Brazilian Nanotechnology National Laboratory,Giuseppe Máximo Scolfaro, 10000, Bairro Guará, , Campinas, São Paulo, Brazil.

Size: px

Start display at page:

Download "Brazilian Nanotechnology National Laboratory,Giuseppe Máximo Scolfaro, 10000, Bairro Guará, , Campinas, São Paulo, Brazil."

Avis Clarke
5 years ago
Views:

1 Key Engineering Materials Online: ISSN: , Vol. 605, pp doi: / Trans Tech Publications, Switzerland Energy Efficiency and System Control of Street Lighting Using Wireless Sensors Network and Actuators Felipe Lorenzo Della Lucia 1,2, a, Leandro Tiago Manera 1,b and Felipe Cassaro Frazatto 2,c 1 State University of Campinas, Department of Semiconductors Instrumentation and Photonics, Av. Albert Einstein, 400, DSIF, sala 202, Cidade Universitária, Campinas, SP - Brasil - Caixa-postal: Brazilian Nanotechnology National Laboratory,Giuseppe Máximo Scolfaro, 10000, Bairro Guará, , Campinas, São Paulo, Brazil. a fldlucia@yahoo.com.br, b manera@dsif.fee.unicamp.br, c felipe.frazatto@lnnano.cnpem.br Keywords: Sensors Networks, Energy efficiency, Mesh, HID, Street Lighting, Zigbee. Abstract. This paper presents the development and implementation of a wireless system for street lighting control and monitoring, focusing on its energy efficiency and reliability. Each node of the network consists of a lamp connected to an electronic dimmable ballast through a control unit and a radio module. The network is designed using the IEEE protocol and it is implemented using a mesh topology at 2.45 GHz. It is possible to adjust the power consumption and luminosity of each lamp at a particular point (or street) relative to traffic intensity or safety considerations, saving a considerable amount of energy. It is also possible to adjust the luminosity of the lamp according to the environment light by using a radiant sensor present in the control unit and check the lamp status (on or off). The entire network is monitored by self-proprietary software, and also includes the ability to make decisions depending on local sensors. Each node can also be used as a router to transmit the information from one node to another in order to extend the distance range the network can achieve. The main advantages of this system are the reduction of costs related to energy consumption and the ability to detect in a short time a lamp failure. Results show that it is possible to reduce the power consumption of a single lamp by 69%. The network range was adequate and each node itself could transmit and receive commands 130 m apart. Introduction Since the first attempt to use electric energy to illuminate the streets in replacement of wale oil and kerosene, constant effort has always existed to improve the characteristics of the public illumination system. The recent term Smart Grid is used referring to power grids which incorporate recent advances in communications and control to improve its characteristics. The public street lighting is, perhaps, the field within Smart Grid that offers the greater room for improvement, since it still uses very old and inefficient technologies. Data from the IEA (International Energy Agency) estimates that it is possible to save TWh per year if new technologies on lighting were implemented [1]. In view of this number, energy efficiency is a very important issue regarding public street lighting. When dealing with street lighting, several factors must be observed to achieve adequate operation: Uniformity, adequate glare and illuminance, visual comfort and reliability should always be considered when designing and operating the system. Besides, using the energy provided by power plants efficiently helps to reduce the amount of wasted energy due to losses and reduces significantly the amount of investments necessary both in the power generation and transmission system, benefitting the entire chain of the electrical system. One example of energy efficiency that has already been applied in the street lighting system is the replacement of old mercury vapor lamps by high pressure sodium lamps. Both lamps are High Intensity Discharge (HID), however the illumination efficiency of high pressure sodium (HPS) is higher, meaning that with the same lamp power it is possible to obtain a higher amount of lumens. All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications, (ID: , Pennsylvania State University, University Park, USA-13/05/16,01:33:34)

268 Materials and Applications for Sensors and Transducers III In this paper, a method of improving energy efficiency, illuminance, uniformity and reliability is proposed by controlling and

