| Topology | No. of medium Voltage with 2 rings | No. of medium Voltage with 3 rings | No. of medium Voltage with 4 rings | No. of medium Voltage with 5 rings | No. of medium Voltage with 6 rings | Total no. of substations |
| A | 3 | 5 | 18 | 12 | 8 | 1051 |
| B | 12 | 17 | 8 | 10 | 7 | 1049 |
| C/D/E (connected differently) | 2 | 8 | 13 | 11 | 11 | 1050 |