Bi-annual Newsletters Vol. 2 | Page 5

research highlights
Phasor-Based State Estimation
Over the last three years, the quantity and quality of synchrophasor measurements made on the U.S. electric
grid have dramatically increased. In addition, the performance and robustness of the systems used to collect
and manage this high-sample rate, GPS time-stamped data have greatly improved. The number of real-time
phasor measurements in some Reliability Coordinator control rooms is now approaching the level needed
for full analysis of the electric grid through synchrophasor measurements alone. This full analysis requires
a real-time phasor state estimation (RTP-SE) developed in the Modeling and Estimation Thrust, and is an
enabling technology for wide-area measurements.
The RTP-SE will be based on synchrophasor measurements; it will be able to cycle at least at a one-second
interval; and it will provide unprecedented capability to:
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Calculate “pseudo” PMU measurements at unmeasured buses and lines
Correlate PMU data across a network, allowing data quality enhancement and filling in missing data
Enable interface flow calculation even though not all flows are directly measured with PMUs
Monitor generator (fossil and wind turbine) active and reactive power outputs without implementing a
PMU at the generator substation
High-sampling-rate allows dynamic visibility of disturbances (voltages and power flows), disturbance
propagation, frequency response, and oscillations
Establish real-time models to determine stability margins
In July 2104, Rensselaer Polytechnic Institute
submitted a proposal to the NSF SECO
project, led by Grid Protection Alliance (GPA).
The objective of the proposal is to develop,
test, demonstrate and commercialize the RTPSE. The project team believes that the RTPSE is necessary, if not critical, to realizing the
full value from synchrophasor measurements.
Through the capabilities enumerated above,
the RTP-SE will provide more complete, higher
quality and more reliable synchrophasor data
streams for use by control center applications
and operators.

The RTP-SE solution will be built as a commercial extension of GPA’s Grid Solutions Framework© (GSF).
This free, open source library of software is in production use in many control rooms in North America
and is the foundational component for GPA’s open source product offerings such as the open phasor data
concentrator (openPDC). Using this proven, extensible framework simplifies the implementation of the
RTP-SE and allows the project to focus effort on the development of the state estimation analytics – or the
“Phasor State Estimator Adapter” (PSE-Adapter). Use of the GSF also provides an easy path to utilization
and commercialization.
The PSE-Adapter will be developed by RPI based on previous work that was supported by CURENT and on
synchrophasor measurements from the Central New York Power System. The adapter will be refined and
improved using data from the New England Power System and additional portions of New York State.
The National Science Foundation has informed the project team that the project has been selected for
funding, and contract negotiations are underway.

newsletter Spring 2014

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