TTM-AMM3-INST-Mod-01.pdf

Course Description Instruments Training Module-1 AMM-3 Course goal The goal of this course is to give the participants an overview of the major control systems at AMM-3. This course primarily focuses the control of Steam Turbines at EnVen plant covering the speed control, anti-surge control, and s...

Course Description Instruments Training Module-1 AMM-3 Course goal The goal of this course is to give the participants an overview of the major control systems at AMM-3. This course primarily focuses the control of Steam Turbines at EnVen plant covering the speed control, anti-surge control, and steam control systems. In addition to Theoretical knowledge, this course imparts hands-on experience of these control systems through OEM manuals and configuration sheets at EFERT. Topics Learning objectives x ProMistic Control System Upon completion of this course the participants x CCC A3 anti Surge Controller will be able to understand: x Peak® 150 Digital Control x Hydraulic Supply Unit x Steam Turbine Speed Control Systems x Steam Turbine Anti Surge Systems x Steam bypass and De-super Heater Course type and methods Control This is a self-study course with direct mentoring x Let Down Station ProMistic Control from an assigned senior instrument resource. Participant profile Duration This training is targeted for CL 21-23 based on area assignment of Instrument MPTs The duration is 16 weeks. Prerequisites The participants should be familiar with basic concepts of Steam Turbine Control Systems Page 1 of 2 Week-1 to 4: Woodward Peak 150 Week-9 to 12: ProMistic Control System Turbine Speed Control Concepts Peak 150 Wiring and Installation Basic Operation Functional Understanding Field Orientation Operating Procedures ProMistic Controller and associated drawings Programming the WW Peak 150 Controller Logic Review Site specific programming sheets and their P&IDs Review understanding Modification and User Levels Modbus Communication Hands on training on Software Trouble shooting Understanding of wiring drawings Servicing Understanding of logic Week-5 to 8: CCC A3 Anti-Surge Controller Week-13 to 16: Hands on Work at Systems Introduction to Surging in Centrifugal and axial flow compressors Woodward Peak 150 CCC training presentation CCC A3 Anti-Surge Controller Surge control algorithms CCC series 3 plus ProMistic Control System Basic P&IDs and Instrumentation CCC Series 3 plus Hardware CCC Series 3 plus operation using front Operator panel CCC configurations using engineering Panel Page 2 of 2 Tab ble of Coontents Ove erview of P Peak 150........................................................................................................................................... 5 App plications o of Peak 150 0..................................................................................................................................... 5 Ope eration............................................................................................................................................................... 5 Ope erating Mo odes.................................................................................................................................................. 6 Manual Mode e........................................................................................................................................................ 6 Rem mote Speed d Set Mode..................................................................................................................................... 6 mbination Mode.............................................................................................................................................. 6 Com Blocck Diagram m....................................................................................................................................................... 9 Com mmunicatio on.................................................................................................................................................... 9 What is a Surg ge?................................................................................................................................................. 24 Antti-Surge Co ontrol Syste ems.............................................................................................................................. 25 Antti-Surge Co ontroller Syystem And Algorithm ms............................................................................................ 25 Antti-Surge Syystem layou ut.................................................................................................................................. 28 Antti-Surge Va alve Specifiication......................................................................................................................... 