REPORT ON THE PID EFFECT ON PHOTOVOLTAIC MODULE: LOCATED IN : POGLIANO MILANESE (MI) VIA MATTEI 3, TÜV Rheinland Italia S.r.l.

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2 Page 2/19 REPORT ON THE PID EFFECT ON PHOTOVOLTAIC MODULE: LOCATED IN : POGLIANO MILANESE (MI) VIA MATTEI 3, TÜV Rheinland Italia S.r.l. REQUESTED BY: OMRON PART 1: CASE OF STUDY OF THE INFLUENCE OF INVERTER TECHNOLOGY IN PID (POTENTIAL INDUCED DEGRADATION EFFECT) GENERATION

3 Page 3/19 CONTENTS CONTENTS 3 AIM 4 LOCATION OF THE PLANT UNDER INVESTIGATION 4 SCOPE 4 APPLICABLE STANDARDS 4 EQUIPMENT USED 5 INITIAL CONSIDERATIONS 6 MEASUREMENT RESULTS 16 STC ANALYSIS 18

4 Page 4/19 AIM The aim of this report is to verify growing of PID on PV module, using different transformerless inverter technology. This is at the request of OMRON, hereinafter referred to as the 'client', acting on behalf of TÜV Rheinland Italia SRL, hereinafter referred to as TÜV Rheinland. LOCATION OF THE PLANT UNDER INVESTIGATION The test is executed in our laboratory in TÜV Rheinland (Pogliano Milanese) SCOPE The scope of this procedure is to verify PID growing. The test is structured as follows: A proof with a transformerless inverter with standard technology. A proof with a transformerless inverter with Omron technology (model: KP100L-OD-EU). APPLICABLE STANDARDS Quality control shall be performed in accordance with the operating and technical procedures of TÜV Rheinland. The whole test is conduced following: - TÜV Rheinland Italia S.r.l. internal standards and procedures - EN : Environmental testing - Part 2-78: Tests - Test Cab: Damp heat, steady state - IEC : Photovoltaic devices Part 1: Measurement of photovoltaic current-voltage characteristics

5 Page 5/19 USED EQUIPMENT The following equipment was used to perform the various measurements: Manufacturer Model Type Equipment number YOKOGAWA WT500 Power Analyzer AGILENT 34970A Data Logger REGATRON TopCon Quadro Programmable DC Power Supply VOTSCH VCV /S Climatic Chamber PVE PVPM 1000C Irradiance Analyzer PVE SOZ-03 Solar Cell Tab.1

6 Page 6/19 INITIAL CONSIDERATIONS 1._CAUSES OF POTENTIAL INDUCED DEGRADATION (PID) The PID effect occurs for three principal causes: - Bias voltage applied - Temperature - Humidity (surface conductivity) 2. UNCERTAINTY RESULTING FROM THE MEASUREMENT METHOD AND THE MEASURING DEVICE ITSELF The uncertainty on electrical and physical measures is: Voltage: better than 1% Current: better than 1% Irradiance: better than 5% (0-1300W/m2 at 1.5AM -air mass-) Temperature: better than 3,5% on determination of Junction's temperature; C The measures refer only the status of modules at the measures' time. The whole data used during the test are stored by devices showed in Tab.1, every elaboration is done starting from those. In the end of this report shall be mentioned the way used to elaborate data. 3. DESCRIPTION OF THE WORK Test is divided into three different parts, in the following is exposed the structure of the procedure. First of all the climatic chamber is prepared at critical conditions: - T=60 C - HR=85% The module is introduced inside the chamber with its surface immersed in water, to increase surface conductivity, then the module is irradiated by a solar lamp positioned under the chamber to record the I-V curve at the beginning of test and to measure the irradiation of the lamp. After this operation the lamp is switched-off and the bottom of chamber is closed with a wood. Then, module is connected and supplied with 590 V DC voltage. At this point setup is ready and test starts.

