500台規模太陽光発電システム集中連系時の単独運転検出機能のY法解析手法

摘要

多数のPVシステムが集中連系された配電系統の安全性解析に役立てるため，新たにY法による単独運転特性の多数台・高速解析手法を開発した。新手法の妥当性を検証するため，従来のEMTPによる単機解析結果との比較解析，およびPCSの単機性能試験結果との比較評価を行ない，妥当性を確認した。また，これをPVシステム500台まで拡張するとともに，実証試験地区城西の杜を想定した解析モデルを作成し，総数344台（平成17年度実績）のPVシステムを含む配電系統の単独運転特性解析を行なった。得られた成果は，今後の太陽光発電の大量導入時における安全性評価に際し，大いに役立つものと考える。%Since the FY2003, the demonstration site Josai-no-mori including over 500 residences with PV system has been under construction at the Ota City, Gunma prefecture in Japan. It is important to clear the safety of islanding protection. However, it is very difficult to verify the islanding phenomena including many PV systems on the actual utility grid, where the people are leading life actually. Therefore, it becomes important to develop a technique employing simulation analysis for the safety evaluation. Purpose of our study is to clear the details of dangerous islanding phenomena and the effects of various protection methods under clustered installation of over 500 PV systems within a partial area of utility grid. To solve these problems, a new analysis method has been developed, that is based on the CRIEPI's Power system Analysis Tools (CPAT) technology implemented by CRIEPI, so called "Y-method". As a noteworthy result, it has been confirmed that the new simulation method has a capability to expand to the large-scale clustered installation model including 500 PV systems on utility grid. The validity of simulation analysis has been verified by comparing with preliminary indoor tests. In addition, it has been clarified that the combination of passive and active protection methods is very effective to avoid the islanding phenomena.