JP7487847B2 - Diagnostic device, circuit breaker, and diagnostic method - Google Patents

Description

The present disclosure relates to a diagnostic device, a circuit breaker, and a diagnostic method.

2. Description of the Related Art There is known a circuit breaker that includes an auxiliary switch that is linked to an ON operation of the circuit breaker and an alarm switch that is linked to a trip operation of the circuit breaker (see, for example, Patent Document 1).

JP 2007-234496 A

With conventional circuit breakers, when an interruption (tripping) operation occurs, it is only possible to determine by visual inspection or other means using the five senses whether the interruption (tripping) operation has occurred due to an overcurrent or a short circuit.

An object of the present disclosure is to provide a diagnostic device that, when a circuit breaker performs an interrupting operation, diagnoses a cause of the interrupting operation of the circuit breaker.

According to one aspect of the present disclosure, a diagnostic device is provided that includes a current detection unit that measures a current value of a current flowing through a circuit breaker, a voltage detection unit that measures a voltage value of a secondary side voltage of the circuit breaker, and a diagnostic unit that diagnoses a cause of an interruption when the circuit breaker is interrupted from the current value measured by the current detection unit, wherein the diagnostic unit diagnoses the cause of the interruption when the voltage value measured by the voltage detection unit drops, based on the current value immediately before the voltage value measured by the voltage detection unit.

According to the diagnosis device of the present disclosure, when a circuit breaker performs an interruption operation, it is possible to diagnose the cause of the interruption operation of the circuit breaker.

FIG. 1 is a diagram for explaining connections of a diagnostic device according to the first embodiment. FIG. 2 is a diagram for explaining the operation of the circuit breaker diagnosed by the diagnosis device according to the first embodiment. FIG. 3 is a functional block diagram illustrating the functional configuration of the diagnostic device according to the first embodiment. FIG. 4 is a flow diagram illustrating the processing of the diagnostic device according to the first embodiment. FIG. 5 is a flow diagram illustrating the processing of the diagnostic device according to the first embodiment. FIG. 6 is a flow diagram illustrating the processing of the diagnostic device according to the first embodiment. FIG. 7 is a diagram for explaining the temporal operation of the processing of the diagnostic device according to the first embodiment. FIG. 8 is a diagram for explaining connections of a diagnostic device according to the second embodiment. FIG. 9 is a diagram for explaining connections of a diagnostic device according to the third embodiment. FIG. 10 is a functional block diagram illustrating the functional configuration of a diagnostic device according to the third embodiment. FIG. 11 is a diagram for explaining connections of a diagnostic device according to the fourth embodiment. FIG. 12 is a functional block diagram illustrating the functional configuration of a diagnostic device according to the fourth embodiment. FIG. 13 is a diagram for explaining connections of a diagnostic device according to the fifth embodiment. FIG. 14 is a functional block diagram illustrating the functional configuration of a diagnostic device according to the sixth embodiment. FIG. 15 is a diagram for explaining the temporal operation of the processing of the diagnostic device according to the seventh embodiment. FIG. 16 is a diagram for explaining the diagnosis of a circuit breaker performed by the diagnosis device according to the eighth embodiment.

Hereinafter, each embodiment of the present invention will be described with reference to the accompanying drawings. Note that, in the description of the specification and drawings relating to each embodiment, components having substantially the same or corresponding functional configurations may be given the same reference numerals to avoid redundant description. In addition, in order to facilitate understanding, the scale of each part in the drawings may differ from the actual scale.

First Embodiment
First, a description will be given of a diagnostic device 10 according to the first embodiment. Fig. 1 is a diagram for explaining connections of the diagnostic device 10 according to the first embodiment.

The diagnostic device 10 diagnoses the circuit breaker 1. Specifically, when the circuit breaker 1 opens the electric path to interrupt the supply of power from the primary side to the secondary side, the diagnostic device 10 diagnoses the cause (interruption cause) of the circuit breaker 1 interrupting the supply of power.

Here, a circuit breaker 1 that connects or breaks an electric path for power supplied from a power source 2, which is a three-phase AC power source, to a load 3 will be described as an example of an object to be diagnosed by the diagnostic device 10 according to the first embodiment. The load 3 is, for example, a three-phase motor.

The circuit breaker 1 is connected to the power source 2 via a connection wiring W1 including a wiring W1r, a wiring W1s, and a wiring W1t. That is, the power source 2 is connected to the primary side of the circuit breaker 1.

