| Title |
Coordination of Cascaded Metal Oxide Varistor-Based Surge Protective Devices |
| Authors |
Tae-Ki Kim ; Hee-Kyung Shin ; Bok-Hee Lee |
| DOI |
http://dx.doi.org/10.5207/JIEIE.2015.29.6.070 |
| Keywords |
Metal Oxide Varistor ; Surge Protective Device ; Energy Coordination ; Decoupler ; Voltage Protection Level ; Cascaded SPDs |
| Abstract |
This paper describes the experimental results obtained from various installation conditions of cascaded metal oxide varistor(MOV)-based SPDs with the objectives to analyze the coordination of the cascaded surge protective devices(SPDs) and to propose the proper selection and installation methods of the cascaded SPDs. The residual voltage, discharge current and energy sharing between the upstream and downstream SPDs in the 10/350μs direct lightning current wave were measured and discussed. The coordination of cascaded MOV-based SPDs is closely related to the varistor voltage and installation methods of SPDs. In cascaded SPDs without dedicated decoupling elements, the natural impedance of leads connecting two SPDs can act as a decoupler for the coordination of MOV-based SPDs. Even if the varistor voltage of the upstream SPD is higher than that of the downstream SPD at long distances between two SPDs, the energy coordination of cascaded SPDs could effectively be fulfilled in the conditions of large surge currents and the optimum voltage protection level can be achieved. Consequently, if the distance between voltage limiting type SPDs is long, the coordination of the cascaded SPDs should be determined by taking into account the decoupling effects due to the intrinsic inductance of leads connecting the upstream and downstream SPDs. |