Multi-winding transformers as main part of multiport phase shift converters play an important role in integration of renewable energy sources, storage device and loads. The range of power transfer in multi-port phase shift converters particularly depends on the leakage inductance of multi-winding transformer. Numerical analysis such as 2D and 3D finite element methods have been widely used in analysis of magnetic structures and estimation of leakage inductance although their computation time is the main issue especially in online and iterative design processes. In this paper, a 3D reluctance network is introduced for modelling of magnetic flux distribution and estimation of self and leakage inductances of multi-winding toroidal core high frequency transformer. The proposed network is formed in cylindrical coordination, according to the geometrical shape of toroidal core. The effective factors on accuracy of model and computation time are studied and the results are compared with experimentally measured parameters to verify the accuracy of model.