플라즈마 중합법에 의한 헥사메틸디실록산 박막의 제조와 유전특성

李常熙(Sang-Hee Lee),林應春(Eung-Choon Lim),金旺坤(Wang-Gon Kim),張錫九(Suk-Koo Chang),李德出(Duck-Chool Lee) 대한전기학회 1997 전기학회논문지 Vol.46 No.1

마이크로 프로세서에 의한 Trapezoidal 구동형 직류 무정류자 전동기의 콘트롤러 설계

장석구 大田工業大學 1989 한밭대학교 논문집 Vol.6 No.2

ABSTRACT The trapezoidal drive DC brushless motor has the merits of high power rate and low cost over the sinusoidal drive one. The controller of trapezoidal drive DC brushless motor consists of the converter, in which the firing angle of SCR is controlled by the microprocessor, and the Inver- ter, in which the driving pulse are generated by the revolving shutter. This paper presents the microprocessor-based controller design which has the merits of high precision control, flexibility, and stability. The trapezoidal drive DC brushless motor has the merits of high power rate and low cost over the sinusoidal drive one. The controller of trapezoidal drive DC brushless motor consists of the converter, in which the firing angle of SCR is controlled by the microprocessor, and the Inverter, in which the driving pulse are generated by the revolving shutter. This paper presents the microprocessor-based controller design which has the merits of high precision control, flexibility, and stability.

변압기의 1차측 차단 시뮬레이션

張錫九 大田産業大學校 1995 한밭대학교 논문집 Vol.12 No.1

The loss of the electrical power for the transformer using in the consumer can be obviously reduced if the primary of transformer breaking in no load state. In order to breaking the primary of transformer, the transient phenomena coming out the secondary of transformer should be precisely analysed, and the following system for the mechanism must be protected from the surge due to breaking the primary of transformer. In this paper using the PSPICE program, when the primary of transformer breaking, the transient phenomenon for the secondary of the transformer was simulated and analysed according to that result.

공장자동화 적용을 위한 페트리네트의 하드웨어 실현

柳昶根,張錫九 大田工業大學 1991 한밭대학교 논문집 Vol.8 No.1

Petri net are an abstract system description formalism that can be used in serveral field, such as performance evaluation, communication protocols, control systems, multiprocessor and data flow computer architecture and fault tolerance. The goal of this paper is to achieve a method of realizing logic controllers from the petri net in factory automation. This approach of controller synthesis assigns a D flip-flop for each state in the petri net, and then logic to represent the state. This becomes a typical two level AND-OR gate logic.

變壓器 1次側 遮斷에 의한 損失節減에 관한 硏究

張錫九 大田産業大學校 1996 한밭대학교 논문집 Vol.13 No.0201

Transformer is an indispensible energy converter for the proper voltage supply to a load and it is installed and operated very widely. When the single load has low load factor and high capacity with long term no load operating time, there is a large amount of energy loss generated in the transformer itself due to the operation during the no load condition. In this paper automatic circuit breaking system is configured for the purpose of minimizing the no load loss of the transformer. Under the no load condition, the input stage of the transformer is automatically cut off and the power is supplied by the auxilliary transformer to make the output stage always powered. The experimental result showed that one unit of 1,000(KVA) transformer with 20% of operating interval saved 41,672(KWH) of total power amount to \2,416,000 of annual total cost for operation. For the protection and the safety of the transformer, following security apparatus and sequences are designed and installed. 1. Surge absorber is installed at the input stage to protect the transformer from the voltage surge arising from a cut off at the high voltage side. 2. Load is made to be connected with 1 second delayed, a sufficient time for the stabilization of the output stage, after the input stage is switched-on. 3. To avoid the frequent operation by the intermittent load, the circuit breaker is operated only if the no load signal is sustained for more than 10 seconds, which is determined to be the true no load condition.

폴리머碍子의 自然劣化現狀에 關한 硏究

張善奉,張錫九,沈在明 大田産業大學校 2000 한밭대학교 논문집 Vol.17 No.1

In this paper, for the estimation of its long-term reliability, we took polymer insulators used at the seashore during about 2 or 4 years. it used a variety of methods to understand deterioration characteristics for these polymer insulators. For investigating the degree to change inherent characteristics, we performed electrical flashover voltage test, leakage current measurement. and for examining surface properties of its materials, we utilized SEM. FTIR-ATR and contact angle meter. These test results had been compared virgin ones with aged samples in the field. In the electrical flashover test with all samples, although it had a slight reduction. the flashover voltages was in the boundary of KS criteria. The results showed that the contact angles of aged sample surfaces were larger than that of virgin ones. however, sample B which had a short experience in the field showed contact angle to be reduced. Because of the environmental impact on polymer insulators, exposed for many years under natural conditions. it was verified the insulator material at the surface of the insulators undergoes a slight degradation process as the micro cracks at the inspection utilizing SEM. In conclusion, the polymer insulators aged during 2 or 4 years under our national environment showed agreeable performance. For exactly evaluating its long-term performance, we need to cumulate data that was the results to analyzing characteristics on polymer insulators.

