Fault Transient Signal Wavelet Analysis Based Power System Protection Technique for Distributed Generation Systems

The distributed sources such as wind turbines, solar, micro-hydro-turbines, etc. are more and more used as an alternative to the traditional resources. The distributed generations are more popular in the power system. As the penetration of distributed generations is increasing, the effects of distributed generation on the traditional power system should be investigated.

Owing to the penetration of the distributed generations, some basic preconditions of the traditional distribution power system will be changed, such as the topology of distribution power grid which will be shifted from the uni-source radial network to the multi-source topology; the power flow which could be changed to bi-directional load flow instead of traditional uni-direction load flow; the fault level which will be mainly affected by the type and capacity of DGs and the connection technologies of DGs; and the characteristics of the faults and the fault current distribution could be affected, so as to impact the protection arrangement, for instance the coordination, selectivity, sensitivity of protection scheme.

The focus of this project is set on the investigation and analysis of techniques for power system protection when the distributed generations are connected to the distribution power system.

When the distributed generations are connected to the power gird, the protection coordination should be studied again. In this situation, the protection coordination can be classified into 2 aspects: 1) The selectivity of the protection; 2) The coordination of power quality and protection.

The distributed generations will change the distribution of the fault current, so the coordination between fuse and recloser should be studied to satisfy the selectivity of the protection. And the power system could be disturbed by the faults, so the power quality could be impacted. Both the DGs control strategies and the protection arrangement will affect the power quality. The influence of protection on power quality should be investigated.

Additionally, the micro-grid could be appearing. In this situation, the parameters of the system would be drastically changed, so the protection arrangement should be investigated again to satisfy the selectivity, sensitivity, and reliability of the protection.

The goal of the project is to investigate the effects of distributed generations on the power system protection, and to study the methodology in the protection arrangement and coordination.