The circuit breaker 1 is also connected to the load 3 via the diagnostic device 10. Specifically, the circuit breaker 1 is connected to the diagnostic device 10 via a connection wiring W2 including a wiring W2r, a wiring W2s, and a wiring W2t. The diagnostic device 10 is then connected to the load 3 via a connection wiring W3 including a wiring W3r, a wiring W3s, and a wiring W3t.

The diagnostic device 10 is connected to a higher-level control device 5 via a network such as a LAN (Local Area Network).

Next, the circuit breaker 1 that is the subject of diagnosis by the diagnosis device 10 will be described.

[Circuit breaker 1]
The circuit breaker 1 opens an electric path through which the current flows from the primary side to the secondary side when a current larger than a predetermined rated current flows from the primary side to the secondary side, thereby cutting off the supply of power from the primary side to the secondary side. The circuit breaker 1 is a so-called breaker. In the present disclosure, the circuit breaker 1 connects or cuts off an electric path of power supplied from a power source 2, such as a three-phase AC power source, to a load 3.

The circuit breaker 1 includes an operating lever 1a. When the operating lever 1a is tilted to one side, for example, the upper side in Fig. 1, the circuit breaker 1 connects an electric path through which a current flows from the primary side to the secondary side. On the other hand, when the operating lever 1a is tilted to the other side, for example, the lower side in Fig. 1, the circuit breaker 1 interrupts the electric path through which a current flows from the primary side to the secondary side.

Fig. 2 is a diagram for explaining the operation of the circuit breaker 1 diagnosed by the diagnosis device 10 according to the first embodiment. The horizontal axis of Fig. 2 represents the current flowing through the circuit breaker 1. The vertical axis of Fig. 2 represents the time (operation time) until the circuit breaker 1 cuts off the supply of power when an overcurrent larger than the rated current flows.

The current value Ith1 is the rated current value of the circuit breaker 1. When the current value of the current flowing through the circuit breaker 1 is equal to or less than the current value Ith1 (normal operating condition Cn), the circuit breaker 1 does not cut off the power supply. In other words, when the current value of the current flowing through the circuit breaker 1 is equal to or less than the current value Ith1 (normal operating condition Cn), the circuit breaker 1 continues to supply power.

On the other hand, when the current value of the current flowing through the circuit breaker 1 is greater than the current value Ith1 (breaking operation condition Ct), the circuit breaker 1 cuts off the supply of power after the operation time for the current value determined by the characteristic curve Lsp shown in Fig. 2 has elapsed. The current value Ith1 may be referred to as the breaking operation current value. The operation time for the current value determined by the characteristic curve Lsp shown in Fig. 2 differs across a current value Ith2 that is greater than the current value Ith1. The current value Ith2 is, for example, about 10 times the current value Ith1, which is the rated current value of the circuit breaker 1.

Specifically, when the current value of the current flowing through the circuit breaker 1 is greater than the current value Ith1 and less than the current value Ith2 (inverse time operation condition Ct1), the circuit breaker 1 operates inversely to interrupt the electrical path of the circuit breaker 1. In the case of inverse time operation, the circuit breaker 1 cuts off the supply of power after a short delay before operation if a large current flows through the circuit breaker 1, and after a long delay before operation if a small current flows through the circuit breaker 1.

Furthermore, when the current value of the current flowing through the circuit breaker 1 is equal to or greater than the current value Ith2 (instantaneous operation condition Ct2), the circuit breaker 1 instantaneously cuts off the supply of power. Note that the current value Ith2 may be referred to as the instantaneous operation current value.

[Diagnostic device 10]
The diagnostic device 10 diagnoses the cause of interruption when the circuit breaker 1 opens the electrical path, based on the secondary voltage and the current flowing through the circuit breaker 1 .

The diagnostic device 10 is a standalone device that is installed near the circuit breaker 1 .

Specifically, if the current value of the current flowing through the circuit breaker 1 when the circuit breaker 1 opens the electric path is equal to or less than the current value Ith1 that is the rated current value of the circuit breaker 1, the diagnostic device 10 determines that the operating lever 1a has been operated to operate the circuit breaker 1. In other words, the diagnostic device 10 determines that the interruption was caused by manual operation.

Furthermore, if the current value of the current flowing through the circuit breaker 1 when the circuit breaker 1 opens the electrical path is greater than the current value Ith1, which is the rated current value of the circuit breaker 1, and less than the current value Ith2, the diagnostic device determines that an overcurrent has flowed and caused the breaking operation. In other words, the diagnostic device 10 determines that the breaking was caused by an overcurrent.

Furthermore, if the current value of the current flowing through the circuit breaker 1 when the circuit breaker 1 opens the electrical path is equal to or greater than the current value Ith2, the diagnostic device 10 determines that the breaking operation is caused by a short circuit. That is, the diagnostic device 10 determines that the breaking operation is caused by a short circuit.