29 Ove erview of LLet Down Station S.......................................................................................................................... 37 Let Down Stattion at Eferrt................................................................................................................................... 41 Ope eration Description........................................................................................................................................ 41 De--superheatting Spray Water W Valvve – Contro ol Descripttion...................................................................... 42 Link ks for Deta ailed Study..................................................................................................................................... 44 Page 1 of 2 List of Atta achmentts ak 150 Con Pea nfiguration Sheet........................................................................................................................................ 11 CCC urge....................................................................................................................... 30 C A3 Contrroller – Currves and Su CCC ntroller....................................................................................................................................... 35 C A3 Contrroller - Con Promistic Con ntroller – In nstrument and a Contro ol Schemattic........................................................................ 45 Promistic Con ntroller – Prromistic FH HMI............................................................................................................ 47 Promistic Con ntroller – Bu urnout Setttings......................................................................................................... 56 Page 2 of 2 Woodward Peak 150 Digital Control for Steam Turbines Overview The Peak® 150 digital control is a microprocessor-based control designed to control single-valve or single-valve rack steam turbines. A microprocessor-based digital control provides flexibility in configuring to your specific control requirements. This ability to configure your system in the field allows a single design to be used in many different control applications, and reduces both cost and delivery time. Applications The Peak 150 digital control is designed to control a steam turbine driving a mechanical load. It provides tight control of speed (NEMA D) and includes an input for a 4–20 mA remote speed control signal, which can be used for a process-generated input to control the speed setting. Other features include dual speed control dynamics and over-speed trip test capabilities. Operation The operation of the control is simple. To start the turbine, the steam-supply valve must be opened (manually or by other means). When the turbine comes up to the user-determined idle speed, the Peak 150 system takes control of the turbine—the steam-supply valve can then be opened fully. The Peak 150 control includes circuitry for detecting the loss of either MPU signal—this circuitry is automatically overridden for starting. The turbine can be accelerated from idle speed to minimum governor speed either automatically (by using the remote Idle/Min Gov contacts or by using the front panel start), or manually (by using the panel or remote Raise or Lower commands). Page 1 of 6 Operating Modes The Peak 150 control has three operating modes: manual mode, remote speed set mode, and combination mode. Manual Mode If the manual mode is configured, the turbine speed is adjusted solely by the front panel keys and the remote raise and lower discrete inputs. The remote speed setting analog input is ignored in this mode. Remote Speed Set Mode When the remote speed set mode is configured, the turbine speed is determined by the remote speed setting analog input. When the remote speed setting enable contact is closed and the turbine is at or above minimum governor speed, turbine speed will ramp from minimum governor speed to the remote value at a user-defined rate. Once the speed set point output matches the setting of the remote speed setting signal, the speed will change at a new user-defined rate for process control. If the remote speed setting signal is disabled for any reason, the speed set point will remain at the last speed and the set point adjustment operates as it does in manual mode. Combination Mode The combination mode is similar to the analog remote speed set mode, except that the speed demand generated by the discrete (front panel and remote raise and lower contact inputs) and the analog remote speed setting signal are compared for the highest value. This highest value is passed on as the commanded speed. If the remote speed setting signal is disabled for any reason, control of the speed set point operates as it does in manual mode. Programming Unit A small hand-held programmer (see illustration) connects to the Peak Page 2 of 6 150 to permit system configuration and tuning. System