Automated control system of 4 MW turbine expander disposal unit
“SAU-UTDU4000”
Customer:
Open Joint-Stock Company “TURBOGAS”
Implementation:
Gas-distributing station (GDS) Severodonetsk, Ukraine, 2008
General information:
“SAU-UTDU 4000” is designed to automize operation and emergency protection of turbine expander disposal unit (TEDU) “UTDU4000”, producer Open Joint-Stock Company “TURBOGAS”. This unit is assigned to decrease main gas pressure down to the pressure available for consumers. At once disposal electrical power is obtained by means of generator connected to TEDU shaft and transferred to electric mains.
Operation: Gas from GDS enters heat exchanger, then preheated gas gets to shutoff-measuring unit (consisting of shut-off and measuring valves) and through oil-cooler system is delivered to GDS low pressure header and then to consumers. Turbine expander rotor by reduction gear is attached to generator rotor that is connected to external electric mains.
Functions:
- gas pressure maintenance at TEDU output according to GDS or operator command;
- TEDU rotor speed regulation (achieving rated speed frequency, generator synchronization with electric main, no-load discharge);
- limited regulation of generator capacity;
- TEDU emergency protection at all operation modes;
- TEDU operation ability check;
- TEDU start;
- generator loading;
- TEDU no-load discharge;
- TEDU standard stop;
- TEDU emergency stop;
- automatic (according to technological algorithm) and remote (at operator command) auxiliary equipment control;
- history data of technological process and operator activities;
- organization of advanced operator interface including dynamic mimic schemes, parameter tables, diagrams and histograms;
- automatic reports generating;
- automatic diagnostics of soft- and hardware, communication channels, measuring channels, control circuits and device positions
- supply control.
Technical solutions:
“SAU-UTDU 4000” is GE Fanuc Automation PLC RX3i - based. Soft-, hardware reliability is provided by:
- reserving of TEDU rotor rotations measuring channels;
- reserving of supply units;
- reserving of operator interface;
- reserving of digital communication channels with ACS GDS by transferring critical commands through physical circuits;
- embedded self-diagnostic aids and automated control of input-output analogue and discrete circuits integrity.
Operation safety is provided by emergency stop unit (ESU). Unit is functionally independent from control system and has independent protection channel at TEDU limit rotor speed overrun. ESU provides PLC operation control and TEDU safe stop in case of fault.
“SAU-UTDU4000” hardware provides signals reception from:
- pulse transmitters (0…20) kHz – 2 ;
- resistive temperature transducers – 40;
- transmitters with normalized signal (4-20) mA, (-10...+10) V, (0…+10) V – 48;
- discrete =24 V – 120
“SAU-UTDU4000” hardware provides control signals output:
- normalized current signals (4-20) mA, (-10...+10) V – 4;
- discrete – 96
Value of main reduced error of data-measuring and control channels (regardless of transducers and connection lines errors):
- from pulse transmitters (0…20) kHz – 0,15%;
- from transmitters with normalized signal (4-20) mA, (-10...+10) V, (0…+10) V – 0,1%;
- from resistive temperature transducers – 0,4%;
- normalized current control signals (4-20) mA, (-10...+10) V – 0,1%.
Uninterruptible supply is provided by UPS that let “SAU-UTDU4000” operate independently for 15 minutes (with all transducers connected). Electric energy demand of ac network 220V 50 Hz is not more than 1 kW
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