Nowadays energy crisis in India is a critical issue. Enormous electric energy is consumed by the street lights. At present, street lights a r e controlled manually and it leads to energy loss. In the present study smart street lighting system manages the street lights automatically turn on in the evening, lighting the road for few hours. It gradually reduces the brightness when no one is detected in that area. When vehicles or pedestrians are detected, the street lights automatically turn on. Design of smart Street lighting system does not only achieve energy-saving but also extend the service life of street light equipment.

1. Proceedings of the 2nd
International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
44
SMART STREET LIGHTING SYSTEM BASED ON SENSORS USING
PLC AND SCADA
Swathi C A1
, Hemanth Kumar S1
, Annappa A R2
1
(Mechanical Dept, VTURC/ VTU, Mysore, India)
1
(EEE Dept, V.V.I.E.T/ VTU, Mysore, India)
2
(Mechanical Dept, VTURC/ VTU, Mysore, India)
ABSTRACT
Nowadays energy crisis in India is a critical issue. Enormous electric energy is consumed by the street lights. At
present, street lights a r e controlled manually and it leads to energy loss. In the present study smart street lighting
system manages the street lights automatically turn on in the evening, lighting the road for few hours. It gradually
reduces the brightness when no one is detected in that area. When vehicles or pedestrians are detected, the street lights
automatically turn on. Design of smart Street lighting system does not only achieve energy-saving but also extend the
service life of street light equipment.
Keywords: LED (Light Emitting Diode), PLC (Programmable Logical Controller), Sensors.
1. INTRODUCTION
The electricity sector in India had an installed capacity of 237.742 GW, the world’s fourth largest. The total
annual generation of electricity from all types of sources was 1053.9 Tera Watt-hours (TWH). Nowadays in the whole
world, street lights consume enormous electric energy. The Bureau of Energy Efficiency, based on Central Electricity
Authority statistics, has estimated gross energy consumption for public lighting to be 6,131 million kWh in India.
Providing street lighting is one of the most important responsibilities of a city. Lighting can account for 10 – 38% of the
total energy bill in typical cities worldwide. Inefficient lighting wastes significant financial resources each year. There
are a small number of streets in the town and the city before, street lamps and management control is relatively simple.
But as the country gradually come into a well-off society and with development of urbanization the number of streets in
the town increase rapidly. So the control and management of street lighting become problems. Energy efficient
technologies and design can cut street lighting costs dramatically (often by 25-60%); these savings can eliminate or
reduce the need for new generating plants.
At present, street lighting control at most of the places is only by manual control, a control switch set in each of
the street lights, it is the so-called first generation of the original street light control, which is inefficient and a waste of
manpower, and cumbersome to operate street light opening and closing time. Or using optical-control method, set up
optical control circuit, changes the resistance by using of light-sensitive device to control street lights. Which light up
automatically in the evening after dark, turn off automatically after dawn in the morning, but the low reliability of the
method, vulnerable to interference, night street lighting is too bright and is a waste of energy and other issues [1]. The
other is time-control method (that is, from time to time opening and closing control) [2], and time-optical-control [3]
(that is, from time to time with light intensity control). This three street light control method can be attributed to the
second generation of street light control. The second generation street light control method achieved automatic control of
street light. Thereby reducing the labour intensity and lowering labour costs and improving the efficiency of street
INTERNATIONAL JOURNAL OF MECHANICAL ENGINEERING
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2. Proceedings of the 2nd
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17 – 19, July 2014, Mysore, Karnataka, India
45
lighting control. But it also exposed a problem that it cannot meet the needs of the growing street light information and
intelligent management. The time of lighting is not only lack of precision, many street lights are controlled by using the
mid-night lights strategy, energy-saving effect is poor. In short the current street lighting strategy is simple and crude,
lack of humane care of the car and human, cannot achieve the sleep and wake-up call of the lamps in time. An urgent
need to develop a high degree of information, to facilitate the realization of network-based, highly intelligent automatic
control system of street lighting, which is the third generation of intelligent street light control systems.
There are some attempts in which the energy wastes of the street lights are reduced. A sensor light, which is
controlled by a brightness sensor and a motion sensor, is sometimes used to reduce loss of energy [6]. It only turns on for
while when the motion is detected in front of the sensor and when it is dark. Ideally, it is desirable that smart street lights
look like usual street lights; no one notices that smart streetlights are usual street lights. Smart street lights have turned on
whenever anyone notices them. Smart street lights have been researched by many researchers. In [5], smart street lights
that cooperate with each other to shine a light on pedestrians are proposed. This kind of smart streetlights exchange
information of detecting moving objects and turn on so that neighbourhood of the moving objects lightens. In [7], the
method of pedestrian tracking is proposed for smart street light systems. Detection of existence of pedestrians or vehicles
is important for smart street light systems. In [8], image processing is used to decrease electric power of street lights; the
method proposed in [8] obtains the pictures of street lights at night by security cameras and adjusts brightness of street
lights by the pictures. In [4], photovoltaic panels are attached to smart street lights to save energy. This research revises
street lights themselves but does not focus on smart street light systems. There are many researches of smart streetlights
but few researches focus on smart street light system that behaves looking like usual street lights based on sensor
networks. Centralization process control combined with increased mechanization has resulted in improved productivity
[4]. Nowadays advanced control systems like PLCs are extensively used in industries.
2. PROPOSED SYSTEM
The features of the smart street lights are as follows
2.1 Low Cost
The aim of smart street lights is to save energy and to save cost. Smart street lights whose cost is more than the
cost of energy that is saved by the smart street lights do not become widely used. Thus, the smart street lights in [9] use
only the parts of mass production to keep the cost of smart street lights as low as possible.
2.2 No Difference from Usual Lights
Whenever pedestrians or a driver of vehicles sees lights, the lights have already turned on. Pedestrians or drivers
do not notice that lights turn off or that the lights that they see are smart street lights.
2.3 Safety
Usual smart street lights do not always turn on and therefore public safety may get worse. The aim of the smart
street lights in [9] is to keep public safety and to save energy. Therefore, street lights whose areas are within the views of
the pedestrians or vehicles must turn on and street lights that are related with safety of the pedestrians or vehicles must
also turn on.
Smart street lighting includes a total system with dimmable luminaries, advanced lighting control solutions, and
communication systems. The solution focuses on low energy consumption and high functional standard. It also in most
contexts automatically declines the maintenance costs for the operator in combination with increased safety for the street
user.
Over the last years new technology has been developed and implemented in multiple systems that can help to
save even more energy.
Networking and automation technology allows for the adjustment of light levels to the exact need to keep the
roads safe based on weather conditions, traffic density and other external factors. LED lighting also has great potential to
save energy in outdoor lighting. In this paper taking the entire above mentioned criterion into account, a PLC is proposed
for the automatic street lighting control system.
3. COMPONENTS OF PROPOSED SYSTEM
3.1 Programmable Logic Controller
It is usually located in the field close to the processing unit. PLCs are small and operator interface may be
simple as button switch. The block diagram of PLC system is as shown in the Fig.1.

