Generation of High Voltage in Modern Ships - Assignment Example

Name Task Tutor Date Generation of high voltage in modern ships Introduction High voltage electricity generation refers to the transfer of bulky of electric-energy from the generating plant which can renewable or non-renewable to smaller stations which are located close to population sites. The renewable energy source are those energy sources that can be restored after use and include; solar, wind and the geothermal while the non- renewable sources refers to those sources whose supply cannot be restored after use like the natural gas, nuclear energy and coal. High voltage is therefore different from the normal electricity distribution whereby there is a wire connection between the small high voltage stations and the customers. In high voltage electricity generation in ships transmission wires are connected to one another to form networks. In shipping- electrification-system, a three phase- alternating current is normally used as transmission lines. This technology is only used for distances that are too long basically distances that are more than 400 miles (600 km), for under sea cables that are longer than 30 miles (50 km) and to connect two AC networks which have not been synchronized. Normally electricity transmission is done at a high voltage (more than 110 KV) in order to reduce the loss of energy during the transmission distance which is long. The transmission of power is done through overhead power- lines. Underground power- transmission normally have a significant high cost and higher operational; limitations although it is in sensitive locations or urban areas. This paper will discuss in details how the voltages can be generated in modern ships. Discussion The major limitation in electricity distribution and generation is that in some situations electrical energy is hard to store and as a result there is need to generate it when it is required. This becomes trickier when the whole process demands storage and generation in one system. In order to ensure that there is a balance between electricity generation and demand, there is need to invent a sophisticated control mechanism. This is a major principle in electricity generation because there is the risk of the generating plant and the transmitting equipment shutting down if the demand- and- supply factors are not in a balance and this can result to regional black out like the one that occurred in US Northwest and California in 1996. Therefore in order to avoid such cases, electric- transmission-networks are thus interconnected national, regional or continent wide thus ensuring that there is the provision of alternative power flow routes if equipment failure occurs. The control mechanism so stated will assist in enhancing that the power is kept at a constant in the ship so as to support the internal system. Reduction of energy loss due to the wire resistance is also a major principle in electricity generation. High voltage can be used to reduce this energy loss. Current is proportional to circuit power, while the loss of power in the form of heat in wires has the same proportion with current squared. Since power has the same proportion with voltage, a trade off between high voltage and lower current can occur. As a result high voltage results to less power loss. Resistance reduction which can achieve through in the conductor diameter can effectively reduce power loss even though large conductors are expensive and heavy to carry. Failure protection is also a major principle in electricity generation which can be avoided through communication. Since high-voltage DC uses long transmission-lines the operators require a communication system that is reliable, this is important for power grid control and also distributing facilities. Communication between the two ends is important to monitor power flow in-and-out of protected-line section in order that faulty equipment or conductor can be quickly diagnosed and system balance restored. Short circuits in the transmission lines and other faults if not protected can make telecommunication un-reliable. There is need therefore to select a communication system which is reliable like microwaves, power line communication or optical fibers. Transmission lines determine limits the amount of power to be transmitted. The length of the wire determines this amount; short lines for instance results to conductors heating thus setting the thermal limit. Conductors sag as a result of drawing much current and damage to the equipment due to heat may happen. Ideally, power that flow via an AC line have the same proportion with the phase -angle sine of receiving voltage and the transmitting and. This angle should not tend to be cross to 90 degrees because the angle varies according to the generation and the system loading. Phase shifting transformers or series capacitors are used to improve stability on most long wires. Distributed-temperature-sensing is used to measure real-time temperature when monitoring the capacity of the capacity of the transmission system. Optic fibers are used to sense temperature in monitoring solution by either integrating them inside a high-voltage cable or mounting them externally on the insulation cable. During electricity generation health consideration is an important factor to put into focus. Current as result of low power, electromagnetic-radiation poses serious health hazard to the life of human being. It has been found out that people living or those who work near to lines of power are affected by various diseases that do not live near to power lines. Magnetic fields that are above 101 µT have been proven to have acute biological effects to human body. In a home residence there is non limited or carcinogenicity in people leukemia which is associated with some average exposure to some residential power/frequency magnetic fields found in of which are about 0.11 µT in the northern American and 0.07 µT in Europe. These impacts therefore can have long and short term effects on the life of human beings and should be put into consideration. The authority on electricity generation is exercised by they local authority, they control the grid of electricity generation and ensures that there are put in place disincentives for states to benefit more than them. In order to make instate-commerce in electricity trade easy, disincentives have to be derived by localities with cheap electricity because any other region will have a chance to drive-up rates and create competition for the local energy. Some electricity generation regulators for instance are not willing to address the problem of congestion as this congestion the generation rates low. However some local authorities’ permits or stops electricity generation owing to the impacts it can have for