• Title/Summary/Keyword: Power farm

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Hematological Characteristics of Olive Flounder (Paralichthys olivaceus) in Culture Farm Influenced by Heated Effluent Water from a Power Plant in Summer (여름철 온배수 수역에 인접한 양식장 넙치(Paralichthys olivaceus)의 혈액 성상)

  • Chang, Young-Jin;Hur, Jun-Wook;Chin, Pyung
    • Journal of Aquaculture
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    • v.15 no.4
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    • pp.267-273
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    • 2002
  • Effect of heated water from a power plant in summer on hematological characteristics of flounder (Paralichthys olivaceus) were investigated. Hematocrit level fluctuated between 15.7 and 16.3% in control farm, but it significantly increased to 17.7% in the high-WT farm. The corresponding values for hemoglobin concentration were 9.9~18.0 $g/㎗$ for the control farm and 6.2~19.4 $g/㎗$ for the exposed farm. The plasma cortisol remained between 0.6 and 2.8 ng/$ml$ in the former but significantly decreased 317.1 to 3.3 ng/$ml$ in the later. The plasma glucose also decreased from 36.5~46.0 to 23.5~36.5 mg/$dl$. Plasma osmolality decreased from 551.5~597.0 to 391.0~466.5 mOsm/kg.

Dynamic Analysis of Variable Speed Wind Power Systems with Doubly-Fed Induction Generators (이중여자 유도발전기에 의한 가변속 풍력 발전시스템의 동특성 해석)

  • Choi, Jang-Young;Jang, Seok-Myeong
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.55 no.6
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    • pp.325-336
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    • 2006
  • This paper deals with the dynamic analysis of variable speed wind power systems with doubly-fed induction generators (DFIG). First, the mathematical modeling of wind farm which consists of turbine rotor, DFIG, rotor side and grid side converter and control systems is presented. In particular, the equation for dynamic modeling of the DFIG and the AC/DC/AC converter is expressed as dq reference frame. And then, on the basis of mathematical modeling for each component of wind farm, dynamic simulation algorithms for speed and pitch angle control of wind turbine and generated active and reactive power control of the DFIG and the AC/DC/AC converter are established. Finally, Using the MATLAB/SIMULINK, this paper presents dynamic simulation model for 6MW wind power generation systems with the DFIG considering distribution systems and performs the dynamic analysis of wind power systems in steady state. Moreover, this paper also presents the dynamic performance for the case when the voltage sag in grid source and phase fault in bus are occurred.

Analysis of Determining Factors for Power Size of a Tractor (트랙터의 출력수준 결정에 영향을 미치는 요인 분석)

  • Kim, Byoung-Gap;Lee, Won-Ok;Shin, Seung-Yeop;Kim, Hyeong-Kwon;Kang, Chang-Ho;Rhee, Joong-Yong
    • Journal of Biosystems Engineering
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    • v.34 no.1
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    • pp.8-14
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    • 2009
  • When a farmer buys a tractor, the power size of a tractor is determined by various factors such as farm size, farmer's age, farming type, topographical area of farm. Relationships between tractor selection and these factors were found. Three regression models were developed to analyze the relationship. Those models were an OLS-1 model (based on 567 samples having tractors), an OLS-2 model, and a Tobit model (both based on the 1,941 samples). Regression analysis results showed that farm size and farmer's age affected selection of power size for all models at an 1% significance level. It was also shown that some farming types also had significant relationships with the tractor power size. Upland cultivating farmers and livestock farmers had larger tractors than rice cultivating farmers, while orchard farmers had smaller tractors. As for the topographical area, only middle area had significant difference with plain area. Farmers who had a rice-transplanter or a combine had larger tractors than those who didn't.

A study on comparing short-term wind power prediction models in Gunsan wind farm (군산풍력발전단지의 풍력발전량 단기예측모형 비교에 관한 연구)

  • Lee, Yung-Seop;Kim, Jin;Jang, Moon-Seok;Kim, Hyun-Goo
    • Journal of the Korean Data and Information Science Society
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    • v.24 no.3
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    • pp.585-592
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    • 2013
  • As the needs for alternative energy and renewable energy increase, there has been a lot of investment in developing wind energy, which does not cause air pollution nor the greenhouse gas effect. Wind energy is an environment friendly energy that is unlimited in its resources and is possible to be produced wherever the wind blows. However, since wind energy heavily relies on wind that has unreliable characteristics, it may be difficult to have efficient energy transmissions. For this reason, an important factor in wind energy forecasting is the estimation of available wind power. In this study, Gunsan wind farm data was used to compare ARMA model to neural network model to analyze for more accurate prediction of wind power generation. As a result, the neural network model was better than the ARMA model in the accuracy of the wind power predictions.

