Research On SPD Allocation Optimization And Coordination With RCD In Buildings

Surge Protection Device (SPD) is an appliance designed toprotect electrical devices from voltage spikes, SPD attempts to limitthe voltage supplied to an electric device by either blocking or byshorting to ground any unwanted voltages above a safe threshold.In this thesis, the purpose is to research on optimize allocation ofSPD in buildings and SPD coordination with other surge protectors.Surge response of transmission line in buildings, loads impact by surgeand SPD coordination with other protectors are researched.Transmission line theory is discussed in the thesis. Partial ElementEquivalent Circuit (PEEC) method is used in the discussion for modelingthe electromagnetic behavior of arbitrary three-dimensional electricalinterconnection structures. Numerical calculation of the PEEC is derivedin the thesis and vilified by comparing calculation result with theATP/EMTP software.Ground effect is considered in the PEEC model. Measurement of thesoil parameters is discussed and measurement results are used in thePEEC model. PEEC transmission line theory based on Dyadic Green Function (DGF) over real ground is derived. Importance of ground effectis proved due to calculation result comparison between perfect groundsituation and real ground situation. Vertical line and horizontal line modelare derived by the author and SPD installation is discussed in each model.Load is another important factor which may have great effect in thesurge transmission. Electric loads are now widely used in buildings,which cannot model with linear elements. Two typical electric loads(ballast and SMPS) are discussed in surge situation. Surge models of thetwo loads are given in the thesis and verified by comparing with testresult of the laboratory experiments.Residual Current Device (RCD) is widely used in buildings toprevent accidental electrocution. Besides it can trip when fault situationdetected. Noise tripping of RCD also may happened when surge passthrough. Experimental investigations into operating characteristics ofRCD are done under unbalanced current. The unbalanced current includethee harmonic current, ground fault current, and surge current. A testingsystem is set up in the laboratory, and the minimum values of the currentcausing RCD samples to trip are recorded. The research can help with thecoordination of SPD and RCD.Whole surge model of the building is derived and verified bycomparing with the experiment result, which can help with the SPD allocation optimization. Coordination with RCD should also beconsidered when considering the SPD allocation optimization.