Introduction:

These guidelines are issued  as  per  Regulation  for  connectivity  with  the  Grid and sale of electricity from the Roof- top Solar  Photovoltaic  System,  viz., Telangana State Electricity Regulatory Commission (Net Metering Rooftop Solar PV Grid Interactive Systems) Regulation,  2016  [Regulation  No.6]  which  came into force from the date of its notification in the Telangana Official Gazette on 23.11.2016 and these guidelines are also effective from 23.11.2016.

Eligibility of consumer and project capacity:

1. Eligible Consumer is a consumer of electricity in  the  area of supply of the DISCOM, who uses or proposes to use a Rooftop Solar PV System, which can be self-owned or a third party owned to offset a part or all of the consumer’s own electrical requirement including a consumer catering to a common load such as common services in a Housing Society.
   1. The land will be Own or be in legal possession of the premises including the rooftop or terrace or elevated areas on land, building or infrastructure or part or combination thereof on which the Rooftop Solar PV System is proposed to be installed.
   1. An Eligible Consumer shall be in three phase service, a single phase consumer is also eligible for net metering upto 5 KW.
   1. The maximum Rooftop Solar PV System capacity to be installed at any Eligible Consumer’s premises shall be as under:

Sl	Type of Consumer	Maximum allowable Rooftop Solar
No.	PV System capacity to be installed
1	Residential and	100 % of the consumer’s
Government	sanctioned load
2	Industrial, Commercial	80 % of the consumer’s sanctioned
and Other Consumers	load

(Note: Rooftop Solar PV System installed capacity shall not be less than 1 kWp and shall not exceed 1 MWp)

• Consume the entire electricity generated from  the  Rooftop  Solar  PV System at the same premises wherein it is installed and  generating  the solar power.
  • An Eligible Consumer may install or enhance the capacity of, or upgrade the Rooftop Solar PV Systems at different locations within the same premises that the total capacity of such Systems within the same premises shall not exceed the individual capacity limits mentioned at Para II.(d) above.
  • An Eligible Consumer intending to install a Rooftop Solar PV System having capacity in excess of 75 kW and up to 1 MW can connect to 11 kV or 33 kV feeder from which the feeder of an Eligible Consumer is availing of supply of power.

Procedure for Application, Registration and approval:

An Eligible Consumer who proposes to install a Rooftop Solar PV System has to follow the below procedure either in offline mode or in online mode:

1. Offline Mode:
   1. Solar Net Metering Rooftop Application form (Annexure I) is available in the Discom website www.tssouthernpower.com/ www.tsnpdcl.in, the same to be downloaded and filled application to be submitted at the concerned Consumer Service Center (CSC)/Integrated Consumer Service Center (ICSC).
   1. The necessary documents to be enclosed along with application form are as given below:
      1. Copy of latest Electricity Bill.
      1. Demand Draft drawn with applicable fee in favour of “Discom (TSSPDCL or TSNPDCL)”.
      1. 2 No’s Self-addressed Rs.5/- Stamped envelopes.
   1. Applicable fee:

System size	Applicable fee per connection
For all LT consumers	Rs.2,500/-
For all HT consumers	Rs.15,000/-

• The  CSC/ICSC  shall  register  the  application  and  acknowledge   the receipt of the application with a unique registration number for further reference.

Online Mode:

1. Login to DISCOM website www.tssouthernpower.com/ www.tsnpdcl.in, and select the “Service Registration” tab, and proceed for  further process.
   1. Eligible Consumer has to pay the application fee of  Rs.2500/-  for  LT service and Rs.15,000/- for HT service through  online  payment  mode. After successful payment a registration number will be generated, which shall be noted down for further correspondence with the Discom.

