Circuit breaker with insulation monitoring function

Abstract

To provide an insulation monitoring system which can appropriately monitor deterioration of insulation of a cable way.SOLUTION: An insulation monitoring system 50 includes: a circuit breaker 2 including a switching contact 4 provided in a cable way 1; a zero-phase-sequence current transformer 8 for detecting leakage current of the cable way 1; a leakage current measuring part 10 for measuring a value of the leakage current of the cable way 1 based on a detection signal from the zero-phase-sequence current transformer 8; and a determination part 19 for performing insulation monitoring based on the value of the leakage current, which is measured by the leakage current measuring part 10 when the switching contact 4 is closed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an insulation monitoring system and a circuit breaker with insulation monitoring function that detect leakage current and monitor the insulation state of an electric circuit. [Background technology]

[0002] Conventional earth leakage circuit breakers are known to detect leakage current and monitor the insulation state of an electric circuit in order to prevent load equipment failures and fire accidents caused by leakage current. Also, techniques are known that use average or cumulative values ​​of leakage current to grasp the deterioration trend of insulation in an electric circuit. Patent Document 1 discloses an overcurrent detection device that detects fault currents in an electric circuit to enable optimal protection. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 113617 / 1983 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional earth leakage circuit breakers, the leakage current when the circuit breaker is on differs from the leakage current when the circuit breaker is off, so the calculation of the average leakage current and the cumulative leakage current is affected by the circuit breaker's state. Furthermore, the leakage current when the power supply upstream of the circuit breaker is turned off differs from the leakage current when the operation of the load equipment downstream of the circuit breaker is stopped, so the calculation of the average leakage current and the cumulative leakage current is affected by these two cases. When a power outage continues for a long period of time or when the operation of the load equipment is stopped, the average leakage current and the cumulative leakage current are significantly affected, so conventional technology has the problem of making it difficult to grasp the deterioration trend of the circuit insulation.

[0005] The present disclosure has been made in view of the above, and aims to provide an insulation monitoring system that can appropriately monitor the deterioration of insulation in an electrical circuit. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, Circuit breaker with insulation monitoring function teeth, internal Switching contacts installed in the circuit Dots and , internal A zero-phase current transformer detects leakage current in the electrical circuit, and a detection signal from the zero-phase current transformer is used. internal The leakage current measurement unit measures the value of the leakage current in the circuit, and the leakage current measured by the leakage current measurement unit when the switching contact is closed. internal A judgment unit that monitors the insulation of the electrical circuit a voltage measurement unit that measures the voltage of any two of a plurality of electric circuits that constitute an internal electric circuit on the load side of the switching contact; and a calculation unit that determines that the switching contact is closed when it is determined that the value of the voltage measured by the voltage measurement unit is higher than a predetermined value. The present invention is characterized by having the following. [Effects of the Invention]

[0007] The insulation monitoring system according to the present disclosure has the advantage of being able to appropriately monitor the deterioration of insulation in an electrical circuit. [Brief explanation of the drawings]

[0008] [Figure 1] Block diagram showing the configuration of an insulation monitoring system according to the first embodiment. [Figure 2] 1 is a flowchart showing the procedure of processing performed by an average value calculation unit, a determination unit, and an alarm output unit included in the insulation monitoring system according to the first embodiment. [Figure 3] FIG. 1 is a diagram for explaining an average value of leakage current and a cumulative value of leakage current in the first embodiment. [Figure 4] 1 is a flowchart showing the procedure of processing performed by an accumulated value calculation unit, a determination unit, a display unit, and an alarm output unit included in the insulation monitoring system according to the first embodiment. [Figure 5] A block diagram showing the configuration of a circuit breaker with insulation monitoring function according to a second embodiment. [Figure 6] A block diagram showing the configuration of a circuit breaker with insulation monitoring function according to a third embodiment. [Figure 7] 10 is a flowchart showing the procedure of operations performed by an average value calculation unit, a determination unit, and an alarm output unit included in a circuit breaker with insulation monitoring function according to a third embodiment. [Figure 8] 10 is a flowchart showing the procedure of processing performed by an accumulated value calculation unit, a determination unit, a display unit, and an alarm output unit included in a circuit breaker with insulation monitoring function according to a third embodiment. [Figure 9] FIG. 1 is a diagram showing a processor in a case where some or all of the functions of a contact opening / closing detector, a trip device, and an auxiliary contact output unit included in a circuit breaker of an insulation monitoring system according to the first embodiment are realized by the processor. [Figure 10] FIG. 1 is a diagram showing a processing circuit in the case where some or all of the functions of the contact opening / closing detector, trip device, and auxiliary contact output unit of the circuit breaker of the insulation monitoring system according to the first embodiment are realized by the processing circuit. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An insulation monitoring system and a circuit breaker with insulation monitoring function according to an embodiment will be described in detail below with reference to the accompanying drawings.

