KR100196016B1 - Circuit breaker - Google Patents

Abstract

The circuit breaker includes a current detecting means for detecting a current of a converter conductor, a tripping device for opening and closing a contact in the event of an abnormal current, a harmonic detecting means for detecting harmonic components based on the output of the current detecting means, and the harmonic detecting means. And a comparison means for generating an output when the output of the harmonic detection means exceeds the set value by comparing the output of the output with the set value, and an alarm output means for generating an alarm output based on the output of the comparison means. When the predetermined value of the detected harmonics is exceeded, the output of the comparing means is first supplied to the alarm output means, thereby protecting the device from the effects of the breakout circuit and harmonics of the system.

Description

Circuit breaker

1 is a block diagram of an electrical circuit of a circuit breaker of an embodiment of the present invention.

2 is a cross-sectional view of a circuit breaker of the embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

11, 12, 13, 14: Current transformer 18: MPU

19: characteristic setting unit 20: alarm display unit

21: tripper 22: alarm output circuit

TECHNICAL FIELD The present invention relates to a circuit breaker having an alarm function, and more particularly to a circuit breaker suitable for detecting an alarm by detecting harmonic currents.

In recent years, a large amount of harmonic currents have been generated by OA devices and inverter control devices, and this has adversely affected other electrical equipment and devices. As a countermeasure against such an adverse effect, various filters and the like have been taken. However, the conventional harmonic measurement and analysis for countermeasures have been to display and record the so-called measuring instrument level, i. For the analysis and countermeasures about harmonics, for example, "harmonic countermeasures (1)", old house, building equipment company, '94 -8, "harmonic countermeasures (2)", old house, building equipment company, "94-11," "Investigation of occurrence cases of harmonic disturbance in existing buildings", 關 本 關, Building equipment company, '92 -5.

Since the prior art only displays and records, long-term measurement and recording are necessary to grasp the influence of the harmonics that change in the operating state of the load, and post-human involvement is necessary for countermeasures. Moreover, since the said prior art is provided separately from the breaker in a general switchboard and a power switchboard, the installation space was a problem and it was impossible to receive in a board | substrate.

The present invention has been made in view of the above problems, and an object thereof is to provide a circuit breaker having a function of detecting an effect of harmonics and generating an alarm.

In order to achieve the above object, the present invention includes a converter conductor connected to a water distribution system having an opening and closing contact, a current detecting means for detecting a current of the converter conductor, and a tripping device for opening the opening and closing contact in the event of an abnormal current. In the circuit breaker, a harmonic detection means for detecting a harmonic component based on the output of the current detection means, and an output is generated when the output of the harmonic detection means exceeds the set value by comparing the output of the harmonic detection means with a set value. And an alarm output means for generating an alarm output based on the output of the comparison means.

The current detected by the current detecting means is converted into a crest factor (hereinafter referred to as CF), that is, an effective value / peak value, or developed into an n-th harmonic in the calculation means of the next stage. When the level set by the negative is exceeded, an alarm or interruption is issued.

According to the present invention, when the harmonic current exceeds a predetermined value, an alarm can be issued prior to the interruption, so that the device can be protected from accidental interruption and the effect.

Embodiments of the present invention will be described with reference to FIGS. 1 and 2.

This embodiment applies the present invention to a four-pole breaker having a neutral wire.

1 is a circuit block diagram of this embodiment, and FIG. 2 is a structural diagram of a circuit breaker having this circuit. The circuit breaker of the present embodiment has the power supply side terminals 1, 2, 3, 4 in the housing 42 made up of the case 41 and the cover 43, and the load side terminals 5, 6, 7, 8 corresponding to each of them. Between the power supply terminal (1) and the load side terminal (5), between the power supply terminal (2) and the load side terminal (6), and between the power supply terminal (3) and the load side terminal (7). U-shaped conductive conductors 24U, V-shaped conductive conductors 25V, W-shaped conductive conductors 25W, and neutral-shaped conductive conductors 25N are provided between the power supply terminal 4 and the load terminal 8, respectively. do. These converter conductors are provided with open / close contacts 25U, 25W, 25V, and 25N, respectively. The opening and closing contacts 25U, 25W, 25V, and 25N are normally opened and closed by the operation of the operation handle 44, and the tripper 21 is used when there are defects in the electric current such as overcurrent, current unbalance, and generation of harmonics. It is opened by the tripping operation. As such a shutoff mechanism, you may use what was disclosed by Unexamined-Japanese-Patent No. 61-151945, for example. Each converter conductor 24U, 24W, 24V, 24N is provided with current transformers 11, 12, 13, 14 as current detection means. 2 shows a V-shaped cross section in which the handle 44 and the blocking mechanism are installed.

The outputs of the current transformers 11 to 14 are supplied to the power supply circuit 16 and the signal detection circuit 17 through the rectifier 15. The power supply circuit 16 constant-voltages the output of the rectifier circuit 15 to output the signal detection circuit 17, the MPU 18 as a calculation means, the characteristic setting unit 19, the alarm display unit 20, and the tripper 21. To the alarm output circuit 22 as the alarm output.

