KR20100031050A - Circuit breaker - Google Patents

Abstract

PURPOSE: A circuit breaker is provided to controls arc generation at a high current region by reducing calculation and determination time of a microcomputer. CONSTITUTION: A first power source current transformers(3a,3b,3c) are arranged in a wiring circuit(1). A first rectifier circuit(5) rectifies a second output current from the first power source current transformer. A microcomputer(9) is arranged in a discrete circuit. The microcomputer controls the inverse time operation of the circuit breaker. A second isolation device executes the isolation operation of the circuit breaker until the arc is generated between contact points for making and breaking of the circuit breaker when a load current exceeds the maximum instantaneous current value of the battery circuit breaker.

Description

Circuit breaker {CIRCUIT BREAKER}

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a circuit breaker which detects an accidental current and protects an electric circuit, and more particularly, to detecting overcurrent of a circuit breaker and speeding up the disconnection operation.

In the conventional circuit breaker, the overcurrent is detected by the constant voltage circuit formed by rectifying the current to be the secondary output of the current transformer disposed in each phase as the constant voltage energy source for operating the separation circuit, It is known to perform calculation and determination by a microcomputer constituting a circuit, conducting a separation operation of a circuit breaker inserted in each phase by conducting a separation coil in accordance with a predetermined anti-time characteristic (for example, a patent document) See 1)

Patent Document 1: Japanese Patent Application Laid-Open No. 2001-165964

However, in the method of operating the breaker circuit of the breaker by the microcomputer as described above, there is no problem in the operation area according to the predetermined inverse time characteristic, but, for example, when the short-circuit large current exceeding the maximum instantaneous current setting value flows. For example, about 20 ms is required until the disconnection operation is started and the blocking operation is completed. Specifically, for example, the operation / determination time including the initial setting time of the microcomputer and the operation of the trigger circuit, for example, about 1 ms or less until a voltage source is formed by the constant voltage circuit after the short circuit occurs, for example, about 10 ms, The operating time of the separation mechanism is, for example, about 15 ms and a total of about 26 ms is required.

For this reason, when a short-circuit large current exceeding the maximum instantaneous current set value flows, a large current flows through the breaker's open / close contact until the breaker operation is started and the breaker operation is completed, and an arc is generated between the contacts for a long time. It has been found that this occurs until the contact is consumed and the current carrying performance is impaired. In addition, since more short-circuit currents flow due to the arcing between the contacts, there is a possibility that welding occurs between the two contacts.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems. By shortening the time until breaker disconnection operation starts in the event of a large current, the contact loss and welding of the contact are eliminated, and the energization function is good for a long time and the resiliency is high. It is an object to provide a circuit breaker.

The circuit breaker according to the present invention uses a constant voltage circuit formed by rectifying a secondary current of a power supply current transformer disposed in a wiring converter as a constant voltage energy source for operating a separation circuit, and the separation circuit includes the wiring circuit. And a microcomputer that performs calculation and determination so as to obtain a predetermined inverse time operation characteristic in accordance with the flowing load current, and performs the separation operation of the circuit breaker by the first separation mechanism in accordance with the inverse time operation characteristic. When the maximum instantaneous current setting value of the circuit breaker is exceeded, a second separation mechanism for separating the circuit breaker is provided until a call is generated between the opening and closing contacts of the circuit breaker, thereby separating the circuit breaker by the second separation mechanism. It is characterized in that the operation is configured to be faster than the separation operation by the first separation mechanism. .

According to the present invention, when the large current exceeding the maximum instantaneous current set value and there is a possibility that a call occurs between the contacts of the circuit breaker flows, a large current flows because a second separation mechanism for immediately disconnecting the circuit breaker is provided. Since the time until the disconnection operation of the breaker is started is shortened, and the disconnection operation until the call between the two contacts can be completed, the contact of the contact is eliminated and the circuit breaker with good current carrying performance can be obtained. Have

Embodiment 1.