3. Proceedings of the 2nd
International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
46
Fig. 1: Block Diagram of PLC System
The basic components in a PLC system are sensing section, Input module, Controller, Programmer, Output
module and Field hardware devices. Most PLCs have the ability to communicate with other devices. These devices
include computers running programming software or collecting data about the manufacturing process, a terminal that lets
an operator enter commands into the PLC, or I/O that is located in a remote location from the PLC. The PLC will
communicate to the other devices through a network interface.
The controller offers two programming languages such as:
3.1.1 Ladder language (LD)
The most popular language used to program a PLC is ladder logic. Ladder Language is a graphic Language. It
can be used to transcribe relay diagrams, and is suited to combinational processing. It provides basic graphic symbols
such as contacts, coils, and blocks. Specific calculations can be executed within the operation blocks.
3.1.2 Function block diagram language (FBD)
FBD mode allows graphic programming based on the use of predefined function blocks. It offers a large range
of basic functions such as timer, counter, logic, etc.
In the present work, a Delta PLC is used to control the street lighting system. The software used is WPL soft
version 2.33 and it has 8 digital inputs and 6 digital outputs. Every PLC has associated programming software that allows
the user to enter a program into the PLC. The Delta PLC is as shown in the Fig. 2.
Fig. 2: Delta PLC
3.2 Supervisory Control And Data Acquisition
SCADA is an acronym that denotes Supervisory Control And Data Acquisition. SCADA is a control system
with applications in managing large scale, automated industrial operations. In industries to control any distributed
machine or process, there is a requirement to see and control from a central place. This can be solved using SCADA
system. Thus we can get all the readings of process parameters which are in distributed condition on the screen. We can
give control commands to process through PLC or through some other controlling device if it is available. SCADA is
known as Man Machine Interface (MMI). The block diagram of SCADA system is as shown in the Fig.3.

4. Proceedings of the 2nd
International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
47
Fig. 3: Block Diagram of SCADA System
In the present work Proficy iFIX SCADA is used to control and monitor the smart street lighting system. Proficy
iFIX instantly collects and delivers critical information to the desktops of operators, supervisors and managers
throughout the organization, and presents the data in the graphical format that are easy to understand.
3.3 Lamp Unit
The LED Street light is an integrated light-emitting diode (LED) light fixture that is used for street light. An
LED street light is an integrated light that uses light emitting diodes as its light source. These are considered integrated
lights because in most cases, the luminaries and the fixture are not separate parts. New in manufacturing, the LED light
cluster is sealed on a panel and then assembled to the LED panel with a heat sink to become an integrated lighting
fixture.
The lifespan of an LED street light is determined by its light output compared to its original design
specification. Once its brightness decreases by 30 percent, an LED street light is considered to be at the end of its life.
3.3.1 Advantages of LED Street Lights
• Low energy consumption: The much lower energy usage of LED lighting can dramatically reduce
operating costs.
• Long and predictable lifetime: The lifetime of LED street lights is usually 10 to 15 years.
• Quick turn on and off: Unlike fluorescent lamps, which take time to heat up once switched on, LEDs come
on with full brightness instantly.
3.4 Sensor Unit
It consists of the infrared sensor. It sends out the message to other units under the condition that motion is
detected. This unit is placed at many locations like electric poles, house gates and inside or outside of the door, to ensure
that every street light turns on before pedestrians or a driver of vehicles notice the lights. An infrared sensor is an
electronic instrument that is used to sense certain characteristics of its surroundings by either emitting or detecting
infrared radiation. It is also capable of measuring heat of an object and detecting motion. Key benefits of infrared sensors
include low power requirements, simple circuitry, and their portable feature.
Here we use a Passive Infrared (PIR) motion detector used to control an outdoor, automatic light. A PIR-based
motion detector is used to sense movement of people, animals, or other objects.
3.4.1 Operating principles
All objects with a temperature above absolute zero emit heat energy in the form of radiation. Usually this
radiation is invisible to the human eye because it radiates at infrared wavelengths, but it can be detected by electronic
devices designed for such a purpose.
The term passive in this instance refers to the fact that PIR devices do not generate or radiate any energy for
detection purposes. They work entirely by detecting the energy given off by other objects. It is important to note that PIR
sensors do not detect or measure "heat"; instead they detect the Infrared radiation emitted from an object which is
different from but often associated/correlated with the objects temperature.

