JP6140674B2 - Circuit breaker and power supply system - Google Patents

Description

The present invention relates to a circuit breaker and a power supply system.

  When connecting a transformer (transformer) to the load side of the circuit breaker, it is required to pay attention to the following points. That is, in the transformer, a large inrush current occurs when the power is turned on due to the relationship between the residual magnetic flux at the time of a power failure and the input phase at the time of power recovery. For this reason, there existed a problem that a high-order circuit breaker might carry out an unnecessary trip (for example, patent documents 1). Therefore, when using a transformer, for example, the following measures are taken to prevent unnecessary trips. (1) Use a breaker with a large rated current. This is because the set value of the trip current that instantaneously trips the circuit breaker is generally set according to the rated current of the circuit breaker. (2) There are measures such as using a reset breaker that mechanically and automatically turns the switch back on after an unnecessary trip. However, the measure (1) has a problem that when the circuit breaker is used as a contract breaker, the number of amperes increases, resulting in an increase in the electricity bill. In the measure (2), since the power is turned on again without specifying the cause of the trip, there is a risk that an electric device or the like may be defective in some cases.

Japanese Patent Laid-Open No. 10-136556

  As described above, when a transformer is connected to the output side of the circuit breaker, the circuit breaker may malfunction due to an inrush current when power is restored. In order to avoid a malfunction of the circuit breaker due to the inrush current, a circuit breaker having a larger capacity than necessary may be used. However, when malfunction is avoided by such a method, the short-circuit current cutoff characteristic may not be suitable. In general, in a configuration in which power is supplied to a load via a circuit breaker and a transformer, the value of the generated inrush power differs depending on the type of transformer and individual differences. For example, the reduction rate of the peak value of the inrush current flowing through the circuit breaker and the peak value of the inrush current for each cycle differ depending on the type of transformer and individual differences. Thus, when the value of the generated inrush power differs depending on the type of transformer and individual differences, the current value to be limited cannot be easily reduced to an appropriate current value.

  In general, the breaking characteristics of the circuit breaker are defined using the rated current value of the circuit breaker. Therefore, even when the specification of the transformer that hits the load is known, it is difficult to select a circuit breaker suitable for the transformer.

  In addition, when a circuit breaker having a large capacity is used for the above-described purpose, the power usage fee may be increased regardless of the actual amount of power used. That is, in order to prevent malfunction due to inrush current, it may be necessary to make a contract with an excessive rated current, and the power usage fee of the pay-per-use method may increase.

The present invention has been made in consideration of the above circumstances, it is to provide a circuit breaker and a power supply system can be prevented an unnecessary trip by without rush current by increasing the current rating of the circuit breaker Objective.

In order to solve the above problems, a circuit breaker according to the present invention includes a circuit breaker that cuts off a current flowing in a circuit that supplies power to a transformer, and a breaker that includes a control unit that cuts off the circuit breaker by electronic control. The control unit detects a current flowing through the circuit, and the current detection unit detects a current exceeding the rated current of the transformer multiplied by a predetermined first constant. A first cutoff control unit that cuts off a current flowing in the circuit by the circuit cutoff unit, and a current that exceeds a rated current of the circuit cutoff unit multiplied by a second constant smaller than the first constant multiple. And a circuit breaker corresponding to the operation state based on an operation state of the operation unit based on an operation state of the operation unit, and a second interruption control unit that interrupts a current flowing through the circuit by the circuit interruption unit based on a predetermined operating characteristic curve. Part And an initialization processing unit for determining a cutoff characteristic, and the information for determining the cutoff characteristic of the circuit cutoff unit includes information indicating a predetermined period during which the first cutoff control unit is disabled. It is characterized by.
In addition, the initialization processing unit of the circuit breaker according to the present invention determines the predetermined period corresponding to the transformer, and the first circuit break control unit starts energization to a circuit including the circuit circuit breaker. Until the predetermined period elapses, the current that flows through the circuit is not interrupted by the circuit interrupting unit, but the current exceeding the rated current of the transformer multiplied by a predetermined first constant after the predetermined period elapses. When the current detecting unit detects, the circuit interrupting unit interrupts the current flowing through the circuit.
In addition, the initialization processing unit of the circuit breaker according to the present invention includes the first processing unit according to an operation state of the operation unit until the predetermined period elapses after the circuit including the circuit breaker unit is energized. Set a constant.
Further, the initialization unit of the circuit breaker of the present invention determines whether or not it is necessary to change the breaking characteristics of the circuit breaker based on the operation state of the operation unit, and responds to the operation state based on the determination result. The first constant for determining the cutoff characteristic of the circuit cutoff unit is determined.

Another circuit breaker according to the present invention, the initialization processing unit, said transformer first so what the rated current and the first constant times becomes equal to or less than the maximum allowable current of the circuits blocking part of the A constant value is set.

  The power supply system of the present invention includes the circuit breaker and an electricity bill calculation unit that calculates an electricity usage fee according to the value of the rated current of the circuit breaker.

