**2.1 Signal conditioning modules (HCPL-788J)**

232 Electrical Generation and Distribution Systems and Power Quality Disturbances

phase or a 3-phase voltage measurement supported by the power quality monitoring hardware. When working in different places, we can establish the network in various sites and connect via the Ethernet network from a single PC or laptop. The network has the capability to send from the board site to the PC or laptop with high speed up to 100 megabit per second (Mb/s). Nevertheless, it is easy to monitor the power quality monitoring system

This chapter is organized as follow: Section 2 is the architecture of the power quality monitoring being composed of 2 sets of ARM7 microcontroller boards, 3 signal conditioning modules, external memory board and energy measurement board. Section 3 is the embedded software design with the details of sampling concept, power quality monitoring concept, data frames, configuration data and Ethernet packet structures. Section 4 is the application software to interface the power quality monitoring hardware. Section 5 is the experimental results which are displaying the fault signals from AC lines while being on operation or being done after. Section 6 is the conclusion from the research with the future

The architecture of the power quality monitoring system is planned for specific purposes which are to detect, to store, to download and to display the fault signals while being on operation or being done later on. The main structures are divided into 5 circuit boards. The block diagram of the architecture of the power quality monitoring system is shown in

Fig. 1. Block diagram of the architecture of the power quality monitoring system

via the Ethernet network from PC or laptop.

**2. Architecture of the power quality monitoring system** 

work suggestion.

Fig. 1.

There are actually 3 signal conditioning modules with 3 HCPL-788J integrated circuits for measuring the voltage of the three-phase AC lines in order to send the attenuated AC voltage to the waveform sampling board which the ADUC7024 microcontroller is embedded in. The 3 signal conditioning modules have used the same electronic circuit. The signal conditioning circuit is shown in Fig. 2.

Fig. 2. The circuit of the signal conditioning module

#### **2.2 The voltage and frequency measurement and fault detection board (ADE7758)**

This board is the key part of monitoring system of fault detection which refers to sags and overvoltages. In this chapter, ADE7758 integrated circuit has been chosen to operate because of its suitable qualification to detect the fault signals in time. The circuit of the board is shown in Fig. 3.
