The Application of Tunnel Following Lighting Intelligent Dimming System in Highway

Xuewen Chen Fan Jiang Yuzhong Wang Ying Li

（1.Guangdong Yunmao Expressway Co.，GuangDong GuangZhou 525300；2.Guangzhou Bolu Electronic Technology Co.，GuangDong GuangZhou 510430）

Abstract: The development of highway tunnel lighting dimming energy-saving technology can effectively realize tunnel lighting on-demand adjustment,reduce power waste and effectively reduce operating costs.This paper introduces the specific application of tunnel following lighting intelligent dimming system in Guangdong Yunmao Expressway tunnel,analyzes its working mechanism and actual energy saving effect,which has practical reference significance to promote the technology of intelligent highway tunnel lighting.

Keywords: intelligent highway,tunnel lighting,intelligent dimming,LIDAR,energy saving,safety,application

1.Introduction

Good tunnel lighting environment is an important guarantee for safe traffic,tunnel lighting electricity expenditure is the main part of the highway electricity expenditure.How to ensure safety premise,reduce tunnel lighting energy consumption,to achieve "green,development,intensive,low-carbon" requirements,is the main goal of continuous optimization of tunnel lighting dimming control technology development.

Most of the existing tunnel lighting control mode for 24 hours hard open state,mainly using the level control mode.The mode of tunnel lighting power is always at the maximum,without taking into account the traffic flow of real-time changes in factors,in the second half of the night,low traffic hours still maintain high brightness output,and the traffic flow of smaller sections of the road section there is a large waste of electricity.In this regard,there is a need for real-time changes in traffic flow and other factors,the implementation of intelligent dimming tunnel lighting to achieve energy saving and cost reduction and efficiency.

Tunnel following lighting intelligent dimming system is a new type of intelligent dimming energy-saving technology.The technology can be a comprehensive combination of safety and energy saving needs,real-time positioning and status judgment of the vehicles driving into the tunnel,through the adjustment of the tunnel lighting power to achieve the purpose of automatic adjustment of the tunnel brightness,to achieve tunnel lighting automation,intelligence and information technology,is to promote intelligent transportation,green transportation construction of effective initiatives.

This paper combines the practical application of this system in six tunnels of Guangdong Yunmao Expressway,which will be opened to traffic in 2021,and provides reference for the design of tunnel lighting control technology for new and operating expressways by studying and analyzing its energy-saving mechanism,system reliability,safety,and economy.

2.Project Application

Yunmao Expressway is an important project of the 13th Five-Year Plan of Guangdong Province,located in the remote mountainous area of western Guangdong Province,which is important for poverty alleviation and poverty alleviation.In order to respond to the national energy-saving strategy and achieve the goal of "carbon neutrality",Yunmao Expressway has selected six tunnels in Zhuwaling,Huanglou,Nanzhai,Chashanling,Xinya and Jinlin to apply the tunnel following lighting intelligent dimming system.

2.1 Working Principle

The system is deployed outside the tunnel cave fixed,longitudinal deployment of mobile LiDAR car detector in the cave to monitor the vehicle in real time,through the specially developed intelligent controller for real-time management of tunnel lighting,to achieve segment independent dimming control.

Figure1.System workflow diagram

Figure2.System working operation diagram

Figure3.Dimming system schematic

When there is no vehicle into the tunnel entrance or the tunnel without car traffic,vehicles away,LiDAR car detector to get no car traffic signal,the system through and the original tunnel lighting system controller signal connection to control the tunnel lighting fixtures,so that the lighting fixtures in the original tunnel lighting controller set power based on,again reduced to the whole value;when there are vehicles close to the tunnel entrance and in the process of driving in the cave,LiDAR car detector to obtain a vehicle signal,the system controls the tunnel lighting fixtures to restore the original set power of lighting fixtures,vehicles continue to pass through the tunnel longitudinal distribution of different LIDAR car detector,the system will follow the vehicle trajectory to restore the tunnel lighting fixtures to the original set power,brightness segmentation to restore the original brightness,to achieve "car light,car light dark ",on the basis of ensuring traffic safety,to obtain the maximum energy-saving effect.

In case of emergency,such as equipment failure or vehicle accidents in the tunnel,the following lighting intelligent dimming system starts its site emergency control system,to exit the dimming mode and adjust the working state of the lighting system to the full-open state of the lamps,ensuring the safety of traffic.

The system workflow diagram is shown in Figure 1.

The schematic diagram of the system operation is shown in Figure 2.

2.2 Overall System Architecture

The main components of the tunnel following type lighting intelligent dimming system are shown in Figure 3.

(1) Outside the cave fixed LIDAR vehicle detector:detect whether the vehicle enters the tunnel.

(2) Mobile LIDAR vehicle detector inside the tunnel: detecting the vehicle condition inside the tunnel.

(3) Data acquisition and dimming machine: analyze the radar vehicle detector data,and carry out commandtransmission and dimming operation.

Table1.Volume of traffic and power consumption when the system is turned off

Table3.Relationship between traffic flow and electricity consumption

(4) Tunnel real-time condition monitoring software platform:installed in the monitoring center to achieve remote monitoring,early warning,manual intervention,etc.

2.3 System Features

The tunnel following lighting intelligent dimming system is innovative,advanced and unique in that.

