The present invention relates to a method of, and a device for, controlling opening and closing a circuit breaker, and more particularly, to controlling the circuit breaker by minimizing noise impact on a zero-crossing detect. In other words, the present invention relates to the method of, and the device for, controlling the opening and closing of the circuit breaker without any delay by minimizing noise impact over the zero-crossing detect.
In general, a circuit breaker or CB refers to a device of keeping safety by performing a function of supplying which supplies power to load and a function of opening which turns off a load circuit upon fault occurrence.
Generally, because a sinusoidal AC waveform is mainly used for a power line of a power grid, when a circuit breaker is suddenly opened, a switching surge such as an arc caused by transients may occur on the circuit breaker. Such opening and closing surge may shorten the lifecycle of the circuit breaker by degrading its performance. In addition, when the time goes by, the circuit breaker becomes obsolete, it is impossible to accurately open and close the circuit breaker. Therefore, a lot of studies on technology of controlling opening and closing of a circuit breaker have been made.
For example, Korean Patent Laid-Open Publication No. 10-2005-0117193 proposes a device for controlling opening and closing a circuit breaker to which a power semiconductor device is applied in order to control opening and closing the circuit breaker in any circumstances, comprising a means for driving the circuit breaker composed of a FET driving unit and a relay driving unit with a fast switching speed in parallel to minimize delay of operating time of an opening and closing controller, thereby causing rapid control of the opening and closing the circuit breaker and to allow the relay driving unit connected in parallel to operate the circuit breaker upon failure in the FET driving unit.
However, even in this case, it is impossible to prevent the noise impact over the zero-crossing detect. Therefore, it may delay controlling the opening and closing of the circuit breaker or cause a malfunction thereof.
It is an object of the present invention to provide a method of, and a device for, controlling opening and closing a circuit breaker by minimizing noise impact over a zero-crossing detect.
It is the other object of the present invention to provide a method of, and a device for, controlling a circuit breaker that protects phase modifying equipment by performing a reliable operation without malfunction even in a poor environment of a substation while operating the circuit breaker without any delay by minimizing noise impact over zero-crossing detect based on an integral over a period.
The drawings attached below to explain example embodiments of the present invention are only part of example embodiments of the present invention and other drawings may be obtained based on the drawings without inventive work for those skilled in the art:
Explanation of detailed example embodiments to execute the present invention is made by referring to attached drawings.
The present invention may make alternations and have several example embodiments. Therefore, specific example embodiments will be exemplified in drawings and used for detailed explanation. It may be understood that this is not intended to limit the present invention to the specific example embodiments and include all modifications, equivalents or alternatives included in the spirit and technical scope of the present invention.
A method of, and a device for, controlling opening and closing of a circuit breaker in accordance with the present invention are explained below in details by referring to attached drawings.
By referring to
By referring to
Herein, the reference as a specific positive value exceeding zero may be determined to be properly set depending on an environment and a situation of installing the circuit breaker such as amplitude of the signal or degree of noise. Besides, the set phase may be determined as a value between 0 degree and 360 degrees.
Meanwhile, it is desirable that the method of controlling the opening and closing of the circuit breaker in the present invention is applied to a circuit breaker for frequent phase modifying equipment switching that cuts off a voltage level of at least 1 kV.
In case of the conventional method of controlling the opening and closing of the circuit breaker, at the step of detecting the change in the sign as S120, the circuit breaker detects a zero-crossing regarding an inputted signal and at the step of opening and closing the circuit breaker as S160, the circuit breaker is controlled to be opened and closed at a set phase but at the time, when the zero-crossing occurs due to noise, a delay in controlling an opening and closing device occurs over at least one period because setting a zero-crossing reference is performed again at the step of setting the zero-crossing reference as S130.
Accordingly, when the absolute value of an integral over a period does not exceed a reference value at a step of comparing the integral over a period as $140 by making the integral based on the zero-crossing to minimize such delay in the present invention, to minimize such delay, it may be ignored by being considered as the zero-crossing by noise and the circuit breaker may be opened and closed at a set phase without any noise impact.
At the time, as explained above, the reference as a specific positive value exceeding zero may be determined to be properly set depending on an environment and a situation of installing the circuit breaker such as amplitude of the signal or degree of noise.
But, as shown in
Therefore, in the present invention, if the abnormal integral waveform 270 does not exceed a reference 230, i.e., if the abnormal value of the integral over a period by integrating the signal over one period based on the zero-crossing does not exceed the reference 230, the abnormal zero-crossing 260 is determined as zero-crossing caused by noise, thereby being ignored. After that, the opening and closing of the circuit breaker is controlled based on the normal zero-crossing 250.
The method of controlling the opening and closing of the circuit breaker in the present invention may allow the opening and closing of the circuit breaker to be controlled without any delay over a period.
As shown in
According to the conventional method, when an abnormal zero-crossing 360 is detected, a next zero-crossing 370 is detected again. As seen in
On the other hand, as seen in
Accordingly, the present invention may control the circuit breaker without any delay even though the abnormal zero-crossing 360 caused by noise occurs.
As seen in
As explained above, herein, the reference as a specific positive value exceeding zero may be determined to be properly set depending on an environment and a situation of installing the circuit breaker such as amplitude of the signal or degree of noise and the set phase may be determined as a value between 0 degree and 360 degrees. In addition, it is desirable that the device for controlling opening and closing of the circuit breaker in the present invention is applied to a circuit breaker for frequent phase modifying equipment switching that cuts off a voltage level of at least 1 kV.
The device for controlling opening and closing of the circuit breaker in the present invention first detects zero-crossing from a sign of the signal through the zero-crossing detecting unit 430 for detecting with respect to the inputted signal through the signal inputting unit 410.
After that, when integration is made based on the zero-crossing and the absolute value of an integral over one period does not exceed a reference value, the control unit 440 controls the opening and closing of the circuit breaker at a set phase through the unit 420 for opening and closing the circuit breaker.
Accordingly, the device for controlling opening and closing of the circuit breaker in the present invention may control the circuit breaker without any delay even though an abnormal zero-crossing caused by noise occurs.
As seen above, while being capable of operating the circuit breaker without any delay by minimizing noise impact upon zero-crossing detect based on the integral over a period, the method of, and the device for, controlling opening and closing the circuit breaker in accordance with the present invention may protect phase modifying equipment by performing a reliable operation without malfunction even in the poor environment of a substation.
The method of, and the device for, controlling opening and closing the circuit breaker in accordance with the present invention may control the circuit breaker by minimizing the noise impact upon the zero-crossing detect.
Furthermore, the present invention has an effect of protecting phase modifying equipment by performing a reliable operation without malfunction even in the poor environment of a substation while being capable of operating the circuit breaker without any delay by minimizing noise impact upon zero-crossing detect based on the integral over a period.
What has been explained above includes at least one example embodiment. Of course, it cannot be recognized that all possible combinations of components or methods for the purpose of explaining the aforementioned example embodiments but it can be perceived that those skilled in the art may make a lot of additions and replacements of various example embodiments. Accordingly, the explained example embodiments include all alternatives, modifications, and changes without departing from the spirit and scope of the invention as defined in the following claims.
The present invention which relates to a method of, and a device for, controlling opening and closing of a circuit breaker is available in a field of circuit breaker.
Number | Date | Country | Kind |
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10-2015-0190257 | Dec 2015 | KR | national |
Filing Document | Filing Date | Country | Kind |
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PCT/KR2016/015211 | 12/23/2016 | WO | 00 |