computerized expert system for lighting grids

Computerized Expert System for Lighting Grids

COSTIN CEPISCA

Faculty of Electrical Engineering

Politehnica University of Bucharest

Splaiul Independentei 313, s.6, Bucharest

ROMANIA

[email protected] http://www.electro.pub.ro

HORIA ANDREI


University Valahia of Targoviste

ROMANIA

[email protected]

SORIN DAN GRIGORESCU


Politehnica University of Bucharest

ROMANIA

[email protected]

MIRCEA PERPELEA

University of Pitesti

ROMANIA

[email protected]

LAURENTIU STANCU

Amiras C&L Impex SRL Targoviste

ROMANIA

[email protected]

VALENTIN DOGARU ULIERU


University Valahia of Targoviste

ROMANIA

[email protected]

Abstract: - An important equipment of a lighting system is the switch on point, which ensures the correct supply of

the lamps on an hour interval imposed by the beneficiary and thus also provides the energy economy. The paper

proposes an expert system which uses the programmable automat ALPHA XL and which leads an automat system for

switch on points in public lighting systems. It is presented the hardware and software implemented application and

the performances analysis of the proposed system.

Key-Words: - lighting system, switch point, expert system, programmable automat.

1 Introduction The present switches on points of lighting grids have no

automated systems, starting to function and

disconnecting, most often, at the manual action [1]-[5].

The new intelligent equipments presented in this paper,

to increase the efficiency of the public lighting [6]-[9],

include more functions: switch on/off depending on the

local lighting state; the possibility of switch on/off

Proceedings of the 7th WSEAS International Conference on CIRCUITS, SYSTEMS, ELECTRONICS, CONTROL and SIGNAL PROCESSING (CSECS'08)

ISSN: 1790-5117 133 ISBN: 978-960-474-035-2

depending on the functioning preliminary schedule; the

knowledge from distance of the functioning state of the

respective electric network, the signaling at the

appearance of some possible defects; the possibility of

remote controlling the switch on/off commands; the

knowledge possibility from a central point of the

energetic consumptions in each switch on point and the

state of the respective network, especially that the

measured quantities are most often non-sinusoidal; the

possibility of establishing economic functioning regimes,

inclusive at voltages lower than nominal voltages; the

endowment with a distance transmitting device of the

command and measuring information: radio, wireless etc.

These new functions can be implemented using

hardware and software specialized elements, such as

programmable automats ALPHA XL. The programmable

automat (PLC) is a device which allows the control and

the automation of the working regimes of several

electrical equipments. The PLC receives signals through

the agency of its inputs, processes them after an

established program and transmits signals to its outputs.

The specialized program is realized with a

programming soft. Through the program, we can

command the inputs and outputs as we wish; we can

measure times and perform calculus operations. The

main characteristics of a PLC are: the maximum number

of inputs/outputs, the memory capacity and the calculus

speed. The compact programmable automats are defined

through the next system characteristics:

• programming with the same software package,

regardless of the number of inputs/outputs;

• possibilities of local and distant extension;

• integrated interface for communication;

• removable terminal blocks, with screws;

• compact gauge.

Through the agency of the menu and only with the help

of the buttons on the apparatus, the command scheme

can be introduced directly as a scheme of connections

with contacts and relay coils. The introduction can be

alternatively made using ALPHA XL and a PC. On the

MFD screen or on the PC, the active states from the

command scheme can be immediately observed and thus

precious time is saved.

2 Using the PLC to control the lighting

systems Regarding the use of this programmable automat for the

lighting control, we can make the following

appreciations:

- the lighting switch on/off are possible in the

centralized or decentralized variant;

- the lighting switch on and switch off are possible in the

centralized or decentralized variant through the impulse

relay function;

- the lighting switch off command can be realized through

the agency of the clock delay, which facilitates the

centralized disconnection of the lighting and the energy

economy;

- a base device can control up to 12 independent lighting

groups. Special commands for lighting can be realized,

such as centralized lighting for maintenance activities and

automatic commutation for reduced lighting;

- the montage of these devices in the plug board charts

for the modular equipment is facilitated by the 45 mm

frontal dimension and the width which is 4,6,8 and 12

multiplied with the modular step.

