Download project for last year and more Study notes Transmission Systems in PDF only on Docsity!
Project Wireless Power Transfer
System
Table Contents
- Table Content…………………………………………………………………………………………………………………………………… Chapters Page# - Table Content…………………………………………………………………………………………………………………………………… - Table Content……………………………………………………………………………………………………………………………………
- Chapter#01-Power Transmission Methods ……………………………………………………………………….. - 1.1 Power Transmission System……………………………………………………………………………………………………….. - Fig.1.1.1……………………………………………………………………………………………………………………………. - 1.2 Types of Power Transmission………………………………………………………………………………….………………….. - 1.3 Overhead Transmission Lines……………………………………………………………………………………………………… - Fig.1.3.1 ACSR Cable…………………………………………………………………………………………………………… - Fig.1.3.2……………………………………………………………………………………………………………………………… - Fig.1.3.3……………………………………………………………………………………………………………………………… - Fig.1.3.4………………………………………………………………………………………………………………………..…….
- 1.4 Sub Transmission…………………………………………………………………………………………………………………………. - Fig.1.4.1…………………………………………………………………………………………………………………………..……. - Fig.1.4.1…………………………………………………………………………………………………………………………..……. - 1.5 Underground Transmission Lines………………………………………………………………………………………………… - Fig.1.5.1………………………………………………….…..………………………………………………………………………. - Fig.1.5.2……………………………………………………………………………………………………………………………. - Fig.1.5.3……………………………………………………………………………………………………………………………. - 1.6 Wireless Power Transmission……………………….................................................................................. - Fig.1.6.1…………………………………………………………………………………………………………………………. - 1.7 History…………………………………………………………………………………………………………………………………………. - Fig.1.7.1……………………………………………………………………………………………………………………….. - Fig.1.7.2………………………………………………………………………………………………………………………… - Fig.1.7.3…………………………………………………………………………………………………………………………
- 1.8 Bulk power transmission…………………………………………………………………………………………………………………. - Fig.1.8.1…………………………………………………………………………………………………………………… - Fig.1.8.2…………………………………………………………………………………………………………………… - Fig.1.8.3……………………………………………………………………………………………………………………
- 1.9 Grid input……………………………………………………………………………………………………………………………….……….
- 1.10 Losses……………………………………………………………………………………………………………………………………………
- 1.11 Transposition……………………………………………………………………………………………………………………………….. - 1.12 Sub transmission………………………………………………………………………………………………………………………..
- 1.13 Transmission grid exit…………………………………………………………………………………………………………………..
- 1.14 Advantage of High voltage power transmission line …………………………………………………………………….
- 1.15 Modeling and the transmission matrix………………………………………………………………………………….
- 1.16 Lossless line…………………………………………………………………………………………………………………….
- 1.17 Short line ……………………………………………………………………………………………………………………….
- 1.18 Medium line ………….……………………………………………………………………………………………………….
- 1.19 Long line...………………………………………………………………………………………………………………………..
- 1.20 High voltage Direct Current …..……………….………………………………………………………………………………….
- 1.21 Capacity ………………………………….…………………………………………………………………………………………………..
- 1.22 Control ………………………………………………………………………………………………………………………………………….
- 1.23 Load Blancing …………………………………………………………………………………………………………………………….…
- 1.24 Failure Protection …………………………………………………………………………………………………………………………
- 1.25 Communications ………………………………………………………………………………………………………………………….. - Fig. 1.5.1……………………………………………….……………………………………………………………………….
- 1.26 Electricity market reform……………………..………………………………………………………………………….
- 1.27 Cost of electric power transmission ………………………………………………………………………………..
- 1.28 Merchant transmission..................................................................................................…....
- 1.29 Health concerns………………………………………………………………………………………………………………
- 1.30 Policy by country …………………………………………………………………………………………………………
- 1.31 Special transmission ...........................
- Ground ……………………………………………………………………………………………………………… Chapter #02Conductor using in Transmission over Head & under
- Fig 4.2.1………………………………………………………………………………………………………………………………….
- 4.3 Types of Best Mattel Conductor……………………………………………………………………………………….
- Fig 4.3.1 …………………………………………………………………………………………………………………………………
- Classification of transmission lines by operating voltage …………………………………..……………… ….
- Circuits........................................................................................................................................
- Bundle conductors…………………………………………………………………………………………………………………
- Ground wires…………………………………………………………………………………………………………………………
- Insulated conductors and cable……………………………………………………………………………………………..
- Dampers…………………………………………………………………………………………………………………………………
- Compact transmission…………………………………………………………………………………………………………….
- Train Power Line……………………………………………………………………………………………………………………..
- Further Application………………………………………………………………………………………………………………….
- Use of area under overhead power lines.