EMBODIMENT OF THE INVENTION Hereinafter, Embodiment 1 of this invention is described with reference to FIGS. FIG. 1 is a circuit diagram illustrating a circuit breaker in Embodiment 1 of the present invention, FIG. 2 is a diagram illustrating a separation operation characteristic of the circuit breaker according to the present invention, and FIG. 3 is a cross-sectional view of the second separation mechanism. In Fig. 1, 1 is a wiring converter, 2 is an open / close contact of a circuit breaker, 3a, 3b, and 3c are first power supply current transformers disposed in the respective converters 1, 4a, 4b, and 4c are current detection coils, and 5 is First rectifier circuit for rectifying the secondary output current from the first power supply current transformer (3a, 3b, 3c), 6 is a constant voltage to form a stabilized constant voltage source receiving the rectified output of the first rectifier circuit (5) Circuit 7 is a control circuit which uses the output of the constant voltage circuit 6 as a voltage source and uses the secondary currents of the current detection coils 4a, 4b, and 4c as input signals, and an A / D conversion circuit (not shown); A dedicated IC 8 made of an integration circuit or the like, and a microcomputer 9 incorporating a characteristic for controlling the inverse time operation of the circuit breaker and performing a predetermined calculation and determination.

Although not shown in the microcomputer 9, as described in Patent Document 1, a long time characteristic detection unit for detecting up to 115% of the rated current to a short time current set value, and a short time It includes a short time characteristic detection unit for detecting current set value to instantaneous current set value, and instantaneous characteristic detection unit for detecting abnormal instantaneous current set value, and controls the relationship between current value and separation time by different exponential characteristics. Doing. In addition, 10 is a trigger circuit such as a thyristor or the like which operates as an output signal of the microcomputer 9, and 11 is a first separation coil 12a which is excited by conduction of the trigger circuit 10. 12a 12b, 12c are second power supply current transformers disposed in the respective converters 1, 13 are second rectifier circuits for rectifying secondary output currents from the second power supply current transformers 12a, 12b, and 12c. Is a second separation coil that is excited by the output of the second rectifier circuit 13.

Next, the disconnection operation of the circuit breaker according to the first embodiment will be described according to the disconnection operation characteristic diagram of FIG. 2. As shown in FIG. 2, the current having the rated current or more flows through the wiring converter 1, and has an inverse time characteristic in which the operating time of the opening / closing contact 2 of the circuit breaker is shortened as the magnitude thereof becomes larger. The long-time operating range from 115% to the short-time current set value, and the short-time current set value to the instantaneous current set value (maximum) are defined as the instantaneous operating range and the instantaneous current set value. In addition, in FIG. 2, the specific electric current value which assumed the disconnection | operation operation | movement of a specific circuit breaker (for example, 2000 A of rated currents) is shown by ratio with the rated current, and this characteristic value is changed when the rated current of a circuit breaker changes. Will also change.

When a load current flows in the wiring converter 1 now, the secondary output currents of the first power supply current transformers 3a, 3b, and 3c are rectified in the first rectifying circuit 5 and stabilized in the constant voltage circuit 6, and the control circuit It becomes a power source for operating (7). On the other hand, the magnitude of the current flowing through the wiring converter 1 is detected by the current detection coils 4a, 4b, and 4c, and monitored by the microcomputer 9 through the dedicated IC 8 of the control circuit 7. . The microcomputer 9 determines whether the long time operation region, the short time operation region, or the instantaneous operation region of FIG. 2 is determined according to the magnitude of the load current flowing in the wiring converter 1, and the respective inverse time characteristics are determined. Therefore, a calculation result is output, the trigger circuit 10 which consists of a thyristor is operated, the 1st isolation coil 11 is excited, and a disconnection operation of a circuit breaker is performed. As described above, it takes about 20 ms to complete the operation by the first separation mechanism.

In addition, in the range A until the load current exceeds the maximum instantaneous current set value and reaches a current which may cause the breaker body to call, the operation by the second separation mechanism is performed by the first separation mechanism. It is initiated prior to operation.

That is, when the area to be called by the circuit breaker main body of FIG. 2 is set to B, in the present invention, the maximum instantaneous current set value X (for example, about 16 times the rated current) is exceeded, and a call is made between the contacts of the circuit breaker main body. When the overcurrent up to the generated current Y (for example, about 30 times the rated current) flows in the wiring converter 1, the second power supply current transformers 12a, 12b, 12c are discharged from the second rectifier circuit 13 through the second rectifier circuit 13; The two separation coils 14 are excited to perform the opening operation of the circuit breaker earlier than the operation of the first separation coils 11. The operating current of the second separation coil at this time is indicated by the point Z in FIG. 2, and the trip operation is performed until the circuit breaker main body is called with a value of about 15 times the rated current, for example.

