JP2014066563A - Ac control circuit insulation-monitoring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable grasping of an insulation status of an AC circuit and easy identification of a failure point in the AC circuit where insulation resistance is deteriorated, without interrupting monitoring of ground fault in an AC control circuit, and identification of a failure point even in a neutral point of the AC control circuit, the identification having been difficult by conventional techniques.SOLUTION: A device measures zero-phase currents Io flowing in two-phase bus lines by respectively measuring ground voltages Vx, Vy of the two-phase bus lines; calculates phasic differences between the measured ground voltages Vx, Vy of the respective bus lines and the measured zero-phase currents Io; identifies a bus line with deteriorated ground insulation resistance on the basis of the calculated phasic difference; and displays name information of the identified bus line on an LCD part 16.

Description

  The present invention can be used to identify faults with reduced insulation resistance and ground faults at neutral points for buses and load equipment connected to a transformer for transforming high-voltage AC voltage to low-voltage AC voltage. The present invention relates to an insulation monitoring device for a suitable AC control circuit.

A single-phase transformer is used as the transformer arranged on the utility pole. In Japan, the primary side is 200V (high voltage of 6000V and the secondary side is a single-phase three-wire type, which can supply 100V). An earth leakage breaker is connected to the low-voltage secondary winding of the transformer, and power is supplied to the load facility from the two-phase bus via the earth leakage breaker, which is called a 200 V AC control circuit.
On the other hand, a transformer arranged in a substation generally uses a three-phase transformer.
Conventionally, failures caused by a decrease in the insulation resistance of the AC control circuit can be detected by installing an earth leakage breaker between the low-voltage secondary winding of the transformer and the two-phase bus as described above. Met.
However, when the earth leakage breaker is not installed or when the earth leakage breaker does not operate due to a small decrease in insulation resistance, it is in a situation where it is not possible to determine a decrease in insulation resistance.
In general, factories and company facilities often measure insulation resistance by powering off an AC control circuit during periodic inspection. However, since periodic inspections are only performed once every few years, or load facilities that are difficult to be interrupted may be included, it is difficult to grasp the insulation state with load facilities.
Therefore, there has been a demand for measuring insulation resistance during operation for load facilities that are difficult to be interrupted.

As a technology that meets such a demand, Patent Document 1 discloses a technique for performing insulation failure management using an insulation resistance meter by powering down electric circuits and electrical equipment in response to a request for uninterruptible power generation by an advanced information society. The point which came to use the method of measuring a leakage current by uninterruptible power is disclosed.
Specifically, the two-phase or three-phase ground voltage of the three-phase four-wire system or the three-phase three-wire power distribution system that is fed from a power source in which the low-voltage three-phase winding of the transformer is connected in a star shape Alternatively, measure the two-phase or three-phase line voltage of the three-phase line voltage, and measure the zero-phase current that is the ground leakage current that flows through the distribution line and / or its load equipment fed from the star power supply. Calculate the phase difference between the measured two-phase or three-phase ground voltage or two-phase or three-phase line voltage and the measured zero-phase current, and from the values of the phase difference, voltage, and zero-phase current, A technique is disclosed in which a total value of leakage currents of respective phases flowing through the ground insulation resistance of the distribution line and / or its load equipment is calculated.

JP 2009-145122 A

However, the conventional method has the following problems.
(1) If the fault point where the insulation resistance of the AC control circuit is reduced is a neutral point that is connected to the bus only when the relay or switch is operated, it is extremely difficult to identify the fault point. There is a problem that it is often difficult to identify the accident point even if the insulation resistance is measured after a power failure.
Here, with reference to the circuit diagram shown in FIG. 8, a ground fault at a neutral point in the conventional 200V AC control circuit will be described.
For example, the failure point P1 shown in FIG. 8 is electrically at the same potential as the y bus when the contact a is in the OFF state, and the state connected to the y bus via the relay X changes when the contact a is turned ON. Although not present, the potential is the same as that of the x bus. Further, the failure point P2 is unstable in potential when both the contact b and the contact c are not operating, and is in a situation slightly different from the potential of the x bus and the potential of the y bus.
Further, when only the contact c is operated, the potential is the same as that of the y bus as in the case of the failure point P1, and when only the contact b is operated or both the contacts b and c are operated, the potential is the same as that of the x bus. In addition, a failure point that becomes the potential of either bus depending on the operation state of the contact is called a neutral point.

(2) Even when the earth leakage breaker is activated, it is necessary to measure the insulation resistance to determine the bus at the fault point. In the case of an accident at a neutral point, the fault point cannot be easily identified. There were many problems.
For example, as for the current supplied from the earth leakage breaker, the current supplied from one pole returns to the other pole as long as there is no leakage (leakage) in the electric circuit regardless of whether it is a 2-pole earth leakage breaker or a 3-pole earth leakage breaker. . However, if there is a leakage, the current obtained by subtracting the leaked current from the current supplied from one pole will return, so measure the difference between the current supplied by the zero-phase current transformer and the returned current. Is possible. If this current exceeds a certain value, it is determined that a leakage has occurred, and the leakage breaker automatically shuts off. The operating current of a general earth leakage breaker is set to about 30 mA to 500 mA. For example, in a 200V circuit, it may be within 0.1 seconds at 30 mA, for example (depending on the target circuit).
As an example where the earth leakage breaker does not operate, in addition to the failure of the earth leakage breaker, if the insulation resistance decreases at the failure point on the winding that is in the middle of the potential of the winding equipment (eg motor), this failure point Because the ground potential cannot be detected, it will not operate even if the earth leakage breaker is normal.

(3) At the point P1 shown in FIG. 8, even if a ground fault occurs, the ground fault current flowing in the earth leakage circuit breaker operates with the magnitude of the series resistance of the voltage relay X and the ground fault fault resistance Rg. If the relay X is a voltage relay, the earth leakage breaker may not operate because the internal impedance is high.
In addition, when a ground fault occurs at point P2, if the contact point b or the contact point c does not operate, the earth leakage circuit breaker ELB does not operate and the fault point where the ground fault occurs is often unknown.

  In particular, if the fault point where the insulation resistance of the AC control circuit is reduced is a neutral point that is connected to the bus only when the relay, switch, etc. operate, there will be an accident even if the insulation resistance is measured after power failure. In many cases, it was difficult to identify points. In addition, even when the earth leakage circuit breaker operates, it is necessary to measure the insulation resistance in order to determine the bus at the fault point. However, in the case of an accident at a neutral point that is connected to the bus only when the contact operates, there is a problem that the accident point cannot be easily identified in many cases.

