Grid interconnection delays are the most common and most avoidable cause of commissioning overruns in C&I solar projects. A multi-MW open access or captive plant can be fully installed and ready to generate — and sit idle for months waiting for DISCOM approvals that were not properly planned from the outset.
Here is a structured guide to what most facility owners get wrong, and how to avoid each mistake.
- Treating grid interconnection as someone else's scope Many EPC contracts for C&I solar define the scope as "up to the HT metering panel" — effectively excluding protection coordination, relay settings, and DISCOM approval management from the contractor's responsibility. The facility owner then coordinates separately with consultants and the DISCOM, creating a gap between parties with no shared incentive to resolve interface conflicts quickly. The correct approach is to ensure grid interconnection is within the EPC contractor's scope (with clear accountability) or contracted separately with an explicit interface agreement defining the handover point, testing protocol, and commissioning sequence.
- Starting the interconnection approval process too late DISCOM interconnection approvals in India involve a sequential process: load flow study submission, protection coordination review, relay setting approval, and finally a synchronisation test witnessed by the DISCOM engineer. In states like Rajasthan, Karnataka, and Tamil Nadu, this process routinely takes four to eight months from first submission to final approval. The submission process should begin early in the project timeline — ideally at engineering stage, not after modules are installed. Any facility that waits until installation is complete to start the interconnection application will face months of delay before the plant can export power.
- Under-specifying the protection system The protection and control system for a C&I solar interconnection must be designed in coordination with the DISCOM's grid protection scheme. This requires a detailed protection coordination study — not generic relay settings reused from a previous project in a different state. Common consequences include nuisance tripping during grid disturbances, failure to ride through low-voltage events as required by grid code, and rejection of the synchronisation test by the DISCOM engineer.
- Underestimating HT infrastructure requirements Large C&I open access projects may require dedicated HT infrastructure — transformers, switchgear, and cabling sized for the facility's export profile. Specifying equipment purely on lowest capital cost — without considering efficiency, thermal cycling from solar generation profiles, and lifecycle warranty — leads to failures within the first five to seven years of operation.
- Not planning for capacity expansion Many facilities plan interconnection for current project capacity — then face costly upgrades when they add a second phase or expand open access allocation. A forward-looking design accommodates future capacity in civil and structural works, even if additional electrical equipment is not installed at commissioning.