure drop requirements. Standard port effective area sizes are:

GS40

• 0.30 in² (193.5 mm²)

• 0.75 in² (483.9 mm²)

GS50

• 1.0 in² (645.2 mm²)

• 1.5 in² (967.7 mm²)

• 2.0 in² (1290.3 mm²)

The standard metering ports are contoured to provide approximately square law relationships between

commanded position and effective area.

The on-board valve driver performs the following functions:

• Fast and accurate closed loop position control of the gas valve in response to the 4–20 mA or

CANopen/RT

Ethernet input command signal

• Actual valve position feedback via 4–20 mA or CANopen/RT Ethernet

• Independent remote shutdown input

• Valve/driver fault output

The driver includes protection and alarm indications for the following faults:

• Analog input out of range

• Feedback—open wire and short

• Input power out of range

• Position error

• Internal driver faults

• Actuator open/short

• Driver overcurrent

All faults are available through the CANopen/RT Ethernet connection or through an Ethernet Service

connection.

On-board Driver

The valve driver and wiring terminal box are integral with the valve assembly,

eliminating interconnecting wiring, reducing package size requirements, and

lowering the installed cost. The on-board driver can be interfaced to the turbine

control via redundant 4–20 mA input and feedback signals, through redundant

CANopen control networks, or through redundant real-time Ethernet networks. The

GS-Series can be configured to accept both the 4–20 mA signal and CANopen/RT

Ethernet position command in a redundant configuration. With this arrangement, if

either demand signal fails, the driver will switch to the healthy input demand signal.

The valve driver operates with a 90-150 VDC or 18-32 VDC power supply,

depending on the model.

Description

The GS-Series is an electrically actuated fuel valve with an on-board electronic

driver. The self-cleaning, shear-type metering action keeps the metering port free

from performance-limiting deposits of gas condensates, contaminants, and system

debris. The valve minimizes the moving parts within the fuel metering element,

actuator rotor, and redundant position feedback resolvers to maximize accuracy over

the entire operating range. Available actuator torque has been increased to provide

more robust performance in the harshest conditions. Accurate flow versus input

signal characteristics is achieved on each valve version by precision forming of the

valve metering port, the use of extended valve travels, and high precision resolvers

for valve position feedback. The GS valves can achieve flow turn-down ratios in

excess of 100 to 1. The positive flow shut-off rating meets the requirements of ANSI

B16.104 Class IV across all valve sizes and ports.

• Electric actuation

• Integrated driver

• Robust self cleaning valve

• Aluminum or stainless steel body

• Multiple trim sizes available

• -40°F to 350°F fuel range

• Fuel pressures to 1440 psig

• SAE and ANSI RF flange options

• 24 VDC or 125 VDC input voltage options

• IIoT ready

• Analog and digital I/O

• Models available with CE Marking to applicable directives, with IECEx

Certification to Hazardous Locations, and North America

• 100% Hydrogen Compatible Model Available

Applications

The Woodward GS Series gas fuel metering valve

family is the latest version of rotary control valves

utilizing an integrated actuator and on-board driver

built on decades of application experience in the

gas turbine market.

The self-cleaning valve design is ideal for applications ranging from clean pipeline

gas to wellhead gas. The valve features an on-board electric actuator driver for

ease of packaging and installation. The on-board driver eliminates the need for

costly climate-controlled terminal boxes and associated cabling. Each valve

includes redundant position feedback resolvers and an integral failsafe spring to

maximize reliability and safety. The integrated driver incorporates redundant signal

conditioning, fault detection, and selectable failure management options. The

multiple valve sizes and trims can be configured in single or multi-path systems to

enable a wide range of applications.

DSLC-2 / MSLC-2 Systems

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The network addressing of the DSLC-2 / MSLC-2 allows up to 32 DSLC-2s and 16 MSLC-2s in an ap

plication. A DSLC-2 and MSLC-2 application can handle 8 segments. Discrete inputs inform the DSLC

2s and MSLC-2s which segments each generator and utilities are operating on. If a MSLC-2 receives a

discrete input to activate segment 1 and 2. it will share this information with all controls over the Ether

net bus. It is not necessary to provide a segment activation discrete input to all controls. Segmenting

allows the DSLC-2s and MSLC-2s to remain connected thru the Ethernet bus, but be operating on sep

arate load buses.