Fig.1. Programmable automat ALPHA XL

In figure 1 is presented the configuration of this device,

chosen to equip the switch on point. Among the technical

characteristics which make it useful in our application we

name:

- applications in the domain between discreet components

and systems with PLCs;

- models with d.c. 24Vcc supply or a.c. 100-240Vac;

- software resources even for complex applications;

strong set of predefined functions, including PID, SPD,

PWM, mathematic calculus;

- 10-24 I/O, extension possibility with digital or

analogical modules, thermo element signal adaptors;

- for the models with d.c. supply the first 8 inputs can be

used also as analogical inputs in the range 0…10 V with

a resolution of 9 bits / 500 values in the measuring range;

- memory for maximum 200 block functions.

ALPHA XL combines all the advantages of a PLC

system in a very compact casing and ensures a reduction

of the cost price regarding the occupied surface, the

relays and the contactors. Up to 64 functions can be

processed by a program.


ISSN: 1790-5117 134 ISBN: 978-960-474-035-2

Each of the valid functions (time, numerator, analog

processing converter, calendar/clock, etc.) can be used in

all of the programs, every time when needed. ALPHA

XL includes a tripling of the program capacity up to 200

functions and a big screen, extension options and a

second communication block, 15 new functions suited to

the instruction set, including mathematical operations,

PWM and SMS messages functions. The easy operating

and the legible screen are two big advantages of ALPHA

XL, offering in the same time graphics from the moving

bar and text on screen. The three levels of password

protection prevent unauthorized access to the processed

parameters and data, which can be changed directly

through 8 key functions.

ALPHA XL is equipped with a communication

interface and with the possibility of ensuring an

automatic control through a GSM modem. Additionally,

it’s possible to send SMS texts to a mobile phone, e-mail

to a PC or fax. The extended analogical modules increase

the applications level. With these modules it’s possible to

generate voltage or current signals and to measure

temperature. The I/O points of the slave devices are

electronically recorded through the bus connection or the

PLC program introducing the master into the network.

All the controllers from the ALPHA series can be

programmed with the soft MS Windows AL PCS/WIN.

This software is very easy to use and doesn’t need the

user to have experience. The programming of ALPHA is

easy and is made placing the different elements of the

program into a graphic programming environment.

3 Hardware and software configuration

of PLC for controlling the switch on

point of public lighting systems To configure the programmable automat ALPHA XL for

the application related to the control of switch on points

in public lighting, [10], we take into account the next

requirements:

- Connecting the automat consumer, depending on the

lighting state, through the agency of a solar radiation

transducer or through manual command;

- Connecting the lighting network using an hour program,

depending on the day from the week;

- Supplying the network through the agency of voltage/

frequency converter;

- Supplying the lighting through the agency of an

autotransformer, in order decrease the lighting intensity

between certain hours (the reduction of the luminous

flux);

- Disconnecting the lighting in situations commanded by

the Civil Protection and the predefined command of an

alarming siren (with a certain sound clock);

- Disconnecting the lighting in function of the arisen

failures (over and sub voltage, over and sub current), to

identify the abnormal working of the installation (bus

interruptions, energy thieveries);

- Protection sensitizing depending on the chosen supply

variants: directly, converter, autotransformer;

- Metering the consumed energy (meter of impulses taken

from an administration system);

- Supervising the temperature and sending this value at the

control point (with the help of a temperature transducer).

Fig.2. Programming scheme.

3.1 Inputs and outputs assignations

The assignation of the inputs and the outputs are presented

below.

� Inputs:

I01 – Automation supply switch (network operating) –

digital, I02 - Luminous intensity transducer (0-10 V)-

analogical, I03- Automatic functioning switch depending

on digital light sensor, I04 – Automation functioning

switch depending on programming clock – digital, I05 –

Civil Alarm signal input – digital, I06 - Current

transducer signal input – (0-10V) analogical, I07-Voltage

transducer signal input (0-10V) analogical, I08-

Temperature transducer signal input (0-10V)-analogical,


ISSN: 1790-5117 135 ISBN: 978-960-474-035-2

I09- Energy meter signal input (0-10V) - digital, I10-

Automation functioning switch with frequency

converter– digital, I11-Automation– digital.

� Outputs:

O01- Temperature (0-10V) –analogical, O02- Lighting

command – digital, O04 – Civil defense siren – digital,

O05 – Autotransformer servomotor – digital, O06-

Converter command ( 0-10 V) – analogical, O07– Output

for impulses proportional with consumed energy –

digital, O08 – Cabin fan command – digital.

