Government of Nepal Ministry of Environment, Science and Technology Alternative Energy Promotion Centre

Government of Nepal Ministry of Environment, Science and Technology Alternative Energy Promotion Centre Nepal Interim PV Quality Assurance (NIPQA) 2005 (Second Revision of NIPQA - 2000) October 2005

1 PREAMBLE NEPAL INTERIM PV QUALITY ASSURANCE (NIPQA) December 2000 First Revision: November 2002 Second Revision: September 2005 This technical standard for components of a Solar Photovoltaic (PV) System called Nepal Interim Photovoltaic Quality Assurance (NIPQA) was first developed and adopted by Alternative Energy Promotion Centre/Energy Sector Assistance Programme (AEPC/ESAP) in December 2000 for dissemination of SHS under ESAP. This interim standard was needed due to absence of Nepal Standard (NS) for the components used in PV systems. AEPC/ESAP used the standard to test Solar Home System (SHS) components at the Solar Energy Test Station (SETS) established with investment and technical assistance from AEPC/ESAP and hosted by Royal Nepal Academy for Science & Technology (RONAST). Nepal Bureau of Standard & Metrology (NBSM) and Solar Electric Manufacturers Association Nepal (SEMAN) are the other two promoters of SETS. After two year of its use it was revised in November 2002 through a participatory process. The NIPQA is again revised in September 2005 after two and half year of use and intensive consultations with stakeholders. While the first drafting and first revision had inputs from external consultants, the second revision was done with inputs entirely from within the country. NIPQA has two categories of parameters. The first category is the mandatory parameters for compliance or failure and second category is the recommended ones. The recommended parameters are primarily for quality enhancement through product development. The second revision attempted to incorporate standards for components of larger PV systems (ISPS and PVPS). The second revision dropped the system sizing part entirely to be taken up in separate system sizing guidelines. The second revision also makes the document a national one in contrary to what it started as a standard for one programme. The next step in the process could very much be transforming NIPQA to NS. 2/13

2 DEFINITIONS 1. A "Solar Home System" (hereinafter called SHS) is a photovoltaic system used for domestic purposes for providing primarily lighting services. Additional services such as information and entertainment through DC television sets or radios as well as DC fans may also be provided in addition to lighting. 2. An Institutional Solar PV System (hereafter called ISPS) is a DC or AC photovoltaic system used for lighting and power supply to appliances like computer, telephone, refrigerator, etc., in public institutions like VDC buildings, schools, health posts, religious buildings, clubs, etc. 3. A Photovoltaic Pumping System (hereafter called PVPS) is a DC or AC photovoltaic water pumping system operated by photovoltaic electricity to lift water for drinking and drip irrigation purposes. 4. Insolation: Intensity of sunlight measured in kilo-watt-hours in a square metre area in a day (kwh/m 2 /day). 5. Autonomy Days (N): Maximum number of consecutive days where the daily load can be fulfilled without charging the battery, starting the first day with a fully charged battery. 6. Discharge rate: The discharge rate of the battery is expressed as a ratio of the nominal battery capacity to the discharge time period in hours until the final or end voltage of the battery is reached. The usual discharge rates are C 20 or C 10 or C 5. 7. Watt Peak (Wp): Wattage generated by a PV module under a Standard Test Condition (STC) 8. Depth of Discharge (DoD): This is the measure of state of discharge of a battery, where 100% DoD corresponds to a fully discharged battery. 9. State of Charge (SoC): The level of Ampere-hours remaining in the battery until 100% DoD, relative to the C 20 capacity. 10. STC: Standard Test Condition is defined as 1,000 W/m 2 solar radiation in the plane of the array, 1.5 air-mass ratio and 25 o C cell temperature. 11. Critical indicators in charge controller: The indicators displaying the status of battery charging from PV module, normal and low battery charge level. 3/13

