Latest Power Plant Control System - Hitachi Global

1 Hitachi Review Vol. 52 (2003), No. 2 101 Latest Power Plant Control SystemOVERVIEW: Along with advances in System component technologies,modern state-of-the-art Power Plant Control systems are being developedby incorporating such advanced technologies as extensive digitization ofhigh-speed Control circuits, interconnection with other equipment over openinterfaces, and a repertory of diverse multiplexed systems. Based on HitachiIntegrated Autonomic Control System (HIACS), Hitachi , Ltd. has developedand deployed a wide range of leading-edge Power Plant Control systemsincluding gas turbine Control systems, steam turbine Control systems, andgenerator excitation Control KameiTakashi TomuraYoichi KatoINTRODUCTIONBESIDES providing a stable source of electrical Power ,the modern Power Plant must also be highly efficient,provide good operability, and have minimal adverseeffects on the environment.

2 Meeting these demandingrequirements calls for Plant supervision and operationsthat are more advanced and at the same time moreintuitive and easy to use. And considering the ongoingtrend toward liberalization of the energy market, it isalso essential to hold down Plant construction costsand reduce Plant construction were the background factors motivatingHitachi s development of supervisory and controlsystems that not only continue to support excellentreliability but also provide good cost-effectivenesswhile minimizing the workload involved in plantoperation and maintenance. Our most recent powerplant Control systems are based on Hitachi IntegratedAutonomic Control System (HIACS), the Company scomprehensive supervisory and Control System that hasbeen extensively deployed and has an excellentreputation for reliability and article will describe several of these leading-edge Control systems: the gas turbine Control systemHIACS-MULTI, the steam turbine Control systemHitachi Turbine Start up System 2000 (HITASS-2000),and the generator exciter Control System FEATURES OF THE NEWCONTROL SYSTEMSH itachi s new Control systems leverage the latesttechnologies in HIACS series products.

3 (1) Digitization of high-speed Control circuitsControl circuits such as servo valve Control circuitsrequiring high-speed arithmetic operation areimplemented with digital circuits that operate using aPCM (programmable Control module). This has notonly enabled us to implement the Control equipmentmuch more compactly, it also permits personnel tomodify and adjust Control setting using a maintenancetool, which greatly simplifies these operations.(2) Open interface-based interconnectionsHitachi s Latest Control systems can be intercon-nected to other systems and equipment using the serialinterface standard RS232, TCP/IP (TransmissionControl Protocol/Internet Protocol), and other general-purpose interfaces.(3) Diverse System repertoryA rich repertory of Control System products hasbeen assembled that meets the diverse needs of ourcustomers. The Control System panel has also beenimplemented very compactly so it can be installed innewly constructed plants or easily retrofitted in existingpower TURBINE Control SYSTEMHIACS-MULTIHIACS-MULTI SeriesThe HIACS-MULTI series provides acomprehensive gas turbine Control System that includesgas turbine Control and protection, generatorprotection, and generator excitation Control System is available in a range of sizes andconfigurations, thus providing a good repertory ofproduct options tailored to different customers needs(see Table 1).

4 System ConfigurationThe basic HIACS-MULTI System includes an HMI(human-machine interface) that enables plantLatest Power Plant Control System 102supervision and operation from PC (personalcomputer). A remote HMI can be added in the controlnetwork to interconnect multiple HMIs. The HMI nowincludes a built-in maintenance tool for diagnosing andmaintaining CPU (central processing unit) programs,so each HMI has the ability to perform a full range ofsupervision, operations, and maintenance functions(see Fig. 1).The servo valve Control in HIACS-MULTI isconfigured using digital circuits, so operators can nowmonitor Control logic online. The servo valves arecalibrated by commands from the HMI, thus it is veryuser-friendly and , HIACS-MULTI can be interconnected tothe DCS (distributed Control System ) or otherequipment over such general-purpose interfaces asRS232 or SystemThe HMI for HIACS-MULTI is a graphicalinterface that runs on the Windows* operating provides straightforward easy-to-use menu optionsfor Plant operation, monitoring, annunciation, displayof trends data, servo valve calibration, and othercapabilities (see Fig.)

5 2).Retrofitting the Control System withHIACS-MULTIH itachi was recently commissioned to retrofit thePT Pupuk Sriwidjaja (PUSRI) No. 2 gas turbinegenerator in the Republic of Indonesia with theHIACS-MULTI Control System (see Fig. 3). Hitachisupplied this Plant some three decades ago in 1973. Inthis refurbishment, the existing analog gas turbinecontrol System , the generator excitation Control System ,and the generator protection System were all replacedby the HIACS-MULTI 700 System . This retrofit projectwas very successful, and the HIACS-MULTI systemis now operating smoothly at the PUSRI 1. Overview of the HIACS-MULTI SeriesA full repertory of advanced products are tailored to differentcustomer needs.* Windows is a registered trademark of Microsoft Corp. in the andother 2 Screenshots of the HIACS-MULTI HMI (OnlineMonitoring Displays for Exhaust Gas Temperatures and ControlLogic).