A specific description will be given of the diagnostic device 10. Fig. 3 is a functional block diagram illustrating the functional configuration of the diagnostic device 10 according to the first embodiment.

The diagnostic device 10 includes a control unit 11, a power calculation unit 12, a voltage detection unit 13r, a voltage detection unit 13s, and a voltage detection unit 13t, a current detection unit 14r, a current detection unit 14s, and a current detection unit 14t, and a communication unit 15. The diagnostic device 10 also includes internal wiring that connects the wiring included in the connection wiring W2 and the wiring included in the connection wiring W3. Specifically, the diagnostic device 10 includes internal wiring Lr that connects the wiring W2r of the connection wiring W2 and the wiring W3r of the connection wiring W3, internal wiring Ls that connects the wiring W2s and the wiring W3s, and internal wiring Lt that connects the wiring W2t and the wiring W3t.

(Control unit 11)
The control unit 11 controls the entire diagnostic device 10. The control unit 11 also diagnoses the cause of interruption of the circuit breaker 1 based on the current value and voltage value calculated by the power calculation unit 12.

The control unit 11 is configured by, for example, a microprocessing unit including a central processing unit (CPU), a random access memory (RAM), and a read only memory (ROM). The control unit 11 performs processing by the CPU expanding a program recorded in the ROM into the RAM and executing the program.

(Power Calculation Unit 12)
The power calculation unit 12 calculates power based on the voltage values detected by the voltage detection units 13r, 13s, and 13t, respectively, and the current values detected by the current detection units 14r, 14s, and 14t, respectively. The power calculation unit 12 is configured by, for example, a dedicated IC (Integrated Circuit) or the like.

(Voltage detection unit 13r, voltage detection unit 13s, and voltage detection unit 13t)
The voltage detection unit 13r, the voltage detection unit 13s, and the voltage detection unit 13t detect the voltage (potential difference) between the internal wiring Lr and the internal wiring Ls, between the internal wiring Ls and the internal wiring Lt, and between the internal wiring Lt and the internal wiring Lr, respectively. Each of the voltage detection unit 13r, the voltage detection unit 13s, and the voltage detection unit 13t is composed of, for example, a voltage transformer. The voltage detection unit 13r is connected to the internal wiring Lr and the internal wiring Ls. The voltage detection unit 13s is connected to the internal wiring Ls and the internal wiring Lt. The voltage detection unit 13t is connected to the internal wiring Lt and the internal wiring Lr.

The voltages (potential differences) detected by the voltage detection units 13r, 13s, and 13t are converted into specific voltage values by the power calculation unit 12.

(Current detection unit 14r, current detection unit 14s, and current detection unit 14t)
The current detection units 14r, 14s, and 14t detect the currents flowing through the internal wiring Lr, Ls, and Lt, respectively. Each of the current detection units 14r, 14s, and 14t is configured, for example, by a current transformer. The current detection units 14r, 14s, and 14t are attached to the internal wiring Lr, Ls, and Lt, respectively.

The currents detected by the current detection units 14r, 14s, and 14t are converted into specific current values by the power calculation unit 12.

(Communication unit 15)
The communication unit 15 controls communication with the control device 5. The communication unit 15 is formed of, for example, a communication IC.

<Processing of diagnostic device 10>
Next, the process (diagnosis method) in the diagnosis device 10 will be described. Figures 4, 5, and 6 are flow diagrams explaining the process of the diagnosis device 10 according to the first embodiment. Specifically, Figures 4, 5, and 6 are flow diagrams explaining the procedure executed by the control unit 11 of the diagnosis device 10 and the procedure of the program executed by the control unit 11.

The control unit 11 of the diagnostic device 10 executes a process of calculating an effective value (effective value calculation process) shown in Fig. 4 and a process of determining a cause of interruption of the circuit breaker 1 (interruption cause determination process) shown in Fig. 5 and Fig. 6. The control unit 11 of the diagnostic device 10 executes each of the process of calculating an effective value (effective value calculation process) shown in Fig. 4 and the process of determining a cause of interruption of the circuit breaker 1 (interruption cause determination process) shown in Fig. 5 and Fig. 6 at a predetermined cycle (for example, a cycle of several milliseconds (ms)).

First, the process of calculating the effective value (effective value calculation process) shown in FIG. 4 will be described.

(Step S10)
When the process starts, the control unit 11 controls the power calculation unit 12 to measure the current and voltage. Then, the control unit 11 obtains the current value and voltage value measured by the power calculation unit 12.

