A Study on Active Islanding Detection Technologies in Solar Photovoltaic System

• Main Authors: Tung-Yu Tsai, 蔡東育
• Other Authors: Hong-Tzer Yang
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/77813710000139374937

碩士 === 中原大學 === 電機工程研究所 === 95 === In a grid-connected solar photovoltaic (PV) system, as grid is disconnected from the solar PV system, if the disconnection is not detected and the PV system operated independently, it is called “islanding operation”. The detection methods can be categorized into passive and active approaches. The passive detection approaches suffer from the existence of un-detection zone (UDZ). Also, exist the issues of active approaches with high cost, power losses, and un-detection zone in the detection process. Therefore, to improve the UDZ drawbacks of the existing active Slip-Mode Frequency Shift (SMS) method, a nonlinear jumping SMS scheme is proposed in the thesis. In the proposed scheme, more perturbation is introduced to the shifting angel, as the stable operating point is approached in the existing SMS method. The time needed by the SMS method around the stable operating point can also be reduced via the proposed scheme. To verify feasibility of the proposed islanding detection scheme, the islanding operating models are established to investigate the detection performance of the proposed scheme and existing SMS method around the stable operating point via the simulations in Matlab. In the simulation tests, the environment with various power quality events is included for verification of the proposed islanding detection scheme. In practical experiments, employed is a current-control voltage source inverter with the core of a digital signal processor (DSP) where the islanding detection capabilities are built. The experimental results the detection performance and UDZ of the traditional SMS method are improved by the proposed scheme. It is proved that the proposed detection scheme can still detect the islanding operation around the stable operating point.