  The present invention has been made in view of the above, and as its purpose, it becomes possible to grasp the insulation state of the AC circuit without interrupting the ground fault monitoring of the AC control circuit, and the insulation resistance in the AC circuit It is an object of the present invention to provide an insulation monitoring device for an AC control circuit that can easily identify a faulty point where the drop has occurred and that can be identified even at a neutral point of an AC control circuit that has been difficult to identify.

  In order to solve the above-mentioned problem, an invention according to claim 1 is an AC control circuit for supplying power to a load facility from a two-phase bus connected to a low-voltage secondary winding of a transformer via a leakage breaker. On the other hand, the two-phase bus is an insulation monitoring device for an AC control circuit that monitors a decrease in ground insulation resistance in the two-phase bus or / and the load facility prior to an earth leakage interrupting operation of the earth leakage breaker, Voltage measuring means for measuring the ground voltage of each, zero-phase current measuring means for measuring the zero-phase current flowing in the two-phase bus, ground voltage of each bus measured by the voltage measuring means, the zero-phase Signal processing means for calculating the phase difference between the zero-phase current measured by the current measuring means, and determination means for specifying the busbar with reduced ground insulation resistance based on the phase difference calculated by the signal processing means And by the determination means A insulation monitoring device of the AC control circuit, characterized in that it comprises a display means for displaying the name information for that bus.

According to the present invention, the leakage breaker of the earth leakage breaker is connected to the AC control circuit that supplies power to the load equipment from the two-phase bus connected to the low-voltage side secondary winding of the transformer via the earth leakage breaker. Prior to operation, the phase difference between the ground voltage and zero-phase current of each bus was calculated when monitoring the decrease in ground insulation resistance in the two-phase bus or / and the load facility. Based on the phase difference, the bus with reduced ground insulation resistance is identified and the name information of the identified bus is displayed, so you can grasp the insulation status of the AC circuit without interrupting the ground fault monitoring of the AC control circuit This makes it possible to easily identify the fault point where the insulation resistance in the AC circuit is reduced.
Further, it is possible to specify the neutral point of the AC control circuit, which has been difficult to specify conventionally.

It is a circuit diagram which shows the insulation monitoring apparatus of the 200V alternating current control circuit which concerns on 1st Embodiment of this invention. It is a flowchart for demonstrating operation | movement of the insulation monitoring apparatus 10 of the 200V alternating current control circuit which concerns on 1st Embodiment of this invention. It is a flowchart of the subroutine which shows the processing content in step S20 shown in FIG. It is a figure for demonstrating the operation example of an alternating current control circuit when the zero phase current Io of an alternating current circuit fluctuates. It is a circuit diagram which shows the structure which makes the three-phase 200V alternating current to which the 200V alternating current control circuit which concerns on 2nd Embodiment of this invention is connected. (A) The primary winding side of a transformer, (b) The secondary winding side of a transformer, (c) It is the figure which carried out vector display of the ground voltage of each phase. 6 is a flowchart of a subroutine showing a phase difference calculation method for the single-phase three-wire AC control circuit shown in FIG. 5. It is a circuit diagram for demonstrating the ground fault accident in the neutral point in the conventional 200V alternating current control circuit.

<First Embodiment>
The insulation monitoring apparatus 10 of the 200V AC control circuit 1 according to the first embodiment of the present invention will be described with reference to the drawings.
A single-phase transformer is used as the transformer arranged on the utility pole. In Japan, the primary side is 200V (high voltage of 6000V and the secondary side is a single-phase three-wire type, which can supply 100V).
For example, a high voltage of 6000 V AC is supplied to the primary side of the transformer Tr shown in FIG. As a winding method of the transformer Tr, a single phase transformer is generally combined with a transformer arranged on a utility pole. On the other hand, a transformer arranged in a substation generally uses a three-phase transformer. In FIG. 1, the transformer arrange | positioned on the common utility pole is represented, and the primary side is represented by 200V (100V is also supplyable) of the high voltage | voltage 6000V and the secondary side is a single phase three-wire system. It is assumed that such a single-phase three-wire system is most frequently used in Japan.
On the secondary side of the transformer Tr, a 200V AC control circuit 1 to be monitored is provided via a circuit breaker MCCB for wiring. Further, another line can be connected to the secondary side of the transformer Tr.
In FIG. 1, it is shown that the x bus-to-ground insulation resistance Rx is connected to the x bus, the y bus-to-ground insulation resistance Ry is virtually connected to the y bus, and the x and y buses are respectively connected to the virtual In other words, it indicates that the ground fault resistance Rg is connected.

As a load facility connected to the x bus and y bus of the 200V AC control circuit 1, a combination of contacts such as a relay and a changeover switch provided in the control circuit and a coil provided in the relay is assumed. Also, depending on the component, a drive circuit using a small motor and an AC / DC converter using a DC component inside the component are also assumed. In addition to these, resistance loads such as lamps and electric heaters (heaters) are assumed. When these loads are operating normally without a ground fault, the current flowing through the x bus and the current flowing through the y bus are the same.
A clamp type zero-phase current transformer ZCT and an insulation monitoring device 10 are provided on the bus side of the circuit breaker MCCB for wiring. The insulation monitoring device 10 inputs a zero-phase current Io detected by a zero-phase current transformer ZCT, a ground voltage Vx of a monitored x bus, and a ground voltage Vy of a y bus, and one end of which is connected to a grounding point. Connect the other end.

In FIG. 1, the zero-phase current transformer ZCT is arranged so as to clamp both the x-bus and the y-bus, and the zero-phase current transformer ZCT detects a leakage current. That is, the zero-phase current transformer ZCT detects the difference between the current flowing through the x bus bar of the circuit breaker MCCB for wiring and the current returning from the y bus bar to the circuit breaker MCCB for wiring.
Accordingly, when there is no leakage, all of the current flowing out to the x bus returns from the y bus, so that the current outflow and inflow subtraction becomes zero and the leakage breaker does not operate.
However, of the current flowing out to the x bus, for example, if 40 mA leaks, the 40 mA current does not return from the y bus, so the output of the zero-phase current transformer ZCT is 40 mA. In this case, when the operating current of the earth leakage breaker is 30 mA, the earth leakage breaker operates. Further, the zero-phase current transformer ZCT measures current, and the voltage is not related regardless of whether the voltage of the x bus and the y bus is 100V, 200V, or 400V.

