With the extensive application of the new generation of information technology such as the Internet of Things, the Internet and cloud computing, smart cities have become an inevitable trend. In recent years, the New Deal of smart cities has been frequently issued, and the construction of smart cities in major cities in China has set off an upsurge. The Internet of Things technology is gradually applied to the construction of urban infrastructure, especially the relationship with urban road lighting facilities is increasingly close.

Street light is the carrier of urban lighting, and it is an indispensable facility in municipal road facilities and plays a pivotal role. Through the use of the function of communication Internet, the street light pole lighting system integrates functional lighting, video surveillance, traffic management, environmental monitoring, charging pile, public broadcasting, wireless communication and so on. At the same time, the problem of smart light pole power distribution is discussed and illustrated with engineering examples, which is convenient to promote and apply in the road lighting transformation of Haikou City in the future, and bring convenience to the work and life of citizens.

First, the concept of smart light pole definition

Smart light poles are a new type of urban infrastructure consisting of various sensors such as wireless communication of charging piles and electronic screens. Smart light pole is a "multi-purpose" multi-functional carrier, with the characteristics of "power supply, network, control", not only to realize the composite use of light poles, save urban land resources, beautify the urban environment, and smart light pole unique power, access to the network and other functions, can be used for the traditional power grid outside the coverage of the public area equipment and facilities power supply, network connection, forming a "city socket".

Second, the application advantages of smart light poles

① "a multi-purpose" smart light pole not only saves energy, but also reduces the occupation of urban land and promotes the efficient use of resources.

(2) Wide coverage, the coverage of street lights in the city's ground public infrastructure is more extensive.

3. Realize the integration of multiple functions.

④ Convenient construction and fast implementation.

Third, the functional design of the smart light pole

1) Smart lighting

The lighting function of the smart light pole is mainly composed of two parts: lighting system and platform software. The lighting system needs to control the lamps used to have a more energy-saving effect, and the platform software needs to control the light poles to be more intelligent. Intelligent regulation of the on, off and brightness of street lamps according to the traffic flow or the flow of people on the road and the lighting situation, ensuring that the brightness meets the public lighting standards, and avoiding excessive lighting, can extend the life of the lamps, realize the remote control, telemetry, remote information, remote viewing, remote adjustment of the lamps and lanterns, and transform the traditional manual inspection method into the system active alarm. Improve the quality and efficiency of daily operation and maintenance of street lamps, and reduce the cost and manpower and material resources of manual inspection.

2) Video surveillance

The video surveillance function of the smart street lamp needs to be reserved for the installation of a jack or interface on the smart light pole, which can be connected to the network and the power supply system and the camera. The video surveillance function is generally used in the intelligent police system, which can facilitate the real-time management and monitoring of the monitoring system.

3) Environmental monitoring

The smart light pole also has a certain environmental monitoring function, which can real-time monitor humidity, temperature, wind speed and direction, noise and so on. The installation port needs to be reserved on the light pole in the early stage to facilitate remote centralized management and control.

4) New energy charging pile

The new energy charging pile should be set up when there is a motor vehicle parking space on the roadside of the smart light pole, effectively solving the problem of land acquisition during the construction of charging piles and charging stations; When there is a non-motor vehicle parking space on the roadside of the smart light pole, electric vehicle charging pile is set up to solve the problem of electric vehicle charging. People can pay by scanning code, and the system realizes remote monitoring and management of charging piles.

5) Public broadcasting

The smart light pole can also set up the public broadcasting function, which requires a certain installation interface to be reserved on the light pole in the early stage, and the audio cable can be inserted into the light pole in the later stage to achieve public broadcasting access and real-time centralized management.

6) Wireless communication

The smart light pole can support wireless WiFi function and facilitate the installation of network equipment through the pre-reserved installation interface. Achieve free WiFi coverage of the street lamp coverage area, convenient for citizens to travel and browse the network.

Fourth, intelligent power distribution design of smart light pole

1. High pressure system design of smart light pole project

The street lighting system generally uses pre-installed substation (box-type substation) for power supply, and the high-voltage side distribution cabinet generally uses ring network cabinet. When the high-voltage in-line switch adopts the load switch-fuse combination electrical appliance, the isolation switch shall be installed on the power side to meet the requirements of Article 3.2.10 of the Design Code for 20kV and below substations (GB 50053-2013). When inspecting the fuse or load switch, there can be a clear disconnect point on the power side to ensure safety.

The main grounding types of urban 10kV distribution system are ungrounded, arc suppression coil grounding and small resistance grounding. According to the requirements of Article 4.4.2 of the Code for Design of Over-voltage Protection and Insulation Coordination of AC Electrical Devices (GB/T 50064-2014), when the time for effective grounding and low resistance grounding systems is less than 10s, the rated voltage of the MOA can be selected according to the formula (4.4.2-1). For non-effectively grounded systems, when the time for clearing the ground fault is less than 10s, the rated voltage of the MOA can be selected according to the formula (4.4.2-2).

Smart light pole distribution design

In the formula, UR is the rated voltage of MOA, kV; UT is the transient overvoltage of the system, kV.