instance health, environment or visual impacts. An example of the government policy control in electricity generation is in the US where the rate of generation has grown four times than the transmission rates, but for transmission rates to grow big there is need for by multiple states, interlocking permits, and for the five hundred companies that are grid owners to cooperate. Interest in significant growth of electricity transmission by the national security of the US led to the enactment of the energy act of 2005 that gave the energy department the power to approve the transmission when the states refused to act. During electricity generation here several practical considerations that should be put into focus. When designing transmission-networks engineers should consider the network safety, redundancy and also economic factors while at the same time transport the energy efficiently via the transmission networks. The transmission networks are composed of cables, switches, transformers, circuit breakers and power lines. The efficiency in transmission is improved by continuous increase in voltage by using a set-up-transformer that is meant to reduce the current in conductors in use and at the same time keeping the transmitted power close equal to the power in-put. The lowered current in the power lines help in reducing the loss of power by in conductors. This can be illustrated by using Joule law theory that states that energy lost is directly- proportional to the square of the current. The result of this is that current reduction by factor 2 lowers the loss of energy by conductor resistance by double the factor which is 4. Engineers who design electricity generation in ships put into consideration the loss of energy during transmission, energy lost due to resistance is dramatically reduced when energy is transmitted at high voltage. Production of energy at the point of generation is done at low-voltage of between 2.4kV and 30kV depending on the unit size. The generating terminal voltage is later stepped up by power-station transformer to a high-voltage between 115Kv and 760 kV AC for long distances transmission. High-voltage results to reduction of current and therefore reduces the loss in conductors in any amount of power. For instance, a voltage rise by a factor 10 will reduce the current by an equivalent factor 10 and as a result reducing the energy loss 100 times as long as the conductors used are of the same size in the two cases. Normally for long-distance transmission, overhead lines of voltage ranging from 115 to 1201kV are used. Transformers are used to reduce voltage to lower levels the energy distributed to residential end commercial users at substations. A combination of 33Kv-115Kv for sub transmission depending on customers requirement and the country and a distribution of between 3.3-25Kv is used to accomplish this distribution. The transformation of energy to low-voltage which is between 100 and 230V is done is done at the point where the energy is to be used. Transmission grid is defined as a network made up of substations, power stations and sub-stations. A three phase alternate current is used by engineers to transmit energy within the grid. A DC system would require conversion equipment whose cost is relatively high and this is only justifiable for specified projects. The distribution of power to the end user is only done using a single-phase AC because it cannot be used for big polyphase-induction-motors. This scenario is different from the early 19th century where two phase transmission was used although it required four wires or three wires which did not have equal currents. In an AC circuit the capacitance and inductance of the phase-conductors is significant. Reactive power constitutes the current flowing in the circuit components and do not transmit any energy to the loads. Extra losses are in the transmission-circuit are caused by the reactive-energy. The ratio real power: apparent power is called power factor. When reactive-power increases, the reactive-power also increases while the power-factor decreases. Systems with low power- factor losses higher energy than systems that have higher power-factor. The method of using high voltage transmission of electricity transmission was first in 1882 where direct current was used though it transmitted only 2.5Kv of energy. Later a Swiss engineer whose name was Rene Thury developed a high voltage direct current transmission and his method was adopted by an Italian company in 1883. A series of connected motor generator was used in this system to generate high voltage. Installation of these motor generators was done from the ground while they were driven by installed-shafts from a prime-mover. The operation of the series was done in constant current-mode, each machine had close to 5000 volts; few of the machines had two commutators meant to reduce voltage on all commutators. This system was able to transmit 630 kV at 15 kV DC for a distance of 140 km. By 1913 fifteen Thury- systems were already in operation, however there were other Thury system in the 1930s that operated at 110 kV DC although rotating-machines required high level maintenance and the loss of energy was so high There were many electromechanical devices tested for the generation of electricity for ships in the 20th century but they had little success. One technique that tried to convert direct-current from high-transmission –voltage to low utilization voltage, was o charge a series of connected batteries then the batteries were to be connected parallel in order to serve distribution-loads. This technique was not so useful due to battery capacities that were not limited, series-and-parallel switching difficulties and inefficiency of the battery charge. Another model for electricity generation was the HVDC 1971 whereby a 150kv mercury-arc-valve was used to convert AC hydro-power voltage to cities that were far from Manitoba-hydro generators. Mercury vapors’ were tested, 13 kv DC line of transmission and were able to convert 45 Hz electricity for serving 60 Hz of load in New York city. This technique was tried in Berlin in the year 1941 where it was designed using 115km transmission network of cables that were buried and using a mercury-arc-valve, however due to the collapse of the German government the year 1945, the project was not completed. The ideal was that the underground cables were less likely to be targeted by bombing during the time of war. The mercury-arc valve was later transferred to Soviet Union for use there. The year 1954 marked the introduction of the full use of mercury-arc valve in the transmission of high voltage for use in commercial services. A high voltage DC was built between the island of Gotland the interior of Sweden. HVDC was identified as having many advantages