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122-458: Substations may be owned and operated by an electrical utility, or may be owned by a large industrial or commercial customer. Generally substations are unattended, relying on SCADA for remote supervision and control. The word substation comes from the days before the distribution system became a grid . As central generation stations became larger, smaller generating plants were converted to distribution stations, receiving their energy supply from

244-447: A bus plus some circuit breakers . The largest transmission substations can cover a large area (several acres/hectares) with multiple voltage levels, many circuit breakers, and a large amount of protection and control equipment ( voltage and current transformers , relays and SCADA systems). Modern substations may be implemented using international standards such as IEC Standard 61850 . A distribution substation transfers power from

366-567: A tag database , which contains data elements called tags or points , which relate to specific instrumentation or actuators within the process system. Data is accumulated against these unique process control equipment tag references. A SCADA system usually consists of the following main elements: An important part of most SCADA implementations is alarm handling . The system monitors whether certain alarm conditions are satisfied, to determine when an alarm event has occurred. Once an alarm event has been detected, one or more actions are taken (such as

488-482: A LAN. Information was shared in near real time. Each station was responsible for a particular task, which reduced the cost as compared to First Generation SCADA. The network protocols used were still not standardized. Since these protocols were proprietary, very few people beyond the developers knew enough to determine how secure a SCADA installation was. Security of the SCADA installation was usually overlooked. Similar to

610-455: A SCADA device by sending commands over a network. In many cases SCADA users have assumed that having a VPN offered sufficient protection, unaware that security can be trivially bypassed with physical access to SCADA-related network jacks and switches. Industrial control vendors suggest approaching SCADA security like Information Security with a defense in depth strategy that leverages common IT practices. Apart from that, research has shown that

732-402: A blade length up to 80 meters (260 ft). Designs with 10 to 12 MW were in preparation in 2018, and a "15 MW+" prototype with three 118-metre (387 ft) blades is planned to be constructed in 2022. The average hub height of horizontal axis wind turbines is 90 meters. Vertical-axis wind turbines (or VAWTs) have the main rotor shaft arranged vertically. One advantage of this arrangement

854-410: A contractor for actual construction. Major design constraints for construction of substations include land availability and cost, limitations on the construction period, transportation restrictions, and the need to get the substation running quickly. Prefabrication is a common way to reduce the construction cost. For connecting the new substation, a partial outage at another substation may be required, but

976-482: A contractor installed a SCADA system in January 2000, system components began to function erratically. Pumps did not run when needed and alarms were not reported. More critically, sewage flooded a nearby park and contaminated an open surface-water drainage ditch and flowed 500 meters to a tidal canal. The SCADA system was directing sewage valves to open when the design protocol should have kept them closed. Initially this

1098-706: A disconnection of the load supplied by the circuit break from the feeding point. This seeks to isolate the fault point from the rest of the system, and allow the rest of the system to continue operating with minimal impact. Both switches and circuit breakers may be operated locally (within the substation) or remotely from a supervisory control center. With overhead transmission lines , the propagation of lightning and switching surges can cause insulation failures into substation equipment. Line entrance surge arrestors are used to protect substation equipment accordingly. Insulation Coordination studies are carried out extensively to ensure equipment failure (and associated outages )

1220-419: A distributed architecture, any complex SCADA can be reduced to the simplest components and connected through communication protocols. In the case of a networked design, the system may be spread across more than one LAN network called a process control network (PCN) and separated geographically. Several distributed architecture SCADAs running in parallel, with a single supervisor and historian, could be considered

1342-441: A gearbox, which turns the slow rotation of the blades into a quicker rotation that is more suitable to drive an electrical generator. Some turbines use a different type of generator suited to slower rotational speed input. These don't need a gearbox and are called direct-drive, meaning they couple the rotor directly to the generator with no gearbox in between. While permanent magnet direct-drive generators can be more costly due to

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1464-412: A greater friction moment and thus a lower power coefficient. The air velocity is the major contributor to the turbine efficiency. This is the reason for the importance of choosing the right location. The wind velocity will be high near the shore because of the temperature difference between the land and the ocean. Another option is to place turbines on mountain ridges. The higher the wind turbine will be,

1586-457: A large substation, circuit breakers are used to interrupt any short circuits or overload currents that may occur on the network. Smaller distribution stations may use recloser circuit breakers or fuses for protection of distribution circuits. Substations themselves do not usually have generators, although a power plant may have a substation nearby. Other devices such as capacitors , voltage regulators , and reactors may also be located at

1708-422: A larger plant instead of using their own generators. The first substations were connected to only one power station , where the generators were housed, and were subsidiaries of that power station. Substations may be designed and built by a contractor or alternately all phases of its development may be handled by the electrical utility . Most commonly, the utility does the engineering and procurement while hiring

1830-521: A long lease such as a renewable 99-year lease, giving the utility company security of tenure . The first step in planning a substation layout is the preparation of a one-line diagram , which shows in simplified form the switching and protection arrangement required, as well as the incoming supply lines and outgoing feeders or transmission lines. It is a usual practice by many electrical utilities to prepare one-line diagrams with principal elements (lines, switches, circuit breakers, transformers) arranged on

1952-474: A lower blade speed ratio, which lowers blade bending stresses. Straight, V, or curved blades may be used. These are drag-type devices with two (or more) scoops that are used in anemometers, Flettner vents (commonly seen on bus and van roofs), and in some high-reliability low-efficiency power turbines. They are always self-starting if there are at least three scoops. Twisted Savonius is a modified savonius, with long helical scoops to provide smooth torque. This