Further process after successful submission of application:

1. The nodal point of contact for the Solar Net Metering programme shall be the local Divisional Engineer (Operations).
   1. The Submitted Solar Net Metering Rooftop Application by consumer at CSC/ICSC/Online mode  will  be  forwarded  to  Assistant  Divisional Engineer (ADE)/(Operation) if the consumer is under LT Category, Or to Divisional Engineer (DE)/(Operation) if the consumer is  under  HT Category.
   1. The concerned ADE (Operation) Or  DE  (Operation)  shall  provide  a written notice that they have received all the documents required for the interconnection point  or  furnish  the  deficiencies  in  the  application within seven (7) working days.
   1. The concerned ADE (Operation) Or DE (Operation) shall assess (refer point number IV for capacity limits  of DTR, 11 kV and 33 kV feeder in this guidelines) the feasibility of interconnection point and the relevant distribution transformer capacity and/or relevant 11 kV/33 kV feeder capacity (in case of HT consumer) and communicate the feasibility

(Annexure-II(a) for HT and II(b) for LT) to the Eligible Consumer within Twenty One (21) working days from  the  receipt  of  proper  application. Any application not acted up within Twenty One (21) working  days from the date of receipt shall be deemed to have been approved.

• The feasibility so communicated shall be valid for a period of four (4) months, unless extended by the concerned ADE (Operation) Or DE (Operation) for a reasonable cause. The extended validity period of feasibility shall not exceed a period of Ten (10) months including the extended time from the date of first feasibility communication.
  • While communicating any deficiencies in the feasibility for the connection of Rooftop Solar PV System, the concerned ADE (Operation) Or DE (Operation) shall communicate the Eligible Consumer (Annexure– II(c) for HT and II(d) for LT):
    • Particulars of deficiencies with reference to interconnection of the proposed Rooftop Solar PV System with the Distribution System;
    • Cost estimate for removal of such deficiencies including augmentation of the transformer/distribution system, if required.
  • The Eligible Consumer shall pay the estimated amount within Fifteen

(15) days of receipt of such communication. If the estimated amount not paid by the Eligible Consumer within Fifteen (15) days from the date of receipt of such communication to the Eligible Consumer, the application shall stand cancelled and the application fee shall be forfeited.

• If approval cannot be  granted  due  to  inadequate  Distribution Transformer capacity or 11 kV / 33 kV Feeder capacity (in case of HT consumer), the application may be considered, in chronological order of seniority and if the consumer so opts, after such  capacity  becomes available.
  • On receipt of the estimate amount, the concerned ADE (Operation) Or DE (Operation), shall promptly remove the deficiencies in the distribution     system                                        including        augmentation   of                                         the transformer/distribution network within Fifteen (15) days. Provided the augmentation of the system shall be in accordance with the time period specified in the Standards of Performance (SoP) notified by the Commission from time to time, if the period exceeds Fifteen (15) days as provided above.
  • On removal of such deficiencies including augmentation of distribution transformer/distribution network, the concerned ADE (Operation) Or DE (Operation) shall immediately convey the approval for interconnection of the proposed Rooftop Solar PV System to the Eligible Consumer. A copy of such approval shall also be forwarded to the State Nodal Agency (TSREDCO) and the Chief Electrical Inspector for necessary action at their end.
  • The Net metering connection agreement (Annexure-III) as devised shall be executed by the Eligible Consumer with the DISCOM within Fifteen (15) days of receipt of the technical feasibility approval.

• Feasibility study and inspection shall be the responsibility of ADE (Operation) in case of LT services and DE (Operation) in case  of  HT services.

Capacity limits of Distribution Transformer, 11 kV and 33 kV Feeder level:

1. The concerned ADE (Operation) Or DE (Operation) shall ensure the following capacity limits before issue of technical feasibility for Net metering arrangement to an Eligible Consumer:

Sl	Consumer	DTR/	Maximum allowable	Maximum allowable
No	Voltage level	11 kV or	cumulative capacity	cumulative
		33 kV	of all the Rooftop	capacity in kW/MW
		feeder	Solar PV Systems
			permitted of its
			rated capacity/max
			load
1	Low Tension	DTR	50 %	50% of existing DTR
(LT)	capacity x 0.9 pf
2	High Tension	11 kV or	50 %	1.125 MW (11 kV)
(11 kV / 33	33 kV
4.5 MW (33 kV)
kV)	feeder

