NEPQA AND SOLAR TESTING IN RETS By Sujita ThakaliMSR/071/516

CONTENTS

Introduction Block DiagramDescription of ComponentsTesting of solar panelPhotoConclusion

INTRODUCTIONNEPQA is the Nepal Photovoltaic Quality Assurance which is the technical standard for the components of a Solar Photovoltaic(PV) system.The standard doesn’t remain constant it changes. Based on this documents the RETS will test and certify the quality of the PV systems and components in PV applications.The RETS is authorized to carry out the quality test of the solar photovoltaic system and its components and issue the certificate using the Sampling Plan and Test Procedures of RETS.

BLOCK DIAGRAM

Charge Controller

Battery

Solar panel

AC appliances

Mobile USB Connection

Sun

Load Center

Inverter

DC lamps

Flow of current

DESCRIPTION OF COMPONENTSSolar PanelCharge ControllerBatteryInverterDC LED Lamp

SOLAR PANEL

1. Different Capacity of Solar Panel are available which consists of Diode for preventing from the reverse flow of electricity from the Battery during night.

2. According to the Nepal Photovoltaic Quality Assurance(NEPQA) solar panel should be of at least 17 volts at maximum power designed for the 12 volt system voltage so that solar panel can charged the Battery system.

3. Generally for the design of the small solar home pv system it consists of 36 cells. Each cell has the voltage of 0.6 volt what ever dimension it has been cut and power of the panel can be increased by increasing the area.

BATTERY • There are different types of Battery available in the market some are compliance and some are not.•The capacity of the battery is determined by the Ampere hour rather than its voltage and label with C10, C20, C30, etc.•The operation life cycle of the Li-Ion/Ni-MH battery must be at least 3000 cycles at 20% DOD and 15000 cycles at 80% DOD. •According to the NEPQA, for the battery with capacities greater than 10Ah, deviation of battery capacity from its rated value must not exceed -5% to 20% within 10 cycles of the test. And for the battery with the capacity less or equal to 10Ah, the deviation of battery capacity from its rated value stated by the manufacture must not exceed the limit of -5% to +20% within 5 cycles of test. This clause applies for all type of batteries.

CHARGE CONTROLLER1.The function of Charge Controller is to prevent from the deep discharge with any options for manual deactivation that is adaptable to the battery type used, applicable to advanced type like microcontroller based Charge controller and also prevent from over charging of battery.

2.Low Voltage Disconnection(LVD) and Low Voltage Reconnection(LVR)

3.Both have the setting point within ±2% at 25°C

4.i.e. for the battery of 12V LVD should be not less than 11.4V and LVR should be not less than 12.5V

3. High Voltage Disconnection(HVD) and High Voltage Reconnection(HVR)

4. High Voltage Disconnection must be within the range of (14-15)V for the 12V system and its also depends on the type of battery used.

CC CONTINUE…..

7. The charge controller must withstand the rated current from the PV module to battery and from battery to load at an ambient temperature range of -5ºC to 40ºC.8. There are mainly three terminals in Charge Controller. One terminal is for Panel Connection, one for the battery connection and another one is for Load connection.9. For the Small Home Solar PV design the charge controller that has USB port and lightening terminal are the main parts of the charge controller.10. The charge controller must function in accordance with the pulse width modulation or the maximum power point tracking principles

INVERTER

The inverter must have the rated AC output voltage of 220V ±5% at the battery operating voltage from DC 90% to 120% and maximum load current from 10% to 110% of the rated value. Output frequency of the inverter is 50hz ±2%.Inverter Efficiency when operating with resistive loads at full load must be at least 85%.The quiescent current drawn by the inverter must not exceed 2% of the rated current of the inverter.The inverter shouldn’t produce the noise more than 60db at 2m.

