Street lighting design for urban network reconstruction

! Planning and Design!

Street Light Reconstruction of Street Lights Wei Gongyuan Road lighting is an important part of the renovation of the city network at No. 165, Central Street, Liaozhong County, Liaoning Province. Since the reform and opening up, urban construction has developed rapidly, and new requirements have been put forward for road lighting that has a beautifying effect on cities. The design of urban road lighting should adapt to the needs of urban development. According to the characteristics of the road, the light source should be determined, the type of street light should be selected, and the position and control mode of the light pole should be arranged.

1 Light source for road lighting Urban road lighting should use high-intensity gas discharge lamps, such as high-pressure mercury lamps, high-pressure sodium lamps and metal halide lamps.

The high voltage beam lamp has the characteristics of high luminous efficiency, shock resistance, heat resistance, long life and power saving. However, the color rendering is poor, and it is suitable for use in roads, squares, stations, docks, construction sites and other places.

High-pressure sodium lamp has high luminous efficiency, small ultraviolet radiation, can be ignited at any position, has the advantages of shock resistance and long life, especially its strong fog-transparing ability, so it is especially suitable for road lighting.

The metal halide lamp has the characteristics of high luminous efficiency, good light color, small size, high power, small starting current, high stability against voltage fluctuation, and is an ideal third-generation light source, which is suitable for requiring high illumination and display. The illumination of the prosperous streets and overpasses with good chromaticity.

Road lighting fixtures Urban road lighting should use cantilevered high pole street lights. The cantilever type high pole street light is divided into three types: single fork type, double fork type and multi-fork type. In order to control the distribution of light flux, the inside of the lamp is equipped with a reflector. Lamps are often made of high-pressure mercury lamps, high-pressure sodium lamps or metal halide lamps. These lamps are classified into three types: cut-off type, non-cut type and half cut type.

The truncated light distribution is narrow, and the light distribution is mainly concentrated in the range of 0 to 60. The horizontal light is strictly limited, and glare is hardly felt, so it is suitable for high-speed roads.

The non-cutting type light distribution is very wide (the lateral direction of the lamp), and the glare is not limited. The light distribution is generally in the range of 0.~80., and the light intensity is high between 70.~80., 0.~70. It is weak, so it is suitable for busy streets or other places where bright is required.

The half-cut type is between the cut-off and non-cut-off type. The wide-voltage grade power supply link uses multiple 10kV power supply to improve the reliability of the power supply. At the same time, the time limit of 35kV voltage level relay protection is saved, so that the protection is more Selectivity, and correspondingly improve the reliability of power supply; 2 reduce the operation and maintenance costs of power customers' power equipment; 3 from the perspective of power supply companies, the electricity price of 10kV makes the power supply enterprises have greater profits; 4 uses multiple times 10kV power supply Reduce the investment of 35kV equipment for power supply companies and power customers; 5 give full play to the strong advantages of power supply technology expertise.

Disadvantages: 10kV power supply is higher than 35kV power supply line, and it is not economical when the power supply radius is large.

Combined with the development trend of the county power grid, the author believes that the 35kV voltage level should be phased out, and the second option is better. The reasons are as follows: 1 The larger power customers are closer to the substation, the line loss is not significantly reduced, and the density of the substation is gradually increasing; 2 the reliability of the power supply is improved; and the power supply link of the 35kV voltage level is reduced. More 10kV power supply improves the reliability of power supply; at the same time, the time limit of 35kV voltage level relay protection is eliminated, which makes the protection more selective and correspondingly improves the reliability of power supply; 3 reduces the operation and maintenance of power customers' power equipment. Cost; 4 From the perspective of power supply companies, the electricity price of 10kV enables the power supply enterprise to obtain greater profits; 5 the ability of large power customers to resist market risk 16 is poor, and it is easy to form idle assets; 6 with the deepening of power system reform The profit margin of power supply enterprises is shrinking, and the price advantage of 35kV power supply will gradually disappear; 7 large power customers use more 10kV power supply to reduce the investment of 35kV equipment for power supply enterprises and power customers; 8 the development of large power customers is subject to uncertain factors More constraints, power supply requirements for large power customers can be compensated by appropriately increasing the number of 10kV outlet circuits; 9 The ultimate combination point between power customers and power supply enterprises is the two-in-one economic power supply scheme that abandons the price of electricity; 10 is conducive to the rational allocation of human resources, giving full play to the strong advantages of power supply technology expertise.

