This document discusses grid connectivity requirements and inspection procedures for solar photovoltaic rooftop (SPVRT) systems in India. It outlines applicable technical standards, interconnection specifications, component inspection checklists, functional safety checks, commissioning tests including unintentional islanding tests, and requirements for periodic interconnection tests. The document provides guidance on grid interconnection standards and procedures to ensure safe and reliable operation of SPVRT systems connected to the electric grid.

1. Presented by
USAID PACE-D TA Program
Sep-22
Grid Connectivity & Inspection Procedure
PARTNERSHIP TO ADVANCE CLEAN ENERGY-DEPLOYMENT (PACE-D)
TECHNICAL ASSISTANCE PROGRAM

2. Session: Contents
Applicable standards and regulations for grid connectivity of
SPVRT
Interconnection technical specifications and requirements
Component inspection checklist
Grid connected functional safety checklist

3. Session: Contents
Interconnection test specifications and requirements
Commissioning tests
Unintentional islanding functionality test
Periodic interconnection tests

4. Net Metering System without Battery

5. Net Metering System with Battery
Battery Bank
To dedicated
consumer loads

6. Applicable Standards & Regulations for Grid Connectivity of
SPVRT
 Central Electricity Authority (Technical Standards for Connectivity of the Distributed
Generation Resources) Regulations 2013
 IEEE 1547 – Standard for Interconnecting Distributed Resources with Electric Power
System, 2003
 Central Electricity Authority (Measures Relating to Safety and Electricity Supply)
Regulations, 2010
 Central Electricity Authority (Technical Standards for Connectivity to the grid)
Regulations 2007
 IEEE 519: Recommended Practice and Requirements for Harmonic Control in Electric
Power Systems, 2014

7. Interconnection Technical Specifications &
Requirements
General Requirements (IEEE 1547 / CEA Regulation 2013)
Voltage Regulations
The distributed resources shall
not actively regulate the
voltage at the point of
interconnection
Synchronization
The distributed resource
synchronized with electric
system shall not cause a
voltage fluctuation at the point
of interconnection greater than
±5%
Monitoring Provision
Each distributed resource of
250 kVA or more at a single
point of interconnection shall
have provisions for monitoring
its connections status, real
power output, reactive power
output and voltages at the
point of interconnection

8. Interconnection Technical Specifications &
Requirements
General Requirements (IEEE 1547 / CEA Regulation 2013)
Isolation Device
There should be a manually operating isolating switch between distributed generation resource
and electric system, which meets the following requirements:
 Allow visible verification that separation has been established
 Indicators to show clearly closed and open position
 Be readily accessible and be capable of being locked in open position
 May not be rated for load-break
 Be located at height of 2.44 m above ground level

9.  Depends on state grid code / SERC regulation
 Normal capacities and voltages:
 Capacity < 4 kW (or 5 / 6 / 7 / 10 kW in some states) connected at
240 VAC, 1φ, 50 Hz
 Capacity > 4kW (or 5 / 6 / 7 / 10 kW in some states) but < 50 kW
(or 75 / 100 / 112 kW in some states) connected at 415 VAC, 3φ, 50 Hz
 Capacity > 50 kW (or 75 / 100 / 112 kW in some states) < 1 MW
(or 2 / 3 / 4 / 5 MW in some states) connected at 11 kVAC, 3φ, 50 Hz
*The above mentioned ranges normally fall under grid codes for respective states
Interconnection Voltages

10. Interconnection Parameters - 1
Parameters Reference Requirement
Overall Grid
Standards
Central Electricity Authority (Grid Standard) regulations 2010 Compliance
Equipment BIS / IEEE / IEC Compliance
Meters
Central Electricity Authority (Installation and Operation of
Meters) Regulation 2006& Amendments thereof, OERC Generic
Tariff Order 2013
Compliance
Safety and Supply
Central Electricity Authority (Measures of Safety and Electricity
Supply) Regulation 2010
Compliance
Harmonic Current
IEEE 519 and CEA (Technical Standards for Connectivity of the
Distributed Generation Resources) Regulations 2013
shall not exceed the limits
specified in IEEE 519

11. Interconnection Parameters - 2
Parameters Reference Requirement
Synchronization
IEEE 519 and CEA (Technical Standards for
Connectivity of the Distributed
Generation Resources) Regulations 2013
Every time the generating station must be
synchronized to the grid. Voltage fluctuation < ±
5% at point of inter connection
Voltage
IEEE 519 and CEA (Technical Standards for
Connectivity of the Distributed
Generation Resources) Regulations 2013
Voltage-operating window should be under
operating range of 80% to 110% of the nominal
connected voltage. Beyond a clearing time of 2
second, the photovoltaic system must isolate
itself from the grid
Flicker
IEEE 519 and CEA (Technical Standards for
Connectivity of the Distributed
Generation Resources) Regulations 2013
Should not cause voltage flicker in excess of the
limits stated in IEC 61000