- Aviation accidents
- History
- Mathematical analysis
- Short and medium line model …………………………………………………………………………
- Gallery …………………………………………………………………………………………..
- Advantages …………………………………………………………………… Chapter#03-Power Transmission advantage and disadvantage
- Disadvantages…………………………………………………………………………….
- Advantages of Extra High Voltage Transmission.....................................................
- Disadvantages of High Voltage Transmission…………………………………………
- D.C. Energy Transmission System……………………………………………………...
- Advantages of DC Electrical Energy Transmission System…………………………..
- Transformer Basics Chapter #04-Power Transformer
- Single Phase Voltage Transformer …………………………………………………………..
- Transformer Construction (single-phase…………………………………………………
- A Transformers Turns Ratio………………………………………………………………..
- Transformer Basics Example No1………………………………………………………….
- Transformer Basics Example No 2………………………………………………………….
- Transformer Action ……………………………………………………………………………
- Transformer Basics Example No 3 …………………………………………………………
- Electrical Power in a Transformer …………………………………………………………
- Transformer Efficiency Triangle ……………………………………………………………
- Transformer Basics Summary………………………………………………………
- Basic Representation of the Transformer…………………………………………
- Transformer Construction…………………………………………………………
- Transformer Construction of the Core………………………………………………
- Transformer Core Types………………………………………………………………..
- Transformer Winding Arrangements……………………………………………………
- Transformer Core Losses …………………………………………………………………
- Three Phase Voltages and Currents..........................................................................
- Transformer Construction using Dot Orientation ………………………………………..
- Three Phase Transformers……………………………………………………………….
Chapter#01-Power Transmission Methods
Power Transmission System: Most transmission lines are high-voltage three- phase alternating current (AC), although single phase AC is sometimes used in railway electrification systems. High-voltage direct-current (HVDC) technology is used for greater efficiency over very long distances (typically hundreds of miles). HVDC technology is also used in submarine power cables (typically longer than 30 miles (50 km)), and in the interchange of power between grids that are not mutually synchronized. HVDC links are used to stabilize large power distribution networks where sudden new loads, or blackouts, in one part of a network can result in synchronization problems and cascading failures. Fig.1.1. Diagram of an electric power system; transmission system is in blue Electricity is transmitted at high voltages (66 kV or above) to reduce the energy loss which occurs in long-distance transmission. Power is usually transmitted through overhead power lines. Underground power transmission has a significantly higher installation cost and greater operational limitations, but reduced maintenance costs. Underground transmission is sometimes used in urban areas or environmentally sensitive locations. A lack of electrical energy storage facilities in transmission systems leads to a key limitation. Electrical energy must be generated at the same rate at which it is consumed. A sophisticated control system is required to ensure that the power generation very closely matches the demand. If the demand for power exceeds supply, the imbalance can cause generation plant(s) and transmission equipment to automatically disconnect or shut down to prevent damage. In the worst case, this may lead to a cascading series of shut downs and a major regional blackout. Examples include the US Northeast blackouts
of 1965 , 1977 , 2003 , and major blackouts in other US regions in 1996 and 2011. Electric transmission networks are interconnected into regional, national, and even continent wide networks to reduce the risk of such a failure by providing multiple redundant, alternative routes for power to flow should such shut downs occur. Transmission companies determine the maximum reliable capacity of each line (ordinarily less than its physical or thermal limit) to ensure that spare capacity is available in the event of a failure in another part of the network.
Types of Power Transmission:
1. Overhead Transmission Lines
2. Sub transmission Lines
3. Underground Transmission Lines
4. Wireless Power Transmission
Overhead Transmission Lines
A typical ACSR. The conductor consists of seven strands of steel surrounded by four layers of aluminum . Fig.1.3.1 ACSR Cable High-voltage overhead conductors are not covered by insulation. The conductor material is nearly always an aluminum alloy, made into several strands and possibly reinforced
but are occasionally used on long lines with light loads. Voltages less than 33 kV are usually used for distribution. Voltages above 765 kV are considered extra high voltage and require different designs compared to equipment used at lower voltages. Since overhead transmission wires depend on air for insulation, the design of these lines requires minimum clearances to be observed to maintain safety. Adverse weather conditions, such as high winds and low temperatures, can lead to power outages. Wind speeds as low as 23 knots (43 km/h) can permit conductors to encroach operating clearances, resulting in a flashover and loss of supply.[2]^ Oscillatory motion of the physical line can be termed conductor gallop or flutter depending on the frequency and amplitude of oscillation. Fig.1.3.4 Three abreast Electrical Pylons in Webster, Texas
Sub transmission Lines
A 115 kV sub transmission line in the Philippines, along with 20 kV distribution lines and a street light, all mounted in a wood sub transmission pole Fig.1.4.