3 MINIMUM REQUIREMENTS OF COMPONENTS 3.1 PV Module 3.1.1 Compulsory: 1. The PV module must be of the Crystalline Silicon Type or the Thin-film Type. Both types of modules need to be certified by a third party agency as per details below: Crystalline silicon PV modules according to the standard - "IEC 61215 - Crystalline Silicon Terrestrial Photovoltaic (PV) Modules - Design Qualification and Type Approval" or the IEC equivalent national, regional or international standards Thin-film PV modules according to the standard - "IEC 61646 - Thin-film Terrestrial Photovoltaic (PV) Modules - Design Qualification and Type Approval" or the IEC equivalent national, regional or international standards The IEC equivalent national, regional or international standard must include test of all the IEC certification parameters as per the codes IEC 61215 or IEC 61646. The national, regional or international testing laboratory must be accredited by the concerned Government body or IEC. 2. A nameplate must be mounted on the PV module frame containing the following details: Brand and name of the manufacturer Model Manufacturer s serial number Maximum power in Watt Peak Open circuit voltage in Volt Short circuit current in Ampere Maximum rated voltage in Volt Maximum rated current in Ampere 3. Electrical parameters of PV Module The deviation of maximum power from its nominal values stated by the manufacturer must not exceed the limit of -10% to +20% (minus 10% to plus 20%) at STC The maximum rated voltage (V mp ) must be at least 16 Volt at STC 4. The PV module of size 40Wp or above must have inbuilt bypass diodes. The modules of any rating to be used for ISPS and PVPS applications must have by pass diodes. 5. The warranty period of Solar PV Module must be at least 10 years against maximum 10% reduction in output power at STC. 3.2 Battery 3.2.1 Compulsory: 1. The battery must be deep cycle type of following categories. 4/13

a. Vented (open) lead acid battery Flooded Flat plate Tubular plate b. Sealed (valve regulated) lead acid battery Absorbed Glass Mat Gel Flat plate Flat plate Tubular plate 2. The self-discharge of the batteries at 25 C must not exceed 4% of their rated capacity per month (30 days). 3. The operational life cycle of 12 V or 6 V or 2 V battery for flat and tubular plate type must be as follows: For flat plate type, the operational life cycle of 12 V or 6 V battery must be at least 1,800 cycles at 20% DoD and 250 cycles at 80% DoD. For tubular plate type, the operational life cycle of 12 V or 6 V battery must be at least 3,000 cycles at 20% DoD and 1,000 cycles at 80% DoD. For flat plate type, the operational life cycle of 2 V battery must be at least 3,000 cycles at 20% DoD and 1,000 cycles at 80% DoD. For tubular plate type, the operational life cycle of 2 V battery must be at least 3,600 cycles at 20% DoD and 1,200 cycles at 80% DoD. 4. The deviation of battery capacity from its rated capacity stated by the manufacturer must not exceed the limit of -10% to +10% (minus 10% to plus 10%) within 5 cycles of test. 5. The following minimum information must be included in the label of the battery: Brand and name of the manufacturer Model and type Rated capacity in Ampere-hours at the discharge rate C 20 or C 10 or C 5 Nominal voltage in Volt 3.2.2 Recommended: 1. The amount of electrolyte should exceed 1.15 litre per cell per 100 Ah nominal capacity at C 20 (20 hours nominal capacity). 2. The initial density of electrolyte to be used in battery should not exceed 1.25 g/cl at 25 o C. 3. The battery should have terminal caps to protect battery terminals from short circuit. 4. ISPS batteries can be installed in series in order to obtain the required DC Voltage for inverter but, 5/13