  Further, the interruption method of the present invention controls a circuit breaker including a circuit breaker that cuts off a current flowing in a circuit that supplies power to the transformer, and a controller that breaks the circuit breaker by electronic control. The control unit includes a current detection unit, a first cutoff control unit, a second cutoff control unit, and an initialization processing unit, and a current flowing through the circuit by the current detection unit. And detecting a current flowing through the circuit by the circuit interrupting unit when the current detecting unit detects a current exceeding the rated current of the transformer multiplied by a predetermined first constant by the first interrupting control unit. When the current detecting unit detects a current exceeding the rated current of the circuit interrupting unit multiplied by a second constant smaller than the first constant multiple by the second interrupting control unit, a predetermined operating characteristic curve Based on the circuit shielding Characterized by interrupting the flow of current in the circuit by parts.

  Further, the interruption program of the present invention controls a circuit breaker including a circuit interruption unit that interrupts a current flowing in a circuit that supplies power to the transformer, and a control unit that interrupts the circuit interruption unit by electronic control. The control unit includes a current detection unit that detects a current flowing through the circuit, a first cutoff control unit, a second cutoff control unit, and an initialization processing unit, and the first cutoff unit When the current detection unit detects a current exceeding the rated current of the transformer unit multiplied by a predetermined first constant by the control unit, the current that flows through the circuit is cut off by the circuit cut-off unit, and the second When the current detecting unit detects a current exceeding the rated current of the circuit interrupting unit multiplied by a second constant times smaller than the first constant multiple, the circuit interrupting unit based on a predetermined operating characteristic curve. By Characterized in that to execute a process of interrupting a current flowing through the circuit to the computer.

  In the present invention, when the current detection unit detects a current exceeding the rated current of the transformer multiplied by a predetermined first constant by the first cutoff control unit, the current flowing through the circuit is cut off by the circuit cutoff unit. Further, the second cutoff control unit cuts off the current flowing in the circuit by the circuit cutoff unit based on a predetermined operating characteristic curve. Therefore, it is possible to prevent the first breaking control unit from tripping due to the inrush current of the transformer without changing the breaking operation according to the rated current of the circuit breaking unit by the second breaking control unit. Unnecessary trips due to inrush current can be easily prevented without increasing the rated current.

It is a block diagram for demonstrating the structural example of the circuit breaker 1 of one Embodiment of this invention. It is explanatory drawing for demonstrating an example of the operating characteristic curve of the circuit breaker 1 shown in FIG. 3 is a flowchart for explaining an operation example of the microcomputer 18 shown in FIG. 1. 3 is a timing chart for explaining an operation example of the microcomputer 18 shown in FIG. 1. 6 is another timing chart for explaining an operation example of the microcomputer 18 shown in FIG. 1. It is a wave form chart for explaining an example of an inrush current of a transformer.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram for explaining a configuration example of an embodiment of the present invention. The circuit breaker 1 shown in FIG. 1 includes a control unit 10, a circuit breaker unit 11, a plurality of power supply side terminals 21, a plurality of load side terminals 22, a plurality of bus bars 23, and a plurality of bus bars 24. ing. Moreover, the circuit interruption | blocking part 11 is provided with the some contact 14 and the tripping coil 15, and interrupts | blocks the electric current which flows into a circuit. The control unit 10 includes a control circuit 12, a plurality of current transformers 13, and an operation unit 19, and blocks the circuit blocking unit 11 by electronic control. The control circuit 12 includes an output unit 16, an input unit 17, and a microcomputer 18. The power supply system 300 shown in FIG. 1 includes the circuit breaker 1, the watt-hour meter 2, and the electricity bill calculation unit 200. However, the power supply system 300 of the present embodiment may not include the watt-hour meter 2. Alternatively, the power supply system 300 may be configured to be included in the power dispatch distribution system 100, for example. The power dispatch / distribution system 100 is a system that performs power generation, power transmission, power transformation, and power distribution, and is operated by, for example, one or a plurality of business operators.

  In the example shown in FIG. 1, voltage lines L1 and L2 of a single-phase three-wire lead-in line and a neutral line N are connected to a plurality of power supply side terminals 21 of the circuit breaker 1 via a watt-hour meter 2. Yes. The voltage lines L1 and L2 and the neutral line N of the single-phase three-wire lead-in line are connected to a power line (not shown) included in the power dispatch system 100, for example. The electric power input through the plurality of power supply side terminals 21 is output from the plurality of load side terminals 22 through the plurality of bus bars 23, the plurality of contacts 14, and the plurality of bus bars 24. Further, in the plurality of load-side terminals 22, the primary-side terminals 31 of the single-phase lightning-resistant transformer 3 are connected to the terminals 22 to which the voltage lines L 1 and L 2 are connected via the circuit breaker 11. The terminal 22 to which the neutral wire N is connected is grounded.