constants cannot be changed without this unit, so unauthorized changes are easily prevented by limiting access to the programmer. Critical Speed Avoidance To protect the turbine and skid from excessive vibration, a critical speed band can be defined by the user. While within this band, turbine speed will change at a fast rate (user-defined) and cannot be stopped within the band Specifications Inputs Pickup Inputs (2) Two identical inputs, high-signal-selected Minimum input voltage 1 Vrms, minimum frequency 200 Hz, maximum frequency 15 kHz Analog Input (1) Remote Speed Setting signal (4–20 mA or 1–5 Vdc, internal jumper selectable) Discrete Inputs (8) Remote (isolated, 5–28 Vdc) Options Raise speed Lower speed Emergency stop Alarm reset Remote speed set enable Start Idle/minimum governor Select high dynamics or over-speed test Outputs Analog Outputs (2) Actual speed output (scalable, 4–20/0–1 mA) Configurable readout (scalable, 4–20/0–1 mA) Options Actual speed Speed setpoint Actuator output Remote speed setpoint Valve ramp value Page 3 of 6 Actuator Output (1) 4–20 or 0–200 mA (internal jumper selectable) Relay Outputs (4) Internal jumpers provide choice of normally-open or normally-closed Contacts Contact ratings are 2 A resistive @ 28 Vdc 0.3 A resistive @ 115 Vac Shutdown (de-energizes or energizes for shutdown) Alarm (de-energizes for alarm) Configurable Relay #1 Configurable Relay #2 Options Alarm Trip output Shutdown Remote control Speed control MPU failure Overspeed trip Overspeed test Remote signal OK Speed switch #1 Speed switch #2 Hand valve #1 Hand valve #2 Operator Control Panel Keypad Switches (6) Options Raise speed Lower speed Emergency trip Start Overspeed test Alarm reset LED Indicators (6) Remote speed setting signal status Shutdown status MPU #1 status MPU #2 status CPU status Overspeed test status Digital Display Five-digit LED speed display Page 4 of 6 Block Diagram Communication Serial communication using the Modbus® * protocol is an option on the Peak 150. The transmission mode can be configured to be either RTU or ASCII mode. RS-232, RS- 422, and RS-485 will all be supported through wiring to the proper terminals. Modbus, when purchased, permits communication with Programmable Logic Controllers or Distributive Control Systems. Speed, speed setpoint, alarm and shutdown conditions, and other pertinent control information will be reported on request from a master unit. Page 5 of 6 Attachments 1- Configuration Sheet Links for Detailed Study 1- Installation and Operation Manual Peak® 150 Digital Control for Steam Turbines Page 6 of 6  Attachment-1 Woodward Peak 150 – Configuration Sheet Page 1 of 1 Manual 85565 Peak 150 Appendix. Program Mode Worksheets Introduction The program mode worksheets provide a step-by-step guide for programming the Peak® 150 control. You may copy or print out the worksheet for your use. To program the Peak 150 control, a hand-held programmer must be used (see Chapter 7, Programming for information on this unit and its use). WARNING—EXPLOSION HAZARD The Peak 150 control box should not be opened when a hazardous atmosphere is present. Wiring connections which could cause sparks are exposed inside the cabinet. WARNING—OVERSPEED PROTECTION Errors in configuration or programming of the Peak 150 control may create dangerous overspeed conditions. The turbine must be equipped with an overspeed device completely separate from the Peak 150 control or actuators attached to the Peak 150 control. The turbine must never be run when this device is not present or not operating correctly. WARNING—SAVE SET POINTS To prevent damage to the turbine resulting from improper control settings, make sure you save the set points before removing power. Failure to save the set points before removing power causes them to revert to the previously saved settings. Dangerous conditions such as turbine overspeed may result from operating the turbine with incorrect settings, possibly resulting in equipment damage and injury or death of personnel. CAUTION—DO NOT START TURBINE Do NOT attempt to operate the turbine until the Peak 150 control has been programmed. To do so could cause equipment damage; the turbine will start, come up to idle speed, trip and shutdown. Governor Serial Number __________________________________ Application _____________________________________ Configure Mode Program (The turbine must be shut down to enter this mode.) Enter the configure mode by pressing the "." key when the screen displays the "Woodward Governor Company" message. The "Woodward Governor Company" heading can be displayed by pressing the "ESC" (escape) key. Woodward 99 Peak 150 Manual 85565 Speed Configuration 50.00 Teeth Seen by MPU _______________ (number of teeth on the gear the magnetic speed pickup is looking at) 1.00 MPU Gear Ratio 1: _______________ (relationship to turbine shaft—the gear ratio is the result of dividing the MPU gear speed by the turbine shaft speed) 4418 MPU #1 Max Hz _______________ (maximum speed seen by the speed pickup) 4418 MPU #2 Max Hz _______________ (maximum speed seen by the speed pickup) 4417.93 Max Speed Level (Hz) _______________ (maximum speed level seen by the control) NOTE MPU #1 Max Hz, MPU #2 Max Hz, and Max Speed Level will normally all be the same setting. These speed levels must be above the overspeed test limit setting. 