2 268 Materials and Applications for Sensors and Transducers III In this paper, a method of improving energy efficiency, illuminance, uniformity and reliability is proposed by controlling and monitoring the HPS lamps via wireless networks and actuators. With this network, it is possible to remotely control every lamp in a city or in a specific region. With the ability to dim the HPS lamps, it is also possible to control the luminosity of each lamp per street, relative to traffic usage and safety considerations, improving the energy efficiency of street lighting systems. The sensors installed in the control units are used to detect the light levels in situ and provide the ability to dim the lamps according its readings or it is also possible to adjust luminosity levels according to the hour of the day. Other kinds of sensors may also be installed in order to verify, for instance, air quality, humidity, etc. It is also possible to receive automatic remote notification in the event of a lamp failure, using the readings of a radiant sensor, alerting the system operator to replace the lamp, making the system more reliable. Other initiatives to control and monitor street lighting were previously reported using Power Line Communication (PLC), however, this technology has some drawbacks that may compromise the system reliability [1,2]. The price of PLC remote controllers is high and PLC usually suffers from impedance variations issues and high noise. When a short circuit appears, there is a lack of communication, since the network does not heal itself. The PLC technology seems not to have a focus on energy efficiency [1,2]. Other approaches have chosen DALI protocol to operate. This is a better approach than PLC, nevertheless it is required to use a pair of wires to form the bus for communication, being more indicated to be used indoors. One approach tried to merge wireless sensors networks and DALI protocol to control street lighting, however, the system required a microcontroller to decode the instructions from the wireless protocol DALI protocol and using a circuit to adjust the interface voltage levels (DALI uses 6.5V for low level and V for High level) [1]. Using GPRS networks is also possible, however it is necessary to pay the mobile network operators for using it (sometimes per message sent), making the cost prohibitive [3]. This paper proposes a different approach. It only uses RF communication modules and a control circuit, without the need of microcontrollers and adaptation circuits. The lamps chosen to be the object of study in this work were the HPS 150 W, since they are the one of the most common kind of lamps used on street lighting. Proposed System The system consists basically in nodes installed on each lamppost. Each node is constituted in 3 blocks: Communication and network module (CNM), control unit (CU) and power unit (PU). A control software is used to manage the entire network and system. Each block will be described in the following sections. Fig. 1 shows a picture of a node and network schematic. The total cost of the system was a constant concern in order to make it affordable and provide adequate rates of return. Fig.1. Node and Network Schematic.

Key Engineering Materials Vol. 605 269 Fig 2. Control Software Screen. Fig.3. (a) Active Power vs. Control Levels and (b) Illuminance vs. Distance from Lamp.

3 Key Engineering Materials Vol Fig 2. Control Software Screen. Fig.3. (a) Active Power vs. Control Levels and (b) Illuminance vs. Distance from Lamp. In order to build a network to connect each module that feeds and controls the lamps, it was chosen the protocol IEEE (Zigbee) to assemble the network (Zigbee is a self building network), since it was developed specifically to be used in sensors networks, providing ways to transmit relative small amounts of information between nodes at reduced energy consumption. The topologies chosen for this network were tree and mesh, since they provide ways to transmit and receive information using each element of the network as a router. This feature allows the network to use multiple hops and achieve higher range, as can be seen in Fig. 1. The biggest advantage of this topology is the self-healing property, in which, if one node of the network is broken, the information is sent through another path, using different nodes. On each node it is installed a communication module to perform the transmission and reception of the information. Each module operates at 2.4 GHz, transmitting signals with 50 mw power and has four analog inputs and 11 digital inputs/outputs (IO). The control unit is an electronic circuit connected to the I/O of the communication module and it is designed to actuate on the power unit. It is also responsible to collect the data from the radiant sensor and send it to the operator to inform about environmental conditions. Four control levels were implemented on the control unit, although more levels could be added if needed. It must be emphasized that no microcontroller is used, so that the cost of each node could be kept considerably low. The power unit consists on a ballast, responsible for igniting and sustaining the current on the lamp. Inductive ballasts are the most common and cheaper on the market, however, to improve energy efficiency and durability of the HPS lamps, an electronic ballast was adopted. The ballast chosen is designed to operate on 150 W HPS lamps with power factor of 0.98 and itself requires 14 W. The control unit is connected to its terminals to determine the dimming level.

