Malfunction detection device and liquid supply device

Abstract

To detect a fact that which one of a power supply side and a load side causes fault.SOLUTION: A fault detection device according to an embodiment of the present invention, comprises: a voltage detection part; a current detection part; and a fault detection part. The voltage detection part detects a three-phase line-to-line voltage waveform on the basis of a three-phase AC voltage input into a power conversion device that supplies a power to a load device as a motor for driving a liquid supply device. The current detection part detects at least a two-phase current waveform from the three-phase AC current output from the power conversion device. The fault detection device separately detects a fact that which one of fault of a power supply side and fault of a load side on the power supply side instead of the power conversion device by analyzing the output of the voltage detection part and the output of the current detection part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fault detection device. reference and liquid supply devices. [Background technology]

[0002] With regard to a liquid supply system, such as a pump device, there is known a technique for detecting a missing phase by detecting the effective current value, maximum current value, and zero-cross current value of the other phase from the current waveforms of two of the three phases between a three-phase AC power source and a three-phase load, and comparing these detected values.

[0003] Another known technology uses current sensors to measure the current values ​​of two phases of a three-phase, three-wire commercial frequency input AC current, performs a Fourier transform on the measured input AC current values, and detects the presence or absence of an open phase based on the results. In addition, a technology is known in which the instantaneous AC current value of a third phase, to which the current sensor is not attached, is calculated by subtracting the DC component from the current values ​​of the two phases at the same time to obtain an instantaneous AC current value, and then multiplying the instantaneous AC current values ​​of the two phases by minus one and adding the result. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-227073 [Patent Document 2] Patent No. 6334993 Summary of the Invention [Problem to be solved by the invention]

[0005] While the above-described techniques usually pose no particular problems, the inventors have found that when a malfunction is detected, it is not clear whether the malfunction is on the power supply side or the load side, and therefore it takes time and effort to investigate the cause. Therefore, it is desirable to be able to determine whether the malfunction is on the power supply side or the load side.

[0006] The present invention provides a fault detection device capable of detecting whether a fault is on the power supply side or the load side. reference The purpose is to realize a liquid supply device. [Means for solving the problem]

[0007] A fault detection device according to one aspect of the present invention includes a voltage detection unit, a current detection unit, and a fault detection unit. The voltage detection unit detects three-phase line voltage waveforms based on three-phase AC voltages input to a power conversion device that supplies power to a load device, such as a motor that drives a liquid supply device, typically a pump device. The current detection unit detects current waveforms for at least two phases of the three-phase AC current output from the power conversion device. The fault detection unit analyzes the outputs of the voltage detection unit and the current detection unit to distinguish between a fault on the power supply side and a fault on the load side relative to the power conversion device. The fault detection unit may calculate a power supply voltage unbalance rate based on the output of the voltage detection unit, and detect a fault on the power supply side related to the power supply voltage unbalance rate when the power supply voltage unbalance rate is greater than a first threshold. The fault detection unit may calculate a power supply voltage unbalance rate based on the output of the voltage detection unit, calculate a current unbalance rate based on the output of the current detection unit, and detect a fault on the load side related to the current unbalance rate when the power supply voltage unbalance rate is equal to or less than a first threshold and the current unbalance rate is greater than a second threshold. The fault detection unit may calculate the current waveform of the undetected phase based on the instantaneous currents in the current waveforms for the two phases and the sum of the instantaneous currents for three phases including the instantaneous currents being zero when the output of the current detection unit indicates current waveforms for two phases, and may detect the fault on the load side related to an open phase when a current waveform in which a sine waveform is not detected exists based on the current waveforms for three phases obtained from the output of the current detection unit, or when the ratio of the current value of one of the three phases to the current value of the other phases is equal to or less than a third threshold.

[0009] A liquid supply device according to yet another aspect of the present invention includes a fault detection device, a power conversion device, and a load device. [Effects of the Invention]

[0010] According to the present invention, it is possible to detect whether the problem is on the power supply side or on the load side. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram illustrating the configuration of a pump device equipped with a malfunction detection device according to an embodiment; [Figure 2] 10 is a flowchart illustrating an example of operation according to an embodiment. [Figure 3] 3 is a flowchart for explaining step ST30 in FIG. 2. [Figure 4] 3 is a flowchart for explaining step ST50 in FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, the embodiments will be described with reference to the drawings. Hereinafter, elements that are identical or similar to elements already described will be designated by the same or similar reference numerals, and duplicate descriptions will generally be omitted. For example, when there are multiple identical or similar elements, a common reference numeral may be used to describe each element without distinguishing between them, or a subnumber and / or lowercase alphabetic character may be used in addition to the common reference numeral to describe each element distinctly.

[0013] For convenience, the following description will use a pump device as an example of the liquid supply device. However, the liquid supply device is not limited to a pump device that supplies a liquid such as tap water, sewage, wastewater, hot spring water, or seawater to a destination. It may also be a water treatment device that has a raw water pump and removes impurities from the raw water supplied by the raw water pump. When the liquid supply device is a pump device, a motor drives the pump. When the liquid supply device is a water treatment device, the motor drives the raw water pump. Furthermore, the pump device will be described using a submersible pump installed in a water tank or well, but the pump device is not limited to a submersible pump and may be a pump directly connected to a water main. Furthermore, while the description will use an inverter as an example of a power conversion device, any AC-AC conversion type power conversion device can be used. For example, an AC-AC conversion type power conversion device may be an indirect conversion type device that uses DC, such as an inverter including a rectifier circuit, or a direct conversion type device that does not use DC, such as a matrix converter. Furthermore, the power conversion device will be described as being held by a control panel, but it may be disposed at a location away from the control panel without being held by the control panel.