251.74 Minimum Speed Level (Hz) _______________ (minimum detectable speed level for the control—below this level the MPU would be detected as failed and an alarm will be issued. The MPU input signal must be at least 1.0 Vrms at the minimum speed level programmed. NOTE Pressing the "ESC" (escape) key will return the display to the heading, which would be Speed Configuration in this case. Using the right (or left) arrow key at the header will advance the display to the next header. Start Mode TRUE Manual Start Mode? _______________ (choose manual start mode vs. automatic start mode) Automatic Start Mode = (status indication only) FALSE (indication of auto start mode status-no config req'd) NOTE With manual start mode, governor speed control starts at minimum governor speed. With auto start mode, speed control starts at idle speed which is much lower than minimum governor speed. 100 Woodward Manual 85565 Peak 150 Actuator Configuration FALSE Use 20–160 mA Actuator? _______________ Use 4–20 mA Actuator = (status indication only) TRUE (indication of 4–20 mA driver status-no config req'd) NOTE Check that the proper jumpers are installed to provide the proper drive current. For a 0–200 mA drive current range, jumpers 4 and 10 should be installed. For a 0–20 mA drive current range, jumpers 3 and 9 should be installed. Operating Mode FALSE Manual Control Only? _______________ (all speed adjustments done with raise/lower contacts) TRUE Use Remote Speed Setting? _______________ (enables use of the remote 4–20 mA/1–5 V speed input if "Manual Control Only" is set to FALSE) NOTE Jumper must be selected for preferred input. FALSE Use High-Signal-Select? _______________ (enables high-signal-selection option between local speed set point and remote speed setting if "Manual Control Only" is set to FALSE and "Use Remote Speed Setting?" is set to TRUE) FALSE Use Modbus Analog Input? _______________ (enables using the remote speed setting through the Modbus link rather than with the analog 4–20 mA input if "Manual Control Only" is set to FALSE and "Use Remote Speed Setting?" is set to TRUE. Most importantly, you must have a unit capable of Modbus communications) Readouts 0.00 Speed Readout—4 mA Value = _______________ 5500.00 Speed Readout—20 mA Value = _______________ 1 Readout #2 Option? _______________ Readout #2 Options (enter option number) : 1. Actual Speed 2. Speed Set Point 3. Actuator Output 4. Remote Speed Set Point 5. Valve Ramp Value 6. Not Used NOTE Use the "+" and "–" keys to adjust the desired option number up or down respectively. Woodward 101 Peak 150 Manual 85565 500.00 Readout #2—4 mA Value = _______________ 10,000.00 Readout #2—20 mA Value = _______________ Relays 1 Configurable Relay #3 Option? _______________ (enter option number from list below) 1 Configurable Relay #4 Option? _______________ (enter option number from list below) Configurable Relay Options: 1. Alarm Condition (normally energized) 2. Trip Output (same as trip relay output) 3. Shutdown Condition (energizes on trip condition) 4. Remote Speed Control 5. Speed Control 6. Either/Any MPU Failed 7. Overspeed Trip 8. Overspeed Test 9. Remote Signal OK 10. Speed Switch or Hand Valve #1 11. Speed Switch or Hand Valve #2 NOTE Use the "+" and "–" keys to adjust the desired option number up or down respectively. FALSE Use Speed Switch? _______________ (enables setting and adjustment of speed switch levels in the service mode) FALSE Switch #2 Underspeed? _______________ (enables speed switch #2 to be used as an underspeed indication) FALSE Use Hand Valve(s)? _______________ (enables setting and adjustment of hand valve levels in the service mode) NOTE A combination of both a hand valve and a speed switch is not possible. If both "Use Hand Valve" and "Use Speed Switch" are set to TRUE, hand valves will be selected if option 10 or 11 is selected above in the Relay Options. FALSE Trip Relay Energizes for Trip? _______________ (trip relay to energize rather than de-energize on a trip condition) NOTE If the trip relay is programmed to energize for a shutdown, jumper 2 should be installed to properly display the units "Tripped" status on the front-panel LED. If the trip relay is programmed to de-energize for a shutdown, jumper 1 should be installed. 