Therefore, in the case where the second separation mechanism does not exist and only the first separation mechanism is required as described above until the operation is completed, for example, about 20 kW is required. However, when the second separation mechanism is used in combination, the microcomputer Since it does not pass through the control circuit 7 including the (9) or the trigger circuit 10 consisting of the thyristor, the time until the completion of the operation is the calculation / decision time including the initial setting of the microcomputer 9 (for example, For example, about 10 kPa), for example about 10 kPa. In addition, the exciting time point of the 2nd separating coil 14 is adjusted so that upper-left Z point may come from the maximum instantaneous current setting value X to the current Y which call | occur | produces between the contacts of a circuit breaker main body (section A).

3 is a schematic configuration diagram of the second separation mechanism, which will be described together with the adjustment method of the excitation timing of the second separation coil 14. In the figure, 14 is a coil wound around the core part of bobbin 21, and corresponds to the 2nd separating coil 14 of FIG. In the bobbin 21, the fixed iron core 22 and the movable iron core 23 are disposed to face each other, and a predetermined gap 27 is formed between the fixed iron core 22 and the movable iron core 23. There is a return spring 24 to hold and place. The yoke 25 is for magnetically coupling the magnetic flux generated in the coil 14 through the fixed iron core 22 and the movable iron core 23, and the shaft 26 is the maximum instantaneous current. The open / close contact 2 of the breaker is operated (not shown) when an overcurrent until the set value is exceeded and a call occurs between the contacts of the breaker main body flows through the wiring converter 1.

As mentioned above, the 2nd separation mechanism is comprised from the coil 14, the fixed iron core 22, the movable iron core 23, the return spring 24, etc., and is movable iron core 23 by the spring force of the return spring 24. As shown in FIG. ) And the fixed iron core 22 are conductive in a direction away from each other as described above. When the load current exceeds the rated current and reaches a maximum instantaneous current set value X, the magnetic force of the coil 14 is set smaller than the spring load of the return spring 24, and the movable iron core 23 Since the silver is not adsorbed by the fixed iron core 22, the breaker does not trigger.

However, when a large current exceeding the maximum instantaneous current set value X flows, the magnetic force of the coil 14 is set to exceed the spring load, and the movable iron core 23 is attracted to the fixed iron core 22 and the shaft 26 ) Protrudes to operate the second separation mechanism.

The spring load and the coil of the return spring 24 so that the operating point at which the movable iron core 23 is attracted to the fixed iron core 22 exceeds the maximum instantaneous current set value X and is less than a current which causes a call between the contacts of the breaker. The magnetomotive force of (14) is adjusted and set.

As described above, the first separation mechanism operates precisely at a current below the maximum instantaneous current set value, and operates the second separation mechanism below a current exceeding the maximum instantaneous current set value and a call is generated between the contacts of the circuit breaker. Since the calculation and determination time by the control circuit including the microcomputer can be shortened, the call in the large current region can be suppressed.

Embodiment 2.

4 is a schematic diagram of a circuit breaker of the circuit breaker according to the second embodiment of the present invention, and the same reference numerals are given to the same or corresponding parts as those in FIG. Embodiment 2 of the present invention omits the second power supply current transformers 12a, 12b, 12c and the second rectifier circuit 13 of the first embodiment, and replaces the second separation coil 14 with the rectifier circuit 5 and the constant voltage. It is inserted between the circuits 6. By doing in this way, compared with the thing of Embodiment 1, since a set of a power supply current transformer and a rectifier circuit may respectively be sufficient, a circuit structure becomes simple.

Embodiment 3.

Fig. 5 is a circuit diagram of a separation circuit of the circuit breaker according to the third embodiment of the present invention. The same code | symbol is attached | subjected to the part same as that of FIG. 1, and it demonstrates only a part different from FIG. Embodiment 3 of the present invention inserts the second power supply current transformers 12a, 12b, 12c and the second rectifier circuit 13 of the first embodiment into secondary converters of the first power supply current transformers 3a, 3b, 3c. It is. By doing in this way, since the external shape and the magnitude | size of an electric current which can penetrate compared with the thing of Embodiment 1 can also be made small, the 2nd power supply current transformers 12a, 12b, 12c, and a rectifier circuit can be comprised with a small capacity | capacitance. Can be.