5. Proceedings of the 2nd
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17 – 19, July 2014, Mysore, Karnataka, India
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4. METHODOLOGY
The block diagram for the smart street lighting system is as shown in the Fig.4.
Fig. 4: Block Diagram for the Smart Street Lighting System
The smart street lights require sensor networks. In this paper infrared sensors are used for sensor networks.
These sensors will sense the presence of vehicle or pedestrians, so this will be the input to the sensors. The output of the
sensors will be interfaced to the PLC through the relay circuit i.e. the sensor output will be given to the base of the
transistor and the emitter of transistor to the relay, the relay is connected with a freewheeling diode. It is used to
discharge the current in the loop itself without affecting the circuit when supply is off. The output of the relay circuit is
given as input to the PLC. A PLC executes an initialization step when placed in run mode, and then repeatedly executes a
scan cycle sequence.
The basic PLC scan cycle consists of three steps an input scan, a user program scan, an output scan. The total
time for one complete program scan is a function of processor speed, I/O modules used, and length of user program.
Typically, hundreds of complete scans can take place in 1 second. The PLC is interfaced to the lamp unit through the
relay circuit i.e. the relay and freewheeling diode. Based on the signal from sensor the PLC gives the signal to relay
circuit and the relay which is normally closed will get energized and become close contact and makes the circuit which in
turns gives the signal to lamp units, the street lights will ON after some seconds the lights will go OFF. Depending on the
speed of the vehicle or pedestrians the number of street lights will ON and goes OFF after some seconds.
The lightings of roads are approximately 12 hours from about 6:00 PM to 6:00 AM. The maximum load demand
occurs during 7:00 PM to 11:00 PM, so after 11:00 PM to 6:00 AM the street light will work as smart street lights. The
monitoring and control of the smart street light can be achieved by using SCADA, it can be placed in the substation and
they can visually see the working of smart street light, whether its working condition is good or not sitting at the control
place. The combination of an infrared sensor and a PLC will act as an intelligent mechanism for ON-OFF switch.
Switching the light ON and OFF is automatic and will require no human intervention; it is based on the intensity of
ambient light. This will ease of tension of switching ON the lights as the intensity of natural light falls in the evenings
and switching OFF the same in the mornings. This automation not only obviates the need of manpower for its operation
but also nullifies the risk of wastage of stored power which otherwise may occur due to early switching ON or late
switching OFF by manual operation.
5. PRIMARY FEASIBILITY STUDY
A case study of replacing 1000 High Pressure Sodium (HPS) street lights by LED lights with smart street light:
Let us assume 1000 HPS lamps of 400w, working from 6p.m to 6a.m.
Losses in the choke coil = 20w (average/1hps bulb).

6. Proceedings of the 2nd
International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
49
Let us assume for 1 unit it cost 5 Rs.
5.1 Replacement by LED
Total power consumed by 1 LED = 200w.
(Here we are going to consider 6 hours because we are using Smart Street light. From 7p.m to 11p.m it will
work like Normal Street light i.e., continuously operate for 4hour and for the remaining time it works as Smart Street
light depending on vehicle movement it will be on so let us assume that as 2 hours so total 6 hours).
5.2 Investment Cost
Cost of 1 LED system = 10,800 Rs.
Cost of PLC = 1,00,000 Rs.
Cost of SCADA = 1,00,000 Rs.
Cost of 1 PIR sensor = 600 Rs.

7. Proceedings of the 2nd
International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
50
Investment = 1,16,00,000 Rs
6. CONCLUSION
In this paper an approach for controlling street light system using PLC and SCADA is proposed. The proposed
controller gives fast, reliable and power efficient street light switching. It also helps to reduce power consumption. The
smart street lights look like a normal street lights, and the street lights will turn on before anyone sees them so that no
one notices this street lights as Smart Street Lights. This paper confirms that the proposed Smart Street Lighting system
based on sensors using PLC and SCADA has great potential to revolutionize street lighting system and in turn saves large
amount of energy.
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