2074-447: A modern SCADA system. One is the threat of unauthorized access to the control software, whether it is human access or changes induced intentionally or accidentally by virus infections and other software threats residing on the control host machine. Another is the threat of packet access to the network segments hosting SCADA devices. In many cases, the control protocol lacks any form of cryptographic security , allowing an attacker to control

2196-460: A network architecture. This allows for a more cost-effective solution in very large scale systems. The growth of the internet has led SCADA systems to implement web technologies allowing users to view data, exchange information and control processes from anywhere in the world through web SOCKET connection. The early 2000s saw the proliferation of Web SCADA systems. Web SCADA systems use internet browsers such as Google Chrome and Mozilla Firefox as

2318-686: A ring bus, double bus, or so-called "breaker and a half" setup can be used, so that the failure of any one circuit breaker does not interrupt power to other circuits, and so that parts of the substation may be de-energized for maintenance and repairs. Substations feeding only a single industrial load may have minimal switching provisions, especially for small installations. Because of the risk of electrical shock, substations are inherently dangerous to electrical workers. To mitigate this hazard, substations are designed with various safety features. Live conductors and bare equipment are kept separate, either with protected equipment, or using screens or distance. Based on

2440-473: A screen (that might act in a similar way to the "fuel tank empty" light in a car); in each case, the role of the alarm indicator is to draw the operator's attention to the part of the system 'in alarm' so that appropriate action can be taken. "Smart" RTUs, or standard PLCs, are capable of autonomously executing simple logic processes without involving the supervisory computer. They employ standardized control programming languages (such as those under IEC 61131-3 ,

2562-584: A series of batteries . The batteries powered various electrical tools and lamps, as well as a threshing machine. Friedländer's windmill and its accessories were prominently installed at the north entrance to the main exhibition hall (" Rotunde ") in the Vienna Prater . In July 1887, Scottish academic James Blyth installed a battery-charging machine to light his holiday home in Marykirk , Scotland. Some months later, American inventor Charles F. Brush

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2684-417: A stable environment. Different materials have varying effects on the efficiency of wind turbines. In an Ege University experiment, three wind turbines, each with three blades with a diameter of one meter, were constructed with blades made of different materials: A glass and glass/carbon epoxy , glass/carbon, and glass/polyester. When tested, the results showed that the materials with higher overall masses had

2806-511: A standard attack type leveraging access to the Tomcat Embedded Web server . Security researcher Jerry Brown submitted a similar advisory regarding a buffer overflow vulnerability in a Wonderware InBatchClient ActiveX control . Both vendors made updates available prior to public vulnerability release. Mitigation recommendations were standard patching practices and requiring VPN access for secure connectivity. Consequently,

2928-678: A substation. Substations may be on the surface in fenced enclosures, underground, or special-purpose buildings. High-rise buildings may have several indoor substations. Indoor substations are usually found in urban areas to reduce the noise from transformers, improve appearance, or protect switchgear from extreme climate or pollution. Substations often use busbars as conductors between electrical equipment. Busbars may be aluminum tubing 3–6 inches (76–152 mm) thick, or else wires (strain bus). Outdoor, above-ground substation structures include wood pole, lattice metal tower, and tubular metal structures, although other variants are available. Where space

3050-422: A suite of five programming languages including function block, ladder, structured text, sequence function charts and instruction list), that are frequently used to create programs which run on these RTUs and PLCs. Unlike a procedural language like C or FORTRAN , IEC 61131-3 has minimal training requirements by virtue of resembling historic physical control arrays. This allows SCADA system engineers to perform both

3172-422: A transmission line or a transformer. To maintain reliability of supply, companies aim at keeping the system up and running while performing maintenance. All work to be performed, from routine testing to adding entirely new substations, should be done while keeping the whole system running. Unplanned switching events are caused by a fault in a transmission line or any other component, for example: The function of

3294-445: A working group, WG4. WG4 "deals specifically with unique technical requirements, measurements, and other features required to evaluate and assure security resilience and performance of industrial automation and control systems devices". The increased interest in SCADA vulnerabilities has resulted in vulnerability researchers discovering vulnerabilities in commercial SCADA software and more general offensive SCADA techniques presented to

3416-429: Is a digital status point that has either the value NORMAL or ALARM that is calculated by a formula based on the values in other analogue and digital points—or implicit: the SCADA system might automatically monitor whether the value in an analogue point lies outside high and low- limit values associated with that point. Examples of alarm indicators include a siren, a pop-up box on a screen, or a coloured or flashing area on

3538-419: Is a major drawback. Vertical turbine designs have much lower efficiency than standard horizontal designs. The key disadvantages include the relatively low rotational speed with the consequential higher torque and hence higher cost of the drive train, the inherently lower power coefficient , the 360-degree rotation of the aerofoil within the wind flow during each cycle and hence the highly dynamic loading on

3660-599: Is aimed at minimizing cost while ensuring power availability and reliability, and enabling changes to the substation in the future. Substations may be built outdoors, indoors, or underground or in a combination of these locations. Selection of the location of a substation must consider many factors. Sufficient land area is required for installation of equipment with necessary clearances for electrical safety, and for access to maintain large apparatus such as transformers. The site must have room for expansion due to load growth or planned transmission additions. Environmental effects of

3782-474: Is also frequently used for large systems such as railways and power stations. The remote management or monitoring function of a SCADA system is often referred to as telemetry . Some users want SCADA data to travel over their pre-established corporate networks or to share the network with other applications. The legacy of the early low-bandwidth protocols remains, though. SCADA protocols are designed to be very compact. Many are designed to send information only when

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3904-431: Is approximately 50% of the building height it is near the optimum for maximum wind energy and minimum wind turbulence. While wind speeds within the built environment are generally much lower than at exposed rural sites, noise may be a concern and an existing structure may not adequately resist the additional stress. Subtypes of the vertical axis design include: "Eggbeater" turbines, or Darrieus turbines, were named after

