摘要
研究一种新的分布式发电系统被动式孤岛检测方法,其主要用于检测功率平衡状态下发生的孤岛,并由此提出虚实阻抗概念,在非孤岛并网运行条件下,因电网电压的存在,基于并网电流和电压值获得的阻抗数值实际是一种虚阻抗;孤岛发生时,获得的阻抗数值才是实际阻抗值。利用孤岛发生时虚实阻抗的变化和电网系统的谐波失真,构建一种谐波阻抗特征函数用于特征量提取,并借助BP神经网络进行孤岛检测。理论与实验表明,根据特征函数选取的特征量孤岛前后区别明显,有助于孤岛检测,证明了该孤岛检测方法具有可行性和有效性。
A new passive islanding detection method for distributed generation（ DG） is studied which is mainly used for detecting the islanding in power balance,and therefore the concept of virtual and real impedance is proposed. In non-islanding grid-connected operation conditions,due to the presence of grid voltage,the impedance value obtained by grid-connected current and voltage is actually virtual impedance; when islanding occurs,impedance values obtained is the actual impedance. The new method exploits difference between virtual and real impedance and harmonic distortion of grid system to construct harmonic impedance characteristic function which is used for extracting features and then to detect islanding operations by BP neural network. Theory and experiments show that,the features extracted from characteristic function obviously different before and after islanding are helpful for islanding detection; and the islanding detection method is feasible and effective.
出处
《电工电能新技术》
CSCD
北大核心
2015年第12期37-42,64,共7页
Advanced Technology of Electrical Engineering and Energy
基金
国家电网公司科技项目(NY71-13-036)
