T&D World Magazine

MISO Achieves Synchrophasor Milestone

As part of a national effort to modernize the grid, MISO and its members have achieved a major milestone in their three-year smart grid program to install sophisticated electronic measurement devices known as synchrophasors across the region, completing the integration of 44 such devices at strategic points along the regional transmission network. The $34.5 million program is funded partly by $17.3 million in Recovery Act stimulus funds awarded by the U.S. Department of Energy to modernize the nation's electrical grid.

Representatives from the DOE's Office of Electricity Delivery and Energy Reliability, which manages the $3.4 billion Smart Grid Investment Grant (SGIG) program, visited MISO to review progress on the deployment of the first round of the devices, known as phasor measurement units or PMUs. The synchrophasor program, which began March 30, 2010, aims to deploy 165 PMUs at strategic substations in the MISO region.

"Synchrophasors bring a new level of situational awareness to grid operators," said MISO President and Chief Executive Officer John R. Bear. "The ultimate goal of this three-year project is to enhance visibility of the network in real time so we can more quickly and accurately manage power flows within the Eastern Interconnection. Collaboration with our members on this smart grid technology has laid the foundation for using these advanced tools to enhance awareness of system stability."

Synchrophasors will allow MISO's grid operators to view vital measurements of real-time system conditions at a detailed level previously impossible to reach. PMUs collect data 30 times every second, faster than the previous once every four seconds. Plus they are GPS time-stamped. Understanding time-synchronized measurements for voltage and current as well as frequency – the "pulse" of the grid – provides grid operators with a powerful visualization tool to anticipate and analyze potential disturbances. Synchrophasors also provide data essential for post-mortem analysis of stressful situations on the grid.

Stresses on the system - such as increased power transfers, line outages and loss of generation - can cause power angles to "separate indicating stress on the system." Large angles have often been observed to precede large-scale blackouts. Tools such as PMUs allow operators to visualize the angle separation and alert them when the angles indicate the system is becoming potentially unstable. This improved knowledge of system health allows MISO and its members to jointly take corrective actions to prevent unusual fluctuations in frequency and possible voltage collapse.

MISO is now collecting synchrophasor data from the 44 member PMUs installed on 10 of its members' systems. As part of this week's site visit, the DOE representatives from the Office of Electricity Delivery and Energy Reliability visited a substation at Indianapolis Power & Light Company (IPL), which has installed seven units at six of its substations.

"The partnership and collaboration between IPL and MISO has been outstanding during this Smart Grid Investment Grant project," said Joe Bentley, IPL's Vice President, Power Delivery. "The PMUs are giving us a better understanding of our transmission system while providing valuable real-time data to MISO for overall transmission grid reliability."

Other MISO members in the project include: Ameren, Duke Indiana, Great River Energy, Hoosier Energy, International Transmission Co., Manitoba Hydro-Electric Board, MidAmerican Energy Company, Minnesota Power, Northern Indiana Public Service Co., Otter Tail Power Company, and Vectren Corporation. More MISO members may join the program soon.

The next phase of the project consists of developing applications that will analyze the data collected so operators will have a clearer picture of stress points on the grid and can make adjustments accordingly.

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