**5. Experimental results**

In order to communicate to the power quality monitoring hardware, application software is created to display and to plot the waveform. The application software connects to the monitoring hardware via the Ethernet network. It both gets the display information and saves the fault data to PC or laptop. It also shows the fault waveforms on the PC or laptop screen. The communication procedure connecting between a monitoring hardware to PC or laptop is to get the necessary information which is executed in the following steps:


When the connection procedures have been already established between the hardware and the computer in consequence, the user can monitor the voltage, the frequency and the fault in power lines on the PC or laptop screen from the remote site. Additionally, the user can also open the data file which is saved in the computer.

the data under the considerable analysis of the cause in the faults at later time. The

In order to communicate to the power quality monitoring hardware, application software is created to display and to plot the waveform. The application software connects to the monitoring hardware via the Ethernet network. It both gets the display information and saves the fault data to PC or laptop. It also shows the fault waveforms on the PC or laptop screen. The communication procedure connecting between a monitoring hardware to PC or

1. A user sends a request signal with the application program to the power quality

2. The power quality monitoring hardware receives the request signal and establishes the

3. The power quality monitoring hardware sends the information to PC or laptop for

4. If any fault occurs, the fault data will be saved into the PC or laptop storage in the

5. A user can take the application software to display the fault waveform for investigating

When the connection procedures have been already established between the hardware and the computer in consequence, the user can monitor the voltage, the frequency and the fault in power lines on the PC or laptop screen from the remote site. Additionally, the user can

the problem in power lines from the saving path above.

also open the data file which is saved in the computer.

laptop is to get the necessary information which is executed in the following steps:

developed application software is shown in Fig. 14.

Fig. 14. Application software for waveform display

**5. Experimental results**

monitoring hardware.

displaying.

specific path.

connection to PC or laptop.

Fig. 15. (a) Voltage sags on phase A,B and C, (b) Voltage sag on phase A, (c) voltage sag on phase B and (d) voltage sag on phase C

For more advantage, the communication of the power quality monitoring hardware and PC or laptop is not only limited with the only one hardware but also connected to other hard-

A Power Quality Monitoring System

**6. Conclusion and future work**

signals in each phase.

needed.

**7. Acknowledgements** 

**8. References**

Via the Ethernet Network Based on the Embedded System 247

Fig. 15(a) is the picture of sags for all 3 phases. The experimental results appeared in Fig. 15(b), (c) and (d) are the examples of sag in phase A, B and C chronically from Fig. 15(a). It is

Fig.16 is the zoomed picture from Fig. 15(a) to show the detail characteristics of the fault

Another experiment of this chapter is applied to detect the fault on a single phase system.

A power quality monitoring system via the Ethernet network based on the embedded system has been proposed in this chapter in order to monitor the power quality in case of faults detection and also to measure voltage and frequency in power lines. ADUC7024 and LPC2368 of ARM7 microcontroller are selected to apply in the power quality monitoring system for not only detecting the fault signals that cause any problems in either the system or the end user equipment but also reading and writing them in real time of power fluctuation. Moreover, the fault signal data can be sent and stored in SD-CARD to display later on the screen of PC or laptop at the site place. However, the users can download and analyze the fault signal data which have already sent and stored in SD-CARD via the Ethernet network using TCP/IP and UPD protocol at some other time when of necessity

For future work, the researchers tend to substitute ARM7 with ARM9 in order to monitor power quality and to detect the transient in power lines. In any case, the researchers have

The authors gratefully acknowledge to National Science and Technology Development Agency (NSTDA), Ministry of Science and Technology of Thailand, Thailand Research Fund

Auler, L.F. & d'Amore, R. (2003). Power Quality Monitoring and Control using Ethernet

Baggini, A. B. (2008). *Handbook of POWER QUALITY*, WILEY, ISBN 978-0-470-06561-7,

Batista, J.; Alfonso, J.L. & Martins, J.S. (2004). Low-Cost Power Quality Monitor based on a

Dugan, R.C.; McGranaha, M.F.; Santoso, S. & Beaty, H. W. (2002). *Electrical Power Systems* 

323-328, ISBN 0-7803-7912-8, Rio de Janeiro, Brazil, June 9-11, 2003

*Quality*, McGraw-Hill, ISBN 0-07-138622-X, New York, USA

Networks, *Proceedings of 10th International Conference on Harmonics and Quality of Power*, pp. 208-213, ISBN 0-7803-7671-4, Rio de Janeiro, Brazil, October 6-9, 2002 Auler, L.F. & d' Amore, R. (2009). Power Quality Monitoring Controlled Through Low-Cost

Modules, *IEEE Transactions on Instrumentation and Measurement*, Vol.58, No.3,

PC, *Proceeding of ISIE'03 IEEE International Symposium on Industrial Electronics*, pp.

always concerned with the same primitive ideas and objectives.

(TRF), and Provincial Electricity Authority (PEA) for supports.

(March 2009), pp. 557-562, ISSN 0018-9456

Wiltshire, Great Britain

to separate the signal for testing each one in each phase that is easily studying.

From Fig. 17 shown above is an example of the interruption for a short time.

wares by executing more developed application programs that are shown in Fig. 12 and Fig. 13. The examples of the experimental result, that the data file is saved in the form of bitmap file (.BMP format) by the application program of Fig. 14, is illustrated in Fig. 15, Fig. 16 and Fig. 17.

Fig. 16. Zoomed signals of voltage sags from Fig.15(a)

Fig. 17. Interruption on phase A (measured on a single phase system)

Fig. 15(a) is the picture of sags for all 3 phases. The experimental results appeared in Fig. 15(b), (c) and (d) are the examples of sag in phase A, B and C chronically from Fig. 15(a). It is to separate the signal for testing each one in each phase that is easily studying.

Fig.16 is the zoomed picture from Fig. 15(a) to show the detail characteristics of the fault signals in each phase.

Another experiment of this chapter is applied to detect the fault on a single phase system. From Fig. 17 shown above is an example of the interruption for a short time.