[0014] 1 is a schematic diagram illustrating the configuration of a pump device according to one embodiment. This pump device 1 includes a vertical-shaft multi-stage pump 11 that is placed underwater in a well or the like, a motor 12 connected to the pump 11, and a power converter 21 that supplies power to the motor 12 via cables 13 for each phase. The power converter 21 is housed in a control panel 20, and a three-phase, three-wire AC power supply 30 is connected to the input side of the power converter 21 via power supply wiring 14 for each phase. The pump device 1 is an example of a liquid supply device.

[0015] Here, pump 11 is a multi-stage submersible pump for deep wells, placed in, for example, a well, with at least a portion of it located below the surface of the fluid in the well, such as well water. Pump 11 has a rotating shaft, which is connected to the rotor shaft of motor 12. When power is supplied to motor 12, which is placed underwater in a well or the like, the rotor in motor 12 rotates, and the rotating shaft rotates in response to this rotation. The rotation of the rotating shaft of pump 11 rotates impellers in multiple casings, increasing the pressure of the water in the casings and sending the water from the discharge casing to the secondary side of pump 11.

[0016] Motor 12 is, for example, a submersible motor, and is placed, for example, in well water directly below pump 11. Motor 12 is connected to power conversion device 21 via cable 13. When power is supplied from power conversion device 21 via cable 13, the rotor of motor 12 rotates, and the rotation of the rotor of pump 11 rotates in response to the rotation, thereby driving pump 11. Motor 12 is an example of a load device.

[0017] The control panel 20 includes a power conversion device 21, a control unit 22, a memory unit 26, a communication unit 27, an input unit 28, a display unit 29, and a speaker 29a. The control unit 22 includes a voltage detection unit 23, an R-phase current detection circuit 24R, a T-phase current detection circuit 24T, and a microcomputer 25. The control unit 22 is an example of a malfunction detection device. The control unit 22, the display unit 29, and / or the speaker 29a are another example of a malfunction detection device. The control unit 22 and the power conversion device 21 are an example of a control panel. The control unit 22, the power conversion device 21, the display unit 29, and / or the speaker 29a are another example of a control panel. The malfunction detection device, the power conversion device 21, and the motor 12 are an example of a liquid supply device. The control panel including the malfunction detection device and the power conversion device, and the load device which is the motor 12 are another example of a liquid supply device.

[0018] The power conversion device 21 is controlled by the control unit 22, converts the power supplied from the AC power supply 30 via the power supply wiring 14, and supplies the converted power to the motor 12 via the cable 13. The power conversion device 21 is configured to be able to vary the output frequency, i.e., the operating frequency of the motor 12. The power conversion device 21 does not necessarily have to be housed in the control panel 20, and may be arranged outside the control panel 20.

[0019] The voltage detection unit 23 detects the three-phase line voltage waveforms based on the three-phase AC voltages input to the power conversion device 21 that supplies power to a load device, which is the motor 12 that drives the pump 11. Specifically, the voltage detection unit 23 detects the three-phase line voltage waveforms from the power supply wiring 14 between the AC power source 30 and the power conversion device 21.

[0020] The R-phase current detection circuit 24R and the T-phase current detection circuit 24T detect current waveforms for two phases out of the three-phase AC current output from the power conversion device 21. Specifically, the R-phase current detection circuit 24R detects the R-phase current waveform from the cable 13 between the power conversion device 21 and the motor 12 via a current transformer CT_R. Similarly, the T-phase current detection circuit 24T detects the T-phase current waveform from the cable 13 between the power conversion device 21 and the motor 12 via a current transformer CT_T. However, without being limited to these, the control unit 22 may further include an S-phase current detection circuit. The R-phase current detection circuit 24R and the T-phase current detection circuit 24T are examples of current detection units that detect current waveforms for at least two phases out of the three-phase AC current output from the power conversion device 21.

[0021] The microcomputer 25 is a control center that controls all the components in the control panel 20, and includes a memory (not shown) that stores programs and data, and a processor (not shown) that executes processing based on the programs and data stored in the memory, thereby achieving various control functions. Note that the microcomputer 25 may be a CPU (central processing unit), GPU (graphics processing unit), FPGA (field programmable gate array), DSP (digital signal processor), or other general-purpose or dedicated processor.

[0022] The various control functions realized by the microcomputer 25 include, for example, a control function 25a for controlling a pump and a malfunction detection function 25b for detecting malfunctions. The malfunction detection function 25b is an example of a malfunction detection unit.

[0023] The control function 25a controls the power conversion device 21 based on input from the communication unit 27 or the input unit 28, thereby controlling the rotation of the motor 12 that drives the pump 11. Furthermore, when a malfunction is detected by the malfunction detection function 25b, the control function 25a controls the power conversion device 21 to stop the motor 12 that drives the pump 11.