5Using new technologies to improve grid stability and power quality An important feature of county load is seasonality, large day and night load changes, and the problems of grid stability and power quality are more prominent: First, make full use of the on-load The pressure transformer improves power quality; the second is to use power electronics technology to increase system transmission capacity, increase system stability and improve power quality. This is not only the cause of power planners, but also opens up a broad market for the electrical equipment manufacturing industry and is a way to develop high-voltage, high-capacity electronic equipment.

Used for general road lighting.

Street Light Arrangement 3.1 Street Light Arrangement The street light layout includes a single side cloth light, two side cross cloth lights, two side opposite cloth lights, T-junction street lights, cross street cloth lights and corner cloth lights, etc. The conditions are shown in Table 1. Table 1 Street lamp layout and applicable conditions Street lamp layout pattern Applicable conditions One-side cloth lamp pavement width is less than 9m, or the illumination requirements are not high, the cross-border road width on both sides of the road is greater than 9m, or the illumination requirement is higher. The two sides of the road are opposite to the cloth with the cross cloth, the T-junction, the street lamp, the busy T-junction, the busy intersection, the high pole lighting, the pole height is more than 20m, the corner of the road is curved (usually on the outside of the curve) The longitudinal spacing of the lamp on the curve with a small radius of curvature should be appropriately reduced.) Installation height, spacing and cantilever length of the 3.2 street lamp In order to reduce glare, improve the illumination quality, and avoid the roadside trees blocking the light, the installation height, spacing and cantilever should be considered. length.

For cantilever type high pole lights, the installation height should generally be more than 7m. If using cut-off lamps, the installation height! *", the spacing of the lamp posts should not be greater than 3 times the installation height; if non-cutting lamps are used, the installation height is >1.2", the spacing of the lamp posts should not be greater than 4 times the installation height; if a half-cut type lamp is used, Its installation height! > 1.2", the spacing of the lamp posts should not be greater than 3.5 times the installation height, the street lamp installation height! and the road calculation width" as shown.

The length of the lamppost cantilever should be determined according to the road width and the type of trees, generally 1.5-3.5m. The wiring of road lighting should be carried out by means of overhead lines or underground power cable lines. With the increasing requirements of urban construction, power cable lines should be the preferred wiring method. The advantage is that it does not occupy space and is conducive to urban beautification.

Power cable lines generally use the cylindrical space in the lower part of the pole as a junction box, wiring and installing electrical protection devices in the box, as shown. The power cable shall be laid in the cable trench, and the cable shall be buried directly in the ground. There shall be no joints in the underground part. The joint shall be installed in the lamp post box for inspection and maintenance.

The control of road lighting to control road lighting has previously been generally controlled by a combination of a photoresistor and a mechanical clock. Since the photoresistor is greatly affected by the weather, the control time error is also large, and the failure rate is high. With the expansion of the field of computer use, the microcomputer has been developed and produced for road lighting, neon lights, advertising sign lights, etc., which need to be turned on and off regularly. The time difference of the microcomputer time switch is less than 0.5s per day. It has the characteristics of not being afraid of power failure (internal automatic charging), small size, convenient debugging, flexible control mode, etc., and has been utilized in urban road lighting.

Road lighting is for pedestrians and vehicles. In the first half of the night, pedestrians and vehicles are more and need to be brighter. In the latter half of the night, pedestrians and vehicles are reduced. In order to save energy, the lighting is darker. This requires street lighting control devices. Reduce power or illuminate the dots. According to reports, there are computer-type street lamp control devices that have various functions such as lighting, interval lighting, and power adjustment. With the further development of computer technology, the street lamp control device that meets people's requirements and functions is bound to appear on the scene, bringing greater convenience to people. In the road lighting design of urban network transformation, computer type control devices should be given priority.

(:2004-03-26) (Editor Zhida in this column)

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