The insulation monitoring apparatus 10 includes an A / D conversion unit 11, an MPU unit, a storage unit 13, an I / O interface unit, an LED unit 15, an LCD unit 16, and a relay RL1.
The A / D converter 11 inputs the ground voltage Vx of the x bus and the ground voltage Vy of the y bus, and converts an analog voltage signal into digital data with a clock having a predetermined sampling frequency. The A / D converter 11 has a current-voltage conversion circuit, converts the zero-phase current Io detected by the zero-phase current transformer ZCT into a voltage signal, and then converts the analog voltage with a clock having a predetermined sampling frequency. Convert the signal to digital data. In the present embodiment, in order to simplify the description, data after A / D conversion of the zero phase current Io is referred to as a zero phase current Io.

Next, the input range of the A / D conversion unit 11 will be described.
The voltages Vx and Vy are used as a reference for obtaining the phase of the zero-phase current Io. Since the voltages Vx and Vy are AC circuits having an effective value of 100V, the voltages Vx and Vy are 100V × √2 times around 0V. For this reason, it changes in the range of about + 141V--141V. Further, since the 100V voltage is about 110V, which is higher near the secondary side of the transformer Tr, it is sufficient that the voltage is about ± 156V and that ± 200V is allowed.
The A / D conversion unit 11 has a current-voltage conversion circuit for converting an input current into a voltage. Since the operating current of the leakage breaker MCCB that is generally used is 30 mA to 500 mA, the input current range of the A / D converter 11 may be set so that about 500 mA is maximized. For example, if the earth leakage circuit breaker MCCB operates at 30 mA, it operates at 30 mA or more, and it is necessary to grasp a sign of earth leakage before reaching the current value. If the A / D converter 11 is 10 bits, a resolution of 1 mA can be sufficiently obtained. Since the input of the A / D converter 11 is not a voltage but a current, if expressed in terms of a current value, there is no problem in most cases with 0 to 500 mA.

The MPU unit 12 includes an MPU, a RAM, and a timer. The MPU reads a control program stored in the storage unit 13 on the RAM and controls the insulation monitoring apparatus 10 as a whole.
The storage unit 13 stores a control program and stores control data and a previous measurement value as a work area with an occurrence time added. The storage unit 13 records the insulation resistance value as a history.
The I / O interface unit displays information on the LED unit 15 and the LCD unit 16 according to display information from the MPU unit 12 and closes the contact of the relay RL1 according to alarm information from the MPU unit 12.
The LED unit 15 has, for example, green, yellow, and red LEDs as a plurality of different light emission colors, and displays the warning levels in different colors according to display information from the MPU unit 12. The LCD unit 16 displays the bus name, effective current value, neutral point, and the like with reduced insulation in text according to display information from the MPU unit 12. Relay RL1 closes the contact according to alarm information from MPU unit 12, and informs the outside that the insulation resistance has decreased. For example, any one of a buzzer, a siren, a warning light, and the like may be connected in series to the relay RL1.

Next, functions of the insulation monitoring device 10 will be described.
(1) When the zero-phase current Io is constantly monitored and becomes a certain value (eg, 1 mA) or more, the phase in which the insulation resistance decreases from the phase of the zero-phase current Io and the voltage to ground (Vx and Vy) A function of determining and displaying (x bus bar, y bus bar) and outputting an alarm sound.
(2) When the phase of the zero-phase current Io is compared with the previous measured value Io ′ and reversed, the failure point (neutral point) where the insulation resistance is lowered is determined, displayed, and an alarm sound is output. function.
(3) A function for recording and displaying values before and after the change (Io, Vx, Vy) and occurrence time when the phase of the zero-phase current Io is inverted.
(4) The zero-phase current Io is constantly measured, and when there is a change of a predetermined value or more (for example, a change of ± 0.5 mA or more) as compared with the previous value, values before and after the change (Io, Vx, Vy) and the function of recording and displaying the time of occurrence.
(5) A function of automatically measuring the zero-phase currents Io, Vx, and Vy periodically and recording and displaying the measurement time, measurement value, and the like.
(6) A function for recording the AC circuit insulation resistance value as a history with a configuration in which the measurement interval of the apparatus can be arbitrarily set (for example, every hour or every day).
(7) A function to display each numerical value and the failed point using a liquid crystal screen or lamp for easy understanding.

Next, the operation of the insulation monitoring apparatus 10 of the 200V AC control circuit according to the first embodiment of the present invention will be described with reference to the flowchart shown in FIG.
The MPU unit 12 reads out a control program stored in the storage unit 13 on the RAM when starting up, and starts control of the insulation monitoring device 10.
First, in step S10, the MPU unit 12 measures the ground voltage and zero phase current of each phase. That is, since the A / D converter 11 is supplied with the ground voltage Vx of the x bus, the ground voltage Vy of the y bus, and the zero-phase current Io, Vx, Vy, Io are generated by a clock having a predetermined sampling frequency. And the current measurement value is stored in the storage unit 13. Here, the ground-to-ground voltages Vx and Vy and the zero-phase current Io of each bus line are averaged by performing continuous measurement several times (for example, five times) in order to eliminate the influence due to the transient phenomenon that occurs when the load is stopped. This prevents malfunction due to erroneous input.
Specifically, the AC circuit load has a capacitance between the ground and the charge is not accumulated when a voltage is applied (operation start), and a charging current flows through the capacitance together with a transient current at the start of operation. Since these currents stabilize in a few seconds, for example, the influence of the transient current can be mitigated by measuring five times at intervals of 3 seconds and averaging. If this is a single measurement, if the measured time overlaps with the start of load operation, there is a possibility of erroneous determination based on the transient current. However, since the sensitivity when detecting a decrease in insulation resistance at the neutral point decreases, only when a decrease in insulation resistance at the neutral point is detected, the measurement interval is, for example, 5 times at 0.5 second intervals. You may control to measure and average.

