Overvoltage protection for LED lighting systems
For over 80 years, ABB has been building and offering surge protective devices for protection of electrical and electronic equipment. Today, ABB also offers full solutions for LED lighting systems.
There are nearly 300 million streetlights in the world with some 90 million in Europe alone. In Poland, for example, there are nearly 3.3 million street lights consuming 1,500 GWh annually (according to the National Fund for Environmental Protection and Water Management). Sodium vapor lamps account for 65% of these. Mercury vapor lamps, incandescent lamps, neon lamps, and other types account for the remaining 35%. Presently, these light sources boast about 40% efficiency.
The global trend shows that street lighting is upgraded with LED (light-emitting diode) technology. In France, 10% of lighting installations are replaced with LED lights every year. It is estimated that by 2020, as many as 50% of all installations will have been replaced with LED technology.
LED technology provides a versatile light source with long service life (often as long as 100,000 hours), that meets the joint requirements of cost reduction and energy efficiency. The extent of cost savings depends on the currently used lighting system, and amounts to 60–90% compared to conventional in- candescent lamps, sodium or mercury lamps, and to 10–20% compared to energy-saving CFL lamps.
Due to the low energy consumption, LED lamps contribute to the reduction of the number and diameter of copper cables which results in cost savings on the whole installation. Low operating voltage (<32 V) prevents the risk of electric shock, minimizes the amount of generated heat, ensures better resistance to temperature variations, vibrations, and impacts. LED technology is suitable for applications requiring lighting intensity controls (dimmers), room occupancy sensors or time switches, which adds to power consumption.
There are, however, some weaknesses to LED lamps. Their biggest weakness is low resistance to over voltages in the power supply network and in the light intensity control system. Over voltages could result in permanent damage to the power supply, control electronics, or the diode, or they might result in their premature aging. Electronic devices, such as LED power adapters, are capable of withstanding over voltages of up to 1500 V AC and require protection against transient overvoltages generated by industrial installations or lightning strike. The best solution to this technical problem are special surge arresters.
ABB has joined forces with the main market players (lighting appliance manufacturers, fitters, lighting unions, etc.) to propose a full range of surge protective devices for installation at various points of the LED street light power supply network.
To protect public lighting equipment, it is recommended to install two to three surge arresters as close as possible to the sensitive LED lamp in the cabinet of the lighting mast or traffic lights as well as type 2 surge arresters in the power supply switchboards.
For close equipment protection – SPD Type 2+3
OVR T2-T3 N1 15-275S SL LED lamp surge arrester limits voltage surges occurring between the line (L), the neutral (N) and the Earth (PE) to Up = 1.1 kV at rated discharge current In = 5 kA. Maximum discharge current Imax is 15 kA. The unit is provided with two varistors protecting the system against over voltage. If one is damaged, the other continues to protect the equipment until the surge arrester is replaced.
Due to its highly compact size, the unit can be easily integrated in lamp posts and in small power supply boxes with DIN-rail mounting. The surge arrester is provided with an end of life indicator that allows preventive maintenance. IP32 protection class ensures higher resistance to severe weather and dirt conditions. In fact, the product is placed in the bottom of the pole where it is dirty and sometimes even with small animals. Bottom connection of cables eliminates condensation issues. The phase and neutral cables (with a length of 17 cm) are already connected inside the product housing to reduce the technicians’ time. The surge arrester requires installation of additional safety feature in the form of either a gG or gL fuse link, or a B or C trip type circuit breaker rated at < 20 A.
For protection of general power supply cabinets — SPD Type 2
OVR T2 3N 40 275 P LED lamp surge protector limits voltage surges occurring between the line (L), neutral (N), and the Earth (PE) to Up = 1.4 kV at rated discharge current In = 20 kA. Maximum discharge current Imax is 40 kA.
The unit is equipped with plug-in cartridges that can be replaced without cutting off the power or disconnecting wires. It is DIN-rail mounted and provided with an NO/NZ auxiliary contact (TS) that — combined with the end of life indicator — facilitates condition monitoring.
The surge protection device requires installation of additional safety feature in the form of either a gG or gL fuse link, or a B or C trip type circuit breaker rated at < 50 A.
Whether installed in the switchboard or a LED street lamp post, the OVR ensures protection and continuity of operation of lighting systems in public and private areas (streets, car parks), as well as street furniture (bus shelters, billboards, decorative lighting), and light bollards ensuring road traffic safety