substation design

SUBSTATION DESIGN ENGINEERING & CONSTRUCTION BY D.K.DHAR Saransh Sharma General Manager, CVPP Ltd. T.E, CVPP Ltd. ABSTRACT Many urban utilities are evaluating and upgrading their transmission and distribution systems to provide adequate and reliable power to meet their growing business and residential area needs. Limited areas for new substations in congested urban areas, the requirement to obtain city permits and community approval, as well as the need to provide uninterrupted service to customers during construction, requires innovative, flexible and cost efficient substation designs. In this paper we review that substation is an important element in the power transmission system. Proper design, engineering, construction, testing and commissioning of substation is very important for the reliability of the substation and accommodating future expansion. Establishment of substation/switchyard compromise of careful Design/Engineering of civil, structural, electrical, communication protection and SCADA aspects. Civil construction and electrical erection is also very important for good performance of the equipment in particular and the substation in general. 1. INTRODUCTION An electric Substation is a subsidiary of an electricity generation, transmission and distribution system where voltage is transformed from high to Low or the reverse using transformers. Electric Power flows through several substations between generating plant & consumer changing the voltage level in several stages. A Substation that has a step up transformer increases the voltage with increasing the current for domestic and commercial distribution. The word substation comes from the days before the distribution system become a grid. At first Substation were connected to only one power station where the generation was housed and were subsidiaries of that power station. Technological advancements in design and construction practices have revolutionized the concept of substation engineering; Smart Grid is a necessity of the day as there is a National Integration of transmission network. 2. CIVIL AND STRUCTURAL ENGINEERING: Site selection for substation and ROW problems in outlets:- The location requirements for substations are site specific, and are determined by practicalities of engineering constraints, connection costs, environmental issues and impacts on social attributes. Generally, the location in which a substation is to be sited is dictated by load location and transmission line arrangements for connection of the substation to the grid, and the substation to the place where the connection is required. Access to the substation sites must be capable under all but the most extreme conditions. In response to State Planning Policy Guideline 1/03, Power link substations shall be able to function effectively through a 1 in 200 year flood event. Site selection, substation design and layout shall be such that the substation continues to function through this flood event. The site must not be within the Q200 flood inundation area, and be proximal to secure road access or be in a position where an all weather access road can be constructed. Existing land uses must not hinder access, nor limit the potential configuration of lines entering and leaving the substation. The substation site and access should also minimize the impact upon the continuation of the existing surrounding land uses. Coal mining, in particular, is very active in the area and the establishment of a substation within ML tenements has the following specific impacts: The holder of the mining lease is entitled to compensation for coal that is sterilized by the substation. Requirement to comply with mine OH&S and other operational restrictions if the mining lease needs to be crossed to access the substation; and Consent is required from the holder of a mining lease before entering onto the connecting transmission line easements or erecting any structure on the easement land. FACTORS GOVERNING THE SELECTION OF SITE: Voltage levels, voltage regulation, the cost of sub transmission, substation, primary feeder mains and distribution transformers dictate the location of a substation. However, the following rules are to be considered for the selection of an ideal location for a substation: The substation should be located nearer the load centre of its service areas, so that its distance from the substation is minimum. Proper voltage regulation should be possible without taking extensive measures. There should be proper access for incoming sub-transmission lines and outgoing primary feeders. It should provide enough space for future expansion. It should help minimize the number of customers affected by any service interruption. 