4026-465: Is common in the area. The output is a number of feeders. Distribution voltages are typically medium voltage, between 2.4 kV and 33 kV, depending on the size of the area served and the practices of the local utility. The feeders run along streets overhead (or underground, in some cases) and power the distribution transformers at or near the customer premises. In addition to transforming voltage, distribution substations also isolate faults in either

4148-663: Is compiled here. An example of efforts by vendor groups to standardize automation protocols is the OPC-UA (formerly "OLE for process control" now Open Platform Communications Unified Architecture ). SCADA systems have evolved through four generations as follows: Early SCADA system computing was done by large minicomputers . Common network services did not exist at the time SCADA was developed. Thus SCADA systems were independent systems with no connectivity to other systems. The communication protocols used were strictly proprietary at that time. The first-generation SCADA system redundancy

4270-623: Is determined by the stiffness of fibers and their volume content. Typically, E-glass fibers are used as main reinforcement in the composites. Typically, the glass/epoxy composites for wind turbine blades contain up to 75% glass by weight. This increases the stiffness, tensile and compression strength. A promising composite material is glass fiber with modified compositions like S-glass, R-glass etc. Other glass fibers developed by Owens Corning are ECRGLAS, Advantex and WindStrand. Carbon fiber has more tensile strength, higher stiffness and lower density than glass fiber. An ideal candidate for these properties

4392-402: Is minimal. Once past the switching components, the lines of a given voltage connect to one or more buses . These are sets of busbars , usually in multiples of three, since three-phase electrical power distribution is largely universal around the world. The arrangement of switches, circuit breakers, and buses used affects the cost and reliability of the substation. For important substations

4514-470: Is necessary to work on parts of the substation while energized, but employees must maintain a safe distance of at least 3 metres (9.8 ft). The aim to reduce substation footprints comes into conflict with ease of maintenance enhanced by including gaps where employees can safely work. Underneath a substation, a mat or grid of conductors laid around 0.5 or 0.6 metres (1 ft 8 in or 2 ft 0 in) underground provides grounding . This grid, which

4636-574: Is often used as a rooftop wind turbine and has even been adapted for ships . Airborne wind turbines consist of wings or a small aircraft tethered to the ground. They are useful for reaching faster winds above which traditional turbines can operate. There are prototypes in operation in east Africa. These are offshore wind turbines that are supported by a floating platform. By having them float, they are able to be installed in deeper water allowing more of them. This also allows them to be further out of sight from land and therefore less public concern about

4758-472: Is plentiful and appearance of the station is not a factor, steel lattice towers provide low-cost supports for transmission lines and apparatus. Low-profile substations may be specified in suburban areas where appearance is more critical. Indoor substations may be gas insulated substations (GIS) (at high voltages, with gas insulated switchgear), or use metal-enclosed or metal-clad switchgear at lower voltages. Urban and suburban indoor substations may be finished on

4880-520: Is that the turbine does not need to be pointed into the wind to be effective, which is an advantage on a site where the wind direction is highly variable. It is also an advantage when the turbine is integrated into a building because it is inherently less steerable. Also, the generator and gearbox can be placed near the ground, using a direct drive from the rotor assembly to the ground-based gearbox, improving accessibility for maintenance. However, these designs produce much less energy averaged over time, which

5002-448: Is the spar cap, a structural element of a blade that experiences high tensile loading. A 100-metre (330 ft) glass fiber blade could weigh up to 50 tonnes (110,000 lb), while using carbon fiber in the spar saves 20% to 30% weight, about 15 tonnes (33,000 lb). Instead of making wind turbine blade reinforcements from pure glass or pure carbon, hybrid designs trade weight for cost. For example, for an 8-metre (26 ft) blade,

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5124-448: Is typically copper although it may be galvanized iron in some countries, is used to ground circuits that are being worked on to prevent accidental re-energization while workers are in contact with a de-energized circuit. Often, earth rods are driven deeper into the ground from the grounding grid for lower resistance grounding, and may be surrounded by bentonite or marconite to further reduce resistance and ensure effective grounding for

5246-410: Is used as a protection device to interrupt fault currents automatically, and may be used to switch loads on and off, or to cut off a line when power is flowing in the 'wrong' direction. When a large fault current flows through the circuit breaker, this is detected through the use of current transformers . The magnitude of the current transformer outputs may be used to trip the circuit breaker resulting in

5368-416: The microprocessor made for an exponential increase in the number of points that could be economically controlled and monitored. Today, standardized communication protocols such as DNP3 , IEC 61850 and Modbus , to list a few, are used to allow multiple intelligent electronic devices to communicate with each other and supervisory control centers. Distributed automatic control at substations is one element of

5490-428: The "lowest relative greenhouse gas emissions, the least water consumption demands and the most favorable social impacts" compared to photovoltaic , hydro , geothermal , coal and gas energy sources. Smaller wind turbines are used for applications such as battery charging and remote devices such as traffic warning signs. Larger turbines can contribute to a domestic power supply while selling unused power back to

5612-501: The 11th and 12th centuries; there are reports of German crusaders taking their windmill-making skills to Syria around 1190. By the 14th century, Dutch windmills were in use to drain areas of the Rhine delta. Advanced wind turbines were described by Croatian inventor Fausto Veranzio in his book Machinae Novae (1595). He described vertical axis wind turbines with curved or V-shaped blades. The first electricity-generating wind turbine

5734-617: The 7th century. These " Panemone " were vertical axle windmills, which had long vertical drive shafts with rectangular blades. Made of six to twelve sails covered in reed matting or cloth material, these windmills were used to grind grain or draw up water, and were used in the gristmilling and sugarcane industries. Wind power first appeared in Europe during the Middle Ages . The first historical records of their use in England date to

