Scada And Power System Automation Pdf
File Name: scada and power system automation .zip
How new technologies can improve monitoring and control. Substations are a critical component for maintaining electrical supply and load control in low voltage, medium voltage and high voltage electrical distribution networks. In order to ensure the proper functioning of substations and related equipment such as line-mounted switches and capacitors, most utilities use SCADA supervisory control and data acquisition systems to automate monitoring and control.
- Scada And Power System Automation Pdf
- SCADA Systems for Electrical Distribution
- Application of SCADA for Controlling Electrical Power System Network
- Power-system automation
Table of Contents.
Power-system automation is the act of automatically controlling the power system via instrumentation and control devices. Substation automation refers to using data from Intelligent electronic devices IED , control and automation capabilities within the substation, and control commands from remote users to control power-system devices. Since full substation automation relies on substation integration, the terms are often used interchangeably. Power-system automation includes processes associated with generation and delivery of power.
Scada And Power System Automation Pdf
Those familiar with industrial instrumentation will find much within the electric power industry remarkably familiar in concept. Within each of those smaller processes in a large electrical power system there exist automatic monitoring and control systems very similar to industrial process controls.
A general block diagram showing the essential components of a feedback control system used elsewhere in this book applies to electrical power system automation as well:. Measurement devices in an electrical power system usually take the form of instrument transformers designed to represent high voltage and high current quantities as smaller, proportionate electrical signals. Controllers take the form of protective relays and other control systems designed to display and record the measured quantities, as well as take an automatic control action.
Modern electrical power automation systems, like industrial automation, also employ sophisticated digital communication subsystems to exchange critical data such as power flow and fault diagnosis across wide regions. Let us examine electric power substations as an example of automation. An example of a single-line diagram showing multiple substations appears here:.
Loads also appear as circles, but labeled uniquely. Circuit breakers used to interrupt the flow of power during full-load and fault conditions appear as squares, shown here with color-coded states. Disconnect switches used to isolate components from power during maintenance operations appear as standard schematic switch symbols: a line broken by a diagonal line segment.
Short line segments joining circuit breakers and disconnects with other devices in each station represent busses , which are sets of rigid metal conductors suspended by insulators. Longer lines connecting stations to each other represent transmission or distribution power lines. Transformers , used to step voltage up and current down for efficient long-distance transmission, or vice-versa for distribution and end-use, appear as standard schematic winding symbols.
This simplification is similar to the way road maps show streets and highways as single lines but generally do not show the number of lanes within each road. Within each of these substations you can see circuit breakers and disconnect switches used to route the flow of electricity from sources to loads.
These devices are analogous to control valves and block valves used to control fluid motion in industrial processes. These protective relays sense voltage and current conditions through instrument transformers stepping high voltage down to safe sensing levels Potential Transformers, or PTs and stepping line current down to safe levels Current Transformers, or CTs.
An example of a single-line diagram showing such an automated protection system for one of the power transformers in this system appears here:. Each protective relay function appears as a small circle enclosing a number, representing an industry-standardized code for that protective function e.
In this particular case, any condition of overcurrent or current imbalance for this transformer causes the lockout relay 86 to trip, which in turn commands both line and load circuit breakers to trip, isolating the power transformer and thereby protecting it from harm.
A single potential transformer array PT steps down the high line voltage to a safe level typically volts nominal for the wattmeter to read. A set of current transformers CTs step line current down to safe levels typically 5 amps at full load for the wattmeter and protective relays to read. As you can see, the disconnect switches have no connection to the automated system because they are manually-controlled devices, analogous to manual block valves flanking an automatic control valve in a process pipe.
Now that we know the functions of instrument transformers, protective relays, circuit breakers, and disconnect switches, we may examine some photographs of these power system components. First, we will examine some potential transformers PTs , sometimes referred to as voltage transformers VTs. The left-hand photograph shows a set of three PTs, each one used to sense phase-to-ground voltage in a kV 3-phase power bus within a substation. The right-hand photograph shows a single PT sensing phase-to-phase voltage i.
This is analogous to the industrial instrumentation signal standard of mA representing such things as pressure, flow, and temperature: a relatively small electrical signal is used as a representation of some other real-world measurement.
Next we will examine some current transformers CTs. The left-hand photograph shows a current transformer with a amp ratio, which means a line current of amps AC passing through the horizontal metal bar will induce a secondary winding current of 5 amps AC available at the screw terminals on top of this CT.
All of these CTs output a nominal current of 5 amps AC at full load rating, which is a common CT signal standard within the electrical power industry, like volts is for PT output signals. Together, PTs and CTs constitute the primary sensing elements of electrical power measurement, control, and protection systems. One of the tasks of metering and protection technicians in the electric power industry is to periodically check the accuracy and performance of these instrument transformers, just as an industrial instrument technician periodically checks the calibration of process sensing elements and transmitters.
Next we will examine some of the panel-mounted instruments receiving signals from PTs and CTs. First are simple meters, designed to display system measurements to human operators.
