Experimental investigation of the coordination between SPDs and between SPD and the protected equipment

Abstract Surge Protective Devices (SPDs) are widely applied to protect the low-voltage equipment against the surges from direct lightning strikes or the lightning-induced effect. To ensure the protection effect, the users should not only consider the performance and quality of the SPDs themselves, but also the coordination between SPDs and between SPD and the protected equipment. In practice, there may be SPDs with different characteristics from many manufacturers on the same line. One SPD is installed by the contractor in charge of electrical installation and then various panel boards are used in the installation made by various panel builders. All of them may use different brands of SPDs. So it is difficult to evaluate the coordination effect between those SPDs and between SPD and the protected equipment by theoretical analysis. A solution would be to perform the coordination test. This paper provided an investigation on the proposed coordination test method for different configurations with various loads, various cable lengths, various cable enclosures and various surge waveforms through experiments in the laboratory. The sharing current and residual voltage of two cascaded SPDs were measured and discussed. The proposed coordination test method was verified to be informative for achieving successful coordination between SPDs and between SPD and the protected equipment.