Voltage drop in interconnecting wire should be less than 0.5% of rated voltage. Array of battery should be formed with perfectly matching battery. 5. The battery acid should be certified according to NS standard. 6. The battery water (distilled or de-mineralised or de-ionised water) should be certified according to NS standard. 3.3 Lamp 3.3.1 Compact Fluorescent Lamp (CFL) or Tubular Lamp (TL) 3.3.1.1 Compulsory: 1. Luminous yield of the total ballast and fluorescent lamp system must be at least 35 lumens/watt within 15 minutes warm up time after switching on. 2. Reduction in the output (reference lumen) must not exceed 10% after 1,000 on/off cycles and must not exceed 50% after 5,000 on/off cycles. 3. Ballasts must ensure safe and regulated ignition within 10 seconds in the voltage range from 10.3 to 15V over temperature range of 5 o C to +40 o C. 4. The electrical efficiency of the lamp (ballast and tube combined) must be at least 70% at 12 Volt. 5. The lamp must be protected against reverse polarity. 6. Standby consumption (in no-tube condition) of ballast must be less than 20% of rated or nominal capacity (power consumption). 7. The lamp must be operational at an ambient temperature range of 5 o C to +40 o C. 8. The following minimum information must be included in the label of the lamp: Brand name and model Solar PV company name Nominal power in Watt Permitted tube size(s) in Watt Nominal voltage in Volt Size of fuse(s) in Ampere (if applicable) 3.3.1.2 Recommended: 1. The DC component of the current through the fluorescent lamp should be zero. 2. The lamp electronics should not produce radio frequency interference greater than 50 mv/m under any operating circumstances within 2 metres distance. 3. There should not be any voltage spikes on the output wave-shape at the tube terminal. The maximum crest factor should be less than 2.0 over the voltage range from 11V to 12.5V at an ambient temperature of 25 o C 6/13

4. The lamp enclosure (housing) should display good workmanship and should provide protection against dust, water, oil, and smoke. 3.3.2 Tube for Compact Fluorescent Lamp (CFL) or Tubular Lamp (TL) 3.3.2.1 Compulsory: 1. Tube for compact fluorescent lamp (CFL) or Tubular Lamp (TL) must fulfil criteria 1-7 1 mentioned in clause 3.3.1.1. 3.3.3 LED Cluster Lamp 3.3.3.1 Compulsory: 1. The luminous intensity of individual low power single WLED must not be less than 6000 mcd per WLED at a viewing angle greater than or equal to 2 x 15 o. 2. The luminous intensity of individual high power single WLED must produce at least 6000 mcd of luminous intensity per 100 mw power input at a viewing angle greater than or equal to 2 x 15 o. 3. The luminous efficiency of each individual WLED lamp or cluster of WLEDs must not be less than 15 Lumen/watt within 15 minutes warm up time after switching on. 4. The WLED lamps must be operational for at least 10,000 cycles with reduction in luminous efficiency not exceeding 5% of its initial value (15 Lumen/watt). 5. The lamp must be protected against reverse polarity. 6. The following minimum information must be included in the label of the WLED lamp: Brand name, type (Single or clustered WLED) and model Solar PV company name Nominal power in Watt Nominal voltage in Volt Size of fuse(s) in ma (if applicable) 7. For portable WLED lamps, the combined resistance of wires, switches, sockets (between battery terminals and WLEDs) must not exceed 10 milli Ohms. 8. If more than one WLED is used in lamp assembly, parameters (current and luminous intensity at specified voltage) of individual WLEDs used in the lamp must not differ by more than 10%. 3.3.3.2 Recommended: 1. To protect eyes from localised light, proper diffusion system should be incorporated so as to achieve almost uniform light intensity over a solid angle of at least 45 o. 1 The company must provide the ballast for tube testing. 7/13

