SCADA SYSTEM OVER VIEW, ARCHITECTURE MAIN COMPONENTS T Srinivas, Chief Manager, SRLDC 1 SCADA SYSTEM OVER VIEW ARCHITECTURE MAIN COMPONENTS 2 SCADA :Supervisory Control and Data Acquisition It is the system responsible for gathering, processing, and displaying information about the state of a monitored system. From a SCADA control center, operators and application programs can oversee and change the operating state of monitored devices. 3 4 Southern Regional Load Despatching Facilities RLDC Bangalore 2 Sec SLDC Bangalore Hyderabad Kalamassery Chennai SCC UTP 2 Sec Sub LDC LGR GTR 10 Sec CDP WGL RTU RTU VIJ TVM TVM MDI ERD RTU RTU RTU RTU INT SCADA RTU RTU RTU RTU RTU 5 Scada System - Overview TYPICAL SCADA SYSTEM SCADA H/W & S/W C TX O RX M E M Q N P T CONTROL CENTRE MEDIA COMMN MEDIA C O M M N TX Rx E Q P T R T U T R A N S D U C E R P A N E L C &R PANEL FIELD UNIT / RTU SUBSTATION / GEN STATION 6 Scada System - Architecture • First Generation – Monolithic • Second Generation – Distributed • Third Generation – Networked 7 Scada System - Architecture MONOLITHIC SCADA SYSTEM 8 Scada System - Architecture MONOLITHIC SCADA SYSTEM Computing Centered with Main Frame Non existant of Networks Centralised System Standalone sytem 9 Scada System - Architecture DISTRIBUTED SCADA SYSTEM 10 Scada System - Architecture DISTRIBUTED SCADA SYSTEM • Advantage of developments and improvement in system miniaturization and Local Area Networking (LAN) technology to distribute the processing across multiple systems. • Multiple stations, each with a specific function, were connected to a LAN and shared information with each other in real-time 11 Scada System - Architecture DISTRIBUTED SCADA SYSTEM • Communications processors, primarily communicating with field devices such as RTUs. • operator interfaces, providing the human-machine interface (HMI) for system operators. • calculation processors or database servers. 12 Scada System - Architecture DISTRIBUTED SCADA SYSTEM • Network-connected systems served not only to increase processing power, but also to improve the redundancy and reliability of the system as a whole. • Distributed architecture often kept all stations on the LAN in an online state all of the time. 13 Scada System - Architecture NETWORKED SCADA SYSTEM14 Scada System - Architecture NETWORKED SCADA SYSTEM • The major improvement in the third generation is that of opening the system architecture, utilizing open standards and protocols and making it possible to distribute SCADA functionality across a WAN and not just a LAN. • There are still multiple networked systems, sharing master station functions. There are still RTUs utilizing protocols that are vendor-proprietary. 15 Scada System - Architecture NETWORKED SCADA SYSTEM • Utilization of off-the-shelf systems makes it easier for the user to connect third party peripheral devices (such as monitors, printers, disk drives, tape drives, etc.) to the system and/or the network. • Because of “open” or “off-the-shelf” systems, SCADA vendors have gradually gotten out of the hardware development business. 16 Scada System - Architecture NETWORKED SCADA SYSTEM • Advantage of the use of WAN protocols such as the Internet Protocol (IP) for communication between the master station and communications equipment. • Advantage brought about by the distribution of SCADA functionality over a WAN is that of disaster survivability. 