In this paper， we propose a method to accurately detect a current deriving from equivalent ground –isolation resistance value. This method is capable to calculate 0-cross point to I₀ and phase angle, taking voltage V(T→R) as a basis，without applying current of different frequency. Capacitance value，which is a fluctuating factor，is not adopted in the calculation so that the method is kept simple and stable. As well，this method has an advantage over others in terms of the speed of fixing the results and is stable.

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The installation of various distributed power supplies promoted in recent years，and it is expected to be going to highly increase in the future. From the viewpoint of electric power utilities，the connection of a lot of different types of small capacity power supplies will present problems with the electric power qualities such as the increase of short-circuit capacity，the voltage and the frequency fluctuations. The introduction of a fault current limiter (FCL) is expected to be promising method for solving these problems. In this paper，the suitable installation of the FCL into the wind park consisting of ten wind generators is investigated. The fault currents from ten wind generators were calculated under the short-circuit fault condition at the connecting point between power utility system and wind park one. The simulations were carried out for two cases，one is the case that the FCL was applied only at the connecting point，another is that ten FCLs were installed at the feeders of every wind generators. The each fault current from ten wind generators can be most effectively reduced by the R-type FCL applied at the connecting point. In the real equipments，however，the type of FCL should be selected from the view point of not only current limiting effect but also the size and cost of FCL.

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