12. Interconnection Parameters - 3
Parameters Reference Requirement
Frequency
IEEE 519 and CEA (Technical Standards
for Connectivity of the Distributed
Generation Resources) Regulations 2013
When the Distribution system frequency deviates
outside the specified conditions (50.5 Hz on upper
side and 47.5 Hz on lower side), there should be
over and under frequency trip functions with a
clearing time of 0.2 seconds.
DC injection
IEEE 519 and CEA (Technical Standards
for Connectivity of the Distributed
Generation Resources) Regulations 2013
Should not inject DC power more than 0.5% of full
rated output at the interconnection point
Power Factor
IEEE 519 and CEA (Technical Standards
for Connectivity of the Distributed
Generation Resources) Regulations 2013
While the output of the inverter is greater than
50%, a lagging power factor of greater than 0.9
should operate

13. Interconnection Parameters - 4
Parameters Reference Requirement
Islanding and
Disconnection
IEEE 519 and CEA (Technical Standards for
Connectivity of the Distributed Generation
Resources) Regulations 2013
In the event of fault, voltage or frequency
variations the PV system must island /
disconnect itself within IEC standard on
stipulated period
Overload and Overheat
IEEE 519 and CEA (Technical Standards for
Connectivity of the Distributed Generation
Resources) Regulations 2013
The inverter should have the facility to
automatically switch off in case of overload or
overheating and should restart when normal
conditions are restored
Paralleling Device
IEEE 519 and CEA (Technical Standards for
Connectivity of the Distributed Generation
Resources) Regulations 2013
Paralleling device of photovoltaic system shall
be capable of withstanding 220% of the
normal voltage at the interconnection point.

14. Component Inspection Checklist
Sr. No. Item type Yes No
1 Installation Layout – is it as per drawing?
2 Inverter IS / IEC standards qualified
3 PV panel IS / IEC standards qualified
4 PV isolators / PV cables IS / IEC standards qualified
5
String level and cumulative protections are provided for over-current
and surges
6 AC disconnect manual switch provided with locking arrangement
7 Meters approved by concerned authority

15. Grid Connected Functional Safety Checklist
Sr. No. Item type Yes No
1
Check whether solar power generation stops automatically when DISCOM
supply shut off
2 Confirm Bi-directional flow recorded on net meter
3 Check ‘Consumption (Import) only’ mode operation
4 Check operation of Solar (Generation) meter
5 Check all Protections and Earthing points
6
Confirm Solar and Bi-directional meter tested & sealed by DISCOM meter
testing lab

16. Commissioning Tests
 All commissioning tests shall be performed based on written test procedures of equipment
manufacturer / system integrator
 A visual inspection shall be made to ensure that the system earthing is adequate as per
standard / regulation
 A visual inspection shall be made to confirm the presence of the isolation device as required
by standard / regulation
 The following initial commissioning tests shall be performed on the installed solar PV
rooftop system and grid connected inverter prior to the initial parallel connection to the
grid:
 Operability test on the isolation device
 Unintentional islanding functionality
 Cease to energize functionality

17. Unintentional Islanding Functionality Test
If there is more than
one inverter, tests
should be carried out
for each inverter
SPVR system should
produce more than
20% of the rated
output of the SPVRT
Array or the inverter –
whichever is less
This test must be
conducted during
noon time on a sunny
day

18. Unintentional Islanding Functionality Test – Test 1
Test 1: Inverter must cease supplying power within 0.2 seconds of loss of mains
Step 1:
Keep DC supply from the SPVRT array connected to the inverter
Step 2:
Place the voltage probe in the inverter side of the AC main switch
Step 3:
Turn OFF the main switch, through which inverter is connected to grid
Step 4:
Measure time taken for inverter to cease attempting to export power with a
timing device and record

19. Unintentional Islanding Functionality Test – Test 2
Test 2: Inverter must not resume supplying power until mains have been
present for more than 60 seconds
Step 1:
Keep DC supply from the SPVRT array connected to the inverter
Step 2:
Place the current probe in the inverter side of the AC main switch
Step 3:
Turn ON the main switch, through which inverter is connected to grid
Step 4:
Measure time taken for inverter to re-energize and start exporting power with
a timing device and record

20.  All interconnection related protective functions and associated batteries shall be
periodically tested at intervals specified by the manufacturer, system integrator or the
authority who has the jurisdiction over the DR interconnection
 Periodic test reports should be maintained
Periodic Interconnection Tests

21. Quiz: Fastest Finger First

22. 25
Anurag Mishra
Senior Clean Energy Specialist
USAID/India
Email: amishra@usaid.gov
Disclaimer:
This training material is made possible by the support of the American
People through the United States Agency for International Development
(USAID). The contents of this material are the sole responsibility of
Nexant, Inc. and do not necessarily reflect the views of USAID or the
United States Government. This material was prepared under Contract
Number AID-386-C-12-00001.