[0010] Embodiment 1 Fig. 1 is a block diagram showing the configuration of an insulation monitoring system 50 according to embodiment 1. As shown in Fig. 1, the insulation monitoring system 50 includes a circuit breaker 2 provided in an electric circuit 1, a communication terminal 13 connected to the circuit breaker 2, a leakage current detection device 9 that measures the leakage current of the electric circuit 1, a network 14 to which the communication terminal 13 and the leakage current detection device 9 are connected, and an electric leakage determination device 15 that determines whether the leakage current measured by the leakage current detection device 9 is abnormal. The electric leakage determination device 15 is connected to the network 14.

[0011] The circuit breaker 2 has a power supply side terminal 3a and a load side terminal 3b. The power supply side terminal 3a is connected to a power supply, and the load side terminal 3b is connected to a load 12. The circuit breaker 2 further has a switching contact 4 provided between the power supply side terminal 3a and the load side terminal 3b. The switching contact 4 is provided on the electric circuit 1. The circuit breaker 2 further has a contact switching detection unit 5 that detects the open / closed state of the switching contact 4, a trip device 6 that trips the switching contact 4, and an auxiliary contact output unit 7 that outputs a signal indicating the state detected by the contact switching detection unit 5 to a communication terminal 13.

[0012] The communication terminal 13 receives the signal output from the auxiliary contact output unit 7 and transmits information indicating the open / closed state of the switch contact 4 to the earth leakage determination device 15 via the network 14. The insulation monitoring system 50 further includes a zero-phase-sequence current transformer 8 that is provided in the electric circuit 1 and detects the leakage current of the electric circuit 1. The leakage current detection device 9 includes a leakage current measurement unit 10 to which a detection signal from the zero-phase-sequence current transformer 8 is input. The leakage current measurement unit 10 measures the value of the leakage current of the electric circuit 1 based on the detection signal from the zero-phase-sequence current transformer 8. The leakage current detection device 9 further includes a communication processing unit 11 that transmits information indicating the value of the leakage current measured by the leakage current measurement unit 10 to the earth leakage determination device 15 via the network 14.

[0013] The leakage current determination device 15 has a communication processing unit 16 that receives various signals via the network 14, an average value calculation unit 17 that calculates an average value of the leakage current, which is the average per predetermined time of the leakage current values ​​of the circuit 1 measured by the leakage current measurement unit 10 of the leakage current detection device 9, and an accumulated value calculation unit 18 that calculates an accumulated value of the leakage current, which is the accumulation of the leakage current values ​​of the circuit 1 measured by the leakage current measurement unit 10.

[0014] The earth leakage determination device 15 further includes a determination unit 19 that monitors the insulation of the electric circuit 1 based on the value of the leakage current measured by the leakage current measurement unit 10 when the switching contact 4 is closed. Specifically, the determination unit 19 determines whether an earth leakage has occurred based on the average value of the leakage current obtained by the average value calculation unit 17 or the accumulated value of the leakage current obtained by the accumulated value calculation unit 18. The earth leakage determination device 15 further includes a display unit 20 that displays the average value of the leakage current and the accumulated value of the leakage current, and an alarm output unit 21 that outputs an alarm when the determination unit 19 determines that an earth leakage has occurred. For example, the display unit 20 is realized by a liquid crystal display device.

[0015] FIG. 2 is a flowchart showing the processing steps performed by the average value calculation unit 17, the determination unit 19, and the alarm output unit 21 of the insulation monitoring system 50 according to the first embodiment. FIG. 3 is a diagram illustrating the average value of the leakage current and the cumulative value of the leakage current according to the first embodiment. The average value of the leakage current is the average of the leakage current values ​​over an average time period. The average time period of the leakage current is a value set, for example, between 0 and 15 minutes. In FIG. 3, it is assumed that the average time period is 15 minutes. FIG. 3 shows how (A) the open / close state of the switching contact 4 of the circuit breaker 2, (B) the detected value of the leakage current, (C) the moving average value of the leakage current, (D) the average value of the leakage current, and (E) the cumulative value of the leakage current change over time. In FIG. 3, "OFF" indicates that the switching contact 4 is open, and "ON" indicates that the switching contact 4 is closed. (D) The average value of the leakage current indicates that the average is applied when the switching contact 4 is open. (E) The cumulative value of leakage current is shown for the first embodiment and for the conventional case. (E) Some of the cumulative values ​​of leakage current for the first embodiment are indicated by dashed lines.

