On the design of stadium lighting and electrical control-EEWORLD

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Abstract: This article introduces the design of stadium lighting and electrical control, analyzes the selection of lighting design standards and the calculation of lighting parameters, and clarifies the lighting quality standards, the classification and layout of lighting fixtures, and some issues that should be paid attention to in electrical control design.
Keywords: Stadium lighting design Electrical control design 1. The importance of stadium lighting For a modern stadium, not only does it require the building to have a beautiful appearance and a variety of complete sports equipment, but it also requires a good lighting environment, that is, it requires appropriate and uniform illumination and brightness, ideal light color, three-dimensional sense and no glare. In addition to ensuring that the audience has a good viewing effect, it must also ensure the lighting requirements required by referees, athletes and competitions, and should ensure a good TV broadcast effect. Lighting relies on the function of light to ensure that the light acts on the eyes of athletes, referees, and spectators and produces vision, so that everything on the sports field can be seen, such as the brightness of the venue environment, the color of the surface of objects, buildings, equipment and clothing, the shape and size of the viewing target, depth, three-dimensional sense, and the state of athletes during exercise and the atmosphere of the stadium, etc. Therefore, good lighting occupies an important position in modern stadiums. Generally, the following three factors should be considered in the lighting design of a stadium: 1. Meet the visual requirements of athletes during sports competitions and minimize the objective impact of lighting on the competition. 2. Meet the visual requirements of the audience and minimize the discomfort caused by lighting when watching the game. 3. Meet the lighting requirements of color TV broadcasts and improve the quality of broadcasts as much as possible. In short, lighting is closely related to the competition requirements of sports events and the viewing effect of the audience. A stadium without good lighting facilities is an incomplete stadium and will seriously affect its use function. 2. Stadium lighting design standards In order to obtain a good lighting design plan and reasonably use the distribution of light to meet the visual requirements of athletes, spectators, referees and good TV broadcast effects, it is necessary to first determine the lighting standards, including illumination standards and lighting quality standards. Lighting quality standards, including glare, light source color temperature and color rendering requirements, light directionality, energy saving requirements, etc. 2.1 Illumination Standard According to the illumination requirements recommended by the International Gymnastics Federation No. 83 and the provisions of Article 2.2.9 of the "Civil Building Lighting Design Standard" GBJ133-90, the following illumination standard recommended values are proposed? See Table 1. A few explanations: ?1 According to Article 2.2.9-1 of the "Civil Building Lighting Design Standard" GBJ133-90: The standard illumination value for football matches: when the viewing distance is 120m, it is 150~200~300lx; when the viewing distance is 160m, it is 200~300~500lx; when the viewing distance is 200m, it is 300~500~750lx. The viewing distance refers to the distance from the last row of the audience seats to the sideline of the field. ?2 According to Article 2.2.9-2 of the "Civil Building Lighting Design Standard" GBJ133-90: Vertical illumination required for television broadcasting: The maximum shooting distance is divided into three groups, ① For football events, the average vertical illumination should be 750lx when the maximum shooting distance is 25m; the average vertical illumination should be 1000lx when the maximum shooting distance is 75m; the average vertical illumination is 1500lx when the maximum shooting distance is 150m; ② For track and field events, the average vertical illumination should be 500lx when the maximum shooting distance is 25m; the average vertical illumination should be 750lx when the maximum shooting distance is 75m; the average vertical illumination is 1000lx when the maximum shooting distance is 150m. Each of the above vertical illuminations is used for a given sport level and a given maximum shooting distance relative to the 1.0m vertical plane value, and the intermediate values of each illumination value are used for other shooting distances. ?3 The above illumination refers to the final average illumination of the stadium. The initial illumination selected during design must be included in the maintenance factor, and the value of 0.7 to 0.8 can generally be used. ?4 Uniformity of horizontal illumination: Illumination uniformity is generally expressed as the ratio of minimum illumination to maximum illumination, or as the ratio of minimum illumination to average illumination. The ratio of minimum illumination to maximum illumination should be greater than 0.5. ?5 Uniformity of vertical illumination: The ratio of minimum illumination to maximum illumination should be greater than 0.4 to meet the requirements of the main television camera. 