Turbine automatic speed control system Woodward
«Komdiagnostikа» LLC has realized projects on design, supply and modernization of turbine and compressor units control and monitoring systems at such sites as «Gazprom dobycha Astrakhan», «Gazprom neftehim Salavat», OJSC «Dorogobuzh», OJSC "Mineralnyje udobreniya" (Perm).
The system is constructed on the basis of Woodward hardware and software monitoring devices.
The system satisfies up-to-date requirements and provides the following advantages:
- the system has modular structure and is "open" for the Customer so that there is a possibility for modernization during operation;
- For high efficiency of the unit operation the system secures:
a) precise process regulation;
b) precise regulation of the main parameters;
c) monitoring, diagnostics and protection;
- the system has high reliability because of reduction of hardware of different manufacturers;
- control algorithm designed during long years of practice;
- serial interface of the turbine current data acquisition distributed system;
- the system is programmed to correspond to the Customer needs;
- reduced original cost of control and operation hardware.
Main tasks, carried out by automatic control and monitoring system, are growth of economic efficiency, cost effectiveness, reliability of technologic process. The systems makes it easier to control technologic process, allows widening the range of the possible operation modes due to precise and reliable performance of restrictions of process parameters. Integration of system reduces costs on repair, setting and maintenance of turbo-compressor units control and monitoring systems, on repair of main equipment and its downtime due to the reduction of possible emergency situations.
Design, supply of equipment and integration of control system includes:
- replacement of hydraulic and mechanical gas and steam turbines regulatory systems on the systems, realized on the basis of microprocessor software and hardware complex which are connected to control valves servo motors through electro-hydraulic converters;
- replacement of anti-surge compressor regulators on program regulators which are loaded into controllers of the same microprocessor software and hardware complex;
- supply of anti-surge valves with pneumatic actuators;
- supply of turbine rotor speed sensors, steam pressure sensors, pressure, temperature and gas flow sensors, regulatory valves servo motor position sensors and of other parameters in the volume necessary for operation of the newly installed regulators.
The system provides a possibility, on operator's command, of machine operation in automatic or manual modes. Automatic mode is the basic mode, manual is an auxiliary mode. The system can be controlled from DCS working stations or from local control box. Control from DCS working stations or from local control boxes (e.g. during start-up) is the main variant.
The system has a decent redundancy level on main and auxiliary elements of hardware complex. The system secures optimal for production process loads during machine operation, enhances reliability and availability of equipment, increases overhaul life.
Main functions of the system:
1. Regulation and control
- parameters of turbine operation: control of rotation speed in automatic or manual modes;
2. Machine protection:
- from exceeding of allowable rotation speed ;
3. Выполнение последовательности пусковых операций:
3.1. Depending on the mode:
- in automatic mode;
- in manual mode;
3.2. Depending on the turbine thermal condition:
- from «hot» condition;
- from «cold» condition;
3.3. Depending on the place of control:
- From DCS working stations;
- from local control box;
4. Execution of shutdown process sequence:
4.3. Depending on the place of control:
- from ESD to DCS;
- from DCS working stations;
- from local control box;
5. Diagnostics and monitoring of hardware complex:
- setting and monitoring of controllers;
- setting and monitoring of actuator;
- controllers technical condition monitoring;
- speed measuring channels technical condition diagnostics;
6. Integration of systems in DCS:
- communication with DCS controllers through physical and digital channels which provide execution of all the above mentioned functions from central control rooms.
Application of the comprehensive turbine and compressor units control system allows realizing the function of load distribution between compressors during parallel or consecutive operation to the network.
Sites which operate turbine units with application of comprehensive equipment gain competitive advantage not only due to reduction of energy consumption, increase of quality of production but also due to reduction of emergency shutdowns because of failure or malfunction of control system as well as due to expansion of information field of the unit technical condition which, in combination with the modern diagnostics system, allows optimizing costs not only on spare parts and repair but also on maintenance service.