Electricity: electrical systems and devices – Safety and protection of systems and devices – With specific quantity comparison means
Reexamination Certificate
2000-03-21
2002-08-13
Tso, Edward H. (Department: 2838)
Electricity: electrical systems and devices
Safety and protection of systems and devices
With specific quantity comparison means
Reexamination Certificate
active
06433980
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a controlled switching device for controlling open and close timing of a breaker and for preventing a harmful phenomenon for a system and an apparatus from occurring, in particular, to a structure of a control device for the controlled switching device.
2. Discussion of Background
Japanese Unexamined Patent Publication JP-A-3-156820 discloses a controlled switching device, which does not generate a transitional phenomenon influencing systems and apparatuses regardless of a make break condition. In such a controlled switching device, a device for controlling timing of opening a pole is provided in a breaker so that contacts are sufficiently spaced at time of cutting off a current. Further, the device for controlling the timing of opening the pole controls timing of closing the pole in the breaker in response to a type of a load.
Japanese Unexamined Patent Publication JP-A-6-20564 discloses an open control device for a breaker used as a shunt reactor, in which a pole is opened without reigniting. In the open control device for the breaker, because a high frequency reignition surge generated at time of opening the pole of shunt reactor does not exist when a final breaking point of the breaker is a current phase zero point, a single-phase voltage is inputted into the control device from an instrument transformer. In the control device, each current phase is calculated based on a phase of the single-phase voltage and outputs a command of opening the pole to the breaker so that a current, which flows through the shunt reactor, is cut off at a current zero point of each phase.
In the above-mentioned control devices, a control signal is outputted to control close timing or open timing by detecting a zero point of a current or a voltage of a main circuit after a close command or an open command is input and by changing a time for urging a releasing device or the device for controlling to close the pole based on the detected zero point. Therefore, it is necessary to wait for the time from inputting the close command or the opening command until detecting the next voltage zero point or the next current zero point. Resultantly, there is a problem that a dead time of a maximum of one cycle occurs between the input of the closing command or the opening command and the corresponding actuation of the switch.
Further, an operating time of the breaker is corrected by a correction curve of a control voltage expressed by a primary expression or a secondly expression, and the breaker does not have a function of dealing with a displacement of the acting time by an environmental temperature change, that between devices, that between phases, that caused by aged deterioration, and so on. Therefore, there is a problem that a function of constantly closing or opening the pole at predetermined timing is hardly realized.
Further, there is a problem that the zero point is not accurately detected when a sudden noise of an impulse type or a higher harmonic is superposed on a detection signal when the zero point of the current or the voltage is detected. Also, there is a problem that the pole is not closed or opened at a predetermined time when a frequency varies because the control device does not respond to frequency variation of the voltage or the current.
SUMMARY OF THE INVENTION
It is an object of the present invention to solve the above-mentioned problems inherent in the conventional technique and to provide a controlled switching device, which outputs a close control signal or an open control signal after latency of a half cycle or less with respect to a close command or an open command when a pole is closed or opened at predetermined timing with respect to the close command or the open command and can make a breaker at a predetermined interpole voltage phase or can open the pole at a predetermined phase of a main open current.
According to a first aspect of the present invention, there is provided a controlled switching device comprising a control device which acquires a zero interpole voltage time of a breaker preceeding and closest to a close command, a close command detection time from the zero interpole voltage time to a detection of the close command, a predicted closing time from an output of a close control signal to a close of a pole, and a pre-arc time from making to closing the pole based on a target phase, acquires close control latency on a premise that it is possible to make at a target phase by outputting the close control signal after a lapse of the close command detection time and the close control latency of less than a half period of an interpole voltage from the zero interpole voltage time, and outputs the close control signal after a lapse of the close control latency from the detection of the close command.
According to a second aspect of the present invention, there is provided the controlled switching device according to the first aspect of the invention, wherein continuous evaluated zero point times as much as a predetermined number preceeding and closest to the close command are used as the zero interpole voltage time; a minimum deviation of latency between one of the evaluated zero point times and the other evaluated zero point times from products of a half period of the breaker interpole voltage and integers is acquired; the zero interpole voltage time is rendered to be a time after a lapse of times as much as a product of a half period and integers from one of the evaluated zero point times closest to a detection time of the close command just before detecting the close command, wherein the one is selected from the evaluated zero point times having a minimum sum of absolute values of the minimum deviations.
According to third aspect of the present invention, there is provided the controlled switching device according to the first aspect of the invention, wherein the predicted close time is acquired by correcting a reference close time under a standard environmental condition by a close time correction table based on an environmental condition.
According to a fourth aspect of the predict invention, there is provided the power make brake device according to the first aspect of the invention, wherein an observation close time is acquired from a contact time of a contact at a close operation, which is detected by a close time detection means interlocked with a movable contact and an output time of the close control signal; and a reference close time is corrected by a close time correction table based on an environmental condition.
According to a fifth aspect of the present invention, there is provided the controlled switching device according to the first aspect of the invention, wherein an observation close time is obtained by detecting a rise time of a main circuit current at time of closing and adding a pre-arc time to latency of the rise time from an output of the close control signal; and a reference close time is corrected by a close time correction table based on an environmental condition.
According to a sixth aspect of present invention, there is provided the controlled switching device according to the first aspect of the invention, wherein continuous zero point times as much as a predetermined number preceeding and closest to the close command are used to acquire local frequencies of the breaker interpole voltage from a frequency between adjacent zero point times, and a frequency of the breaker interpole voltage is an average of the local frequencies.
According to a seventh aspect of present invention, there is provided the controlled switching device comprising a control device, which acquires a main circuit current zero point time, an open command detection time between the main circuit current zero point time and detection of the open command, and a predicted open time between an output of an open control signal and an open of a pole, acquires an open control delaying time on a premise that the pole is opened at a target phase when the open control signal is outputted after a l
Hirai Takashi
Tsutada Hiroyuki
Leydig , Voit & Mayer, Ltd.
Mitsubishi Denki & Kabushiki Kaisha
Tibbits Pia
Tso Edward H.
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