- 學位論文
諧波對固態式測距電驛之影響模擬與探討
The Effects Study and Simulation Tests of Harmonics on Solid-State Distance Relays
摘要
本論文提出諧波對固態式(Solid-State)測距電驛之影響模擬與探討的研究，首先對測距電驛的特性作分類，並敘述各類測距電驛的動作方式與保護原理，接著再針對固態式測距電驛受到諧波及故障電阻的影響加以探討與說明，使模擬結果能與探討的情形作比較與驗證。 在模擬方面，本研究利用EMTP來建立輸電線模型，並模擬輸電線路發生接地故障，將模擬結果所獲得之故障電壓與電流值，經由建立資料庫的方式輸入由Matlab所建立之固態式測距電驛的模型，建立出一個完整的模擬系統，接著在模擬系統中加入各種不同含量之諧波電壓與電流，紀錄電驛受諧波影響後的動作時間，並探討其結果，以達成本研究的主要目的；利用這種模擬方式，不僅可以對電驛作詳細的模擬與研究，更可以減少錯誤與模擬的時間。 最後，針對模擬與探討的結果提出固態式測距電驛在設定上的考量與建議，首先可以考慮由模擬結果的影響情形，更改電驛的保護區阻抗設定值，以降低電驛誤動作的發生，另外亦可考慮於電驛內部加裝低通濾波器的裝置，以濾除諧波成份。 本研究的探討與模擬結果期能提供研究與使用測距電驛方面的相關人員作為應用與參考。
並列摘要
This study presents the effects study and simulation tests of harmonics on solid-state distance relays. There are different types of solid-state distance relays at present day, but based on tripping designs ,they can be separated into two types：rectifier type and phase-comparator type. These two types are taken into simulation. The effects study of harmonics and fault resistance to the solid-state distance relay is done first. Then the results are compared with the simulation results. A new method for the simulation of distance relays is presented. EMTP is used to build the transmission line model and to simulate the grounding fault situations. Then the output voltage and current values of EMTP are saved in Microsoft Excel data type. The advantage of this method is the unnecessary data can be deleted before simulation for saving simulation time and reducing errors. Different kinds of harmonics combinations are used as inputs of the simulation system to study the effects on solid-state distance relays built from MATLAB. From the simulation results, we learn that the solid-state distance relay did not perform well at harmonic environments. The tripping time of the relay is delayed for both types of distance relays. This means the protection zone of the distance relay will change and misoperations may happen. Extensively study is the suggestions of the function of distance relay in an environment with harmonics. This paper proposes two methods to reduce the misopearations of the relay at such environment. First method is how to adjust the settings of protection resistance of the distance relay at specific conditions to ensure that the relay trip properly at fault situations. The second method is to equip low pass filter to the relay. The results of this research can provide valuable references and assistance in applying and designing of distance relays’ protective schemes.