This presentation will probably involve audience discussion, which will create action items. Use PowerPoint to keep track of these action items during your presentation • In Slide Show, click on the right mouse button • Select “Meeting Minder” • Select the “Action Items” tab • Type in action items as they come up • Click OK to dismiss this box • This will automatically create an Action Item slide at the end of your presentation with your points entered. Power Gen’sPt.Lisas Power Station Control System Retrofit
The Power Generation Company of Trinidad and Tobago was formed on 24 December 1994. This date saw the separation of the power generation function from the transmission and distribution functions which were retained by the predecessor company T&TEC. The ownership of Power Gen is as follows: T&TEC 51% Mirant Corporation 39% bp Business Dev 10 % The Mirant Corporation has the day-to-day responsibility of managing the company.
The company owns three generating stations on the twin-island republic of Trinidad & Tobago: Port-of-Spain B Station 320 MW Pt.Lisas Power Station 630 MW Penal Power Station 226 MW Total installed capacity 1176 MW A Power Purchase Agreement presently sets the legal framework for capacity availability and delivery of generated power to T&TEC’s T&D facilities.
Control Systems Historical Overview • Historically, our machines were operated for their lifetime with whatever control systems they were built with. • POS B steam & Penal combine cycle units still have their original hybrid controls. • DCS, PLC technology can emulate pneumatic,hydraulic,relay controls.
Project Justification • Need for the retrofit • excessive machine trips ( 100 trips in ‘95 at PTLS )
Project Justification (cont’d) • Magnetic core memory : US$15,00.00 • Lead time 4-6 mths • Analog input module:US$14,000.00 • Lead time 3-5 mths • ABB & Westinghouse machines’ Magnetic • core memories were not tolerant • of high ambient temperatures. • Stuck mercury wetted contact in 4AP analog input module • throws off 50mV,5V Ref readings resulting is controller trip. • Long Mean Time To Repair(MTTR) meant • long forced outages • Many failure points • Complicated system configuration
Justification ( cont’d) • PTLS 11 : an 85 MW machine tripped • typically once per day…. • Control system obsolescence • High cost of control system spares • and maintenance. • Steel Mill loading problem. • Contractual obligations under the new. • PPA for automatic accumulated clock • cycle error.
RFQ issued while T&TEC • RFQ and Technical Specifications written jointly by T&TEC Eng Services and Pt.Lisas Power Station personnel, while we were one company, circa mid 1994.
RFQ reissued under Powergen • Initial RFQ was issued before the formation of Power Gen and bids received from retrofit companies including the OEMs. • After the formation of PowerGen, legally we had to re-issue the RFQ since the original offerings were made T&TEC.
Schedule • Initial schedule called for a 3 year engineering ,installation and commissioning project . • After completion of core retrofit, Engineering Change Orders were issued for reliability/performance enhancing options. • Schedule is presently stretched due to Eng Change Orders (ECOs) for system modifications that will enhance the operation and maintenance of our plant/system.
Bidders • Basically all the reputable names in the Control Systems industry sent a bid: • Westinghouse* • Honeywell • ABB* • Allen Bradley • Woodward Governor Co • Tri-Sen • Bailey Controls • Boyce Engineering • HSDE Inc
Successful bidder :HSDE • Who is HSDE? The original company Hawkker Siddeley Dynamics Engineering developed the Digicon ACE system which is presently installed on our machines. British Aerospace , who bought Hawkker Siddeley kept the intellectual property rights to the name ,”Hawkker Siddeley DynamicsEngineering”
Who is HSDE? (cont’d)Vosper Thornycroft Controls bought the Controls Dept of Hawkker Siddeley from British Aerospace but had no access to the name.Hence “HSDE” is just four initials.HSDE Inc is the North American subsidiary of HSDE LTD of the UK whose parent company is Vosper Thornycroft Controls.
Digicon ACE Technology • 32-bit RISC based system • Originally built for Aero Derivative Gas Turbines aboard British Frigates. • Modular to minimise repair time. • High speed control algorithms • Interfaceability to standard PCs and third party user configurable HMI software ( currently use Wonderware Intouch) • Ease of “Networkability” and remote control options.
Requirements • Initial contract specified: -- the control system retrofit of eight (8) gas turbine generator sets at Pt.Lisas Power Station (PTLS 5 to PTLS12) -- New system to provide dual redundant fiber optic network Distributed control on failure of any HMI workstation. Bently Nevada 3300 dual vibration monitoring with X-Y shaft monitoring and serial interface to new controller.
Requirements (cont’d) • Vibration trip multiply for start-up transient critical speed operation. • Connectability for Bently Nevada ADRE 3 DAIUs for vibration condition monitoring and shaft balancing data. • Installation of SCADA system in 66KV and 132 KV Switchyard for monitoring busbar parameters, all transmission lines and interbus transformers. • Integration of machine controls into a Plant Loadshare system with special algorithms for Steel Mill loading, clock cycle correction, station base loading etc,
Modifications • During the engineering and design phase of the project Engineering Change Orders(ECOs) were issued namely for additional features that were cost effective enhancements to old problems or shortcomings in the existing control systems: • Replacement of existing R-65 servo valve • SQL 10-user license database for logging of all machine parameters and archival storage .
Implementation • Initially the first of each machine type was done on a minor planned outages. On successful proving out of the design, all others were done during scheduled machine major outages thereby minimising outage time. • Four (3) Westinghouse and one (1) ABB machines were retrofitted in one year.
Significant benefits • Improved reliability • Significantly increased monitoring visibility • Electronic data archiving and retrieval • On-line availability of key machine parameters for statistical or engineering analysis • Second sourcing availability of some key components
Significant benefits ( cont’d) • Interchangeability of controllers between machines • Reduction in volume of spares held • Extended Mean Time Between Failures(MTBF)(wires,conns,comps) • Program loading (from 4 Hrs to 4 sec) • Shorter Mean Time to Repair(MTTR) • Standardised training requirements for all units. • System expandability...
Significant benefits ( cont’d) • Shaft centerline vibration signatures from machine mounted probes. • Dual vibration readout per bearing: failsafe 2 to trip. • Shaft balancing data • Ability to make logic program changes • Ability to monitor/log all machine parameters • Additional operating parameters : rolldown time,start-up time,troubleshooting tools
Situation at the start of project • excessive machine trips ( 100 trips in ‘95 at PTLS )
Other System Offerings • Automatic System power line-frequency control • System clock control • Economic Load Despatch • Compressor Surge margin monitoring • Anti-surge protection on ABB m/cs • On-line machine heat rate,efficiency • Raw data for Hot Section Parts Tracking
Special thanks to Reynold Ramnarinesingh , present Maintenance Manager at the Penal Power station, who was PowerGen’s lead on this project and whose leadership and diligence was a contributor to it’s successful implementation.