Subharmonic power line carrier based island detection systems and methods
| DWPI Title: Method for eliminating island condition in feeder of power grid by e.g. photovoltaic cells, involves detecting presence or absence of voltage signal using receiver, and disconnecting energy source from feeder when signal is absent |
| Abstract: Systems and methods for identifying an island condition in a power distribution system and disconnecting distributed generators in the case of islanding. The systems and methods are used to enable reliable detection of island formation with high false-trip immunity, for any combination of distributed energy resources, and for distributed energy resources using grid support functions. |
| Use: Method for eliminating an island condition in a feeder of a power grid by distributed energy resources e.g. photovoltaic cells, wind-powered generator and fossil-fuel powered generator (all claimed). |
| Advantage: The method enables using a smaller and less expensive transformer and enhanced flexibility in an amplitude, waveform and frequency of an injected signal. The method enables providing optimization for improvements in propagation properties, and minimizing harmonic injection problems on specific circuits. The method enables utilizing upstream from a substation, thus avoiding costs associated with installation inside substation perimeter. The method enables providing reliable detection of island formation in the presence of distributed energy resources. |
| Novelty: The method involves using a transmitter (86) to inject a subharmonic voltage signal into a power grid through an injection transformer (114) coupled in series with a feeder on a power grid side of a switch. A receiver on a distributed energy source (126) side of the switch is coupled to the power grid and the feeder. The presence or absence of the subharmonic voltage signal is detected using the receiver. The distributed energy source is disconnected from the feeder when the subharmonic voltage signal is absent. |
| Filed: 7/18/2016 |
| Application Number: US15213191A |
| Tech ID: SD 13390.1 |
| This invention was made with Government support under Contract No. DE-NA0003525 awarded by the United States Department of Energy/National Nuclear Security Administration. The Government has certain rights in the invention. |
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