This paper deals with the basic concept of tap changing of transformer, types of tap changer and various voltage control methods used for On-load tap changing transformer in distribution network. These methods depend upon the series and parallel operation of On Load Tap Changing Transformer. In parallel operation-automatic voltage controller and low drop compensation controller are used. While in series operation grading time and communication based voltage control methods are used.
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This research paper develops an improved model for assessment of hot spot temperature from the IEEE top-oil rise temperature model by considering the ambient temperature at the first-order characterization using appropriate mathematical notations. The ambient temperature, top oil rise over temperature and winding hot spot rise over temperature were used as input parameters for the development of the improved hot spot temperature model by considering the final temperature state since the time-rate-of change in top-oil temperature is driven by the difference between the exits top-oil temperature for ambient temperature variation. The improved model was then implemented in MATLAB to compute the hot spot temperature for 24-hour load cycle. The result of the improved model shows that the least and highest value of the hot spot temperature are 630C and 105.40C respectively indicating a retardation in the aging process of the transformers. The improved model helps to minimize the risk of failure and to extend the life span of transformers thereby controlling the hot spot temperature rise and top oil temperature.
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This research paper presents the impact of SAIDI threshold on the reliability assessment of electrical power distribution system. Data were collected from ten selected feeders of Ibadan distribution system for a period of five years. The daily SAIDI, natural logarithm of SAIDI, the log-average of SAIDI and the standard derivation of the logarithm of SAIDI were used as input parameters in the development of SAIDI threshold model. The result of the research paper shows that the SAIDI threshold values fluctuate over the years with the least and highest SAIDI threshold values as 2.11596 and 4.62518 respectively which were recorded in the months of September and April. The SAIDI thresholds in the months of January, February, March, April, May and June are 3.18318, 3.32458, 4.22242, 4.62518, 2.71360 and 3.27760 respectively suggesting an indefinite pattern in the SAIDI threshold as a result of unexpected interruptions experienced by customers attached to the distribution feeders. SAIDI threshold forms a basis for power system planning and maintenance strategies.
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In this paper data driven clock gating and look ahead clock gating with modified design is done in the cadence virtuoso tool to obtain the very low power,low noise response,lesser delay,lesser bandwidth and efficient reliability in the electronic devices.The power consumption detail is obtained accurately in the cadence virtuoso power calculator window and also the noise response is also calculated using the same calculator window.The DC response analysis is also obtained for the modified design.
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The entangled nature of various continuous production processes, such as chemical processing, oil and gas, and water treatment, continue to require the advanced process control capabilities of the Distributed control system (DCS) in order to aggregate and analyse a large amount of data at the same instant of time. This paper aims to enhance the flexibility in controlling and monitoring of distillation column by configuring and developing a HMI using DCS with SCADA. DCS provides high scalability, solutions to complexity, redundancy, high adaptability to frequent process changes, hybridized to incorporate PLCs and PCs to control complex functions and to provide reporting services. Hence the optimized control of distillation column has been achieved via DCS.
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Author have gone through a detailed literature review, after the research it was found that among the various available techniques to design multiband patch antenna, proximity coupled technique was found more suitable and efficient to design a multiband antenna. This simulated antenna is a three-band antenna which has the capability to operate at three distinguished frequencies. This proposed design of proximity coupled technique has comb like structure contains no defected ground, a pentagonal shaped patch and a meandered feed, which is designed to connect a SMA connector. Designed antenna is a 3-layer device having higher radiation intensity at 3.18, 4.36 and 5.18GHz.
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