2.2 Lighting quality standards 1 Glare In addition to providing sufficient horizontal and vertical illumination, the key to sports lighting is to reduce glare, so as to achieve a bright and glare-free effect. Glare is one of the most important factors affecting lighting quality. According to CIE NO.83 publication "Sports venue lighting for color TV systems", the maximum glare index GRmax in the field should be less than 50. The smaller the glare rating GR, the better the glare limit, and the glare rating is 50. The glare rating GR is calculated by the following formula: GR=27＋24Lg?Lvl/Lve 0.9 ?1 In the formula, Lvl is the light curtain brightness generated by the lamp, and Lve is the light curtain brightness generated by the environment. Generally, when calculating the illumination, the glare rating GR in different directions should be calculated. When GR<50, it is feasible. In addition to reasonably determining the selection, installation height and arrangement of lamps, the limitation of glare can also take the method of improving the background illumination of the stadium. 2 Requirements for light source color temperature and color rendering In order to achieve a good color TV broadcast effect, the lighting quality of the stadium is not only related to the illumination, but also closely related to the color temperature and color rendering of the lighting source. Article 3.3.2 of my country's "Civil Building Lighting Design Standard" GBJ133-90 stipulates that the color rendering index Ra of general light sources for color TV broadcasting should not be less than 65. According to the requirements of CIE NO.83 publication and FIFA, the light source's correlated color temperature Tc is greater than 5000K and the light source's color rendering index Ra is greater than or equal to 80 to achieve the best on-site lighting effect and color TV broadcasting effect. 3 Directionality of light The depression angle of the lamp not only affects the vertical illumination, but also may have a greater glare effect on athletes, spectators and referees. For the lighting design of the ground stadium, the aiming direction of the lamp should be selected. In addition, the ratio of the light from the main camera to the other side should be controlled within a certain range, and the most important point of lighting is to set it in the center and restricted area of the football field. 4 Energy saving requirements Lighting energy saving focuses on the use of reasonable lighting solutions and efficient lighting devices, reducing line losses and good lighting control. Sports buildings are construction projects that consume a lot of electricity for lighting. From the perspective of energy saving, the lighting design that only compares the initial investment cost but not based on the lowest operating cost is not a reasonable design. The initial investment and operating costs should be considered comprehensively according to the specific situation. High-efficiency light sources and lamps should be selected, and accessories such as ballasts with low energy consumption should be used, and compensation capacitors should be added to improve the power factor of the system. The lighting design should have a variety of lighting modes and corresponding control schemes. By adjusting the number of lamps, suitable lighting can be provided for competitions and activities with different needs. The control scheme should be simple, practical, and flexible. 3. Calculation of stadium lighting design There are usually three methods for calculating the illumination of stadium lighting design: one is the unit area capacity estimation method; the second is the average illumination calculation method, which is used to calculate the average illumination on the illuminated surface; the third is the point-by-point calculation method, which can accurately calculate the illumination of a certain point. ?1 Basic formula for estimating unit area capacity: N=P×A/PL?2 Where: N—number of floodlights; PL—power of each floodlight?W; P—power per unit area?W/m2; A—illuminated area?m2. m=1/?η×η1×U×U1×K ?3
In the formula: m—simplification coefficient; η—lamp efficiency; η1—light source efficiency, 1m/W; U—utilization coefficient; U1—illuminance uniformity; K—lamp maintenance coefficient, generally 0.7~0.8. To simplify the calculation, the m values of different light sources are given according to η=0.6, U=0.75, U1=0.7, K=0.7, see Table 2. P=m×E?4 In the formula, E is the minimum illumination, lx. ?2 Average illumination calculation method, the number of lamps can be calculated using the following formula. N=E×A/η×F×K?5 In the formula: N—number of lamps?; E—surface average illumination?lx, from Table 1: A—illuminated surface area?m2; η—lamp efficiency; F—luminous flux?1m; K—maintenance coefficient, take 0.7~0.8. The above two illumination calculation methods are widely used, mainly used for illumination estimation, and are more suitable for scheme and preliminary design stages. ?3 The point-by-point calculation method of point light sources uses computer software to calculate point by point. The size of a floodlight is much smaller than the distance it illuminates, so the floodlight can be regarded as a point light source. The mathematical model for calculating the illumination of a lamp is shown in formula 6.
