Development of the miswiring detection circuit and software algorithm for safe installation of SPDs for low-voltage distribution system

초록

- In this paper, we propose a detection circuit and a software algorithm to prevent wrong wiring connection of CT2 SPD. Most of domestic low-voltage consumers are supplied from the KEPCO with TN-C grounding system, but the load facilities are mainly based on TT grounding system. Therefore, in order to prevent damage caused by lightning, most SPDs use a CT2 type SPD that can be suitable for both TN-C and TT grounding. There is no separate bus-bar for the outdoor electric enclosures such as CCTV, so it is difficult to distinguish between the phase and neutral cable. In this environment, the phase and the neutral cable may be connected in reverse by mistake of the installer. However the status indicator of SPD is displayed as normal even under the inverse wiring condition. If a surge enters in this condition, the SPD will be damaged and the electricity supply may be disrupted. The proposed detection circuit and software algorithm are expected to be useful for preventing miswiring of SPD. Copyright © The Korean Institute of Electrical Engineers

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