จำนวน Repository ( 255 )

การวิเคราะห์แรงดันตกชั่วขณะเมื่อมีการติดตั้งแหล่งผลิตไฟฟ้าแบบกระจายตัวในระบบจำหน่าย
การวิเคราะห์แรงดันตกชั่วขณะเมื่อมีการติดตั้งแหล่งผลิตไฟฟ้าแบบกระจายตัวในระบบจำหน่าย

This research presents an Analysis of Voltage Sags on the Installation of Distributed Generation in the Distribution System. The computer program PSCAD/EMTDC (Power Systems Computer Aided Design / Electromagnetic Transient in DC system) version 4.2 is applied to provide electrical parameters for the modeling and simulation and to analyze the fault occurred which resulted in voltage sag. Test results from PSCAD/EMTDC show the values of voltage sag when 5 types of fault are occurred (Single Line to Ground Fault Double Line to Ground Fault Three Phase to Ground Fault Line to Line Fault and Three Phase Fault). For all cases the value of root mean square voltage before fault is 100% or 1.0 pu. It can be seen that for both radial line and closed circuit when DG are installed in the system the value of phase to ground RMS residual voltage and phase to phase RMS residual voltage at the bus of Bang-pa-in 2 substation are more than the values in case of the system without DG.

2561
A simple method of system response compensation of a near infrared instrument for determining brix value of peaches
A simple method of system response compensation of a near infrared instrument for determining brix value of peaches

A system response of a near infrared (NIR) instrument sometimes changes depending on measuring conditions such as warming up time room temperature and the others. In the last peach experiment we measured NIR spectra over 3 days and spectral differences were observed between spectra measured at the first day and those at the second and third days. Therefore a simple method of system response compensation was examined. As a result of principle component analysis (PCA) of second derivative (2D) spectra of peaches samples were separated into two groups the first-day measured samples and the second and third-day measured ones on the plane consisted of PC1 and PC2. On the hypothesis that average 2D spectrum of each group should be almost the same the difference of the average 2D spectra (2D spectrum) was calculated. Using 2D spectrum 2D spectra of the first-day samples were adjusted to those of the other samples. The data set including the adjusted one is called “compensated 2D data set” hereafter as compared with “original 2D data set”. As results of partial least square (PLS) regressions based on the original and compensated 2D data sets and Brix value of peaches good SEPs of 0.98 °Brix for both cases could be obtained. The number of factors for the calibration model in case of compensated 2D data set was smaller than that in case of original one. It was concluded that the method using 2D spectrum could be used to compensate the difference of system response of an NIR instrument.

2560
รูปแบบการระบายความร้อนด้วยน้ำที่ส่งผลต่อสัมประสิทธิ์สมรรถนะของระบบปรับอากาศแบบแยกส่วน
รูปแบบการระบายความร้อนด้วยน้ำที่ส่งผลต่อสัมประสิทธิ์สมรรถนะของระบบปรับอากาศแบบแยกส่วน

The purpose of this research was to investigate cooling water profile that effect to coefficient of performance of spilt type air- conditioning system. Air conditioner size of 12000 Btu/h was used in this experiment. There are three experiment of cooling water profiles in this work such as water spray water drop and heat exchanger profile. The ambient temperature conditions were controlled at 35 40 43 and 45 oC. The results of this study were found that heat exchanger profile had the highest average coefficient of performance and energy efficiency as 4.94 and 9.15 Btu/Wh which increased as 20.1% and 8.47% respectively when comparing with the normal working.

2560
การติดตั้งแหล่งผลิตไฟฟ้าแบบกระจายตัวเพื่อเพิ่มความเชื่อถือได้ในระบบจำหน่ายไฟฟ้า
การติดตั้งแหล่งผลิตไฟฟ้าแบบกระจายตัวเพื่อเพิ่มความเชื่อถือได้ในระบบจำหน่ายไฟฟ้า

This paper presents reliability evaluation in distribution system with distributed generation. The main objective is to minimize the customer interruption cost subject to given number of distributed generation. The minimization problem for customer interruption cost in solved by the developed tabu search algorithm together with reliability worth analysis that provide an indirect measure for cost implication associated with power outages. The developed methodology is tested with a distribution system of Roy Billinton Test System (RBTS) bus 2 consist of 15 buses and 22 load points. Numerical results from the tests demonstrate that the optimal distributed generation placement can be used to promote reliability of the distribution systems.

2560
การหาค่าพารามิเตอร์ของตัวควบคุมแบบสัดส่วนบวกอินทิกรัลแบบ อัตโนมัติด้วยขั้นตอนวิธีเชิงพันธุกรรมสำหรับระบบการขับเคลื่อนมอเตอร์ซิงโครนัสชนิดแม่เหล็กถาวร
การหาค่าพารามิเตอร์ของตัวควบคุมแบบสัดส่วนบวกอินทิกรัลแบบ อัตโนมัติด้วยขั้นตอนวิธีเชิงพันธุกรรมสำหรับระบบการขับเคลื่อนมอเตอร์ซิงโครนัสชนิดแม่เหล็กถาวร

Proportional plus integral controller has been widely used in permanent magnet synchronous motor (PMSM) drive system due to its simple structure while achieving zero steady-state error. However finding out the optimal parameters of the controller is not an easy task. For this reason this paper presents an automated optimization of proportional plus integral controller for permanent magnet synchronous motor drive system using genetic algorithms. Simulation and experimental results verify the effectiveness than ones of the trial and error method.

2560