400 கி.வோ துணை மின்நிலையங்கள்
| S.NO | NAME OF THE SUB-STATION | VOLTAGE RATIO IN KV | COMMISSIONING DATE |
| 1 | SRIPERUMBUDUR | 400/230-110 | 13-03-1987 |
| 2 | K.R.THOPPUR | 400/230-110 | 20-03-1988 |
| 3 | ALAMATHY | 400/230-110 | 25-05-2006 |
| 4 | SUNGUVARCHATRAM | 400/230-110 | 16-08-2011 |
| 5 | KAYATHAR | 400/230-110 | 04-07-2014 |
| 6 | THIRUVALAM | 400/230 | 27-07-2014 |
| 7 | KARAMADAI | 400/230-110 | 24-08-2016 |
| 8 | KAMUDHI | 400/230-110 | 08-09-2016 |
| 9 | KANARPATTY | 400/230-110 | 09-01-2017 |
| 10 | DHARMAPURI (PAALAVADY) | 400/230-110 | 15-03-2017 |
| 11 | MANALI | 400/230-110/33/11 | 25-07-2017 |
| 12 | RASIPALAYAM | 400/230-110 | 31-08-2017 |
| 13 | ANAIKADAVU | 400/230-110 | 06-11-2017 |
| 14 | SHOLINGANALLUR | 400/230-110 | 27-12-2017 |
| 15 | THAPPAKUNDU | 400/230 | 23-10-2018 |
| 16 | THENNAMPATTY (PAVOORCHATRAM) | 400/230-110 | 05-11-2019 |
| 17 | OTTAPIDARAM | 400/230-110 | 22-03-2023 |
| 18 | PULIANTHOPE (GIS) | 400/230 | 24-03-2023 |
| 19 | VELLALAVIDUTHI | 400/230 | 04-10-2023 |