การประมาณสถานะของระบบไฟฟ้ากำลังที่มีการพิจารณาสถานะความร้อนของสายส่งและหม้อแปลงกำลัง
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Date
2024
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มหาวิทยาลัยพะเยา
Abstract
The problem of the voltage stability assessment considering the thermal limit of the transmission line has been addressed in this dissertation. Two indicators, namely line voltage stability and line ampacity indices, to determine the voltage stability states and line security of power systems under various operating conditions have been proposed. Both indices rely on the measured values that are already obtained from conventional measurements used in power systems. The identification of weak buses and critical lines based on the proposed indices is possible using only voltage magnitude and real power measurements. Numerical experimental results on two power networks have been tested under increasing system loading and line outage conditions indicate that by considering both line voltage stability and line ampacity indices, power systems could mitigate the risks of voltage collapse and excessive current in transmission lines. The influence of the thermal states of the transmission line and the power transformer on state estimation of electric power systems has also been studied. The three - phase state estimation algorithm based on the weighted least square method has also been proposed. The node admittance matrix model of the three - phase transformer and the weather - dependent thermal model of the overhead transmission line are integrated into the state estimation problem. It is then formulated as a nonlinear optimization with equality and inequality constraints. The estimated state variables consist of the bus voltage phasors, the transformer parameters, the transmission line conductor temperatures, and the weather states. Then, the top - oil and the hot - spot winding temperatures of the transformers can be evaluated using the estimates states. The IEEE 30 - bus and 118 - bus systems have been modified as three - phase test systems and the numerical results indicate that the proposed state estimation can be used to estimate the thermal states of the transmission line and the power transformers, and the accuracy of the estimated states is also improved.
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Keywords
States estimation, Conductor temperature, Transformer parameters, Top - oil temperature, Hot - spot, Winding temperature, Three - phase networks
Citation
ดำรงศักดิ์ วงศ์ตา. (2567). การประมาณสถานะของระบบไฟฟ้ากำลังที่มีการพิจารณาสถานะความร้อนของสายส่งและหม้อแปลงกำลัง. [วิทยานิพนธ์ปริญญาดุษฎีบัณฑิต, มหาวิทยาลัยพะเยา]. ฐานข้อมูลคลังปัญญาดิจิทัล มหาวิทยาลัยพะเยา (UP Digital Collections: UPDC).