5856-521: The Betz limit of power extractable from the wind, at rated operating speed. Efficiency can decrease slightly over time, one of the main reasons being dust and insect carcasses on the blades, which alter the aerodynamic profile and essentially reduce the lift to drag ratio of the airfoil . Analysis of 3128 wind turbines older than 10 years in Denmark showed that half of the turbines had no decrease, while

5978-465: The Czech Republic, where power is collected from nearby lignite -fired power plants. If no transformers are required for increasing the voltage to transmission level, the substation is a switching station. Converter substations may be associated with HVDC converter plants, traction current , or interconnected non-synchronous networks. These stations contain power electronic devices to change

6100-470: The French inventor, Georges Darrieus. They have good efficiency, but produce large torque ripple and cyclical stress on the tower, which contributes to poor reliability. They also generally require some external power source, or an additional Savonius rotor to start turning, because the starting torque is very low. The torque ripple is reduced by using three or more blades, which results in greater solidity of

6222-741: The Nation’s critical infrastructures represent a systemic threat to their continued operation following an EMP event. Additionally, the necessity to reboot, repair, or replace large numbers of geographically widely dispersed systems will considerably impede the Nation’s recovery from such an assault." Many vendors of SCADA and control products have begun to address the risks posed by unauthorized access by developing lines of specialized industrial firewall and VPN solutions for TCP/IP-based SCADA networks as well as external SCADA monitoring and recording equipment. The International Society of Automation (ISA) started formalizing SCADA security requirements in 2007 with

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6344-461: The SCADA master in lieu of a traditional RTU. Since about 1998, virtually all major PLC manufacturers have offered integrated HMI/SCADA systems, many of them using open and non-proprietary communications protocols. Numerous specialized third-party HMI/SCADA packages, offering built-in compatibility with most major PLCs, have also entered the market, allowing mechanical engineers, electrical engineers and technicians to configure HMIs themselves, without

6466-478: The SCADA to readings and equipment status reports that are communicated to level 2 SCADA as required. Data is then compiled and formatted in such a way that a control room operator using the human-machine interface (HMI) can make supervisory decisions to adjust or override normal RTU (PLC) controls. Data may also be fed to a historian , often built on a commodity database management system , to allow trending and other analytical auditing. SCADA systems typically use

6588-467: The US), there is increasing use of satellite-based communication. This has the key advantages that the infrastructure can be self-contained (not using circuits from the public telephone system), can have built-in encryption, and can be engineered to the availability and reliability required by the SCADA system operator. Earlier experiences using consumer-grade VSAT were poor. Modern carrier-class systems provide

6710-477: The United States from 5 kilowatts (kW) to 25 kW. Around the time of World War I, American windmill makers were producing 100,000 farm windmills each year, mostly for water-pumping. By the 1930s, use of wind turbines in rural areas was declining as the distribution system extended to those areas. A forerunner of modern horizontal-axis wind generators was in service at Yalta , USSR, in 1931. This

6832-418: The activation of one or more alarm indicators, and perhaps the generation of email or text messages so that management or remote SCADA operators are informed). In many cases, a SCADA operator may have to acknowledge the alarm event; this may deactivate some alarm indicators, whereas other indicators remain active until the alarm conditions are cleared. Alarm conditions can be explicit—for example, an alarm point

6954-443: The air arrives at the turbine. The maximum theoretical power output of a wind machine is thus 16 ⁄ 27 times the rate at which kinetic energy of the air arrives at the effective disk area of the machine. If the effective area of the disk is A, and the wind velocity v, the maximum theoretical power output P is: where ρ is the air density . Wind-to-rotor efficiency (including rotor blade friction and drag ) are among

7076-589: The amps exceed a certain amount over a period of time. Reclosers will attempt to re-energize the circuit after a delay. If unsuccessful for a few times, the recloser will have to be manually reset by an electrical worker. Capacitor banks are used in substations to balance the lagging current draw from inductive loads (such as motors, transformers, and some industrial equipment) with their reactive load . Additional capacitor capacity may be needed if dispersed generation (such as small diesel generators, rooftop photovoltaic solar panels , or wind turbines ) are added to

7198-746: The architecture of SCADA systems has several other vulnerabilities, including direct tampering with RTUs, communication links from RTUs to the control center, and IT software and databases in the control center. The RTUs could, for instance, be targets of deception attacks injecting false data or denial-of-service attacks . The reliable function of SCADA systems in our modern infrastructure may be crucial to public health and safety. As such, attacks on these systems may directly or indirectly threaten public health and safety. Such an attack has already occurred, carried out on Maroochy Shire Council's sewage control system in Queensland , Australia . Shortly after

7320-491: The basis of modern society. The security of these SCADA systems is important because compromise or destruction of these systems would impact multiple areas of society far removed from the original compromise. For example, a blackout caused by a compromised electrical SCADA system would cause financial losses to all the customers that received electricity from that source. How security will affect legacy SCADA and new deployments remains to be seen. There are many threat vectors to

7442-430: The blade, the pulsating torque generated by some rotor designs on the drive train, and the difficulty of modelling the wind flow accurately and hence the challenges of analysing and designing the rotor prior to fabricating a prototype. When a turbine is mounted on a rooftop the building generally redirects wind over the roof and this can double the wind speed at the turbine. If the height of a rooftop mounted turbine tower

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7564-580: The blades snapped off. The unit was not repaired, because of a shortage of materials during the war. The first utility grid-connected wind turbine to operate in the UK was built by John Brown & Company in 1951 in the Orkney Islands . In the early 1970s, however, anti-nuclear protests in Denmark spurred artisan mechanics to develop microturbines of 22 kW despite declines in the industry. Organizing owners into associations and co-operatives led to

