Artificial Intelligence In Power System Author Doshi Pratik H.Darakh Bharat P.

Introduction  Power system has grown tremendously over a few decades.  As the size and complexity of the power system consisting of generators, transmission lines, power transformers, distribution transformers, etc increases the possibility of inviting faults.  The acquisition of data, the processing of those data for use by the operator, and control of remote devices are the fundamental building blocks of all modern utility control systems.

Need of SCADA  In most systems there are locations where operations, must be done from time to time and under specified norms and constraints in accordance with a directed action, but the cost of providing and maintaining an operator attendance all the 24 hours in a day can’t be justified.  The manual process works well for small networks but consumes time, labours and efficiency in large networks & also decreases reliability levels.  SCADA operates as a stand alone, autonomous system, monitoring sensors, displaying data, outputting controls, activating alarms and logging information to facilitate and optimize the plant processes and on-going operations

 SCADA is acronym for Supervisory Control and Data Acquisition. What is SCADA?  SCADA is not a full control system, but rather focuses on the supervisory level.  SCADA systems are used to monitor and control a plant or equipment in industries such as telecommunications, water and waste control, energy, oil and gas refining and transportation.

Fig: Typical SCADA system

Components of a SCADA system  Multiple Remote Terminal Units (also known as RTUs or Outstations).  Communication infrastructure.  Master Terminal Unit (MTU) or HMI computer(s)

Master Station:  The "Master Station" are the servers and software responsible for communicating with the field equipment (RTUs, PLCs, etc), and to control system with the help of HMI.  Dual server is provided to the SCADA system hence server failure does not affect the system.  In larger SCADA systems, the master station may include multiple servers, distributed software applications, and disaster recovery sites.

Human Machine Interface (HMI):  The Human-Machine Interface is a interaction among human & machine to monitor and to control multiple remote controllers, PLC’s and other control devices.  An HMI also linked to a database, to provide trending, diagnostic data, and management information such as scheduled maintenance procedures, logistic information, detailed schematics for a particular sensor or machine, and expert-system troubleshooting guides.

Remote Terminal Unit (RTU):  The RTU connects to physical equipment, and reads status data or analog measurement data, and send out digital commands or analog setpoints.  By sending signals to equipment the RTU can control equipment, such as opening or closing a switch or a setting the rate of transmission of current.  An important part of most SCADA implementations are ALARAMS which are digital status point that has either the value NORMAL or ALARM.

Characteristics of RTU’s DData Networking, DData Reliability DData Security

Communication infrastructure  SCADA systems have traditionally used combinations of radio and direct serial or modem connections to meet communication requirements.  Now Ethernet and IP over SONET is also frequently used at large sites such as railways and power stations.

Hardware Solution’s  SCADA solutions often have Distributed Control System (DCS) components.  “Smart" RTUs or PLCs, which are capable of autonomously executing simple logic processes without involving the master computer, are increasingly used.  A functional block programming language, IEC , is frequently used to create programs which run on these RTUs and PLCs.  IEC are easy to learn and require minimal training

Working of SCADA system  Most of the control is performed automatically by RTUs or by PLCs. Host control functions are usually restricted to basic site overriding or supervisory level intervention.  Data acquisition begins at the RTU or PLC level (meter readings / equipment status reports) and are communicated to SCADA as required.  Data is compiled and formatted in such a way that using the HMI the controller can make supervisory decisions to adjust or override normal RTU (PLC) controls.  SCADA systems include input-output signal hardware, controllers, HMI, networks, communications, databases, and software.

Fig 2: shows basic working of SCADA

Operational philosophy:  Hardware for SCADA systems is generally made durable to withstand temperature, vibration, and extreme voltage, but reliability is enhanced by having redundant hardware and communication channels.

Application’s  Detection of faults and isolation of faulty equipments from healthy equipments.  It not only manages the Power System Infrastructure, but also manages the Information Infrastructure.  It provides uninterrupted power supply.

Conclusions:  The SCADA systems established are playing a vital role in displaying the exact rate at the appropriate time, reliability level and helping a lot in reducing the risks and restoring normalcy in grid in case of occurrence of sudden disturbances.