Next, in step S15, the MPU unit 12 determines whether the zero-phase current Io is equal to or greater than a predetermined value 1 (eg, 1 mA) as the condition 1.
The predetermined value 1 is a value for determining whether the apparatus flows in the flow for determining the insulation state or whether there is no problem in the insulation state and it is not necessary to flow in the determination flow. Further, the display condition is only when the insulation state is surely lowered when the polarity of the zero-phase current Io is reversed in a short time. For this reason, if the insulation state deteriorates, the zero-phase current Io flows, and when the sensitivity is increased, the predetermined value 1 may be set to a smaller current value. When the operating current value of the earth leakage breaker MCCB is about 100 mA and a relatively large value, it is not necessary to frequently perform the determination flow process. On the other hand, for example, in the earth leakage circuit breaker MCCB operating at 30 mA, in the case of three-stage display, it may be about 1 to 5 mA.
If it is determined in step S15 that the zero-phase current Io is not equal to or greater than a certain value (eg, 1 mA) (No in S15), the process proceeds to step S50. On the other hand, if the zero-phase current Io exceeds a certain value (eg, 1 mA) (Yes in S15), the process proceeds to step S20, and the insulation resistance decreases from the phase of the zero-phase current Io and the ground voltages Vx and Vy. Phase (x bus, y bus) is determined.

The processing content in step S20 will be described in detail in the subroutine shown in FIG.
Here, a process of calculating the phase difference Δθ between the voltages Vx and Vy and the zero-phase current Io will be described with reference to the subroutine shown in FIG. FIG. 3 is a flowchart showing a phase difference Δθ calculation method when the AC control circuit is the single-phase three-wire system shown in FIG. In this embodiment, the zero cross method is employed as an example of an algorithm for obtaining the current phase.
In order to execute the processing in the subroutine shown in FIG. 3, the MPU unit 12 outputs a clock having a predetermined sampling frequency to the A / D conversion unit 11, samples Vx, Vy, and Io, and stores each data. Assume that you are entering.

First, in step S105, the MPU unit 12 determines whether or not the polarity of the voltage Vx has changed from negative to positive, and if there is such a change (Yes in S105), the MPU unit 12 proceeds to step S110, The time is read and stored in the storage unit 13 as time 1 when the polarity of the voltage Vx changes from minus to plus.
Next, in step S115, the MPU unit 12 determines whether the polarity of the zero-phase current Io changes from minus to plus after time 1, and when there is such a change (Yes in S115), the MPU unit 12 proceeds to step S120. The current time is read from the timer and stored in the storage unit 13 as time 2 when the polarity of the zero-phase current Io changes from minus to plus.
Next, in step S125, the MPU unit 12 obtains the phase difference Δθ by reading the times 1 and 2 from the storage unit 13 and subtracting the time 1 from the time 2 to obtain the time difference ΔT.
Phase difference Δθ = 60 × (time 2−time 1) second × 360 degrees In other words, when the power supply frequency is 60 Hz, one cycle is 1/60 second, so if one cycle is 16.67 ms,
The phase difference Δθ≈time difference ΔT ÷ 16.67 × 360 degrees.
For example, if the time difference ΔT is 12.5 ms, the phase difference Δθ = 12.5 / 16.67 × 360≈270 degrees, and the zero-phase current Io is delayed by 270 degrees. That is, it advances 90 degrees.

Here, in step S130, the MPU unit 12 determines whether or not the phase difference Δθ obtained by the above calculation method is in the range of 270 to 360 degrees. When the phase difference Δθ is in the range of 270 to 360 degrees (Yes in S130), the process proceeds to step S135.
In step S135, the MPU unit 12 causes the zero-phase current Io to range from 0 degrees to 90 degrees with respect to the voltage Vx.
Phase = phase difference Δθ-360
Is calculated, and this subroutine is terminated to return to the main routine.
Minus indicates progress. Conversely, if the phase difference Δθ is in the range of 90 to 180 degrees, the advance range is 90 degrees to 0 degrees with respect to the voltage Vy. That is, in the case of the single-phase three-wire system, the voltage Vy has a phase of 180 degrees with respect to the voltage Vx. Therefore, it is possible to obtain only the phase of the zero-phase current Io with respect to the voltage Vx without having information on the voltage Vy. The phase difference Δθ with respect to the voltage Vy can be obtained.
However, when any two phases of the three-phase AC circuit are used, the zero-phase current Io is in the range of 0 to 90 degrees with respect to the voltage Vx or the range of 0 to 90 degrees with respect to the voltage Vy. It is necessary to ask if there is. This is because it is not known which part of the three-phase AC circuit is grounded.

On the other hand, if it is determined in step S130 that the phase difference Δθ is outside the range of 270 to 360 degrees (No in S130), the process proceeds to step S140.
In step S140, the MPU unit 12 determines whether or not the phase difference Δθ obtained by the above calculation method is in the range of 90 to 180 degrees. When the phase difference Δθ is in the range of 90 to 180 degrees (Yes in S140), the process proceeds to step S145.
In step S145, the MPU unit 12 causes the zero-phase current Io to range from 0 degrees to 90 degrees with respect to the voltage Vy.
Phase = phase difference Δθ−180
Is calculated, and this subroutine is terminated to return to the main routine.
On the other hand, if it is determined in step S140 that the phase difference Δθ is outside the range of 90 to 180 degrees (No in S140), the process proceeds to step S150, and the phase difference Δθ is outside the specified range, and this subroutine is terminated. And return to the main routine.

In step S20, when the insulation resistance of the x bus is lowered, a leakage current flows to the failure point where the insulation resistance is lowered by the voltage Vx applied between the x bus and the ground. In general, there is a capacitance other than the insulation resistance between the circuit and the ground. The current flowing through the capacitance is not due to the decrease in the insulation resistance, and the current is 90 degrees with respect to the voltage. It becomes a component to advance. For this reason, it can be determined that the insulation resistance has decreased by detecting the current in the same phase of the zero-phase current Io with respect to the voltage Vx between the x bus and the ground. For this reason, if the voltage Vx and the zero-phase current Io are currents ranging from 0 degrees to 90 degrees, it can be understood as a decrease in the insulation resistance of the x bus. Further, since the voltage Vx and the voltage Vy have a phase difference Δθ of 180 degrees, if the processing is performed only when the voltage Vx and the voltage Vy are in the range of 0 degrees to 90 degrees, it is not erroneously determined that the insulation resistance of the y bus has decreased. . Similarly, the voltage Vx changes to the voltage Vy for the insulation resistance of the y bus.
In step S20, when the phase between the voltage Vx and the zero-phase current Io is 0 to advance and is within 90 degrees, it is determined that the x bus has failed. On the other hand, the phase between the voltage Vy and the zero-phase current Io is 0 to advance. If it is within 90 degrees, it is determined that the y bus has failed, and the process proceeds to step S45. In the case of the single-phase three-wire system, the phases of the voltage Vx and the voltage Vy are opposite in a normal state.