[0016] The average value calculation unit 17 repeatedly performs the process shown in Fig. 2 at predetermined time intervals. As shown in Fig. 2, the average value calculation unit 17 acquires information indicating the value of the leakage current from the leakage current measurement unit 10 (S1). Next, the average value calculation unit 17 acquires information indicating the state of the switching contacts 4 from the auxiliary contact output unit 7 via the communication processing unit 16 (S2). In Fig. 2, the operation of step S2 is indicated by the phrase "acquire circuit breaker contact information."

[0017] The average value calculation unit 17 determines whether the switch contact 4 is closed (S3). In FIG. 2, the operation of step S3 is indicated by the words "contact ON?". If the average value calculation unit 17 determines that the switch contact 4 is open (No in S3), it does not use the leakage current value indicated by the information acquired in step S1, and sets the value of the leakage current measured previously as the value of the leakage current measured this time (S4). The average value calculation unit 17 performs the operation of step S5 after the operation of step S4. If the average value calculation unit 17 determines that the switch contact 4 is closed (Yes in S3), it performs the operation of step S5 after the operation of step S3. In step S5, the average value calculation unit 17 calculates the average value of the leakage current based on the set averaging time limit.

[0018] Next, the determination unit 19 determines whether the average value of the leakage current calculated in step S5 is greater than a predetermined threshold value (S6). If the determination unit 19 determines that the average value is greater than the threshold value (Yes in S6), it determines that a leakage current has occurred, and the alarm output unit 21 outputs an alarm (S7). If the determination unit 19 determines that the average value of the leakage current is equal to or less than the threshold value (No in S6), the process ends.

[0019] 4 is a flowchart showing the procedure of processing performed by the cumulative value calculation unit 18, determination unit 19, display unit 20, and alarm output unit 21 of the insulation monitoring system 50 according to the first embodiment. As shown in FIG. 4, the cumulative value calculation unit 18 acquires information indicating the open / closed state of the switching contacts 4 from the contact open / close detection unit 5 (S11). In FIG. 4, the operation of step S11 is indicated by the phrase "acquire circuit breaker contact information." Next, the cumulative value calculation unit 18 determines whether the switching contacts 4 are closed based on the information acquired in step S11 (S12). In FIG. 4, the operation of step S12 is indicated by the phrase "contacts ON?"

[0020] If the cumulative value calculation unit 18 determines that the switching contact 4 is closed (Yes in S12), it acquires information indicating the value of the leakage current from the leakage current measurement unit 10 (S13). After performing the operation of step S13, the cumulative value calculation unit 18 performs the operation of step S17. If the cumulative value calculation unit 18 determines that the switching contact 4 is open (No in S12), it determines whether the switching contact 4 was closed at the time of the previous processing (S14). In FIG. 4, the operation of step S14 is indicated by the phrase "Previous contact ON?"

[0021] If the cumulative value calculation unit 18 determines that the switch contact 4 was closed during the previous processing (Yes in S14), it sets the average value of the leakage current calculated in step S5 of FIG. 2 as the value of the leakage current (S15). After performing the operation of step S15, the cumulative value calculation unit 18 performs the operation of step S17. If the cumulative value calculation unit 18 determines that the switch contact 4 was open during the previous processing (No in S14), it determines that the switch contact 4 was open both last time and this time, and the average value of the leakage current has already been set, so it sets the value of the leakage current used during the previous processing as the value of the leakage current (S16). After performing the operation of step S16, the cumulative value calculation unit 18 performs the operation of step S17.

[0022] In step S17, the cumulative value calculation unit 18 calculates the cumulative value of the leakage current using one of the leakage current value indicated by the information acquired in step S13, the leakage current value set in step S15, and the leakage current value set in step S16. The determination unit 19 determines whether the cumulative value of the leakage current calculated in step S17 is greater than a predetermined threshold value (S18).

[0023] If the judgment unit 19 judges that the accumulated value is greater than the threshold value (Yes in S18), it judges that deterioration of insulation has occurred. The display unit 20 displays information indicating the alarm, and the alarm output unit 21 outputs the alarm by email notification or the like (S19). The alarm output unit 21 outputs the alarm to the communication terminal 13 via the network 14. The switching contacts 4 may be tripped by the communication terminal 13 driving the trip device 6. After the operation of step S19 is performed, the operation of step S20 is performed. If the judgment unit 19 judges that the accumulated value is equal to or less than the threshold value (No in S18), it performs the operation of step S20.

