Power system interconnection is a well established practice for a variety of technical and economical reasons. Several interconnected networks exist worldwide for a number of factors. Some of these networks cross international boundaries. This Study discusses the future developments of the electrical interconnection between the Maghreb countries” Algeria, Tunisia, Morocco” and Europe via the line “Morocco-Spain”. And that any deficiency in power of the Algerian network will be compensated directly from the European network passing through the Moroccan network and this is the main purpose of the construction of the 400 kV network for widen the electrical interconnection between the Mediterranean countries.