Next, in step S25, the MPU unit 12 reads the previous measurement value Io ′ from the storage unit 13, and as condition 2, whether or not the difference value obtained by subtracting the previous measurement value Io ′ from the zero-phase current Io is equal to or greater than a predetermined value 2. Judging. Note that the predetermined value 2 is a threshold when the change in the leakage current Io changes slowly, and it is necessary to increase the sensitivity, and is preferably about ± 0.5 mA or ± 1 mA.
In step S25, when the predetermined value is not 2 or more (No in S25), the process proceeds to step S50. On the other hand, if the value obtained by subtracting the previous measured value Io ′ from the zero-phase current Io is equal to or larger than the predetermined value 2 (Yes in S25), the process proceeds to step S30, and it is determined that the insulation resistance is decreasing. Proceed to S45.

Next, in step S35, the MPU unit 12 reads the previous measured value Io ′ from the storage unit 13, and as the condition 3, the phase of the zero-phase current Io and the previous measured value Io ′ is reversed, or the zero-phase current up to the previous time If the polarity of the current zero-phase current value Io has not been restored (the polarity has been restored in a short time) after the polarity of the value Io ′ has temporarily changed to a different polarity (No in S35), the process proceeds to step S50. On the other hand, after the phase of the zero-phase current Io and the previous measured value Io ′ is reversed or the polarity of the previous zero-phase current value Io ′ is temporarily changed to a different polarity, the polarity of the current zero-phase current value Io is When it returns (returns in a short time) (Yes in S35), the process proceeds to step S40, and it is determined that the ground fault point (the failure point where the insulation resistance has decreased) is a neutral point, and the process proceeds to step S45.
Here, in step S35, the voltages Vx, Vy, and the zero-phase current Io are measured at a certain time interval (for example, every 10 seconds). For example, the phase of the previously measured zero-phase current Io ′ is 75 degrees with respect to Vy. In this case, if the phase of the zero-phase current Io is 255 degrees with respect to the voltage Vy and the value changes to 1 mA in the next measurement, the polarity of the zero-phase current Io is reversed (75 degrees +180 degrees). = 255 degrees). This corresponds to the case where the contact a operates in a state where the insulation resistance is lowered at the failure point P1 shown in FIG. Before the contact a is operated, the voltage applied to the failure point where the insulation resistance is lowered is Vy. When the contact a is operated, the voltage is changed to Vx, and the voltage phase of the voltage Vx and the voltage Vy is inverted by 180 degrees. Therefore, it can be understood that the current also reverses.

Next, in step S45, the MPU unit 12 outputs a warning instruction to the I / O interface unit 14 because there is a failure point whose insulation resistance has decreased as a result of the determination in steps S20, S30, and S40. As a result, the I / O interface unit 14 closes the contact of the relay RL1, and operates the buzzer connected to the contact of the relay to generate an alarm sound. As a result, an alarm is generated when the ground insulation resistance is reduced, so that it is possible to easily identify the load facility that was activated when the alarm occurred.
In step S45, the MPU unit 12 performs the following lighting control on the LED unit 15.
If the operating current of the earth leakage breaker MCCB is 30 mA, the circuit will be out of power when a current of 30 mA flows. Therefore, it is only necessary to detect and display the precursor reaching 30 mA in stages.
For example, the state in which the insulation resistance deteriorates is divided into three stages, for example, the effective component of the zero phase current Io is 10 mA or less, the normal range is 10 to 20 mA, the caution range is 20 mA to 30 mA, and the zero phase current Io is When the LED is within the normal range, the green LED element of the LED unit 15 is lit, the yellow LED element is lit when it is in the caution range, and the red LED element is lit when it is in the caution range. Also good.
Thereby, the state where insulation resistance deteriorated according to the luminescent color of the LED element in lighting can be visually confirmed.

In addition, the labels “X bus”, “Y bus”, and “neutral point” indicating the failure point with reduced insulation resistance are attached below each LED, and the LED element corresponding to the failure point is lit. May be.
Thereby, it is possible to visually confirm the failure point where the insulation resistance is lowered from the label corresponding to the LED element being lit.
In step S45, the MPU unit 12 performs the following display control on the LCD unit 16.

Simultaneously with the display on the LED unit 15, the bus name and effective current value whose insulation resistance has been reduced are displayed on the LCD unit 16. In addition, when the polarity of the zero-phase current Io is reversed, or when the polarity changes in a short time and returns, it is determined that the neutral point is low in insulation. May be displayed.
For example, as an example of display on the LCD unit 16, display is performed in the order of [time, measurement value, failure point]. The MPU unit 12 reads out the time, measured value, and failure point from the storage unit 13 and displays them. The time is displayed in the order of hour, minute, second, the measured value is the zero-phase current Io in unit of mA, and any one of x bus, y bus, and neutral point is displayed as the failure point. Thereby, it can confirm that the fall of ground insulation resistance is in progress, generation | occurrence | production time, a zero-phase electric current value, a bus name, or a neutral point.
Further, for example, when it is determined whether or not the phase of the current zero-phase current value is inverted so as to be the phase of the previous zero-phase current value stored in the storage unit 13, and the phase is inverted Confirms that the decrease in ground insulation resistance is in progress at the neutral point by displaying “Neutral Point” as the name information indicating that the failure point where the ground insulation resistance has decreased is the neutral point. can do.

By displaying the past history upward and the latest history downward according to the number of lines displayed on the LCD unit 16, it is possible to display the history of time, measured values, and failure points in time series. it can.
The zero-phase current Io is constantly measured, and the difference value obtained by subtracting the previous zero-phase current Io read from the storage unit 13 from the current zero-phase current Io is compared with a predetermined value, and the difference value changes more than the predetermined value ( For example, when there is a change of ± 0.5 mA or more, the values before and after the change (Io, Vx, Vy) and the time of occurrence are recorded and displayed on the LCD unit. In this case, the text “in progress” is displayed as information indicating that a decrease in ground insulation resistance is in progress. As a result, it is possible to confirm that the ground insulation resistance is decreasing, the generation time, the zero-phase current value, and the bus voltage.
In addition, when the accident point where the ground insulation resistance is reduced is a neutral point, the occurrence time is also displayed on the LCD unit 16, so that an auxiliary means for searching for a load facility that has been operated at the corresponding time from among a plurality of load facilities. Can be used.

