Hello learners. Welcome to this topic on, Intelligent Electronic Devices, that is IED in SCADA. Devices that have single or multiple microprocessors integrated with them are called Intelligent Electronic Devices. It's main tasks involve the transmission or reception of data or control signals to or from an external device. Transducers, relays, control units, etc. can be the external device in consideration with the whole system. These are key part of industrial control system. Industrial control systems are used for the purpose of advanced power automation. That's how these are useful in supervisory control and data acquisition systems or SCADA system, distributed control system or DCS, as a crucial component. We have earlier seen that an IED is a microprocessor- based device that establishes interaction with external peripheral devices. It interfaces with the outside world regarding the transfer of data and signals. This innovation in the power system is an important one. This has brought in plenty of changes in power monitoring, protection, and control. Hence, it is used enormously in power system automation for the purpose of monitoring, protecting, communicating, controlling metering, etc. They have excellent computing power. They can record a sequence of events. This enables analysis of fault that is useful to fault recognition, waveform, and measuring the power quality. Because of these various upward functions, it has become a crucial component in the automation of substitutions and efficient monitoring in power delivery systems. To be simple and precise, without IEDs, power system automation seems to be impossible. The architectural design ensures excellent features like flexibility, adaptability, multipurpose, modular nature, robustness in communication capabilities. Let us now understand the operation of each building block separately in sequence. Usually, IEDs are to be provided by two power supplies from two different sources. The first one is called as the primary source. The second source is called as the auxiliary power supply. It's a backup power supply. IEDs always need an excellently power supply. IEDs operate with the power supply ranging from 15-150 volts DC, that is direct current or 110-130 volts AC, alternating current. Let us now look at analog inputs, digital inputs, and analog outputs. When compared with the relays where inputs is provided by current or potential transformer, that is CT or PT, IEDs get inputs from sensors. Digital inputs are either commands or status information. Certain IEDs may need potential-free contact. Some of the IEDs may understand logic 0 or logic 1, where zero is considered as negative voltage, and one as positive voltage respectively. In the programmable type of IEDs, normally, transducers are used to get the output. The output can be active or passive in nature. If it is passive output, then it needs an external power supply. In these, the potential free contexts can be normally open or normally closed or solid- state contacts. Digital outputs are also commands, or status information. It is better to checkup on the capability of switching. IEDs have faster real-time data transferring and receiving ability as they can use multiple ports. IEDs are designed to operate on analog input, analog output, digital input and digital output. Integration of various individual functions into a single unit is supported by IEDs. Within it, an IED has electromechanical relays, wiring, control switches, and many more. They also offer some auxiliary functions. They are monitoring, data accessing and testing and analysis. IED can monitor self-circuits and external circuits. IED as the events are occurring. Check the real-time synchronization of the events. IEDs can access the data present locally and at distance substations. To test, report and fault analysis, it has certain software. Programmable logic controller functionality is also offered by the IEDs. So far, we have seen various facilities or features offered by IEDs. They are quite appreciable. From this, we can understand that its architectural design is also equally important. This helps to achieve proper programming, commissioning, and maintaining the IEDs. IEDs hardware needs to be designed in a bit that future changes can be adopted. Plug-in type cards are used in order to support maintenance. Such plug-in type of cards enables use of removing or replacing the IEDs from the panel without disconnecting and terminating the wires. The software of the IEDs should help easily analyze the performance and easily configure the desired functions individually. It also supports the selection of required functions and hides the not needed functions. It enables the following. Each function is defined one at a time by a separate set of logical inputs and outputs, setting times, even reporting features. Presently, IEDs are produced with favorable factors like Waveform Capturing, Disturbance Analyzing, Metering, and Programmable Logic Capabilities. These factors remove the requirement of additional PLCs. This module becomes extremely important as the manufacturers use different communication protocols. In present-day conditions, the IEDs have open communication architecture and support with the different protocols to facilitate multi-port communication and flexibility are required. In addition, it is also required to have a serial electrical port, remote access port, and optical port. This open protocol support, interoperability is most preferable. Various protocols are supported by the communication modules. They are providing a replacement facility in the field if a change in communication requirement is needed. As communication module has the multiport ability due to multiport communication ability, and IED can communicate with substation and various other IEDs in the network simultaneously. IEDs have been deprived extensively in Power automation systems recently, and the shift from RTUs to IEDs is evident due to the integration on long distance communication features of the IEDs. The IED handles additional features like self and externals circuit monitoring, real-time synchronization of the event monitoring, local and substitution data access, and an entire range of software tools for commissioning, testing, even reporting, and fault analysis. Load profiling is another metering activity that can be achieved using IEDs where the power factor profile, ampere demand, long term RMS voltage value, harmonics, THD, and phase sequence can be monitored and can be used for load profiling along with the data logging facility. The power quality analyzer eliminates the digital recorders because it can do waveform recording during a voltage dip, voltage swell, inrush current measurement , and distorted waveform. Event reporting can be easily done by IEDs eliminating the sequence of events or SOE recorders. The electromechanical release as well as normal energy meters did not have such capability. Your minimum number of I/O tags that is input-output. Handling capacity shall be 100 I/O tags and 20,000 data points. FRTU have an in-built optical coupler to isolate field signals for digital inputs. FRTU shall monitor suitable features of external battery availability check through potential-free contact as DI signal to FRTU and suitable provision in FRTU to supervise and prevent accidental serious discharge of the battery. FRTU consist of the following parts; analog inputs, 6/8 input AI card, control outputs, power supply, FRTU requirement, AC input supply, DC output required. With this, we come to the end of this session. Thank you.