The current values are the R-phase current value detected by current detection unit 14r, the S-phase current value detected by current detection unit 14s, and the T-phase current value detected by current detection unit 14t, while the voltage values are the UV line voltage value detected by voltage detection unit 13r, the VW line voltage value detected by voltage detection unit 13s, and the WU line voltage value detected by voltage detection unit 13t.

(Step S20)
Next, the control unit 11 calculates the effective values of the current and voltage from the current and voltage values measured by the power calculation unit 12 .

Next, a process for determining a cause of interruption of the circuit breaker 1 shown in Figs. 5 and 6 (a process for determining a cause of interruption) will be described.

(Step S30)
Next, the control unit 11 judges whether the effective value of the current flowing through the circuit breaker 1 is equal to or greater than the instantaneous operating current value, i.e., the current value Ith2. The effective value of the current to be judged is the effective value of at least one of the R-phase current value, the S-phase current value, and the T-phase current value. The effective value of the current to be judged may be the effective value calculated by the effective value calculation process, or may be the effective value of at least one of the R-phase current value, the S-phase current value, and the T-phase current value newly calculated using the current detection unit 14r, the current detection unit 14s, and the current detection unit 14t. When it is judged that the effective value of the current flowing through the circuit breaker 1 is equal to or greater than the instantaneous operating current value (Yes in step S30), the control unit 11 advances the process to step S40. When it is judged that the effective value of the current flowing through the circuit breaker 1 is smaller than the instantaneous operating current value (No in step S30), the control unit 11 advances the process to step S110.

(Step S40)
Next, the control unit 11 starts measuring time using a timer.

(Step S50)
Next, the control unit 11 determines whether the electric path has been interrupted by the circuit breaker 1. Specifically, the control unit 11 determines whether the electric path has been interrupted by the circuit breaker 1 based on whether the voltage has dropped below a predetermined voltage.

First, the control unit 11 controls the power calculation unit 12 to measure the current and voltage. Then, the control unit 11 acquires the voltage value measured by the power calculation unit 12. Next, the control unit 11 judges whether the acquired voltage value, that is, the voltage on the secondary side of the circuit breaker 1, has dropped. If it is judged that the voltage on the secondary side of the circuit breaker 1 has dropped (Yes in step S50), the control unit 11 advances the process to step S60. If it is judged that the voltage on the secondary side of the circuit breaker 1 has not dropped (No in step S50), the control unit 11 returns to step S50 and repeats the process.

When executing step S50, the control unit 11 measures the maximum current value while measuring the current value. The control unit 11 measures an R-phase current maximum value, which is the maximum R-phase current value detected by the current detection unit 14r, an S-phase current maximum value, which is the maximum S-phase current value detected by the current detection unit 14s, and a T-phase current maximum value, which is the maximum T-phase current value detected by the current detection unit 14t.

(Step S60)
The control unit 11 stops the time measurement by the timer and records the time measured by the timer as at least one of the R-phase current reference value exceeding time, the S-phase current reference value exceeding time, and the T-phase current reference value exceeding time based on the current determined in step S30.

(Step S70)
The control unit 11 then determines that the circuit breaker 1 has interrupted the electrical path by performing an instantaneous interruption operation.

(Step S80)
The control unit 11 stores the measurement results and the judgment results in the communication memory shown in Table 1. The control unit 11 records in the communication memory that it has judged the instantaneous operation. The control unit 11 also records in the communication memory that it has not judged the inverse time operation and that it has not judged the power interruption. The control unit 11 transmits the measurement results and the judgment results to the control device 5 via the communication unit 15.

(Step S110)
If it is determined in step S30 that the effective value of the current flowing through the circuit breaker 1 is smaller than the instantaneous operating current value, the control unit 11 judges whether the effective value of the current flowing through the circuit breaker 1 is greater than the interrupting operating current value. If the effective value of the current flowing through the circuit breaker 1 is greater than the interrupting operating current value (Yes in step S110), the control unit 11 advances the process to step S120. If the effective value of the current flowing through the circuit breaker 1 is equal to or less than the interrupting operating current value (No in step S110), the control unit 11 advances the process to step S210.

(Step S120)
Next, the control unit 11 starts measuring time using a timer.

(Step S130)
Next, the control unit 11 determines whether the electric path has been interrupted by the circuit breaker 1. Specifically, the control unit 11 determines whether the electric path has been interrupted by the circuit breaker 1 based on whether the voltage has dropped below a predetermined voltage.