Next, in step S50, the MPU unit 12 determines whether or not the time read from the timer is the measurement time. If the measurement time is reached (Yes in S50), the process proceeds to step S55. If the measurement time is not reached (No in S50), the process proceeds to step S10.
Next, in step S55, the MPU unit 12 records the measurement value in step S10 and the time data read from the timer in the storage unit 13 (including a fault point recording in the case of failure).

Next, an example of the operation of the AC control circuit when the zero-phase current Io of the AC circuit varies will be described with reference to FIG. FIG. 4 is an explanatory diagram showing that the zero-phase current has fluctuated.
An example in which a small ground fault of 100 kΩ has occurred at point P1 of the AC control circuit shown in FIG. In addition, the insulation resistance of the AC circuit is 1 MΩ for both the x bus-to-ground insulation resistance Rx and the y bus-to-ground insulation resistance Ry, and the relay resistance is 44 kΩ (an example where the operating current is 5 mA with a 200 V voltage relay).
First, when the contact a is not operating, a closed circuit of the path K1 is always formed, which is the neutral point of the transformer Tr → the ground fault resistance Rg → the voltage relay X → the circuit breaker MCCB → the transformer Tr. 110V is applied to the combined resistance 144 kΩ of the resistance of the fault and the relay resistance.
For this reason, a current of about +0.76 mA flows through the path K1. If the direction of the current flowing into the insulation monitoring device 10 is assumed to be positive, if the MCCB is an earth leakage breaker (ELB) and the operating current is 1 mA, the ELB will not operate even if the control circuit has a reduced insulation. .

Next, when the contact a is operated, when the contact a is operated, a closed circuit of the path K2 is configured from the transformer Tr to the circuit breaker MCCB → the contact a → the ground fault resistance Rg → the neutral point of the transformer Tr. 110V is applied to the resistance 100 kΩ, and a current of 1.1 mA flows in the direction of the path K2. Further, the operating current flows through the relay X at 5 mA (220 V / 44 kΩ = 5 mA), the voltage across the relay X becomes 220 V, the voltage across the grounding resistance Rg becomes 110 V, and the current flowing through the grounding resistance Rg is in the red direction. -1.1 mA only. That is, in the closed circuit of the path K1, the transformer voltage 110V + the ground fault resistance voltage 110V becomes the relay voltage 220V, and the current in the K1 direction does not flow.
Therefore, the current flowing through the insulation monitoring device is reversed from +0.76 mA before the operation of the contact a to -1.1 mA, and when the earth leakage breaker is used, the operation of the contact a At the same time, the accident is interrupted and the control circuit is interrupted. In addition, when the circuit breaker MCCB for wiring is used, it will not be determined as a failure even if a breakdown of a decrease in insulation resistance occurs without causing an accidental interruption, and the operation is continued.
In addition, although the current due to the ground capacitance flows in the AC circuit, if the x bus and the y bus have the same capacity, they cancel each other, and if the insulation resistance is 1 MΩ or more, there will be no large error. The operation was briefly described without considering these.

  Insulation monitoring device of AC control circuit has a function that can record alarm output and data before and after change with time when zero phase current Io exceeds a predetermined value or when the polarity of zero phase current is reversed. By comparing the data with the operation records of the electric station equipment, it is possible to sufficiently grasp the precursors before proceeding to the AC circuit ground fault (accident interruption). If there is a need to allow the malfunction of the device to grasp the state at an early stage, the operation setting value (predetermined value) of the device is set to a smaller value (for example, ± 0.2 mA). The status can be grasped.

As described above, the leakage breaker operation of the earth leakage breaker for the AC control circuit that supplies power to the load equipment from the two-phase bus connected to the low-voltage side secondary winding of the transformer via the earth leakage breaker Prior to monitoring the decrease in ground insulation resistance in the two-phase bus or / and the load equipment, the phase difference Δθ between the ground voltage and zero-phase current of each bus was calculated and calculated. Based on the phase difference Δθ, the bus with reduced ground insulation resistance is identified and the name information of the identified bus is displayed, so you can grasp the insulation status of the AC circuit without interrupting the ground fault monitoring of the AC control circuit This makes it possible to easily identify the fault point where the insulation resistance in the AC circuit is reduced.
Further, it is possible to specify the neutral point of the AC control circuit, which has been difficult to specify conventionally.

Second Embodiment
An insulation monitoring device 10 of a 200V AC control circuit 1 according to a second embodiment of the present invention will be described with reference to the drawings.
First, with reference to FIG. 5, the structure which produces the three-phase 200V alternating current to which the 200V alternating current control circuit which concerns on 2nd Embodiment of this invention is connected is demonstrated.
FIG. 5 shows a case where 200 V is supplied to a general consumer, and a single-phase three-wire transformer (in FIG. 5, a transformer Tr1 on the pole) is replaced with another single-phase transformer (FIG. 5). Then, it is a circuit diagram which shows making the alternating current of three-phase 200V by V-connecting the transformer Tr2) on a pillar.
FIG. 6 is a vector representation of (a) the primary winding side of the transformer, (b) the secondary winding side of the transformer, and (c) the ground voltage of each phase.

In this case, as a 200V AC control circuit, when using a red / white phase, it is the same as using a single-phase three-wire type 200V. And the phase will be different.
(1) In the case of a white blue phase, the ground voltage of the white phase is 100 V, the ground voltage of the blue phase is 173 V, and the phase of the blue phase voltage is 90 degrees behind the white phase (see FIG. 6C).
(2) In the case of the blue-red phase, the ground voltage of the blue phase is 173 V, the ground voltage of the red phase is 100 V, and the phase of the blue phase voltage is 90 degrees ahead of the red phase (see FIG. 6C).

In the second embodiment, with respect to the AC control circuit shown in FIG. 5, the red phase is the x bus and the white phase is the y bus, and the zero-phase current transformer ZCT is clamped to both the x bus and the y bus. The zero-phase current transformer ZCT detects a leakage current. The insulation monitoring device 10 inputs a zero-phase current Io detected by a zero-phase current transformer ZCT, a ground voltage Vx of a monitored x bus, and a ground voltage Vy of a y bus, and one end of which is connected to a grounding point. Connect the other end.
The internal configuration of the insulation monitoring apparatus 10 is the same as the configuration shown in FIG.
Since the operation of the insulation monitoring apparatus 10 of the 200V AC control circuit according to the second embodiment of the present invention is the same as the flowchart shown in FIG. 2 referred to in the first embodiment, the description thereof is omitted.

