- 學位論文
應用變壓器湧流與故障電流即時辨識技術於電力變壓器保護系統
Protective System of Power Transformers Applying Inrush and Fault Current Real-Time Identification Technology
摘要
電力變壓器保護系統之信賴性包括可靠度與安全度。當電力系統發生故障等不能忍受之擾動時，保護電驛需對自己保護區間內之故障，應迅速、正確的反應動作，謂之可靠度；對於鄰近區間之故障，則應保持不動作以縮小停電範圍，謂之安全度。本論文針對差動保護裝置為變壓器主要保護設備之一，其基本原理早已成熟，該保護裝置最關鍵和最困難的問題是在於如何防止激磁湧流所導致差動保護裝置的誤動作，對此提出激磁湧流判別對策。 如何可靠的區分激磁湧流與故障電流，本文採用衝擊響應頻譜(SRS)分析方法來辨識激磁湧流，通過Matlab軟體運算SRS並且加以處理，提取激磁湧流特性，可以發現SRS分析方法能夠可靠地判別激磁湧流，並且實際運用到可程式系統單晶片(dsPIC)以及週邊設備，實現即時判別之效果。 並且應用即時辨識技術於電力潮流分析軟體ASPAN，模擬變壓器及系統各種故障電流狀況對電力系統負載調度影響以提供電力供電的穩定度；並分析用戶全年平均恢復供電時間(System Average Interruption Duration Index ，SAIDI)與全年平均恢復供電次數(System Average Interruption Frequency Index ，SAIFI)強化此辨識技術對用戶供電的可靠度，同時證明本論文不僅符合電力系統保護電路的需求更具研究的效益。
並列摘要
A credible protection system for a power transformer includes both of the reliability and safety. Reliability means that the schemed protection zone in a protection system will promptly and accurately respond to an intolerable disturbance due to a power failure in the power grid. While safety means that it won’t respond to any power failure beyond its own protection zone which could otherwise results in an unlimited area of blackout. The principle of differential protection device for power transformer has long been developed. This paper aims at the know-how of how to prevent a differential protection device from malfunctioning caused by the magnetized inrush current. Then a counter measure is presented on how to discriminate and judge the magnetized inrush current. Firstly , we use the technique of Shock Response Spectrum (SRS) to analyze and identify the magnetized inrush current. In addition to compute SRS with Matlab S/W , we then can pinpoint the characteristics of magnetized inrush current. Further , with which , we found out the analysis of SRS is credible for discriminating the magnetized inrush current. Moreover , it is practicable to be burned in a programmable chip (ds PIC ) or other peripheral equipments which leads to a real time and effective way of discrimination. Finally , in order to promote the reliability of power supply , we incorporate the technique with the s/w Matlab to simulate the varieties of fault currents and its influence of power load dispatching. As in whole , by analyzing the index of SAIDI ( System Average Interruption Duration Index ) and SAIFI ( System Average Interruption Frequency Index ) , we see the efficiency and strength of this research which not only contribute to the reliability of power supply but also coincide the demand of protection system.