4 270 Materials and Applications for Sensors and Transducers III The control software is self-proprietary Graphic User Interface (GUI) developed in C# and it is able to perform the interface between the operator and the network. The operator can check the status, set the dimming levels and read the sensors data of each node of the network. Fig. 2 shows the software control screen. Results and Discussion Fig. 3 (a) presents the power consumed by the system and the power factor as a function of 10 different levels of dimming. It is possible to reduce the power consumption of the system down to 31% of its nominal power. Despite of being possible to reduce the power, one should also check the power factor of the load. Since the power factor is optimized at the ballast nominal power, reducing the operation power also results in reducing the power factor. Each country has its own legislation regarding the minimum power factor. Typically it is used 0.92 as the limit one can operate; hence, the operator should only reduce the lamp power down to 36% of its nominal power. Another important parameter that must be observed while reducing the lamp power is the illuminance. Illuminance is the total luminous flux (visible) incident on a surface plane, per unit area. Illuminance unity in the SI is Lux lumens per square meter - and the majority of the legislations concerning illumination use it to define the requisites of illumination. The equipment used to measure illuminance is called luximeter. Fig. 3 (b) shows the measurement of the illuminance as a function of distance for different dimming control levels. The measurements were performed using Minipa MLM-1011 Luximeter all on the perpendicular plane relative to the lamp. One can observe that as the distance from the lamp increases, the illuminance value decreases, up to the point that no visible light reaches the luximeter. By checking the Brazilian legislation, the typical lamppost at a middle traffic condition ( cars per hour), the lamppost should be 8 m high and at least an average of 10 lux should reach the ground [4]. In this condition, it would be possible to dim the lamp down to 45% of its nominal power. It should be kept in mind that these considerations were made based on the measurement of only one lamp at once, without any influence of other lamps close to it, since the distance between lamps may vary according to the legislations, which usually take into account the traffic intensity and the height of the lampposts. In order to estimate the network range, experiments were conducted to determine how far it was possible to control the lamps and receive sensor data with the current communications modules. Results show that it was possible, with as single node, to control the lamp 130 m apart. This distance is very adequate, once the distance between lampposts is not usually higher than 40 m. When using 2 more nodes, each acting as a router, it was possible to receive sensor data and control the lamps 395 m apart, each node contributing to increase the network range at about 130 m. It can be done by taking three actions: Increasing the transmission power, using lower operation frequency (900 MHz, for instance), using antennas with higher gain on the communication modules. References [1] F.D. Perez, A.G. de Castro, J.M.F. Arias, F.J.B. Outeirino and A.M. Munoz: Low-rate wireless personal area networks applied to street lighting, Lighting Research and Technology 2013, Vol 45, p [2] R. Pantoni, D. Brandão: A confirmation-based geocast routing algorithm for street lighting systems, Computers and Electrical Engineering, Vol. 37 (2011), p [3] L. Long, C. Xiumin, W. Yong, W. Qing: The Development of Road Lighting Intelligent Control System Based on Wireless Network Control, International Conference on Eletrctronic Computer Technology, (2009), p [4] Norma Brasileira ABNT NBR 5101 Iluminação Pública Procedimento. 04/04/2012.

5 Materials and Applications for Sensors and Transducers III / Energy Efficiency and System Control of Street Lighting Using Wireless Sensors Network and Actuators /

A Monitoring and Control System for HID Lamps

A Monitoring and Control System for HID Lamps Abstract This paper will present the study and implementation of a control and supervision system for electronic ballast of high intensity discharge (HID)