  The lightning resistant transformer 3 is a transformer having a characteristic of attenuating a lightning surge output from the secondary side from about 1/100 to about 1/1000 when a lightning surge enters the primary side. The primary side terminal 31 and the secondary side terminal 33 of the lightning transformer 3 are insulated, and the primary side and the secondary side are separately grounded while being insulated from each other by separate grounding poles 32 and 34. A lightning arrester 35 is connected between the primary side terminal 31 and the other primary side terminal 31 and between each primary side terminal 31 and the ground electrode 32. A lightning arrester 35 is also connected between the two secondary terminals 33. The electrical device 4 is connected to the secondary side terminal 33 of the lightning resistant transformer 3.

  In the present embodiment, the primary side terminals of at least one transformer are connected to the plurality of load side terminals 22. That is, in the present embodiment, the circuit interrupting unit 11 interrupts the current flowing through the circuit that supplies power to the transformer. This transformer may be, for example, a single-phase transformer or a three-phase transformer.

  In the circuit breaker 11, the plurality of contacts 14 cooperate with the tripping coil 15 and a spring, electromagnet, toggle mechanism, etc. (not shown), and close the contacts 14 when a handle (not shown) is moved, for example. When the tripping coil 15 is excited, the contact 14 is opened. The trip coil 15 receives the current output from the output unit 16. The output unit 16 excites the tripping coil 15 when a predetermined signal is input from the microcomputer 18. Alternatively, the output unit 16 outputs a signal indicating that the overcurrent output from the input unit 17 is detected when a predetermined overcurrent is detected based on the output of the current transformer 13 at the input unit 17. The tripping coil 15 may be excited by inputting directly without going through 18.

  In the control unit 10, the plurality of current transformers 13 respectively convert the current flowing through the plurality of bus bars 24 at a predetermined current transformation ratio and output the converted current. The current output from the plurality of current transformers 13 is input to the input unit 17. The input unit 17 performs, for example, full-wave rectification on the alternating current output from the plurality of current transformers 13, further converts the current into a predetermined voltage value, and outputs the voltage.

  The operation unit 19 includes, for example, a push button switch for instructing an initialization process, an overcurrent threshold, a set time when an overcurrent is detected, and a rating of a transformer in which primary terminals are connected to a plurality of load terminals 22. Operating elements such as a dip switch and a rotary switch for setting the current value, the magnitude (multiplier) of the overcurrent threshold based on the rated current of the transformer, and the like are provided. The operation state of each operator of the operation unit 19 is input to the microcomputer 18 via the input unit 17.

  The microcomputer 18 includes a CPU (Central Processing Unit), a volatile and nonvolatile memory, a clock circuit, an A / D (Analog / Digital) converter, a digital input / output circuit, a timer circuit, and the like, which are not shown inside. A predetermined signal is input / output by executing a predetermined program stored in the nonvolatile memory. The microcomputer 18 detects the value of current flowing through each bus bar 24 based on the value of current output from each current transformer 13. Then, when an overcurrent or a short-circuit current is detected based on the acquired current value, the microcomputer 18 controls the output unit 16 to excite the tripping coil 15 and open each contact 14. In the present embodiment, the microcomputer 18 includes an initialization processing unit 181, a first cutoff control unit 182, and a second cutoff control unit 183 as main functions realized by executing a program. Yes. In the description of the operation of the microcomputer 18 to be described later, the initialization processing unit 181 and the first cutoff control unit 182 are the processing executed as the initialization processing unit 181, the first cutoff control unit 182, or the second cutoff control unit 183. Alternatively, the second cutoff control unit 183 will be described as an operation subject, and other processing will be described using the microcomputer 18 as an operation subject.

  The initialization processing unit 181 performs processing for initializing the interrupting characteristics of the circuit breaker 1 so that the interrupting characteristics of the circuit breaker 1 become the interrupting characteristics corresponding to the characteristics of a predetermined transformer (in this case, the lightning resistant transformer 3). . The first cutoff control unit 182 shuts down the circuit when the current transformer 13 detects a current larger than a predetermined first threshold after a predetermined first period has elapsed since the circuit including the circuit cutoff unit 11 is turned on. The section 11 performs a process of cutting off the current flowing through the circuit. When the current transformer 13 detects a current that is smaller than the first threshold and larger than the rated current of the circuit breaker 11, the second break controller 183 is configured to shut off the circuit based on a predetermined operating characteristic curve by the circuit breaker 11. I do.