These instruments are labeled with high ranges despite the fact that their actual driving signals are relatively small e. This provides operators with remote viewing of device status, which is then displayed as different colors red or green on a graphic single-line diagram of the power system.
The scale of this particular display is such that individual circuit breakers are not represented, showing entire substations as single colored squares. However, more detailed diagrams are viewable by selecting a particular substation on this screen, these detailed displays showing individual circuit breakers and other associated equipment within that substation:. These automatic control devices have existed in one form or another for over a century, beginning with crude electromechanical designs and now culminating in state-of-the-art microprocessor-based computing machines.
Relay functions are commonly designated by numerical codes standardized by ANSI , some of which will be listed in this section. A series of electromechanical protective relays appears in the following photographs, taken at a large substation. The middle photograph shows a set of transformer differential current relays ANSI code 87 designed to compare the amount of current in the primary and secondary windings of a transformer, tripping circuit breakers on both sides of the transformer in the event a transformer fault is detected i.
The right-hand photograph shows a set of overpressure relays ANSI code 63 designed to trip circuit breakers feeding power to a device if the pressure inside that device rises to unacceptable levels:. A routine task for relay technicians working on electromechanical relays is periodic recalibration of these devices.
Since they contain potentiometers, magnets, inductive coils, and moving parts they are susceptible to calibration drift just like any other analog electronic or mechanical device. Modern digital electronic protective relays are also panel-mounted, but of course contain no moving parts and are much more capable in terms of their ability to discriminate between normal operating conditions and faulted conditions meriting the tripping of circuit breakers.
The following photographs show some examples of these devices. The left-hand photograph shows a transformer protection relay, incorporating the differential current ANSI code 87 protection of the previous electromechanical relay plus a number of other features including instantaneous and time-overcurrent functions.
The right-hand photograph shows a pair of digital relays, the upper one providing instantaneous overcurrent ANSI code 50 plus time-overcurrent ANSI code 51 plus circuit breaker reclosing ANSI code 79 functionality, tripping the circuit breaker in the event of excessive current, and then re-closing that same circuit breaker a short moment after to check if the fault has cleared.
One of the benefits of digital protective relays is their remarkable stability compared to electromechanical relays, being virtually immune to calibration drift. This translates to less routine maintenance for relay technicians.
Not only do modern protective relays perform their basic system protection functions, but they also record data for later retrieval and analysis by relay technicians and protection engineers. These relays, being microprocessor based, may also be interconnected using high-speed data networks to exchange data with each other as part of certain protection strategies. These new capabilities, coupled with the need to maintain accurate archives of digital relay configuration files, means the job of the relay technician has evolved: there is less routine calibration work, but more routine record-keeping and high-level diagnostic work.
Finally, we have the final control elements of the electric power industry: circuit breakers and disconnects. These two types of devices are common in that they both serve to connect and disconnect portions of a power system. They differ in their ability to interrupt current: circuit breakers are built with very rugged electrical contacts capable of safely and reliably interrupting huge magnitudes of electric current including currents arising from short-circuit faults in the power system , whereas disconnects are switches that cannot make or break such large currents, and are intended to be operated only when the series-connected circuit breaker is open tripped.
The following photographs show sets of three-phase kV disconnects, the left-hand photograph showing a set in the closed position and the right-hand photograph showing a set in the open position:. As you can see, a high-voltage disconnect is nothing more than an open-air knife switch. Some are manually operated by a lever or a hand crank while others use an electric motor for remote operation by a SCADA system or by an operator in a substation control room.
Medium-voltage and high-voltage circuit breakers come in a variety of shapes and sizes. Perhaps the most significant difference between them is the method s employed to extinguish the electric arc formed when the contacts separate to interrupt line current. The photograph on the left shows a legacy oil-tank circuit breaker in a kV substation yard, consisting of three separate tanks containing contacts to interrupt one phase each.
All three contacts operate simultaneously by the same mechanism. Safe and effective interruption of electric current at these elevated potentials demands quick contact action, and this is possible only with some form of stored-energy mechanism inside the circuit breaker. Some large circuit breakers use reservoirs filled with compressed air as the actuating medium, the reservoir maintained in a state of high pressure by an electric air compressor.
Other circuit breakers use mechanical springs pre-charged by an electric motor and gear mechanism. This volt battery bank is maintained in a continuous state of charge by an AC-DC battery charger fed from the AC power source not shown.
In summary, electric power systems employ automation to measure power conditions and take protective action when needed in the event of major line or device faults. These automated systems resemble industrial process control and safety systems in their three-part division sensing, control, and final action as well as in their graphical representation, calibration, and other maintenance.
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III - Measurement Vol. IV - Control Vol. V - Reference Worksheets. Textbook Introduction to Power System Automation. A general block diagram showing the essential components of a feedback control system used elsewhere in this book applies to electrical power system automation as well: Measurement devices in an electrical power system usually take the form of instrument transformers designed to represent high voltage and high current quantities as smaller, proportionate electrical signals.