Embodiment 4.

Fig. 6 is a circuit diagram of a separation circuit of the circuit breaker according to the fourth embodiment of the present invention. The same code | symbol is attached | subjected to the part same as that of FIG. 1, and it demonstrates only a part different from FIG. In the fourth embodiment of the present invention, the variable resistor 15 is inserted in parallel with the second separation coil 14 of the first embodiment.

By doing in this way, since the electric current supplied to the said 2nd separating coil 14 from the 2nd power supply current transformer 12a, 12b, 12c can be classified, it is necessary to adjust the value of this variable resistor 15. FIG. This makes it possible to set the magnitude of the short-circuit current at which the second separation coil 14 operates in accordance with the rated current of the breaker or the like.

1 is a circuit diagram of a separation circuit of a circuit breaker according to the first embodiment of the present invention.

2 is a diagram showing an example of the disconnection operation characteristic of the circuit breaker of the present invention.

3 is a schematic cross-sectional view of the second separation mechanism.

4 is a circuit diagram of a separation circuit of the circuit breaker according to the second embodiment of the present invention.

Fig. 5 is a circuit diagram of a separation circuit of the circuit breaker according to the third embodiment of the present invention.

Fig. 6 is a circuit diagram of a separation circuit of the circuit breaker according to the fourth embodiment of the present invention.

Explanation of the sign

1 wiring converter,

2 switching contact of breaker,

3a, 3b, 3c first power supply current transformer,

4a, 4b, 4c current detection coil,

5 first rectifying circuit,

6 constant voltage circuit,

7 control circuit,

8 dedicated IC,

9 microcomputer

9, 10 trigger circuits,

11 first separating coil,

12a, 12b, 12c second power supply current transformer,

13 second rectifier circuit,

14 second disconnect circuit,

15 variable resistor,

21 bobbins,

22 fixed iron core,

23 operation iron core,

24 return spring,

25 York,

26 shafts.

Claims (6)

A constant voltage circuit formed by rectifying a secondary current of a power supply current transformer disposed in a wiring converter is used as a constant voltage energy source for operating a separation circuit, and the separation circuit has a load current flowing in the wiring circuit. A microcomputer is provided for performing calculation and determination so as to obtain a predetermined anti-time operation characteristic, and in performing the operation of disconnecting the breaker by the first separation mechanism in accordance with the anti-time operation characteristic, the load current When the maximum instantaneous current setting value of the circuit breaker is exceeded, a second separation mechanism for separating the circuit breaker is provided until a call is generated between the opening and closing contacts of the circuit breaker. A circuit breaker characterized in that the disconnection operation of the circuit breaker is faster than the separation operation by the first separation mechanism. The method according to claim 1, The second separation mechanism is composed of at least a separation coil, a fixed iron core, a movable iron core and a spring, When the load current exceeds the rated current of the circuit breaker and reaches a maximum instantaneous current set value, the magnetic force of the separation coil is set smaller than the spring load of the spring, When the load current exceeds the maximum instantaneous current set value of the circuit breaker, the circuit breaker is set so that the magnetic force of the separation coil exceeds the spring load until a call occurs between the opening and closing contact of the circuit breaker . The method according to claim 1 or 2, A first rectifying circuit for supplying a rectified voltage to the first separation coil by a first power supply current transformer disposed in the wiring converter; And a second rectifying circuit for supplying a rectified voltage to the second separation coil by a second power supply current transformer disposed in the wiring converter. The method according to claim 1 or 2, And a single rectifier circuit for supplying a rectified voltage to the first separation coil and the second separation coil by a power supply current transformer disposed in the wiring converter. The method according to claim 1 or 2, A first rectifying circuit for supplying a rectified voltage to the first separation coil by a first power supply current transformer disposed in the wiring converter; And a second rectifying circuit for supplying a rectified voltage to the second separation coil by a second power supply current transformer disposed on the secondary side of the first power supply current transformer. The method according to claim 3, A variable resistor is connected in parallel to said second separating coil.

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