3. Contouring, Cutting/Filling/Leveling The alignment of the transmission line shall be most economical from the point of view of construction and maintenance. Routing of transmission line through protected/reserved forest area should be avoided. In case it is not possible to avoid the forest or area having large trees completely, then keeping in view the overall economy the route should be aligned in such a way that cutting of trees is minimum. The route should have minimum coverings of major rivers, railway lines, National/state highways, overhead EHV power lines and communication lines. Preferable to utilize level ground for the alignment. The level up and down of each pit centre with respect to center of tower location shall be recorded at intervals of 2 meters using totals solutions /DGPS/digital the o b -dolite and digitized contour plans, the quantities of benching & protection work via possible unequal leg extensions shall be optimized using suitable computer aided techniques/software. Required tower & foundation details, cost data for comparative elevation of benching & protection work via unequal leg extensions shall be provided by contractor to the owner before execution stage. The changes desired by the owner in the preliminary tower schedule or as may be required based on detailed survey of tower locations & contouring by the contractor shall be carried out by the contractor and the final tower schedule shall be submitted for approval of the owner. The Tower schedule shall show positions of all type of towers, span length, type of foundation for each tower, benching and revetment requirement, unequal leg extensions, elevation at all angles, crossing & other details etc. An obstacle detection approach based on contour view synthesis for inspection robot on transmission line is presented in this paper. When the robot is offline, the virtual contour images for multiple view of obstacles are reconstructed, in which the contours of obstacles are extracted by means of gradient magnitude based contour extraction algorithm, and the corresponding points on the left and right image can be found by using region matching algorithm, then view synthesis technique is adopted to reconstruct multi-view of obstacles and a virtual contour image library built; when the robot is online, the obstacle can be recognized by matching the extracted contour of obstacle on transmission line and the virtual contours contours in the image library built beforehand. The experiment results show the ideal recognition can be achieved ground on the contour view synthesis approach for obstacle detection the effectiveness of this method can be demonstrated by the comparing experiments as well. 4. Gantry and Equipment support structures:-These structures include Gantries and Equipment Support Structures. Gantry structures are mainly used for guiding the power conductor from last tower near substation to the electrical equipments in a substation. This structure consists of a number of columns and Girder beams, which depend on number of circuits of the line. Gantries are also used for line crossing. Power conductors of one line can be under passed with the help of required number of gantries. Equipment Support Structures are columns, supporting electric equipments in a substation. Depending upon the site and client's requirement, the Gantry and Equipment support structures can be mounted on substation building also. Substation is a high-voltage electric system facility. It is used to switch generators, equipment, and circuits or lines in and out of a system. Substation includes Gantries and Equipment Support Structures. Gantry structures are mainly used for guiding the power conductor from last tower near substation to the electrical equipments in a substation. This structure consists of a number of columns and Girder beams, which depend on number of circuits of the line. Gantries are also used for line crossing. Power conductors of one line can be underpasses with the help of required number of gantries. Equipment Support Structures are columns, supporting electric equipments in a substation. Depending upon the site and client's requirement, the Gantry and Equipment support structures can be mounted on substation building also. MEGATRO mainly provide every type of substation gantries structure, we manufacture them with complicated technology and adopted sophisticated production line. Fabrication: conform to clients drawings and technical requirements Place of Origin: Qingdao, Shandong, China. Availability size: Based on the customer’s requirements. Material: Chinese material or as per clients requirements Package: both party discuss and agreed before delivery Terms of Payment: L/C; T/T Minimum Order Quantity: 10tons Port of Loading: Qingdao Port Lead Time: one month or based on the customer's needs. Performance Standard Besides conform to the drawing and design, the materials and fabrication of tower components shall conform to Chinese Standards or international standard 5. Lighting and Lightning mast:- High-mast lighting is a tall pole with lighting attached to the top pointing towards the ground, usually but not always used to light a highway or recreational field. The pole that the lighting is mounted on is generally at least 30 meters (98 ft) tall (under this height it is referred to as conventional lighting system), while the lighting consists of a luminaries ring surrounding the pole with one or several independent lighting fixtures mounted around it. Some units have the lighting surrounded by a circular shield to prevent or reduce light pollution or light trespass from affecting neighborhoods adjacent to the highway. Maintenance of these systems are done by lowering the luminary ring from the mast head to the base using a winch and motor[4] to the ground or at a height accessible by a cherry picker and located in areas to allow for easier access without distrusting traffic. Light mast is a tall lighting specified [clarification needed] mast, which has several big searchlights on top of it. Light masts illuminate’s large areas and are possible to move, which is why they are used (for example) as farming, construction and emergency works implement. The device works with its own electric generator or with external power source. 