Field measurement of frequency and ROCOF in the presence of phase steps

Paul S. Wright, Peter N. Davis, Kevin Johnstone, Gert Rietveld, Andrew J. Roscoe

Research output: Contribution to journalArticle

2 Citations (Scopus)
10 Downloads (Pure)

Abstract

A description of the importance of rate of change of frequency (ROCOF) measurements to the operation of electricity networks is given. The susceptibility of ROCOF measurements to common power system disturbances such as phase steps is described. A measurement campaign to observe ROCOF at multiple locations in an island grid dominated by renewable generation is described and some results are given. These captured ROCOF events are dominated by those associated with phase steps, which occur without significant change to underlying power system frequency. It is concluded that they constitute a “false” ROCOF event. A new algorithm is presented that attempts to remove the influence of the phase step and reduce the associated ROCOF error such that the reliability of ROCOF measurements can be improved in the presence of phase steps. The algorithm is then applied to some recorded waveform sequences from the island that contain phase steps and the results are presented. In one example, it is shown that a false ROCOF spike in excess of 100 Hz/s was reduced to less than 5 Hz/s.
Original languageEnglish
Number of pages8
JournalIEEE Transactions on Instrumentation and Measurement
DOIs
Publication statusPublished - 11 Dec 2018

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frequency measurement
Electricity
electricity
spikes
waveforms
disturbances
grids
magnetic permeability

Keywords

  • phasor measurement units (PMU)
  • frequency measurement
  • rate-of-change-of-frequency (ROCOF)
  • power system measurements

Cite this

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title = "Field measurement of frequency and ROCOF in the presence of phase steps",
abstract = "A description of the importance of rate of change of frequency (ROCOF) measurements to the operation of electricity networks is given. The susceptibility of ROCOF measurements to common power system disturbances such as phase steps is described. A measurement campaign to observe ROCOF at multiple locations in an island grid dominated by renewable generation is described and some results are given. These captured ROCOF events are dominated by those associated with phase steps, which occur without significant change to underlying power system frequency. It is concluded that they constitute a “false” ROCOF event. A new algorithm is presented that attempts to remove the influence of the phase step and reduce the associated ROCOF error such that the reliability of ROCOF measurements can be improved in the presence of phase steps. The algorithm is then applied to some recorded waveform sequences from the island that contain phase steps and the results are presented. In one example, it is shown that a false ROCOF spike in excess of 100 Hz/s was reduced to less than 5 Hz/s.",
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Field measurement of frequency and ROCOF in the presence of phase steps. / Wright, Paul S.; Davis, Peter N.; Johnstone, Kevin; Rietveld, Gert; Roscoe, Andrew J.

In: IEEE Transactions on Instrumentation and Measurement , 11.12.2018.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Field measurement of frequency and ROCOF in the presence of phase steps

AU - Wright, Paul S.

AU - Davis, Peter N.

AU - Johnstone, Kevin

AU - Rietveld, Gert

AU - Roscoe, Andrew J.

PY - 2018/12/11

Y1 - 2018/12/11

N2 - A description of the importance of rate of change of frequency (ROCOF) measurements to the operation of electricity networks is given. The susceptibility of ROCOF measurements to common power system disturbances such as phase steps is described. A measurement campaign to observe ROCOF at multiple locations in an island grid dominated by renewable generation is described and some results are given. These captured ROCOF events are dominated by those associated with phase steps, which occur without significant change to underlying power system frequency. It is concluded that they constitute a “false” ROCOF event. A new algorithm is presented that attempts to remove the influence of the phase step and reduce the associated ROCOF error such that the reliability of ROCOF measurements can be improved in the presence of phase steps. The algorithm is then applied to some recorded waveform sequences from the island that contain phase steps and the results are presented. In one example, it is shown that a false ROCOF spike in excess of 100 Hz/s was reduced to less than 5 Hz/s.

AB - A description of the importance of rate of change of frequency (ROCOF) measurements to the operation of electricity networks is given. The susceptibility of ROCOF measurements to common power system disturbances such as phase steps is described. A measurement campaign to observe ROCOF at multiple locations in an island grid dominated by renewable generation is described and some results are given. These captured ROCOF events are dominated by those associated with phase steps, which occur without significant change to underlying power system frequency. It is concluded that they constitute a “false” ROCOF event. A new algorithm is presented that attempts to remove the influence of the phase step and reduce the associated ROCOF error such that the reliability of ROCOF measurements can be improved in the presence of phase steps. The algorithm is then applied to some recorded waveform sequences from the island that contain phase steps and the results are presented. In one example, it is shown that a false ROCOF spike in excess of 100 Hz/s was reduced to less than 5 Hz/s.

KW - phasor measurement units (PMU)

KW - frequency measurement

KW - rate-of-change-of-frequency (ROCOF)

KW - power system measurements

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