# Smart Grid Fault Mitigation and Cybersecurity with Wide-Area Measurement Systems: A Review
## 1 Introduction  
Developing a resilient, reliable, and secure power system is central to modern economic development. Increasingly, such a grid also serves sociocultural and security goals. Yet, maintaining such a power system has become more challenging in recent years due to rising energy demand, the densification of population centers, climate change effects, and aging power infrastructure [1]. Grid stability and reliability are also threatened by the introduction of renewable power generation, which is often intermittent, nonsynchronous, or volatile [2]. While costly maintenance and upgrades are common responses to these challenges, more affordable improvement measures are often out of reach, especially for developing countries [3]. Over the years, power system restructuring has been the primary way of expanding power system operations. Complex measurement systems are essentialfor controlling the network in day-to-day generation, transmission, and distribution of energy [3; 4]. Consequently, the modern-day focus of power system development is optimizing the present architecture responsible for accurate and adequate energy delivery [4; 5]. On the software side, demand-side management and load shifting are being employed to these ends [6; 7]. On the hardware side are many approaches involving relays, which have many shortcomings, including an inability to simultaneously report multiple parameters in real time. These shortcomings, in turn, were initially addressed using a supervisory control and data acquisition (SCADA) platform. SCADA could report multiple energy parameters to control towers across the network in real time [5]. SCADA measurements are typically updated in a ten-second window for high-level operations, which is unfortunately not granular enough to prevent certain faults [8; 9]. SCADA's limitations have made us unable to reduce fault occurrence on power networks, and in most cases, SCADA increases the fault-clearing time [4]. Since neither relays nor generic SCADA address the rising issue of faults plaguing the power network, grid managers increasingly adopt synchrophasors. These increase the number of parameters like voltage, current, resistance, and impedance measured per unit time on the power system network [10]. The general introduction of synchrophasors, phasor measurement units (PMUs), and critical communication systems into the power system infrastructure results in it being termed a Wide-Area Measurement System (WAMS) [11; 12]. WAMS infrastructure connected to the power system network relies on communication utilities to detect faults on the transmission lines using synchrophasors. WAMS then reports these data to the control centers for proper decisions to predict faults, correct faults, and improve consumer energy supply (as shown in Figure 1) [8; 13; 14]. This study reviews research on WAMS to apply them to developing countries' power systems, specifically to reduce fault-clearing time, improve cybersecurity, and make conventional power systems smart in these regards. To this end, this review analyzes the individual components of WAMS communication architecture. It details their potential for reducing fault-clearing time to increase the efficiency of energy delivery, all while maintaining cybersecurity. Figure 1: Schematic of a typical WAMS implementation [15]. Modern power systems are characterized by their intricate architectures, comprising numerous components and complex interconnections to ensure stable and reliable operation. However, the occurrence of faults--whether due to equipment failure, environmental factors, or other disruptions--can severely compromise energy flow and supply across the network. Even microgrids, which represent a transformative approach to power system design through the integration of Distributed Energy Resources (DERs), are not exempt from these vulnerabilities [16].