Overall design of networked real-time street lamp precise monitoring system

The realization of digital, networked, real-time, precise and dynamic urban public road lighting systems is an inevitable trend in the development of street lighting systems, and an inevitable trend and requirement for economic and technological development. This paper introduces the characteristics of the new street lamp monitoring system-network real-time street lamp precise monitoring system (MRL, real-: imenetworkingsystemforaccuratelyMonitoringRoadLamp), discusses the overall system framework and related core technologies, and discusses the basic functions of the system. On this basis, a specific implementation method of the road segment controller is given.

1MRL system features and overall frame design 1.1 Street lighting system status With the development of the economy, urban street lighting has begun to appear street lighting nightscape, lighting scale, system complexity, system automation and new lighting. The management methods, operation methods and maintenance methods of the original municipal street lamp system have not been able to meet people's requirements for street lighting quality, maintenance level, energy conservation and environmental protection. 4.1 million baht, about 4.5 million baht nationwide. With the deepening of opening up to the outside world, beautifying the city's night scene has become an important means of establishing a city image. This not only makes the number of lamps in various cities continue to grow rapidly, but also new types of lamps, new types of poles and new types of transformers are constantly being updated. More importantly, people are dealing with accident speeds in urban street lamp management systems, timely and accurately grasping system operating status information, and adjusting them reasonably. New higher requirements have been put forward in terms of urban lighting load and energy conservation. Although some developed cities have carried out a certain degree of system transformation, for example, some systems realize the functions of three remote “ie, telemetry, remote control, and remote signaling”, and some systems control and detect the contactors through light control and time control technology. The lighting rate of each section can effectively control the night or midnight light, and can promptly alarm the sudden events such as short or open circuit of the power supply transformer (current or voltage), and some systems realize the double light single light. Some systems use GPS and GIS technology. However, these systems do not realize digitalization and networking of digital ballasts at all, and cannot realize remote monitoring of lamps at any time and any time.

Theories, technologies and products with characteristics of practicability, advancement and reliability have been developed on the basis of a large number of practices. It embodies the superiority of key technologies, and its main features are reflected in the following points.

The lamp illumination is adjustable and constant power output. The ballast adopts microprocessor-based all-digital ballast technology (active power factor correction technology, high-frequency soft-switching technology and frequency sweeping technology, etc.), which can not only control the illuminance of the lamp as needed, but also the voltage amplitude of the distribution network. In an environment where the value fluctuates greatly, the lamp is guaranteed to have a constant power, and the nominal service life of the lamp is truly achieved.

Networked control of any lamp. At present, the general streetlight network control is mostly the control of the whole road section or the double-light single-lighting. "The control strategy for any single-turn luminaire and its combination cannot be realized at all. The MRL system is based on digital ballast technology, power carrier communication technology and GSM (Global System for Mobilecommunications) wireless communication technology, can control single-turn lamps and designated segment lights at any time.

2D (Plane Geographic Information) + D (Street Light Attribute Information) interactive control. Through GIS (GeographicInformation System) technology, the municipal street lamp official office can accurately understand the position information and operation status of each street lamp transformer and each street lamp in the city, visually grasp and process various related attribute information of the city street lamp system, and realize real-time dynamic information display. And control.

Accurate energy metering and real-time fault alarms. By adopting the digital energy metering chip CS5451 and digital ballast, not only can the line power quality and power consumption be accurately grasped at any time, but also the power consumption information of each street lamp can be known. When the luminaire and communication line are faulty, the street lamp management office can get a timely fault alarm.

The overall framework of the MRL system At present, China's traditional manual street lighting control, timing control, artificial street lamp inspection and other work methods can not meet the needs of modern national economic development, and can not meet the requirements of digital city information sharing and utilization. The use of computer control technology, various network communication technologies, wireless communication technology, GSM technology and GIS technology to achieve remote and accurate dynamic management of urban street lamps has become the basic requirement of modern digital city municipal street lamps, and is an important content of urban green lighting projects.

The overall framework for MRL networked real-time streetlight precision monitoring systems. It mainly includes 5 parts of digital ballast module, power carrier communication module, GSM module, link controller module and GIS-based computer management system.

