Standards for the Load

This overview on standards for loads is an extract of the publication: GTZ, Division 44, Environmental Management, Water, Energy, Transport: Quality Standards for Solar Home Systems and Rural Health Power Supply. Photovoltaic Systems in Developing Countries, February 2000.

Comment: In the meantime, radios, TV sets, etc. are directly acquired by the users in the conventional appliances market; the associated energy consumption tends to be modest and they are highly standardised products. For these reasons, only light fixtures are reviewed in these specifications, while features of radios and TV sets are entrusted to training and general information activities.

Lighting Fixtures with Fluorescent Lamps and Ballasts

Comment: The standardisation of lighting fixtures with energy-saving fluorescent lamps and electronic DC ballasts is quite well described in IEC 60924 and 60925 “DC supplied electronic ballasts for tubular fluorescent lamps - General and safety requirements and - Performance requirements”. As these kinds of lights are utilised in public transport vehicles, aircraft and emergency lights, as well as in consumer applications like caravans and private cars, there is a much wider market for these products than just for PV solar systems. But there is still a need for standardisation of the special features; such lights must be compatible with PV applications, especially for the operation in Solar Home Systems in developing countries. Therefore, a new standard-proposal was drafted by the CENELEC CLC/BTTF 86-2 committee for "Photovoltaic Lighting Systems, Part 1, 2 and 3", which was also accepted by the IEC TC 82 and is currently circulating among the committee members for discussion and correction. A copy of the current draft version (as of 07/98) was kindly made available by TÜV-Rheinland, a member of the standards committee. The final version of this standard will probably be released by the end of 2000 and will not differ much from this draft. The draft will be the basis for the following specifications:

Scope of the Standard:

The scope of this standard comprises electronic ballasts and fluorescent lamps for use in photovoltaic systems. The electronic ballast and the lamp should be a matching pair, as recommended by the manufacturer or the supplier. If there is no recommendation available, the operation of the fluorescent lamp should at least be in line with the appropriate data sheet of IEC 60081 or IEC 60901.

Definitions:

Lighting systems in PV stand-alone systems serve to illuminate dwellings and working areas. They are DC-supplied and thus consist of an electronic ballast, a fluorescent lamp and some kind of fixtures. The rated voltage range (V_R), at which the ballast may be operated and at which the proper and correct start, and operation, respectively, of the fluorescent lamp is safeguarded (IEC 60924) will be 10 V < V_R < 16 V for a 12 V system and 20 V < V_R < 32 V for a 24 V system.

The following technical data have to be submitted by the manufacturer and will be verified during the tests:

• Casing of electronic ballast: material, IP-protection, type of assembly
• Type of lamp, certified according to IEC 60081 (tubular lamps) or IEC 60901 (single capped lamps)
• Terminals (marking, type, for which cable)
• Fuses (type, where is what protected by the fuse)
• Rated voltage range at which the ballast safely starts and operates (10 to 16 V for 12 V system, 20 to 32 V for 24 V system), see IEC 60924
• Design voltage according to IEC 60924 (about 85% of maximum rated voltage)
• Product identification and labels according to IEC 60924 and 60925

Documentation must include:

• Technical data
• Operating instructions
• Installation instructions
• Personal safety instructions
• Environmentally safe recycling and disposal instructions
• Warranty conditions
• Accessories

The visual inspection will evaluate the quality performance of the light fixture, the electronic ballast and the accessories.

Electrical parameters and performance tests:

• Starting performance test according to IEC 60925, paragraph 5 at ambient temperature of 20 to 25°C, start within 5 seconds, 1 firing failure permitted.
• Preheating condition test (if preheating is applied) according to IEC60925, section 7, electrode voltage range: 6.5 V < V_el < 11 V for high-resistance electrodes, 3.05 V < V_el < 6.5 V for low-resistance electrodes. Preheating is recommended, but is not imperative.
• Open circuit voltage at lamp terminals as of IEC 60925, section 6.
• Lamp current shall not be 25% higher than in operation with the reference ballast in

the voltage range 8.5 V < V_bau < 13.6 V for a 12 V system (17 V < V_bau < 27.2 V for a 24 V system).