First, the control unit 11 controls the power calculation unit 12 to measure the current and voltage. Then, the control unit 11 acquires the voltage value measured by the power calculation unit 12. Next, the control unit 11 determines whether the acquired voltage value, i.e., the voltage on the secondary side of the circuit breaker 1, has dropped. If it is determined that the voltage on the secondary side of the circuit breaker 1 has dropped (Yes in step S130), the control unit 11 proceeds to step S140. If it is determined that the voltage on the secondary side of the circuit breaker 1 has not dropped (No in step S130), the control unit 11 proceeds to step S170.

(Step S140)
The control unit 11 stops the time measurement by the timer and records the time measured by the timer as at least one of the R-phase current reference value exceeding time, the S-phase current reference value exceeding time, and the T-phase current reference value exceeding time based on the current determined in step S30.

(Step S150)
The control unit 11 then determines that the circuit breaker 1 has interrupted the electrical circuit by an inverse time operation.

(Step S160)
The control unit 11 stores the measurement results and the judgment results in the communication memory shown in Table 1. The control unit 11 records in the communication memory that it has judged the inverse time operation. The control unit 11 also records in the communication memory that it has not judged the instantaneous operation or the power interruption. The control unit 11 transmits the measurement results and the judgment results to the control device 5 via the communication unit 15.

(Step S170)
In step S130, when it is determined that the voltage on the secondary side of the circuit breaker 1 has not dropped (No in step S130), the control unit 11 determines whether the current is equal to or lower than the interruption operation current value. Specifically, the control unit 11 controls the power calculation unit 12 to measure the current and the voltage. Then, the control unit 11 acquires the current value measured by the power calculation unit 12. Next, the control unit 11 determines whether the acquired current value is equal to or lower than the interruption operation current value.

If the acquired current value is equal to or less than the cutoff operation current value (Yes in step S170), the control unit 11 proceeds to step S180. If the acquired current value is greater than the cutoff operation current value (No in step S170), the control unit 11 returns to step S130 and repeats the process.

(Step S180)
The control unit 11 then determines that the current has returned to a normal state without the circuit breaker 1 performing an interruption operation.

(Step S190)
The control unit 11 stores the measurement results and the determination results in the communication memory shown in Table 1. The control unit 11 transmits the measurement results and the determination results to the control device 5 via the communication unit 15.

(Step S210)
When the effective value of the current flowing through the circuit breaker 1 is equal to or less than the interruption operation current value (No in step S110), the control unit 11 stores the measurement results and the determination results in the communication memory shown in Table 1. Then, the control unit 11 transmits the measurement results and the determination results to the control device 5 via the communication unit 15.

In steps S190 and S210, the R-phase current value, S-phase current value, T-phase current value, UV line voltage value, VU line voltage value, and WU line voltage value are transmitted as measurement results, thereby making it possible to constantly monitor, for example, the power flowing through the circuit breaker 1.

It is also possible to determine that the power has been manually shut off (power-off determination) by determining whether the electric circuit has been shut off before step S210. If the electric circuit has been shut off before step S210, the current value of the current that was flowing immediately before is lower than the shut-off operation current value, so it can be determined that the power has been manually shut off.

<Example of Processing by Diagnostic Device 10>
A description will now be given of an example of diagnostic processing by the diagnostic device 10. Fig. 7 is a diagram illustrating the temporal operation of the processing by the diagnostic device 10 according to the first embodiment.

The upper side of Fig. 7 shows a current waveform (current waveform Im), and the lower side shows a voltage waveform (voltage waveform Vm). The vertical axis of Fig. 7 represents current value and voltage value, respectively. The horizontal axis of Fig. 7 represents time. In the example of Fig. 7, the current waveform Im is assumed to be in a range smaller than the current value Ith2, which is the instantaneous operating current value.

When the current waveform Im becomes greater than the interruption operation current value at time Ts (Yes in step S110), the diagnostic device 10 starts measuring time using a timer. Then, the circuit breaker 1 interrupts the electric circuit when a period (period T1) determined by the characteristic curve Lsp has elapsed from time Ts. When the circuit breaker 1 interrupts the electric circuit, the voltage drops at time Td. When the diagnostic device 10 determines that the voltage has dropped at time Td and that the circuit breaker 1 has interrupted the electric circuit (Yes in step S130), it stops measuring time using the timer. Then, the time measured by the timer, the maximum value Im_max of the flowing current, and the determination result that the inverse time operation has occurred are stored in a communication memory and transmitted to the control device 5.

<Action and Effects>
The diagnostic device 10 according to the first embodiment can diagnose and determine whether the circuit breaker 1 has been tripped due to an overload or a short circuit, that is, the cause of the tripping.

