A new 3-D TLM-TW (Transmission Line Matrix - Twin Wire) numerical scheme is proposed for modeling thin wires buried in a general inhomogeneous, dispersive, conductive medium. To solve the time convolution product introduced by the dispersive medium, a recursive algorithm obtained by bilinear Z-transform approach is used. This technique is developed for electrically dispersive media (i.e. magnetically non dispersive) and its generality allows the use of any kind of Debye and Lorentz models or media represented by a ratio of polynomials with full power of (jw). The TLM-TW numerical scheme is first validated through the simulation of a canonical thin lead cable surrounded by homogeneous Lorentz dispersive medium. Then, the numerical study of an umbrella antenna, radiating structure typically used in VLF transmission, is investigated.