The programming scheme and the utilization interface

are presented in figure 2, respectively in figure 3.

Fig.3. Utilization interface.

3.2 Program work algorithm

The input functions I01, I02, and I03 give the general

validation conditions for the lighting command O 02.[11]

The input analogical signal, received from the

twilight transducer is compared with the values imposed

in the lighting controller B 15 and B 16. Depending on

this comparison the automat will decide if it’s the

moment to command the connection of the public

lighting.

The system state is visualized on the display screen B 17

and B 20 (B 17 indicates the “lighting turned on” state

and B 20 indicates the “lighting turned off” state). The

two displays are conditioned by the Boolean function B

18, like in figure 4.

Fig. 4. The system state.

The “Disconnect” function is activated through the

application of a digital system at the I05 input. In this

state, the automat commands the public lighting

disconnection (if the conditions were fulfilled). The digital

signal enters in the loop B 25, conditioning depending on

the command key), B 26 (signal negation), generating a

signal in B 28 (“and” logic), disconnecting the lighting

contactor. The display is presented in figure 5.

Fig. 5. The display is activated.

The supervising of the failures (voltage and current) is

made with the functional blocks B32 and B33 which take

over the analogical information from the inputs I06 and

I07 through the agency of B31 and B32. These states are

shown in figure 6, respectively in figure 7.

Fig. 6. The functional blocks B32 and B33.


ISSN: 1790-5117 136 ISBN: 978-960-474-035-2

Fig. 7. The functional blocks B31.

The visualization of the voltage and current protection

state is made through the optic blocks B 31 and B 32, is

show in figure 8.

Fig. 8. The integrated signal of voltage and current.

Depending on the chosen automation variant: through the

autotransformer or through the converter, the current and

voltage protections automatically modify their working

parameters.

The failure, figure 9, is shown on the B 23 display. When

the converter works, the input signals integrate in blocks

B06 and B07, through the agency of the amplifiers B04

and B05. The resulted signal integrates in blocks B 08

and B 09. The failure is shown on the B 22 display. The

failure signals are totalized through the “OR” logic in the

functional block B10 - figure 10. When the

autotransformer works, the input signals integrate in the

B12 and B13 blocks, through the agency of the

amplifiers B64 and B11. The resulted signal integrates in

blocks B19 and B21.

The automation working in the autotransformer variant is

realized when at the I11 input a digital signal is applied,

signal which is also found at the terminals of B 02.

The autotransformer is operated by the digital output O

05, commanded by the B 02 “AND” block. The working

takes place when all the three signals are simultaneously

applied from I 11, I 01 and the programming clock B 03.

With the help of this clock we can program the period in

which the luminous intensity will reduce (between what

hours and what days), shown in figure 11.

Fig. 9. The failure.

Fig. 10. The functional blocks B10.

Fig. 11 The set of time switch.

The automation functioning with the help of the

frequency converter is realized when at the I 10 input

a digital signal is applied and when the system is in

operating state (I01 is supplied). The signal from I10

is applied to the integrator blocks B52 and B55

which also take over the analogical information from


ISSN: 1790-5117 137 ISBN: 978-960-474-035-2

the I02 input. The system state is visualized on the

B56 display, figure 12.

Fig.12. The functional blocks B56.

4 CONCLUSIONS From the electrical energy consumer categories, with an

important weight, circa 10% is owned by the public

lighting. An important equipment of a lighting system is

the switch on point, which ensures the correct supply of

the lamps on an hour interval imposed by the beneficiary

and thus also provides the energy economy.

The new intelligent equipments used in this paper to

increase the efficiency of the public lighting must include

more functions: switch on/off depending on the local

lighting state; the possibility of switch on/off depending

on the functioning preliminary schedule; the knowledge

from distance of the functioning state of the respective

electric network, the signaling at the appearance of some

possible defects; the possibility of remote controlling the

switch on/off commands; the knowledge possibility from

a central point of the energetic consumptions in each

switch on point and the state of the respective network,

especially that the measured quantities are most often

non-sinusoidal; the possibility of establishing economic

functioning regimes, inclusive at voltages lower than

nominal voltages; the endowment with a distance

transmitting device of the command and measuring

information: radio, wireless etc.

These new functions can be implemented using hardware

and software specialized elements, such as

programmable automats ALPHA XL.

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ISSN: 1790-5117 138 ISBN: 978-960-474-035-2

computerized expert system for lighting grids

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