  In the present embodiment, the breaking characteristics of the circuit breaker 1 initialized by the initialization processing unit 181 are the operating characteristic curve of the circuit breaker 1 and the time of the first period that is a non-operation time when performing instantaneous tripping. It shall include the set value of the width. The operating characteristic curve of the circuit breaker 1 shows that when the overcurrent exceeding the rated current of the circuit breaker 1 (or the rated current of the circuit breaker 11; the same applies hereinafter) flows through the circuit breaker 1 It is the curve which showed the relationship with the operation time until it interrupts | blocks the part 11. FIG. An example is shown in FIG. In the operating characteristic curve shown in FIG. 2, the horizontal axis represents current and the vertical axis represents time, and both are logarithmic scales. The operating characteristic curve shown in FIG. 2 shows the relationship between the time delay until the circuit breaker 11 is cut off and the magnitude of the overcurrent when an overcurrent flows through the circuit breaker 1. The operating characteristic curve is defined as, for example, Japanese Industrial Standard. In the example shown in FIG. 2, the circuit breaker 11 does not operate for the rated current In. That is, when a current equal to or lower than the rated current In is detected, the first cutoff control unit 182 and the second cutoff control unit 183 do not block the current flowing through the circuit by the circuit cutoff unit 11. It operates within a time T3 at a current 1.25 times the rated current In. That is, when a current 1.25 times the rated current In is detected, the second cutoff control unit 183 cuts off the current flowing through the circuit by the circuit cutoff unit 11 within the time T3. Further, it operates within a time T2 at a current twice the rated current In. That is, when a current twice the rated current In is detected, the second cutoff control unit 183 cuts off the current flowing through the circuit within the time T2 by the circuit cutoff unit 11. The shut-off operation by the second shut-off control unit 183 is called a time extension removal operation.

  The first threshold value is a current threshold value for immediately shutting down the circuit when a current exceeding the first threshold value is detected due to a relatively large overcurrent such as a short circuit current. That is, the first threshold value is a current threshold value when instantaneous tripping is performed. The first threshold value can be set, for example, in the form of a first constant multiple of the rated current. Here, the rated current may be the rated current of the circuit breaker 1 described above (that is, the rated current of the circuit breaker 11) In or the rated current of the lightning transformer 3. For example, when the primary side of a transformer such as the lightning resistant transformer 3 is connected to the output side of the circuit breaker 1, the value of the first threshold value is set to a value obtained by multiplying the rated current of the transformer by a first constant multiple. Is set, the relationship between the inrush current of the transformer and the first threshold value can be grasped more directly. In the following, the case where the value of the first threshold value is set in the form of a first constant multiple of the rated current In of the circuit interrupting unit 11 will be described as an example, but the rated current In can be read as the rated current of the transformer. Note that the value of the rated current of the transformer can be stored in a nonvolatile memory or the like so that it cannot be changed, for example, at the factory shipment stage, or can be changed using, for example, the operation unit 19. In the example shown in FIG. 2, when a current exceeding the first constant multiple (= first threshold value) of the rated current In is detected, the circuit breaker 11 operates within the time T1. That is, when a current that is a first constant multiple of the rated current In is detected, the first cutoff control unit 182 cuts off the current flowing through the circuit by the circuit cutoff unit 11 within the time T1. The shut-off operation performed by the first shut-off control unit 182 is called an instantaneous trip operation.

  On the other hand, the non-operation time (that is, the first period) when performing instantaneous tripping, which is another set value included in the shut-off characteristics, is a period of time during which instantaneous tripping is deactivated continuously after the power is turned on. Means the set value. In the characteristic diagram of FIG. 2, the setting value is related to the characteristic of the portion A indicated by hatching, but is not a setting value that affects the characteristic of the time-delay operation performed by the second cutoff control unit 183. In addition, the set value of the non-operation time (that is, the first period) is not limited to one, and for example, a plurality of set values can be determined according to the current.

  For example, the initialization processing unit 181 sets the value of the first constant to be changeable or sets the time width of the first period according to the characteristics of the transformer, so that the breaking characteristics of the circuit breaker 1 are changed. The breaking characteristics of the circuit breaker 1 are initialized so that the breaking characteristics according to the characteristics of a predetermined transformer are obtained. However, the value of the first constant may be set to a predetermined value at the factory shipment stage so that it cannot be changed. For example, the initialization processing unit 181 changes the value of the first constant according to the operation state of the operation element of the operation unit 19 or uses the value of the first constant stored in advance in the nonvolatile memory. Thus, the set value of the first threshold value (= rated current In × first constant) shown in FIG. 2 is calculated. For example, as illustrated in FIG. 2, the initialization processing unit 181 can change the first threshold value (initial value) to a larger first threshold value (after the initialization process). Alternatively, the initialization processing unit 181 sets a predetermined value determined in advance from the factory shipment stage as the first threshold value. Here, the value of the first constant can be a value of several times to about several times, for example, but is not limited to this value. At that time, the initialization processing unit 181 sets the value of the first constant so that the rated current In multiplied by the first constant is equal to or less than the maximum allowable current of the line interrupting unit 11 shown by the curve B in FIG. . The maximum allowable current is the maximum current that can be safely interrupted by the line interrupting unit 11.