[0024] In step S20, the determination unit 19 determines whether the accumulated time, which is the operating time of the electric leakage determination device, is longer than a predetermined set value (S20). The set value for the accumulated time is, for example, one month. If the determination unit 19 determines that the accumulated time is longer than the set value (Yes in S20), it resets the accumulated value and the accumulated time (S21). If the determination unit 19 determines that the accumulated time is equal to or less than the set value (No in S20), the processing ends. The accumulated value is periodically reset. The above processing is repeated for each sampling period. In steps S20 and S21, the accumulated value and the accumulated time are reset periodically (for example, once a month) even when no alarm is output, so that the accumulated value of the leakage current determined in step S18 is the accumulated value for one month.

[0025] The insulation monitoring system 50 according to the first embodiment includes a determination unit 19 that performs insulation monitoring based on leakage current when a voltage is applied to the electric circuit 1, and therefore can more accurately grasp the tendency of insulation deterioration. In other words, the insulation monitoring system 50 can appropriately monitor the insulation deterioration of the electric circuit 1. According to the first embodiment, the communication terminal 13 and the leakage current detection device 9 are provided separately from the circuit breaker 2, so that a general-purpose circuit breaker without communication capabilities can be used as the circuit breaker 2. According to the first embodiment, the insulation monitoring system 50 can also be constructed by connecting the communication terminal 13 and the leakage current detection device 9 to an existing circuit breaker 2.

[0026] Embodiment 2 5 is a block diagram showing the configuration of a circuit breaker 2A with insulation monitoring function according to the second embodiment. Hereinafter, the "circuit breaker 2A with insulation monitoring function" may be referred to as circuit breaker 2A. The circuit breaker 2A has the power supply side terminal 3a, load side terminal 3b, switching contacts 4, contact switching detection unit 5, and trip device 6 that the circuit breaker 2 of the first embodiment has. The circuit breaker 2A further has a zero-phase current transformer 8A, a leakage current measurement unit 10A, an average value calculation unit 17A, an accumulated value calculation unit 18A, a determination unit 19A, a display unit 20, and an alarm output unit 21. Zero-phase-sequence current transformer 8A has a function equivalent to that of zero-phase-sequence current transformer 8 of embodiment 1, leakage current measuring unit 10A has a function equivalent to that of leakage current measuring unit 10 of embodiment 1, average value calculation unit 17A has a function equivalent to that of average value calculation unit 17 of embodiment 1, cumulative value calculation unit 18A has a function equivalent to that of cumulative value calculation unit 18 of embodiment 1, and judgment unit 19A has a function equivalent to that of judgment unit 19 of embodiment 1. In embodiment 2, differences from embodiment 1 will mainly be described.

[0027] The zero-phase current transformer 8A detects leakage current in the internal electric circuit 22. The internal electric circuit 22 is an electric circuit inside the circuit breaker 2A. The leakage current measuring unit 10A measures the value of the leakage current in the internal electric circuit 22 based on the detection signal from the zero-phase current transformer 8A. The average value calculating unit 17A calculates the average value of the leakage current, which is the average per predetermined time of the values ​​of the leakage current in the internal electric circuit 22 measured by the leakage current measuring unit 10A. The cumulative value calculating unit 18A calculates the cumulative value of the leakage current, which is the cumulative value of the values ​​of the leakage current in the internal electric circuit 22 measured by the leakage current measuring unit 10A. The judgment unit 19A monitors the insulation of the internal electric circuit 22 based on the value of the leakage current measured by the leakage current measuring unit 10A when the switching contact 4 is closed. Specifically, the judgment unit 19A judges whether or not a leakage current has occurred based on the average value of the leakage current obtained by the average value calculation unit 17A or the cumulative value of the leakage current obtained by the cumulative value calculation unit 18A.

[0028] In the second embodiment, information indicating the value of the leakage current of the internal electric circuit 22 measured by the leakage current measuring unit 10A is received by the determining unit 19A. The determining unit 19A is connected to the trip device 6. This allows the circuit breaker 2A to realize the functions of a normal earth leakage circuit breaker.

[0029] The circuit breaker 2A according to the second embodiment has a determination unit 19A that performs insulation monitoring based on leakage current when a voltage is applied to the internal electric circuit 22. Therefore, the circuit breaker 2A can more accurately grasp the tendency of insulation deterioration.