above the use of AC; this is because of its ability in transmitting big quantities of power for longer distances and for low capital costs. The loss of energy by high voltage transmission was marked to be close to 3.1% in every distance within the ship depending on construction details and the voltage levels. The use of electric shipping system has been tried by a research institute in Korea. During the design of this system many factors that would result from this project were put into focus. The transmission network was made up of single subsystems, power-supply network, catenary system, auto transformer and any other sub systems. The Korean system uses a single-phase power which is at 27.5 kv/55 kV. The overall system is interconnected with a three phase power-system which is to be supplied with a single phase load that is large. The electric-power-utility normally supplies about 154 kV to the electric-shipping system all through the transmission line. The two pairs of single phase-power are found in the connecting transformer. The connection of the transformer is between an adjacent feeder and the catenary and then rails are connected to the central point of the winding. During the early times of electric power which is commercial, electric power transmission which had the same voltage as in lighting and in mechanical loads used to restrict the generating plant and consumer distance. Direct-current was used in electricity generation in the early 1880s although increasing voltage for long distance transmission was not possible. A variety of loads for instance fixed motors, shipping transport and lighting needed voltages of different levels and therefore used multiple generators and different circuits. As a result of this specialization due to transformation that was not efficient, the generators had to be close to their loads. It looked like that era, he electricity industry would grow into a distributed-generation system where big numbers of smaller generators would be located near their loads. The installation of 1KV distribution-system was done in great Barington in the year 1886. That very year, AC power which was at 2 kV, made a 30 km transmission, which was installed at Cerchi, in Italy. During a meeting on May-16, in 1888, a delegate delivered one lecture which was entitled a modern System of AC -Motors and their transformers, demonstrating the apparatus which enabled successful generation and employment of polyphase- alternating-currents. The transformer, in addition to Tesla's -polyphase and single phase induction -motors, were vital for a merged AC distribution-system for both the lighting and the machinery. Ownership of rights to Tesla-patents was a vital advantage to Westinghouse Company for offering complete AC power-system for both the lighting and also power. looked upon as among the most significant electrical-innovations, universal systems used transformers for stepping up voltages from the generators to the high-voltage lines of transmission, and then for stepping down the voltages to local distribution-circuits or to the industrial customers. Using suitable choices of utility frequencies, both lighting/ motor loads could then be served. Rotary-converters and later the mercury arc valves and also other types of rectifier equipments allowed Direct Current to be made available where it was needed. Generation stations and even loads using different kinds of frequencies could then be interconnected by means of some rotary converters. By the use of common plants of generating for all types of loads, vital economies-of-scale were later achieved, lower overall capital-investment was also required, and load-factor on each of the plants was boosted thus allowing for advanced efficiency, and a lower overall cost for the consumers and raised the overall electric power use. By allowing several generating plants be organized over an extensive area, electricity generation cost was made less for use in ships. The most proficient available companies could be in use to provide the variety of loads during a day. Reliability was enhanced and cost of capital investment reduced, since the stand-by production capacity could have been shared across many other customers and in a wide geographical area. Remote and the low energy cost in ships, like hydroelectric-power or the mine mouth coal could be used to reduce energy-production cost. The initial transmission of a three phase AC using high-voltage happened in 1891 when the international electricity exhibition on generation of electricity in ships was held in Frankfurt. A 25kV transmission-line, about 175 km length, connected the Lauffen on Neckar and also Frankfurt. Voltages used in electric-power-transmission in ships increased all the way through 20th century. By 1914, 55 transmission-systems each one working at above 70 kV were in operation. The uppermost voltage then in use was about 150 kV. The rapid growth in industrialization in most parts of the 20th century made electrical- transmission networks and also grids a crucial part of infrastructure in many industrialized nations mostly in Europe. Networks of local the generation plants and also some small networks of distribution were deeply spurred by requirements of the First World War whereby large electricity-generating firms were constructed by most governments to make available power to munitions-factories. Later some of these plants were linked to deliver civil load all the way through long distance transmissions. Conclusion High voltage power generation in ships uses the same concept of the transportation of bulky electricity via transmission network over a long distant. It operates on the principle of transport high voltage electric energy with less current over long distance in order to reduce power loss by the conductors due to resistance. When designing electricity generation in modern ships engineers consider several factors so as to reduce energy loss in the transmission networks, this is achieved by locating generating plants near to the consumer. In designing transmission-networks engineers should consider the network safety, redundancy and also economic factors while at the same time transport the energy efficiently via the transmission networks. There are also factors that affect electricity generation like government policy, which controls the electricity grid produced. During the 19th century many innovations were made in order to come up with the most efficient technique, all these innovations focused on the techniques that are cost effective, reduces energy loss put focus on environmental and health concern. Works cited Grigsby, L. 2001, The Electric Power Engineering Handbook., New York: CRC Press. Pansini, A., 1978, Undergrounding electric lines. New York: Hayden Books. Read More