• Input current of the electronic ballast during operation with reference lamps shall only deviate from the data given by the manufacturer by less than 15%. No alternating effective current components may exceed 10% of the direct current.
• Maximum electrode current given in IEC 60081 or IEC 60901 data sheets may not be exceeded.
• Waveform of the lamp operating current shall not exceed the tolerance limits given in IEC 60925, crest factor of the lamp current may not exceed 3, direct current components may not exceed 2% of the RMS value.
• Stability of operation: uninterrupted, flicker-free and stable operation within the rated voltage range.
• Power consumption of the lamp should range between 90 to 110% of the nominal power consumption of the lamp within the rated voltage range.
• Efficiency test is still under consideration.
• Switching durability of the ballast/lamp combination shall be a minimum of 10,000 operating cycles with 60 s ON and 120 s OFF time.

Mechanical parameters and environmental conditions:

• Mechanical stability of all components shall be tested by vibrations test (acc. IEC 60068-2-6, stringency, see proposed standard) and
• shock test (acc. to IEC 60068-2-27, stringency, see proposed standard), while specimens are not packed and not live.
• Temperature and humidity resistance shall be defined and tested in accordance with the climatic conditions of the project (application) region (see IEC 60068-1).
• For application in tropical climates, a “cyclical damp heat test” (acc. to IEC 60068-2-30) will be performed with temperatures up to 55°C (specimen not live, resp. 40°C (specimen run with design voltage).
• Corrosion resistance and long-term stability will be evaluated after this damp-heat test.
• Operation at different temperatures will be tested according to IEC 60925, with five cycles between lowest and highest ambient temperature given by the manufacturer and 200 hours at maximum surface temperature (surface temperature may not exceed 80°C).
• Suitability of construction and sturdiness of casing as of IEC 60068-2-63 or IEC 60335-1, section 21 with a 250 g dead stroke hammer from different directions, operational test of changing fuse and lamp without danger of injury.
• IP protection code according to IEC 60529, IP 20 for solidly built indoor applications, otherwise IP 54.

Safety tests according to IEC 60598 and IEC 60924:

• Insulation resistance as of IEC 60598, section 10 and IEC 60924, sections 12 and 13
• Dielectric strength as of IEC 60598, section 10 and IEC 60924, sections 12 and 13
• Voltage impulses at electronic ballast as of IEC 60924, section 18
• Terminals as of IEC 60598, sections 14 and 15
• Safety earth terminal as of IEC 60924, section 9
• Creepage and clearance distances as of IEC 60924, section 10 for electronic ballast and section 11 for lighting system
• Fault conditions at electronic ballast as of IEC 60924, section 14
• Abnormal operating conditions will be tested as of IEC 60924, section 19:

- Removal of lamps - Non-igniting lamps - Reverse polarity of input voltage - Surge voltage of 26 V for 12 V system (52 V for 24 V system) as maximum open circuit voltage from PV generator

• Screws, conductive components and connections as of IEC 60598, section 4
• Heat and fire resistance as of IEC 60695-2-1 (glow wire ) and –2 (needle flame)
• Protection against accidental contact with live parts as of IEC 60598, section 8, and IEC 60924, section 11

Electromagnetic compatibility (EMC) tests:

• Line-conducted interference emission shall be tested at least on the output (load) line in the radio-frequency range from 10 kHz to 30 MHz (acc. to EN 55015).
• Irradiated interference emission at a distance of 3 meters will be tested in accordance with EN 55015, limit values acc. to EN 55015.
• Resistance to interference from fast, low-energy pulses (pulse group) will be tested according to IEC 61000-4-4 (0.5 kV).
• Resistance to interference from single high-energy impulses like atmospheric discharges (lightning) according to IEC 61000-4-5 with 0.5 kV.
• Optional: Resistance to interference due to electromagnetic fields shall be tested in reference to IEC 61000-4-3 (required field strength 3 V/m), only if broadcasting

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