2. Design of low-voltage power distribution system for smart light pole project

The load of intelligent lighting can be divided into street lighting load and intelligent facility load, the load level of general lighting load is three levels, and the load of ordinary intelligent facilities can be designed according to three levels. The distribution type adopts chain distribution, the box is located at the load center or the intersection of the main road, and the lighting cable and intelligent facility cable are laid along the road direction from the box to the box. Due to the common rod setting, the two power supply cables are laid through different protection pipes. The power supply radius of each power supply circuit is determined according to the cable carrying capacity, circuit voltage drop, and the sensitivity of the outgoing circuit breaker.

The low-voltage load of the box-type substation is mainly street lighting, intelligent facilities, and reserve load for landscape lighting, traffic signal systems, and advertising lighting. The low-voltage distribution system can be divided into low-voltage outlet circuit breaker, street lighting circuit breaker, intelligent facility circuit breaker, reserved landscape lighting circuit breaker, reserved traffic signal system circuit breaker, reserved advertising lighting circuit breaker. The circuit breaker of the street light distribution circuit should be equipped with leakage protection, which meets the requirements of article 10.9.3 of the Code for Electrical Design of Civil Buildings (JGJT 16-2008).

3, smart light pole project weak current engineering design

The smart lighting weak current project is mainly reserved for smart light pole video monitoring, environmental monitoring, wireless communication and other modules to facilitate access to the corresponding monitoring system at any time. At the same time, communication protection pipeline is laid to avoid repeated excavation in the future.

4. Domestic application cases of smart light pole project

There are many places in the country to achieve the use of smart light poles, mainly for the transformation of the original light pole or the whole pole new, the following two domestic application cases.

a, Guiyang Riverside smart landscape lighting project

The project was applied in 2017, as part of the urban strategic development of Guiyang City "build a new city, drain the old city", the comprehensive environmental improvement of Guiyang West Road was listed as a key project of Guizhou province and Guiyang City, and the transformed West Road will become the first riverside commercial pedestrian street in Guizhou province. With the smart garden light as the carrier, it integrates the intelligent control of the lamp body, water level monitoring, crowd density monitoring, face recognition, WiFi coverage, road intelligence information and environmental monitoring.

b, Xi 'an High-tech Zone smart lighting project

Applied in 2019, the first batch of smart street lights installed in Xi 'an, or even the entire northwest region, are loaded with functional modules such as LED lighting, 5G microbase stations, video surveillance, WiFi signals, environmental monitoring, intelligent manhole cover management, and parking space management. On the basis of completing lighting, other public services are also assumed. It realizes multi-pole integration, interconnection and multi-function in one pole.

Five, smart light pole project engineering examples

Take Haikou City Haifu Road reconstruction project as an example. On July 31, 2015, Haikou City held a mobilization conference to create a national civilized city and a national health city, announcing the official launch of the "double innovation" activities in Haikou City, Haikou will strive to take three years to hold back the "national civilized city" and "national health city" two golden signs. In July 2017, at the request of the Municipal Administration, the transformation of Haifu Road should be compared with the positioning of "international riverside garden city", and the road surface should be comprehensively upgraded. In September 2017, the Haifu Road renovation project was simultaneously designed and constructed within a month, and the design and construction was completed before the National Day on October 1, 2017.

Haifu Road renovation project, the total length of the main road is 4192.555m, the starting point pile number K0+000, the end pile number K4+192.555, the standard width of the road width 50m, belongs to the urban trunk road. Electrical engineering is mainly for the replacement of box-type transformer, street lighting trunk cable and street lamp wiring cable, replacement of street lamp pole, sidewalk garden lamp design.

In this project, garden lights are set up in the sidewalk section. The power of the lamps is 30W, arranged on the sidewalk side, the pole height is 4m, the basic spacing of the lamp poles is 20m, and LED light source is used. The garden lights are equipped with a smart lighting system in the design, and the specific functional requirements are as follows: The street light wireless network system is equipped with a high-speed communication network, which can provide wireless wifi connection signals. To achieve seamless mobile connection of the whole road area, reserved video surveillance interface, reserved electric vehicle charging pile, reserved public broadcast interface, to achieve a multi-purpose function. At the same time of laying the street lamp cable, two weak current protection pipes are buried to facilitate the laying of weak current pipelines in the later period. In addition, the box-type substation was replaced, and the high and low voltage power distribution was designed, and the low voltage load was based on street lighting and intelligent facilities, while the load was reserved for landscape lighting, traffic signal systems, and advertising lighting.

Vi. Conclusion

With the continuous development of urbanization, smart light poles will certainly be an important livelihood project in the future, in line with the high standards and high positioning of the construction of "smart city", and can comprehensively enhance the level of urban construction and influence. This paper describes some common contents in the design of smart light poles, providing some ideas and insights for the future smart lighting transformation of Haikou City, looking forward to the next few years, smart light poles can be deeply applied to the road lighting transformation of Haikou City, and fully build an international riverside coastal garden city.