[0024] The fault detection function 25b analyzes the output of the voltage detection unit 23 and the outputs of the R-phase current detection circuit 24R and the T-phase current detection circuit 24T to distinguish and detect whether the fault is on the power supply side or the load side of the power conversion device 21. Note that the fault detection function 25b may include the following functions (i) to (vii) as appropriate.

[0025] (i) When the output of the current detection unit (24R, 24T) indicates a current waveform for two phases, a function of calculating the current waveform for one phase that has not been detected based on the instantaneous current of each of the current waveforms for those two phases and the fact that the sum of the instantaneous currents for three phases including each of the instantaneous currents is zero.

[0026] (ii) A function of calculating a power supply voltage unbalance rate based on the output of the voltage detection unit 23, and detecting a power supply-side malfunction related to the power supply voltage unbalance rate when the power supply voltage unbalance rate is greater than a first threshold value.

[0027] (iii) A function of calculating a power supply voltage unbalance rate based on the output of the voltage detection unit 23, calculating a current unbalance rate based on the output of the current detection unit, and detecting a load-side malfunction related to the current unbalance rate when the power supply voltage unbalance rate is equal to or less than a first threshold value and the current unbalance rate is greater than a second threshold value.

[0028] (iv) A function of detecting a line voltage where no sine waveform is detected based on the output of the voltage detection unit 23, and deriving the R phase, S phase, or T phase that is in a missing phase state among the three phases according to the detected line voltage, thereby detecting a malfunction on the power supply side related to a missing phase.

[0029] (v) A function for detecting a load-side malfunction related to a missing phase when there is a current waveform in which a sine waveform is not detected based on the three-phase current waveforms obtained from the output of the current detection unit (24R, 24T), or when the ratio of the current value of any of the three phases to the current value of the other phases is equal to or less than a third threshold value.

[0030] (vi) A function that detects the phase sequence of the three-phase line voltage waveforms and detects a fault on the power supply side related to the reverse phase if the phase sequence is reversed.

[0031] (vii) A function of detecting the above-mentioned power supply malfunction in each of the stopped and operating states of the load device, which is the motor 12 that drives the pump 11.

[0032] The storage unit 26 is, for example, an EEPROM (registered trademark) (Electrically Erasable Programmable Read-Only Memory) or an HDD (Hard Disk Drive). The storage unit 26 stores data that is not stored in the memory of the microcomputer 25. For example, the storage unit 26 stores data for long-term storage rather than data used for real-time control, such as a log of operation data of the pump device 1, a log of malfunction detection, and maintenance information. However, the storage unit 26 is not limited to this, and may store data used for real-time control, such as control parameters and thresholds.

[0033] The communication unit 27 is an arbitrary communication interface controlled by the control unit 22 and capable of communicating with an external device such as a communication terminal using a wireless communication technology. Specifically, the communication unit 27 can be connected to an external device such as a communication terminal using, for example, a (short-range) wireless communication technology such as the Bluetooth (registered trademark) Low Energy standard (hereinafter also referred to as the BLE standard), Wi-Fi (registered trademark), or NFC, or a wired communication technology such as USB. The communication unit 27 may also wirelessly connect a speaker 29a, a microphone, etc. using the BLE standard. Note that the BLE standard may be BLE version 4.0 or higher and may be compatible with the BLE communication method. Accordingly, the "BLE standard" may also be referred to as the "Bluetooth 4.0 or higher standard."

[0034] The input unit 28 may include, for example, a device for receiving user input, such as an operation panel or touch screen including button switches and select switches, and sensors such as a water level sensor and a float switch (not shown). The select switch is used to input a pump operation command, and a switch for switching the pump between automatic, stop, and manual modes can be used as appropriate in response to user operation.

[0035] Display unit 29 may include a display device such as a liquid crystal display or an organic EL display that displays moving images, still images, text, alarms, etc. in accordance with processing by microcomputer 25, or an LED (Light Emitting Diode) lighting unit that displays the status of pump device 1. The display device may also have the functions of input unit 28, such as a touch screen. Display unit 29 is an example of an output unit that outputs an alarm regarding a malfunction detected by the malfunction detection unit.

[0036] The speaker 29a is a device that outputs audio such as alarms or guides based on audio information sent from the control unit 22, and may be embedded in the control panel 20, placed on the floor, or hung on a wall. The speaker 29a can be connected to the control unit 22 via a wire or wirelessly. The speaker 29a is another example of an output unit that outputs an alarm regarding a malfunction detected by the malfunction detection unit.

[0037] Next, an example of the operation of the pump device configured as described above will be described with reference to the flowcharts of Figures 2 to 4. This example of operation includes an example of the overall operation (Figure 2), an example of operation related to fault detection on the power supply side (Figure 3), and an example of operation related to fault detection on the load side (Figure 4). Each example of operation will be described in turn below.

[0038] (Stopped state before motor starts) Now, it is assumed that the water level detected by a water level sensor (not shown) in the pump device 1 is within a normal range, and the motor 12 that drives the pump 11 is in a stopped state before starting.

[0039] In step ST10, in the control panel 20 of the pump device 1, the voltage detection unit 23 detects the line voltage waveforms for the three phases based on the three-phase AC voltages input to the power conversion device 21. Specifically, the voltage detection unit 23 detects the line voltage waveforms for the three phases from the power supply wiring 14 between the AC power source 30 and the power conversion device 21.