Fig1.4.2 115 kV H-frame transmission tower Sub transmission is part of an electric power transmission system that runs at relatively lower voltages. It is uneconomical to connect all distribution substations to the high main transmission voltage, because the equipment is larger and more expensive. Typically, only larger substations connect with this high voltage. It is stepped down and sent to smaller substations in towns and neighborhoods. Sub transmission circuits are usually arranged in loops so that a single line failure does not cut off service to many customers for more than a short time. Loops can be "normally closed", where loss of one circuit should result in no interruption, or "normally open" where substations can switch to a backup supply. While sub transmission circuits are usually carried on overhead lines, in urban areas buried cable may be used. The lower-voltage sub transmission lines use less right-of-way and simpler structures; it is much more feasible to put them underground where needed. Higher-voltage lines require more space and are usually above-ground since putting them underground is very expensive. There is no fixed cutoff between sub transmission and transmission, or sub transmission and distribution. The voltage ranges overlap somewhat. Voltages of 69 kV, 115 kV, and 138 kV are often used for sub transmission in North America. As power systems evolved, voltages formerly used for transmission were used for sub transmission, and sub transmission voltages became distribution voltages. Like transmission, sub transmission moves relatively large amounts of power, and like distribution, sub transmission covers an area instead of just point-to-point.
Underground Transmission Lines
Electric power can also be transmitted by underground power cables instead of overhead power lines. Underground cables take up less right-of-way than overhead lines, have
Fig.1.5.
Wireless Power Transmission
Wireless power transfer (WPT), wireless power transmission, wireless energy transmission (WET), or electromagnetic power transfer is the transmission of electrical energy without wires as a physical link. In a wireless power transmission system, a transmitter device, driven by electric power from a power source, generates a time- varying electromagnetic field, which transmits power across space to a receiver device, which extracts power from the field and supplies it to an electrical load. The technology of wireless power transmission can eliminate the use of the wires and batteries, thus increasing the mobility, convenience, and safety of an electronic device for all users. Wireless power transfer is useful to power electrical devices where interconnecting wires are inconvenient, hazardous, or are not possible. Wireless power techniques mainly fall into two categories, near field and far-field. In near field or non-radiative techniques, power is transferred over short distances by magnetic fields using inductive coupling between coils of wire, or by electric fields using capacitive coupling between metal electrodes. Inductive coupling is the most widely used wireless technology; its applications include charging handheld devices like phones and electric toothbrushes, RFID tags, induction cooking, and wirelessly charging or continuous wireless power transfer in implantable medical devices like artificial cardiac pacemakers, or electric vehicles. In far-field or radiative techniques, also called power beaming , power is transferred by beams of electromagnetic radiation, like microwaves or laser beams. These techniques can transport energy longer distances but must be aimed at the receiver. Proposed applications for this type are solar power satellites, and wireless powered drone aircraft. An important issue associated with all wireless power systems is limiting the exposure of people and other living beings to potentially injurious electromagnetic fields.
Fig.1.6.
History
Fig.1.7. Working for Westinghouse, William Stanley Jr. spent his time recovering from illness in Great Barrington installing what is considered the world's first practical AC transformer system. Working from what he considered an impractical Gaulard-Gibbs design, electrical engineer William Stanley, Jr. developed what is considered the first practical series AC transformer in 1885. Working with the support of George Westinghouse, in 1886 he demonstrated a transformer based alternating current lighting system in Great Barrington, Massachusetts. Powered by a steam engine driven 500 V Siemens generator, voltage was stepped down to 100 Volts using the new Stanley transformer to power incandescent lamps at 23 businesses along main street with very little power loss over 4,000 feet (1,200 m). This practical demonstration of a transformer and alternating current lighting system would lead Westinghouse to begin installing AC based systems later that year. 1888 saw designs for a functional AC motor, something these systems had lacked up till then. These were induction motors running on polyphase current, independently invented by Galileo Ferraris and Nikola Tesla (with Tesla's design being licensed by Westinghouse in the US). This design was further developed into the modern practical three-phase form by Mikhail Dolivo-Dobrovolsky and Charles Eugene Lancelot Brown. Practical use of these types of motors would be delayed many years by development problems and the scarcity of poly-phase power systems needed to power them. The late 1880s and early 1890s would see the financial merger of smaller electric companies into a few larger corporations such as Ganz and AEG in Europe and General Electric and Westinghouse Electric in the US. These companies continued to develop AC systems but the technical difference between direct and alternating current systems would follow a much longer technical merger. Due to innovation in the US and Europe, alternating current's economy of scale with very large generating plants linked to loads via long-distance transmission was slowly being combined with the ability to link it up with