The DSLC-2 / MSLC-2 system can be applied according to following rules:

• The maximum number of DSLC-2s (Gen-CB) is 32.

• The maximum number of MSLC-2s (Utility- or Tie-CB) is 16.

• The maximum number of segments is 8.

• The segment numbers have to follow a line, which can finally be closed to a ring.

• For DSLC-2 it can be selected between two segmenting modes:

o Bus segmenting determining generators running together via an algorithm.

The DSLC-2 / MSLC-2 system can be applied according to following rules:

• The maximum number of DSLC-2s (Gen-CB) is 32.

• The maximum number of MSLC-2s (Utility- or Tie-CB) is 16.

• The maximum number of segments is 8.

• The segment numbers have to follow a line, which can finally be closed to a ring.

• For DSLC-2 it can be selected between two segmenting modes:

o Bus segmenting determining generators running together via an algorithm.

o Device segmenting determining generators running together from outside.

• Only one MSLC-2 can be used as master control, when multiple MSLC-2 is resided in one segment.

o The MSLC-2 with the lower device number will control if multiple Utility MSLC-2s are

active on the same segment

• The generator is not counted as a segment.

• The utility is not counted as a segment.

Var/PF Control

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The var/PF function controls the power factor on all of the DSLC-2 equipped machines operating in

isochronous load sharing. The PF control begins on breaker closure. The MSLC-2 has three modes of

Var/PF control (which are selected in Menu 4):

• Constant generator power factor – sets the power factor reference on all of the DSLC-2 con

trols to the internal reference chosen in the MSLC-2. The power factor can then be adjusted

using the voltage raise and lower inputs. The voltage raise command will make the power fac

tor more lagging. Conversely, the voltage lower command will make the power factor more leading.

• Utility tie power factor control – adjusts the power factor reference on all of the DSLC-2 con

trols in isochronous load sharing in order to maintain the power factor across the utility tie.

• Utility tie var control – adjusts the power factor reference on all of the DSLC-2 controls in

isochronous load sharing in order to maintain the level of vars being imported or exported from the

utility.

The var/PF control mode begins with the load control mode selected. The constant generator power

factor and the utility tie power factor control can have the reference setting controlled by an analog in

put (see Menu 6). By closing the voltage raise and lower discrete inputs, you can select the analog re

mote input for reference control.

The MSLC-2 is not capable of overloading or reverse powering the generators in an attempt to meet

the process reference. The high and low limit switches mentioned above can be used to indicate that

either too many or too few generators are online to maintain the process within its limits.

A process controller is provided for cogeneration, fluid level maintenance, pressure control or other ap

plications. An adjustable bandwidth signal input filter, flexible PID controller adjustments, selectable for

direct or indirect action, allow the process control to be used in a wide variety of applications.

An analog signal input (signal variety: 0 to 20mA, 4 to 20mA, 0 to 5V, 1 to 5V and 0 to 10V) provides

the process signal to the MSLC-2. The MSLC-2 includes an internal digital process reference, which

may be controlled by the raise and lower switch contact inputs or by an external analog input signal as

remote process reference. The MSLC-2 also has a Modbus address for process reference control. The

output of the process control, like the import/export control, is the percentage of rated load setpoint to

the individual generators in isochronous load sharing.

Process Control

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A process controller is provided for cogeneration, fluid level maintenance, pressure control or other ap

plications. An adjustable bandwidth signal input filter, flexible PID controller adjustments, selectable for

direct or indirect action, allow the process control to be used in a wide variety of applications.

An analog signal input (signal variety: 0 to 20mA, 4 to 20mA, 0 to 5V, 1 to 5V and 0 to 10V) provides

the process signal to the MSLC-2. The MSLC-2 includes an internal digital process reference, which

may be controlled by the raise and lower switch contact inputs or by an external analog input signal as

remote process reference. The MSLC-2 also has a Modbus address for process reference control. The

output of the process control, like the import/export control, is the percentage of rated load setpoint to

the individual generators in isochronous load sharing.

An adjustable ramp allows smooth entry and exit from the process control mode. When the process

control mode is selected, the load reference is ramped in a direction to reduce the error between the

process input and the process reference. When the error is minimized or the reference first reaches

either the high or the low specified limits, the process controllers PID loop is activated. When the load

reference output reaches either 100% or 0%, the control will maintain that load reference until process

control is established.