The control unit 11 is an example of a diagnosis unit, the current value Ith2 is an example of a first current value, and the current value Ith1 is an example of a second current value.

Second Embodiment
Although the diagnostic device 10 according to the first embodiment is a standalone device installed in the vicinity of the circuit breaker 1, the diagnostic device may be an optional unit for the circuit breaker 1.

The diagnostic device 110 according to the second embodiment is installed as an optional unit of the circuit breaker 1 .

FIG. 8 is a diagram for explaining connections of a diagnostic device 110 according to the second embodiment.

The option-equipped circuit breaker 101 includes the circuit breaker 1 and a diagnostic device 110 as an optional unit of the circuit breaker 1. That is, the diagnostic device 110 is an optional unit of the circuit breaker 1. The option-equipped circuit breaker 101 is also a circuit breaker with a diagnostic device. The diagnostic device 110 is provided on the secondary side of the circuit breaker 1.

The option-equipped circuit breaker 101 is connected to a power source 2 via a connection wiring W1 including a wiring W1r, a wiring W1s, and a wiring W1t. That is, the power source 2 is connected to the primary side of the circuit breaker 1.

Furthermore, the option-equipped circuit breaker 101 is connected to the load 3 via the diagnostic device 110. Specifically, the option-equipped circuit breaker 101 is connected to the load 3 via a connection wiring W3 including a wiring W3r, a wiring W3s, and a wiring W3t.

The functional configuration of the diagnostic device 110 is similar to that of the diagnostic device 10 .

Third Embodiment
The diagnostic device 10 in the first embodiment is installed midway along the wiring provided on the secondary side of the circuit breaker 1, but the diagnostic device may also be installed at a location away from the wiring provided on the secondary side of the circuit breaker 1.

The diagnostic device 210 according to the third embodiment is installed at a location away from the wiring provided on the secondary side of the circuit breaker 1 .

Fig. 9 is a diagram for explaining connections of the diagnostic device 210 according to the third embodiment. Fig. 10 is a functional block diagram for explaining the functional configuration of the diagnostic device 210 according to the third embodiment.

The circuit breaker 1 is connected to the power source 2 via a connection wiring W1 including a wiring W1r, a wiring W1s, and a wiring W1t. That is, the power source 2 is connected to the primary side of the circuit breaker 1.

The circuit breaker 1 is also connected to the load 3 via a connection wiring W4 including a wiring W4r, a wiring W4s and a wiring W4t.

In the diagnostic device 10 according to the first embodiment, the voltage detection unit 13r is connected to the internal wiring Lr and the internal wiring Ls, the voltage detection unit 13s is connected to the internal wiring Ls and the internal wiring Lt, and the voltage detection unit 13t is connected to the internal wiring Lt and the internal wiring Lr. Meanwhile, in the diagnostic device 210 according to the third embodiment, the voltage detection unit 13r is connected to the wiring W4r and the wiring W4s of the connection wiring W4, the voltage detection unit 13s is connected to the wiring W4s and the wiring W4t of the connection wiring W4, and the voltage detection unit 13t is connected to the wiring W4t and the wiring W4r of the connection wiring W4.

In the diagnostic device 10 according to the first embodiment, the current detection units 14r, 14s, and 14t are attached to the internal wiring Lr, internal wiring Ls, and internal wiring Lt, respectively. Meanwhile, the diagnostic device 210 according to the third embodiment includes the current detection units 214r, 214s, and 214t outside the diagnostic device 210. In the diagnostic device 210 according to the third embodiment, the current detection units 214r, 214s, and 214t are attached to the wiring W4r, wiring W4s, and wiring W4t of the connection wiring W4, respectively.

In addition, the same components as those in the diagnosis device 10 according to the first embodiment are denoted by the same reference numerals and detailed description thereof will be omitted.

Fourth Embodiment
The diagnostic device 110 in the second embodiment is installed on the secondary side of the circuit breaker 1 as an optional unit for the circuit breaker 1, but the diagnostic device may also be installed on the primary side of the circuit breaker 1 as an optional unit for the circuit breaker 1.

Fig. 11 is a diagram for explaining connections of a diagnostic device 310 according to the fourth embodiment. Fig. 12 is a functional block diagram for explaining the functional configuration of a diagnostic device 310 according to the fourth embodiment.

The option-equipped circuit breaker 301 includes the circuit breaker 1 and a diagnostic device 310 as an optional unit of the circuit breaker 1. In other words, the diagnostic device 310 is an optional unit of the circuit breaker 1. The option-equipped circuit breaker 301 is also a circuit breaker with a diagnostic device. The diagnostic device 310 is provided on the primary side of the circuit breaker 1.