2. The continuous operating life of the WLEDs should not be less than 50,000 hours and it has to be substantiated by the WLED manufacturer s claim sheet. 3. The Colour Rendering Index (CRI) of the WLEDs should be not less than 60. 4. The lamp enclosure (housing) should display good workmanship and should provide protection against dust, water, oil, and smoke. 3.3.4 Lamps used in Solar Lanterns 3.3.4.1 Compulsory: 1. For Solar Lanterns to be used in Solar Home System, the lamps used in Lanterns must meet the standards mentioned in clause no. 3.3.1 or 3.3.3. 3.3.5 AC Lamp for ISPS 3.3.5.1 Compulsory: 1. For ISPS with an inverter, lamps must be AC 220V and 50 Hz operated CFL or TL. 2. Lamp must ensure safe and regulated ignition between 220 V ±10% and 50 Hz ±2%. 3. The lamps used, must fulfil criteria 1, 2, 6, 7 & 8 mentioned in clause 3.3.1.1. 3.4 Charge Controller 3.4.1 Compulsory: 1. The charge controller must function in accordance with Pulse Width Modulation (PWM) or On/Off working principles. 2. Deep discharge protection must be included and option for manual de-activation of the deep-discharge protection is not permitted. Low Voltage Disconnection (LVD) for flat plate battery must not be less than 11.8 Volt and for tubular plate battery LVD must not be less than 11.4 Volt and the setting must be within ± 2% of the manufacturer s claim at 25 o C. 3. Low Voltage Reconnection (LVR) must not be less than 12.5 Volt and the setting must be within ± 2% of the manufacturer s claim at 25 o C. 4. Over-charge protection must be included. High Voltage Disconnection (HVD) must be within range of 14 Volt to 14.8 Volt and the setting must be within ± 2% of the manufacturer s claim at 25 o C. 5. High Voltage Reconnection (HVR) must be greater than 13.5V and the setting must be within ± 2% of the manufacturer s claim at 25 o C. 6. Usage of electro-mechanical relay is not permitted. 7. The quiescent current consumption must not exceed 7 ma at nominal system voltage while the non-critical indicators are turned off. 8/13

8. For 12 V systems, voltage drop across the charge controller while charging (PV panel to battery terminals) must not exceed 1 V and while discharging (battery to load terminals) must not exceed 0.5 V. For 24 V systems, voltage drop across charge controller while charging must not exceed 2 V and while discharging must not exceed 1 V. For 48 V systems, voltage drop across charge controller must not exceed 4 V during charging and must not exceed 2 V during discharging. 9. The charge controller must withstand at least 90% of rated current from the PV module to battery and from battery to load at an ambient temperature range of 5 o C to 40 o C. 10. Protection against reverse polarity must be provided in both the PV module and battery sides. 11. Reverse leakage current must be less than 500 micro-amperes (current from battery to dark module) 12. The following minimum information must be included in the label of the charge controller: Brand name, type (On/Off or PWM) and model Solar PV company name Maximum input current in Ampere Maximum load current in Ampere Nominal voltage in volt Size of fuse(s) in Ampere (if applicable) Type of battery to be used 13. The type of charge controller according to battery type (flat plate or tubular plate) must be printed in front cover of the charge controller as part of its specifications. 14. For ISPS, all criteria are valid except criteria No. 2, 3, 4 & 5 where the value of LVD, LVR, HVD and HVR must be multiplied by factor N. Here N stands for the number of batteries in a series connection. 3.4.2 Recommended: 1. The charge controller should not produce radio frequency interference greater than 50mV/m within 2 metres distance. 2. Charge controller boxes should display good workmanship and should provide protection against dust, water, oil, and smoke. 3. For sealed batteries, High Voltage Disconnection (HVD) set point should not exceed 14 Volt. 4. The charge controller should have protection against the effect of temperature and humidity variation. In high mountain areas, it is recommended to use charge controller having following properties to minimize the effect a. Sealed type b. Epoxy encapsulation in PCB 9/13

c. Large surface area PCB board with sufficient gap between electronic components. 5. The smaller systems (less than 5 Wp) using other types of batteries should omit the charge controllers from the system. 3.5 Support Structure for PV Modules 3.5.1 Compulsory: 1. Support frame structures must be made of stainless steel, aluminium, galvanised iron or electroplated iron and must be able to withstand wind speeds of min. 85 km/h so as to be able to resist at least 20 years of outdoor exposure without suffering significant damage or corrosion. 2. Mounting pole must be made of stainless steel, aluminium, galvanised iron, electroplated iron or wood and must be able to withstand wind speeds of min. 85 km/h so as to be able to resist at least 20 years of outdoor exposure without suffering significant damage or corrosion. 3.6 Cables 3.6.1 Compulsory: 1. The cables used must be certified according to the standard "NS344-2052 for PVC insulated copper conductor cables for fixed wiring. 2. Cable sections, which are used out door, especially between the PV module and charge controller must be waterproof and UV resistant. 3. Cables must be colour coded in accordance with the existing electric coding norms. 3.7 Switches, Sockets And Protections 3.7.1 Compulsory: 1. Switches must be certified according to the standard NS or "IS 3854 Switches for Domestic and Similar Purpose. 2. DC sockets must be used with a reverse polarity protection. 3.8 Inverter 3.8.1 Compulsory: 1. The Inverter must have a rated AC output voltage of 220V ± 10% at battery operating voltage from DC 90% to 120% and load current from 10% to 110% of the rated value. 2. The quiescent current drawn by the inverter must not exceed 3% of the rated input current of the inverter. 3. Inverter or Inverter circuits must include: 10/13