7686-414: The blades upwind of the tower ( i.e.   blades facing the incoming wind) produce the overwhelming majority of wind power in the world today. These turbines have the main rotor shaft and electrical generator at the top of a tower and must be pointed into the wind. Small turbines are pointed by a simple wind vane , while large turbines generally use a wind sensor coupled with a yaw system. Most have

7808-587: The complexity of distribution networks grew, it became economically necessary to automate supervision and control of substations from a centrally attended point, to allow overall coordination in case of emergencies and to reduce operating costs. Early efforts to remote control substations used dedicated communication wires, often run alongside power circuits. Power-line carrier , microwave radio , fiber optic cables as well as dedicated wired remote control circuits have all been applied to Supervisory Control and Data Acquisition (SCADA) for substations. The development of

7930-477: The current to back-up lines or for parallelizing circuits in case of failure. An example is the switching stations for the HVDC Inga–Shaba transmission line. A switching station may also be known as a switchyard, and these are commonly located directly adjacent to or nearby a power station . In this case the generators from the power station supply their power into the yard onto the generator bus on one side of

8052-536: The design and implementation of a program to be executed on an RTU or PLC. A programmable automation controller (PAC) is a compact controller that combines the features and capabilities of a PC-based control system with that of a typical PLC. PACs are deployed in SCADA systems to provide RTU and PLC functions. In many electrical substation SCADA applications, "distributed RTUs" use information processors or station computers to communicate with digital protective relays , PACs, and other devices for I/O, and communicate with

8174-414: The energy converted to electrical energy. Since outgoing wind will still possess some kinetic energy, there must be a maximum proportion of the input energy that is available to be converted to electrical energy. Accordingly, Betz's law gives the maximal achievable extraction of wind power by a wind turbine, known as Betz's coefficient, as 16 ⁄ 27 (59.3%) of the rate at which the kinetic energy of

8296-416: The equipment used to monitor, control, and protect the rest of the substation equipment. It often contains protective relays, meters, breaker controls, communications, batteries, and recorders that save detailed data about substation operations, particularly when there is any unusual activity, to help reconstruct what happened after the fact. These control rooms typically are heated and air conditioned to ensure

8418-453: The factors affecting the final price of wind power. Further inefficiencies, such as gearbox , generator, and converter losses, reduce the power delivered by a wind turbine. To protect components from undue wear, extracted power is held constant above the rated operating speed as theoretical power increases as the cube of wind speed, further reducing theoretical efficiency. In 2001, commercial utility-connected turbines delivered 75% to 80% of

8540-422: The first detection of malware that attacks SCADA systems (Siemens' WinCC /PCS 7 systems) running on Windows operating systems. The malware is called Stuxnet and uses four zero-day attacks to install a rootkit which in turn logs into the SCADA's database and steals design and control files. The malware is also capable of changing the control system and hiding those changes. The malware was found on 14 systems,

8662-425: The frequency of current, or else convert from alternating to direct current or the reverse. Formerly rotary converters changed frequency to interconnect two systems; nowadays such substations are rare. A switching station is a substation without transformers and operating only at a single voltage level. Switching stations are sometimes used as collector and distribution stations. Sometimes they are used for switching

8784-422: The general security community. In electric and gas utility SCADA systems, the vulnerability of the large installed base of wired and wireless serial communications links is addressed in some cases by applying bump-in-the-wire devices that employ authentication and Advanced Encryption Standard encryption rather than replacing all existing nodes. In June 2010, anti-virus security company VirusBlokAda reported

8906-998: The generator, is 15.24 meters (50.0 ft) and weighs around 300 tons. Due to data transmission problems, structural health monitoring of wind turbines is usually performed using several accelerometers and strain gages attached to the nacelle to monitor the gearbox and equipment. Currently, digital image correlation and stereophotogrammetry are used to measure dynamics of wind turbine blades. These methods usually measure displacement and strain to identify location of defects. Dynamic characteristics of non-rotating wind turbines have been measured using digital image correlation and photogrammetry. Three dimensional point tracking has also been used to measure rotating dynamics of wind turbines. Generally, efficiency increases along with turbine blade lengths. The blades must be stiff, strong, durable, light and resistant to fatigue. Materials with these properties include composites such as polyester and epoxy, while glass fiber and carbon fiber have been used for

9028-597: The graphical user interface (GUI) for the operators HMI. This simplifies the client side installation and enables users to access the system from various platforms with web browsers such as servers, personal computers, laptops, tablets and mobile phones. SCADA systems that tie together decentralized facilities such as power, oil, gas pipelines, water distribution and wastewater collection systems were designed to be open, robust, and easily operated and repaired, but not necessarily secure. The move from proprietary technologies to more standardized and open solutions together with

9150-411: The higher the wind velocity on average. A windbreak can also increase the wind velocity near the turbine. Wind turbines can rotate about either a horizontal or a vertical axis, the former being both older and more common. They can also include blades or be bladeless. Household-size vertical designs produce less power and are less common. Large three-bladed horizontal-axis wind turbines (HAWT) with

9272-540: The increased number of connections between SCADA systems, office networks and the Internet has made them more vulnerable to types of network attacks that are relatively common in computer security . For example, United States Computer Emergency Readiness Team (US-CERT) released a vulnerability advisory warning that unauthenticated users could download sensitive configuration information including password hashes from an Inductive Automation Ignition system utilizing

