Stadium lighting design considerations

Photo: On February 3, 2013, the Super Bowl site was suddenly powered off.

Next, the report of why the lights in New Orleans' Super Dome stadium suddenly went out filled the Internet.

One of the reports pointed out that the electrical equipment connected between the power company and the stadium had just been replaced in December of the previous year, so the power outage should be independent of the equipment. And after testing the stadium, it was found that there was no overload load during the game.

Another report mentioned that the leaders of the Super Dome stadium had paid close attention to the electrical system of the equipment before the game. Although they did not repair all the equipment, they had done a lot of maintenance work. The feeders of the stadium were tested and found to have power quality problems.

The final decision was made because the protection relay in the process of powering the stadium detected a problem and automatically shut down the system. Regardless of whether the main cause of power outages is equipment failure, improper maintenance or cognitive errors, this power outage has caused serious disruption of the game and economic losses.

Lighting method

This "Super Bowl" competition proves that it is necessary to provide appropriate emergency lighting in any level of sporting events. When it comes to lighting, indoor venues and outdoor venues require no dead angle switching.

Similar to other lighting systems, stadium lighting systems also require maintenance. Prior to the use of high-pressure gas discharge lamps, incandescent lamps were standard luminaires for stadium lighting. Today, stadium lighting standard lamps are metal halide high pressure gas discharge lamps. In most cases, a 400W, 750W, 1000W, 1500W or 2000W metal halide lamp is used.

However, there are still stadiums that continue to use probe start lights, and stadiums have been upgraded to pulse start lights in the last 20 years. There are also many stadiums that use magnetic ballasts designed for high-pressure gas discharge lamps. Table 1 shows the warm-up time, restart time, dimming, and full-spectrum performance comparison for different lighting technologies.

Table 1 Comparison of preheating time, restart time, dimming and full spectrum performance

Before each game, the competitor or stadium staff needs to test each group of high-pressure gas discharge lamps to ensure that the lamps can start normally and meet the lighting during the game. If there are too many lamps in the fault, they need to be replaced immediately. It is necessary to detect the lighting level and brightness of each position on the field to ensure that it can meet the needs of TV shooting. To illuminate all the lights before dusk, provide enough time for the inspection and adjustment of the TV camera. In addition, after the game is over, the staff needs to clean and organize the stadium and the auditorium, so it still takes hours of lighting.

Depending on the size of the stadium (such as a local college football field, basketball court or professional Super Dome), it can be powered by one or more power companies. The stadium is loaded with a large number of complex electrical loads, and although the outdoor load accounts for the majority, the load far exceeds these. The scoreboard system, broadcasting system, office equipment and air conditioning system inside and outside the stadium need to be powered.

Ways to reduce lighting interference

There are three ways to prevent the pressure difference of the high-pressure gas discharge lamp lighting system in the stadium, as shown in Figure 1.

Figure 1 Ways to reduce lighting interference

The first way: select several points on the power transmission line, and when the energy is exhausted due to power failure of the power supply system, energy supplementation is performed at these points;

The second way: adding a heat-triggered luminaire system to replace the high-pressure gas discharge lamp system;

The third way: choose a high-quality power supply to power the stadium.

Some details are described below.

1) Quality power supply contract

Many power supply companies can provide feeders with high reliability power. At present, this feeder has been upgraded, and a line can be specifically drawn from the substation, and one or two companies share one line. This feeder method already has a large amount of historical transmission data to prove its reliability. Users will pay a higher price for this service. However, the use of most venues and stadiums is not high, and the way to provide quality power is not the best option.

2) Install a thermal trigger for a high pressure gas discharge lamp

Many manufacturers offer an additional thermal trigger system for metal halide lamps. When the system senses that the luminaire is off, it will provide a high voltage start pulse to restart the luminaire. When the discharge tube of the luminaire breaks down, the luminaire can be warmed up again. The system itself needs to consume a certain amount of energy in the standby state, which reduces the energy-saving performance of the lighting system to a certain extent. The system is large and expensive, not suitable for all lighting fixtures, and some even require reinstallation of the fixtures.

3) Install an uninterruptible power supply (UPS) in the lighting system

The uninterruptible power supply solves a large number of power quality problems caused by line voltage faults. Some UPS manufacturers have produced dedicated uninterruptible power systems for high-pressure gas discharge lamps. It is not economical to install an uninterruptible power supply in all high-pressure gas discharge lamp systems. From the perspective of the size, frequency of use and economic impact on the customer of the integrated high-pressure gas discharge lamp system, the use of an uninterruptible power supply when the lamp is extinguished is not the best option. In addition, the use of uninterruptible power supplies adds extra load, takes up a certain amount of space, and requires increased economic investment.

4) Convert high-pressure gas discharge lamp system to other systems

Another possible method is to replace the existing high pressure gas discharge lamp illumination system with another system. However, due to the unique lighting requirements of the stadium lighting system, there are certain limitations in the selection of alternative lighting systems. Although there are only a dozen or so lightings for the competition each year, there are many other uses that require lighting. Therefore, reducing the energy consumption of the lighting system is absolutely advantageous for the stadium.

5) Full spectrum illumination is the lighting condition closest to daylight conditions

Today's TV lenses are fully digitalized on the basis of full spectrum illumination. The use of full-spectrum illumination will improve TV image capture technology and camera performance in motion field dynamics.