[0040] After step ST10, in step ST20, in the control panel 20, the R-phase current detection circuit 24R and the T-phase current detection circuit 24T detect current waveforms for two phases of the three-phase AC current output from the power conversion device 21. However, since the motor 12 is currently in a stopped state before starting, no current waveforms are detected.

[0041] After step ST20, in steps ST30 to ST50, the microcomputer 25 in the control panel 20 analyzes the output of the voltage detection unit 23 and the outputs of the R-phase current detection circuit 24R and the T-phase current detection circuit 24T to distinguish and detect whether the problem is on the power supply side or the load side relative to the power conversion device 21. However, since the motor 12 is currently in a stopped state before starting, the analysis of the current waveform in step ST50 is not executed.

[0042] Therefore, in step ST30, the microcomputer 25 analyzes the output of the voltage detection unit 23 to detect a case where a malfunction is occurring on the power supply side rather than the power conversion device 21. This step ST30 includes steps ST31 to ST37 as shown in FIG.

[0043] In step ST31, the microcomputer 25 determines whether there is a line voltage where no sine waveform is detected based on the output of the voltage detection unit 23, and if the result of the determination is that no line voltage where no sine waveform is detected is detected (ST31: Yes), the microcomputer 25 proceeds to step ST32.

[0044] In step ST32, the microcomputer 25 detects a power supply malfunction related to the missing phase by deriving the R phase, S phase, or T phase that is in a missing phase state among the three phases according to the detected line voltage. In the case of a malfunction related to a missing phase on the power supply side, a malfunction in the AC power supply 30 from the electric power company or the power supply wiring 14 can be suspected when investigating the cause. After step ST32, step ST30 ends, and the process proceeds to step ST40. On the other hand, if the result of the determination in step ST31 is that there is no line voltage in which a sinusoidal waveform is not detected (ST31: No), the process proceeds to step ST33.

[0045] In step ST33, the microcomputer 25 detects the phase sequence of the line voltage waveforms for the three phases based on the output of the voltage detection unit 23, and determines whether the phase sequence has been reversed. If the determination result shows that the phase sequence has been reversed (ST33: Yes), the microcomputer 25 detects a problem on the power supply side related to the reversed phase (step ST34). Note that in the case of a problem related to the reversed phase on the power supply side, an incorrect wiring of the power supply wiring 14 can be suspected when investigating the cause. After step ST34, step ST30 ends, and the process proceeds to step ST40.

[0046] On the other hand, if the result of the determination in step ST33 is that the phase sequence has not been reversed (ST33: No), the process proceeds to step ST35.

[0047] In step ST35, the microcomputer 25 calculates the power supply voltage unbalance rate based on the output of the voltage detection unit 23.

[0048] After step ST35, in step ST36, the microcomputer 25 determines whether the power supply voltage unbalance rate is greater than the first threshold value. If the result of the determination is that the power supply voltage unbalance rate is greater than the first threshold value (ST36: Yes), the microcomputer 25 detects a power supply-side malfunction related to the power supply voltage unbalance rate (step ST37). Note that in the case of a malfunction related to the power supply-side voltage imbalance, a malfunction in the AC power supply 30 from the electric power company or the power supply wiring 14 can be suspected when investigating the cause. After step ST37, step ST30 ends, and the process proceeds to step ST40.

[0049] On the other hand, if the result of the determination in step ST36 is that the power supply voltage unbalance rate is equal to or less than the first threshold value (ST36: No), the microcomputer 25 ends step ST30 without detecting a problem on the power supply side, and proceeds to step ST40.

[0050] 2, in step ST40, the microcomputer 25 determines whether the load device, which is the motor 12 that drives the pump 11, is in an operating state, and if so, proceeds to step ST50. Since the motor 12 is currently in a stopped state before starting, step ST50 is skipped and the process proceeds to step ST60.

[0051] In step ST60, the microcomputer 25 determines whether a malfunction on the power supply side has been detected, depending on whether step ST32, ST34, or ST37 has been executed, for example. If the result of the determination is no, the process proceeds to step ST70.

[0052] In step ST70, the microcomputer 25 determines whether or not a malfunction on the load side was detected in step ST50. If the result of the determination is no, the process returns to step ST10, and the processes of steps ST10 to ST70 are repeatedly executed.

[0053] On the other hand, if the result of the determination in step ST60 is that a malfunction on the power supply side is detected, the process proceeds to step ST80. Similarly, if the result of the determination in step ST70 is that a malfunction on the load side is detected, the process proceeds to step ST80.

[0054] In step ST80, the microcomputer 25 causes the display unit 29 and the speaker 29a to output an alarm. The display unit 29 displays, for example, an LED indicating the alarm. The speaker 29a outputs a buzzer sound or a message indicating the alarm.

[0055] In parallel with step ST80, in step ST90, the microcomputer 25 stops the operation of the load device, which is the motor 12. Since the motor 12 is currently in a stopped state before starting, the stopped state of the motor 12 is maintained. After step ST90, the process returns to step ST10, and the processing of steps ST10 to ST90 is repeatedly executed.

