ZEMCH 2019 International Conference Proceedings April.2020 | Page 410
(a) (b)
Figure 2. Circuit diagram of accident experiment (a), Schematic diagram of accident scenario (b)
Figure 3. An equivalent circuit of a human body
Table 1. Model of human body
Case
(a)
(b)
(c)
Body State
Normal
Wet
Flooded
Body Resistance [Ω]
1780
825
82
4. Results
Figure 4‐(a) shows the magnitude of accident current over time after the ground accident. The
accident current analysis shows that AC accident current was present even though it was the ground
accident of DC side. Figure 4‐(b) shows a graph showing the magnitude of each harmonic with
frequency from the FFT(Fast Fourier Transformation) analysis of accident currents, which shows a
significant portion of the AC fundamental wave and the 2nd and 3rd harmonics components. This
enabled the inflow of AC accident currents, even though DC side ground accident in BIPV system with
non‐isolated inverter type applied.
In an accident current experiment with electrical continuity, we measured the human current and
voltage according to electrical continuity between (1) and (3) the two points, as shown in Figure 2‐(b),
when all of the system externalities came into contact with the human side of the BIPV frame due to
insulation accidents such as current conduct cables.
Under the same condition of irradiance, the electrical continuity values are varied from 0.5 Ω to 30
Ω, measuring the current and voltage flowing through the human body after the grounding accident,
and the results are shown in Table 2. Experiments have shown that in all cases where the electrical
continuity value is greater than 0.5 Ω, when a human body with Case 3,6,9 and 12 is considerably wet
(c), a current of more than 30 mA flows into the human body, which has a serious effect. If electrical
continuity is less than 0.2 Ω, it is believed that contact of the BIPV frame and all extraneous conductive
parts with both hands will not have a serious effect on the human body in a flooded environment, but
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ZEMCH 2019 International Conference l Seoul, Korea