all of the existing systems that needed to be supplied. These included single phase AC systems, poly-phase AC systems, low voltage incandescent lighting, high voltage arc lighting, and existing DC motors in factories and street cars. In what was becoming a universal system , these technological differences were temporarily being bridged via the development of rotary converters and motor-generators that would allow the large number of legacy systems to be connected to the AC grid. These stopgaps would slowly be replaced as older systems were retired or upgraded. Fig.1.7. Westinghouse alternating current polyphase generators on display at the 1893 World's Fair in Chicago, part of their "Tesla Poly-phase System". Such polyphase innovations revolutionized transmission The first transmission of single-phase alternating current using high voltage took place in Oregon in 1890 when power was delivered from a hydroelectric plant at Willamette Falls to the city of Portland 14 miles (23 km) downriver.[17]^ The first three-phase alternating current using high voltage took place in 1891 during the international electricity exhibition in Frankfurt. A 15 kV transmission line, approximately 175 km long, connected Lauffen on the Neckar and Frankfurt. Voltages used for electric power transmission increased throughout the 20th century. By 1914, fifty-five transmission systems each operating at more than 70 kV were in service. The highest voltage then used was 150 kV. By allowing multiple generating plants to be interconnected over a wide area, electricity production cost was reduced. The most efficient available plants could be used to supply the varying loads during the day. Reliability was improved and capital investment cost was reduced, since stand-by generating capacity could be shared over many more customers and a wider geographic area. Remote and low-cost sources of energy, such as hydroelectric power or mine- mouth coal, could be exploited to lower energy production cost. The rapid industrialization in the 20th century made electrical transmission lines and grids critical infrastructure items in most industrialized nations. The interconnection of local generation plants and small distribution networks was spurred by the requirements of World War I, with large electrical generating plants built by governments to provide power to munitions factories. Later these generating plants were connected to supply civil loads through long-distance transmission
The increase in voltage is achieved in AC circuits by using a step- up transformer. HVDC systems require relatively costly conversion equipment which may be economically justified for particular projects such as submarine cables and longer distance high capacity point-to-point transmission. HVDC is necessary for the import and export of energy between grid systems that are not synchronized with each other. A transmission grid is a network of power stations, transmission lines, and substations. Energy is usually transmitted within a grid with three-phase AC. Single-phase AC is used only for distribution to end users since it is not usable for large polyphase induction motors. In the 19th century, two-phase transmission was used but required either four wires or three wires with unequal currents. Higher order phase systems require more than three wires, but deliver little or no benefit. Fig.1.8. The synchronous grids of the European Union The price of electric power station capacity is high, and electric demand is variable, so it is often cheaper to import some portion of the needed power than to generate it locally. Because loads are often regionally correlated (hot weather in the Southwest portion of the US might cause many people to use air conditioners), electric power often comes from distant sources. Because of the economic benefits of load sharing between regions, wide area transmission grids now span countries and even continents. The web of interconnections between power producers and consumers should enable power to flow, even if some links are inoperative.
The unvarying (or slowly varying over many hours) portion of the electric demand is known as the base load and is generally served by large facilities (which are more efficient due to economies of scale) with fixed costs for fuel and operation. Such facilities are nuclear, coal-fired or hydroelectric, while other energy sources such as concentrated solar thermal and geothermal power have the potential to provide base load power. Renewable energy sources, such as solar photovoltaics, wind, wave, and tidal, are, due to their intermittency, not considered as supplying "base load" but will still add power to the grid. The remaining or 'peak' power demand, is supplied by peaking power plants, which are typically smaller, faster-responding, and higher cost sources, such as combined cycle or combustion turbine plants fueled by natural gas. Long-distance transmission of electricity (hundreds of kilometers) is cheap and efficient, with costs of US$0.005–0.02 per kWh (compared to annual averaged large producer costs of US$0.01–0.025 per kWh, retail rates upwards of US$0.10 per kWh, and multiples of retail for instantaneous suppliers at unpredicted highest demand moments).[21]^ Thus distant suppliers can be cheaper than local sources (e.g., New York often buys over 1000 MW of electricity from Canada).[22]^ Multiple local sources (even if more expensive and infrequently used) can make the transmission grid more fault tolerant to weather and other disasters that can disconnect distant suppliers. Fig.1.8. A high-power electrical transmission tower, 230 kV, double-circuit, also double-bundled Long-distance transmission allows remote renewable energy resources to be used to displace fossil fuel consumption. Hydro and wind sources cannot be moved closer to populous cities, and solar costs are lowest in remote areas where local power needs are minimal. Connection costs alone can determine whether any particular renewable alternative is economically sensible. Costs can be prohibitive for transmission lines, but various proposals for massive infrastructure investment in high capacity, very long distance super grid transmission networks could be recovered with modest usage fees.
Grid input
