Exploring PJM: PJM’s synchrophasor program


This is Part One of a two-part story. Part Two will run the week of Nov. 20.

Situational awareness is a key component of PJM Operations and paramount to the safe, smart operation of the electric grid.

Synchrophasors have become a significant part of those operations and are instrumental to the electric grid in the 21st century. These monitoring devices take high-speed measurements of voltage, current and frequency. They improve operators’ visibility of the grid by painting a more detailed and clearer picture of the transmission system at any given moment. This allows operators to make decisions to prevent power outages.

PJM is working with its members and leading industry organizations to support research and deployment of synchrophasor technology, which allows system operators to study the electric grid in new and deeper ways.

Ryan Nice, senior lead engineer – Operations, said the PJM synchrophasor program has developed tools that can better detect instances such as oscillations and wide-area disturbances. These can be triggered by things such as line switching or a sudden change of generator output.

“The most valuable thing this technology does is give dispatchers and operators the right insights – both while and before things are happening – to allow them to make the best decisions possible,” said Nice.

About synchrophasors 

Synchrophasors use monitoring devices, called phasor measurement units, to take high-speed measurements of voltage, current and frequency. The high-speed measurements, typically taken 30 times a second, are time-stamped with signals from global positioning system satellites.

The high-speed measurements make it possible to reveal system changes undetectable through traditional monitoring systems. This enables data from different locations and utilities to be time-synchronized and combined to create a detailed, comprehensive view of the broader system.

These improvements make possible valuable new energy management applications.

Before 2010 or so, synchrophasor technology was “there,” but not much else, as there  were fewer than 200 PMUs in the United States.

Now, there are more than 2,500 networked PMUs across the country. Some of this growth occurred as a result of a $14 million-stimulus grant from the U.S. Department of Energy.

Since 2013, PJM and its member transmission owners have installed close to 400 PMUs in over 100 substations in 10 different states.