**2. Specific aspects for the application in Brazil**

An application for public lighting involves some specific aspects that should be highlighted. Economic aspects and aspects of sustainability are relevant to a public lighting system. The current public lighting system in Brazil needs to be modernized and must rely on sustainable energy sources and energy rationing.

Moreover, by automating the lighting system, it is possible to provide the population with a better service in resolving problems. According to Elektro (2011), the concessionaire responsible for the public lighting has no means to obtain the information related to problems, such as a lighting point that is out of operation (either because of a problem with the lamp or the device). Currently, a public lighting failure is usually reported to the concessionaire by a customer complaining on the phone or at the concessionaire's web page, as indicated at the Cemig web site (ATENDIMENTO CEMIG, 2011). Another way to detect a problem is patrolling the structure, which is made without a defined logistic. For this reason, it is desirable that the system to be developed is able to report the status of the devices installed on public streets, and also provide emergency alarms.

This work aligns with the work that began in 2009 in the USA: a comprehensive program in which electricity distribution companies, device manufactures, telecommunication companies and Information Technology companies have joined the Department of Energy (DOE) and the National Institute of Standards and Technology (NIST, U.S. agency for standardization) to define standards for smart grids and assure interoperability for protocols and devices in various areas, such as telecommunications, Information Technology and energy. That work has produced a document (NIST, 2009), which contains a survey of more than 80 standards, including some directly related to this project: transmitting messages over wireless networks, using networks based on IP (Internet Protocol), ZigBee (ZIGBEE, 2007), using the standard specification of GPS signals (Global Positioning System) (GPS NAVSTAR, 1995) and W3C Simple Object Protocol (SOAP, Web Services standard).

Looking at the work developed in the U.S., in June 2010, the Brazilian government, through the Brazilian Electricity Regulatory Agency (ANEEL), opened a public hearing for strategic projects on the "Brazilian Smart Grid Program" (ANEEL, 2010a). This program focuses on presenting project proposals in order to join efforts to coordinate and generate new technological knowledge of great relevance for the Brazilian electricity sector. More specifically, in accordance with the document generated by the mentioned public hearing (ANEEL, 2010a), this study contributes to the research of "telecommunication infrastructure".

In addition, the regulatory resolution nº 414, of September 9, 2010 (ANEEL, 2010b) from ANEEL establishes changes to the maintenance policy for the Brazilian public lighting structure. This document states that, from September 2012, municipal governments shall be responsible for maintaining the public lighting structure, instead of the concessionaires, which shall be responsible only for power supplying.

Finally, control and monitoring public lighting, through lamps or dimming ballasts, decreases light pollution, caused by poor adjustment of luminosity and number of lamps lit in specific directions, depending on the angle, intensity, etc (Figure 1). Besides, light pollution should be studied aiming to improve roads, streets and avenues conditions, in order to provide better maneuverability for drivers, and brightness for unsafe places, such as alleys and public squares (MIZON, 2001) (SCHWARZ, 2003).

**Figure 1.** Light Pollution

338 Energy Efficiency – The Innovative Ways for Smart Energy, the Future Towards Modern Utilities

capture important information from diagnostics, operation and failures.

section, the conclusions are indicates the conclusions.

sustainable energy sources and energy rationing.

Services standard).

**2. Specific aspects for the application in Brazil** 

devices installed on public streets, and also provide emergency alarms.

This application consists of an urban network, where sensors (nodes) are coupled to the lamp posts or lighting points in order to control the control the lighting for these points, and

This type of application is expected to improve quality in public lighting service and rationalize power consumption through smart sensors and supervision screens. The next section describes specific aspects involving the quality of public lighting service and the current stage of its structure in Brazil. Section 3 describes the system requirements, which its understanding is fundamental to develop the control and monitoring application and routing protocols. In section 4 the solutions regarding the control and monitoring application are detailed. Section 5 is presented the routing protocols strategies. In the last

An application for public lighting involves some specific aspects that should be highlighted. Economic aspects and aspects of sustainability are relevant to a public lighting system. The current public lighting system in Brazil needs to be modernized and must rely on