17 Control Room Hardware 18 Control center Architecture RTUs on 60870-5101 Protocol RTUs on Other Protocol Serial Cards (including 8 pair of modems) /Splitters CFE Servers NETWORK Router cum Firewall 2 Nos. 2 No. RTU on 104/ PMU 0n C37.118/ other IP devices DATA ACQUISITION VLAN SCADA NAS Storage LCD / Video Projection Database Servers SCADA Servers Historian Renewable Control / mon SCADA/EMS Routers at RLDCs and SLDC Router cum Firewall 2 Nos. Developmental Workstation ICCP Servers DTS Server Printers ISR Servers 2 No. NMS Servers (B/W & Color) UPS, CMC, RD, PDS, ISR, NMS / Management LAN UPS Monitoring System CMC Identity Server Server Management Console Replica Servers Dual Monitor Training Consoles WorkStation LAN RD, CMC, UPS & SERVER MANAGEMENT LAN Programmer Development Server (1 Nos.) VL A N (DMZ) PDS, ISR, NMS LAN Report Generation EMS Servers GPS , Time and Frequency Displays SO WorkStation (Dual Monitor) Remote WorkStation for Boss (Single monitor SO WorkStation No controls) (Dual Monitor) SO WorkStation (Dual Monitor) SO WorkStation (Dual Monitor) IT application servers (DMZ) Secure VPN Corporate NAS Storage ABT Scheduling, Poc & Market Operation Energy accounting Web Servers FTP Server CORPORATE LAN PC PC PC PC Fig 1 Redundant Internet from different service provider PC PC 19 Scada System – Main Components • Field Data Interface Devices • Communication Network • Central Host Computer • Operator Workstations and Software Components 20 21 Scada System – Main Components Field Data Interface Devices • "eyes, ears and hands" of a SCADA system • Before any automation or remote monitoring can be achieved, the information that is passed to and from the field data interface devices must be converted to a form that is compatible with the language of the SCADA system. 22 Scada System – Main Components Field Data Interface Devices • To achieve this, some form of electronic field data interface is required – RTU • RTU - primarily used to convert electronic signals received from field interface devices into the language (known as the Communication protocol) used to transmit the data over a communication channel. 23 Scada System – Main Components Field Data Interface Devices • • • • Sensors/transducers that convert physical parameters to electrical signals. Signal conditioning circuitry to convert sensor signals into a form that can be converted to digital values. Analog-to-digital converters A Scada system to process this digital data. 24 HARDWARE CONNECTIVITY DIAGRAM FOR SCADA AT SUBSTATION / GEN.STATION RS232 PORT TRANSDUCER PANEL REMOTE TERMINAL UNIT MAIN CPU BOARD COMMN BOARD TRANSDUCER I/P TERMINAL PT SEC 110VAC PSU MW MVAR F R O M VOLT CT SEC 1 AMPS S W I T C H Y A R D F I E L D TRANSDUCER O/P TERMINAL A N A L O G D I G T A L I/P I/P TERMINAL BLOCK TERMINAL BLOCK C O N T R O L O/P TERMINAL BLOCK EVENT LOGGER PANEL D R I V E R R E L A Y 25 Basic Data Acquisition CT CB Pannel control PT Potential Free Contact Field Clos e Trip TRANSDUCER DAS NO Coil for Close RTU Ang In RTU Dig In NC Coil for Trip RTU Dig out 26 TRANSDUCERS CLASSIFICATION INPUT 0-10mA, 4-20mA, 0-5mA 0-5v,0-10v OUTPUT IMPEDANCE VOLTAGE/CURRENT OUTPUT SELF POWERED/AUXILARY POWERED 500Ω,1000Ω,2000Ω ACCURACY 0.2 CLASS, 0.5 CLASS, CLASS 2 AND ABOVE 27 A/D CONVERSION AT RTU LEVEL (16 BIT ADC). FOR MW / MVAR TRANSDUCER: INPUT: PT SEC PHASE TO PHASE : 110VAC CT SEC TWO PHASE CURRENT (R & B): 1 A. OUTPUT : 4 – 20mA(TRANSDUCER OUTPUT) IN ADC: AT 4mA = 6553 Count AT 20mA = 32767 Count 12mA IS THE CENTRE POINT. (+/- 0.1% IS THE ACCEPTABLE RANGE OF ERROR ON FULL SCALE) 28 TELEMETRY FOR SCADA P P Q SS P DS SS V F V SS F DS MW Q MVAR P Q O SS O SS DS SS SS SS SS DS DS Q TAP POSITION FREQUENCY SS SINGLE STATUS ISOLATOR POSIITION, PROTECTION, LOSS OF VOLTAGE DC Q SS F DS SS SS SS P DC SS SS SS Q DS V VOLTAGE DOUBLE STATUS CIRCUIT BREAKER POSITION DIGITALCONTROL CIRCUIT BREAKER CONTROL THE PARAMETERS ARE FOLLOWING STATIONS : MONITORED FOR •Substations 220 KV and above •132/110KV AC Interstate Tie lines and in loop of 220 KV transmissions system •Generating Station above 50MW capacity. •Significant stations identified by constituents 29 Scada System – Main Components Communications Network • Intended to provide data transfer between the central host computer servers and the fieldbased RTUs • The Communication Network refers to the equipment needed to transfer data to and from different sites. The medium used can either be cable, telephone or radio. 