EΦ?cosα±?D/h ×sinα?Eh=ΨEh 6 In the formula, Eh: the average illumination?lx generated by a lamp irradiating a vertical vertical surface, Eh is calculated using formula 7: Eh=?Iθ×cosθ /R2?7 Iθ—light intensity in the θ angle irradiation direction?cd; R—the distance between the light source and the illuminated surface?m; h—the vertical calculated distance from the light source to the vertical vertical surface?m; D—the projection of R on the vertical vertical surface?m; α—the angle between the inclined plane and the horizontal plane, in degrees; θ—the angle between the center of the lamp beam and the horizontal plane, in degrees; Ψ—coefficient, Ψ=cosα±?D/h ×sinα. 4. Classification and layout of stadium lighting fixtures 4.1 Classification of lighting fixtures Stadium lighting fixtures can be divided into three categories: A, B, and C according to their beam shape, as shown in Table 3. In lighting design, appropriate lamps should be selected according to specific circumstances. Generally, for side lighting, the utilization coefficient of floodlights with fan-shaped beams (B or C) is higher than that of floodlights with cylindrical symmetrical beams (A). For four-tower lighting, the utilization coefficient of floodlights with cylindrical symmetrical beams (A) is higher than that of floodlights with fan-shaped beams (B or C). 4.2 Arrangement of lamps In order to effectively utilize the luminous flux of the light source, the size of the floodlight beam angle should also be selected according to the projection distance. According to the size of the beam angle, it can be divided into 7 categories, as shown in Table 4. 1 Four-tower lighting ① The position of the four-corner lighthouse should be selected in the space obtained by the extension line of the intersection of the two lines at an angle of 15° between the center line of the goal and the bottom line of the ground, and at an angle of 5° between the center line of the half court and the sideline, and the lighthouse should be set on the diagonal line of the venue. The floodlights are installed on four high towers. This layout is suitable for stadiums without canopies. The lighting utilization rate is low. In addition, the maintenance and repair of the lamps must be solved. ② The height of the lighthouse should make the angle between the lowest row of floodlights and the center of the venue and the horizontal ground of the venue within 20°~30°. Exceeding this range will not only greatly increase the cost of the lighthouse, but also reduce the ratio of vertical illumination to horizontal illumination, affecting the three-dimensional sense of the object shape and reducing the speed of identifying moving objects. The vertical height from the lowest row of floodlights in the lighthouse to the horizontal plane of the venue can be determined by formula 8: H≥L×tan25° or H≥0.4663L 8 Where: H—the vertical height from the lowest row of floodlights in the lighthouse to the horizontal plane of the venue?m; L—the horizontal distance from the center of the venue to the lighthouse seat?m. The relationship between L and H in the above formula can also be determined by the following ratio: when the angle with the horizontal plane of the site is 25°, L?H=2.145?1; when the angle with the horizontal plane of the site is 20°, L?H=2.747?1 ③ A lightning protection grounding facility should be installed on the top of the lighthouse, and the grounding resistance should not be greater than 10Ω. A red height indicator light should be installed on the top of the lighthouse, and there should be no less than 2 units. The terminal box installed on the lighthouse, the cables and wires laid are all provided by the lighthouse factory. ④ The location of the lighthouse and the projection angle and height of the lowest row of floodlights on the tower should meet the following requirements: α>5°, β>15°, 20°<γ<30°, 45°<θ<70° ?2 Hybrid lighting ① A lighting method that organically combines the light strip type and the lighthouse type. Generally, a type of lighting that solves the lighting technology effect of large-scale comprehensive stadiums is relatively good. ②Mixed arrangement, the projection angle and azimuth arrangement of the lighthouse can be appropriately and flexibly handled, the length of the light strip can be appropriately shortened, and the height of the light strip can also be appropriately reduced. 5. Stadium lighting power supply design? 1 The lighting power supply of the stadium is generally supplied by two power supplies from the low-voltage distribution room, which are mutually standby, manually and automatically switched. Usually, the two power supplies each carry about 50% of the load and are evenly distributed, so that when any one power is cut off and the extinguished lights have not been ignited, the venue can still maintain a uniform illumination distribution, so that general competitions can still be carried out. In addition, since the start-up time of the gas discharge lamp is about 4 to 8 minutes, and the restart time is about 10 to 15 minutes, even if two power supplies are used for automatic switching, the extinguished lights cannot be immediately ignited. Therefore, for the control room with someone on duty, the manual switching method of two power supplies can be used. For the control room without anyone on duty, the switching method of two power supplies