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Efficiency Household Lighting Toolkit
Key Issues
Voltage Fluctuation
Voltage fluctuation refers to the presence of any distortion on the network, including electronic
disturbance to other appliances. Wide voltage fluctuation causes higher temperatures, which
can cause circuits to burn out, leading to significant damage to the circuit as well as the
equipment. Such disturbances have led CFLs in some cases to have shorter lifetimes. Since the
power systems in many developing countries are subject to substantial voltage fluctuations, the
technical specifications define the range of nominal voltages ±10 percent of rated operating
voltage for the performance of the CFL without a reduction in the rated life. Higher voltage
tolerance may imply higher costs, although the cost differential has been very small or zero, as
observed in recent procurements. Better-quality CFLs with higher-rated lifetimes are also able to
tolerate higher voltage fluctuations.
The primary cause of voltage fluctuations in the medium-and high-voltage grid (>1000 VAC) is
the time variability of the reactive power component of fluctuating loads. In the low voltage grid
(for example, 230/400VAC) it is the fluctuating load of active and reactive power. Also variations
in the distributed energy resources) generation capacity can have an effect and, because the
number of such installations will increase in the future, it can be expected that voltage
fluctuations will increase accordingly. For lamps, the flicker that is generated significantly
impairs vision and could cause general discomfort and fatigue. The permissible magnitude of
light flicker is regulated by International Standards related to incandescent lamps (ILs), or socalled general lighting service (GLS) lamps. For these ILs the permissible supply voltage
variation (+/-10 percent) causes an incandescent lamp to deliver as little as 70 percent or as
much as 140 percent of its nominal luminous flux. The same is true for other filament lamps that
are directly operated by the mains (for example, mains voltage halogen lamps). Fluorescent
lamps are less sensitive and will vary only +/-20 percent, and even less when they are operated
by inverters with power factor controllers, for example, all electronic ballasts above 25 W.
Voltage fluctuations cycle much faster in CFLs than in old tube fluorescents, so there is no
perceptible flicker. In practical tests, lamp performances have been generally better in areas
where the power quality is fairly stable. Voltage fluctuation could imply that the network supply is
not stable, that is, that it is below 230 V or above 260 V. Most lamps that have been tested at
the voltage variation of 6-10 percent have passed the test, thus functioning well within this
tolerance level.
Energy Efficiency Household Lighting Toolkit