Digital ballast module. It is the hardware foundation for the measurement and control of single xenon lamps, using the latest achievements of modern power electronics technology (active power factor correction technology, high frequency soft switching technology and high frequency magnetic technology) and advanced integrated control chip (power factor control) , power device bootstrap driver), high-voltage trigger start circuit designed by adaptive technology and acoustic resonance elimination circuit designed by frequency sweep technology and PID constant power closed-loop control circuit, with hot lamp start, lamp short circuit, lamp open circuit and lamp damage Such protection measures can adapt to long-term stable work under the harsh environment of outdoor weather and unattended conditions.

Power carrier communication module. Although PowerLine Communication (PLC) has various problems in long-distance communication, some problems are still difficult to solve, but for street lamp management systems, since each lamp requires 220V cable power supply, the topology Relatively simple, the network load is single, and communication is only between the link controller and the street lamp, and between the street lamp and the street lamp. Therefore, the power carrier communication has great convenience and feasibility. The system also adopts self-organization theory to dynamically detect the logical topological relationship of street lamp nodes, establish a logical link communication layer, overcome the shortcomings of low efficiency of point-to-point communication of power carriers in the past, and ensure the response time of street lights at the end of the system.

Road segment controller module. Also known as Remote Terminal Equipment (RTU, RemoteTerminalUnit), it is the daily operation control center of the whole system. It can work under the control of the municipal street lamp management center control computer (hereinafter referred to as the upper computer), or it can work independently from the upper computer. It not only directly controls the power supply of the street lamps and has the operation monitoring function, but also has various street lighting control strategies, including: 1 automatic timing control, which can control the street lights according to the preset time of the street light switch; 2 automatic sunshine control, The street lamp can be automatically controlled according to the actual measured daily illumination and illumination control criteria; 3 based on the timing illumination control, on the basis of the automatic timing, the street lamp can be flexibly controlled according to the special change of the actual illumination; 4 special holiday and special demand control, the road section The controller can receive the commands issued by the street lamp management center, and arbitrarily control the power supply of each phase of the transformer and the work of each street lamp.

In addition, it includes functions such as energy metering, work environment monitoring, information communication, fault status alarms, and manual control.

GSM module. There are dozens to hundreds of road controllers in a city. How to form a network with the street lamp management center computer reliably, conveniently and economically is the key to efficient and stable operation of the street lamp system. The use of telephone lines is unrealistic for practical systems. It not only requires telephone lines for each road segment controller, but also has high operating costs. Although digital radio stations are easy to install and use, there is no operating cost on the surface, but in reality, the city The spatial layout changes rapidly. To build a communication network that is as reliable as mobile communication, not only is the construction cost high, but the maintenance cost is also very impressive.

The same similar problem exists with wireless local area network WLAN. The GSM system solves the above problems well in the street lamp management system. Electrical quality and line load must be able to reliably detect faults such as short circuits and open circuits on the power supply line.

It must be ensured that the system can measure the daily illumination, control the system power supply according to the actual illumination and the timing switch light control requirements, and ensure the lighting effect in the climatic environment such as rainy days and sandstorms, and improve the overall lighting quality.

The system must be guaranteed to work properly over a range of temperatures and humidity. Therefore, in addition to reliability in terms of device selection and software design, there must be means for hardware to detect temperature/humidity and methods for adjusting temperature/humidity.

In addition, in order to ensure the reliability of the section controller operation, it is also necessary to consider various electromagnetic interferences caused by the strong current system to the weak current system and the crosstalk of the power grid. 5) GIS-based computer management system. The GIS system is an important technology for the overall design of the 2.2-segment controller hardware in recent years. It has been well applied in many fields. In the MRL system, the computer in the central monitoring room can grasp the actual situation of the street lights in the city in real time. The electronic map can manage the work of the whole system and dynamically display the location and cause of the damaged street lights. These basic functions are completed by a controller installed on the street lamp power supply line. The controller receives the commands from the control center through GSM, and then sends the results back to the control center for centralized processing of the information.

The overall design of the 2-segment controller 2.1 Functional requirements For a networked real-time street lighting monitoring system, the road segment controller is the nerve center of the entire system, the lighting rate of each road section, all night or midnight light control, power supply transformer (current Emergency alarms such as short circuit or open circuit are completed under the direct command and control of the road segment controller. Therefore, the requirements of the entire system for the segment controller are very strict. The main requirements are as follows.