[0056] (Operating state after motor start) Now, it is assumed that the pump device 1 is in an operating state after the water level detected by a water level sensor (not shown) is within a normal range and the motor 12 that drives the pump 11 has been started.

[0057] In step ST10, in the control panel 20 of the pump device 1, the voltage detection unit 23 detects the line voltage waveforms for the three phases based on the AC voltages for the three phases input to the power conversion device 21, in the same manner as described above.

[0058] After step ST10, in step ST20, in the control panel 20, the R-phase current detection circuit 24R and the T-phase current detection circuit 24T detect the current waveforms of two phases of the three-phase AC current output from the power conversion device 21.

[0059] After step ST20, in steps ST30 to ST50, in the control panel 20, the microcomputer 25 analyzes the output of the voltage detection unit 23 and the outputs of the R-phase current detection circuit 24R and the T-phase current detection circuit 24T to distinguish and detect whether the malfunction is on the power supply side or the load side of the power conversion device 21.

[0060] First, steps ST30 to ST40 are executed in the same manner as described above. In step ST40, microcomputer 25 determines whether or not the load device, which is motor 12 that drives pump 11, is in operation. Since motor 12 is in operation, the process proceeds to step ST50.

[0061] In step ST50, the microcomputer 25 analyzes the outputs of the R-phase current detection circuit 24R and the T-phase current detection circuit 24T to detect a malfunction on the load side of the power conversion device 21. This step ST50 includes steps ST51 to ST57 as shown in FIG.

[0062] In step ST51, the microcomputer 25 calculates the current waveform of the undetected S-phase based on the current waveforms for two phases indicated by the outputs of the R-phase current detection circuit 24R and the T-phase current detection circuit 24T. That is, the microcomputer 25 calculates the current waveform for the undetected one phase based on the instantaneous currents in the current waveforms for the two phases and the fact that the sum of the instantaneous currents for three phases including the instantaneous currents is zero. In this way, the microcomputer 25 obtains the current waveforms for three phases.

[0063] After step ST51, in step ST52, the microcontroller 25 determines whether there is a current waveform in which a sinusoidal waveform is not detected based on the obtained current waveforms for the three phases, and if not (ST52: No), proceeds to step ST53.

[0064] In step ST53, the microcontroller 25 determines, based on the obtained current waveforms for the three phases, whether the ratio of the current value of any of the three phases to the current values ​​of the other phases is less than or equal to a third threshold value, and if not (ST53: No), proceeds to step ST55.

[0065] On the other hand, if the results of the judgments in steps ST52 and ST53 indicate that there is a current waveform in which a sine waveform is not detected (ST52: Yes), or if the ratio of the current value of any of the three phases to the current values ​​of the other phases is equal to or less than the third threshold value (ST53: Yes), the process proceeds to step ST54.

[0066] In step ST54, the microcomputer 25 detects a load-side malfunction related to a missing phase (step ST54). In the case of a malfunction related to a missing phase on the load side, when investigating the cause, a disconnection or wiring malfunction of the motor 12 or cable 13 can be suspected. After step ST54, step ST50 is terminated and the process proceeds to step ST60.

[0067] On the other hand, if the result of the determination in step ST53 is negative, then in step ST55, the microcomputer 25 calculates the current unbalance rate based on the obtained current waveforms for the three phases.

[0068] After step ST55, in step ST56, the microcomputer 25 determines whether the current imbalance rate is greater than the second threshold. If the result of the determination is that the current imbalance rate is greater than the second threshold (ST56: Yes), the microcomputer 25 detects a load-side problem related to the current imbalance rate (step ST57). If the problem is related to the load-side current imbalance, a disconnection or wiring problem in the motor 12 or cable 13 can be suspected when investigating the cause. Note that step ST57 is executed when the power supply voltage imbalance rate is equal to or less than the first threshold (ST36: No) and when the current imbalance rate is greater than the second threshold (ST56: Yes).

[0069] After step ST57, step ST50 ends and the process proceeds to step ST60. On the other hand, if the result of the determination in step ST56 is that the current imbalance rate is equal to or less than the second threshold value (ST56: No), the microcomputer 25 does not detect a malfunction on the load side and ends step ST50, and the process proceeds to step ST60.

[0070] Thereafter, the process proceeds to step ST60 in the same manner as described above.

[0071] As described above, one embodiment of the present invention includes a voltage detection unit, a current detection unit, and a fault detection unit. The voltage detection unit detects three-phase line voltage waveforms based on three-phase AC voltages input to a power conversion device that supplies power to a load device, which is a motor that drives a liquid supply device. The current detection unit detects current waveforms for at least two phases of the three-phase AC current output from the power conversion device. The fault detection unit analyzes the output of the voltage detection unit and the output of the current detection unit to distinguish and detect whether the fault is on the power supply side or the load side of the power conversion device. This makes it possible to realize a fault detection device that can detect whether the fault is on the power supply side or the load side. Furthermore, since it is only necessary to investigate either the power supply side or the load side when investigating the cause of a fault, the time required for the investigation can be shortened compared to investigating both the power supply side and the load side. For example, when detecting imbalance, missing phase, or reverse phase, it is possible to clarify from the perspective of the control panel 20 whether the problem is on the "power supply side" (power supply quality or power supply wiring) or on the "load side" (motor, cable, or customer wiring), thereby shortening the time required to investigate the cause after a problem is detected.

