Telangana Grid Interconnection
TGNPDCL Net-Metering & Solar Interconnection Guide
Technical feasibility norms, voltage thresholds, bi-directional metering specifications, and utility liaison for rooftop solar under Northern Power Distribution Company of Telangana Limited.
Distribution Utility Profile
TGNPDCL
Northern Power Distribution Company of Telangana Limited
Operational Jurisdiction
18 Districts CoveredGrid-connected solar net-metering applications and MRT meter testing for all administrative revenue circles in these districts are processed through TGNPDCL divisions:
Key Urban Centers
Warangal, Hanumakonda, Karimnagar, Nizamabad, Khammam, Ramagundam, Adilabad
Technical Feasibility & Specs
Interconnection norms & thresholds
Statutory supply voltages, transformer capacity ceiling, and bi-directional meter specifications applicable for solar rooftop connections under TGNPDCL.
Supply Voltage Thresholds
Permissible interconnection supply levels based on total solar inverter AC output capacity:
- LT Single-Phase
- Up to 5 kW (230V single-phase LT supply)
- LT Three-Phase
- Above 5 kW up to 56 kW (415V three-phase LT supply)
- HT 11 kV Supply
- Above 56 kW up to 1,000 kW (11 kV HT supply)
- HT 33 kV Supply
- Above 1,000 kW up to 5,000 kW (33 kV HT supply)
Supply conversion application can be bundled with solar feasibility filing.
Transformer & Load Caps
Statutory limits enforced by regulatory orders during technical scrutiny:
- DTR Capacity Ceiling: 50%
- Cumulative solar generation capacity on any distribution transformer cannot exceed 50% of the transformer rated capacity under TSERC Regulation 6 of 2016.
- Contracted Load Limit: Up to 100%
- Residential consumers may connect up to 100% of sanctioned load; commercial and industrial connections are capped at 80% of sanctioned load.
- Settlement Cycle
- Monthly net billing adjustment against retail tariff slabs
- Banking Carry-Forward
- Surplus energy credits carry forward across monthly billing cycles within the annual settlement period defined by TGERC tariff orders
Feasibility approval is valid for project execution and agreement signing.
Bi-Directional Net-Meter
Utility hardware specifications and calibration protocols:
- Bi-Directional Net Meter
- DLMS-compliant four-quadrant static bi-directional energy meter (Class 1.0 for LT, Class 0.5s for HT) conforming to IS 13779 / IS 14697 and CEA metering guidelines
- Solar Generation Meter
- Unidirectional static generation check meter installed on the inverter AC output
- Protocol Compliance
- DLMS / COSEM protocol compliant with optical communication port
- Testing Laboratory
- TGNPDCL Meter Relay Testing (MRT) Laboratory
Leo Solar handles procurement, lab testing delivery, and installation liaison.
Step-by-Step Workflow
4-Step Interconnection Timeline
From initial feasibility registration on the portal to grid synchronization and commissioning certificate release with TGNPDCL.
Online Application and Feasibility Verification
Registration on the TGNPDCL Solar Portal or PM Surya Ghar National Portal using USCNO. Local Assistant Divisional Engineer (Operation) assesses distribution transformer capacity and 11 kV feeder loading.
Feasibility Clearance and Agreement Execution
Receipt of formal technical feasibility sanction followed by execution of the standard Net Metering Interconnection Agreement with the TGNPDCL Divisional Engineer.
Installation and MRT Meter Testing
Turnkey rooftop installation including dedicated chemical earthing pits and surge protection. Delivery of meters to TGNPDCL MRT testing laboratory for bench calibration and official sealing.
Field Inspection, Grid Synchronization, and Commissioning
On-site technical inspection by TGNPDCL field engineers, verification of anti-islanding trip relay and earthing resistance (under 5 ohms), installation of sealed bi-directional meter, and issuance of Commissioning Certificate.
Regulatory & Technical Guidance
Frequently asked questions for TGNPDCL
Clear answers to common questions regarding distribution transformer headroom, billing adjustment, meter testing, and safety norms.
Can commercial establishments or agro-processing units in TGNPDCL apply for net-metering?
Yes. Commercial and industrial units under TGNPDCL can install grid-tied solar up to 80% of their sanctioned load under net-metering, subject to technical feasibility on the supplying 11 kV feeder or distribution transformer.
How does TGNPDCL calculate the 50% DTR capacity ceiling?
TGNPDCL monitors cumulative solar injection on each distribution transformer. Total installed rooftop solar capacity cannot exceed 50% of the transformer rated kVA. If the ceiling is reached, feasibility is deferred until the transformer is upgraded or capacity becomes available.
What earthing specifications are required by TGNPDCL for solar installations?
TGNPDCL mandates separate, dedicated chemical earthing pits for DC surge protection, solar module mounting structure frames, and inverter AC earth, with total earth resistance tested below 5 ohms.
How does net-metered billing reflect on the TGNPDCL consumer portal?
The monthly spot-billing system or smart meter logs import kWh, export kWh, and net kWh. The consumer portal and monthly bill itemize imported units, exported units, and carried-forward banked units.
Does TGNPDCL support three-phase conversion for solar rooftop installations?
Yes. If a single-phase consumer wishes to install a solar plant larger than 5 kW, they can apply for a single-phase to three-phase service conversion with TGNPDCL simultaneously with their solar feasibility request.
Full Liaison Included
Ready to connect solar to TGNPDCL?
Leo Solar handles your roof survey, structural design, online portal registration, MRT laboratory testing, and physical bi-directional meter synchronization with Northern Power Distribution Company of Telangana Limited.
Direct consultation with our Telangana & Andhra Pradesh utility engineering team.