6. Communication mast: An observation tower is a structure used to view events from a long distance and to create a full 360 degree range of vision. They are usually at least 20 meters (65.6 ft) tall and made from stone, iron, and wood. Many modern towers are also used as TV towers, restaurants, or churches. The towers first appeared in Germany at the end of the 18th century,[citation needed] and their numbers steadily increased, especially after the invention of the elevator. Observation towers that are used as guard posts or observation posts over an extended period to overlook an area are commonly called watchtowers instead. Observation towers are an easily visible sight on the countryside, as they must rise over trees and other obstacles to ensure clear vision. Older control rooms have often been likened to medieval chambers. The heavy use of stone, iron, and wood in their construction helps to create this illusion. Modern towers frequently have observation decks or terraces with restaurants or on the roof of mountain stations of an aerial ropeway. Frequently observation towers are used also as location of radio services within the UHF/VHF range (FM sound broadcasting, TV, public rural broadcasting service, and portable radio service). In some cases this usage of the tower is at least as important as its use as an observation tower. Such towers are usually called TV towers or telecommunication towers. Many towers are also equipped with a tower restaurant and allow visitors access via elevators. Also common is the usage of water towers as observation towers. As in the case of TV towers the visitor will usually reach the observation deck by elevator, which is usually at a lower height above ground The typical height of the observation deck of water towers is 20 meters up to 50 meters, while the typical height of the platform of TV towers is from 80 meters up to 200 meters. Finally, some church towers may have observation decks, albeit often without an elevator. Many other buildings may have towers which allow for observation. 7. Control Room: - When considering improving the efficiency of plant operation, major focus is put on process units, control systems and production or operation management. However, it is also important to prepare a comfortable and safe environment for operators, who are trying to operate the plant more efficiently every day using control systems. Yokogawa has designed more than 500 control rooms for various industries for over 30 years. Yokogawa also participated in the ISO technical committee in drawing up the ISO 11064 “Ergonomic design of control centres (1)” (ISO: International Organization for Standardization), one of the international standards for designing control rooms. This paper provides an outline of the Control Room Design service which Yokogawa offers based on its experience, which is one of the Vigilant Plant Services launched to help improve operations throughout the plant lifecycle, as a partner of customers. Basically control room design is different from general offices, it is important to design control rooms on the basis of the human-centered design approach by balancing comfort and functionality including the following aspects. ● Plant operation tasks and organization for operation (normal situations and emergencies) ● Design standards for control rooms (ISO 11064, industry standards including customer’s standards) ● Study items based on ergonomics (layout, lighting, coloring, sound, operator console design, large screen, and selection of furniture and materials) Human-centered design approachYokogawa set the process from design to installation and construction of a control room as follows referring to ISO 11064. 1) Conceptual Design 2) Basic design 3) Detailed design 4) Installation and construction Conceptual design is particularly important. This is where the design policy and the customer’s requests are confirmed and issues in the subsequent processes (basic design, detailed design, installation and construction) will be identified prior to the basic design and detailed design. It is also important for improving the efficiency of the entire designing works. 8. Storm water drains culverts and Roads: A culvert is a structure that allows water to flow under a road, railroad, trail, or similar obstruction. Typically embedded so as to be surrounded by soil, a culvert may be made from a pipe, reinforced concrete or other material. A structure that carries water above land is known as an aqueduct. Culverts may be used to form a bridge-like structure to carry traffic. Culverts come in many sizes and shapes including round, elliptical, flat-bottomed, pear-shaped, and box-like constructions. Culverts may be made of concrete, galvanized steel, aluminum, or plastic, typically high density polyethylene. Two or more materials may be combined to form composite structures. For example, open-bottom corrugated steel structures are often built on concrete footings. Plastic culvert liners are also inserted into failing concrete or steel structures in order to repair the structure without excavating and closing the road. To prevent the older structure from collapsing, the space between it and the plastic liner is usually filled with grout. Culverts fail due to corrosion of the materials from which they are made, or erosion of the soil around or under them. If the failure is sudden and catastrophic, it can result in injury or loss of life. Sudden road collapses are often at poorly designed culvert crossing sites. Water passing through