KR970001862Y1 - Overload detection device of breaker - Google Patents

Abstract

No content.

Description

Overload Detection Device of Low Voltage Circuit Breaker

1 is a configuration of the overload detection device of a conventional low voltage circuit breaker.

2 is a configuration of the overload detection device of the low-voltage circuit breaker of the present invention.

3 is a detailed view of a rectifying part and a current part in FIG. 2;

4 is a detailed view of the rectifying signal portion in FIG. 2;

* Explanation of symbols for main parts of the drawings

33: rectifying section 34: current section

35: integral circuit portion 36: filter portion

37: rectification signal unit 38: self-diagnosis detection unit

39: multiplexer 40: central processing unit

41: load current indicator 42: characteristic setting section

43: trigger section 44: overload alarm section

45: accident type operation part 46: communication circuit part

47: accident type indicator 48: operation circuit

49: breaker

The present invention relates to an overload detection device of a low voltage circuit breaker, and more particularly, to an overload detection device of a low voltage circuit breaker that is suitable for detecting the magnitude of a load current.

As shown in FIG. 1, the overload detector of the conventional low voltage circuit breaker includes a power current transformer 1 for obtaining a control power supply, a current detection current transformer 2 for detecting a load current, and the current detection current transformer 2. An integrating unit 5 for obtaining a voltage in phase equal to the load current detected by?), A rectifying signal unit 6 for full-wave rectifying the voltage integrated through the integrating unit 5, and flowing in each phase. A maximum phase selector 7 which selects the largest value among the currents, a peak value converter 9 which detects instantaneous and short-time characteristics from the output of the maximum phase selector 7, and an instantaneous moment according to the load characteristics. , The value set from the characteristic setting unit 10 and the effective value converting unit 9 for setting the short time and long time characteristics and outputting them to the instantaneous circuit unit 11, the short time circuit unit 12, and the long time circuit unit 13. Pre-alarm section 14 and current detecting current transformer 2 for alarming when an abnormal signal is generated by Ground fault circuit unit 15 for detecting a ground fault by detecting a ground fault current from the integration synthesizer 16 integrating and synthesizing the detected voltage, a trigger unit 19 and a trip coil TC for operating a circuit breaker; It consists of an operation circuit part 21 for operating a circuit for short-time, instantaneous operation, ground fault, etc. according to the operation state of the port coupler (PCI-PC4), and a control power supply part 22 for applying power to the operation circuit part 21. do.

Reference numeral 17 is a load current display lamp, and 18 is a current measurement output unit.

Looking at the conventional technology configured as described above are as follows.

When power is supplied from the power supply side to the load side, the load current of each phase detected by the current detecting current transformer 2 according to the magnitude of the load is in phase with the load current through the integrating unit 5. To get the voltage. At this time, the load current detected from the power transformer 1 is rectified through the rectifier 3 and the control power obtained through the current unit 4 is input to the trigger unit 19 and the overload alarm unit 20.

When the voltage integrated in the integrating unit 5 is a sine voltage and is rectified by the rectifying signal unit 6 so as to be suitable for a circuit operation and outputted to the maximum phase selector 7, detection of an accident current flows in the largest phase. Since the current needs to be detected, the maximum phase selector 7 detects the current flowing in the largest phase.

Then, the peak value converting section 8 detects the instantaneous and short time characteristics, and the effective value converting section 9 detects the long time characteristic and outputs it to the instantaneous and short time circuit sections 11 and 12 and the long time circuit section 13. When the overload is detected according to the characteristic value set by the characteristic setting unit 10, the trigger unit 19 and the trip coil TC are operated to cut off the circuit breaker 23 and the photo coupler PCI PC2. Through the short time / long time operation display 21-1 and the long time operation display 21-2, the short time and instantaneous operation states are displayed and the breaker is operated to shut off. In addition, when the pre-alarm unit 14 is operated for load protection, the pre-alarm state is operated in the photo coupler PC3 and the pre-alarm output unit 21-4 as in the above. If the ground fault occurs in comparison with the value set by the characteristic setting unit 10 in the ground circuit unit 15 with respect to the value integrated by the integral combining unit 16, the trigger unit 19 and the trip coil TC The circuit breaker 23 is cut off by operating the power supply control unit 22 to supply control power to each part of the status display unit 21.

The maximum phase current selected by the maximum phase selector 7 operates the breaker 23 by the output of the peak value converting section 8 which speeds up the response speed according to the type of accident.

However, in this technique, since the magnitude of the load current is not generally a sinusoidal wave, the peak value converting part which obtains a high-speed response (instantaneous and short-time functions) has a problem of lack of precision and a function of measuring the load current of each phase.

Therefore, in order to solve the conventional problems, the present invention converts the load current of each phase into an effective value so that a high speed response can be obtained, and the overload of the low voltage circuit breaker can detect the display of the load current and detect a malfunction state in the circuit part. The detection device is described as follows with reference to the drawings immersed in detail as follows.