  The phase determination flow when using the white / blue phase described above and when using the blue / red phase is as follows. In the case of the single-phase three-wire system, since the voltage Vx and the voltage Vy are fixed at a phase difference Δθ of 180 degrees, if the phase of Vx and the zero-phase current Io is known, the phase difference Δθ of Vy and the zero-phase current Io can also be known. However, in the case of three phases, the phase difference between Vx and Vy is not necessarily limited to the phase difference Δθ of 180 degrees, and therefore the phase of the zero-phase current Io with respect to Vx is individually obtained to obtain a predetermined phase difference Δθ (0 to 90 degrees advance). ), The phase difference Δθ between Vy and the zero-phase current Io is obtained again.

Here, a process for calculating the phase difference Δθ between the voltages Vx and Vy and the zero-phase current Io will be described with reference to a subroutine shown in FIG. FIG. 7 is a flowchart of a subroutine showing a phase difference calculation method of the single-phase three-wire AC control circuit shown in FIG. In this embodiment, the zero cross method is employed as an example of an algorithm for obtaining the current phase.
In order to execute the processing in the subroutine shown in FIG. 7, the MPU unit 12 outputs a clock having a predetermined sampling frequency to the A / D conversion unit 11, samples Vx, Vy, and Io, and stores each data. Assume that you are entering.

First, in step S205, the MPU unit 12 determines whether or not the polarity of the voltage Vx has changed from minus to plus, and if there is such a change (Yes in S205), the MPU unit 12 proceeds to step S210, The time is read and stored in the storage unit 13 as time 1 when the polarity of the voltage Vx changes from minus to plus.
Next, in step S215, the MPU unit 12 determines whether the polarity of the zero-phase current Io changes from minus to plus after time 1, and when there is such a change (Yes in S215), the MPU unit 12 proceeds to step S220. The current time is read from the timer and stored in the storage unit 13 as time 2 when the polarity of the zero-phase current Io changes from minus to plus.
Next, in step S225, the MPU unit 12 reads the times 1 and 2 from the storage unit 13, and obtains the time difference ΔT obtained by subtracting the time 1 from the time 2, thereby obtaining the phase difference Δθ.
That is, when the power supply frequency is 60 Hz, one cycle is 1/60 second, so if one cycle is 16.67 ms,
The phase difference Δθ≈time difference ΔT ÷ 16.67 × 360 degrees.
For example, if the time difference ΔT is 12.5 ms, the phase difference Δθ = 12.5 / 16.67 × 360≈270 degrees, and the zero-phase current Io is delayed by 270 degrees. That is, it advances 90 degrees.

Here, in step S230, the MPU unit 12 determines whether or not the phase difference Δθ obtained by the above calculation method is in the range of 270 to 360 degrees. If the phase difference Δθ is in the range of 270 to 360 degrees (Yes in S230), the process proceeds to step S235.
In step S235, the MPU unit 12 causes the zero-phase current Io to be in the range of 0 degrees to 90 degrees with respect to the voltage Vx.
Phase = phase difference Δθ-360
Is calculated, and this subroutine is terminated to return to the main routine.
Minus indicates progress. Conversely, if the phase difference Δθ is in the range of 90 to 180 degrees, the advance range is 90 degrees to 0 degrees with respect to the voltage Vy. That is, if the single-phase three-wire system is used, the voltage Vy has a phase of 180 degrees with respect to the voltage Vx. The phase difference Δθ with respect to Vy can be obtained.
However, when any two phases of the three-phase AC circuit are used, the zero-phase current Io is in the range of 0 to 90 degrees with respect to the voltage Vx or the range of 0 to 90 degrees with respect to the voltage Vy. It is necessary to ask if there is. This is because it is not clear which part of the three-phase AC circuit is grounded.

On the other hand, if it is determined in step S230 that the phase difference Δθ is outside the range of 270 to 360 degrees (No in S230), the process proceeds to step S240.
In step S240, the MPU unit 12 determines whether or not the polarity of the voltage Vy has changed from minus to plus, and if there is such a change (Yes in S240), the MPU unit 12 proceeds to step S245 and sets the current time from the timer. Reading is stored in the storage unit 13 as time 1 when the polarity of the voltage Vy changes from minus to plus.
Next, in step S250, the MPU unit 12 determines whether or not the polarity of the zero-phase current Io changes from minus to plus after time 1, and when there is such a change (Yes in S250), the process proceeds to step S255. The current time is read from the timer and stored in the storage unit 13 as time 2 when the polarity of the zero-phase current Io changes from minus to plus.
Next, in step S260, the MPU unit 12 obtains the phase difference Δθ by reading the times 1 and 2 from the storage unit 13 and obtaining the time difference ΔT obtained by subtracting the time 1 from the time 2.
In step S265, the MPU unit 12 determines whether or not the phase difference Δθ obtained by the above calculation method is in the range of 270 to 360 degrees. When the phase difference Δθ is in the range of 270 to 360 degrees (Yes in S265), the process proceeds to step S270.
In step S270, the MPU unit 12 causes the zero-phase current Io to range from 0 degrees to 90 degrees with respect to the voltage Vy.
Phase = phase difference Δθ-360
Is calculated, and this subroutine is terminated to return to the main routine.

  On the other hand, if it is determined in step S265 that the phase difference Δθ is outside the range of 270 to 360 degrees (No in S265), the process proceeds to step S275, where the phase difference Δθ is outside the specified range, and this subroutine is terminated. And return to the main routine.

As described above, the leakage breaker operation of the earth leakage breaker for the AC control circuit that supplies power to the load equipment from the two-phase bus connected to the low-voltage side secondary winding of the transformer via the earth leakage breaker Prior to monitoring the decrease in ground insulation resistance in the two-phase bus or / and the load equipment, the phase difference between the ground voltage and zero-phase current of each bus is calculated, and the calculated level is calculated. Based on the phase difference, the bus with reduced ground insulation resistance is identified and the name information of the identified bus is displayed, so you can grasp the insulation status of the AC circuit without interrupting the ground fault monitoring of the AC control circuit Therefore, it is possible to easily identify the failure point where the insulation resistance is reduced in the AC circuit.
Further, it is possible to specify the neutral point of the AC control circuit, which has been difficult to specify conventionally.

