No permits would be needed, if you are going to install off grid Solar PV system or grid connected system for captive (self) consumption. For net metering and gross metering system, certain permits and approvals are required.
For Net & Gross Metering:
1. Approval from DISCOM for grid connectivity.
2. CEIG(Chief electrical inspector to the government of state) approval for the capacity more than 10 KW(This capacity may vary from state to state).
For detailed process click here