Compressor anti-surge control system Woodward
Compressor surge processes, which arise in case of low gas flow insufficient for support of existing pressure difference, are controlled by measuring the pressure difference with differential manometers, connected with DCS, and by generation of signals for opening of anti-surge recirculation valves automatically or manually from DCS operator's control panel. At transient state of compressor operation efficiency factor maximum range, operation is impossible without recirculation because of operator's low speed of response to the beginning of surge. For the same reason it is impossible to use any preemptive influence on various parameters of compressor operation.
Surge is a dangerous regime of dynamic compressor operation which begins in case of low gas flow insufficient for support of existing pressure difference. Specialists of Komdiagnostika offer a reliable algorithm of anti-surge control on the basis of controller Micronet Plus of Woodward Company.
Time of transition from normal operation to surge condition is about 40 milliseconds. Such regime signifies destabilization and stall which initially lead to gas backflow. Controller Micronet Plus corresponds to all these strict operation conditions, its response time to the beginning of surge is no more than 40 milliseconds (full response time).
Controller Micronet Plus can be configured for working with various types of turbines and compressors, the set goal is flexible control of rotation speed and/or gas flow during discharge of compressor as well as anti-surge control and protection. To support control flexibility, all inputs and outputs are configured by the user. The user can add input/output modules to increase the redundancy level and/or to enlarge the possibilities of input/output quantity.
Control system MicroNet Plus can work in redundancy configuration Master/Slave to provide a higher reliability level. Synchronized memory secures that both processors use one and the same on-line information in any speed group. If Master processor fails, all system control, including control of inputs/outputs, transfers to redundant CPU module in less than 1 millisecond with no harm to operation of the input drive. Once the malfunction of Master processor is eliminated, the system can continue working with redundant CPU or control functions may be passed back to the main Master processor. Indication of transition to one of the two control regimes is done through communication links.