Safety+Class+II_06_2006

Safety Class II testing of PV Modules Dipl.-Ing. Herbert Becker TÜV Rheinland Immissionsschutz und Energiesysteme GmbH 51105 Köln June 2005 2 Introduction Recent marked growth in the use of photovoltaic (PV) modules, also in façades, has made suitable protection from electric shocks an increasingly important feature. This applies not only to personnel involved in installation and operation of the PV system but also in a wider context, because PV elements are usually generally accessible and can be touched by anyone. Protective insulation according to IEC 60664 part 410 (together with other possibiliTR IEs) offers particularly suitable protection for persons in the DC circuit of PV systems. Protection is provided here by using operating materials with equivalent insulation, i.e. operating mate- rials in protection class II. Protection from electric shocks in these operating materials is cre- ated solely by special insulation (doubled or reinforced version) of the live parts. The insula- tion capability of the operating material must be sustained throughout its service life. The protection objective for performing tests on PV modules was formulated from this gen- eral description, and corresponding tests were defined on this basis. Protection objective on carrying out tests The general protection objective on carrying out tests on PV modules is to provide evidence that the special insulation capability is sustained throughout the entire service life of the module when used for its normal purpose. Normal purpose means, for example, that the modules are exposed to weather conditions (UV radiation, temperature, humidity, hail, snow, wind pressure) which may not cause ageing or a reduction in the insulation properTR IEs of the modules. In addition, the insulation of the modules may not be impaired by common mechanical loads (jolts, scratches) during transport, installation and operation. The insulation must be designed in such a way that overvoltage caused by lightning does not have a detrimental effect on the insulation capability. 3 The high system voltages occurring within a generator circuit may not cause premature age- ing or deterioration of the insulation properTR IEs, particularly in the case of thin insulating layers. Test procedure when testing photovoltaic modules for their suitabil- ity as protection class II equipment Principles The test procedure for suitability as class II equipment has been elaborated on the basis of EN 50178 (1998-04) “Electronic equipment for use in power installations“. This standard stipulates minimum requirements for the production and installation of such operating mate- rials in electrical systems. Measures/test procedures have been elaborated to describe suitability as protection class II equipment in combination with IEC 61140 (2001-10) “Protection against electric shock – Common aspects for installation and equipment“, which serves as directive for the classifica- tion of electrical and electronic equipment as regards protection from electric shocks in the case of failure of the insulation, and based on the following standards. The following national and international regulations shall be used as a basis for the proof of the PV modules as Safety Class II Equipment: IEC 60664-1 (2003-11) Insulation coordination for equipment within low-voltage systems - Part 1: Principles, requirements and tests. IEC 61140 (2001-10) Protection against electric shock – Common aspects for installation and equipment. EN 50178 (1998-04) Electronic equipment for use in power installations IEC 61721 (1995-03) Susceptibility of a photovoltaic (PV) module to accidental impact damage (resistance to impact test) 4 Tests The modules are expected to comply with the specifications of IEC 61215 / IEC 61646 in order to ascertain general suitability as regards environmental impact. Marking Protection class II equipment must be marked with a symbol as per IEC 60417, symbol 5172 ( ). Extension of a basic certificate when changing the module design Basic protection class II certification refers to the specific design of a module. If the certified module type or individual components are changed (e.g. new junction box, new cells), it is possible for the basic certificate to be extended on the basis of visual and drawing tests, to- gether with any necessary qualification tests for the new module design, without having to repeat the entire test procedure. Prerequisite for an extension is always qualification to IEC 61215 / IEC 61646, depending on the module type. Summary Protection insulation is an ideal means of providing DC circuits with protection for persons. The protection is achieved by using protection class II equipment. The described test proce- dure can be used to demonstrate the suitability of PV modules as operating materials in pro- tection class II. Minimum requirements/general conditions can be stipulated so that the granted basic certifi- cate can also be extended to “structurally identical“ modules. The basic certificate can also be extended to modules in which one or several components have been changed on the basis of visual and drawing tests and, where applicable, neces- sary qualification tests. 5 Safety Class II Qualification Tests on PV Modules Test Test Condition 1.1 Visual inspection Damage, alteration of material 1.2 Drawing inspection Checking of the technical documentation, conformance dec- larations, verifications, etc. 2.1 Test of clearance and creepage distances Minimum distances in accordance with IEC 60664-1, de- pending on the rated voltage, pollution severity and the safety class 2.2 Proof of IP protection Verification / test in accordance with IEC 60529 (minimum IP 54) 2.3 Impulse load test Test of the impulse load capacity on module junction box and cable glands with steel ball 2.4 Cut test Verification of the mechanical stability on foils. Test in accordance with UL 1703. The voltage depends on the rated voltage. 2.5 Test of the suitability of stan- dard components Mechanical stability, UV resistance, denseness, dielectric strength, etc. of standard components like, junction boxes, terminals, diodes, cable glands, cables, connectors, etc. 3.1 Impulse voltage test Impulse voltage test with low energy Determination of the module capacity Measurement of the insulation resistant Impulse voltage test with 6 kVp Check of capacity and insulation 3.2 High voltage test Test voltage: 4 x U n + 2000 V Increase of the test voltage up to the rated level within 30 seconds, hold for 1 minute. 4.1 Measurement of partial- discharges Test program in accordance with IEC 60664-1 1 1 complete Module 1 module without frame 2 junction boxes pieces of reverse side foil 1.1 Visual inspection 1.2 Drawing inspection 1 Complete module 1 Laminate 10 Pieces of reverse side foil 2.1 Test of clearance and creepage distance 3.1 Impulse voltage test at 6 kV 4.1 Measurement of partial-dischar- ges (at reverse side foil-modules, manufactures verification or ex- amination) 2.2 Proof of IP-protection (manu- facturer’s proof or test) 3.2 High-voltage testing at 4 x U n max + 2000 V 2.3 Impulse load − spring-operated impact-test − steel ball test Aim of protection: The insulation capability of the solar modules has to remain the same during the whole life time at normal application (transport, installation, operation) Prerequisite: IEC 61215 (2005-04) or equal EN 61215 (1996-10), IEC61646 2.4 Scratch test (Cut-Test, UL 1703, 05/93) Testing fundamentals: EN 50178 (1998-04) IEC 61140 (2001-10) (DIN VDE 0106-1 (1982-05) and DIN VDE 0106-101 (1986-11) 2.5 Test of the suitability of standard components IEC 60664-1 (2003-11) (DIN VDE 0110-1 (1997-04) IEC 61721 (1995-03) Safety Class II - Examination of PV Modules 2 Repetition of Qualification Tests for the Extension of the Safety Class II Certificates Test Modification 1.1 Visual Inspection 1.2 Drawing Inspection 2.1 Clearance Creepage Distances 2.2 IP Pro- tection 2.3 Impulse Load 2.4 Scratch Test 2.5 Standard- Components 3.1 Impuls Voltage 3.2 High Voltage 4.1 Partial Discharge A Cell type, cell configuration B Foil type Reverse (front-) side C Glass type- Front oder reverse side D Junction box, terminals, cable terminal E Frame Removal or alteration F Increase / Decrease in the module area, no. of cells necessary dependent on the results of Safety Class II - Examination of PV Modules