LEDs use a fraction of the power (80% - 90%) required by conventional filament bulbs. Solid-state design allows LEDs to withstand shock, vibration, frequent switching (electrical on and off shock) and environmental (mechanical shocks) extremes without compromising their famous long life—typically 100,000 hours or more.
Incandescent lights heat a metal filament that radiates light inside a glass bulb. They radiate white light, which consists of a wide spectrum of electromagnetic radiation. Incandescents generate high-intensity light for a short operating lifetime and are susceptible to damage from shock, vibration and temperature extremes.
(see Figure C)
An Example: In 1995, New York State Electric & Gas Corporation (NYSEG) entered into a joint testing of LED bulbs. The basic agreement called for NYSEG to test the LED lamps in a specific substation and give a report shortly after installation and again at the end of the test period. LEDtronics, Inc. supplied the bulbs and they were installed in February 1996. The station uses over 100 bulbs.
Each incandescent bulb in the station was turned on and off then back on once before removal. Twenty percent of the incandescent bulbs failed. The same process was used with the LED lamps. None failed.
As of December 1997 (22 months later), NYSEG experienced no failure of any LED lamp at the station even though the bulbs have been turned off and on several times during the period. (Note: NYSEG recorded all incandescent bulb failures under normal operations at a comparable station and had approximately a 25 percent failure rate.) Both the LED bulb life, brilliance, and view angle proved to be acceptable to field personnel at NYSEG. (see Figure M)
NYSEG believes that even though the initial installed cost for LED lamps is much greater than incandescent bulbs, over the life of any substation, the cost of LED lamps for NYSEG's purposes will be much less than incandescent bulbs. There are less storage needs, reduced replacement time and much less current drain on the substation batteries. In addition, there should be less frustration during testing periods where bulbs are a key to what devices are in or out of service