역률 개선 장치를 이용한 마이크로프로세서의 교육적 활용방안

정태선,장석구,심재명 大田産業大學校 2002 한밭대학교 논문집 Vol.19 No.-

As increasing the power demands, we can take the advantage in reduction of power loss, voltage drop, loss of transformers and distribution line, while we use reasonably the energy which is limited by the insufficient supply of energy resources and the high power rates. So industrial field is increasing the facilities of capacitor bank for active power and the reduction of the power loss. This paper improve the working domain by searching the optimal value of Xc in load circuit, as detecting different between voltage phase and current phase which is supplied to load by using PT and CT. Also, this paper can aid learners understand easy Power factor measurement and improving method by using phase relation between voltage and current, compose method of capacitor bank, and processor on the educational field.

까치에 의하여 發生하는 配電線路의 故障豫防에 관한 硏究

전시식,장석구,심재명 한밭대학교 2004 한밭대학교 논문집 Vol.21 No.-

In modern times, electricity is an essential energy and its dependence to people is more increased. The distribution line system in Korea consists of 22.9kV multi-ground connection. The 15.2% of distribution line troubles is being produced by birds' contact with distribution line. The cause of the interruption of electric power is mostly a magpie. To prevent the troubles by magpie, various kinds of prevention measures have been tried for 20 years. But the trouble continues to be happened by magpie's outstanding ability of learning. In this paper, the effectiveness of prevention equipments using a sense of touch, sight and hearing which have been used at Korean Electric Power Corporation is analyzed and more effective prevention measures is considered. As a results, to prevent the troubles, it is difficult to get good effectiveness when only one prevention measure is applied. However, when several measures are applied at the same time, the troubles can be reduced. Also, even though magpies build their nests, for not to make the troubles, a electric pole equipment should be corrected and its form should be improved. In addition, we have found the facts that the activity periods for moderating the number of magpie and for removing the nests, weather, and DB system are simultaneously considered as the effective prevention measures.

소형 풍력발전시스템을 위한 계통연계형 인버터에 관한 연구

李大東,沈在明,張錫九 한밭대학교 2004 한밭대학교 논문집 Vol.21 No.-

We imported technology from abroad and studied grid connected type wind power generation owing to the lack of technology, but nowadays we conduct researches in many quarters because of national supporting policy. However, the research speed is delayed by burden for research expense which wind power generation is huge. Therefore, in order to experiment on various kinds of the wind turbine, generator, and converter easily, the development of wind power system is demanded powerfully among research workers. In this paper, in order to satisfy this need, I suppose a new simulation development environment. The electric power generated by wind is changing, so by using the converter, schedule electric power must be provided. Therefore, in this paper, I explained an element of the converter of the wind power generation system by showing two examples. First, Diode rectifier and current controlled voltage source inverter by using IGBT(Insulated Gate Bipolar Transistor) element was used in the wind power generation system. Second, rectifier for control by using IGBT and current controlled voltage source inverter by using IGBT element was connected the grid. Simulation for two examples of grid connected type wind power generation system uses PSCAD/EMTDC and analyzed the result.

콘덴서제조공장의 전력부하설비의 고조파에 관한 연구

김득중,심재명,장석구 大田産業大學校 2002 한밭대학교 논문집 Vol.19 No.-

Lately power semiconductors such as thyristor devices is widely used in electric power load installation. The use power semiconductors is easy to be a major cause of harmonics generation. In this paper, voltage and current harmonics is to be mesured in twenty places which is selected from power receiving board of the capacitor mannufactory. The results is analysised by experimental observation. According to the analysis contents, total voltage harmonics occured in the 22.9kv y-connection is to be proved within harmonics international standard but current harmonics was approached to standard upper limits line. The harmonics incoming through the distribution line by harmonics of the near factory is measured at the measurement factory. In this paper, the countermeasure to decrease harmonics generation quantity is considered through the theoretical survey.