[0072] Furthermore, according to one embodiment, when the output of the current detection unit indicates current waveforms for two phases, the fault detection unit may calculate the current waveform for one undetected phase based on the instantaneous currents of each of the current waveforms for the two phases and the fact that the sum of the instantaneous currents for three phases including each of the instantaneous currents is zero. In this case, in addition to the above-described advantageous effects, the hardware configuration for detecting the current waveform for one phase (e.g., an S-phase current transformer and an S-phase current detection circuit) can be omitted. In addition, the current waveforms for three phases can be obtained using the current transformers and current detection circuits for two phases.

[0073] According to one embodiment, the fault detection unit may calculate the power supply voltage unbalance rate based on the output of the voltage detection unit, and if the power supply voltage unbalance rate is greater than a first threshold, detect a power supply-side fault related to the power supply voltage unbalance rate. In this case, in addition to the above-described advantageous effects, it is possible to detect a power supply-side fault related to the power supply voltage unbalance rate.

[0074] According to one embodiment, the fault detection unit may calculate a power supply voltage unbalance rate based on the output of the voltage detection unit, calculate a current unbalance rate based on the output of the current detection unit, and detect a load-side fault related to the current unbalance rate when the power supply voltage unbalance rate is equal to or less than a first threshold value and the current unbalance rate is greater than a second threshold value. In this case, in addition to the above-described advantageous effects, it is possible to detect a load-side fault related to the current unbalance rate.

[0075] Furthermore, according to one embodiment, the malfunction detection unit may detect a line voltage where a sine waveform is not detected based on the output of the voltage detection unit, and derive which of the three phases is in a missing phase state, namely, R phase, S phase, or T phase, based on the detected line voltage, thereby detecting a malfunction on the power supply side related to a missing phase. In this case, in addition to the above-described advantageous effects, it is possible to detect a malfunction on the power supply side related to a missing phase.

[0076] Furthermore, according to one embodiment, the fault detection unit may detect a load-side fault related to a missing phase when, based on the three-phase current waveforms obtained from the output of the current detection unit, there is a current waveform in which a sine waveform is not detected, or when the ratio of the current value of any of the three phases to the current values ​​of the other phases is equal to or less than a third threshold value. In this case, in addition to the above-described advantageous effects, it is possible to detect a load-side fault related to a missing phase.

[0077] According to one embodiment, the fault detection unit may detect the phase sequence of the line voltage waveforms for three phases, and if the phase sequence is reversed, detect a fault on the power supply side related to the opposite phase. In this case, in addition to the above-described advantageous effects, it is possible to detect a fault on the power supply side related to the opposite phase (negative phase).

[0078] According to one embodiment, the malfunction detection unit may detect a malfunction on the power supply side when the load device is in a stopped state and in an operating state. In this case, in addition to the above-described advantageous effects, it is possible to detect a malfunction on the power supply side even when the load device is in a state before starting, regardless of whether the load device is started or not.

[0079] According to one embodiment, the device may further include an output unit that outputs an alarm regarding a malfunction detected by the malfunction detection unit. In this case, in addition to the above-described advantageous effects, the output unit can prompt the user to take action regarding the malfunction.

[0080] According to one embodiment, the power supply may further include a control unit that controls the load device to a stopped state when a malfunction is detected by the malfunction detection unit. In this case, in addition to the above-described advantageous effects, the load device can be protected from the detected malfunction.

[0081] According to one embodiment, a control panel including a fault detection device and a power conversion device may be provided, in which case a control panel that provides the above-described operational effects can be realized.

[0082] According to one embodiment, a liquid supply device may be provided that includes a malfunction detection device, a power conversion device, and a load device. In this case, it is possible to realize a liquid supply device that exhibits the above-described effects.

[0083] (Variation) Although the malfunction detection device according to one embodiment is mounted on the control panel of the liquid supply device, this is not limiting. For example, the malfunction detection device may be implemented as an inspection device that can be carried by maintenance personnel, rather than being mounted on the control panel. In this case, split current transformers CT_R and CT_T that can be retrofitted may be used. Alternatively, the current transformers CT_R and CT_T may be disposed on the cable 13 on the load side. In either case, if the malfunction detection device is not mounted on the control panel, the configuration of the liquid supply device and the control panel can be simplified.

[0084] In addition, in one embodiment, the power supply side malfunction can be detected as all of an open phase, a reversed phase, and a power supply voltage imbalance, but this is not limited to this. For example, it is sufficient that at least one of an open phase, a reversed phase, and a power supply voltage imbalance can be detected as a power supply side malfunction. Reducing the number of detection items can simplify the process of detecting a power supply side malfunction.

[0085] In addition, in one embodiment, the power supply side malfunctions are detected in the order of open phase, reverse phase, and power supply voltage imbalance, but this is not limiting. For example, the order in which power supply side malfunctions are detected may be changed to any other order. In this case, the degree of freedom in designing the process for detecting power supply side malfunctions can be improved.

[0086] In addition, in one embodiment, both a phase loss and a current imbalance can be detected as a load-side fault, but this is not limiting. For example, it is sufficient to detect either a phase loss or a power supply voltage imbalance as a load-side fault. In this case, the process of detecting a load-side fault can be simplified.