The option-equipped circuit breaker 301 is connected to the power source 2 via a diagnostic device 310. The option-equipped circuit breaker 301 is connected to the power source 2 via a connection wiring W1 including a wiring W1r, a wiring W1s, and a wiring W1t. That is, the power source 2 is connected to the primary side of the circuit breaker 1.

Furthermore, the option-equipped circuit breaker 301 is connected to the load 3 via a connection wiring W4 that includes a wiring W4r, a wiring W4s, and a wiring W4t.

In the diagnostic device 110 according to the second embodiment, the voltage detection unit 13r is connected to the internal wiring Lr and the internal wiring Ls, the voltage detection unit 13s is connected to the internal wiring Ls and the internal wiring Lt, and the voltage detection unit 13t is connected to the internal wiring Lt and the internal wiring Lr. Meanwhile, in the diagnostic device 310 according to the fourth embodiment, the voltage detection unit 13r is connected to the wiring W4r and the wiring W4s of the connection wiring W4, the voltage detection unit 13s is connected to the wiring W4s and the wiring W4t of the connection wiring W4, and the voltage detection unit 13t is connected to the wiring W4t and the wiring W4r of the connection wiring W4.

In addition, the same components as those in the diagnosis device 10 according to the first embodiment are denoted by the same reference numerals and detailed description thereof will be omitted.

Fifth embodiment
The diagnostic device 110 according to the second embodiment is installed on the secondary side of the circuit breaker 1 as an optional unit of the circuit breaker 1. Moreover, the diagnostic device 310 according to the fourth embodiment is installed on the primary side of the circuit breaker 1 as an optional unit of the circuit breaker 1. On the other hand, the diagnostic device may be installed as an optional unit of the circuit breaker 1 at a location different from the primary and secondary sides of the circuit breaker 1.

FIG. 13 is a diagram for explaining connections of a diagnostic device 410 according to the fifth embodiment.

The option-equipped circuit breaker 401 includes the circuit breaker 1 and a diagnostic device 410 as an optional unit of the circuit breaker 1. In other words, the diagnostic device 410 is an optional unit of the circuit breaker 1. The option-equipped circuit breaker 401 is also a circuit breaker with a diagnostic device. The diagnostic device 410 is provided on the side of the circuit breaker 1.

The option-equipped circuit breaker 401 is connected to the power source 2 via a connection wiring W1 including a wiring W1r, a wiring W1s, and a wiring W1t. That is, the power source 2 is connected to the primary side of the circuit breaker 1.

Furthermore, the option-equipped circuit breaker 401 is connected to the load 3 via a connection wiring W4 that includes a wiring W4r, a wiring W4s, and a wiring W4t.

In the diagnostic device 410 of the fifth embodiment, the voltage detection unit 13r is connected to the R-phase wiring and S-phase wiring inside the circuit breaker 1, the voltage detection unit 13s is connected to the S-phase wiring and T-phase wiring inside the circuit breaker 1, and the voltage detection unit 13t is connected to the T-phase wiring and R-phase wiring inside the circuit breaker 1.

The diagnostic device 410 according to the fifth embodiment includes a current detection unit 414r, a current detection unit 414s, and a current detection unit 414t that are external to the diagnostic device 410. In the diagnostic device 410 according to the fifth embodiment, the current detection unit 414r, the current detection unit 414s, and the current detection unit 414t are attached to the wiring W4r, the wiring W4s, and the wiring W4t of the connection wiring W4, respectively.

In addition, the same components as those in the diagnosis device 10 according to the first embodiment are denoted by the same reference numerals and detailed description thereof will be omitted.

Sixth Embodiment
In the diagnostic device 10 according to the first embodiment, the control unit 11 detects a drop in the secondary side voltage, but it is not limited to the control unit 11 that detects a drop in the secondary side voltage.

FIG. 14 is a functional block diagram illustrating the functional configuration of a diagnostic device 510 according to the sixth embodiment.

The diagnostic device 510 further comprises a voltage drop detection circuit 516 in comparison with the diagnostic device 10. And, the diagnostic device 510 comprises a control unit 511 instead of the control unit 11 of the diagnostic device 10.

The voltage drop detection circuit 516 detects a voltage drop based on signals from the voltage detection units 13r, 13s, and 13t, and notifies the control unit 511. The control unit 511 determines that the voltage on the secondary side has dropped based on the detection result from the voltage drop detection circuit 516.

In addition, the same components as those in the diagnosis device 10 according to the first embodiment are denoted by the same reference numerals and detailed description thereof will be omitted.

