Explain the principle of operation of a synchrophasor measurement unit (PMU) and its application in wide-area monitoring systems.

A Synchrophasor Measurement Unit (PMU) is a device that measures the voltage and current phasors at a specific location in a power system and synchronizes these measurements with a common time reference. This time synchronization is achieved using the Global Positioning System (GPS), allowing for precise measurements of power system conditions across a wide area. The principle of operation involves several key steps. First, the PMU measures the voltage and current signals using high-accuracy instrument transformers. These signals are then filtered and sampled at a high rate. Second, the PMU uses a GPS receiver to obtain a precise time signal. This time signal is used to synchronize the measurements with a common time reference, typi....