[0087] In addition, in one embodiment, the load-side faults are detected in the order of phase loss and current imbalance, but this is not limiting. For example, the order of detecting load-side faults may be changed to current imbalance and phase loss. In this case, the degree of freedom in designing the process for detecting load-side faults can be improved.

[0088] In addition, while the embodiment exemplifies a vertical-axis multi-stage pump 11, the present invention is not limited to this and may be applied to, for example, a horizontal-axis multi-stage pump, a vertical-axis single-stage pump, or a horizontal-axis single-stage pump. In addition, the embodiment exemplifies a submersible pump, but the present invention is not limited to this and may be applied to any pump device such as various land pumps, or any water treatment device having a raw water pump.

[0089] The above-described embodiments are merely illustrative examples for aiding in understanding the concept of the present invention, and are not intended to limit the scope of the present invention. Various components may be added, deleted, or converted to the embodiments without departing from the spirit of the present invention.

[0090] In the above-described embodiment, several functional units have been described, but these are merely examples of implementation of each functional unit. For example, multiple functional units described as being implemented in one device may be implemented across multiple separate devices, and conversely, multiple functional units described as being implemented across multiple separate devices may be implemented in one device.

[0091] Furthermore, the above-described malfunction detection device, control panel, and liquid supply device may be expressed as shown in the following [1] to [8]. Similarly, the pump control panel protection device shown in the following [1] to [8] may be expressed as a malfunction detection device, a control panel, or a liquid supply device.

[0092] [1] A pump control panel protection device that detects at least two-phase current waveforms and three-phase line voltage waveforms to protect the motor and control panel that operate the pump, and analyzes them with a microcomputer to determine whether the problem is on the power supply side or the load side. In this way, it is possible to clearly determine whether the problem is on the power supply side or the load side, thereby shortening the time required to investigate the cause after a problem is detected.

[0093] [2] In the above [1], when measuring the load current waveform using two-phase CTs (current transformers), the pump control panel protection device constantly calculates the current waveform of the phases not being measured using a microcomputer, using the instantaneous current relationship of "U phase + V phase + W phase = 0 [A]" in each waveform. In this way, three-phase AC current can be measured using two-phase CTs by utilizing the instantaneous current relationship of "U phase + V phase + W phase = 0 A."

[0094] [3] In the above [1] or [2], a pump control panel protection device calculates the power supply voltage imbalance rate by detecting the line voltage waveforms for three phases, and if it is greater than a preset power supply voltage imbalance rate malfunction judgment value, issues an alarm as a "power supply side voltage imbalance malfunction" or forcibly stops the pump to prevent operation. In this way, by detecting a power supply side voltage imbalance malfunction, it is possible to suspect a malfunction with the power company or the power supply wiring when investigating the cause.

[0095] [4] In the above [1] or [2], a pump control panel protection device calculates the power supply voltage unbalance rate by detecting three-phase line voltage waveforms and the current unbalance rate in three-phase current waveforms by detecting at least two-phase current waveforms, and if the calculated value is smaller than a preset power supply voltage unbalance rate malfunction judgment value and larger than a preset current unbalance rate malfunction judgment value, issues an alarm as a "load side current imbalance malfunction" and stops the pump to protect it. In this way, by detecting a load side imbalance rate malfunction, motor or cable malfunctions can be suspected when investigating the cause.

[0096] [5] In the above [1] or [2], a pump control panel protection device detects three-phase line voltage waveforms and, based on the line voltage where no sine waveform is detected, determines which of the R, S, or T phases is causing a power supply phase loss, and issues an alarm as a "power supply phase loss malfunction" or stops the pump to protect it. In this way, because it detects power supply voltage phase loss malfunctions, it can detect the malfunction even before the pump starts operating.

[0097] [6] In the above [1] or [2], a pump control panel protection device calculates the load side current in the current waveforms of three phases by detecting the current waveforms of at least two phases, and if a sine waveform is not detected or the ratio with the measurable current value of other phases is below a preset ratio, it determines that the phase is missing, and issues an alarm as a "load side missing phase fault" or stops the pump to protect it. In this way, since it detects a load side current missing phase fault, it is possible to suspect a motor, cable break, or wiring fault when investigating the cause.

[0098] [7] In the above [1] or [2], the phase sequence is confirmed by detecting the line voltage waveforms for three phases, and if the phase sequence is reversed, the power supply line is determined to be in a reverse phase (negative phase) connection, and an alarm is issued as a "power supply side reverse phase (negative phase) malfunction" or the pump is stopped to protect it. In this way, because the power supply side reverse phase is detected, the malfunction can be detected even before the pump starts operating.

[0099] [8] In the above [3], [5], or [7], a pump control panel protection device that issues an alarm or stops the pump to protect it if the judgment conditions are met even before the pump is started.

[0100] The present invention is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the invention. Furthermore, the embodiments may be implemented in appropriate combinations, in which case the combined effects can be obtained. Furthermore, the above-described embodiments include various inventions, and various inventions can be extracted by combining selected elements from the disclosed elements. For example, if the problem can be solved and the desired effect can be obtained even if some elements are deleted from all elements shown in the embodiments, the configuration from which these elements are deleted can be extracted as an invention. [Explanation of symbols]

[0101] 1 pump device, 11 pump, 12 motor, 13 cable, 14 power supply wiring, 20 control panel, 21 power conversion device, 22 control unit, 23 voltage detection unit, 24R R-phase current detection circuit, 24T T-phase current detection circuit, 25 microcomputer, 25a control function, 25b fault detection function, 26 memory unit, 27 communication unit, 28 input unit, 29 display unit, 29a speaker.

