US 6,172,863 B2Granted

Phase control switching system

AssigneeMitsubishi Denki Kabushiki Kaisha

InventorsHiroki Ito, Haruhiko Kohyama, Mikio Hidaka

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Abstract

A phase control switching system for controlling opening and closing timings of a power switching device to suppress the occurrence of an exciting rush current or a make-and-break surge voltage which is severe to system equipment such as a transformer, a reactor and a capacitor bank, or for controlling an arcing time of a circuit breaker to put the circuit breaker into operation for the arcing time leading to no-re-ignition or for the optimal breaking time. In the phase control switching system, a current measuring section or a current gradient measuring section is provided to measure a current value or a current gradient value of a current to be broken or introduced, and a reference phase detecting section estimates a current zero point of a current waveform on the basis of the measurements. Subsequently, a control section, upon receipt of an opening/closing command, an opening phase control operation using an arbitrary time point after the current waveform estimation as a reference.

Claims8

Dependent claims

A phase control switching system comprising:

a power switching device provided in a power system for breaking a current including a short-circuit fault current and a load current or introducing it into a system voltage in response to an opening and closing command;
waveform measuring means for measuring one of a voltage waveform and a current waveform said power switching device makes and breaks;
current zero point estimating means for estimating a plurality of zero points of a current with a commercial frequency on the basis of the measured one of said voltage waveform and said current waveform;
parameter measuring means for measuring parameters which affect an operation time of an operating mechanism of said power switching device;
operation time estimating means for estimating an opening operation time of said power switching device on the basis of the measured parameters;
current zero point selecting means for setting a breaking time comprising a predetermined arcing time plus said opening operation time, so that a breaking point forming a current zero point is reached at the point of time of the elapse of said predetermined arcing time, said zero point selecting means being further operable to select that one current zero point from said plurality of current zero points which is estimated to occur after the elapse of the set breaking time from a present reference time point to set the selected current zero point as a desired breaking point;
and
operation starting means for calculating an operating synchronization time on the basis of said breaking time and a difference between a time from said present reference time point to said desired breaking time, and for outputting a control operation command to said power switching device after the elapse of said operating synchronization time from said reference time point so that said power switching device starts its operation.

5 more elements

A phase control switching system comprising:

a power switching device provided in a power system for breaking a current including a short-circuit fault current and a load current or introducing it into a system voltage in response to an opening and closing command;
voltage waveform measuring means for measuring one of a voltage waveform and a current waveform said power switching device makes and breaks;
voltage zero point estimating means for estimating the time points of a plurality of periodic inter-pole voltage zero points on the basis of the measured one of said voltage waveform and said current waveform;
means for measuring parameters including main temperatures, an operating force and a control voltage which affect an operation time of an operating mechanism of said power switching device;
operation time estimating means for estimating an opening operation time on the basis of the measured parameter values;
make time setting means for, in consideration of a predetermined previous arcing time, setting a make time obtained by subtracting said previous arcing time from a closing operation time so that said power switching device is electrically turned on at a predetermined make time point;
desired breaking point selecting means for selecting one time point from make electric angles set to occur after the elapse of the set make time from a present reference time point and for setting the selected time point as a desired breaking point;
and
operation starting means for subtracting the make time from a time from the present reference time point to said desired breaking point and further for adding said previous arcing time to the subtraction result to calculate an operating synchronization time, and still further for issuing a control operation command to said power switching device at the point of time of the elapse of said operating synchronization time from said reference time point to start an operation of said power switching device.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/339,678Filed 24 Jun 1999
Priority: JP 10-36290521 Dec 1998
Granted: 9 Jan 2001
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

H01H 33/593
Circuit arrangements not adapted to a particular application of the switch and not otherwise provided for, e.g. for ensuring operation of the…:…
H01H 33/006
High-tension or heavy-current switches with arc-extinguishing or arc-preventing means: adapted for interrupting fault currents with delayed zero…
Y10S 323/908
Electricity: power supply or regulation systems: inrush current limiters
H01H
Electric switches