30 Scada System – Main Components Communications Network • Historically,SCADA networks have been dedicated networks • With the increased deployment of office LANs and WANs as a solution for interoffice computer networking, there exists the possibility to integrate SCADA LANs into everyday office computer networks. 31 Scada System – Main Components Communications Network The foremost advantage of this arrangement is that there is no need to invest in a separate computer network for SCADA operator terminals. In addition, there is an easy path to integrating SCADA data with existing office applications, such as spreadsheets, work management systems, data history databases. 32 Communication System RAMAGUNDAM PEDAPALLI DURSHED JAMMIKUNTA GAJUWAKA WARANGAL VIZAG SWS SHAPURNAGAR VIDYUTH SOUDHA GHANAPUR BOMMUR KAKINADA CH.GUTTA VTPS HYDERABAD 400 BHIMADOLE N’SAGAR PH VIJAYAWADA TALLAPALLI SRISAILAM PH SRISAILAM LBPH KURNOOL APSEB Lingasugur HUBLI SOMAYAJULAPALLI RTU’S 82 N GOOTY MUDDANOOR RTPP DAVANAGERE CHINAKAMPALLY ANANTHAPUR BANGALORE KEB CHENNAI RTU’S SOMANAHALLI KUMBALGODI PONDY SRIPERUMBUDUR RTU’S P 05 SP.KOVIL 22 VILLIANUR PONDY KANNUR-B SALEM400 CENTRAL PANRUTI SALEM230 NEYVELI ERODE SECTOR RTU’S 22 CHIDAMBARAM INGUR KOZHIKODE LEGEND RSCC (1) MYLADUTURAI CPCC (1) PONGALORE UDUMALPET TRICHY TRICHUR NORTH ADANIKOTTAI CHALAKUDI MADURAI400 RTU’S 30 VIAKKAM PALLOM KUNDRA TRIVANDRUM NORTH KARAIKUDI SIVAGANGA MADURAI KAYANKULAM TNEB RTU’S PARIPALLI SLDC (4) SUB-LDC / SCC (14) PUDUKOTTAI THIRUMAYAM KALAMASSERY KSEB KOVILVENNI THIRUVARUR ORTHANADU 40 FIBRE FIBRE FIBRE FIBRE OPTIC OPTIC OPTIC OPTIC LINK LINK LINK LINK 110/132kv (220kv) (400kv) (SEB) 33 links) MICROWAVE LINK (35 Scada System – Main Components Central Host Computer Network of computer servers that provide a man-machine operator interface to the SCADA system. The computers process the information received from and sent to the RTU sites and present it to human operators in a form that the operators can work with. 34 Scada System – Main Components Central Host Computer Operator terminals are connected to the central host computer by a LAN/WAN so that the viewing screens and associated data can be displayed for the operators. SCADA systems are able to offer high resolution computer graphics to display a graphical user interface or mimic screen of the site. 35 Scada System – Main Components Operator Workstations and Software Components Operator workstations are most often computer terminals that are networked with the SCADA central host computer. The central host computer acts as a server for the SCADA application, and the operator terminals are clients that request and send information to the central host computer based on the request and action of the operators. 36 Scada System – Main Components Operator Workstations and Software Components An important aspect of every SCADA system is the computer software used within the system. The most obvious software component is the operator interface or Man Machine Interface/Human Machine Interface (MMI/HMI) package Many SCADA systems employ commercial proprietary software upon which the SCADA system is developed 37 Scada System – Main Components Operator Workstations and Software Components Central host computer operating system Operator terminal operating system Central host computer