CCS developed a set of turbo machinery control applications for Gas Turbine Control (GTC), Steam Turbine Control (STC), Surge Prevention Control (SPC) and Station Control (SC).
We only utilize leading third-party off-the-shelf hardware and software products to implement our patented algorithms. All turbo machinery control applications are developed according to specific rules and requirements, which ensure the compatibility of applications with the vendor software package:
• Implementation of critical turbo machinery controls on any IEC61131 compliant hardware platform offering multi-level availability classes like SIL2 and SIL3. You may even choose your hardware platform, thereby reducing the need for additional spare parts and training expenses.
• Special tuning and maintenance screens for testing and validating your turbo machinery specific machinery parameters such as electronic overspeed testing and compressor surge line validation.
• All our turbo machinery control applications are configured, operated and maintained via a selected HMI software package vendor. The control applications use a limited, pre-defined set of configuration parameters.
Our turbo machinery control applications can also be integrated into the existing train control system. This integration results in an increased train control system availability, reliability and reduced system cost as dedicated turbo machinery control processors, racks or power supplies are superfluous.
Gas Turbine Controller
The Gas Turbine Controller (GTC) designed and developed by Continuous Control Solutions provides a versatile and cost-effective way to control an industrial or aero-derivative gas turbine.
In addition to regulating speed or power, it also protects against excessive temperatures, speeds or pressures and sequences the fuel flow during startups and shutdowns. The GTC is offered for single and/or multi-shaft turbines driving variable-speed loads or synchronous generators. Their redundant inputs, contingency strategies and redundancy capabilities characterize an innovative, more cost-effective approach to fault tolerance than was previously available for such machines.
Limiting Control
Limiting loops are provided for all shaft speeds, and allowing user to define independent high speed alarm and electronic overspeed trip speeds for each shaft. In addition, the overspeed test allows you to raise the turbine’s speed until its primary trip is triggered, and captures that maximum speed for later display. Acceleration and deceleration can be limited not only by scheduling the fuel flow range, but also by setting fuel flow and NGT rate-ofchange limits. The GTC includes the following control loops: • High Pressure rotor speed (NHP) Control • High Pressure rotor speed (NHP) Limiting Control • Low Pressure rotor speed (NLP) Limiting Control • Turbine’s Axial Compressor Discharge Pressure (CDP) Control • Power Turbine Speed (NPT) Control • Exhaust Gas Temperature (EGT) Limiting Control • Maximum Fuel / Valve Schedule (Acceleration control) • Minimum Fuel / Valve Schedule (Deceleration control) Additional multi purpose control loops can be configured using CCS’ PID multi-loop module (10 loops maximum), redundant configurations are also available.
Upgrading many gas turbines’ control systems often comprises upgrading fuel systems valves, pumps and related equipment. Sometimes fuel systems are also added in fuel conversion projects to add dual fuel capability on a turbine previously operating on a single fuel. CCS provides you with complete fuel system design compatible with the control system and turnkey installation. The GTC and its fuel system are available for new and retrofit applications and can be configured to control your gas turbine in accordance with turbine manufacturer provisions and is usually integrated into the train control system. It is fully compatible with our Surge Prevention Controller (SPC), Station Controller (SC) and our Optimization Package. This integration results in increased train control system availability and reliability as well as in reduced system cost, because dedicated speed control processor, rack and power supply are not required. Our GTC application helps you to effectively protect and control your gas turbine during start-up conditions as well as during (ab)normal operation with minimal operator intervention.
Steam Turbine Controller
The Steam Turbine Controller (STC) designed and developed by CCS enables fully automated speed control during normal operation as well as startup/shutdown speed control including critical speed avoidance.
It provides for a versatile and economical way to regulate your steam turbine’s speed or power, protects the turbine against overspeed damage and automatically sequences startups and shutdowns. CCS offers you turbine speed control upgrades of both mechanical and early electronic control systems for a variety of control platforms. Our custom engineered retrofit package will deliver you a full complement of digital controls and mechanical-hydraulic modifications needed to modernize your turbine governor.
