EVOC Highway Tunnel Power Supply and Distribution Monitoring System

 Highway tunnels are usually situated in distant, mountainous areas, so their power supplies feature an ultra-long-distance coverage and the distribution monitoring systems have to detect a multitude of objects. This calls for careful planning, design, selection and implementation. The system in this case is a result of EVOC’s intensified R&D efforts and years of design, manufacturing and construction experience in the power automation monitoring industry. This system is developed based on various technical specifications and standards, and put forward with a view to highway tunnel monitoring characteristics.


The requirements of power supply and distribution monitoring system for highway tunnels

The system should provide real-time and centralized management of power supply and distribution at each section of highways, real-time tracking of the information gathered at the front end of tunnels, and a good automatic alarm-sounding management platform. With various monitoring and protection devices fitted at the front ends of tunnels, it is possible to collect the operating status of power supply devices for lighting and ventilation, and to monitor the incoming line, outgoing line, and circuit breakers of switchboards. The system collects the information on malfunctions, and thus quickens the response to accidents and reduces power outages caused by malfunctions. Via the master stations at the monitoring center, it is possible to operate remote switches and contactor loops. Real-time monitoring of busbar voltage at various levels/sections boosts acceptability of voltage and reliability of electrical equipment. Its acquisition of electrical energy and kilowatt-hour deliver a full knowledge of the various loads, changes of total load and electricity costs.

The highway tunnel power supply and distribution monitoring system ensures the safe and reliable running of highways. The front ends mainly monitor the following:

1.  Tunnel lighting system
a) Remote monitoring: it checks the lighting switches, actual current loading in real time and serve as status indicator.
b) Remote control: it controls the switching of loops, with AC contactors.

2.  Tunnel ventilation system
a) Remote monitoring: it checks the on/off status of ventilation machines in real time.
b) Remote control of rotation direction.
c) Remote control: it controls the switching of loop of ventilation machines via AD contactors.

3.  Low-voltage switchboard: it checks loop voltage of the female bank. It checks 1 set of each transformer, including all the three phases (A, B, C).

4.  High-voltage switchboard: it checks high-voltage incoming line, the switching status of outgoing line breakers. It checks the status, but dose not control them. Master incoming line: power on/off judgment by high-voltage power indicator.

5.  ATS: It checks the ATS automatic switching devices.

6.  UPS: It checks the operating status and parameters of the internal gadgets, including the rectifiers, inverters, batteries, bypasses, loads and so on. Once a status change of gadgets occurs or an operational parameter exceeds the ceiling, the system sounds the alarm automatically. Besides, it tracks various UPS parameters, including various voltage, current, frequency, and power, with illustrative displays. 

7.  Generators: It collects and monitors the operating status in real time via protocols.

System Structure

Highway tunnel power supply and distribution monitoring system adopts a 3-tiered structure, which includes central tunnel host station, local tunnel administration station and the monitoring devices at the front ends of tunnels.

The 1st tier: the central tunnel administration station consists of servers, administration software system, database, and minimized alerting system. It administrates the whole tunnel power supply and distribution system on the road.

The 2nd tier: the local tunnel administration stations of sections. For better management of the tunnels along the roads which extends more than 100 kilometers, the concept of section is put forward. The local administration stations are responsible for running the power supply and distribution monitoring system in their sections.

The 3rd tier: the monitoring devices at the front end of tunnels. They include the monitoring host computers installed in the substations of tunnels, smart equipment monitors and various kinds of power distribution checking and control modules. The 1st tier and the 2nd tier are integrated together with trunk fiber Ethernet, while the 2nd tier and the 3rd tier are linked to the whole system by TCP/IP protocol-based networks within the sections.


Diagram 1. Highway Tunnel Monitoring Management System Architecture


The servers at the central monitoring center are responsible for communicating with on-site monitoring host computers. The servers convert the different kinds of IP data packets (including warning data, run event data) they received into standard formats acceptable to internal information mode of the administration center and then, route them to operation monitoring platform. The servers also route the equipment control commands, setup commands and queries sent from operation monitoring platform to the monitoring host computers for performance.

The operation control platform lies at the heart of daily operation and maintenance. It delivers video maps, and video, audio, writing expressing. It also features audio and light alerting, mobile phone alerting, and voice phone call alerting. It is capable of presenting in various forms the warning against objects, operating status, current equipment parameters, equipment status, and the analysis of historical data and so on. It also accepts mouse or keyboard commands from administrators, and route the commands concerning equipment remote control, parameter setup, system maintenance, software update, to on-site monitoring devices via communications servers.

The monitoring center is composed of the following equipment and systems.

  •  1 x server (industry standard server, Windows 2000 Adv Server network operating system, SQL Server network database system, GNC-Manager network administration software, automatic alerting hardware) 
  •  1 x operation platform (industrial PC, Windows 2000 Pro operating system, network administration software terminals)
  •  1 x laser printer (optional)
  •  1 x 100M Ethernet switch (optional)


The monitoring hardware at the front end of tunnels consists of monitoring host computers, smart equipment monitors and different kinds of 485 check and control modules, including network monitoring host computers, voltage transmitters, current transmitters, universal input/output modules (which checks knife switch status and output control), power supply controllers and smart equipment monitors etc.

The topological graph of a typical tunnel front end monitoring network is as follows.



The monitoring host computer at the front end checks all operational status of the smart equipment at the substations with smart equipment monitors. By collecting the communication protocols, they route the data to the monitoring for real time management via the IP network.


Monitoring host computers, coulant meters, voltage transmitters, current transmitters, universal input and output modules, power supply controllers do the sampling and control management. They can check the switch status of lighting system (by checking the power supply) and the operational status of ventilation machines on a real time basis. Power supply controllers can remotely control the switch of lights. And universal input and output modules can control rotation direction of ventilation machines.

Different kinds of electricity modules, such as voltage transmitters, current transmitters and coolant meters, are used to collect the electricity data at the substations, such as low-voltage incoming three-phase voltage data.


Input and output modules are used to collect the switching status of major power distribution equipment, such as high-voltage master incoming line breaker, as well as fault status.


Collected by the check and control modules are the transient electricity (three-phase current, three-phase voltage, active power, reactive power, active energy, reactive energy, power factor, frequency etc.), the status of loop breakers, and loop faults. This information will be uploaded to monitoring host computers via 485bus for processing, and will be transmitted via IP network protocol, to the administration center for build-up of database. There, configuration software processes the information to run screen display of operational status, analyze data, automatically create graphs and a check list of historical records, print reports, and sound the alarm for overload, accidental trips and unbalanced three phases. Thus, workers on duty are able to do load analysis, reasonable deployment, remote switching on and off, as well as timely trouble-shooting. Hence, the modernized administration of power distribution system is realized.


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