1. the Net Metering connectivity exceeding 50% of such rated capacity may allow upon consideration of a detailed load study carried out duly taking prior approval from Chief General Manager/Commercial.
2. the capacity available on each Distribution Transformer and 11  kV feeder of a substation and 33 kV feeder for connecting the Rooftop Solar PV Systems under the Net Metering arrangements has to be uploaded in Discom website for ready reference to the interested consumer. Hence, it is requested to provide the information required to the Chief General Manager/Commercial.
3. Thereafter, update the Distribution Transformer-wise, 11 kV feeder-wise and 33 kV feeder-wise capacity available and the cumulative capacity of the Rooftop Solar PV Systems installed under the Net Metering arrangements quarterly and provide the information to the Chief General Manager to place in Discom website in the month following the close of the relevant quarter.

Synchronization with the Distribution Network/Grid: Standards and Safety:

1. The Eligible Consumer shall submit work completion report as mentioned in Annexure–IV and shall make a request for inspection. The concerned ADE (Operation) for LT services or concerned DE (Operation) for HT services shall inspect the system within 10 working days and provide approval. In absence of the response within the stipulated time, it shall be considered as deemed inspection approval.
   1. The ADE (Operation) & ADE (Meters & Protection) for LT services Or DE (Operation)  &  DE  (Meters  &  Protection  )  for  HT  services  shall   ensure while the inspection that  the  inter-connection  of  the  Rooftop  Solar  PV System with  its  Network  conforms  to  the  specifications,  standards  and other provisions specified by the Central Electricity Authority (CEA) in (Technical Standard for Connectivity  of  the  Distributed  Generation Resources) Regulations, 2013, the CEA (Measures relating to  Safety  and Electric  Supply),  Regulations,  2010  and   the   State   Grid   Code,   Provided that a variation in the rated capacity of the system within a range  of  five percent (5%) shall be allowed.
   1. A Solar Rooftop PV system should qualify the technical requirements for the grid interconnection with the network of the DISCOM and it shall be separately grounded / earthed.

1. Harmonic Injection:- CEA’s (Technical Standards for Connectivity of the Distributed Generation Resources) Regulations, 2013:

–          IEEE  519  (2014),  “Recommended  practice  and requirements for harmonic  control  in  electric  power systems

1. Flicker: Operation of Photovoltaic system shouldn’t cause voltage flicker in excess of the limits stated in the relevant sections of

–           IEC 61000 series

1. Power Factor: While the output of  the  inverter  is  greater  than 50%, a lagging power factor of  greater  than  0.9  should  operate duly complying

–          IEC 61215. 2nd Ed, (2005-04)

–          IEC 61646. 2nd Ed, (2008-05)

–          IEC 62108. 1st Ed, (2007-12)

–          IEC 61730-1, Ed. 1.2 (2013-03)

–          IEC 61730-2, Ed. 1.1 (2012-11)

• Any alternate source of supply shall be restricted to the consumer’s network and the consumer shall be responsible to take adequate safety measures to prevent battery power or diesel generator power or back-up power extending to the distribution licensee’s LT / HT grid on failure of the distribution licensee’s grid supply. Safety measures may include isolation of net metering arrangement from the grid
• The Discom shall have the right to disconnect the Rooftop Solar PV System of an Eligible Consumer from its system at any time on the following situations / conditions:
  • Emergencies or maintenance requirement of the distribution electric system;
  • Hazardous conditions existing on the distribution system due to operation of the Rooftop Solar PV System or the protective equipment as determined by the Discom/ TSTRANSCO / State Load Dispatch Centre (SLDC);
  • Adverse electrical effects, such as power quality problems, on the electrical equipment of other consumers of the  distribution caused by the Rooftop Solar PV System as determined by the Discom.
• The Rooftop Solar PV System should be capable of detecting an unintended island condition and must have an anti-islanding protection to prevent any unfavourable conditions including failure of supply. IEC 61727, 2nd Ed. (2004) &  IEC 62116, 2nd  Ed. (2014-02) shall be  followed to test the island prevention measure for the grid connected photovoltaic inverters.
• Every Rooftop Solar PV System shall be equipped with the automatic synchronization device, provided that the Rooftop Solar PV System using the inverter shall not be required to have a separate synchronization device, if the same is inherently built into the inverter.
• The Rooftop Solar PV System operating in parallel with the electricity system shall be equipped with the following protective functions to sense the abnormal conditions on the electricity system and cause the Rooftop Solar PV System to be automatically disconnected from the electricity system or to prevent the Rooftop Solar PV System from being connected inappropriately to the electricity system;