Moreover, by automating the lighting system, it is possible to provide the population with a better service in resolving problems. According to Elektro (2011), the concessionaire responsible for the public lighting has no means to obtain the information related to problems, such as a lighting point that is out of operation (either because of a problem with the lamp or the device). Currently, a public lighting failure is usually reported to the concessionaire by a customer complaining on the phone or at the concessionaire's web page, as indicated at the Cemig web site (ATENDIMENTO CEMIG, 2011). Another way to detect a problem is patrolling the structure, which is made without a defined logistic. For this reason, it is desirable that the system to be developed is able to report the status of the

This work aligns with the work that began in 2009 in the USA: a comprehensive program in which electricity distribution companies, device manufactures, telecommunication companies and Information Technology companies have joined the Department of Energy (DOE) and the National Institute of Standards and Technology (NIST, U.S. agency for standardization) to define standards for smart grids and assure interoperability for protocols and devices in various areas, such as telecommunications, Information Technology and energy. That work has produced a document (NIST, 2009), which contains a survey of more than 80 standards, including some directly related to this project: transmitting messages over wireless networks, using networks based on IP (Internet Protocol), ZigBee (ZIGBEE, 2007), using the standard specification of GPS signals (Global Positioning System) (GPS NAVSTAR, 1995) and W3C Simple Object Protocol (SOAP, Web

Looking at the work developed in the U.S., in June 2010, the Brazilian government, through the Brazilian Electricity Regulatory Agency (ANEEL), opened a public hearing for strategic The current public lighting structure in Brazil consists of a set of lighting points arranged in a certain manner. Each point has a housing with a device called photocell relay, which is responsible for turning the lights on or off according to a brightness sensor. Then, at nightfall, the relay turns the light on at the lighting point. This limited structure may compromise consumption efficiency, quality of service to the community, and other factors, for example, problems in the lamp, power supply, the photocell relay, etc.

To solve the problems mentioned above in an automatic way, allowing fast and efficient preventive and corrective maintenance, an automation system may be applied. The basis for such a system is implementing the communication between parts involved, like devices,

computer software, among others. Therefore, the photocell relay mechanism can be attached to an Information Technology structure, through device and sensor networks, supervision workstations and applications.

Street Lighting System Based on Wireless Sensor Networks 341

development stage is restricted to alterations in the master part device, aiming to determine more appropriate, and also less vulnerable to transportation, means to perform maintenance on lighting points. Maintenance concerns handling from the field team, to make it practical to use. Furthermore, the project involves adapting the device to industrial production.

Closer to the project proposed in this work, which involves sensors communication in a system, the Smart Substation project from CPFL, in partnership with the Foundation for the Technological Development in Engineering (MUSP – FDTE) and CONTREL, proposes a smart system by adapting or inserting monitored devices with built-in intelligence in maintenance, security, qualimetry and control, connecting to the respective remote management centers. Nowadays, relays, sensors, qualimeters, and other digital devices operate underutilized, less integrated and do not repay their high costs. Back office processes (operation, planning, security, qualimetry, maintenance, etc.) are still detached

Information for this project was provided by Elektro and the Eldorado Institute, in order to modernize the infrastructure of public lighting through WSN communication and control and monitoring workstations, which allow rationing energy, sustainability, automated detection of physical or logical fails, alarms related to emergencies, supervision of lighting points, and controlling actions (turning the lamp on or off and adjusting brightness, for

The recent document proposed by IETF (RFC 5548, 2009), which describes requirements for routing on urban networks, also affirms that these networks must attend convergent traffic, where one node (usually a gateway or sink) receives messages from several low frequency meters (a maximum of one measurement per hour, and a minimum of one measurement per day). The number of nodes must be in the order of 102 to 107, distributed in areas varying from hundreds of meters to one square kilometer, considering that nodes are commissioned in groups, and the battery shelf life is usually in the order of 10 to 15 years. The frequency band must be ISM (Industrial, Scientific and Medical), and the nodes will probably have from 5 to 10 immediate neighbors to communicate. The routing protocol must enable the network to be autonomous and organize itself, requiring a minimum energetic cost for maintenance functions. The protocol must also ensure that any diagnostic or failure information from the nodes is communicated without interfering on the network

The project of a Wireless Sensor Network depends on the application where the network will be used, and it should be based on functional and non-functional requirements.