9394-667: The issuing of process commands, such as controller setpoint changes, are handled through the SCADA computer system. The subordinated operations, e.g. the real-time control logic or controller calculations, are performed by networked modules connected to the field sensors and actuators . 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 similar to distributed control systems in function, while using multiple means of interfacing with

9516-405: The jurisdiction or company, there are safety standards with minimum required clearance between different live equipment or conductors or between live metal and the ground, which often varies with higher clearance being required for higher voltages because of the greater ability to generate flashover . To this is added the necessary space for employees to work safely and vehicles to pass. Sometimes it

9638-586: The lifetime of the substation. Above ground, the grounding conductors may be steel, aluminum, or copper. They must be thick enough to carry the expected current of a fault for 1-3 seconds and remain undamaged. Substation fences, typically at least 2 metres (6 ft 7 in) in height, both protect the public from electrical hazards and also protect the substation from vandalism. Internal fences can also be incorporated to protect employees from areas that are unsafe when energized. Substations generally have switching, protection and control equipment, and transformers. In

9760-813: The lobbying of the government and utilities and provided incentives for larger turbines throughout the 1980s and later. Local activists in Germany, nascent turbine manufacturers in Spain, and large investors in the United States in the early 1990s then lobbied for policies that stimulated the industry in those countries. It has been argued that expanding the use of wind power will lead to increasing geopolitical competition over critical materials for wind turbines, such as rare earth elements neodymium , praseodymium , and dysprosium . However, this perspective has been critically dismissed for failing to relay how most wind turbines do not use permanent magnets and for underestimating

9882-411: The low-voltage side. More typical distribution substations have a switch, one transformer, and minimal facilities on the low-voltage side. In distributed generation projects such as a wind farm or photovoltaic power station , a collector substation may be required. It resembles a distribution substation although power flow is in the opposite direction, from many wind turbines or inverters up into

10004-625: The majority of which were located in Iran. In October 2013 National Geographic released a docudrama titled American Blackout which dealt with an imagined large-scale cyber attack on SCADA and the United States' electrical grid. Both large and small systems can be built using the SCADA concept. These systems can range from just tens to thousands of control loops , depending on the application. Example processes include industrial, infrastructure, and facility-based processes, as described below: However, SCADA systems may have security vulnerabilities, so

10126-588: The master station polls the RTU. Typical legacy SCADA protocols include Modbus RTU, RP-570 , Profibus and Conitel. These communication protocols, with the exception of Modbus (Modbus has been made open by Schneider Electric), are all SCADA-vendor specific but are widely adopted and used. Standard protocols are IEC 60870-5-101 or 104 , IEC 61850 and DNP3 . These communication protocols are standardized and recognized by all major SCADA vendors. Many of these protocols now contain extensions to operate over TCP/IP . Although

10248-430: The need for a custom-made program written by a software programmer. The Remote Terminal Unit (RTU) connects to physical equipment. Typically, an RTU converts the electrical signals from the equipment to digital values. By converting and sending these electrical signals out to equipment the RTU can control equipment. SCADA systems have traditionally used combinations of radio and direct wired connections, although SONET/SDH

10370-562: The other half saw a production decrease of 1.2% per year. In general, more stable and constant weather conditions (most notably wind speed) result in an average of 15% greater efficiency than that of a wind turbine in unstable weather conditions, thus allowing up to a 7% increase in wind speed under stable conditions. This is due to a faster recovery wake and greater flow entrainment that occur in conditions of higher atmospheric stability. However, wind turbine wakes have been found to recover faster under unstable atmospheric conditions as opposed to

10492-411: The outside so as to blend in with other buildings in the area. A compact substation is generally an outdoor substation built in a metal enclosure, in which each item of the electrical equipment is located very near to each other to create a relatively smaller footprint size of the substation. High-voltage circuit breakers are commonly used to interrupt the flow of current in substation equipment. At

10614-406: The page similarly to the way the apparatus would be laid out in the actual station. In a common design, incoming lines have a disconnect switch and a circuit breaker . In some cases, the lines will not have both, with either a switch or a circuit breaker being all that is considered necessary. A disconnect switch is used to provide isolation, since it cannot interrupt load current. A circuit breaker

10736-435: The plant. They can control large-scale processes that can span multiple sites, and work over large distances. It is one of the most commonly-used types of industrial control systems . The key attribute of a SCADA system is its ability to perform a supervisory operation over a variety of other proprietary devices. Level 1 contains the programmable logic controllers (PLCs) or remote terminal units (RTUs). Level 2 contains

10858-439: The power of economic incentives for the expanded production of these minerals. Wind Power Density (WPD) is a quantitative measure of wind energy available at any location. It is the mean annual power available per square meter of swept area of a turbine, and is calculated for different heights above ground. Calculation of wind power density includes the effect of wind velocity and air density. Wind turbines are classified by

10980-660: The public grid. Sometimes they are also transmission substations or collector substations if the railway network also operates its own grid and generators to supply the other stations. A mobile substation is a substation on wheels, containing a transformer, breakers and buswork mounted on a self-contained semi-trailer , meant to be pulled by a truck . They are designed to be compact for travel on public roads, and are used for temporary backup in times of natural disaster or war . Mobile substations are usually rated much lower than permanent installations, and may be built in several units to meet road travel limitations. Substation design

11102-414: The quality of service required for SCADA. RTUs and other automatic controller devices were developed before the advent of industry wide standards for interoperability. The result is that developers and their management created a multitude of control protocols. Among the larger vendors, there was also the incentive to create their own protocol to "lock in" their customer base. A list of automation protocols

11224-469: The rare earth materials required, these gearless turbines are sometimes preferred over gearbox generators because they "eliminate the gear-speed increaser, which is susceptible to significant accumulated fatigue torque loading, related reliability issues, and maintenance costs". There is also the pseudo direct drive mechanism, which has some advantages over the permanent magnet direct drive mechanism. Most horizontal axis turbines have their rotors upwind of

