基于广义S变换能量值信息熵加权的DG电网故障判断研究

Research on Fault Phase Selection of DG System Based on S-transform Energy

为解决分布式电源(Distributed Generation,DG)并网影响暂态故障特征,造成故障误判断,本文提出通过比较信息熵加权的广义S变换能量值的方法来进行故障判断,不仅能利用故障后极短时间内对数据进行故障判别,而且不受故障角与过渡电阻的影响,大大提升了判断的可靠性。本文通过对获取故障分量电流进行广义S变换,对变换后的各频段能量值进行信息熵的加权处理,处理后的结果作为选相参数来实现故障类型判断和选相,最后通过PSCAD建立DG并网模型仿真验证了该方法的可行性。

In order to solve the transient malfunction characteristics which are influenced by the interconnection of distributed generation leading to the wrong judgement of malfunction. In this paper,we propose a method to determine the transformation energy value of the generalized and information entropy weight-S,which can not only distinguish the faults of the data in the short time after the fault,but also can not be affected by the fault angle and the transition resistance,so it greatly improves the reliability of the judgment. In addition to that,the generalized S-transform is obtained by obtaining the fault component current; after that,the energy values of each frequency band after the transformation could be weighted processing of information entropy. And the result of processing is used as the phase parameter to realize fault type judgment and selection. Finally,the feasibility of this method is verified by using PSCAD to establish DG grid-connected model.