- 學位論文
併接離岸風場之長程輸電系統測距保護電驛適應設定與模擬研究
Research on Adaptive Setting and Simulation of Distance Protection Relay in a Long Transmission System Connected to an Offshore Wind Farm
摘要
離岸風力已經逐漸成為全球再生能源發展的主軸之一。在台灣，幾部示範型離岸風機將規劃在2015年建置完成；而在2020年前，至少建置超過300MW的離岸風場。當離岸風力的裝置容量增加後，更可靠的風場保護系統將急迫需要。離岸風場保護系統一般區分為不同的保護區間，包含風機本身、風場內部接線系統、風場與外部電網的連接系統、以及併接電網周遭系統等。不同的保護範圍以及系統元件需要規劃不同的保護機制以及電驛設定。本案例針對風場至陸岸併接點之間的傳輸線路保護進行探討，並提出測距電驛之適應設定方式以及保護機制、採用連接台灣本島系統與澎湖離岸風場的傳輸線路作為實際的模擬分析。首先將實際的系統以一等效電路模型表示，並推導測距電驛之視在阻抗數學公式，進而獲得在各種情境條件下之電驛特性跳脫邊界，這些非線性之跳脫邊界應用於一典型有四個跳脫區間之電驛模型。此外，風場中一些不可控制的因素對於跳脫邊界之影響已考慮在本計畫的模擬工作中；這些系統不可預期的干擾包括風速變動、系統短路故障、系統元件故障所造成之電壓變動、以及電網端的負載變動等。本文已利用電力專業分析軟體進行這些案例分析，並評估本文模擬設定的適應性測距電驛之可行性。
並列摘要
Offshore wind power has become the focus of the world’s renewable energy development. In Taiwan, several demonstration offshore wind turbines will be scheduled to be established by 2015, and more than 300MW capacity of offshore wind farm to be installed by 2020. As the penetration level of wind energy increases, more reliable protection systems for offshore wind farms are required. The wind farm protection system is usually divided into different protection zones including the wind farm area, wind farm collection system, wind farm interconnection system and the utility area. Different protective zones have different protection schemes and relay settings. This project has proposed an adaptive distance relay that protects submarine cables between an offshore wind farm and an AC grid. The double-circuit submarine cables that connect offshore wind farm in Penghu and Taiwan grid will be utilized as an example. First, the apparent impedance of the relay is mathematically derived using a detailed equivalent circuit model, and the characteristic trip boundaries of the relay in various scenarios are obtained. The nonlinear characteristics of the trip boundaries that are used in a typical distance relay with four protection zones will be discussed. Furthermore, the effects of the uncontrollable factors on the performance of a distance relay have been considered into the simulations. These system disturbances include wind speed variation, system short circuit faults, or system component failures. These case studies have been presented using the simulation package to evaluate the feasibility of the distance relay setting that is developed in this project.