application Operator terminal application 38 Scada System – Main Components Operator Workstations and Software Components Communications protocol drivers Communications network management software RTU automation software 39 Scada System – Main Components Operator Workstations and Software Components HMI -DAC -UI -DMC -ALARM EVENTS -ICCP -TDS 40 DAC MODULE (FOR SR ULDC) Scans the RTUs cyclically or on demand by the user The periodicity of scan can be defined Analog Data – 10 SECONDS Status Data – By Exception / Integrity check every 10 min SOE Data processing 41 Data types SCADA processes and stores three different types of data: Analog Measurement, Status (CircuirtBreakers and Isolators Positions), and Count data (Like energy, Rainfall during the day etc). 42 Data Type Analog Data : Analogs are numeric values representing the state of variable-state devices, such as power lines, transformers etc In the monitored system a physical variable is usually measured by a transducer, and the output of the transducer is passed through an analog-to-digital (A/D) converter in the RTU . Status Data : Status values represent the state of devices, such as circuit breakers, tap changers 43 Data polling method Analogs are defined as periodic/Cyclic data . The periodicity varies from 10 seconds to 15 seconds depending upon the quantity of data and available bandwidth . Digital input state changes are to be reported spontaneously . The Digital input data have higher priority than Analog values. 44 Data Flow NLDC 45 45 Digital Data Potential free contacts are used to transfer switch position to control centre. 46 Sequence Of Events Sequence of events provides milli secs accurate time of status changes for devices monitored by Remote Terminal Units . The RTU clock is synchronized periodically by the control center clock . Reading its internal clock when a SOE status point changes state . Time stamped digital data stored in RTU buffer and transferred as file or Digital data with time stamped is transferred for SOE 47 UI & DMC The UI subsystem facilitates interface to the User It is through this module, the display, the real time status of the power system are viewed by the user. The status of the hardware & logical devices, the communication with the RTU etc .. are closely monitored and failures are reported. 48 RSCC, BANGALORE CONTROL CENTRE WORK WS2 WS1 WS3 WS4 DUAL LAN Switch WS6 DTS SYSTEM AP-7 FE-1 AP-8 DTS DTS SERVER WS5 FRONT END PROCESSOR S WS7 SERVER STATIONS FE-2 APPLICATION PROCESSOR RAID PNA:POWER NETWORK ANALYSIS AP-1 AP-2 AP-3 AP-4 SCADA AGC DATA BACKUP PNA/ICCP COPS BACKUP SERVER SERVER SERVER SERVER SERVER 34 AP-5 AP-6 COPS: COMPREHENSIVE OPERATION PLANNING AND SCHEDULING ICCP: INTER CONTROL CENTRE COMMUNICATION PROTOCOL RAID:- REDUNDANT ARRAY OF INDEPENDENT DISKS 49 Fig 2.41 50 Alarm/Events & Log Subsystem Responsible for processing alarm & event messages, updating the alarm/events, sending event messages to the log subsystem, acknowledging and deleting alarms and generating application trigger messages 51 52 ICCP Responsible for data transfers between the control centers The data includes real time data, interchange schedules, application program results, operator messages, files and historical data Data flows in a strict vertical direction. The data flows from a Sub-LDC to the SLDC The Sub LDCs attached to the SLDC do not communicate directly with each other nor do they communicate with the RSCC, other SLDCs, the SCC or Sub-LDCs on another SLDC Data flows from the SLDCs/SCC to the RSCC. However, data does not flow directly from SLDC to another SLDC or from a SLDC to SCC. The RSCC acts as an intermediary between the SLDCs and the SCC 53 ICCP DATA FLOW CLIENT SERVER ANALOG/ STATUS POINT ANALOG/ STATUS POINT ICCP POINT ICCP POINT VAR LIST VAR LIST DATA SET TRANSFER SET DATA SET TRANSFER SET ASSOCIATION ASSOCIATION DOMAIN DOMAIN 54 PNA SYSTEM DATA FLOW 55 TDS Long term Storage of data in the system. The type of data include energy accounting data, telemetry from RTUs, schedules, operational planning data, random events such as system alarms, despatcher messages and activity logs. Real time calculations TDS ( Temporal database & archive database ) is built using the SYBASE relational database management 56 TDS Archiving of the stored data – The archiving process copies data from the Temporal database and stores it in a disk file. Archiving can be scheduled to occur or it can be done on demand. Once the disk file is created, it can be manually transferred to any type of off-line storage such as CD or cartridge tape. Configurable Parameters Variable number Variable name Point Number Sample frequency ( 2 seconds – 1 year ) Storage frequency ( 2 seconds – 1 year ) Collection method ( maximum, minimum, summation, average, integration, standard deviation ) Retention period ( 1 month to 1 year depending on the storage frequency ) 57 58 59 60 61 62 63 64 ALARMS 65 ALARMS ANALOG DIGITAL 66 Alarms-Analogs Normal limit-Range of limits which device is considers to be operating normally Reasonability Limit-range of values that SCADA uses to determine whether the value retrieved for the analog is realistic. Forbidden Limit-Range of values that SCADA considers violated when the analog point fall within that range Dead band Limits-On a pair of low or high limits if it is violated the value must rise above the limit by at least the dead band amount before the SCADA consider s the analog to be back within normal limits . 67 Normal Alarms-analogs MW/MVAR/MVA/FREQ/VOLTAGE ALARM LIMIT-OPERATIONAL ALARM LIMIT-ALARMING ALARM LIMIT-EMERGENCY 68 Alarm Limit -MW ALARM LIMIT-OPERATIONAL +/- 1.05*(1.732*V*I*O.8) ALARM LIMIT-ALARMING +/- 1.10*(1.732*V*I*O.8) ALARM LIMIT-EMERGENCY +/- 1.15*(1.732*V*I*O.8) V-NOMINALVOLTAGE I-NOMINAL CURRENT 69 Priority Alarms Alarms are categorized in 8 category Priority 1 -Emergency threshold overshoot and status point alarms of controllable switching devices, ICCP links and other ICCP data exchange related alarms) • Priority 2 -Point alarms of non-controllable switching devices. • Priority 3 -Protection trips and substation alarms • Priority 4 -Alarms relevant to RTU’s, communication lines, and alarms of “unreasonable” category • Priority 5 - “configuration management” alarms, i.e. hardware failures (mimic board, printer, etc.) and software failures • Priority 6 –All Network alarms-state estimator , contingency analysis) and the alarms detected by the generation applications (AGC and LF) • Priority 7 -Scada topology alarms 70 •Priority 8 -HDR, Tagging, Limit Replacement. Flags Gives Source and Quality of data Source of data RTU -----------Telemetered ENTERED-----Manually Entered EXTERNAL----Always to be entered manually INTERSITE-----Data from other site CALCULATED—Calculation tag Quality of data GARBAGE-The data is unreliable. The flag appears when data is uninitialized. SUSPECT-Data is labelled suspect when there is one or more of this flag (OLD, BAD, OVER and RESUSP) REPLACED-Data is labelled replaced when MANREP, ESTREPor REMPL) GOOD-Data is labelled GOOD when it is not GARBAGE, SUSPECT and REPLACED. 