According to the first and second embodiments, the following effects can be obtained.
(1) It is possible to grasp the insulation status of the AC circuit without interrupting the ground fault monitoring of the AC control circuit, and it becomes easy to identify the fault point where the insulation resistance of the AC control circuit has decreased (equipment reliability Does not decrease the degree).
(2) Since it is possible to continuously grasp the insulation status of the AC circuit, it is possible to identify the failure point where the insulation has decreased by checking the weather conditions (humidity, temperature, weather, etc.) and the insulation state (zero-phase current). This makes it possible to prevent an AC circuit ground fault.

Since moisture in the air has a large effect on insulation degradation, the ambient humidity will be described together with the measurement of the zero-phase current. When the insulation is new, the insulation state hardly deteriorates (zero phase current increases) even when the humidity becomes high, and the insulation becomes more susceptible to moisture as the surface deteriorates or the surface changes. The expression of the relationship between humidity and zero-phase current cannot be expressed uniformly by the scale of the equipment or the installation environment. However, if the humidity and the zero-phase current are displayed in one graph, it can be determined whether or not the insulation state has started to deteriorate. It is also effective to compare with a record several years ago as a criterion. In this method, a person makes a judgment by looking at a record. In addition, the temperature of the insulator may be condensed if there is a rapid rise in temperature.
(3) The neutral point of the AC control circuit, where it was difficult to identify the fault point where the ground fault occurred in the past (the fault where the insulation point is lowered due to contact etc. is connected to the x bus or the y bus) It is possible to specify the point of failure where a ground fault has occurred at a point or a part connected to the charging bus only when the contact is operated.
(4) It becomes possible to identify the fault point where the AC ground fault occurred at an early stage before the operation of the earth leakage circuit breaker (ELB, etc.) and grasp the insulation deterioration of the AC circuit. Transition) can be prevented in advance.

The conventional earth leakage breaker is configured to operate when a zero-phase current exceeding a certain value (for example, 30 mA or more) flows, causing the circuit to fail. However, if it does not reach even 30 mA, it does not operate and is insulated. It was difficult to grasp the situation. On the other hand, according to the insulation monitoring device of the present embodiment, it is possible to grasp the insulation state that gradually deteriorates, and when the insulation state suddenly deteriorates, it is possible to determine a trouble due to intrusion of rainwater or the like. Since the progress of the deterioration state can be known before the insulation state suddenly deteriorates, it is possible to judge an opportunity for equipment inspection before a fatal power failure or equipment damage occurs.
(5) The apparatus can be installed without modifying or changing the existing electrical equipment, and the reliability of the load equipment can be improved.
(6) By adjusting the interval of measuring the insulation state of the AC circuit (for example, once a day), it becomes possible to narrow down the search for the ground fault point when a ground fault occurs from the change in the insulation resistance throughout the year.

  DESCRIPTION OF SYMBOLS 1 ... AC control circuit, 10 ... Insulation monitoring apparatus, 11 ... A / D conversion part, 12 ... MPU part, 13 ... Memory | storage part, 14 ... I / O interface part, 15 ... LED part, 16 ... LCD part, RL1 ... Relay, Tr ... Transformer, Tr1 ... Transformer, Tr2 ... Transformer, ZCT ... Zero-phase current transformer

Claims (8)

Prior to the earth leakage breaking operation of the earth leakage breaker, the AC control circuit supplies power to the load facility from the two-phase bus connected to the transformer low-voltage secondary winding via the earth leakage breaker. An insulation monitoring device for an AC control circuit for monitoring a decrease in ground insulation resistance in a phase bus or / and the load equipment,
Voltage measuring means for measuring the ground voltage of each of the two-phase buses;
Zero-phase current measuring means for measuring a zero-phase current flowing in the two-phase bus;
Signal processing means for calculating a phase difference between the ground voltage of each bus measured by the voltage measuring means and the zero phase current measured by the zero phase current measuring means;
Determination means for identifying a bus having a reduced ground insulation resistance based on the phase difference calculated by the signal processing means;
An insulation monitoring device for an AC control circuit, comprising: display means for displaying name information of a bus specified by the determination means. Comparing means for comparing a difference value obtained by subtracting the previous zero-phase current value from the current zero-phase current value measured by the zero-phase current measuring means with a predetermined value;
The display means displays information indicating that a decrease in the ground insulation resistance is in progress when the difference value is larger than the predetermined value by the comparison by the comparison means. Item 2. The insulation monitoring device for an AC control circuit according to Item 1.   When the difference value changes more than the predetermined value as a result of comparison by the comparison means, the display means displays the zero-phase current value before and after the change and the ground voltage of the bus. The insulation monitoring device for an AC control circuit according to claim 2. Judgment means for judging whether or not the polarity of the current zero-phase current value has been restored after the polarity of the zero-phase current value measured by the zero-phase current measuring means has changed to a different polarity temporarily,
When the polarity of the current zero-phase current value is restored after the polarity of the previous zero-phase current value is changed to a different polarity by the determination means, the display means is a fault that the ground insulation resistance has decreased. 2. The insulation monitoring device for an AC control circuit according to claim 1, wherein name information indicating that the point is a neutral point is displayed. A judgment means for judging whether or not the phase of the current zero phase current value measured by the zero phase current measurement means is reversed so as to be the phase of the previous zero phase current value;
2. The display device according to claim 1, wherein when the phase is reversed by the determination unit, the display unit displays name information indicating that the failure point where the ground insulation resistance is reduced is a neutral point. Insulation monitoring device for AC control circuit. Timer means for measuring the current time,
6. The AC control circuit according to claim 1, wherein, when the ground insulation resistance is reduced, the display unit displays a generation time when the ground insulation resistance is reduced. Insulation monitoring device. A plurality of LED elements having different emission colors;
Range determination means for determining which range of the plurality of predetermined ranges the zero-phase current value measured by the zero-phase current measurement means is,
2. The insulation monitoring device for an AC control circuit according to claim 1, wherein any one of the plurality of LED elements is caused to emit light in accordance with a range determined by the range determining means.   6. The insulation monitoring device for an AC control circuit according to claim 1, further comprising alarm generation means for generating an alarm when the ground insulation resistance decreases.

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