2 is an overload detection device of the low voltage circuit breaker of the present invention. As shown therein, an integrating circuit section 35 for converting the load current detected by the current detecting current transformer 32 into the same phase and the integrating circuit section 35 are shown. Filter unit 36 to remove the harmonic components to the sine wave with respect to the integrated value through the through, and rectified signal unit 37 for full-wave rectification to simplify the effective value calculation with the sine voltage through the filter unit 36 And the load current and the characteristic setting of each phase can be simultaneously calculated according to the self-diagnosis detection unit 38 and the output values of the characteristic setting unit 42 and the rectifying signal unit 37, which enable checking the circuit state of each phase. A multiplexer 39, a central processing unit 40 which performs various calculations according to the input voltage, a rectifier 33 and a current unit 34 which operate the central processing unit 40 when the load current is above a certain value, Accident indicating the accident status of subordinate Send a variety of information to the type indicator 47, load current indicator 41 for measuring characteristics and load current, accident type operation section 45 for providing an output contact so that the status of the accident can be easily identified, and a computer. The communication circuit section 46, the operation circuit section 48 which operates each operation circuit by a long time, a ground fault, or abnormal temperature according to the output of the said accident type operation part 48, and the low voltage circuit breaker 49 in case of a load accident. Trigger unit 43 and the trip coil (TC) to block the) and the overload alarm unit 44 to sound an alarm in the overload state.

Referring to the operation and effects of the present invention configured as described above in detail.

When the load current flows from the power supply side to the load side, current is propagated by the power transformer 31 by the bridge diode BDI-BD4 in the detailed view of the rectifier 33 shown in FIG. 3, and the rectified voltage is applied to the load. The zener diodes Z5 and Z6 and the resistor R6 are detected at the base of the transistor Q2 according to the magnitude of the current. The voltage detected at the base is first applied to the inverting input terminal (-) of the operational amplifier OP1 and compared with the reference voltage of the non-inverting input terminal (+) to operate the transistor Q1, wherein the magnitude of the load current is excessive. In this case, the transistor Q1 is switched by the output of the operational amplifier OP1.

In this way, the load current can be easily controlled, and an excessive amount of heat can be immediately eliminated. When a small load current flows, the voltages of the transistors Q4-A6 and the zener diodes Z9-Z10 are inverted at the operational amplifier OP2. When the signal is input to (-), the reference voltage of the zener diode Z11 inputted to the non-inverting input terminal (+) is compared to operate the transistor Q7 and the transistor Q8 is turned off with the compared output. Do not cause + 12V, -l2V, + 5V), so there is no fear of logic malfunction.

The load current detected by the current detecting current transformer 32 is outputted by integrating in the integrating circuit section 35 so as to have the same phase as the load current, and that the harmonic component in the filter section 36 is close to the sine wave. To be filtered. The filtered sinusoidal voltage is calculated and amplified by the operational amplifiers OP10-OP16 in the rectifying signal unit 37 to calculate the effective value, and the amplification factor is multiplied by 1 times so that the multiplexer 39 can select according to the magnitude of the load current. We do it twice, four times, eight times. The self-diagnostic detector 38 detects a malfunction in the circuit from the rectified signal unit 37 and transmits the malfunction to the central processing unit 40.

Therefore, the central processing unit 40 compares the magnitude of the load current transmitted by the multiplexer 39 with the characteristic setting value by the characteristic setting unit 42 and calculates whether it is an overload or a normal state to determine an overload or an abnormal state. By controlling the accident type indicator 47 according to the accident type with the result determined in this way, the accident type is displayed by simultaneously operating the accident operation circuit of the accident operation circuit unit 48 through the accident type operation unit 45. Drives the user to easily check the accident type.

After determining the breaker accident state, the trigger unit 43 is driven according to each accident operation to block the breaker 49 with the trip coil T.C.

As described in detail above, the present invention has the effect of converting and calculating the load current of each phase to an effective value, and displaying the load current and detecting a malfunction state in the circuit.

Claims (1)

An integrating circuit section 35 for converting the load current detected by the current detecting current transformer 32 into the same phase, and a filter section for removing harmonic components with respect to the value integrated through the integrating circuit section 35 so as to be close to the sine wave. (36), a rectifying signal section (37) for full-wave rectification so that the effective value calculation can be simplified by the sine voltage through the filter section (36), and a self-diagnosis detection section (38) which enables inspection of the circuit state of each phase; The multiplexer 39 allows simultaneous operation of the load current and the characteristic setting of each phase according to the output values of the characteristic setting section 42 and the rectifying signal section 37, and the central processing section 40 which performs various calculations according to the input voltage. And a rectifier 33 and a current unit 34 for operating the central processing unit 40 when the load current is above a certain value, an accident type indicator 47 for displaying an accident state of the load, characteristic setting and load current. Load current indicator 41 for measuring In accordance with the output of the accident type operation unit 45 for providing an output contact, the communication circuit unit 46 for sending various kinds of information to the computer, and the output of the accident type operation unit 48, An operation circuit unit 48 for operating each operation circuit due to a ground fault or an abnormal temperature, a trigger unit 43 and a trip coil TC which allow the low voltage circuit breaker 49 to be cut off in the event of a load, and an alarm sound in an overload state Overload detection device of the low-voltage circuit breaker consisting of an overload alarm 44 to sound.