Seventh embodiment
The diagnostic device 10 according to the first embodiment starts a timer and starts a diagnosis when the current value is greater than a predetermined threshold value in steps S30 and S110, for example. The start of diagnosis in the diagnostic device is not limited to monitoring the current. The diagnostic device may start diagnosis by monitoring the voltage.

Fig. 15 is a diagram for explaining the temporal operation of the processing of the diagnostic device according to the seventh embodiment. The upper side of Fig. 15 shows a current waveform (current waveform Im2), and the lower side shows a voltage waveform (voltage waveform Vm2). The vertical axis of Fig. 15 represents the current value and the voltage value, respectively. The horizontal axis of Fig. 15 represents time. In the example of Fig. 15, the current waveform Im2 is assumed to be in a range smaller than the current value Ith2, which is the instantaneous operating current value.

For example, when the voltage waveform Vm2 drops at time Td2, a determination may be made based on the current value in a period T2 immediately before time Td2.

In order to store the current value immediately before time Td2, the current value may be measured continuously and the measurement results may be stored in memory, and when the voltage waveform Vm2 drops, the current value stored in memory may be read out to measure the current value for period T2.

Eighth embodiment
The diagnostic device 10 according to the first embodiment judges whether the inverse time cutting operation is performed and whether the instantaneous cutting operation is performed. However, the items to be judged are not limited to whether the inverse time cutting operation is performed and whether the instantaneous cutting operation is performed.

16 is a diagram for explaining the diagnosis of a circuit breaker performed by the diagnosis device according to the eighth embodiment. For example, a current value Ith12 that is greater than the current value Ith1 and less than the current value Ith2 may be set. That is, a case in which the current value of the current flowing through the circuit breaker 1 is greater than the current value Ith1 and equal to or less than the current value Ith12 (first inverse time operation condition Ct11) and a case in which the current value is greater than the current value Ith12 and less than the current value Ith2 (second inverse time operation condition Ct12) may be provided.

Then, when the current value is greater than current value Ith12 and less than current value Ith2 (second inverse time operation condition Ct12), the diagnostic device may determine that the current range requires maintenance, for example.

Although FIG. 16 shows one current value as the current value that can be newly set, the current value that can be newly set is not limited to one, and two or more set values may be provided.

The result of determining that the current value is greater than current value Ith12 and less than current value Ith2 may be stored, for example, as user-defined determination A or user-defined determination B in the communication memory.

It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims.

This application claims priority to basic patent application No. 2021-126920, filed on August 2, 2021, with the Japan Patent Office, the entire contents of which are incorporated herein by reference.

1 Circuit breaker 101, 301, 401 Circuit breaker with option 1a Operation lever 2 Power source 3 Load 5 Control device 10, 110, 210, 310, 410, 510 Diagnosis device 11, 511 Control unit 12 Power calculation unit 13r, 13s, 13t Voltage detection unit 14r, 14s, 14t Current detection unit 15 Communication unit 214r, 214s, 214t, 414r, 414s, 414t Current detection unit 516 Voltage drop detection circuit Lr, Ls, Lt Internal wiring W1, W2, W3, W4 Connection wiring W1r, W1s, W1t Wiring W2r, W2s, W2t Wiring W3r, W3s, W3t Wiring W4r, W4s, W4t Wiring

Claims (5)

a current detection unit that measures a current value of a current flowing through the circuit breaker;
A voltage detection unit that measures a voltage value of a secondary side voltage of the circuit breaker;
a diagnosis unit that diagnoses a cause of an interruption when the circuit breaker is interrupted based on the current value measured by the current detection unit;
Equipped with
the diagnosing unit diagnoses the cause of the interruption based on the current value immediately before the voltage value measured by the voltage detecting unit drops .
Diagnostic equipment. The diagnosis unit diagnoses that the circuit breaker has been opened due to a short circuit when the current value is equal to or greater than a first current value.
The diagnostic device of claim 1 . The diagnosis unit diagnoses that the circuit breaker has been tripped due to an overload when the current value is greater than a second current value that is smaller than the first current value and the current value is smaller than the first current value.
The diagnostic device of claim 2. A circuit breaker;
The diagnostic device according to any one of claims 1 to 3 , which diagnoses the circuit breaker.
Circuit breaker with diagnostics. (a) measuring the current value of a current through a circuit breaker;
(b) measuring a voltage value of a secondary voltage of the circuit breaker;
( c ) when the voltage value measured in the step (b) drops, diagnosing a cause of the circuit breaker being tripped based on the current value measured in the immediately preceding step (a);
including,
Diagnostic methods.

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