Claims

1. a voltage detection unit that detects three-phase line voltage waveforms based on three-phase AC voltages input to a power conversion device that supplies power to a load device, which is a motor that drives the liquid supply device; a current detection unit that detects current waveforms of at least two phases of the three-phase AC current output from the power conversion device; a fault detection unit that analyzes the output of the voltage detection unit and the output of the current detection unit to distinguish and detect whether the fault is on the power supply side or the load side of the power conversion device; Equipped with The fault detection unit calculates a power supply voltage unbalance rate based on the output of the voltage detection unit, and if the power supply voltage unbalance rate is greater than a first threshold, detects a fault on the power supply side related to the power supply voltage unbalance rate.

2. A voltage detection unit that detects the line voltage waveforms of three phases based on the three-phase AC voltages input to a power conversion device that supplies power to a load device, which is a motor that drives a liquid supply device; a current detection unit that detects current waveforms of at least two phases of the three-phase AC current output from the power conversion device; a fault detection unit that analyzes the output of the voltage detection unit and the output of the current detection unit to distinguish and detect whether the fault is on the power supply side or the load side of the power conversion device; Equipped with The fault detection unit calculates a power supply voltage unbalance rate based on the output of the voltage detection unit, calculates a current unbalance rate based on the output of the current detection unit, and detects a fault on the load side related to the current unbalance rate when the power supply voltage unbalance rate is equal to or less than a first threshold value and the current unbalance rate is greater than a second threshold value.

3. A voltage detection unit that detects the line voltage waveforms of the three phases based on the three phases of AC voltage input to a power conversion device that supplies power to a load device, which is a motor that drives a liquid supply device; a current detection unit that detects current waveforms of at least two phases of the three-phase AC current output from the power conversion device; a fault detection unit that analyzes the output of the voltage detection unit and the output of the current detection unit to distinguish and detect whether the fault is on the power supply side or the load side of the power conversion device; Equipped with The defect detection unit When the output of the current detection unit indicates the current waveforms for the two phases, the current waveform for the one phase that is not detected is calculated based on the instantaneous currents of each of the current waveforms for the two phases and the fact that the sum of the instantaneous currents for the three phases including each of the instantaneous currents is zero; If there is a current waveform in which a sine waveform is not detected based on the current waveforms for three phases obtained from the output of the current detection unit, or if the ratio of the current value of any of the three phases to the current values ​​of the other phases is equal to or less than a third threshold value, a malfunction on the load side related to an open phase is detected. Fault detection device.

4. When the output of the current detection unit indicates the current waveforms for the two phases, the malfunction detection unit calculates the current waveform for the one phase that has not been detected based on the instantaneous currents of each of the current waveforms for the two phases and the fact that the sum of the instantaneous currents for the three phases including each of the instantaneous currents is zero.

3. The fault detection device according to claim 1 or 2.

5. the malfunction detection unit calculates a power supply voltage unbalance rate based on an output of the voltage detection unit, and detects a malfunction on the power supply side related to the power supply voltage unbalance rate when the power supply voltage unbalance rate is greater than a first threshold value.

4. The fault detection device according to claim 2 or 3.

6. the fault detection unit calculates a power supply voltage unbalance rate based on an output of the voltage detection unit, calculates a current unbalance rate based on an output of the current detection unit, and detects a fault on the load side related to the current unbalance rate when the power supply voltage unbalance rate is equal to or less than a first threshold value and the current unbalance rate is greater than a second threshold value. The fault detection device according to claim 1 or 3.

7. The malfunction detection unit detects a line voltage where a sine waveform is not detected based on the output of the voltage detection unit, and derives an R phase, an S phase, or a T phase that is in a missing phase state among the three phases according to the detected line voltage, thereby detecting a malfunction on the power supply side related to a missing phase. The fault detection device according to any one of claims 1 to 6.

8. The malfunction detection unit detects a malfunction on the load side related to a missing phase when there is a current waveform in which a sine waveform is not detected based on the current waveforms for three phases obtained from the output of the current detection unit, or when a ratio of a current value of any one of the three phases to a current value of another phase is equal to or less than a third threshold value.

8. The fault detection device according to claim 5, wherein claim 3 is recited.

9. the malfunction detection unit detects a phase sequence of the line voltage waveforms for the three phases, and when the phase sequence is reversed, detects a malfunction on the power supply side related to the opposite phase. The fault detection device according to any one of claims 1 to 8.

10. the malfunction detection unit detects a malfunction on the power supply side in each of a stopped state and an operating state of the load device. A fault detection device according to claim 1, claim 7 or claim 9 which cites claim 1.

11. a control unit that, when a malfunction is detected by the malfunction detection unit, causes an output unit to output an alarm regarding the malfunction or controls the load device to a stopped state; The fault detection device according to any one of claims 1 to 10, further comprising:

12. A liquid supply device comprising the malfunction detection device according to any one of claims 1 to 10, a power conversion device, and a load device.

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