6 With a range of menu options, the HMI offers an intuitive andeasy-to-use user 1 Typical System Configuration of the HIACS-MULTI , operation, and program maintenance from a singleHMI Control (simplex)GT Control (triple redundant)Generatorexcitation controlGeneratorprotectionHIACS-MULTI 100 HIACS-MULTI 200 HIACS-MULTI 300 HIACS-MULTI 500 HIACS-MULTI 700 HIACS-MULTI 700 (S)554445545444555544445554GT: gas turbine4: Provided5: Not providedRemote HMIC entral Control roomLocal HMIC ontrol panel* 2 out of 3 is a voting logic that produces an output by selecting the majority vote from 3 out of 3* Network100 (optical fiber cable)PCMPCMPCMSVD: servo valve driver moduleC-PIO: common process input and outputHitachi Review Vol. 52 (2003), No. 2 103 FEATURES OF NEW STEAM TURBINECONTROL System HITASS-2000(1) System configurationThe main component elements of the steam turbinecontrol System are the speed/load Control unit, the servovalve Control unit, the steam turbine automatic start-up Control unit, and the turbine protection unit.

7 Thesystem has been enhanced by digital circuits in thePCM for servo valve Control , which previously hadbeen implemented by hard-wired 4 is a schematic showing the configuration ofthe new steam turbine Control System HITASS-2000.(2) digital servo controlDigital servo Control circuit in the PCM enablesservo valve calibration easier due to the controlparameter tuning capability by Control logic is also enhanced by implementing thecurrent converter, the oscillator, and the rectifier circuitas a single printed circuit board to minimize hardwareadjustments.(3) Steam turbine protection circuit interlock unitThe steam turbine protection circuit is fundamentallyFig. 4 New Steam Turbine ControlSystem Configuration (DualControllers).With far more extensive digitization,a new compact and highly reliablesteam turbine Control System hasbeen developed that replacesconventional servo valve controlcircuits and steam turbine protectioncircuits.

8 (a) Appearance of the Control equipment(b) Trend display(c)Operation and monitoring displayFig. 3 Screenshots and Appearanceof the Control System for the PTPUSRI No. 2 Unit Gas TurbinePower Plant in the Republic Control System , that has been inservice since Hitachi initiallysupplied the gas turbine Plant backin 1973, was recently replaced byHitachi s state-of-the-art digitalcontrol : Control electronics UD: unit driver AO: analog outputController A(speed/load Control )Controller B Same as leftAutomatic startup Control ,common, steam turbine protectionSoftware simulatorSpeed/load controllerDigital servo Control PCMC urrent converterDigital servo controllerOscillatorValve positiondetector AValve positiondetector BDetectorTrip solenoid valveServo coilI/OI/OCEUDAIAOR ectifier2 out of 3 Trip solenoid valve Control circuitAIDIDOS team turbine protective interlock unitUDSteam turbine protection PCMCEI/OTurbine automatic startup/common controllerLatest Power Plant Control System 104important for safeguarding and protecting the plantfrom serious damage and is therefore implemented asa digital triple-redundant System to ensure the higheststandard of steam turbine protection logic is processed inthe PCM, while the I/O (input and output) component(AI: analog input.)

9 DI: digital input) for detecting tripfactors and the trip signal output component (DO: digital output) are implemented as separate units withtriple redundancy. By implementing these functionsas separate units, they are completely independent andisolated from other functions. This means that the plantsteam turbine protection circuit can be kept runningeven when the other functions fail.(4) MaintenanceAs a result of more extensive digitization, theinternal processing state of the PCM can be monitoredusing the Control System maintenance tool, and thisimproves the maintainability of the Plant . Alarmsignals (including steam turbine protection circuits)are interfaced to the computer over a networkconnection, which enables the number of interfacecables to be reduced. In addition, verification andtesting of turbine speed and load Control functions havebeen simplified with a software simulator function thatincludes a built-in model of the steam turbine.

10 Usingthe simulator, actual servo valves also can be drivenfor the Control function OF NEW digital GENERATOREXCITATION System VCS-6000(1) The number of thyristor panels can be increasedor deceased to accommodate a full range of generatorcapacities from small to large (600-MVA class), whichsimplifies the construction of different scale plantfacilities.(2) Control systems can be implemented as eithersimplex or as dual systems, so systems can be moreclosely tailored to users needs.(3) Maintainability, reliability, and performance areupgraded with the development and deployment ofVCMI (voltage Control module integrated), a singleprinted circuit Control board that integrates voltagecontroller, logic controller, and GPG (gate pulsegenerator).(4) Development and adoption of two new interfaces GDIO (gate driver and input and output) for thethyristor signal interface and RDIO (remote digitalinput and output) for the I/O interface which permitsthe use of optical signals that are practically immuneto noise between VCMIs.