This is a major principle in electricity generation because there is the risk of the generating plant and the transmitting equipment shutting down if the demand- and- supply factors are not in a balance and this can result to regional black out like the one that occurred in US Northwest and California in 1996. Therefore in order to avoid such cases, electric- transmission-networks are thus interconnected national, regional or continent wide thus ensuring that there is the provision of alternative power flow routes if equipment failure occurs.

The control mechanism so stated will assist in enhancing that the power is kept at a constant in the ship so as to support the internal system. Reduction of energy loss due to the wire resistance is also a major principle in electricity generation. High voltage can be used to reduce this energy loss. Current is proportional to circuit power, while the loss of power in the form of heat in wires has the same proportion with current squared. Since power has the same proportion with voltage, a trade off between high voltage and lower current can occur.

As a result high voltage results to less power loss. Resistance reduction which can achieve through in the conductor diameter can effectively reduce power loss even though large conductors are expensive and heavy to carry. Failure protection is also a major principle in electricity generation which can be avoided through communication. Since high-voltage DC uses long transmission-lines the operators require a communication system that is reliable, this is important for power grid control and also distributing facilities.

Communication between the two ends is important to monitor power flow in-and-out of protected-line section in order that faulty equipment or conductor can be quickly diagnosed and system balance restored. Short circuits in the transmission lines and other faults if not protected can make telecommunication un-reliable. There is need therefore to select a communication system which is reliable like microwaves, power line communication or optical fibers. Transmission lines determine limits the amount of power to be transmitted.

The length of the wire determines this amount; short lines for instance results to conductors heating thus setting the thermal limit. Conductors sag as a result of drawing much current and damage to the equipment due to heat may happen. Ideally, power that flow via an AC line have the same proportion with the phase -angle sine of receiving voltage and the transmitting and. This angle should not tend to be cross to 90 degrees because the angle varies according to the generation and the system loading.

Phase shifting transformers or series capacitors are used to improve stability on most long wires. Distributed-temperature-sensing is used to measure real-time temperature when monitoring the capacity of the capacity of the transmission system. Optic fibers are used to sense temperature in monitoring solution by either integrating them inside a high-voltage cable or mounting them externally on the insulation cable. During electricity generation health consideration is an important factor to put into focus.

Current as result of low power, electromagnetic-radiation poses serious health hazard to the life of human being. It has been found out that people living or those who work near to lines of power are affected by various diseases that do not live near to power lines. Magnetic fields that are above 101 µT have been proven to have acute biological effects to human body. In a home residence there is non limited or carcinogenicity in people leukemia which is associated with some average exposure to some residential power/frequency magnetic fields found in of which are about 0.

11 µT in the northern American and 0.07 µT in Europe. These impacts therefore can have long and short term effects on the life of human beings and should be put into consideration. The authority on electricity generation is exercised by they local authority, they control the grid of electricity generation and ensures that there are put in place disincentives for states to benefit more than them.

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