undersized culverts will scour away the surrounding soil over time. This can cause a sudden failure during medium sized rain events. Continued inspection, maintenance, and replacement of these structures is crucial for infrastructure and safety. Accidents due to culverts can also occur if a flood overwhelms it, or disrupts the road or railway above it. Safe and stable stream crossings can accommodate wildlife and protect stream health while reducing expensive erosion and structural damage. Undersized and poorly placed culverts can cause problems for water quality and aquatic organisms. Poorly designed culverts can degrade water quality via scour and erosion and also restrict aquatic organisms from being able to move freely between upstream and downstream habitat. Fish are a common victim in the loss of habitat due to poorly designed crossing structures. Culverts that offer adequate aquatic organism passage reduce impediments to movement of fish, wildlife and other aquatic life that require in stream passage. These structures are less likely to fail in medium to large scale rain/snow melt events. This culvert cannot accommodate wildlife passage Poorly designed culverts are also more apt to become jammed with sediment and debris during medium to large scale rain events. If the culvert cannot pass the water volume in the stream, the water may overflow over the road embankment. This may cause significant erosion, washing out the culvert. The embankment material that is washed away can clog other structures downstream, causing them to fail as well. It can also damage crops and property. A properly sized structure and hard bank armoring can help to alleviate this pressure. 9. Water Supply, Rain water Harvesting and Sanitary system: Rainwater harvesting is the accumulation and deposition of rainwater for reuse before it reaches the aquifer. Uses include water for garden, water for livestock, water for irrigation, and indoor heating for houses etc. In many places the water collected is just redirected to a deep pit with percolation. The harvested water can be used as drinking water as well as for storage and other purpose like irrigation. Rainwater harvesting provides an independent water supply during regional water restrictions and in developed countries is often used to supplement the main supply. It provides water when there is a drought, can help mitigate flooding of low-lying areas, and reduces demand on wells which may enable ground water levels to be sustained. It also helps in the availability of potable water as rainwater is substantially free of salinity and other salts. The concentration of contaminants is reduced significantly by diverting the initial flow of run-off water to waste. Improved water quality can also be obtained by using a floating draw-off mechanism (rather than from the base of the tank) and by using a series of tanks, with draw from the last in series. The stored rainwater may need to be analyzed properly before use in a way appropriate to ensure its safe use The quality of collected rainwater is generally better than that of surface water. Contamination is always possible by airborne dust and mists, bird feces, and other debris, so some treatment may be necessary, depending on how the water will be used. Rainwater harvesting systems can be installed with minimal skills. The system should be sized to meet the water demand throughout the dry season since it must be big enough to support daily water consumption. Specifically, the rainfall capturing area such as a building roof must be large enough to maintain adequate flow. The water storage tank size should be large enough to contain the captured water. Rain water harvesting is possible by growing fresh water flooded forests without losing the income from the used /submerged land.] The main purpose of the rain water harvesting is to utilize the locally available rain water to meet water requirements throughout the year without the need of huge capital expenditure. This would facilitate availability of uncontaminated water for domestic, industrial and irrigation needs. Instead of using the roof for catchment, the Rain Saucer, which looks like an upside down umbrella, collects rain straight from the sky. This decreases the potential for contamination and makes potable water for developing countries a potential application.[  Other applications of this free standing rainwater collection approach are sustainable gardening and small plot farming. A sanitary sewer (also called a foul sewer) is an underground carriage system specifically for transporting sewage from houses and commercial buildings through pipes to treatment or disposal. Sanitary sewers serving industrial areas also carry industrial. The system of sewers is called sewerage. All sewers deteriorate with age, but infiltration/inflow is a problem unique to sanitary sewers, since both combined sewers and storm drains are sized to carry these contributions. Holding infiltration to acceptable levels requires a higher standard of maintenance than necessary for structural integrity considerations of combined sewers. 