102 Woodward Manual 85565 Peak 150 FALSE Reset Clears Trip? _______________ (enables the trip output to be reset when a reset command is given without clearing the external trip input) NOTE When configuration is complete, press the "ESC" key until the display reads "Rebooting Control". Contact In #8 FALSE Configurable Contact #8 is Overspeed Test Enable? _______________ (True selects Contact #8 for Overspeed Test Enable, False selects Contact #8 for Fast Dynamics) Modbus Communication Port Configuration FALSE Use Modbus Communication Port? _______________ (enables Modbus communication port) 2 Hardware Configuration? _______________ (enter option number from list below) : Modbus Port Hardware Configuration Options: 1 = RS 232 2 = RS 422 3 = RS 485 2 Transmission Mode Configuration? _______________ (enter option number from list below) : Modbus Port Transmission Mode Configuration Options: 1 = ASCII 2 = RTU 1 Modbus Port Network Address Configuration? _______________ (enter number of address the control is on the network) Service Mode Program Enter the service mode by pressing the down arrow key when the screen displays the "Woodward Governor Company" message. Alarms MPU #1 Failed (status indication only) MPU #2 Failed (status indication only) Remote Input Failed (status indication only) Comm Link Failure (status indication only) Turbine Trip (status indication only) Woodward 103 Peak 150 Manual 85565 FALSE Use Trip as Common Alarm? _______________ (provides a common alarm condition when a trip condition exists) Trips Last Trip Code = (status indication only) (displays the cause of the last trip in code form—see below) External Trip (status indication only) Overspeed Trip (status indication only) Loss of Both MPUs (status indication only) Front Panel Trip (status indication only) Modbus Trip (status indication only) Last Trip Code (in Service mode) or Trip Cause Code on rpm display (flashed when a trip occurs): 1)External Trip to the Peak 150 control 2)Loss of both MPU inputs 3)Overspeed Trip indication 4)Front Panel Trip indication 5)Modbus Trip indication Speed Dynamics 0.95 Low Speed Gain _______*0.8________ 2.83 Low Speed Reset _______*5.0________ 8985.72 High Speed Switch Point (rpm) _______________ 0.93 High Speed Gain _______*0.8________ 2.56 High Speed Reset _______*5.0________ Hi Speed Selected (status indication only) Speed Values Actual Speed = (status indication only) Local Speed Set Point = (status indication only) Actual Speed Set Point = (status indication only) NOTE Normally the Local and Actual Speed Set Points will be the same. They will be different if remote speed setting is used as a high-signal- select and the remote setting is in control. Also, actual speed will differ from actual speed set point when droop is utilized. 104 Woodward Manual 85565 Peak 150 Remote Spd Setting = (status indication only) (displays Actual Remote Set Point) 20.38 Start Ramp Rate (rpm/sec) _______________ (rate of change for startup control operation) 4.78 Set Point Slow Rate (rpm/sec) _______________ (rate of change for normal manual control operation) 2.95 Delay for Fast Rate (sec) _______________ (manual mode delay time before fast rate of change starts) 14.61 Set Point Fast Rate (rpm/sec) _______________ (manual mode fast rate of set point change) 751.10 Min Governor Speed (rpm) _______________ (normal governor operation lower limit) 4725.81 Max Governor Speed (rpm) _______________ (normal governor operation upper limit) 4950.00 Overspeed Level (rpm) _______________ (governor only—not to be used as ultimate trip protection) 5094.47 External Ospd Level (rpm) _______________ (lower limit of external overspeed trip device) 5302.81 Overspeed Test Limit _______________ (absolute maximum speed allowed for overspeed test) NOTE The overspeed test limit cannot exceed the Max Hz settings from page 100. 0.08 Droop (%) *0.0 _______________ (droop percentage—typically set to 0.0) FALSE Use Set Point Set-Back _______________ (instantly resets the speed set point to the actual running speed when the raise or lower pushbuttons are released) Remote Setting (displayed only if Remote is configured) Actual Remote Set Point = (status indication only) Remote Set Input = (status indication only) NOTE Normally the "Actual Remote Set Point" and "Remote Set Input" will be the same. They will be different if the analog (remote) input is being rate limited or the analog input is failed. 