  Further, the initialization processing unit 181 sets the time width of the first period by changing the initial processing time of the control unit 10 according to the characteristics of the transformer. The initial processing time of the control unit 10 is a time required for initial processing for initialization or the like when the microcomputer 18 is started up (that is, when power is turned on). As an initial process, the microcomputer 18 starts execution of a program stored at a preset address at the time of activation, initializes input / output terminals, initializes an A / D converter, and initializes timers and counters. Processes such as initial setting of various interrupts and memory inspection. After the initial processing, the microcomputer 18 starts current value acquisition processing. Therefore, when the microcomputer 18 is activated when the circuit 14 is turned on by closing the contact 14 or returning power, at least the time until the initial processing time elapses after the power is turned on to the circuit is obtained. Is not done. Accordingly, at least until the initial processing time elapses, the circuit interrupting unit 11 does not interrupt the circuit under the control of the microcomputer 18. Therefore, the initialization processing unit 181 can set the time width of the first period by changing the initial processing time of the control unit 10.

  Further, the initialization processing unit 181 can initialize the breaking characteristics of the circuit breaker 1 based on the result of detecting the inrush current flowing when the transformer is connected to the output side of the circuit breaking unit 11 by the current transformer 13. .

  In addition, the 2nd interruption | blocking control part 183 is when the current transformer 13 detects the electric current smaller than a 1st threshold value (= 1st constant multiple of rated current In) and larger than the rated current of the circuit interruption | blocking part 11 as mentioned above. The circuit blocking unit 11 performs a process of blocking the circuit based on a predetermined operating characteristic curve. At that time, it is desirable that the second cutoff control unit 183 is configured so that the circuit is not cut off by the rated current In. For example, when the current transformer 13 detects a current exceeding the rated current multiplied by a second constant times smaller than the first constant multiple, the second cutoff control unit 183 is based on a predetermined operating characteristic curve by the circuit breaker 11. It can be set as the structure which interrupts | blocks the electric current which flows into a circuit. The value of the first constant is 200% or more in the normal specification regardless of whether the rated current used when calculating the first threshold is the rated current of the circuit breaker 11 or the rated current of the transformer. On the other hand, the value of the second constant can be set to a value of about 110%, for example, smaller than the first constant.

  In addition, although the circuit breaker 1 shown in FIG. 1 is set as the structure of the number of terminals and the number of contacts of 3, ie, 3 pole 3 element, the number of poles and the number of elements are not limited to this. The number of poles and the number of elements can be arbitrarily set to one or more in accordance with the configuration of the lead-in wire connected to the power supply side terminal 21 or the load side terminal 22 or electrical equipment. Moreover, although the some current transformer 13 is provided in the some bus bar 24, respectively, it is omissible suitably. Moreover, you may detect the electric current which flows into the bus-bar 24 using other detectors, such as a current detector using a Hall element, for example instead of the current transformer 13. Further, the control circuit 12 can operate using, for example, a current output from a plurality of current transformers 13 or an additional current transformer (not shown) as a power source.

  The circuit breaker 1 shown in FIG. 1 may include a circuit breaker 11, a control circuit 12, a plurality of current transformers 13, and an operation unit 19, for example, in one housing. Can be configured separately. In that case, the circuit breaker 11 can be configured as a circuit breaker, and the control circuit 12 can be configured as a protective relay (that is, a protection relay). The plurality of current transformers 13 can also be provided in a circuit breaker constituting the circuit breaker 11. Further, the plurality of bus bars 23 and 24 can be appropriately replaced with cables or the like.

  In this application, the circuit breaker is a power supply side terminal, a load side terminal, a contact provided in a circuit between the power supply side terminal and the load side terminal, and when a predetermined overcurrent flows through the circuit. It means an opening / closing means having a configuration for opening the contact. In this case, the circuit breaker can also be referred to as a circuit breaker, MCCB (Molded Case Circuit Breaker), MCB (Molded Circuit Breaker), breaker, or the like.

  Next, an operation example of the circuit breaker 1 shown in FIG. 1 will be described with reference to FIGS. FIG. 3 is a flowchart showing a flow of processing executed by the microcomputer 18 shown in FIG. 4 and 5 show a waveform schematically showing the absolute value of the current value I1 flowing through the single bus bar 24 shown in FIG. 1, and the time when the microcomputer 18 starts to acquire the current value I1. It is a timing chart. In FIG. 4, the initial processing time is left as the initial value, and in FIG. 5, the initial processing time is changed from the initial value.

  Note that the flowchart shown in FIG. 3 shows the flow of processing related to tripping control based on the current value I1 for one phase for the sake of simplicity. Actually, the microcomputer 18 performs tripping control of each contact 14 when an overcurrent or a short-circuit current is detected in any one of the currents detected by the current transformers 13. That is, the microcomputer 18 executes the same processing as that shown in FIG. 3 sequentially or in parallel for the number of current transformers 13.