An example of a single-line diagram showing such an automated protection system for one of the power transformers in this system appears here: Each protective relay function appears as a small circle enclosing a number, representing an industry-standardized code for that protective function e.
The right-hand photograph shows a set of overpressure relays ANSI code 63 designed to trip circuit breakers feeding power to a device if the pressure inside that device rises to unacceptable levels: A routine task for relay technicians working on electromechanical relays is periodic recalibration of these devices. The following photographs show sets of three-phase kV disconnects, the left-hand photograph showing a set in the closed position and the right-hand photograph showing a set in the open position: As you can see, a high-voltage disconnect is nothing more than an open-air knife switch.
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SCADA Systems for Electrical Distribution
EcoStruxure Power Automation System EPAS helps monitor, operate, and maintain these electrical systems with future-proof technologies like IEC , which revolutionizes the way we digitize, design, configure, and maintain the power grid, and IEC , the cybersecurity standard that supports security-by-design practices. It efficiently retrofits aging installations, helping to increase power reliability and energy efficiency capabilities. Scalable and interoperable, EPAS contributes to a more connected, digital, and efficient power system. EcoStruxure Power Automation System increases power reliability and optimizes maintenance routines of electrical processes thanks to a wide range of supported communication protocols and the ability to communicate them to cloud-based applications that constantly monitor asset conditions such as temperature and vibration. Real-time automation schemes based on the IEC standard over interoperable IEC communication services help provide smarter solutions for power distribution systems in electro-intensive and electro-sensitive industries. Power Management System.
Application of SCADA for Controlling Electrical Power System Network
Senior Consultant: to PresentDeveloped product plans, conceptual and preliminary designs for projects, performed industry surveys and developed You need to be a member of Energy Central to access some features and content. Please sign-in or register to continue. As I mentioned in the first part of this series, I have spent many of my past years working in SCADA technology, and this ultimately led me to a present and future technology: Microgrids.
Supervisory control and data acquisition SCADA is a control system architecture comprising computers , networked data communications and graphical user interfaces GUI for high-level process supervisory management, while also comprising other peripheral devices like programmable logic controllers PLC and discrete proportional-integral-derivative PID controllers to interface with process plant or machinery. The use of SCADA has been considered also for management and operations of project-driven-process in construction. The operator interfaces which enable monitoring and the issuing of process commands, like controller set point changes, are handled through the SCADA computer system. The subordinated operations, e. The SCADA concept was developed to be a universal means of remote-access to a variety of local control modules, which could be from different manufacturers and allowing access through standard automation protocols. In practice, large SCADA systems have grown to become very similar to distributed control systems in function, while using multiple means of interfacing with the plant. They can control large-scale processes that can include multiple sites, and work over large distances as well as small distance.
automatic control system, being used in distribution. automation for quality power. The Scada Systems Remote Terminal Unit (RTU). will be installed in SUB.
Scada And Power System Automation Pdf: Solutions For Power And Automation Integration
Power System Automation server should transfer all the alarm generated to the Facility Management server. Thin Client Operator Workstation The SCADA system operator shall be able to execute all monitoring and supervisory control functions from a thin client workstation or environment. It consists of one or more computers with appropriate applications software Master Stations connected by communications system wire, radio, power line carrier or fiberFile Size: KB. SCADA systems in a way that is consistent with the operation and mission of that system. SCADA system is one of the most important legacy systems of the smart grid systems. There are four conditions for PLC simulation tests to.
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Правду знала только элита АНБ - ТРАНСТЕКСТ взламывал сотни шифров ежедневно. В условиях, когда пользователи были убеждены, что закодированные с помощью компьютера сообщения не поддаются расшифровке - даже усилиями всемогущего АНБ, - секреты потекли рекой. Наркобароны, боссы, террористы и люди, занятые отмыванием криминальных денег, которым надоели перехваты и прослушивание их переговоров по сотовым телефонам, обратились к новейшему средству мгновенной передачи сообщений по всему миру - электронной почте. Теперь, считали они, им уже нечего было опасаться, представ перед Большим жюри, услышать собственный записанный на пленку голос как доказательство давно забытого телефонного разговора, перехваченного спутником АНБ. Никогда еще получение разведывательной информации не было столь легким делом. Шифры, перехваченные АНБ, вводились в ТРАНСТЕКСТ и через несколько минуты выплевывались из машины в виде открытого текста.
Беккер прижал дуло к виску убийцы и осторожно наклонился.
ГЛАВА 29 Все еще нервничая из-за столкновения с Хейлом, Сьюзан вглядывалась в стеклянную стену Третьего узла. В шифровалке не было ни души. Хейл замолк, уставившись в свой компьютер.
Там подают отличный карпаччо. - Хейл улыбнулся. - Что скажешь. А потом мы могли бы… - Выкинь это из головы. - Сколько в тебе снобизма.