[0030] Embodiment 3 FIG. 6 is a block diagram showing the configuration of a circuit breaker 2B with insulation monitoring function according to embodiment 3. Hereinafter, the "circuit breaker 2B with insulation monitoring function" may be referred to as circuit breaker 2B. The circuit breaker 2B has a voltage measurement unit 24 and a current measurement unit 26 instead of the contact opening / closing detection unit 5 that the circuit breaker 2A according to embodiment 2 has. In embodiment 3, differences from embodiment 2 will be mainly described.

[0031] As shown in FIG. 6 , the circuit breaker 2B has a voltage detection terminal 23 provided on the internal electric circuit 22 and a voltage measurement unit 24 connected to the voltage detection terminal 23. The voltage measurement unit 24 measures the voltage of any two of the multiple electric circuits constituting the internal electric circuit 22 on the load side of the switching contact 4. The circuit breaker 2B further has multiple current sensors 25 provided on the internal electric circuit 22 to detect the current of any one of the multiple electric circuits constituting the internal electric circuit 22, and a current measurement unit 26 connected to the current sensors 25 to measure the current of each electric circuit. The circuit breaker 2B further has the power supply side terminal 3a, the load side terminal 3b, the switching contact 4, the trip device 6, the zero-phase current transformer 8A, the leakage current measurement unit 10A, the display unit 20, and the alarm output unit 21 provided in the circuit breaker 2A according to the second embodiment. The circuit breaker 2B further has an average value calculation unit 17B, an accumulated value calculation unit 18B, and a determination unit 19B.

[0032] Information indicating the voltage value between any two electrical circuits constituting the internal electrical circuit 22, measured by the voltage measurement unit 24, and information indicating the current values ​​of each of the multiple electrical circuits constituting the internal electrical circuit 22, measured by the current measurement unit 26, are received by the average value calculation unit 17B and the cumulative value calculation unit 18B. Information indicating the leakage current value of the internal electrical circuit 22, measured by the leakage current measurement unit 10A, is also received by the average value calculation unit 17B and the cumulative value calculation unit 18B. The average value calculation unit 17B calculates the average leakage current value, which is the average of the leakage current values ​​measured by the leakage current measurement unit 10A per predetermined time period. The cumulative value calculation unit 18B calculates the cumulative leakage current value, which is the accumulation of the leakage current values ​​measured by the leakage current measurement unit 10A. The judgment unit 19B monitors the insulation of the internal electrical circuit 22 based on the leakage current value measured by the leakage current measurement unit 10A when the switching contact 4 is closed. Specifically, the judgment unit 19B judges whether or not a leakage current has occurred based on the average value of the leakage current obtained by the average value calculation unit 17B or the cumulative value of the leakage current obtained by the cumulative value calculation unit 18B.

[0033] Next, the operations of the average value calculation unit 17B, the cumulative value calculation unit 18B, and the determination unit 19B will be described. Fig. 7 is a flowchart showing the procedure of the operations performed by the average value calculation unit 17B, the determination unit 19B, and the alarm output unit 21 of the circuit breaker with insulation monitoring function 2B according to the third embodiment. As shown in Fig. 6, the average value calculation unit 17B acquires information indicating the value of the leakage current from the leakage current measurement unit 10A (S21). Next, the average value calculation unit 17B acquires information indicating the value of the voltage from the voltage measurement unit 24 (S22).

[0034] The average value calculation unit 17B determines whether the voltage value indicated by the information acquired from the voltage measurement unit 24 is higher than a predetermined value (S23). The voltage value indicated by the information acquired from the voltage measurement unit 24 is the voltage value measured by the voltage measurement unit 24. In FIG. 7, the operation of step S23 is indicated by the phrase "Voltage value > predetermined value?". If the average value calculation unit 17B determines that the voltage value indicated by the information acquired from the voltage measurement unit 24 is equal to or lower than the predetermined value (No in S23), it determines that the switching contact 4 is open (S24). In FIG. 7, the operation of step S24 is indicated by the phrase "Determine switching contact OFF." Since the average value calculation unit 17B determined that the switching contact 4 is open in step S24, it does not use the leakage current value indicated by the information acquired in step S21, and sets the value of the leakage current measured previously as the value of the leakage current measured this time (S25). After the operation of step S25, the average value calculation unit 17B performs the operation of step S27.

