Title:
SYSTEM FREQUENCY DETECTOR
Document Type and Number:
WIPO Patent Application WO/2021/240639
Kind Code:
A1
Abstract:
An embodiment of the present invention provides a system frequency detector provided with: an orthogonal-coordinate-signal generation unit that generates orthogonal two-phase voltage signals from three-phase voltage signals in an electric power system; and a frequency calculation unit including an angular-frequency calculation unit that calculates the angular frequency of the electric power system on the basis of the two-phase voltage signals and also including a calculator that calculates the system frequency of the electric power system from the angular frequency. The frequency calculation unit includes a prediction calculator that calculates a predictive value of the angular frequency after the elapse of a prescribed time on the basis of the angular frequency and derivative values of the angular frequency. The frequency calculation unit calculates the system frequency on the basis of the angular frequency in a state in which a phase jump in the electric power system has not been detected, while calculating the system frequency on the basis of the predictive value only for a certain time when a phase jump in the electric power system has been detected. Accordingly, the embodiment of the present invention provides a system frequency detector that is capable of following changes in the system frequency at high speed and suppressing incorrect detection of the system frequency even when a system disturbance has occurred.
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Inventors:
MITSUGI YASUAKI (JP)
SHIGEMASA TAKASHI (JP)
SHIGEMASA TAKASHI (JP)
Application Number:
PCT/JP2020/020722
Publication Date:
December 02, 2021
Filing Date:
May 26, 2020
Export Citation:
Assignee:
TOSHIBA MITSUBISHI ELECTRIC INDUSTRIAL SYSTEMS CORP (JP)
International Classes:
G01R23/02; G01R23/12; H02J13/00
Foreign References:
| JP2012163543A | 2012-08-30 | |||
| JPH06284560A | 1994-10-07 | |||
| JP2013092473A | 2013-05-16 | |||
| JP2004064515A | 2004-02-26 | |||
| JPH075212A | 1995-01-10 | |||
| US20160301328A1 | 2016-10-13 | |||
| US20130116946A1 | 2013-05-09 |
Other References:
See also references of EP 4160228A4
Attorney, Agent or Firm:
HYUGAJI, Masahiko et al. (JP)
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