5.00 Remote-Not-Matched Rate _______________ (speed set point rate used before the local and remote settings are matched) Woodward 105 Peak 150 Manual 85565 100.00 Remote Rate—Max (rpm/sec) _______________ (maximum allowed rate of change to the speed set point allowed—used to rate limit the analog input's effect on speed) Modbus Remote Used = (status indication only) Failed MPU Override 268.33 Auto-Ovrd-Off Speed (Hz) = _______________ (speed that failed MPU override is turned off—MPU must be providing at least 1.0 Vrms) TRUE Use MPU Override Timer? _______________ (the timer limits the time after a start command for speed to be detected— if set properly, this is a protection against overspeed if both MPUs are bad) 399.09 Max Starting Time (sec) = _______________ (if using timer, this sets the maximum starting time allowed after a start is initiated to sense the "Auto-Ovrd-Off Speed" set above) FALSE Use Slow Rolldown Ovrd? _______________ (turns on the failed MPU override if the speed is being slowly reduced by closing the trip and throttle or stop valve—this override is turned on after the speed drops below a low speed setting for delay time. Using this option allows the operator to resume operation at the last set point on the next startup rather than at minimum set point) 310.91 Auto-Ovrd-On Speed (Hz) = _______________ (for use with the slow rolldown ovrd option—when speed drops below this low speed setting for the delay time, the override is turned on) 5.00 Auto-Ovrd-On Delay (sec) = _______________ (for use with the slow rolldown ovrd option—the delay time associated with turning on the override. If the speed drops below the "minimum speed level" setting before the time expires, the unit will trip on loss of MPU signals and reset the speed set point to minimum) Ovrd ON Status = (status indication only) Idle/Min Gov Ramp (displayed only if Auto Start is configured) Idle Speed (rpm) _______________ (absolute lowest speed set point - where speed control initially starts if using automatic start mode) Use Idle/Min Gov Ramp? _______________ (allows the operator to close the idle/min gov contact to automatically ramp from idle speed to minimum governor speed) Minimum Governor Speed (rpm) _______________ (set point that the idle/minimum governor ramp heads toward when the function is enabled) Idle/Min Gov Rate (rpm/sec) _______________ (rate the set point changes at when ramping to minimum governor or back to idle) 106 Woodward Manual 85565 Peak 150 Use Ramp to Idle Function? _______________ (allows the operator to open the idle/min governor contact to automatically ramp the speed set point to idle speed - this function is disabled if "Start=Ramp to Min Gov" is set to TRUE) Start = Ramp to Min Gov? _______________ (allows using the front panel "Start" key in place of the idle/min governor contact input - pressing start after the unit is running would start or resume ramping to minimum governor speed. When this function is used, the "Ramp to Idle Function" is disabled) Ramping to Min = (status indication only) Ramping to Idle = (status indication only) Critical Speed Band (displayed only if Auto Start is configured) Use Critical Band? _______________ Critical Speed Min (rpm) = _______________ (critical speed band lower limit) Critical Speed Max (rpm) = _______________ (critical speed band upper limit) Critical Band Rate (rpm/sec) = _______________ In Critical Band = (status indication only) SPD SW/Hand VLV (displayed only if configured) Relay #1 On (rpm or %) _______________ (the speed level or valve position level this relay turns on or energizes at. A configurable relay must be using option 10, which is speed switch or hand valve #1, and "Use Speed Switch" or "Use Hand Valve" must be configured to true to use this function) Relay #1 Off (rpm or %) _______________ (the speed level or valve position level this relay turns off or de-energizes at) Relay #2 On (rpm or %) _______________ (the speed level or valve position level this relay turns on or energizes at. A configurable relay must be using option 11, which is speed switch or hand valve #2, and "Use Speed Switch" or "Use Hand Valve" must be configured to true to use this function) Relay #2 Off (rpm or %) _______________ (the speed level or valve position level this relay turns off or de-energizes at) Underspeed Level (rpm) _______________ (the speed level where an underspeed condition will occur on decreasing speed, overridden until Minimum Governor Speed Is Achieved.) Woodward 107 Peak 150 Manual 85565 Valve Output Valve Position (%) = (status indication only) Valve - Offset Adjust _______*0.0________ Valve - Gain Adjust _______*1.0________ Valve Ramp Position = (status indication only) Manually Raise Ramp ? ______*false_______ (no configuration req'd - this function is provided as a troubleshooting tool) Manually Lower Ramp ? ______*false_______ (no configuration req'd - this function is provided as a troubleshooting tool) 5.00 Ramp Rate (%/sec) = _______________ (this rate determines how fast the governor valve will open during a turbine start) Dither Adjust _______*0.0________ (normally set to 0.0 - if dither is necessary, this adjustment can be set to a higher value) Stroke Valve Output? ______*false_______ (this function can only be performed when the turbine is shutdown) 100.00 Stroke Position (%) _______*0.0________ (this can be adjusted between 0% and 100% for stroking the valve as long as min/max switch is set to false) Min/Max Switch ______*false_______ (shortcut used in stroking the valve - by adjusting between false to true the