In low-voltage distribution networks there exist commonly issues, such as large gaps between peak and valley loads, three-phase unbalance, voltage dips, etc. Therefore, as a measure for strong power grid construction, it is of significance to update and reconstruct the existing distribution systems and overcome their weaknesses. As an emerging technical solution, energy storage is capable of delaying or reducing the capacity expansion and construction of equipment in distribution systems, providing active and reactive power supports, improving power supply reliability and power quality, achieving peak shaving and valley filling of loads, etc. In low-voltage distribution networks, energy storage units are of modularization and miniaturized scale, and installed in distributed manner. As physical space for equipment is strictly limited in power conversion systems, it is not suitable to use the bulky air-core inductors although with desired inductance linearity, thus iron-core inductors in relatively smaller size are generally adopted as the filtering inductor at the output. However, the iron-core inductors have shortcomings such as magnetic saturation in their iron cores, inductance nonlinearity, as well as excessive noise and large power losses in operation. As a solution to the above-mentioned situation, a scheme of linear filtering inductor integrated in isolation transformer in energy storage power conversion system is proposed. By means of theoretical analysis with electromagnetic field theory, finite element simulation, and prototype experiment, the characteristics of electromagnetic decoupling and inductance linearity of the proposes transformer integrated filtering inductor are investigated. It is validated that the proposed scheme is feasible.