7 Page 7/19 4. SETUP PICTURES In this session there are pics of the setup described above: Testing set-up

8 Page 8/19 Testing set-up Earthing of the PV module (E.U.T)

9 Page 9/19 I-V curve measurement

10 Page 10/19 I-V curve measurement Fig.1

11 Page 11/19 4. DESCRIPTION OF THE MODULES UNDER TEST The type of module used has the following characteristics, according to manufacturer datasheet and client requirement: Tab.2

12 Page 12/19 5. DESCRIPTION OF THE EQUIPMENT UNDER TEST To perform the test are used different panels for every step, all the modules have the same characteristics shown in the previous paragraph. In the follow there is a list of used panels with specification of which configuration they were used in: Module under test: /5_ (S/N: ) standard technology inverter test Module under test: /1_ (S/N: ) Omron inverter test (KP100L-OD-EU) The other equipment under test is the Omron inverter, in the follow a table contains pictures of this one and of labels pasted on it.

13 Page 13/19 Marking plate Fig.2

14 Page 14/19 6. SETUP SCHEME Measurements circuit: Fig.3 1 The figure above represents the scheme of the setup circuit, in the follow there is a description of every parts of this circuit and all the contacts. Starting from left there is the DC generator (REGATRON) whose negative pole is connected with positive pole of EUT. Negative pole of DC generator is linked with inverter passing through the EUT that is connected serially with a short circuit; EUT and inverter are both grounded (PE cable in figure). To close the circuit, positive poles of the inverter and the DC generator are connected and serially at this connection there is a shunt to control voltage on this line (shunt gives back a current value that has to be transformed as voltage). Shunt is one of the system used to monitor values during the test, but there are other two devices, in figure are indicated with a circle. V(-;PE) controls voltage between REGATRON s negative pole and earth. At the end of every proof two operation are made. First one is to store data in conditions of short-circuit and open-circuit, these measurements are done to create the I-V curve of the panel (topic of next paragraph). Second operation is to analyse lamp s irradiation to ensure that there is no performance decay (this operation is done before and after the proof; values are reported in next session. See Fig.6). To guarantee the repeatability of the irradiation measurement is important to replace the module in the same position to have the same light incidence. 1 E.U.T (PV module) inside climatic chamber.

15 Page 15/19 In the figure it s possible to see solar cell positioning used to verify the irradiation value before I-V curve measurement (not at STC conditions): 18, ,5 9,5 Unit of measure used in Fig.4 is centimeters [cm]. Fig.4

16 Page 16/19 MEASUREMENT RESULTS 1. MONITORING To monitor the development of the test a set of data is stored during the day and one during the night. This procedure permits to keep controlled the project, in the following table are reported average data for every storage done. 1 st measurement: Days Voltage ( - ; PE) [V] , , , , , , , , , , , ,15 Tab.3 In table above it s possible to see voltege s trend between negative pole of DC generator and ground connection of the module. These values are reported because of their importance to understand how the other brand inverter works, or rather positioning earth connoection in the middle of the poles distributing the load in two symmetric halfs, more or less.

17 Page 17/19 2 nd measurement: Days Voltage ( - ; PE) [mv] , , , , , , , , , , , ,48 Tab.4

18 Page 18/19 STC ANALYSIS 1. SUMMARY OF STC MEASUREMENT PERFORMED The following table reports values of modules that could be affected by PID effect, monitoring these values permit to understand PID manifestation. Isc[A] Voc[V] FF[%] Configuration S/N Before conditioning After conditioning Before conditioning After conditioning Before conditioning After conditioning KP100L-OD-EU ,684 8,834 2,481 2,452 64,1 64 Other inverter ,697 6,766 2,464 1,135 64,3 27,5 Pmax[W] Configuration S/N Before conditioning After conditioning Testing time [h] MaxPloss % KP100L-OD-EU ,817 13, ,28% Other inverter ,778 2, ,69% Tab.5

19 Page 19/19 In the follow there are reported graphs before and after the test for both panels: PANEL S/N (other brand transformerless inverter) STC MEASUREMENT (Before conditioning) STC MEASUREMENT (After conditioning [360 h] Fig.10

20 Page 20/19 PANEL S/N (Omron inverter KP100L-OD-EU) STC MEASUREMENT (Before conditioning) STC MEASUREMENT (After conditioning) [360 h] Fig End Test Report