Fault Line Detection Based on Rough Set Theory in Indirectly Grounding Power System
Fugang Yang · Proceedings of the CSEE · 2007
The principle of the fault line detection method based on wavelet packet transform is analyzed. It is showed that the method is invalid when the energy-loss of the sampled transient zero sequence current signal of fault line is large. In order to overcome the limitation of the method, an improved fault line detection method based on rough set theory is presented. The extracted fault characteristics of transient zero sequence current is looked as condition attributes and the multiple of signal enhancement is looked as decision attribute. So the decision system of fault line detection is constructed. After decision table reduction, the minimal decision rules can be obtained and the rules will be used to perform signal enhancement. The enhanced signal can be decomposed by wavelet packet transform to realize fault line detection. The ATP-EMTP simulations indicate that this method has effectively raised the accuracy of the fault line detection in indirectly grounding power system.