The STC can also be programmed to control and safeguard the driver and the driven equipment. Improper start-up is perhaps the greatest threat to a turbine’s longevity. To avoid damage and minimize wear, it must be warmed up at the appropriate idle speed. If various external conditions (proper lube oil pressure, for example) are not met, the procedure must be aborted. Speeds at which vibration or other damage is likely, must be prevented.
Failure to consistently follow these procedures can cause unnecessary wear or damage. To minimize these risks, the Steam Turbine Controller provides automatic start-up sequencing that includes precise control of the idle speed, configurable acceleration ramps that exclude critical speed ranges and discrete start permissive inputs in accordance with the turbine manufacturer specifications.
Features: • Speed Control • Load Control • Load Rejection Protection • Flow Characterization • Pre-warming • Protective System Testing • Over-speed Protection • Valve Testing Additional multi purpose control loops can be configured using CCS’ PID multi-loop module (10 loops maximum), redundant configurations are available.
STC is fully configurable to any industrial steam turbine and is typically integrated into the train control system. This integration results in improved train control system availability and reliability as well as in reduced system cost, because dedicated speed control processor, rack and power supply are not required.
Our STC is fully compatible with our Surge Prevention Controller (SPC), Station Controller (SC) and our Optimization Package.
Our STC application helps you to effectively protect and control your steam turbine during start-up conditions as well as during (ab)normal operation with minimal operator intervention.
Surge Prevention Controller
The Surge Prevention Controller (SPC) designed and developed by Continuous Control Solutions, protects your centrifugal or axial compressor from experiencing surges efficiently and reliably.
CCS’ method of accurately defining the surge line over a wide range of changing conditions allows you to set the control safety line for optimum surge protection without unnecessary recycling or blow-off. The controller provides fully-integrated multi-loop, multiple-body compressor surge control on a hardware independent platform.
Benefits • Patented proximity to surge calculation: Compressor’s operational distance to surge is determined based on two independent surge proximity calculations: (1) compression ratio (Rc) and (2) compressor flow (dP). This technique allows better calculation accuracy especially for multi stage and/or sideload (sidestream) compressors.
• PID loops: The SPC offers two PID loops for your compressor’s surge control. It uses the first PID loop module to control the operating point of the compressor below pressure ratio at surge conditions by a safety margin based on compression ratio (Rc). The second PID loop controls the operating point above the surge flow by a safety margin based on flow (dP). • Rate-Of-Change (ROC) algorithms: With CCS developed ROC calculation on field signals as well as on surge prevention calculations, the surge of a compressor will be prevented by rapidly opening the recycle valve and moving the control line to a pre-selected position. • User friendly compressor surge line validation: Simplified controller calibration and compressor surge line validation by standard HMI screens and no manual calculations. Once a surge point is recorded the controller allows automatic configuration reducing the risk of manual configuration errors. • Compressor surge counters: Independent surge counters are available, allowing you to configure a shutdown command in case prolonged surging is seen caused by antisurge valve malfunctioning for instance. • Derivative algorithms: During rapid decreases in flow near the control line, the derivative control algorithm opens your antisurge valve before the operating point reaches the control line. • Variable gains: If the operating point of the compressor rapidly decreases to flow values beyond the allowable safety margin, the traditional PI control is enhanced by the variable proportional gain to facilitate rapid opening of your antisurge valve.
• Override functions: Automatically transfer to automatic mode to protect your compressor from damages due to operator error.
• Limiting control: SPC includes an additional multipurpose PID control loop to limit for instance your compressor’s discharge or suction pressure by increasing the recycle rate. • Patented fallback algorithms: Even when compressor flow indication is no longer available, continued automatic operation of the controller is warranted. Any type of failure of field transmitters does not interrupt continued, safe operation of your turbo machinery. • Automatic start-up and shutdown modes: Additional algorithms to provide for smooth start-up and shutdown modes of your compressor in accordance with the compressor manufacturer's specifications and in compliance with your process requirements. • Optional anti-choke control: SPC can be configured for compressor anti-choke (stone-wall) protection. • Feed forwarding: Integrated with other SPC’s; preventing loop interactions and process destabilization. • Compatibility: SPC is fully compatible with our Station Controller (SC), Gas Turbine Controller (GTC), Turbine Speed Controller (STC) and our Optimization Package.
