Following are the Limitations of EHVAC Transmission:
1. Insulation cost increases as voltage increases
2. Skin effect is more
3. Proximity effect is more.
4. Corona loss increases.
5. Radio interference increases
6. String efficiency is less than100%
7. Ground return not possible.
8. Voltage control is not easily possible.
9. Power flow cannot be easily controlled.
10. Short circuit current level is more
11. In case of EHVAC, Intermediate substation is required at every 250 km to improve the performance of transmission line
12. If power is to be transmitted of EHVAC through underground cable then there is limitation on the length of cable due to charging current. e.g. for 400 KV line limitation on length of cable is 25 Km
13. Asynchronous tie not possible.
14. Stability of EHVAC is very low because of presence of inductance.
15. Transient performance is poor.
16. There is limitation on power transfer due to presence of inductance of transmission line & power angle.
17. To improve the performance of transmission line additional equipments such as series & shunt reactor & capacitor are required which increases cost of substation.
18. EHVAC is economical only for bulk amount of power is to be transmitted over long distance.