The greatest threat to the operational stability of any system is the one that the operator does not see. In order to assist grid operators in the early detection of such threats, GE is providing Southern California Edison (SCE) with a phasor measurement system to acquire, monitor, visualize, analyze, archive and share phasor measurement information.

In contrast to traditional supervisory control and data acquisition systems that acquire measurements at rates of 2 seconds to 10 seconds, GE's phasor measurement system acquires measurements of underlying grid conditions from phasor measurement units (PMUs), located within SCE's system as well as neighboring utilities, at a rate of 30 times per second, providing operators with visibility to power system dynamics and a real-time wide-area view of the grid.

The phasor project, also known as a wide-area situational awareness system, involves the deployment of PMU devices in 500-kV and 230-kV substations throughout SCE's network and their integration with associated situational awareness applications at the grid control center. The solution provides real-time monitoring of power flows, voltage magnitudes and phase-angle differences between utility substation buses as well as frequency and its associated rate of change. The design of the system also accommodates the incorporation of supplemental information from other sources such as energy management systems and non-electrical system data (weather, traffic, fire, earthquake, etc.) to provide a holistic real-time view of the electrical grid for system operators.

For more information, visit www.ge.com