Our SPC application helps you to effectively protect your turbo compressor from surge during start-up conditions as well as during (ab)normal operation with minimal recycle or blow-off. Минимизация зоны регулирования приводит к снижению рециркуляции и повышает экономичность работы компрессора на 4-6%.
Station Controller and Cold Recycle Controller
The Station Controller (SC), designed and developed by Continuous Control Solutions, performs load-sharing or load-balancing of your multiple compressor trains, controls your single train performance and provides control for an optional cold recycle valve arrangement.
The SC is capable of controlling your main station’s parameter and/or individual train control parameter by using multiple PID algorithms.
Supported popular control parameters are: • Station suction/discharge pressure or compressor train suction/discharge pressure. • Station or compressor train’s compression ratio. • Station or compressor train’s flow rate.
The controller provides fully-integrated multi-loop, compressor load-balancing or performance control on a hardware independent platform.
Load-sharing or load-balancing (LB) between your units working in parallel and/or series operation mode is performed using a predefined optimization target; compressor efficiency, minimum station fuel gas consumption or speed for instance are common selections using our basic algorithms. Which algorithm is used to achieve your selected target depends on your unit’s condition: • Surge Prevention Control (SPC) algorithm: When one of your units approaches surge line while others operate in normal condition, the SC directs control to the SPC algorithm to unload the others and forcing more load to your unit close to surge. • Load-balancing (LB): When all of your units are close to the surge line, the LB algorithm smoothly evens their speeds (rpm) or compression ratio (Rc), while maintaining your main controlled process parameter. • Optimizing algorithm: When all of your units operate in normal condition, e.g. far away from the surge line, the optimization algorithm takes over the control action and determines load-sharing between working units based on a predefined optimization target specified by you (e.g. fuel gas reduction).
The SC has up to two main process variables available for control; for instance (1) primary – station pressure and (2) alternative – station flow. In addition, the SC offers protection by utilizing two limiting variables. One of them is usually the station temperature while the other can be assigned during project design stage. Bumpless transfer between primary and alternative control and limit control mode is warranted during normal operation.
Other vital functions offered include: • Automatic sequencing of compressor start-up and shut-down. • Integrated with Surge Prevention Controllers (SPC) preventing loop interactions and process destabilization. • Bumpless transfer between manual and automatic operating modes. • Input fault detection and fall back strategies that will keep your compressor on-line in the event of a transmitter failure. • Feed forward control: Our SC regulates the pressure or flow in a header by directly manipulating fuel control valves (or inlet throttle valve position) of each parallel/series operating unit to minimize fuel consumption while maintaining its primary process control parameter. • Compatibility: Our SC is fully compatible with our Surge Prevention Controller (SPC), Gas Turbine Controller (GTC), Turbine Speed Controller (STC) and our Optimization Package.
In case your station or plant is equipped with a cold recycle line, the Cold Recycle Controller (CRC) manipulates the cold recycle control valve. In case the recycling takes place on any of the units, the CRC opens the cold recycle valve allowing for the alternative recycling path for the gas. Subsequently this will allow closure of your unit’s antisurge valve. In normal operating conditions all unit antisurge valves and the CRC valve are closed. In case of rapid and high amplitude disturbances the SPC controllers react first by opening the unit’s antisurge valve to the position determined by the magnitude of the calculated recycle flow. Then the CRC gradually opens your cold recycle valve to increase the flow rate through the cold recycle line, which allows for closing of the units’ antisurge valves.
Our SC application helps you to effectively control the performance of your turbo compressor(s) during start-up conditions as well as during (ab)normal operation with minimal operator intervention.
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