10. Chain link fencing, compound boundary wall:- A chain-link fence (also referred to as wire netting, wire-mesh fence, chain-wire fence, cyclone fence, hurricane fence, or diamond-mesh fence) is a type of woven fence usually made from galvanized or LLDPE-coated steel wire. The wires run vertically and are bent into a zigzag pattern so that each "zig" hooks with the wire immediately on one side and each "zag" with the wire immediately on the other. This forms the characteristic diamond pattern seen in this type of fence. The popularity of chain-link fence is due to its relatively low cost and eases of installation. A further advantage is that due to the open weave, chain-link fences are transparent, and do not obscure sunlight from either side of the fence. One can make a chain-link fence semi-opaque by inserting slats into the mesh. The installation of chain-link fence involves setting posts into the ground and attaching the fence to them. The posts may be steel tubing, timber or concrete and may be driven into the ground or set in concrete. End, corner or gate posts, commonly referred to as "terminal posts", must be set in concrete footing or otherwise anchored to prevent leaning under the tension of a stretched fence. Posts set between the terminal posts are called "line posts" and are set at intervals not to exceed 10 feet. The installer attaches the fence at one end, stretches it, and attaches at the other, easily removing the excess by "unscrewing" a wire. Finally, the installer ties the fence to the line posts with aluminum wire. In many cases, the installer stretches a bottom tension wire, sometimes referred to as "coil wire", between terminal posts to help minimize the in and out movement that occurs at the bottom of the chain-link mesh between posts. Top horizontal rails are used on most chain-link fences, although not necessary. Bottom rails may be added in lieu of bottom tension wires, and for taller fences, 10 feet or more, intermediate horizontal rails are often added. Once stretched, a bottom wire should be secured to the line posts and the chain-link mesh "hog ringed" to the tension wire 2' on centre. One generally installs this wire before installing the chain-link mesh. 9. Landscaping & Aesthetics: Landscaping refers to any activity that modifies the visible features of an area of land, including: Living Elements, such as flora or fauna; or what is commonly known to as gardening, the art and craft of growing plants with a goal of creating a beautiful environment within the landscape. Natural Elements such as landforms, terrain shape and elevation, or bodies of water; Human Elements such as structures, buildings, fences or other material objects created and/or installed by humans; and Abstract Elements such as the weather and lighting conditions. Landscaping requires expertise in science and artistic design. Construction requires study and observation. It is not the same in different parts of the world. Landscaping varies according to different regions. Therefore normally local natural experts are recommended if it is done for the first time. Understanding of the site is one of the chief essentials for successful landscaping. Different natural features like terrain, topography, soil qualities, prevailing winds, depth of the frost line, and the system of native flora and fauna must be taken into account. Sometimes the land is not fit for landscaping. In order to landscape it, the land must be reshaped. This reshaping of land is called grading. Removal of earth from the land is called cutting while when earth is added to the slope, it is called filling. Sometimes the grading process may involve removal of excessive waste, soil and rocks, so designers should take into account while in the planning stage. The term “aesthetics” is commonly used by landscape architects as a synonym for style or form. However, aestheticians, designers and psychologists recognize that aesthetics have the power to change how we perceive the world around us. Therefore, a deeper understanding of aesthetics – its underlying philosophy and its translation into design – has the power to change people’s responses to their environment. The increasing importance and worth attributed to the aesthetic qualities of nature in the twentieth century led to a more inclusive understanding of aesthetics. Susan Fagin defined modern aesthetics as the “branch of philosophy that examines the nature of art and the character of our experience of art and of the natural environment.” She described four components important to aesthetics: aesthetic attitude – special kind of attitude required to aesthetically appreciate art or nature aesthetic experience – special type of experience that can be differentiated from other types of experiences aesthetic value – distinctive value different from other types of values such as economic, religious or moral Aesthetic object – special object that can be called aesthetic. 2 For landscape architects, the two components that are important to understand are the aesthetic experience (or the response a user has to a designed landscape) and the aesthetic objects that provoke the aesthetic experience. CONCLUSION: Technology advancements in the design and construction practices have revolutionized the concept of substation engineering. With the advent of smart grid era, the discussion has been centered on the ability to predict and intelligently respond to the behavior and action of all electric power users connected to it in order to efficiently deliver reliable, economic and sustainable electricity service. Smart Grid is a necessity of the day as there is a national integration of transmission network. In Europe, one of the goals of the smart grid is to significantly reduce the environment impact of the whole electricity supply system. In United state, the work on this goal has been to reduce losses and consumption through voltage optimization. 10