A device for replacing a linear active DC electric circuit with respect to two poles comprises an ideal EMF source connected to the two said poles through a series-connected resistor and shunted by a parallel-connected resistor, wherein the EMF value is equal to the DC electric circuit voltage between the two poles in the open circuit mode, the resistance value of the series-connected resistor is equal to the ratio of the specified breakdown voltage to the current of the DC electric circuit between the two poles in the mode of their closure, and the resistance value of the parallel-connected resistor is equal to the ratio of the square of the breakdown voltage to the total power of the consumers of the DC electric circuit in the mode of pole breakdown. Additionally, a dependent current source is introduced, controlled by the current of the said series-connected resistor, the output terminals of which are connected to an ideal EMF source, and the transmission coefficient is equal to a reduced fraction, the numerator of which is the difference in power of all consumers of the DC electrical circuit in the modes of closing and breaking the poles, and the denominator is the product of the fault voltage by the specified fault current.