11346-435: The reinforcing. Construction may involve manual layup or injection molding. Retrofitting existing turbines with larger blades reduces the task and risks of redesign. As of 2021, the longest blade was 115.5 m (379 ft), producing 15 MW. Blades usually last around 20 years, the typical lifespan of a wind turbine. Materials commonly used in wind turbine blades are described below. The stiffness of composites

11468-409: The reliable operation of this equipment. Additional equipment is necessary to handle power surges associated with intermittent renewable energy such as dispersed generation from wind or solar. Most transformers lose between 5 and 1.5 percent of their input as heat and noise. Iron losses are no-load and constant whenever the transformer is energized, while copper and auxiliary losses are proportionate to

11590-436: The rotor. Solidity is measured by the blade area divided by the rotor area. A subtype of Darrieus turbine with straight, as opposed to curved, blades. The cycloturbine variety has variable pitch to reduce the torque pulsation and is self-starting. The advantages of variable pitch are high starting torque; a wide, relatively flat torque curve; a higher coefficient of performance ; more efficient operation in turbulent winds; and

11712-413: The security of some SCADA-based systems has come into question as they are seen as potentially vulnerable to cyber attacks . In particular, security researchers are concerned about: SCADA systems are used to control and monitor physical processes, examples of which are transmission of electricity, transportation of gas and oil in pipelines, water distribution, traffic lights, and other systems used as

11834-477: The so-called smart grid . SCADA SCADA (an acronym for supervisory control and data acquisition ) is a control system architecture comprising computers , networked data communications and graphical user interfaces for high-level supervision of machines and processes. It also covers sensors and other devices, such as programmable logic controllers , which interface with process plant or machinery. The operator interfaces which enable monitoring and

11956-427: The square of the current. Auxiliary losses are due to running fans and pumps which is noisy when the transformer is operating at maximum capacity. To reduce noise, enclosures are often built around the transformer and can also be added after the substation is built. Oil-based transformers are often built with bunded areas to prevent the escape of flaming or leaking oil. Fire separation areas or firewalls are built around

12078-451: The substation must be considered, such as drainage , noise and road traffic effects. The substation site must be reasonably central to the distribution area to be served. The site must be secure from intrusion by passers-by, both to protect people from injury by electric shock or arcs, and to protect the electrical system from misoperation due to vandalism. If not owned and operated by a utility company, substations are typically occupied on

12200-452: The substation where electrical energy is being converted to heat, which indicates a problem and can cause additional damage from the high heat. Dissolved gas analysis can tell when an oil-insulated transformer needs to have the oil filtered or replace, and also detect other issues. Early electrical substations required manual switching or adjustment of equipment, and manual collection of data for load, energy consumption, and abnormal events. As

12322-420: The supporting tower. Downwind machines have been built, because they don't need an additional mechanism for keeping them in line with the wind. In high winds, downwind blades can also be designed to bend more than upwind ones, which reduces their swept area and thus their wind resistance, mitigating risk during gales. Despite these advantages, upwind designs are preferred, because the pulsing change in loading from

12444-553: The switching station is to isolate the faulty portion of the system in the shortest possible time. De-energizing faulty equipment protects it from further damage, and isolating a fault helps keep the rest of the electrical grid operating with stability. Electrified railways also use substations, often distribution substations. In some cases a conversion of the current type takes place, commonly with rectifiers for direct current (DC) trains, or rotary converters for trains using alternating current (AC) at frequencies other than that of

12566-547: The system. In April 2008, the Commission to Assess the Threat to the United States from Electromagnetic Pulse (EMP) Attack issued a Critical Infrastructures Report which discussed the extreme vulnerability of SCADA systems to an electromagnetic pulse (EMP) event. After testing and analysis, the Commission concluded: "SCADA systems are vulnerable to EMP insult. The large numbers and widespread reliance on such systems by all of

12688-434: The system. Capacitors can reduce the current in wires, helping stem system losses from voltage drop or enabling extra power to be sent through the conductors. Capacitors may be left on in response to constant inductive load or turned on when inductive load is increased, such as in the summer for air conditioners . The switching may be remote and can be done manually or automatically. Larger substations have control rooms for

12810-631: The systems should be evaluated to identify risks and solutions implemented to mitigate those risks. Wind turbine A wind turbine is a device that converts the kinetic energy of wind into electrical energy . As of 2020 , hundreds of thousands of large turbines , in installations known as wind farms , were generating over 650 gigawatts of power, with 60 GW added each year. Wind turbines are an increasingly important source of intermittent renewable energy , and are used in many countries to lower energy costs and reduce reliance on fossil fuels . One study claimed that, as of 2009, wind had

12932-464: The time of interruption, current could be normal, too high due to excessive load, unusual due to a fault, or tripped by protective relays prior to anticipated trouble. The most common technologies to extinguish the power arc from separating the conductors in the breaker include: Reclosers are similar to breakers, and can be cheaper because they do not require separate protective relays. Often used in distribution, they often are programmed to trip when

13054-427: The transformer to stop the spread of fire. Firefighting vehicles are allowed a path to access the area. Maintenance of substations involves inspections, data collection and analysis, and routine scheduled work. Using methods such as infrared scanning and dissolved gas analysis, it can be predicted when the substation will need maintenance and predict dangers before they materialize. Infrared technology finds hot spots in