[0035] When the average value calculation unit 17B determines that the voltage value indicated by the information acquired from the voltage measurement unit 24 is higher than the predetermined value (Yes in S23), it determines that the switching contact 4 is closed (S26). As described above, the voltage value indicated by the information acquired from the voltage measurement unit 24 is the voltage value measured by the voltage measurement unit 24. In FIG. 7, the operation of step S26 is indicated by the phrase "determine that the switching contact is ON." After the operation of step S26, the average value calculation unit 17B performs the operation of step S27. In step S27, the average value calculation unit 17B calculates the average value of the leakage current based on a preset averaging time limit.

[0036] Next, the determination unit 19B determines whether the average value of the leakage current calculated in step S27 is greater than a predetermined threshold value (S28). If the determination unit 19B determines that the average value is greater than the threshold value (Yes in S28), it determines that a leakage current has occurred, and the alarm output unit 21 outputs an alarm (S29). If the determination unit 19B determines that the average value is equal to or less than the threshold value (No in S28), the process ends.

[0037] 8 is a flowchart showing the procedure of processing performed by the accumulated value calculation unit 18B, the determination unit 19B, the display unit 20, and the alarm output unit 21 of the circuit breaker with insulation monitoring function 2B according to the third embodiment. As shown in FIG. 8, the accumulated value calculation unit 18B acquires information indicating a voltage value from the voltage measurement unit 24 (S31). The accumulated value calculation unit 18B determines whether the voltage value indicated by the information acquired from the voltage measurement unit 24 is higher than a predetermined value (S32). In FIG. 8, the operation of step S32 is indicated by the phrase "Voltage value>predetermined value?"

[0038] If the cumulative value calculation unit 18B determines that the voltage value indicated by the information acquired from the voltage measurement unit 24 is higher than a predetermined value (Yes in S32), it determines that the switching contact 4 is closed (S33). In FIG. 8, the operation of step S33 is indicated by the phrase "determine that the switching contact is ON." The cumulative value calculation unit 18B acquires information indicating the value of the leakage current from the leakage current measurement unit 10A (S34). After performing the operation of step S34, the cumulative value calculation unit 18B performs the operation of step S39.

[0039] When cumulative value calculation unit 18B determines that the voltage value indicated by the information acquired from voltage measurement unit 24 is equal to or less than a predetermined value (No in S32), it determines that switch contact 4 is open (S35). In FIG. 8, the operation of step S35 is indicated by the phrase "determine switch contact OFF." Cumulative value calculation unit 18B determines whether the voltage value measured by voltage measurement unit 24 during the previous processing is higher than a predetermined value (S36). In FIG. 8, the operation of step S36 is indicated by the phrase "previous voltage value>predetermined value?"

[0040] If cumulative value calculation unit 18B determines that the voltage value measured by voltage measurement unit 24 during the previous processing is higher than the predetermined value (Yes in S36), it sets the average value of the leakage current calculated in step S27 of FIG. 7 as the value of the leakage current (S37). After performing the operation of step S37, cumulative value calculation unit 18B performs the operation of step S39. If cumulative value calculation unit 18B determines that the voltage value measured by voltage measurement unit 24 during the previous processing is equal to or lower than the predetermined value (No in S36), it sets the value of the leakage current used during the previous processing as the value of the leakage current (S38). After performing the operation of step S38, cumulative value calculation unit 18B performs the operation of step S39.

[0041] In step S39, cumulative value calculation unit 18B calculates the cumulative value of the leakage current using one of the leakage current value indicated by the information acquired in step S34, the leakage current value set in step S37, and the leakage current value set in step S28. Determination unit 19B determines whether the cumulative value of the leakage current calculated in step S39 is greater than a predetermined threshold value (S40).

[0042] When the judgment unit 19B judges that the cumulative value is greater than the threshold value (Yes in S40), it judges that deterioration of insulation has occurred. The display unit 20 displays information indicating the warning, and the warning output unit 21 outputs the warning by email notification or the like (S41). The judgment unit 19B may drive the trip device 6 to trip the switching contacts 4. After the operation of step S41 is performed, the operation of step S42 is performed.

[0043] If the determination unit 19B determines that the accumulated value is equal to or less than the threshold value (No in S40), it performs the operation of step S42. In step S42, the determination unit 19B determines whether the accumulated time, which is the operating time of the electric leakage determination device, is longer than a predetermined set value (S42). The set value of the accumulated time is, for example, one month. If the determination unit 19B determines that the accumulated time is longer than the set value (Yes in S42), it resets the accumulated value and the accumulated time (S43). If the determination unit 19B determines that the accumulated time is equal to or less than the set value (No in S42), the processing ends. The accumulated value is periodically reset. The above processing is repeated for each sampling period. According to steps S42 and S43, the accumulated value and the accumulated time are reset periodically (for example, once a month) even when no alarm is output, so that the accumulated value of the leakage current determined in step S40 is the accumulated value for one month.

