Optimization Algorithms For Fault Location Based On Travelling Waves

Fault location with high availability and reliability is the guarantee of safely operation for power system. The present fault location methods have their drawbacks separately, correspondingly traditional fault location methods are not perfect yet. An in-depth research on fault location system is still of great significance.According to travelling wave theory and fault information system, optimization algorithms for travelling wave based fault location are proposed in this thesis. Major points of this thesis are listed as follows:(1) Based on singularity value decomposition and wavelet transform, a singularity point detection method for travelling wave with strong superimposed noise is proposed. Simulation results show noise can be eliminated effectively by singularity value decomposition, and travelling wave signal singularity can also be maintained. Combined with traditional wavelet transform, singularity point for travelling wave under strong noise background can be detected accurately.(2) A novel singularity point detection method for weak travelling wave is proposed. The singularity point of weak travelling wave which generally is difficult to be detected correctly, is determined by fitting curve based on least square algorithm in this new method. After expression equations for weak travelling wave front are gained, singularity point can be determined by curve fitting. This method can effectively improve the accuracy and reliability of singularity point detection for weak travelling waves.(3) Based on the travelling wave theory, a new algorithm taking advantage of treble terminal travelling wave data is presented. By measuring the different times when initial travelling wave surge arrives at the reference bus, the opposite bus of the fault line and the opposite bus of the vicinal sound line, the influence of wave velocity and transmission line radian is eliminated to a certain extent.(4)The characteristic of reflection and refraction in teed circuit are analyzed detailed, and a novel algorithm for distinguishing fault branch and locating fault point is put forward. It utilizes the travelling wave data of all teed circuit terminals, and can improve the reliability of fault branch distinguishing and accuracy of fault location effectively. Besides, A novel single ended travelling wave fault location algorithm for teed circut,which combines traditional impudence method result in master station of fault information system, is proposed. Travelling wave based method will work in this algorithm for the case that only one terminal travelling data can be uploaded to the master station. This method expands the scope of travelling wave method application obviously.(5) Travelling wave signal generator is necessary for development and test of new travelling wave based fault location devices. High speed operational amplifier,synchronous analogue output board and a PC are used for assembling travelling wave signal generator in this thesis. It can produce travelling wave signal in all kinds of fault conditions, and provide premise for development and test of new devices.(6) According to research in this thesis, a new generation of fault traveling wave based fault location device is developed. The fault data are processed according to the proposed algorithms in this device. Now this kind of device is test running in good condition in the real field.