  When each contact 14 is closed with the power supply connected to each power supply side terminal 21 or when power is restored with each contact 14 closed during a power failure, the microcomputer 18 is shown in FIG. Start processing. First, the microcomputer 18 starts an initial process (step S101). Next, the microcomputer 18 determines whether or not there is an initialization instruction (step S102). The initialization instruction is an instruction for an operator to request execution of a process for initializing the breaking characteristics of the circuit breaker 1. For example, when the operator turns on the power while operating a predetermined operation element provided on the operation unit 19, or when the state of the operation element for setting an instruction value according to the characteristics of the transformer is changed. The microcomputer 18 determines that an initialization instruction has been given. If the microcomputer 18 determines that an initialization instruction has been given (YES in step S102), the microcomputer 18 resets the initialization flag (step S103). The initialization flag is a flag stored in a predetermined storage area that has been reset at the time of shipment from the factory, and indicates that the initialization process has not been executed yet or that re-execution has been instructed.

  Next, the microcomputer 18 acquires the current value I1 based on the output of the current transformer 13 (step S104). Note that the process of step S104 is executed at a predetermined sampling period (for example, every 1 millisecond). Further, the value acquired in the process of step S104 is not the current value itself flowing through the bus bar 24 but a value corresponding to the current value I1, but for the sake of simplicity, a value corresponding to the current value I1 will be described below. Is simply described as a current value I1. In step S104, the absolute value of the current value I1 may be acquired.

  Next, in the microcomputer 18, the first cutoff control unit 182 compares the absolute value of the current value I1 acquired in step S104 with the first threshold value, and whether the absolute value of the current value I1 exceeds the first threshold value. It is determined whether or not (step S105).

  Here, the operation example shown in FIGS. 4 and 5 will be described. FIG. 4 schematically shows operation waveforms when a transformer inrush current is generated with the circuit in a normal state when the power is turned on. FIG. 5 schematically shows operation waveforms when an abnormal state such as a short circuit normal state occurs in the circuit when the power is turned on. In the example shown in FIG. 4, the absolute value | I1 | of the current value I1 attenuates while changing the peak value of the overcurrent generated every half cycle according to the inrush current decay curve. The inrush current decay curve and the peak value vary depending on the characteristics and individual differences of the transformer, the residual magnetic flux, the voltage phase when the power is turned on, and the load of the transformer. On the other hand, the microcomputer 18 starts obtaining the current value I1 after time t12 when the initial processing time (initial value) has elapsed since the power was turned on at time t11 (step S104). In the example shown in FIG. 4, the absolute value | I1 | of the current value I1 is attenuated to a value equal to or less than the first threshold value at time t12. Therefore, since the first cutoff control unit 182 determines that the absolute value of the current value I1 does not exceed the first threshold (NO in step S105), the first cutoff control unit 182 does not perform control for cutting off the circuit (step S106).

  On the other hand, in the example shown in FIG. 5, the absolute value | I1 | of the current value I1 is an overcurrent having a peak value of the same magnitude for each half cycle. The microcomputer 18 starts to acquire the current value I1 after time t22 when the initial processing time (after initialization processing) has elapsed since the power was turned on at time t21 (step S104). In the example shown in FIG. 5, even after time t22, the absolute value | I1 | of the current value I1 is a value exceeding the first threshold value. Therefore, since the first cutoff control unit 182 determines that the absolute value of the current value I1 exceeds the first threshold (YES in step S105), the first cutoff control unit 182 performs control to shut off the circuit (step S106). That is, in step S <b> 106, the microcomputer 18 performs control to excite the tripping coil 15 and shuts off the circuit shut-off unit 11.

  When the first cutoff control unit 182 determines in step S105 that the absolute value of the current value I1 does not exceed the first threshold value (in the case of NO in step S105), the second cutoff control unit 183 determines based on the operating characteristic curve. Processing is performed (S107). That is, the second cutoff control unit 183 determines, for example, whether the effective value of the current value I1 and the past time change of the effective value satisfy the cutoff condition based on the operating characteristic curve as shown in FIG. When it is determined that the interruption condition based on the operating characteristic curve is satisfied (YES in step S108), the second interruption control unit 183 performs control to interrupt the circuit (step S106).

  When the second cutoff control unit 183 determines in step S108 that the cutoff condition based on the operating characteristic curve is not satisfied (NO in step S108), the initialization processing unit 181 needs to execute the initialization process. It is determined whether or not (step S109). When the initialization flag is in the reset state, that is, when the initialization process has not been performed once after factory shipment or the initialization process is instructed again by the operator, the initialization processing unit 181 executes the initialization process. It is determined that it is necessary to do so (YES in step S109). If the initialization processing unit 181 determines that the initialization process needs to be executed (YES in step S109), the initialization processing unit 181 executes the initialization process (step S110).

  In step S110, the initialization processing unit 181 changes the setting value of the first constant according to, for example, the operation state of the operation unit 19 to thereby change the first threshold value (= first constant × rated current In) shown in FIG. ). For example, as illustrated in FIG. 2, the initialization processing unit 181 changes the value of the first threshold value from the first threshold value (initial value) to the first threshold value (after initialization processing), and sets the operation characteristic curve. Change as shown by the dashed line. In step S110, the initialization processing unit 181 sets an initialization flag after the initialization process is completed.