[0044] As described above, the circuit breaker with insulation monitoring function 2B according to the third embodiment has a voltage measurement unit 24 instead of the contact opening / closing detection unit 5. The average value calculation unit 17B and the cumulative value calculation unit 18B determine whether the switching contact 4 is closed or open based on the voltage value measured by the voltage measurement unit 24. The circuit breaker 2B has a current measurement unit 26 instead of the contact opening / closing detection unit 5. The average value calculation unit 17B and the cumulative value calculation unit 18B may determine whether the switching contact 4 is closed or open based on the current value measured by the current measurement unit 26. For example, the average value calculation unit 17B and the cumulative value calculation unit 18B may determine that the switching contact 4 is closed when the current value measured by the current measurement unit 26 is greater than a predetermined value, and may determine that the switching contact 4 is open when the current value measured by the current measurement unit 26 is equal to or less than the predetermined value.

[0045] As described above, the circuit breaker with insulation monitoring function 2B according to the third embodiment has the voltage measurement unit 24 and the current measurement unit 26, and the average value calculation unit 17B and the cumulative value calculation unit 18B determine whether the switching contact 4 is closed or open based on the values ​​measured by the voltage measurement unit 24 or the current measurement unit 26. The determination unit 19B monitors the insulation based on the leakage current when a voltage is applied to the internal electric circuit 22. Therefore, the circuit breaker 2B according to the third embodiment can more accurately grasp the tendency of insulation deterioration.

[0046] 9 is a diagram showing a processor 91 when some or all of the functions of the contact opening / closing detection unit 5, trip device 6, and auxiliary contact output unit 7 of the circuit breaker 2 of the insulation monitoring system 50 according to the first embodiment are realized by the processor 91. In other words, some or all of the functions of the contact opening / closing detection unit 5, trip device 6, and auxiliary contact output unit 7 may be realized by the processor 91 executing a program stored in a memory 92. The processor 91 is a CPU (Central Processing Unit), a processing system, an arithmetic system, a microprocessor, or a DSP (Digital Signal Processor). The memory 92 is also shown in FIG.

[0047] When some or all of the functions of the contact opening / closing detection unit 5, the trip device 6, and the auxiliary contact output unit 7 are realized by the processor 91, the functions are realized by the processor 91 and software, firmware, or a combination of software and firmware. The software or firmware is written as a program and stored in the memory 92. The processor 91 realizes some or all of the functions of the contact opening / closing detection unit 5, the trip device 6, and the auxiliary contact output unit 7 by reading and executing the program stored in the memory 92.

[0048] When some or all of the functions of the contact opening / closing detection unit 5, the trip device 6, and the auxiliary contact output unit 7 are realized by the processor 91, the circuit breaker 2 has a memory 92 for storing a program that results in the execution of some or all of the steps executed by the contact opening / closing detection unit 5, the trip device 6, and the auxiliary contact output unit 7. It can also be said that the program stored in the memory 92 causes a computer to execute at least some of the procedures or methods executed by the contact opening / closing detection unit 5, the trip device 6, and the auxiliary contact output unit 7.

[0049] The memory 92 may be, for example, a non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (registered trademark) (Electrically Erasable Programmable Read-Only Memory), a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, or a DVD (Digital Versatile Disk).

[0050] 10 is a diagram showing a processing circuit 93 in a case where some or all of the functions of the contact opening / closing detection unit 5, the trip device 6, and the auxiliary contact output unit 7 of the circuit breaker 2 of the insulation monitoring system 50 according to the first embodiment are realized by the processing circuit 93. In other words, some or all of the functions of the contact opening / closing detection unit 5, the trip device 6, and the auxiliary contact output unit 7 may be realized by the processing circuit 93.

[0051] The processing circuitry 93 is dedicated hardware, and may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof.

[0052] Some of the functions of the contact opening / closing detection unit 5, the trip device 6, and the auxiliary contact output unit 7 may be realized by dedicated hardware separate from the hardware that realizes the remaining functions of the contact opening / closing detection unit 5, the trip device 6, and the auxiliary contact output unit 7.

[0053] Some of the functions of the contact open / close detection unit 5, the trip device 6, and the auxiliary contact output unit 7 may be realized by software or firmware, and the remaining functions may be realized by dedicated hardware. In this way, the functions of the contact open / close detection unit 5, the trip device 6, and the auxiliary contact output unit 7 can be realized by hardware, software, firmware, or a combination of these.

