太陽電池モジュール / ストリングと大地の間の等価回路の提案（3）

- 一年間の屋外測定を経た本研究の総括，そして感電リスク予防のためのアレイ設計法の一試案の提示 -

抄録

To promote practical discussion on electrical risk of photovoltaic power generation plants such as fire and electrical shock caused by decrease in insulation resistance between photovoltaic module/string and the ground, author has proposed a new theory for the equivalent circuit of the photovoltaic module/string against the ground based on one-year outdoor measurement with three kinds of photovoltaic modules. This equivalent circuit consists of seven RC-components, each of which has different attenuation frequencies ranging from 10⁵Hz to 10^-3Hz. The RC-component with 10⁵Hz-frequency has extremely low resistance. On the other hand, the RC-component with 10^-3Hz-frequency has high resistance.

By applying both this equivalent circuit theory of PV module/string against the ground and the upper limit of human body charge, author has also suggested a PV array design theory to prevent unexpected electrical shock assuming wet condition. Maximum permissible number of strings in parallel is strongly restricted by square of number of modules in series, in other words, system voltage. Therefore, high system voltage should not be recommended from a viewpoint of electrical safety even though the high voltage has economical advantage for the photovoltaic power generation plant.