Use the following procedure to identify hot spot sensitive cells:a) Expose the unshadowed module to the radiant source with irradiance between 800 W/m 2and 1 1 00 W/m 2 using one of the following:? A pulsed solar simulator where the module temperature will be close to roomtemperature (25 ± 5) °C.? A steady-state solar simulator where the module temperature shall be stabilised within±5 °C before beginning the measurements.? Sunlight where the module temperature shall be stabilised within ±5 °C before beginningthe measurements.For bifacial modules, exposure for cell selection is to the module front, with the module backside covered to sufficiently limit the contribution from the non-exposed side of the moduleto or below the levels specified for "non-irradiated background" in IEC TS 60904-1 -2.b) Shadow each cell completely in turn, measure the resultant I-V curve and prepare a set ofcurves like Figure 4. For bifacial modules, if double-side illumination is utilized, both thefront and the back of the cell shall be shadowed entirely. If single-side illumination is utilized,the rear shadowing is accomplished by the requirement of non-irradiated backgrounddefined in IEC TS 60904-1 -2.NOTE For the SP case the deformation of the module I-V curve is added to the sectional I-V curve of the fullyilluminated parallel sub-section and so does not continue to V oc .c) Select the cell adjacent to the edge of the module that has the lowest shunt resistance, i.e.the one with the highest leakage current.d) Select the two lowest shunt resistance cells (in addition to the cell in c), those with thehighest leakage current.e) Select the cell with the highest shunt resistance.f) For bifacial modules, if some cells are permanently shadowed by design (e.g. junction boxor back rails), those cells shall also be selected for hot-spot testing.g) Begin cell testing procedure by determining the worst case shadowing condition for each ofthe selected cells:1 ) Expose the unshadowed module to a single-sided irradiance in the range of 800 W/m 2to 1 1 00 W/m 2 . The exposure shall meet the requirements described in 4.9.5.2 a).2) After thermal stabilisation of ±5 °C is attained, measure the module I-V characteristicand determine the maximum power current I MP1 (initial performance P MP1 ).3) Expose the module to irradiance meeting the requirements of 4.9.5.2 a). Then use oneof the methods in step 4) below to determine the worst case shadowing for each selectedcell.4) Determine the worst-case shadowing for each of the selected test cells use one of themethods i) to iii) below.i) If the cell circuit is accessible, short-circuit the module and attach the currentmeasuring equipment such that it is reading only the current through the cell stringunder test. For each selected test cell, shadow that cells and determine what shadowlevel results in the current through the shadowed cell being equal to the unshadowedI MP1 determined in step g)2). This is the worst case shadowing for that cell.ii) If the cell circuit is not accessible, the first option for determining worst caseshadowing involves taking I-V curves. Take a set of I-V curves with each of theselected test cells shadowed at different levels as shown in Figure 5. Determine theworst case shadowing condition, which occurs when the current through theshadowed cell (the point where the by-pass diode turns on) coincides with theoriginal unshadowed I MP1 determined in a), like curve c) in Figure 5, at the sameirradiance level as used in a). If the bypass diode does not turn on when the selectedcell is fully shadowed, the worst case hot-spot condition is achieved by completelyshadowing the cell.