The signal detection circuit 17 converts the outputs of the rectifiers 11 to 14 rectified through the rectifier 15 into voltage levels and outputs them to the MPU 18. The detection of overcurrent uses the output of the current transformers 11, 12, 13, the detection of current unbalance uses the output of the current transformer 14, and the detection of harmonics uses the current transformers 11, 12, 13, 14. . The MPU 18 is each composed of an A / D converter 18A, an I / O 18C, an I / O 18D, and an I / O 18E connected to the CPU 18B. A tripper 21 is connected to the I / O 18C, a property setting unit 19 and an alarm display unit 20 to the I / D 18D, and an alarm output 22 to the I / O 18E, respectively. . The characteristic setting unit 19 sets the output level of the cutoff signal supplied to the tripper 21. The alarm output 22 includes a contact relay, a photo coupler, a photo MOS relay, and the like, and an optical coupling element. The alarm output 22 includes an indicator light, a sound or voice generating device, a CRT, a liquid crystal, or an LED through an output terminal 30. Supply output to alarm devices such as displays.

The rectifier circuit 15, the power supply circuit 16, the signal detection circuit 17, the MPU 18, the characteristic setting unit 19, the alarm display 20, and the alarm output 22 are placed on the circuit board 46. It is assembled, it is provided in the inside of the cover 43 in the upper side of the housing 42, and it is arrange | positioned so that the indication of the alarm display 20 may be read through the transparent part of the cover 43. As shown in FIG. The output terminal 30 is a connector in this embodiment, and is comprised so that an output may be taken out from the surface of the cover 43. As shown in FIG.

The converter conductors 24U, 24W, 24V, 24N are connected to the water distribution system, and the current transformers 11, 12, 13, 14 detect current flowing through each converter conductor.

The MPU 18 calculates harmonic components from the detection outputs of the current transformers 11, 12, 13, and 14, and generates an alarm output when the system's harmonics exceed the first set value, which is greater than the first set value. When the second set value is exceeded, the shut-off operation is programmed. This interruption operation has a time characteristic that matches the harmonic content of the load.

The first and second set values may be C.F., the value of the nth harmonic or the value of the neutral current.

The MPU 18 is based on the magnitude of the harmonic components with respect to the detection outputs of the current transformers 11, 12, 13, and 14 based on the magnitude of the harmonic components, specifically, the n-th harmonic content rate by calculation of the CF or Fourier expansion. Is performed to detect the presence or absence of harmonics. C.F. And the calculation itself of the nth harmonic content ratio are well known operations, and thus description thereof is omitted. The MPU 18 compares the arithmetic result of the harmonics with a preset value in the characteristic setting unit 19, and when the setting value is exceeded, displays an alarm by the alarm display unit 20 and at the alarm output unit 22. Generate an alarm output. At this time, by setting a threshold value for whether to only alarm or even shut off according to the distortion of the current waveform as a second set value in advance, it is possible to select whether to only alarm or even shut off. In the case of the interruption, the interruption is performed after a predetermined time limit by the time characteristic that matches the harmonic content of the load. That is, in this embodiment, the MPU 18 has a function as a harmonic detection means and a comparison means.

According to this embodiment, a plurality of setting values are set, and C.F. Alternatively, by detecting the nth harmonic, an alarm can be issued before the interruption, thereby preventing unexpected unexpected interruption (hereinafter abrupt interruption), and also separating or harmonics from the circuit of the device affected by the harmonics when an alarm occurs. Damage to the device can be prevented by separating the circuit from the device which is weak and preventing adverse effects of harmonics.

In addition, by comparing the current of the neutral conductor conductor 24N with the value set by the characteristic setting unit 19, it is possible to eliminate the adverse effect of the increase in the neutral current due to harmonics on the device.

According to the present invention, when the harmonic current exceeds a predetermined value, an alarm can be given in preference to the interruption, so that an unexpected interruption can be avoided. The protection of equipment from harmonic effects can be avoided.

Claims (4)

A converter conductor connected to a water distribution system having an open / close contact, a current detecting means for detecting a current of the converter conductor, and a tripper for opening the open / close contact in case of an abnormal current A circuit breaker comprising: harmonic detection means for detecting harmonic components based on an output to said current detection means; Comparison means for generating an output when the output of the harmonic detection means exceeds the set value by comparing the output of the harmonic detection means with a set value; And alarm output means for generating an alarm output based on the output of the comparison means, wherein the harmonic detection means and the comparison means are composed of arithmetic means, and the comparison means sets the output of the harmonic detection means to a first set value. And the comparison means supplying an output to the alarm output means when the output of the harmonic detection means exceeds the first set value, compared to a second set value larger than the first set value. And when the set value is exceeded, supplying an output to the trip device to perform a cutoff operation with a time-limiting characteristic in accordance with the harmonic content of the load. A circuit breaker comprising a converter conductor connected to a water distribution system having an open / close contact, a current detecting means for detecting a current of the converter conductor, and a trip device for opening the open / close contact in case of an abnormality of the current, wherein the current detecting means is provided. Harmonic detection means for detecting harmonic components based on an output of the harmonic components; Comparison means for generating an output when the output of the harmonic detection means exceeds the set value by comparing the output of the harmonic detection means with a set value; And alarm output means for generating an alarm output based on the output of the comparison means, wherein the harmonic detection means and the comparison means are constituted by calculation means, wherein the calculation means is a magnitude of harmonic components from the output of the current detection means. Calculating a quantity based on the quantity, and comparing the quantity with the set value to generate an output when the amount exceeds the set value. 3. A circuit breaker as claimed in claim 2, wherein the amount based on the magnitude of the harmonic component is a crest factor or a value of nth harmonic. The circuit breaker according to claim 2, wherein the amount based on the magnitude of the harmonic component is a value of a neutral current.