With the great available technological advances, MVNs are still difficult to control, because of their dense meshing and their automation is very cost-intensive. There are generally no communication cables in the MVNs' equipment such as the MV transformer and distribution stations. One of the costless technologies used to communicate between the MVNs' equipment and the control center of a SCADA system is the DLC communication technology, where, data transfer occurs directly on the medium voltage cables, i.e. on the conductors of the underground and/or the overhead cables or on the shields of the underground cables. However, the DLC system suffers from many problems concerned in MVNs. In addition, the design of the DLC system itself has some defects, which affect its performance and stability. Here, we explain with simulation the exits instability margins of the operation of the DLC system to help us how we can improve the stability margins of the system to achieve a good performance