with automatic switching but no automatic recovery should be adopted to ensure the normal progress of the competition and extend the service life of the light source. ① This power supply method does not need to consider the emergency lighting of the venue, and it can basically ensure the normal progress of the competition when the power supply is switched. ② The design of the power distribution system is relatively complex and the cost is correspondingly high. ③ When using four-tower lighting, the power cabinet is placed on the inner side of the bottom of the lighthouse, the power line is laid along the inner wall of the lighthouse, and the ballast box of the lamp is placed on the top of the tower. This power distribution method is more reasonable. ④ When using light strip lighting, the power is directly sent to the distribution counter on the canopy horseway, and the branch line of the power distribution can be laid in a metal wire trough rotating along the horseway. ?2 The switch of the competition light is mainly realized by AC contactor or contactless thyristor? SCR. Control with AC contactor is simple, reliable and economical; control with thyristor is advanced in technology, but more expensive. In order to facilitate maintenance and changes in lighting plans, it is advisable to use single lamp single control, or one switch can control 2 to 3 lamps, preferably not more than 3 lamps. ?3 When the gas discharge lamp is ignited, the impact current is very large. When turning on the light, the interval between single lamps should be 0.5s; when group control is used, the interval should be 10-30s. In addition, the stroboscopic effect of the gas discharge lamp has a great impact on the lighting quality. The gas discharge lamp powered by the AC power supply has a periodic stroboscopic frequency that is twice the power supply frequency. Stroboscopic will cause phantoms of rapidly moving objects. This effect has a great impact on video, especially slow motion video. When projected, it will show an unbearable flicker. Stroboscopic will also cause visual fatigue. It is usually measured by the fluctuation depth Fbd of the luminous flux. Fbd=?Fmax－Fmin /?2Fav ×100% 9 In the formula: Fmax—maximum value of luminous flux; Fmin—minimum value of luminous flux; Fav—average value of luminous flux. As long as the fluctuation depth is reduced to less than 25%, human vision will not produce fatigue effects due to stroboscopic. This can be achieved by changing the power distribution method. For example, adjacent gas discharge lamps are connected to power supplies with different phases; when designing the scheme, the overlap of the luminous flux emitted by gas discharge lamps with different phases can also be considered. In short, the impact of flicker on lighting quality must be considered in the lighting design of stadiums that use a large number of gas discharge lamps.
6. Stadium lighting control The main form of stadium and auditorium lighting control is centralized control by computer console in a dedicated lighting control room. The computer console is a human-computer dialogue form, equipped with a lamp position layout simulation panel, single light control, group control switch, etc. The layout of the single light control switch should correspond to the lamp position layout simulation panel. It can be controlled automatically or manually. The computer can simulate the on-site lighting status, automatically control and detect whether the lamps are working properly, and feedback to display the location of the faulty lamp group. Different control schemes can be set according to actual needs to meet the different requirements of different competition content and activity contrast and the different needs of different competition levels of the same sport. Several lighting schemes are determined in advance, stored in the computer after programming, and the corresponding lighting schemes are called according to different needs. 7. Conclusion The realization of a good stadium lighting environment mainly depends on the correct determination of the lighting design scheme, and at the same time depends on the selection of lighting equipment with excellent usability and lighting electrical control system. What is discussed here is only some superficial understanding, which needs to be further explored in future lighting design to explore its internal laws, make it further theoretical and systematic, so as to be more conducive to guiding practical work. The above is the author's superficial understanding of stadium lighting and electrical control design. Please correct me if there are any inappropriate points. References 1. "Civil Building Lighting Design Standard" GBJ133-90 2. "Civil Building Electrical Design Code" JGJ/T16-92 3. Japan Illumination Society. "Lighting Manual". China Building Industry Press. 1995 4. Li Gongwei et al. "Sports Building Lighting Design Manual". Atomic Energy Press. 1993 5. "Architectural Electrical Professional Design Technical Measures". China Building Industry Press. 2000 6. CIE Publication No83. "Guide for The lighting of Sports Events for Colour Tele-vision and Film Systems". 1989 7. CIE Publication No57. "Lighting for Football". 1983

Keywords：Lighting Reference address：On the design of stadium lighting and electrical control

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