• Points supervision: node status, whether it is connected to the network or not; battery

• Control: switch on/off the luminosity level lamp; switch on/off a lamp post, a selected

power; lifetime estimation for battery and lamp; and LEDs luminosity level;

and without intelligence (PORTAL INOVAÇÃO CPFL, 2011c).

example) for lighting points.

**3. System requirements** 

operational mode, respecting the time limits.

Functional requirements for this type of project are:

segment, a street, neighborhood, city, etc;

The stage of development of public lighting projects in Brazil is restricted to rationing energy and improving lighting efficiency, by replacing sodium or mercury lamps by LED lamps, installing photovoltaic panels for sustainable lighting, powered by solar energy, and, finally, luminaires to reduce lighting focus dispersion (CPFL CAMPINAS, 2011).

LED lamps offer better color reproduction; they do not emit ultraviolet and infrared rays, they propagate less heat, and they attract fewer insects. They also show good efficiency and longer life, estimated at approximately 50,000 hours of operation. Sodium vapor lamps, most commonly used today, last up to 32,000 hours; mercury vapor lamps may last 12,000 hours, and metal halide lamps, commonly used in facades of buildings, 10,000 hours.

The Companhia Energética de Minas Gerais (Cemig), an electric energy utility company in the State of Minas Gerais, Brazil, together with the municipal government of Belo Horizonte, began testing LED lamps. Some luminaires have been already installed on poles near San Francisco Church (CEMIG, 2009). Cemig provides annual reports and sustainability reports that can be accesses at the company's website (CEMIG, 2011).

In addition, driven by the investments for the World Cup 2014, Cemig's project "Minas Solar 2014" seeks to install photovoltaic panels to power public lighting, aiming to improve public infrastructure and soccer stadiums (CHIARETTI, 2011).

Cemig signed a cooperation agreement with the U.S. government, through the U.S. Trade and Development Agency (USTDA), to fund their smart grid project. The U.S. agency will provide US\$ 710,000 for the Brazilian company, to be applied on the study that analyzes the feasibility of implementing smart grids, which has been developed by the company together with Light (SMART ENERGY ONLINE, 2011).

CPFL Energia, an electric energy utility company in Brazil, together with the Development Foundation from the University of Campinas (FUNCAMP), the Foundation for Research and Advisory Service to the Industry from the Federal University of Itajubá (UNIFEI), HYTRON Hydrogen technology, FUSION, and the AQUA GENESIS Institute for Studies and Projects on Energy, Hydrogen and Environment, is currently investing in a project of a solar photovoltaic and/or wind hybrid system to generate electricity, which can operate connected to the distribution network or isolated, and the goal is to evaluate the integration of distributed generation at low voltage, with and without energy storage. Considering the increasing use of local alternative sources of energy generation, low power systems, renewable energy sources, and technological availability that allow immediate applications, utilization of solar photovoltaic and wind energy, with and without energy storage, stands out above other options (PORTAL INOVAÇÃO CPFL, 2011a).

A project that involves communication, however not between sensors (PORTAL DE INOVAÇÃO CPFL, 2011b), called "failure diagnostic system for public lighting points", is being developed by CPFL in partnership with companies MATRIX and PLAYMUSIC. The development stage is restricted to alterations in the master part device, aiming to determine more appropriate, and also less vulnerable to transportation, means to perform maintenance on lighting points. Maintenance concerns handling from the field team, to make it practical to use. Furthermore, the project involves adapting the device to industrial production.

Closer to the project proposed in this work, which involves sensors communication in a system, the Smart Substation project from CPFL, in partnership with the Foundation for the Technological Development in Engineering (MUSP – FDTE) and CONTREL, proposes a smart system by adapting or inserting monitored devices with built-in intelligence in maintenance, security, qualimetry and control, connecting to the respective remote management centers. Nowadays, relays, sensors, qualimeters, and other digital devices operate underutilized, less integrated and do not repay their high costs. Back office processes (operation, planning, security, qualimetry, maintenance, etc.) are still detached and without intelligence (PORTAL INOVAÇÃO CPFL, 2011c).

Information for this project was provided by Elektro and the Eldorado Institute, in order to modernize the infrastructure of public lighting through WSN communication and control and monitoring workstations, which allow rationing energy, sustainability, automated detection of physical or logical fails, alarms related to emergencies, supervision of lighting points, and controlling actions (turning the lamp on or off and adjusting brightness, for example) for lighting points.
