1584 IEEE TRANSACTIONS ON POWER SYSTEMS.VOL.19,NO.3.AUGUST 2004 a power system,both during its normal functioning and under fault conditions,as this is the basic tool for fault diagnostics. 3)Input/Output Units:At present the system has 216 input/output channels,including that of both the DPU and RTU.The analog inputs comprise of the signals coming from the voltage and current transducers con- nected to the various field devices like the 3-phase transmission line,3-phase load,etc.The digital in- puts/outputs are the capacitor bank on/off positions in the substation and the circuit breaker positions on the transmission line and the load.Apart from these,there are pulse inputs and outputs. 4)Data Highway:The laboratory incorporates industry stan- Fig.3.The processor,with the Ethernet,Profibus,and Modbus modules dard networking.It has an Ethernet data highway(coaxial cable)operating at 10 Mbps and is currently supporting The RTU.DPU and the input/output units are intercon- a network of four operator stations and two engineering nected through the Profibus module,as shown in Fig.3. stations along with the DPU and the RTU,all connected The DPU has the Modbus module for dedicated commu- in bus topology.The DPU passes real time data to the op- nication with Intelligent Electronic Devices(IEDs). erator and engineering stations via the Ethernet through 2)Remote Terminal Unit(RTU):The SCADA/EMS labo- customized software.The I/O units are connected to the ratory has a single RTU that can be stationed at a re- processor through the Profibus.The Modbus module con- mote location.Presently in the absence of a sufficiently nects the Intelligent Electronic Device,the Energy Ana- remote field,the RTU is functioning inside the labora- lyzer,to the AC800F.The Modbus is incorporated in the tory itself.The RTU is also equipped with I/O channels system for performing dedicated tasks and for better un- (digital,analog and pulse)for capturing the field data, derstanding of the industrial buses. and has the modem for communicating on RS485 link. 5)Operator and Engineering Station:The SCADA system Like the DPU,the RTU is also configured around a 32-bit has six Pentium-IV Computers(running in the environ- RISC processor AC800F.The RTU communicates to the ment of Windows 2000)acting as the operator stations master SCADA system(DPU)through a Profibus.Since and engineering stations,so that,at a given time,a max- the DPU and RTU have the same hardware configuration imum of 10 students/trainees can work in the laboratory, and are at the same location,they can act as a redundant two on each station,one station is left for faculty members system at any time,to depict the actual control room ex- and R&D work.Each of the four operator stations pro- perience. vides a customized,interactive,graphic user interface,de- The DPU and RTU are currently performing the fol- signed using modern software programming techniques. lowing functions in the laboratory: The entire field can be monitored and controlled from a)Data acquisition,system monitoring and control: the operator stations.Presently,as the field equipments The DPU and RTU acquire data(digital,analog and being monitored are not very vast,each operator station pulse)from the field equipment connected to the covers the entire field,but in case of a vast field,each various input channels.These data are then passed operator station can be configured to perform dedicated on to the processor via the Profibus.The processor monitoring of different sections of the field. performs analytical calculations on these data and Two Pentium IV computers are serving as the engineering transmits them to the engineering and operator sta- stations for the system.The engineering station runs the engi- tions via the Ethernet.The various operators can neering software,programmed using Visual Basic 6.0.The com- thus monitor the field signals viz.voltage,current, missioning,adding new hardware,changing the tag settings,and frequency,temperature etc from the control room. associated tasks are performed at the engineering station using The DPU also has analog,digital and pulse output the engineering software modules,through which the operator can give con- trol signals from the operator station to the field de- vices,e.g.,a pulse output signal to rotate the stepper B.System Software motor. Currently,the laboratory utilizes two system software b)Sequence of Events Recording(SOE):All the data programs for better understanding and proper utilization of in the DPU comes with a time stamping.The scan the product available in the market.The first one is hardware rate for digital data is usually 2 ms and for analog specific and dedicated software,whereas the other one is an data it is 10 ms.The scan time can be set to0.5 ms,1 open-ended system software,which can communicate with any ms,2 ms etc.as per the process requirement.SOE hardware device.This is to make the laboratory much more will provide the students a clear understanding of generalized,rather than constrained to a specific hardware.The the various phenomena and events associated with SCADA software being used in the laboratory has provision1584 IEEE TRANSACTIONS ON POWER SYSTEMS, VOL. 19, NO. 3, AUGUST 2004 Fig. 3. The processor, with the Ethernet, Profibus, and Modbus modules. The RTU, DPU and the input/output units are intercon￾nected through the Profibus module, as shown in Fig. 3. The DPU has the Modbus module for dedicated commu￾nication with Intelligent Electronic Devices (IEDs). 