output strokes between 0 to 100%) Readout Adjustments -7.81 Readout #1 (Speed Readout) - Offset Adjust _______*0.0________ Readout #1 (Speed Readout) - Gain Adjust _______*1.0________ Readout #2 (Config Readout) - Offset Adjust _______*0.0________ Readout #2 (Config Readout) - Gain Adjust _______*1.0________ Readout #2 Value (indication only) (value of the configured parameter to be output by readout #2) Modbus Communication Port Adjustments Modbus Port Hardware Configuration? _______________ (enter option number from list below): Modbus Post Hardware Configuration Options: 1 = RS 232 2 = RS 422 3 = RS 485 108 Woodward Manual 85565 Peak 150 Modbus Port Baud Rate Configuration? _______________ (enter option number from list below): Modbus Port Baud Rate Configuration Options: 1 = 1200 Baud 2 = 1800 Baud 3 = 2400 Baud 4 = 4800 Baud 5 = 9600 Baud 6 = 19200 Baud Modbus Port Stop Bit Configuration? _______________ (enter option number from list below): Modbus Port Stop Bit Configuration Options: 1 = 1 Stop Bit 2 = 1.5 Stop Bits 3 = 2 Stop Bits Modbus Port Parity Configuration? _______________ (enter option number from list below): Modbus Port Parity Configuration Options: 1 = Off Parity 2 = Odd Parity 3 = Even Parity Link Error = (status indication only) Exception Error = (status indication only) Error Number = (status indication only) Error Percent = (status indication only) I/O Check MPU #1 = (rpm status indication only) MPU #2 = (rpm status indication only) Analog Input = (% status indication only) DI #1 = (Lower Speed – True or False status indication only) DI #2 = (Raise Speed – True or False status indication only) DI #3 = (External Trip – True or False status indication only) DI #4 = (Start – True or False status indication only) DI #5 = (Reset – True or False status indication only) DI #6 = (Idle/Min Gov – True or False status indication only) DI #7 = (Remote Speed Enable – True or False status indication only) Woodward 109 Peak 150 Manual 85565 DI #8 = (Ospd Test/Select Hi Dyn – True or False status indication only) Trip P/B = (OCP Trip – True or False status indication only) Ospd Test P/B = (OCP Ospd Test – True or False status indication only) Raise P/B = (OCP Raise Speed – True or False status indication only) Lower P/B = (OCP Lower Speed – True or False status indication only) Start P/B = (OCP Start – True or False status indication only) Reset P/B = (OCP Reset – True or False status indication only) Tripped LED = (True or False status indication only) MPU #1 OK LED = (True or False status indication only) MPU #2 OK LED = (True or False status indication only) Ospd Enabled LED = (True or False status indication only) RMT SPD LED = (True or False status indication only) Trip RELAY ON = (True or False status indication only) Alarm RELAY ON = (True or False status indication only) Conf Rly #1 ON = (True or False status indication only) Conf Rly #2 ON = (True or False status indication only) 110 Woodward Anti-Surge Controllers - Centrifugal Compressors CCC Series 3 Plus Controller What is a Surge? Surge is defined as the operating point at which centrifugal compressor peak head capability and minimum flow limits are reached. Actually, the working principle of a centrifugal compressor is increasing the kinetic energy of the fluid with a rotating impeller. The fluid is then slowed down in a volume called the plenum, where the kinetic energy is converted into potential energy in form of a pressure-rise. When the plenum pressure behind the compressor is higher than the compressor outlet pressure, the fluid tends to reverse or even flow back in the compressor. As a consequence, the plenum pressure will decrease, inlet pressure will increase and the flow reverses again. This phenomenon, called surge, repeats and occurs in cycles with frequencies varying from 1 to 2 Hz. So, the compressor loses the ability to maintain the peak head when surge occurs and the entire system becomes unstable. A collection of surge points during varying compressor speed or varying inlet gas angle is fitted as surge line. In normal conditions, the compressor operates in the right side of the surge line. However, during startup/emergency shutdown, the operating point will move towards the surge line because flow is reduced. If conditions are such that the operating point approaches the surge line, flow recirculation occurs in the impeller and diffuser (Figure 1). The flow separation will eventually cause a decrease in the discharge pressure, and flow from suction to discharge will resume. Surging can cause the compressor to overheat to the point at which the maximum allowable temperature of the unit is exceeded. Also, surging can cause damage to the thrust bearing Page 1 of 6 due to the rotor shifting back and forth from the active to the inactive side. This is defined as the surge cycle of the compressor. Anti-Surge Control Systems These systems detect when