Survey on the Regular Maintenance of Agricultural Machinery for the Full-Time Farmers (전업농가의 농업기계 정기 점검정비 실태조사)

  • 이성범;이종환;이운룡;강지원
    • Journal of Biosystems Engineering
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    • v.26 no.4
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    • pp.323-330
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    • 2001
  • The regular maintenance and repair status of major farm machinery such as power tiller, farm tractor, rice transplanter and combine harvester etc., were surveyed and analyzed for the full-time farmers in order to get basic information for promoting farm machinery productivity. The survey was carried out through 209 farmers from 9 provinces. The results of this study can be summarized as follows; 1. The regular maintenance of farm machinery was conducted at repair shop(49.5%) or dealer agency(12.0%), and also conducted by farmers at their house(34.9%). 2. For the status on the cleanness or exchange times of engine oil, fuel filter and air cleaner, most farmers conducted fewer times than the necessary times. And, 5.3%, 7.7%, and 2.9% of surveyed farmers experienced breakdowns due to the insufficient cleanness or exchange oil, fuel filer, and air cleaner, respectively. 3. Most farmers(76.1%) recognized the necessity of farm machinery training or education, and they preferred one week for the training period, simple or easy maintenance for the training level, agricultural technical center or farm machinery manufacturer for the training agency. 4. Complete recognition of operation manual and sufficient maintenance before-, during-, and after-operation for the farm machinery can minimize the breakdowns, enlarge the endurance prevent the safety accidents, and promote productivity of farm machinery. And, these can be accomplished by the thorough training or education for agricultural machinery.

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On Study of the Effects of External Forces on the Fish Farm Structure Due to Following Flows and Currents in Fully Operated Ship's Propeller (선박 프로펠러 후류 및 조류에 의해 발생한 힘이 가두리 양식장 구조물에 미치는 영향에 관한 연구)

  • Lee, Kwi-Joo;Ra, Young-Kon;Kim, Kyoung-Hwa;Ryu, Tae-Ho
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2002.10a
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    • pp.245-250
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    • 2002
  • This report describes the effects of following flaws due to ship's propeller on the fish farm structure when the ship's propeller is operated in full power. This study is applied an incompressible newtonian fluid theory, which is governed the Navier-Stokes equation. For the numerical solution, Neumann equation are applied as the boundary conditions. The result shows that the flow velocity near the fish farm is 1.0 m/sec. The actual measurement carries out by using propeller type velocimeter in order to measure the velocity of following flows and currents around the fish farm area. The result shows that the maximum velocity near the fish farm structure is 1.2 m/sec in depth of 1.5 m. This velocity is used for calculation of external force on the fish farm structure. The results of structural strength of the fish farm structures show that the actual maximum bending moment and bending stress are less than the damage strength of material. So the fish farm structure is not affected by the following flows and currents of ship's propeller.

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The Research on Snowball in by John Halas and Joe Batchelor (존 할라스와 조이 베첼러의 <동물농장>에서 스노볼에 대한 연구)

  • Yun, Young-Seok
    • Cartoon and Animation Studies
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    • s.36
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    • pp.19-44
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    • 2014
  • is an animation by John Halas and Joy Batchelor, based on Animal Farm by George Orwell, screened in England, 1954. by John Halas and Joy Batchelor showed true occasions in history, such begins with Bolshevik Revolution which broke out in October of 1917, through new economic policy called NEP, monopolization of power by Stalin, and Moscow Justice as a fable. in positioned real people from Bolshevik revolution as characters as in allegory, due to its fable-nature. However, descriptions in by John Halas and Joy Batchelor differs with by George Orwell from the middle of its story. In by John Halas and John Batchelor, Snowball is killed by Napoleon, unlike in by George Orwell, which Snowball is thrown out by Napoleon. showed Stalin as Napoleon, and Trotsky as Snowball in its characters. Satire description on Stalin's reign of terrorism after Bolshevik Revolution was same in both by George Orwell and by John Halas and Joy Batchelor; however, the view on Trotsky was different with each other. Therefore, this paper is written to describe allegorical factors of Bolshevik Revolution in by John Halas and Joy Batchelor, as well as to reinterpret the value of Trotsky and Russian Revolution by researching Snowball in .

Analysis of the Utilization Characteristics of Electrical Power and Equipments on the Farms (농촌의 전력및 전기기기의 이용특성분석)

