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WOODWARD 8200-1310 (505D) | Steam Turbine Digital Control Series
Source: | Author:kongjiang | Published time: 2026-10-20 | 18 Views | 🔊 Click to read aloud ❚❚ ▶ | Share:
WOODWARD 8200-1310 (505D) | Steam Turbine Digital Control Series

WOODWARD 8200-1310 (505D) | Steam Turbine Digital Control Series
This chapter is provided to give users an idea of the 505 Digital Control's capabilities and how to apply

them to a system. Typical applications are schematically shown and their functionality explained. Programming and Start/ Run mode notes are given for each application to assist application programmers in configuring the 505 for their application. Basic peripheral device connections are shown in each application drawing to allow an understanding of how these devices interface to the 505 and expand system capabilities.

WOODWARD 8405-039 / 8405039 

WOODWARD 8271465D / 8271465D 

WOODWARD 5466-351 / 5466351 

WOODWARD 5466-333 / 5466333 

WOODWARD 5466-1035 / 54661035

Speed/Load PID: The Speed PID can control and limit:

•Unit Speed/Frequency
•Unit Load
The 505's Speed PID can be used to control unit speed/frequency when isolated and unit load when paralleled to an infinite bus (utility). The Speed PID can be programmed to sense unit load via its actuator output signal or a 4–20 mA analog input signal from a generator power sensor. When programmed to sense and control generator load via an analog input, true unit load is sensed and controlled. By using the generator load signal to control from, any turbine inlet or exhaust pressure variation is sensed and compensated for, thus providing true load control.
A combination of the Speed PID and its setpoint limits allows this PID to limit unit load. When used as a unit load limiter, it is recommended that the 505 be configured to sense and control only true generator load. If applying the 505 system to a soft grid (utility frequency varies greatly), it is recommended that unit load limiting be performed by the Auxiliary PID, not the Speed PID.
Auxiliary PID: The 505's Auxiliary PID can be programmed to control or limit:
•Turbine Inlet Steam Pressure
•Turbine Inlet Steam Flow
•Turbine Exhaust Steam Pressure
•Turbine Exhaust Steam Flow
•Generator Power output
•Plant or Tie line Import/Export Power
•Process Temperature
•Compressor Suction Pressure
•Compressor Suction Flow
•Compressor Discharge Pressure
•Compressor Discharge Flow
•Any process parameter related to unit load, inlet pressure/flow, or exhaust pressure/flow(depending on configuration)
The Cascade PID is cascaded with the Speed PID to vary unit speed/load. By directly positioning the Speed PID's setpoint, the Cascade PID can vary unit speed/load to control its input parameter. This configuration allows for bumpless transfers between the two control modes (Speed/Load and Cascade).
Operator Interface
Introduction
Interface to the control may be performed through the 505's service panel (located on the front of the control), remote switch contacts, analog inputs, meter readouts, relays, or a Modbus communications line to an operator interface device.
Graphical Display and Key Inputs
The control's service panel consists of hard key command buttons, soft key command buttons, and a Graphical User Interface screen.
The system operator uses the service panel to communicate with the 505 system. The service panel can be used only occasionally to communicate with the system, or it can continuously monitor user interface pages for the operator to view.
Service Panel Modes and User Levels
The 505 Service Panel operates in several modes and access user levels, each of which has a different.
purpose. The modes are: OPERATION, CALIBRATION, and CONFIGURATION. To enter and
exit a particular mode, the user must be logged in with an appropriate user level. These user levels are:
MONITOR, OPERATOR, SERVICE, and CONFIGURE. In addition to granting authority to enter and exit
modes, user levels also determine what parameters the user is authorized to adjust. See Table 11-1,
Mode Access by User Level.
Mode Descriptions
The OPERATION mode is the only mode that can be used to run the turbine. This is the default mode. Exiting CALIBRATION or CONFIGURATION mode will return to OPERATION mode. User levels: Operator, Service, or Configure.
The CALIBRATION mode is used to force signal outputs in order to calibrate signals and field devices. In this mode, the actuator, analog, and relay outputs can be manually controlled. To enter this mode, the turbine speed must be shut down with no speed detected. User levels: Service or Configure.
The CONFIGURE mode is used to set up the parameters for a specific application prior to operation of the unit. To enter this mode, the turbine speed must be shut down with no speed detected. When the unit enters CONFIGURE mode, the control is placed in IOLOCK, which will disable all Output I/O channels. If the control is not shut down, navigating through the configuration pages will allow viewing of CONFIGURE, but will not permit any changes to be made.
User Level Descriptions
The Monitor user level is view-only access. All commands from the front panel are inhibited. All values displayed on each screen are continuously updated.
The Operator user level allows for control of the turbine. Front panel commands to start, change setpoints, enable/disable functions, and stop the turbine are accepted.
The Service user level allows the same commands as the Operator user level plus tuning of Service menu parameters and issuing of additional commands.
The Configure user level allows the same commands and access as the Service user level plus tuning of Configuration menu parameters.
Adjusting Values
To adjust a value, you first navigate the In-Focus highlighter to the correct value – then use the green Adjust Key to raise or lower the value.
The ADJUST arrows will change a selected Service parameter by 1%. Using the ADJUST arrows in combination with the SHIFT key will change the service parameter by 10%. The view of the Adjust button icon next to the value will change to show the up/down arrows as filled when the SHIFT key is pressed.
Understanding PID Settings
Overview
The Speed, Cascade, Auxiliary (1 & 2), and Acceleration controls utilize PID controllers. The response of each control loop can be adjusted for optimum response; however, it is important to understand what a PID controller is and the effect each controller adjustment has on the controller response. Proportional gain, integral gain (stability), and DR (speed derivative ratio) are the adjustable and interacting parameters used to match the response of the control loop with the response of the system. They correspond to the P (proportional), I (integral), and D (derivative) terms, and are displayed by the 505 asfollows：
•P = Proportional gain (%)
•I = Integral gain (%)
•D = Derivative (determined by DR and I)
Proportional Control
Proportional response is directly proportional to a process change.
Analogy: Setting the hand throttle to keep a constant speed on a straight and level road.
Proportional control (using the same analogy) results in a certain speed as long as the car is not subjected to any load change, such as a hill. If the throttle is set to a particular setting, the car's speed remains constant as long as it stays straight and level. If the car goes up a hill, it will slow down. Of course, going down a hill, the car would gain speed.
Integral Control
Integral compensates for process and setpoint load changes.
Analogy: Cruise control maintains constant speed regardless of hills.
Integral, sometimes called reset, provides additional action to the original proportional response as long as the process variable remains away from the setpoint. Integral is a function of the magnitude and duration of the deviation. In this analogy, the reset response would keep the car speed constant regardless of the terrain.
Derivative
Derivative provides a temporary over-correction to compensate for long transfer lags and reduces stabilization time on process upsets (momentary disturbances).
Analogy: Accelerating into a high-speed lane with merging traffic.
Derivative, sometimes called "preact" or "rate", is very difficult to draw an accurate analogy to, because the action takes place only when the process changes and is directly related to the speed at which the process changes. Merging into high-speed traffic of a freeway from an "on" ramp is no easy task and requires accelerated correction (temporary overcorrection) in both increasing and decreasing directions. The application of brakes to fall behind the car in the first continuous lane or passing gear to get ahead of the car in the first continuous lane is derivative action.