a process compression stage is approaching to surge and subsequently take action to reverse the movement of the operating point towards the surge line (SL). This decreases the plenum pressure and increases the flow through the compressor, resulting in stable working conditions. It is normally achieved by opening a control valve in a recycle line (Anti-Surge Control Valve or ASCV), returning the discharge gas to the inlet of the compressor via a suction cooler. The resulting increase in compressor inlet volume flow moves the operating point away from surge. Figure 2: Surge Protection Definitions Due to inaccuracies in measurements and response times of transmitters and valves, Anti-surge control achieves a surge control line (SCL) parallel to the surge limit line. The control line is offset to the right of the surge line by a margin; typically equal to 3- 10% of inlet volume flow at surge (Figure 2). However, a lower margin is also desirable because higher efficiency could be obtained by closing the recycle valve. In real operation, compressor performance curves in the coordinate system are unique for constant given suction conditions. This means that the variation of inlet conditions leads to changing compressor performance curves. On the other hand, since inlet temperature decreases, inlet molecular weight increases or inlet pressure increases, the differential pressure across measuring device would go up for the same inlet capacity. So for the purposes of control, new coordinate system is used which must be invariant (or independent) to changes in inlet conditions. Therefore, the effects of inlet temperature, gas molecular weight and compressibility factor are not required to be considered in the controlling Figure 3: Compressor Map system. In this regard, several invariant coordinates are obtained by compressor manufacturer. They use dimensional analysis for the generation of these invariant Page 2 of 6 systems (or compressor map). The two most important systems are: 1) Compressor polytropic head (or differential pressure) versus square of flow rate in suction and 2) Pressure ratio versus square of flow rate in suction. Flow through the compressor suction is equivalent to the pressure drop in orifice or venturi installed at the inlet or outlet of compressor. Thus, pressure loss in orifice or venturi can be calibrated as a function of compressor flow rate. A compressor map is illustrated by superimposing both performance and system resistance curves independent of rotational speed (Figure 3). For compressors with inlet guide vanes, compressor map is represented by a new family of curves that do not depend on suction conditions either. This additional coordinate could be a function of either guide vane position or equivalent rotational speed. Anti-Surge Controller System And Algorithms Proportional–integral (PI) and proportional–integral–derivative (PID) are two major control algorithms which are used to control imperfectly known compression systems. The basic procedure of these algorithms is that the controller output should be a function of the difference (Error, e) between two values which should be controlled (process variable, PV) and its set point (SP) (Figure 4). When operating in the stable region at the right-hand side of the SP-line, where the error, e, is positive, the controller output is forced to be zero and integrators should be reset to avoid wind- up. As the flow decreases due to a disturbance, PV decreases as well and — at a certain point — where PV< SP, the error, e, becomes negative. Here, the controller comes into action opening the anti-surge valve. This action pushes the PV back to the stable region at the right-hand side of the Figure 4: Compressor Controller Schematic SP-line. Moreover, small disturbances should not lead to big reactions. But a fast and resolute opening of the valve is required when the control line is exceeded in the direction of the surge limit. Therefore, the controller has a nonlinear gain behavior when the controller deviation (PV-SP) is negative. Earlier matter about nonlinear gain controller leads to considering derivation term in logic control of system. Actually, effect of the derivative (D-action) term is that it often allows the control response to be accelerated without increasing the risk of instability, because it is a measure how fast the system is responding and action will tend to counter the oscillatory action. However, it will also make the system more sensitive to signal noise. Thus, the simpler PI algorithm is sometimes more useful than full PID control. But it (PI) is limited in speed of its response and is unable to take the machine out of surge in the event that the operating point crosses the surge line. Page 3 of 6 In other words, the D-action should be incorporated by changing the set point due to a change in flow (dF/dt). When the flow decreases rapidly (dF/dt