**4.1 Supervisory Control and Data Acquisition (SCADA)**

SCADA is a generic name for a computerized system, which is capable of gathering and processing data and applying operational controls over long distances. Typical uses of SCADA include power transmission and distribution and pipeline systems (Friedmann, 2003).

In an electrical power system, a SCADA system provides three critical functions in the operation of such a system (Jelatis, 2001):


In general, a SCADA system consists of both hardware and software. Typically, SCADA hardware may include three parts: Master Terminal Unit (MTU), Remote Terminal Unit (RTU), and Communication System (Stouffer et al., 2008). It should be noted that sometimes Programmable Logic Controllers (PLCs) or Intelligent Electronic Devices (IDEs) may be used as RTU in SCADA systems (Clarke et al., 2004).

The simplest form of SCADA hardware includes: an MTU that located in the control center, one remote field site consisting of either an RTU or a PLC or an IED, and a communication system that provides communication route between remote site and the control center. Fig. 2 shows SCADA sub-systems (Stouffer et al., 2008). Brief descriptions of SCADA sub-systems are as follows:

On the other hand, the non-operational data basically consists of records or logs of multiple events e.g. series of faults, power fluctuations, disturbances and lightning strikes. Typically, the non-operational data is offline data. This means that they are transmitted to the control center(s) either in the specified time intervals (e.g. multiple hours) or when they are

There are two main differences between the operational and the non-operational data. The first one is their polling rates. The operational data are normally polled in a regular mode i.e. a continuous stream of data. On the other hand, most of the non-operational data are polled at the defined conditions or they are periodically polled at a specified time intervals. Another major difference is their data format. The operational data is usually transmitted in the form of a stream i.e. stream of numerical variables. While the non-operational data may appear in different formats e.g. waveforms, numerical values, COMTRADE (COMmon

In this book, the classification of power system data represented by Thomas et al. (2006), is generalized to the data resources of power systems as well. In this section, these two classes of data resources; i.e. operational and non-operational data resources; are summarized in separate subsections. Supervisory Control and Data Acquisition (SCADA) and Synchronized Phasor Measurement System (SPMS) are two operational data resources that will be studied. Alternatively, Digital Fault Recorder (DFR), Digital Protective Relay (DPR) and Circuit Breaker Monitor (CBM) will be investigated as non-operational data resources.

SCADA is a generic name for a computerized system, which is capable of gathering and processing data and applying operational controls over long distances. Typical uses of SCADA include power transmission and distribution and pipeline systems (Friedmann,

In an electrical power system, a SCADA system provides three critical functions in the

In general, a SCADA system consists of both hardware and software. Typically, SCADA hardware may include three parts: Master Terminal Unit (MTU), Remote Terminal Unit (RTU), and Communication System (Stouffer et al., 2008). It should be noted that sometimes Programmable Logic Controllers (PLCs) or Intelligent Electronic Devices (IDEs) may be

The simplest form of SCADA hardware includes: an MTU that located in the control center, one remote field site consisting of either an RTU or a PLC or an IED, and a communication system that provides communication route between remote site and the control center. Fig. 2 shows SCADA sub-systems (Stouffer et al., 2008). Brief descriptions of SCADA sub-systems

format for TRAnsient Data Exchange) format etc. (Thomas et al., 2006).

**4.1 Supervisory Control and Data Acquisition (SCADA)** 

operation of such a system (Jelatis, 2001):

used as RTU in SCADA systems (Clarke et al., 2004).

requested by the system operator.

2003).

 Data acquisition Supervisory control Alarm display and control

are as follows:

Fig. 2. SCADA sub-systems (Stouffer et al., 2008).