Low battery shut down must be at battery voltage not less than 11.8 V for flat plate battery and not less than 11.4 V for tubular plate battery in case of 12 V systems. For 24 V or 48 V systems, low battery shut down voltage must be multiplied by factor N. Here N stands for the number of batteries in a series connection. Short-circuit protection of input and output terminals Reverse polarity protection on DC input terminals 4. Complete documentation for the inverter including the following must be provided: Installation instructions Operating instructions Technical specification and ratings Safety warnings Troubleshooting instructions Information pertaining to the serviceable parts Warranty 5. The minimum information must be included in the label of the inverter: Manufacturers name and model Solar PV company name Rated power in Watt or VA Input and output voltage in Volt Battery connection points & polarity and AC outlet points 6. The inverter input and output terminals must not be exposed to contact by the user. 7. Output frequency must be 50Hz ± 2%. 8. For sine wave inverters, the output waveform s Total Harmonic Distortion (THD) must be less than 5%. 9. Inverter efficiency when operating resistive loads at power levels within 10% to 90% of rated load must be greater than 80%. 10. Inverter must be capable of Operating continuously for at least 4 hours at its rated power under ambient temperature up to 40 C Operating safely for at least one minute at 125% of rated power; Operating safely for at least two seconds at 200% of rated power. 3.8.2 Recommended: 1. The inverter should automatically switch to sleep mode where there is no consumption for 5 minutes. 11/13

2. The audible noise produced by the inverter should not be more than 65 db at a distance of 3 metres from the inverter. 3. Inverter or Inverter circuits should include: Low battery alarm Over temperature Protection Protection against lightning induced transients. 4. There should be no radio interference greater than 50 mv/m at a distance of 3 metres under all operating conditions. 3.9 Solar Pump for PVPS 3.9.1 Compulsory 1. The wire to water efficiency of motor- pump unit must be at least 30%. 2. The following minimum information must be included in the catalogue of the pump: Manufacturer name and model Nominal voltage in Volt Wire to water efficiency Maximum head in metre Maximum flow rate 3. The motor-pump set must include protection against Dry run Sand and silt Reverse polarity (for DC motor-pump set) 3.10 Solar Vaccine Refrigerator for ISPS 3.10.1 Compulsory: 1. The solar vaccine Refrigerator must be certified in accordance to WHO standards. 3.11 Grounding for ISPS and PVPS 3.11.1 Compulsory: 1. All metallic enclosures and structures of the system must be bonded and grounded using the shortest practical route to an adequate earth contact using an uninterrupted conductor of at least 16 mm 2 cross-section. 12/13

2. The earth resistance must not exceed 10 Ohms with the bonding resistance 2 not exceeding 0.2 Ohms. 3.12 Other Loads for ISPS 3.12.1 Recommended: 1. The loads connected to ISPS should be energy efficient as far as possible. 4 QUALITY TESTING The Solar Energy Test Station (SETS) or any other national test lab or a reputed third party testing lab accredited by the appropriate authority and accepted by AEPC, should carry out the quality test of the components according to the above mentioned and referred technical standards. Approved on October 2005 by (Signed) (Dr. Madan Bahadur Basnyat) Executive Director, AEPC Office Seals 2 Between the metal parts of the devices and metal parts of the consumer earth terminal. 13/13