Japan's sub-transmission network system (77 and 66 kV) has been modeled. These three main types of models are described as bellows;
Fig. 2.1 (PDF File)
System I : 77 kV Overhead transmission systems (overhead line systems)
System II : 77 kV Cable transmission systems (cable systems)
System III : 66 kV Mixed overhead line and cable systems (mixed overhead-cable systems)