1. Over and under voltage trip functions if  voltage  reaches  above 110% or below 80% respectively with a clearing time upto two (2) seconds;
   1. Over and under frequency trip functions, if frequency reaches

50.3 Hz or below 49.2 Hz with a clearing time upto 0.2 seconds;

1. The Rooftop Solar PV System shall cease to energize the circuit to which it is connected in case of any fault in the circuit;
   1. A voltage and frequency sensing  and  time  delay  function  to prevent the Rooftop Solar PV System from energizing  a  de- energized circuit and to prevent the Rooftop Solar PV System from reconnecting with the electricity system unless voltage  and frequency is within the  prescribed  limits  and  are  stable  for  at least sixty (60) seconds; and
   1. A function to prevent the Rooftop Solar PV System from contributing to the formation of an unintended island and ceases to energize the electricity system within two (2) seconds of the formation of an unintended island.
2. The equipment of the Rooftop Solar PV System shall meet the following safety requirements:
   1. Circuit Breakers or other interrupting equipment shall  be suitable for their intended application with  the  capability  of  interrupting the maximum available fault current expected at their location,
   1. The Rooftop Solar PV  System  and  the  associated equipment  shall be so designed that the failure of any single device or component shall not potentially compromise the safety and reliability of the electricity system and
   1. Paralleling device  of the  Rooftop Solar PV System shall  be  capable of withstanding 220% of the  nominal  voltage  at  the interconnection point.
3. Every time the Rooftop Solar PV System of the Eligible Consumer is synchronized with the distribution system, it shall not cause the voltage fluctuation greater than ± 5% at the point of inter connection.
4. After considering the maintenance and the safety procedures,  the concerned Assistant Divisional Engineer(Operations) Or Divisional Engineer(Operations) may require an Eligible  Consumer  of  a  Rooftop Solar PV System  to  provide  a  manually  operated  isolating  switch between the Rooftop Solar PV System and the  electricity  system, which shall meet following requirements:
   1. Allow visible verification that separation has been accomplished;
   1. Include indications to clearly show open and closed positions;
   1. Be capable of being reached quickly and conveniently twenty four

(24) hours a day by the DISCOM personnel without requiring the clearance from the Eligible Consumer;

1. Be capable of being locked in the open position;
   1. May not be rated for load break and may not have a feature of over-current protection; and

• Be located at a height of at least 2.44 meter above the ground level.
• Prior to synchronization of the Rooftop Solar PV System for the first time with the distribution system, the Eligible Consumer and the concerned Assistant Divisional Engineer (Operations) & Assistant Divisional Engineer (Meter & Protection) for LT Services and Divisional Engineer (Operations) & Divisional Engineer (Meter & Protection) for HT services shall agree on the protection features and the control mechanism.
• The power conditioning unit shall have the features of filtering out harmonics and other distortions before injecting the energy into the distribution system. The Total  Voltage  Harmonic  Distortion  (THD)  shall be within the  limits specified in the  Indian  Electricity Grid Code (IEGC). The  technical  standards,  power  quality  standards  and   inverter standards shall be followed by Eligible Consumer in  line  with  the standards as specified by the CEA from time to time.