  • 박승우;류한열
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.17 no.4
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    • pp.3943-3955
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    • 1975
  • The purposes of this study are to evaluate the utilization characteristics of electrical power consumption, to grasp the present trends in the use of electrical equipments, to estimate the demand factor and load factor being held, and to evaluate the efficiency of electical uses for the recently electrified farms cultivating paddy rice. For the purposes, 109 sample farms located in eleven villiages electrified in six different years from 1968 to 1973, were chosen at random and investigated on 35 items concerning to electrical uses and wiring systems. The survey was carried out in 1975, in the vinicity of Suweon city. The results are summarized as follows: i) The average annual power consumption on sample farms is considered to be low, being 242.9 Kwh. in 1974, and varied according to the different electrified year and size of cultivated land, respectively. It has significant positive correlation to the area of farm, too. ii) Between the number of year of electrical uses and the power consumption, there is very significant positive correlation, which could be expressed as Y=43.041+16.108 X, where X represents the number of years of electrical uses. The annual increment of power consumption is much greater at the beginning of the electrification than that at the later years, its average being approximately 20 percent. However, it is recommended that any estimation of long-term increments should be carefully investigated. iii) The monthly power consumption varies considerably throughout a year, in which the heaviest farm load occurs in November. Observing the seasonal variation of consumption, the winter-time is the heaviest season while the summer is the lowest. The result implies house lighting is chief contribution to the present electrical consumption on the farms. Comparing the variation of monthly consumption ratios between the sample farms and industries, the electrical uses on the farms are independant of the industrial uses, and further, the agricultural uses are of inverse pattern to the farms from the results that there is negative correlationship between them, iv) The number of electrical equipments used on the farms are occupied chiefly by lighting sources. Next to the lighting sources, household appliances of small quantity and some motors are used. The mean electrical quantity is about 1, 127.4 watt, which corresponds to about 37.6 per cent to the contracted quantity. The composition of quantity is chiefly occupied by the electrical motor of about 1.5 hp., single-phased. The number of the annual utilization hours of each equipment is tabulated in Table IV-5. In contradiction to the high utilization of lighting sources and small household appliances, the motor is poorly used for approximately 22 hours in a year. v) More than 55 per cent of farms want to purchase new electrical equipments such as small household appliances and electrical motors in their number. The impulse of purchasing such items is stimulated by the contacts to the mass media and their knowledge on such equipments. Consequently, the increase of electrical uses could be prompted by such trials as education and demonstration. vi) The demand and load factors on the farms vary considerably according to the greater variation of the power consumption, daily or monthly. The daily demand factor is 22.4 per cent and load factor 18.6 per cent, while the annual demand factor is 1.3 per cent and load factor 70 per cent approximately. Therefore, the low efficiency of construction cost requires re-evaluation of the present contracted quantity of 3 Kw. or increase of electrical uses. vii) The electrical energy on the farms devoted chiefly to lighten the farm residences does not contribute to the farm incomes. Consequently, the cost of electrical consumption presses considerably upon the farm economy. Therefore, there is great need to build up the electrical uses on the farms through the development of new works and techinques to utilize any electrical equipments on the production of farm products. Further more, such the development should be related to increase the actual income of the farm consumers.

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Selection of Promising Wind Farm Sites and Prediction of Annual Energy Production of a Wind Turbine for Eight Islands in Korea (국내 8개 도서지역 대상 풍력발전 유망후보지 선정 및 발전량 예측)

  • Kim, Chan-Jong;Song, Yuan;Paek, Insu
    • Journal of the Korean Solar Energy Society
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    • v.37 no.6
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    • pp.13-24
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    • 2017
  • Finding promising wind farm sites in islands of Korea is performed in this study. Total ten islands that have been measuring wind speed and direction using automatic weather stations for at least ten years were subjects of this study. Conditions for finding suitable wind farm sites including wind resource and various exclusion factors were applied and two islands that were found not to be suitable for wind farms were excluded. Micositing of a single wind turbine for the remaining eight islands was performed to estimate the annual energy production and the capacity factor.. Based on the simulation results, the wind farm sites selected within the eight islands were found to be suitable for wind power. The capacity factors were varied between 22.3% and 33.0% for a 100 kW wind turbine having a hub height of 30 m.

A Study on the Improved Protective Relaying Algorithm Applied in the Linked System Interconnecting Wind Farm with the Utilities (풍력발전단지 연계 전용선로 보호계전방식의 향상에 대한 연구)

  • 장성일;김광호;권혁완;김대영;권혁진
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.52 no.12
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    • pp.675-683
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    • 2003
  • This paper describes the correction strategy of an overcurrent relay applied in the linked line for interconnecting wind farm with utility power networks in order to improve the capability of a fault detection. The fault current measured in a relaying point might vary according to the fault conditions. Generally, the current of the line to line fault or the line to ground fault in the linked line is much higher than the set value of protective relay due to the large fault level. However, when the high impedance fault occurs in the linked line, we can't detect it by conventional set value because its fault level may be lower than the generating capacity of wind farm. And, the protective relay with conventional set value may generate a trip signal for the insertion of wind turbine generators due to the large transient characteristics. In order to solve above problems and improve protective relaying algorithms applied in the linked line, we propose a new correction strategy of the protective relay in the linked line. The presented method can detect the high impedance fault which can't be detected by conventional relay set value and may prevent the mis-operation of protective relay caused by the insertion of wind farm.