  Further, in step S110, the initialization processing unit 181 performs, for example, a first period (that is, initial processing time) according to the operation state of the operation unit 19 or based on one or a plurality of sampling values of the current value I1 acquired in step S104. ) Change the time span. For example, the time width of the initial processing time can be changed by changing the number of repetitions of the repetition processing in the program executed in the initial processing in step S101 or changing the waiting time realized using a timer or the like. The time span can be changed. For example, as illustrated in FIG. 4, the initialization processing unit 181 can change the initial processing time according to the result of comparing the current value I1 acquired after power-on with the value of the first threshold value. As shown in FIG. 2, the initialization processing unit 181 can change the initial processing time from, for example, an initial processing time (initial value) to a shorter initial processing time (after initialization processing). it can. When the initial processing time is shortened, as shown in FIG. 5, the acquisition start time of the current value I1 can be set to time t22 earlier than time t23. The initialization processing unit 181 sets the initial processing time setting value according to, for example, the combination of the operation state of the operation unit 19 and the current value I1 acquired in step S104, or sets only the operation state of the operation unit 19 Accordingly, a setting value for the initial processing time can be set. In addition, when the initialization processing unit 181 performs the initialization processing based on a plurality of sampling values, the initialization processing unit 181 executes the initialization processing after acquiring a plurality of sample values.

  In step S110, the initialization processing unit 181 may change both the first threshold and the first period, or may change only one of them.

  If it is determined in step S109 that the initialization process is not necessary (NO in step S109) or if the process in step S110 is completed, the microcomputer 18 obtains the current value I1 at the next sampling time in step S102. Get it again.

  As described above, the circuit breaker 1 according to the present embodiment initializes the circuit breaker 1 with the initialization processing unit 181 so that the circuit breaker 1 has a circuit breaker characteristic corresponding to a predetermined transformer characteristic. And when the current transformer 13 (current detection unit) detects a current greater than a predetermined first threshold after a predetermined first period has elapsed since the circuit was turned on by the first cutoff control unit 182 The current flowing in the circuit is cut off by the unit 11. In this configuration, even if the value of the first threshold value that is the threshold value of the trip operation is not changed, the value of the first period is changed so that the value of the inrush current of the transformer does not exceed the first threshold value. it can. Therefore, for example, even when the first threshold is set according to the rated current, an unnecessary trip due to the inrush current can be easily prevented without increasing the rated current.

  Further, the circuit breaker 1 of the present embodiment is configured so that the circuit breaker 11 causes a circuit when the current transformer 13 (current detection unit) detects a current exceeding the rated current of the lightning transformer 3 multiplied by a predetermined first constant. And a predetermined operation when the current transformer 13 detects a current exceeding the rated current of the circuit breaker 11 and a second constant times smaller than the first constant multiple. And a second cutoff control unit 183 that cuts off a current flowing through the circuit by the circuit cutoff unit 11 based on the characteristic curve. In this configuration, if the value obtained by multiplying the rated current of the lightning resistant transformer 3 by the first constant is larger than the inrush current of the lightning resistant transformer 3, the operation based on the predetermined operating characteristic curve by the second interruption control unit 183 is achieved. An unnecessary trip due to the inrush current of the transformer by the first cutoff control unit 182 can be prevented without influencing. Therefore, an unnecessary trip due to an inrush current can be easily prevented without increasing the rated current that determines the operating characteristic curve.

  In the configuration shown in FIG. 1, for example, the rated capacity of the lightning proof transformer 3 can be set based on the rated power of the electric device 4 or the like. On the other hand, the rated current of the circuit breaker 1 has conventionally been set according to the rated capacity of the lightning resistant transformer 3 and the magnitude of the inrush current, whereas in this embodiment, the circuit breaker 11 due to the inrush current is used. Since unnecessary trips can be prevented, the amount of equipment used can be commensurate. Therefore, even if the equipment cost is reduced so that the reset breaker can be omitted, and the rated current of the circuit breaker 1 (that is, the circuit breaker 11) is used as a contract current (also referred to as a contract ampere) to receive power supply from an electric power company. There is a merit of electricity bill reduction by reducing amperage.

  FIG. 6 shows an example of the measurement result of the inrush current waveform in the configuration shown in FIG. However, the waveform shown in FIG. 6 is a measurement result in a state where the electrical device 4 is not connected. Each measured value was measured by attaching a measuring instrument to the outside of the circuit breaker 1. The measurement result shown in FIG. 6 shows that each current value I1, I2 and IN of each phase shown in FIG. 6 and the voltage V1 between the voltage line L1 and the neutral line N are sampled at a predetermined cycle. The time change of the value is shown. The unit of the vertical axis is 200 A / DIV for the current value and 200 V / DIV for the voltage value. The unit of the horizontal axis is 25 ms / DIV. Moreover, the frequency of AC power is 50 Hz.

