**2. Background**

In this section, a brief background and history of WAMS are provided. Then, the accurate definition of WAMS will be introduced.

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processing. Measurement systems and communication systems together with energy

In general, a WAMS acquires system data from conventional and new data resources, transmits it through communication system to the control center(s) and processes it. After extracting appropriate information from system data, decisions on operation of power system are made. Occasionally, WAMS may command some actions that are performed by system actuators in remote sites (Shahraeini et al., 2011). All of these facts indicate that WAMS denotes efficient usage of data and data flow to achieve a more secure and a better

An inspection of the above-mentioned facts together with Fig. 1 indicates that data itself is the fundamental requirement to perform WAMS functions. It can also be concluded that each sub-process has different responsibilities and different tasks that should be performed on system data. Consequently, WAMS main sub-processes should be studied from the data

In the rest of this chapter, data resources, applications and communication infrastructure of

Online data and information from the entire system have been essential for secure operation and control of interconnected systems e.g. power systems. In general, system data and information have been provided by data resources of system, which are also called measuring devices (Shahraeini et al., 2010). Data provided by data resources are widely different in terms of their importance, format, volume, sample rate and etc. Thomas et al. (2006) have classified power system data into two main data groups: Operational and Non-

The operational data includes the instantaneous measurements of voltages, currents, phasors and breaker statuses that are measured by intelligent devices. Such data is transmitted continuously to the control center(s) through communication systems.

Occasionally, they may be used locally for the local decision making.

strategy for the flow of electrical energy. The WAMS process is illustrated in Fig. 1.

management systems perform these sub-processes, respectively.

Fig. 1. WAMS Process in Power Systems.

point of view.

Operational data.

WAMS will be investigated.

**4. Data resources of WAMS** 
