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System and methods to detect, in real-time, occurrence of islanding and identify the location of islands in an interconnected power system based on synchrophasor measurements

IP.com Disclosure Number: IPCOM000249171D
Publication Date: 2017-Feb-08

Publishing Venue

The IP.com Prior Art Database

Related People

Adamantios Marinakis: INVENTOR [+3]

Abstract

Contingencies in power systems may lead to (cascading) line trips and eventually to islanding of the system in two or more disconnected networks. It is paramount for the system operator to quickly detect that an islanding has occurred as well as identify the location of each island, in order to take actions (like generation redispatch, generation tripping, load shedding) that will quickly balance generation and demand in each island. In addition, generation setpoints may need to be adjusted so that the generators maintain frequency and thus power balance in the island where they are located. Last, islanding detection and island localization is very important in system restoration after outages caused by natural disasters (e.g. hurricane Katrina). If the islanding situation is not detected fast enough, islands with large power imbalance will experience significant frequency drops or raises and eventually go to instability. Detection of islanding is important even for islands which happen to be balanced after the islanding occurrence; each island should be controlled as such, otherwise control actions may unintentionally destabilize an otherwise stable island. The present invention discloses a system and method to detect, in real-time, occurrence of islanding and identify the location of islands in an interconnected power system based on synchrophasor measurements.

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 Type of document Classification Information for filing

Invention Disclosure ABB Ref.: CH-1524301 Pl. from Dept. Inventors

Date Pages

Dä CHCRC/Automation Adamantios Marinakis, Mats Larsson, Alexandru Moga 2017-02-06 1/12

Title

System and methods to detect, in real-time, occurrence of islanding and identify the location of islands in an interconnected power system based on synchrophasor measurements

We reserve all rights in this document and in the information contained therein. Reproduction, use or disclosure to third parties without express authority is strictly forbidden.  ABB Ltd. 2017

1. Background Brief statement of how things worked before the invention

Contingencies in power systems may lead to (cascading) line trips and eventually to islanding of the system in two or more disconnected networks. It is paramount for the system operator to quickly detect that an islanding has occurred as well as identify the location of each island, in order to take actions (like generation redispatch, generation tripping, load shedding) that will quickly balance generation and demand in each island. In addition, generation setpoints may need to be adjusted so that the generators maintain frequency and thus power balance in the island where they are located. Last, islanding detection and island localization is very important in system restoration after outages caused by natural disasters (e.g. hurricane Katrina).

If the islanding situation is not detected fast enough, islands with large power imbalance will experience significant frequency drops or raises and eventually go to instability. Detection of islanding is important even for islands which happen to be balanced after the islanding occurrence; each island should be controlled as such, otherwise control actions may unintentionally destabilize an otherwise stable island.

Many methods for power system islanding detection rely on topology information, such as the status of circuit breakers or switches. This information, communicated to a central computer, is processed in real-time by some algorithm which eventually detects islanding. Such islanding detection algorithms typically belong into one of the following categories: linked in approaches, numerical methods and graph-theoretic schemes. See [1] and its references for examples of such methods.

Apart from methods to detect system-wide islanding, there exists a plurality of methods to detect that a part of the system (usually a distribution network) has been islanded with respect to the rest of the network. These methods typically rely of real-time observation of electric measurements such as frequency, voltages, currents and phase angles. They are classified as either passive, if they rely solely on observation of electric measurements, or active, if they, in addition, rely on injecting a signal into the network in order to observe its behavior and conclude from this whether an islanding has occurred. A summary of the main passive methods to det...