13176-657: The transmission grid. Usually for economy of construction the collector system operates around 35 kV, although some collector systems are 12 kV, and the collector substation steps up voltage to a transmission voltage for the grid. The collector substation can also provide power factor correction if it is needed, metering, and control of the wind farm. In some special cases a collector substation can also contain an HVDC converter station. Collector substations also exist where multiple thermal or hydroelectric power plants of comparable output power are in proximity. Examples for such substations are Brauweiler in Germany and Hradec in

13298-401: The transmission or distribution systems. Distribution substations are typically the points of voltage regulation , although on long distribution circuits (of several miles/kilometers), voltage regulation equipment may also be installed along the line. The downtown areas of large cities feature complicated distribution substations, with high-voltage switching, and switching and backup systems on

13420-453: The transmission system to the distribution system of an area. It is uneconomical to directly connect electricity consumers to the main transmission network, unless they use large amounts of power, so the distribution station reduces voltage to a level suitable for local distribution. The input for a distribution substation is typically at least two transmission or sub-transmission lines. Input voltage may be, for example, 115 kV, or whatever

13542-447: The use of conventional networking specifications, such as TCP/IP , blurs the line between traditional and industrial networking, they each fulfill fundamentally differing requirements. Network simulation can be used in conjunction with SCADA simulators to perform various 'what-if' analyses. With increasing security demands (such as North American Electric Reliability Corporation (NERC) and critical infrastructure protection (CIP) in

13664-823: The utility often tries to minimize downtime. Substations typically serve at least one of the following purposes: A transmission substation connects two or more transmission lines. The simplest case is where all transmission lines have the same voltage. In such cases, substation contains high-voltage switches that allow lines to be connected or isolated for fault clearance or maintenance. A transmission station may have transformers to convert between two transmission voltages, voltage control / power factor correction devices such as capacitors, reactors or static VAR compensators and equipment such as phase shifting transformers to control power flow between two adjacent power systems. Transmission substations can range from simple to complex. A small "switching station" may be little more than

13786-490: The utility supplier via the electrical grid . Wind turbines are manufactured in a wide range of sizes, with either horizontal or vertical axes, though horizontal is most common. The windwheel of Hero of Alexandria (10–70 CE) marks one of the first recorded instances of wind powering a machine. However, the first known practical wind power plants were built in Sistan , an Eastern province of Persia (now Iran), from

13908-491: The visual appeal. Wind turbine design is a careful balance of cost, energy output, and fatigue life. Wind turbines convert wind energy to electrical energy for distribution. Conventional horizontal axis turbines can be divided into three components: A 1.5 ( MW ) wind turbine of a type frequently seen in the United States has a tower 80 meters (260 ft) high. The rotor assembly (blades and hub) measures about 80 meters (260 ft) in diameter. The nacelle , which contains

14030-514: The wind as each blade passes behind the supporting tower can cause damage to the turbine. Turbines used in wind farms for commercial production of electric power are usually three-bladed. These have low torque ripple , which contributes to good reliability. The blades are usually colored white for daytime visibility by aircraft and range in length from 20 to 80 meters (66 to 262 ft). The size and height of turbines increase year by year. Offshore wind turbines are built up to 8 MW today and have

14152-406: The wind speed they are designed for, from class I to class III, with A to C referring to the turbulence intensity of the wind. Conservation of mass requires that the mass of air entering and exiting a turbine must be equal. Likewise, the conservation of energy requires the energy given to the turbine from incoming wind to be equal to that of the combination of the energy in the outgoing wind and

14274-462: The yard, and the transmission lines take their power from a Feeder Bus on the other side of the yard. An important function performed by a substation is switching , which is the connecting and disconnecting of transmission lines or other components to and from the system. Switching events may be planned or unplanned. A transmission line or other component may need to be de-energized for maintenance or for new construction, for example, adding or removing

14396-471: Was a 100 kW generator on a 30-meter (98 ft) tower, connected to the local 6.3 kV distribution system. It was reported to have an annual capacity factor of 32 percent, not much different from current wind machines. In the autumn of 1941, the first megawatt-class wind turbine was synchronized to a utility grid in Vermont . The Smith–Putnam wind turbine only ran for about five years before one of

14518-858: Was able to build the first automatically operated wind turbine after consulting local University professors and his colleagues Jacob S. Gibbs and Brinsley Coleberd and successfully getting the blueprints peer-reviewed for electricity production. Although Blyth's turbine was considered uneconomical in the United Kingdom, electricity generation by wind turbines was more cost effective in countries with widely scattered populations. In Denmark by 1900, there were about 2500 windmills for mechanical loads such as pumps and mills, producing an estimated combined peak power of about 30 megawatts (MW). The largest machines were on 24-metre (79 ft) towers with four-bladed 23-metre (75 ft) diameter rotors. By 1908, there were 72 wind-driven electric generators operating in

14640-536: Was achieved using a back-up mainframe system connected to all the Remote Terminal Unit sites and was used in the event of failure of the primary mainframe system. Some first generation SCADA systems were developed as "turn key" operations that ran on minicomputers such as the PDP-11 series. SCADA information and command processing were distributed across multiple stations which were connected through

14762-418: Was believed to be a system bug. Monitoring of the system logs revealed the malfunctions were the result of cyber attacks. Investigators reported 46 separate instances of malicious outside interference before the culprit was identified. The attacks were made by a disgruntled ex-employee of the company that had installed the SCADA system. The ex-employee was hoping to be hired by the utility full-time to maintain

14884-579: Was installed by the Austrian Josef Friedländer at the Vienna International Electrical Exhibition in 1883. It was a Halladay windmill for driving a dynamo . Friedländer's 6.6 m (22 ft) diameter Halladay "wind motor" was supplied by U.S. Wind Engine & Pump Co. of Batavia , Illinois . The 3.7 kW (5 hp) windmill drove a dynamo at ground level that fed electricity into

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