[0054] At least a part of the zero-phase current transformer 8 included in the insulation monitoring system 50 according to the first embodiment may be realized by a processor that executes a program stored in a memory, or may be realized by a processing circuit. The memory is a memory equivalent to the memory 92, the processor is a processor equivalent to the processor 91, and the processing circuit is a processing circuit equivalent to the processing circuit 93.

[0055] At least a part of the leakage current measuring unit 10 and the communication processing unit 11 of the leakage current detection device 9 of the insulation monitoring system 50 according to the first embodiment may be realized by a processor that executes a program stored in a memory, or may be realized by a processing circuit. The memory is a memory equivalent to the memory 92, the processor is a processor equivalent to the processor 91, and the processing circuit is a processing circuit equivalent to the processing circuit 93.

[0056] At least some of the communication processing unit 16, average value calculation unit 17, cumulative value calculation unit 18, determination unit 19, and alarm output unit 21 included in the earth leakage determination device 15 of the insulation monitoring system 50 according to the first embodiment may be realized by a processor that executes a program stored in a memory, or may be realized by a processing circuit. The memory is a memory equivalent to the memory 92, the processor is a processor equivalent to the processor 91, and the processing circuit is a processing circuit equivalent to the processing circuit 93.

[0057] At least some of the contact opening / closing detection unit 5, trip device 6, zero-phase current transformer 8A, leakage current measurement unit 10A, average value calculation unit 17A, cumulative value calculation unit 18A, determination unit 19A, and alarm output unit 21 included in the circuit breaker with insulation monitoring function 2A according to embodiment 2 may be realized by a processor that executes a program stored in a memory, or may be realized by a processing circuit. The memory is a memory equivalent to memory 92, the processor is a processor equivalent to processor 91, and the processing circuit is a processing circuit equivalent to processing circuit 93.

[0058] At least some of the contact opening / closing detection unit 5, trip device 6, zero-phase current transformer 8A, leakage current measurement unit 10A, average value calculation unit 17B, cumulative value calculation unit 18B, determination unit 19B, alarm output unit 21, voltage measurement unit 24, current sensor 25, and current measurement unit 26 included in circuit breaker with insulation monitoring function 2B according to embodiment 3 may be realized by a processor that executes a program stored in memory, or may be realized by a processing circuit. The memory is a memory equivalent to memory 92, the processor is a processor equivalent to processor 91, and the processing circuit is a processing circuit equivalent to processing circuit 93.

[0059] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or different embodiments may be combined with each other, or part of the configuration may be omitted or modified within the scope of the gist of the invention. [Explanation of symbols]

[0060] 1 circuit, 2 circuit breaker, 2A, 2B circuit breaker with insulation monitoring function, 3a power supply side terminal, 3b load side terminal, 4 switching contact, 5 contact switching detection unit, 6 trip device, 7 auxiliary contact output unit, 8, 8A zero-phase current transformer, 9 leakage current detection device, 10, 10A leakage current measurement unit, 11 communication processing unit, 12 load, 13 communication terminal, 14 network, 15 leakage current determination device, 16 communication processing unit, 17, 17A, 17B average value calculation unit, 18, 18A, 18B cumulative value calculation unit, 19, 19A, 19B determination unit, 20 display unit, 21 alarm output unit, 22 internal circuit, 23 voltage detection terminal, 24 voltage measurement unit, 25 current sensor, 26 current measurement unit, 50 insulation monitoring system, 91 processor, 92 memory, 93 processing circuit.

Claims

1. a switching contact provided in the internal circuit; a zero-phase current transformer for detecting a leakage current in the internal electric circuit; a leakage current measuring unit that measures the value of the leakage current of the internal electric circuit based on a detection signal from the zero-phase current transformer; a determination unit that monitors insulation of the internal electric circuit based on the value of the leakage current measured by the leakage current measurement unit when the switching contact is closed; a voltage measurement unit configured to measure voltages of any two of a plurality of electric paths constituting the internal electric path on the load side of the switching contact; a calculation unit that determines that the switching contact is closed when it is determined that the value of the voltage measured by the voltage measurement unit is higher than a predetermined value; A circuit breaker with insulation monitoring function, comprising:

2. The determination unit determines whether a leakage current has occurred based on an average value of the leakage current, which is an average value of the leakage current measured by the leakage current measurement unit per predetermined time period, or based on an accumulated value of the leakage current, which is an accumulation of the leakage current values.

2. The circuit breaker with insulation monitoring function according to claim 1.

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