基於同步相量量測值之雙端與三端多區段複合線徑輸電線路故障定位演算法研究

Abstract

本論文針對諸多地下電纜與架空線路混合、多種線徑架空線路，以及多種線徑地下電纜線路所組成之雙端點與三端點多區段複合線徑型輸電線架構提出了以同步相量量測為基礎的故障定位演算法，其中同步相量量測值來源分別為以全球衛星定位系統(Global Positioning System, GPS)為基礎之相量量測單元(Phasor Measurement Units, PMUs)、內建PMUs之數位電驛資料，以及經由電驛量測訊號之非同步校準演算法等。本論文之研究目的首重於解決目前在文獻中各種所被提出的方法皆尚且無法完全處理此類型多區段複合線徑線路架構的故障定位問題。 本論文的研究理論是基於單一線徑兩端輸電線路故障定位技術進一步延伸到兩端及三端多區段複合輸電線路的故障定位演算法設計。利用本論文所提出的演算法，包含故障分支線段選擇器、故障區段選擇器，以及故障定位器之搭配組合，則不僅對於兩端點及三端點複合輸電線路可輕易地識別出內外部故障以及故障區段，更有能力進一步地定位出不論是發生於架空線路或者地下電纜線路事故的正確故障位置。 本論文所提出之故障定位方法擁有嚴謹的理論基礎，且由於不會受到故障型態、電源阻抗，以及負載大小等影響，再加上不需進行疊代計算的優點，因此本方法能夠直接地、簡單地求出故障位置的精確解，並且有效地降低了數學運算的複雜度。不論是模擬驗證還是實際輸電線路事故測試，皆一致地證明了本演算法的效能。所提出的演算法已經自西元2008年起實際運用在台灣345 kV以及161 kV的輸電系統上面。相較於建置在輸電系統上數位保護電驛本身擁有的故障定位功能，到目前為止，本演算法展現出較數位電驛更精確故障定位成果與更強健的性能。

In this dissertation, an innovative fault location algorithm for two- and three-terminal multisection compound transmission lines using synchronized phasor measurements (synchrophasors) provided by Global Positioning System (GPS) based Phasor Measurement Units (PMUs) or digital relays with embedded PMUs or by pre-fault and fault-on relay data synchronization algorithms, is proposed. This dissertation addresses the fault location issues for non-homogeneous line models, which cannot be solved exactly by the existing fault location methods proposed in open literature yet. The proposed algorithm is extended from a two-terminal fault location method for homogeneous lines to the algorithms for two- and three-terminal multisection compound lines which combine overhead lines with underground power cables. Specifically, faulty branch selector, faulty section selector, and fault locator for two- and three-terminal multisection compound lines are proposed, which can not only distinguish an internal fault of a compounded line from an external fault but also have the ability to locate a fault on an overhead line or an underground cable as well. The proposed algorithm has a solid theoretical foundation and is direct and simple in terms of computational complexity since neither fault type selections nor iterative operations are required. Both extensive simulations and field evaluations have been presented to demonstrate the effectiveness of the proposed algorithm. The proposed algorithm has already been implemented in the Taiwan power system since the year 2008. So far the algorithm yields excellent performance and robustness compared to fault location methods of installed digital relays in Taiwan.