Net Metering arrangement

1. A single bi-directional meter shall be installed for recording of export and import energy. This bi-directional meter should have the following characteristics:
   1. The rated capacity of Bi-Directional meter should be according to the sanctioned load / contracted demand of  the consumer with the DISCOM.
   1. Separate registers for export and import with the Meter Reading Instrument (MRI) downloading facility.
   1. kVAr, kWh, kVA , kVAh measuring registers for capacity above 10 kW.
   1. Advanced Metering Infrastructure (AMI) facility with RS232 (or higher) communication port.
   1. Class 1 accuracy meters for Rooftop Solar PV Systems up to  10 kW, 0.5 accuracy class meters for Rooftop Solar  PV  Systems above 10 kW and 0.2 class accuracy meters for High Tension (HT) systems (56 kW and above).
   1. Meters should be certified by the Bureau of Indian Standards (BIS).
   1. Current Transformer (CT) functionality meters for the Rooftop Solar PV Systems above 56 kW.
   1. Providing of Net Meter in the premises of the Eligible Consumer is the responsibility of DISCOM.
   1. Provided that where the Eligible Consumer is within the ambit of Time- of-Day (ToD) Tariff, the Net Meter installed shall be capable of recording ToD consumption and generation.
   1. Provided further that an Eligible Consumer may opt to procure, at his cost, after testing the Net Meter is to be installed.
   1. The Net Meter and the Solar Generation Meter shall be installed at such locations in the premises of the Eligible Consumer as would enable easy access to the departmental personnel for meter reading.
   1. If everything found in line with the guidelines, the concerned officials

should synchronize the Solar Rooftop PV System to the grid and sign the Synchronization report/Test report (Annexure–V(a) for HT services Or Annexure–V(b) for LT services) and forward the Synchronization report/Test report to the concerned Circle Office Or Electricity Revenue Office for billing purpose duly updating the same in CSC login.

Energy Accounting and Settlement

1. The accounting of electricity exported and imported by the Eligible Consumer shall become effective from the date of connectivity of the Rooftop Solar PV System with the distribution Network.
   1. For each Billing Period, the following parameters shall show separately:-
      1. The quantum of electricity Units exported by the Eligible Consumer;
      1. The quantum of electricity Units imported by the Eligible Consumer;
      1. The net quantum of electricity Units billed for payment by the Eligible Consumer;
      1. The net quantum of electricity Units carried over to the next Billing Period; and
      1. Provided that if the quantum of electricity exported exceeds the quantum imported during the Billing Period, the excess quantum shall be carried forward to  the  next  Billing  Period  as  credited Units of electricity and the Eligible Consumer shall get a monthly minimum bill;
      1. Provided further that if the quantum of electricity Units imported by the Eligible Consumer during any Billing Period exceeds the quantum exported, then invoice shall raise for the net electricity consumption after adjusting the credited Units of electricity
      1. There shall be no deemed generation  charges  payable  to  the Eligible Consumer or the third party owner of the PV solar rooftop system
      1. The billing period and the due date of the bills shall be the same as that of the Eligible Consumer in whose premises the solar system has been installed.
   1. The unadjusted net credited Units of electricity shall be settled twice in a year viz., in June and December. The net export units credited for the six month period shall be settled at its average cost of power purchase as approved by the Commission for that year or at a rate as notified by the Commission from time to time. The sum so arrived shall be either adjusted in the next month electricity bill or deposited in the bank account of the Eligible Consumer furnished at the time of filing of the application.
   1. Provided that at the beginning of each of the Settlement Period, the cumulative quantum of injected electricity carried forward shall be re-set to zero.
   1. Where an Eligible Consumer is within the ambit of Time of Day (ToD) tariff, the electricity consumption in any time block, i.e. peak hours, off- peak hours, etc., shall be first compensated with the quantum of

electricity injected in the same time block. Any excess injection over and above  the  consumption in any other time  block in a Billing Cycle shall be accounted as if the excess injection had occurred during off-peak hours.

