臺灣博碩士論文加值系統

輸電線在電力系統中扮演重要的角色，故當輸電線發生故障時，儘速找出故障位置以修復故障便為當務之急。非同步量測是阻抗型（Impedance-based）故障定位方法不準確的一個問題，以往需以相量量測單元（Phasor Measurement Units, PMUs）及智慧型電子裝置（Intelligent Electronic Devices, IEDs）結合全球定位系統（Global Positioning System, GPS），從匯流排上同步取樣訊號，但前述設備的建置成本高昂且傳輸訊號如因故中斷將造成該故障定位方法無用武之地。此外，雖已有利用疊代方法解決非同步取樣造成的故障定位問題，但疊代法僅能得到近似結果。奠基於以非同步量測訊號準確的定位故障及避免使用昂貴的基礎設施，本文提出了一種新型故障定位演算法以解決前述非同步量測的故障定位問題。本方法藉由正序相量信號疊加技術，經過數學的推導分析得到故障定位指標，利用該指標得以準確的以非同步量測資料進行故障定位，且不需要疊代、選擇故障類型、假設故障電阻等。本方法以MATLAB / SIMULINK模擬，針對各種非同步測量案例進行故障定位指標有效性的驗證，結果顯示此演算法具有很高的準確性。再針對故障定位指標進行比流器飽和（CT saturation）、比壓器暫態（CVT transient）、故障起始角度（fault inception angles）、頻率變動（frequency deviation）、輸電線參數誤差（transmission line parameters errors）、無換位輸電線路（untransposed transmission line）等可能造成故障定位指標準確度變化之原因進行敏感度測試。除了模擬測試，本故障定位指標亦分析台灣電力公司的2個實際事故案例，並將本指標與測距電驛的結果進行比較，驗證本方法具有解決實際非同步量測的故障定位問題。

Transmission lines (TLs) play a key role of the infrastructure to supply electricity. It is important to find the fault positions quickly and accurately when a fault is on TLs. One of the biggest problems of the two-end impedance-based method is unsynchronized measurements. To solve this problem, Phasor Measurement Units (PMUs) and Intelligent Electronic Devices (IEDs) are combined with Global Positioning System (GPS) for the purpose of synchronizing the measurement information between buses. However, since it is too expensive to deploy GPS-based PMUs and IEDs throughout the whole power systems, the unsynchronized conditions (UC) is still encountered today. Besides the reason of cost, the measurement information between buses could also be out of synchronization due to GPS Signal Loss (GSL). As a result, to solve the UC problem, numerical iterative methods were applied to correct the unsynchronized angle and then to identify a fault position. Yet, using iterative methods can only derive an approximate fault position. With a view to finding the accurate solution to a fault point without costly expenditure on infrastructure, the current study proposes an innovative fault location technique to solve this problem. By using the proposed superimposed plus positive-sequence phasor method with its exclusively mathematical logic, one can calculate a　fault location index and find an exact distance to fault using unsynchronized measurements without iterative operation, multiple steps, fault-type selection, and fault-path resistance assumption. The proposed fault location method has been verified by using the MATLAB/SIMULINK® simulator with the distributed parameter model for the two-end transmission line, which shows highly accuracy on pinpointing a fault based on unsynchronized measurement information. Sensitivity analyses (i.e. CT saturation, CVT transient, fault inception angles, frequency deviation, transmission line parameters errors, and untransposed transmission line) have been conducted to demonstrate that the developed algorithm gives accurate responses and the errors are at the level achieved under various system and fault conditions. In addition to model tests, the performance of the proposed method is also evaluated by using 2 field cases obtained from the Taiwan Power Company (Taipower). Compared to the errors of IED, the proposed idea provides more accurate results, which also verified the ability of the proposed method on solving actual fault location problem.

摘 要 i
Abstract iii
Contents v
List of Tables vii
List of Figures viii
Chapter 1. Introduction 1
1.1 Motivation and Literature Review 1
1.2 Contribution and Aim 3
1.3 Structure of this thesis 4
Chapter 2. Methodology 5
2.1 Long Transmission Line Model 5
2.2 Review of the Synchronized Fault Location Technique 8
2.3 The Proposed Fault Location Algorithm 10
2.4 Verification of the New Algorithm under the Situation of Unsynchronized Sampling Information from IEDs 15
Chapter 3. Performance Evaluation 18
3.1 A Brief Comparison of the Proposed Method Using Synchronized and Unsynchronized Sampling Information 18
3.2 Statistical Analysis 20
3.3 Sensitivity Analysis 27
3.3.1 CT saturation test 27
3.3.2 CVT transient test 28
3.3.3 Different fault inception angles 29
3.3.4 Frequency deviation test 29
3.3.5 Transmission line parameters test 30
3.3.6 Effect of Untransposed Transmission Line 31
3.3.7 Errors in the IEDs Sampling Rate 31
3.3.8 Field Test Performance 36
Chapter 4. Discussion, Conclusion, and Future work 37
4.1 Discussion 37
4.2 Conclusion 40
4.3 Future Work 41
Reference 42
Appendix A 46
Appendix B 47

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