INVERTER CIRCUIT PROTECTIONLow battery shut down must be at battery voltage not less than 10.5 V for tubular plate battery in case of 12 V system. For 24 V or 48 V systems low battery shut down voltage must be 10.5N where N is the no of Batteries in series connection.Short circuit protection of the output terminals.Reverse polarity protection on DC input terminals.Appropriate indicators main charging , inverter ON, short circuit and overloadThe inverter should be have cooling systemor appropriate heat sink

Inverter must be capable of operating safely for at least one minute at 125% of rated power and at least 5 seconds at 150% of rated power.The minimum information must be included in the label of inverter are

a. Manufacturer’s name and model b. Rated Power in Watt or VA C. Input and Output voltage in Volt and Frequency in Hz d. Charging current, Load current, power factor, efficiency e. Inverter Type

SOLAR PUMPThe pump can be centrifugal, positive displacement, progressive cavity, submersible or surface type meeting the safety standards of EN 809 and complies with IEC 60034-1Pump motor efficiency must be at least 60%.The pump must have thermal protection against overload, reverse polarity and temperatureThe pump must use standard submersible cable for submersible pump.The pump or pump set must have provision of stopping operation under dry running or insufficient energy supply.

The pump must have protection against sand and silt.Indelible label must be fixed on the pump, containing the details 1. Name of the manufacturers or distinctive logo 2. Model name and serial number The motor and pump must be warranted for at least 2 years.The pump must be manufactured with non corrosive materials. Ceramic or equivalent non corrodible materials must be used for bearings. Rotors and impellers must be made of stainless steel with minimum grade of AISI 304 or higher.Oil must not be used for lubrication.

LAMP

• DC Led Lamp are prefer in the PV System. The viewing angle of individual WLED must be equal to or greater than 100 degree.•The luminous efficiency of individual WLED must be at least 100 Lumen/Watt.•The lamp driver circuit efficiency must be at least 80%•The Color Rendering Index (CRI) of the individual WLED must not be less than 60 and the color temperature must be in the range of 5000K and 6000K•In the lamp of multiple WLEDs, the WLEDs used must not differ by more than 10% in individual WLED parameters (forward voltage and color temperature) at specified current.•The rated power of Lamp must be at least 1 watt and acceptable tolerance for all to be +/-10%.

TESTING OF SOLAR PANEL

Even though there are 17+ Tests in CEC JRC ESTI Specification 503In RETS there are two types of Tests in RETS 1.PIT(Product Introduction Test) 2. Random Sampling Test(RST)PIT is done by observing the PV module and gathering the indelible informations label where as RST in done by taking a large number of sample from the population and proceed on testing.It consists of the log book where the required information can be logged in.

LOG BOOK

After filling the information in the log book then it is proceed further in Laboratory called Quick Sun Solar Simulator Setup which consist of three rooms where one room consists of source of light- Xenon Lamp, flash generator where as in second room there are temperature sensor, Monitor cell, Electronic unit and another room where there is operator who control the system through software

It is a setup in a dark room where each part of the wall is black painted so that there is no any reflection.Temperature Sensor is connected with the electronic unit to sense the temperature of the simulation setup.Monitor Cell is a unit cell which acts as a reference cell that compares the irradiance and the uniformity with the test PV module and calibration takes place simultaneously as the light flash from the Xenon Lamp.Electronic Unit acts as bridge between the PV module, Monitor Cell, Temperature sensor, Flash Generator and PC. It is main part of this setup because it controls the every components.

PROCEDUREInitially the panel is given a code and is hanged at the wall of the Simulator setup.Then after connecting the probe from electronic unit to the panel the room is closed. The operator open the software and from the log book the informations are filled by clicking on the Product database and then since all the setup is ready then Measure button is clicked on.When the Measure button is clicked the flash is stroke at the panel from the Lamp. Then the software automatically provide the output whether it is pass or fail.

PHOTOS

CONCLUSION In this way according to the NEPQA standard of Panel, charge controller, battery inverter and lamps are known and have overview on Solar Panel Testing.

REFERENCES

www.retsnepal.org.np Credited to www.ioe.edu.np(CES- Department) Dr. Er. Ajay Kumar Jha(I.O.E pulchowk) Er. Rabindra Lamichane (RETS) Er. Madan Oli (RETS) Er. Rudra Mani Pokharel(Ex. Technical Manager)

Thank you(any querries are

welcome)