• The Eligible Consumer shall have recourse, in case of any dispute regarding the billing.
  • In case the applicable tariff provides for billing on kVAh basis, the net drawl or injection of energy shall also be measured in kVAh.
  • When an Eligible Consumer cancels the Net metering Agreement entered into with the DISCOM after giving a month’s notice, then, unused electricity credits shall be paid at a rate of Rs 0.50/kWh by the DISCOM or at a rate as notified by the Commission from time to time and ceases to be an Eligible Consumer thereafter.

Applicability of other charges and incentives:

1. The Rooftop Solar PV System under the net metering arrangement, whether self-owned or third party owned installed on the Eligible Consumer’s premises, shall be exempted from Transmission Charge Transmission Loss, Wheeling Charge, Wheeling Loss, Cross Subsidy Surcharge and Additional Surcharge.
   1. All incentives or subsidy provided by  the  Government  of  India  through the Ministry of New and Renewable Energy (MNRE) under the National Solar Mission or  other  schemes  and  any  incentive  or  subsidy  provided by the Government of Telangana state from time to time shall belong to the Eligible Consumer or  on  authorization  of  the  Eligible  Consumer  to the vendor of the Rooftop Solar PV system and can be claimed after installation of the Rooftop Solar  PV  power  net  metering  arrangement from the State Nodal Agency.
   1. An Eligible Consumer or a vendor of the Rooftop Solar PV system on authorization from an Eligible Consumer shall produce the latest net metering bills for two months raised by a DISCOM for the release of the subsidy or incentive. These bills shall be counter signed by the concerned Divisional Engineer (Operation) and the District Manager of the State Nodal Agency (TSREDCO). The Nodal Agency shall make the payment of subsidy or incentive within thirty (30) working days of the receipt of claim of subsidy/incentive.

Inspection by DISCOM Officials:

1. The Discom Officials on inspection at the time of according permission to install the net metering arrangement or at any time thereafter, finds that, the Eligible Consumer has installed equipment not confirming to the standards published by the International Electro-Technical Commission (IEC) or Bureau of Indian Standards (BIS) as a part of the net metering arrangement in the consumer’s premises, the vendor of the equipment shall be blacklisted and the same shall be notified to the MNRE and the State Nodal Agency. Further, the Discom  Officials reserves the right to withdraw the permission to the net metering arrangement and cancel the net metering agreement with the Eligible Consumer after giving an opportunity in writing.
   1. The Eligible Consumer shall  install  any  additional  equipment  or additional Solar panels after obtaining prior permission in writing from the DISCOM, failing which, the Discom Officials may cancel the Net Metering Agreement after giving an opportunity in writing.

Sharing of Clean Development Mechanism (CDM) benefits

The Eligible Consumer shall retain  the entire  proceeds of CDM  benefits  in  the first year after the date  of  commercial  operation  of  the  generating  station.  In the second year, the share of  the  Distribution  Licensees  shall  be  10%  which shall be progressively increased by 10% every year till it  reaches 50%,  where after, the proceeds shall  be  shared  in  equal  proportion  by  the  Eligible Consumer and the DISCOM.

• Restriction and Control (R&C) Measures

In the event of the DISCOM being directed to impose Restriction and Control (R&C) measures under section 23 of the Act, the Discom Officials shall not refuse injecting of solar power generated from a Rooftop Solar PV System installed by the residential and the government consumers.

Energy Accounting during Meter defects

In case of failure of the meter recording export of energy, the meter shall be replaced within fifteen (15) days of the  notice  of  the  failure.  The  number  of units to be billed during the period in which the meter ceased to function or became defective, shall be determined by taking the average of the electricity exported during the preceding three (3) billing cycles  to  the  billing  cycle  in which the said meter ceased to function or became defective provided that the condition with regard to export of electricity during the said three  (3)  billing cycles was not different from that which  prevailed  during  the  period  in  which the Meter ceased to function or became defective.

Compensation

In case of failure of the net metering arrangement, compensation shall be payable as per the provisions of the Telangana State Electricity Regulatory Commission (Licensees’ Standards of Performance) Regulation, 2016 as amended from time to time.