2) Remote Terminal Unit (RTU): The SCADA/EMS labo￾ratory has a single RTU that can be stationed at a re￾mote location. Presently in the absence of a sufficiently remote field, the RTU is functioning inside the labora￾tory itself. The RTU is also equipped with I/O channels (digital, analog and pulse) for capturing the field data, and has the modem for communicating on RS485 link. Like the DPU, the RTU is also configured around a 32-bit RISC processor AC800F. The RTU communicates to the master SCADA system (DPU) through a Profibus. Since the DPU and RTU have the same hardware configuration and are at the same location, they can act as a redundant system at any time, to depict the actual control room ex￾perience. The DPU and RTU are currently performing the fol￾lowing functions in the laboratory: a) Data acquisition, system monitoring and control: The DPU and RTU acquire data (digital, analog and pulse) from the field equipment connected to the various input channels. These data are then passed on to the processor via the Profibus. The processor performs analytical calculations on these data and transmits them to the engineering and operator sta￾tions via the Ethernet. The various operators can thus monitor the field signals viz. voltage, current, frequency, temperature etc from the control room. The DPU also has analog, digital and pulse output modules, through which the operator can give con￾trol signals from the operator station to the field de￾vices, e.g., a pulse output signal to rotate the stepper motor. b) Sequence of Events Recording (SOE): All the data in the DPU comes with a time stamping. The scan rate for digital data is usually 2 ms and for analog data it is 10 ms.The scan time can be set to 0.5 ms, 1 ms, 2 ms etc. as per the process requirement. SOE will provide the students a clear understanding of the various phenomena and events associated with a power system, both during its normal functioning and under fault conditions, as this is the basic tool for fault diagnostics. 3) Input/Output Units: At present the system has 216 input/output channels, including that of both the DPU and RTU. The analog inputs comprise of the signals coming from the voltage and current transducers con￾nected to the various field devices like the 3-phase transmission line, 3-phase load, etc. The digital in￾puts/outputs are the capacitor bank on/off positions in the substation and the circuit breaker positions on the transmission line and the load. Apart from these, there are pulse inputs and outputs. 4) Data Highway: The laboratory incorporates industry stan￾dard networking. It has an Ethernet data highway (coaxial cable) operating at 10 Mbps and is currently supporting a network of four operator stations and two engineering stations along with the DPU and the RTU, all connected in bus topology. The DPU passes real time data to the op￾erator and engineering stations via the Ethernet through customized software. The I/O units are connected to the processor through the Profibus. The Modbus module con￾nects the Intelligent Electronic Device, the Energy Ana￾lyzer, to the AC800F. The Modbus is incorporated in the system for performing dedicated tasks and for better un￾derstanding of the industrial buses. 5) Operator and Engineering Station: The SCADA system has six Pentium-IV Computers (running in the environ￾ment of Windows 2000) acting as the operator stations and engineering stations, so that, at a given time, a max￾imum of 10 students/trainees can work in the laboratory, two on each station, one station is left for faculty members and R&D work. Each of the four operator stations pro￾vides a customized, interactive, graphic user interface, de￾signed using modern software programming techniques. The entire field can be monitored and controlled from the operator stations. Presently, as the field equipments being monitored are not very vast, each operator station covers the entire field, but in case of a vast field, each operator station can be configured to perform dedicated monitoring of different sections of the field. Two Pentium IV computers are serving as the engineering stations for the system. The engineering station runs the engi￾neering software, programmed using Visual Basic 6.0. The com￾missioning, adding new hardware, changing the tag settings, and associated tasks are performed at the engineering station using the engineering software. B. System Software Currently, the laboratory utilizes two system software programs for better understanding and proper utilization of the product available in the market. The first one is hardware specific and dedicated software, whereas the other one is an open-ended system software, which can communicate with any hardware device. This is to make the laboratory much more generalized, rather than constrained to a specific hardware. The SCADA software being used in the laboratory has provision