  On the other hand, the power supply system 300 is a system for supplying power to a power user (that is, a consumer) from the power dispatch distribution system 100 and charging the user with an electricity fee. As described above, the power supply system 300 includes at least the circuit breaker 1 and the electricity rate calculation unit 200. In the power supply system 300, the circuit breaker 1 is used as a contract breaker. That is, the contract current (or contract power) is set by the rated current of the circuit breaker 1. The electricity bill calculation unit 200 is, for example, a computer such as a server, and uses, for example, a database that manages the contents of use contracts, electricity usage for a plurality of months, and electricity bills for a plurality of power users. The electricity charge for each user is calculated according to the unit price determined in advance. The used electric energy is directly or indirectly input from the watt-hour meter 2 to the electricity rate calculation unit 200. For example, the measured value of the watt-hour meter 2 is collected by a predetermined company that operates the power dispatch distribution system 100, and information indicating the collection result is provided from the company to the electricity rate calculation unit 200, The business operator who operates the power supply system 300 can collect the measured value of the watt-hour meter 2 and input it to the electricity rate calculation unit 200 online or offline. Since the power supply system 300 of the present embodiment can appropriately set the rated current of the circuit breaker 1 as described above even when a transformer is connected to the output side of the circuit breaker 1, it is possible for the user to Can charge an appropriate electricity bill.

  As mentioned above, although one Embodiment of the circuit breaker 1 of this invention was described, embodiment of this invention is not limited to said thing. In the embodiment of the present invention, for example, the above embodiment can be modified as follows. That is, in the microcomputer 18, for example, the first cutoff control unit 182 and the second cutoff control unit 183 can be integrally configured. Further, the contact 14 is not limited to a mechanical type, and may be configured using a semiconductor element. In that case, the tripping coil 15 and the like can be omitted. Further, the elapsed time after power-on described with reference to FIG. 4 and the like is not limited to the initial processing time as described above, and for example, it is determined whether or not the first period has elapsed since power-on. This can be ensured by using the processing to be performed and the processing to deactivate the blocking operation until the first period elapses.

  The program executed by the microcomputer 18 can be distributed using a computer-readable recording medium or a communication line.

DESCRIPTION OF SYMBOLS 1 Circuit breaker 2 Electricity meter 3 Lightning-proof transformer 10 Control part 11 Circuit interruption part 12 Control circuit 13 Current transformer 14 Contact 15 Tripping coil 16 Output part 17 Input part 18 Microcomputer 21 Power supply side terminal 22 Load side terminals 23 and 24 Bus bar 181 Initialization processing unit 182 First blocking processing unit 183 Second blocking processing unit 100 Electric power dispatch distribution system 200 Electricity charge calculation unit 300 Electric power supply system

Claims (6)

A circuit breaker comprising a circuit breaker that cuts off a current flowing in a circuit that supplies power to the transformer, and a controller that breaks the circuit breaker by electronic control,
The controller is
A current detector for detecting a current flowing in the circuit;
A first cutoff control unit that cuts off a current flowing through the circuit by the circuit cutoff unit when the current detection unit detects a current that exceeds the rated current of the transformer multiplied by a predetermined first constant;
When the current detecting unit detects a current exceeding the rated current of the circuit interrupting unit multiplied by a second constant times smaller than the first constant multiple, the circuit interrupting unit flows into the circuit based on a predetermined operating characteristic curve. A second cutoff control unit for cutting off the current;
An initialization processing unit for determining a cutoff characteristic of the circuit cutoff unit corresponding to the operation state based on an operation state of the operation unit;
With
The circuit breaker characterized in that the information for determining the breaking characteristic of the circuit breaker includes information indicating a predetermined period during which the first break controller is inoperative. The initialization processing unit
Determining the predetermined period corresponding to the transformer;
The first shutoff controller is
Until the predetermined period elapses after energization of the circuit including the circuit interruption unit is performed, the current flowing through the circuit is not interrupted by the circuit interruption unit. 2. The circuit breaker according to claim 1, wherein when the current detection unit detects a current exceeding a current multiplied by a predetermined first constant, the circuit breaker blocks the current flowing through the circuit. The initialization processing unit
3. The interruption according to claim 1, wherein the first constant is set according to an operation state of the operation unit until the predetermined period elapses after energization of the circuit including the circuit interruption unit is started. vessel. The initialization processing unit
Based on the operation state of the operation unit, it is determined whether or not the interruption characteristic of the circuit interruption unit needs to be changed, and the interruption characteristic of the circuit interruption unit corresponding to the operation state is determined according to the determination result. The circuit breaker according to any one of claims 1 to 3, wherein a constant is defined. Wherein the initialization processing unit is characterized by what the rated current of the transformer and the first constant times to set the value of the first constant so as not to exceed the maximum allowable current of the circuits blocking part The circuit breaker according to any one of claims 1 to 4. The circuit breaker according to any one of claims 1 to 5,
An electric charge calculating unit that calculates an electric charge according to the value of the rated current of the circuit interrupting unit.

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