2.3.1 Tunnel safety lighting dimming technology

Tunnel following lighting intelligent dimming system for the vehicle driving into the tunnel to locate and do state judgment,when the tunnel is not car traffic,the system in the original dimmable lamps and lanterns control circuit,superimposed on a dimming voltage to control the lighting power,so that the brightness is reduced to the set low level;when the tunnel has a vehicle traffic,the system gradually restores the brightness to the original set brightness level,to achieve The intelligent control of "car light,car light dark".

If a vehicle stays in the tunnel or congestion,system failure and other emergency situations,the system emergency control system automatically starts to restore the working state of the lamps and lanterns to adjust to the original tunnel lighting controller set power,to ensure the safety of traffic,the system will be in the software platform for early warning,to remind the monitoring personnel attention.If the emergency control system fails,the dimming function can be turned off remotely through manual intervention,the lighting system will also return to the original brightness state.

2.3.2 Vehicle precision detection and positioning technology

The accuracy of vehicle detection and positioning directly affects the energy efficiency of the system,and even traffic safety.Tunnel following lighting intelligent dimming system follows the vehicle dynamics in real time(mobile LiDAR scanning tunnel range of 150-200 degrees per second),tunnel monitoring of all-round coverage,real-time monitoring of the tunnel traffic flow,car trouble,parking and other events,accuracy of 99%;LiDAR car detector failure can be real-time warning through the software platform.Dimming signal generator and computer 10 times per second"handshake" signal,more than 1 second no"handshake" signal,will trigger the emergency mode,the tunnel lighting will be restored to full brightness mode until the signal recovery.

2.3.3 Segmented dimming control technology

The lighting of the long tunnel is controlled independently in sections,and the software algorithm combined with the radar car detector data to realize "the light of the incoming car is on,and the light brightness is automatically reduced when the car leaves",effectively saving energy.

3.Effectiveness of Project Implementation

3.1 System operation

The tunnel following lighting intelligent dimming system was put into use in June 2021,the overall operation of the system is stable,the performance indicators meet the design requirements,to meet the expected requirements.

3.2 Energy saving effect of operation

This system is applied in a total of 6 tunnels in Yunmao Expressway.To test the energy-saving effect,Huanglou Tunnel is selected as the test tunnel (995m in the left lane and 955m in the right lane),and the energysaving effect is evaluated by counting the electricity consumption of lighting under the function of turning on/off the system.

Test program: during July 5 to July 18,2021,any four days (July 8 -July 11) selected to turn off the tunnel following lighting intelligent dimming system,the rest of the time to turn on the system,the collection of tunnel traffic and electricity consumption data (see Table1.).

From Table1,it can be seen that:

(1) When the system is turned off,the power consumption of the tunnel is not related to the traffic flow,and the power;

(2) When the system is turned on,the power consumption of the tunnel is related to the traffic flow;less traffic means less power consumption;

(3) Traffic flow and power consumption are not simply linearly related.

The length of the left and right lines of the Huanglou Tunnel is close to the installed lamps and dimming system equipment is the same,and the difference in power consumption between the left and right lines when the system is closed is not significant,so a comprehensive comparison can be made,with traffic flow as the main reference factor.

When the traffic volume is about 3000 vehicles/day:

When the traffic volume is about 3150 vehicles/day:

From the test data in Table 1 and Table 2,it can be seen that the average energy-saving rate of the system is higher than 30% during the test period.

The energy-saving efficiency of the system is related to the traffic flow.When the traffic flow is about 3000 vehicles/day,the energy saving efficiency is 30% to 37%during weekdays;when the traffic flow is about 3150 vehicles/day,the energy saving rate is 30% to 25% during weekdays.Assuming an approximately linear relationship between traffic volume and energy savings,the energy savings rate decreases by 5% for each 5% increase in traffic volume at a base of 3000 vehicles.

The system energy savings rate is also related to the traffic distribution of the tunnel.For example,the energy saving rate was only 24.75% on July 17 when the traffic flow was at 3116 vehicles,and rose to 29.78% on July 12 when the traffic flow was 3218 vehicles.According to the actual situation,the traffic flow is generally concentrated in the morning and evening commuter peak,then the increase in traffic flow on the energy-saving efficiency is not much,because a car through the tunnel and several cars through the tunnel at the same time,are required to restore the original lighting brightness,the system does not dim.Therefore,in order to data rigor and practicality,in the analysis of the tunnel following the intelligent lighting dimming system energy saving rate,not only the traffic flow as the main basis for measurement.

4.Conclusion

By applying the following lighting intelligent dimming system in the highway tunnel,using advanced radar vehicle detector to sense the real-time situation of vehicles,with data processing technology as the core,the application of vehicle identification,vehicle tracking,track tracking,state identification and other technologies,can realize the full automation of tunnel lighting dimming,effectively enhance the tunnel intelligent dimming intelligence and comprehensive management level,can solve the tunnel lighting electricity energy waste and other issues.The successful application of the following lighting intelligent dimming system in Yunmao Expressway tunnel can provide a reference for operating tunnel lighting safety and energy-saving transformation and new tunnel engineering mechanical and electrical design,promote the development of tunnel operation safety and intelligent energy saving,and guide the application in highway toll station square,service area and other multi-scene.Therefore,it is an effective exploration of intelligent transportation technology applications.