It must be ensured that the system can be single-phase/two-phase/three-phase independent remote or local control. The street lamp management system can control the working state of the transformer arbitrarily in the office of the municipal street lamp management office, or can control the operation of the transformer and the street lamp node arbitrarily according to the control strategy under the control of the local microprocessor.

It must be ensured that the correct working state can be correctly entered at any time after the system power-on reset. This requires that the segment controller not only has a clock system, but also a multi-level backup system to ensure that the system segment controller and the host computer communicate normally when the circuit is powered off, and that the clock is normally operated when power is lost for a long time; The system records operational information and lighting control strategies at all times, and in the worst case, implements a local manual control system.

It must be ensured that the system can accurately measure the overall structure of the power supply transformer section controller as shown. It mainly includes five modules: high-power control and detection module, energy metering module, control strategy and clock monitoring module, power carrier communication interface module and GSM communication module.

1) Power control and detection module. On the basis of the automatic air switch, the road section controller adopts two-stage control mode of solid relay and AC contactor for the power supply line control; the voltage transformer and the current transformer act as the metering sensor and also act as short-circuit and open-circuit detecting sensors. In addition, the module achieves effective isolation of strong and weak systems.

2) Energy metering module. The segment controller adopts CRYSTAL's latest three-phase power/energy metering integrated circuit chip CS5451 with serial interface. This chip is easier to implement with microprocessor than the current popular electronic meter chips such as AD7750 and AD7755. connection.

The clock module uses the DS1302 chip, and uses a 3.3V lithium battery as the clock backup power supply to ensure that the long-term power-down clock information is not lost. The I2C bus-type 64Kbit electrically erasable memory EEPROM can store about 1300 ballasts for a long time. Record information. In addition, the power supply and charging module will provide a backup power supply to the system. When the road segment controller is powered off, the upper computer can still know the status of the link controller in time.

The power carrier communication interface module is as shown. The module uses spread spectrum communication technology based on the CEBus standard to comply with existing industry standards. The core chip adopts Intellon's spread spectrum power line communication transceiver SSCP300. Its standard and CEBus standard are both. The Chirp in CEBus has a spread spectrum bandwidth of 300 kHz in the existing power line communication, and the maximum expansion when the communication rate is 2400 b/s. Frequency gain.

GSM communication module. The link controller communicates with the management center computer by means of GSM short message. GSM has the characteristics of AlwaysOnline, no dialing, low price and wide coverage. It is especially suitable for applications that transmit small traffic data. It overcomes the limited communication range of general technology and high cost. And so on. The module supports 900/ 1800MHz dual frequency, sensitivity up to -0.22dB, frequency error less than 0.1, high connection rate, better signal quality, industrial grade design, ensuring unimpeded reception.

2.3 Segment Controller Software Framework The segment controller adopts the high performance, high reliability, 8kbytes Flash, 8-channel 10-bit A/D, and 8-bit single-chip microcomputer PIC16F877 with built-in watchdog. The strong and powerful is the whole road segment control. One of the important guarantees of reliability. The general flow chart of the software system is as shown. Its communication protocol is mainly embodied in the definition of communication frame format and related command parsing. The host computer sends a frame format to the link controller: a ballast node open distribution command frame; a unified switch command frame; a separate switch command frame; a ballast state query frame; an acknowledgement frame; an error frame. The data frame format sent by the link controller to the upper computer is: ballast node open request frame; status frame; acknowledgement frame; error frame. The frame format sent by the link controller to the power carrier communication (PLC) is: unified switch command; separate switch command; ballast status query frame; confirmation frame header effective length target address source address control word status information / y test and valid data K-like frame format 3 Conclusion The realization of networked real-time street lamp precise monitoring is the inevitable result of the development of digital technology, and is the inevitable direction of the development of urban street lamp management system. The networked real-time street lamp precise monitoring system involves the latest scientific research and technical research results in power electronics technology, power carrier technology, computer control technology, network communication technology and intelligent control theory and algorithm. It is an important symbol of urban modernization. . The adoption and promotion of the system not only improves the level of street lamp management and service quality, but also generates huge economic and social benefits in terms of energy conservation, environmental protection and social security.

1 Wang Wei, Zhang Weiqiang, Gao Guoan. Research on electronic ballast resonant load circuit. China Lighting Appliances, 2000(7): 15

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