71 Flags Unit: - uninitialized. Old:-Could not be retrieved in the last scan Telemetry failure:- communication with RTU failed BAD: - when RTU returns one or more standard test values in the RTU outside the allowed limits. Either Transducer is faulty or there is an RTU malfunctioning. Over Range: - Raw Value Received from RTU is outside the expected Range. Unreasonable:-The converted value has crossed the reasonability limit. Anomalous:-Basically not a data quality Flag .State Estimator considers the above measurement not fit for the solution. Manually replaced:-Replaced by operator 72 Flags State Estimator replaced:-Value for an analog is overridden, or replaced, by state Estimator on operator request. Generalized Calculation: - Value replaced through generalised calculation. Maintenance mode: - The Device has been placed in maintenance mode. NIS:-device not in service. It will not allow scanning or calculation to update the record which is marked NIS Alarm Inhibit: - Alarms for this device inhibited. Remote Suspect:-The value is suspect at source control centre. Remote Replaced:-The value has been replaced by 73 source control centre Historical DATA Recording Historical Data Recording (HDR) function allows you to preserve a time series of any set of analog, status, and accumulator measurements . HDR functions Saves the SCADA measurements in disk files called Historical files. Keeps track of the Historical files that have been created and allows you to delete them. The Database Reconstruction functions allow you to reconstruct or create a Data History listing from the data in the Historical files. The reconstructed database can be moved to the network database for use by other applications. 74 Trend Displays Real Time Trend Display Digital, analog or counter value can be viewed simultaneously in different displays. The information is usually sampled cyclically, stored in memory on a circular buffer and plotted on a window against time. Historical Trend Displays To trend the value (digital, analog counter) with archived data 75 Tagging Tags are free formatted text, which provide critical information to next shift operator . Tags can be provided over digital, analog and counters data-points. Operators can insert, edit or delete any number of tags, if they have privileges to do so. Some operators may only be allowed to view tags. These operations can be done from graphic displays by selecting a dynamic object or from a system list of entities. 76 77 EVOLUTION OF SCADA AT SRLDC EARLY 90s : - Remote Console system i.e Getting Static Picture from Each SEB , displaying Limited values on cyclic telemetry. - DOT dedicated Leased Circuit @1200 baud. - No storage facility. - Operation Message transfer throu’ FAX mile. - Remote Console Terminals used as MMI. 78 REMOTE CONSOLE EVOLUTION OF SCADA AT SRLDC Later 90’s : - Mini-SCADA system installed - One server & 3 MMI system ,Later Dual server system. - Data acquired from 17Nos of 400kV stations by 8-bit Microprocessor based RTU. - Off Line studies. - Local Area Network - Storage on HDD & Backup done through DAT 79 MINI SCADA tapes. EVOLUTION OF SCADA AT SRLDC EARLY 2000 : - INSTALLATION & COMMISSION OF ULDC SCADA SYSTEM. - MEASURANDS ACQUISION INCREASED FROM FEW HUNDREDS TO FEW THOUSANDS. - STORAGE OF VOLUMINOUS DATA. - HIGH SPEED COMMUNICATION LINKS. - Used RISC based Servers & Workstations. - Time stamping at RTU as well as Control Centre is possible with GPS. - Weather station used for EMS studies. 80 SCADA SYSTEM EARLY 90’s AT SRLDC REMOTE CONSOLE MODEM REMOTE CONSOLE REMOTE CONSOLE REMOTE CONSOLE MODEM MODEM MODEM DOT LEASED LINE MODEM MODEM MODEM MODEM ND110 TNEB ND110 APSEB ND110 KEB ND110 KSEB 81 SCADA SYSTEM EARLY 90’s AT SRLDC (Contd …) SRLDC CONTROL ROOM APSEB KSEB TNEB KEB IOCC NLY TS 2 BANGL’R S/S 82 HARDWARE CONFIGURATION OF MINISCADA AT SRLDC AP LD MODEM TNEB LD MODEM KEB LD MODEM KSEB LD MODEM IOCC MODEM S’HALLI MODEM M P C C M P C C MONITOR MMI MMI MMI PENTIUM SERVER 10 P O R T C A R D FRONT END PC M P C C PENTIUM SERVER MPCC – MULTI PORT COMMUNICATION CARD 83