WO2013153596A1 - 地絡検出回路およびそれを用いた電力変換装置 - Google Patents
地絡検出回路およびそれを用いた電力変換装置 Download PDFInfo
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- WO2013153596A1 WO2013153596A1 PCT/JP2012/059670 JP2012059670W WO2013153596A1 WO 2013153596 A1 WO2013153596 A1 WO 2013153596A1 JP 2012059670 W JP2012059670 W JP 2012059670W WO 2013153596 A1 WO2013153596 A1 WO 2013153596A1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/40—Testing power supplies
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/40—Testing power supplies
- G01R31/42—AC power supplies
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/52—Testing for short-circuits, leakage current or ground faults
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/16—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to fault current to earth, frame or mass
- H02H3/162—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to fault current to earth, frame or mass for ac systems
- H02H3/165—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to fault current to earth, frame or mass for ac systems for three-phase systems
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
- H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
- H02H7/1216—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for AC-AC converters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M5/00—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases
- H02M5/40—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc
- H02M5/42—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters
- H02M5/44—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac
- H02M5/443—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a thyratron or thyristor type requiring extinguishing means
- H02M5/45—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
- H02P6/12—Monitoring commutation; Providing indication of commutation failure
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
- H02P6/24—Arrangements for stopping
Definitions
- the present invention relates to a ground fault detection circuit and a power converter using the same, and more particularly to a ground fault detection circuit for detecting a ground fault and a power converter using the ground fault detection circuit.
- the thyristor starter includes a converter that converts commercial-phase three-phase AC power into DC power, a DC reactor that smoothes the DC power, and DC power supplied from the converter via the DC reactor to three-phase power of a desired frequency. And an inverter that converts the AC power into the synchronous motor through first to third AC lines. By controlling the three-phase AC power applied to the synchronous motor, the stopped synchronous motor can be started and rotated at a predetermined rotational speed (see, for example, JP-A-2003-61380 (Patent Document 1)). ).
- such a thyristor starting device is provided with a ground fault detection circuit for detecting a ground fault.
- a ground fault detection circuit for detecting a ground fault.
- a three-phase transformer is connected to the first to third AC lines between the thyristor starter and the synchronous motor, and a ground fault is detected based on the output voltage of the three-phase transformer.
- a ground fault is detected based on the output voltage of the three-phase transformer.
- Patent Document 2 Japanese Patent Application Laid-Open No. 2009-131048
- Patent Document 3 Japanese Patent Application Laid-Open No. 2010-130704
- Patent Document 4 Japanese Patent Application Laid-Open No. 2011-130634
- one terminal of each of the first and second resistance elements is connected to two input terminals of the inverter, respectively, and a third resistance element is provided between the other terminals of the first and second resistance elements and the ground voltage line. , And the occurrence of a ground fault is detected based on the voltage across the terminals of the third resistance element (for example, “Thyristor starter for thermal power plant”, Mitsubishi Electric Technical Report, Vol. 67, No. 1). 5, 1993 (see Non-Patent Document 1).
- the ground fault detection circuits of Patent Documents 2 to 4 use a three-phase transformer, so there is a problem that the circuit is large and expensive. Further, the ground fault detection circuit of Non-Patent Document 1 has a problem that the detection accuracy is poor.
- a main object of the present invention is to provide a small-sized, low-cost, high-accuracy ground fault detection circuit and a power conversion device using the same.
- the ground fault detection circuit converts the first three-phase AC power into DC power, converts the DC power into the second three-phase AC power, and loads through the first to third AC lines.
- a ground fault detection circuit for detecting a ground fault in a power converter supplied to the power converter comprising first to fourth resistance elements. One terminal of each of the first to third resistance elements is connected to each of the first to third AC lines, and the other terminal of each of the first to third resistance elements is connected to one terminal of the fourth resistance element. The other terminal of the fourth resistance element receives a ground voltage.
- the ground fault detection circuit further includes a determination circuit that determines whether or not a ground fault has occurred in the power conversion device based on the voltage across the terminals of the fourth resistance element.
- the power converter according to the present invention also includes a converter that converts the first three-phase AC power into DC power, a DC reactor that smoothes the DC power, and DC power that is supplied from the converter via the DC reactor.
- the ground fault detection circuit includes first to fourth resistance elements. One terminal of each of the first to third resistance elements is connected to each of the first to third AC lines, and the other terminal of each of the first to third resistance elements is connected to one terminal of the fourth resistance element. The other terminal of the fourth resistance element receives a ground voltage.
- the ground fault detection circuit further includes a determination circuit that determines whether or not a ground fault has occurred in the power conversion device based on the voltage across the terminals of the fourth resistance element.
- the determination circuit determines that a ground fault has occurred in the power converter when the voltage between the terminals of the fourth resistance element exceeds a predetermined voltage.
- the determination circuit includes an absolute value calculator that calculates an absolute value of the voltage between the terminals of the fourth resistance element, and an absolute value of the voltage between the terminals of the fourth resistance element that is calculated by the absolute value calculator. And a comparator that outputs a signal indicating that a ground fault has occurred in the power conversion device when a predetermined value is exceeded.
- the frequency of the second three-phase AC power is changeable
- the load is a synchronous motor
- the power converter is a thyristor starter that starts the synchronous motor.
- the thyristor starter starts the synchronous generator of the power plant as a synchronous motor.
- one terminals of the first to third resistance elements are connected to the first to third AC lines, respectively, and the other terminals of the first to third resistance elements are both the fourth terminal.
- the other terminal of the fourth resistance element receives the ground voltage.
- the determination circuit determines whether a ground fault has occurred based on the voltage across the terminals of the fourth resistance element. When normal, no current flows through the fourth resistance element, and when a ground fault occurs, a current flows through the fourth resistance element, so that the occurrence of the ground fault can be detected with high accuracy.
- a three-phase transformer is not used, it is possible to reduce the size and cost of the device.
- FIG. 2 is a circuit block diagram illustrating a configuration of a ground fault detection circuit illustrated in FIG. 1. It is a circuit block diagram which shows the comparative example of embodiment. It is a time chart which shows the voltage change before and behind a ground fault when the R phase line shown in FIG. 2 has a ground fault. It is a time chart which shows the voltage change before and behind a ground fault when the high voltage side input terminal of the inverter shown in FIG. 2 has a ground fault.
- the thyristor starting device receives the three-phase AC power from the AC power source 1 and starts the synchronous motor 8.
- the three-phase transformer 2 converts a three-phase AC voltage having a commercial frequency from an AC power source (electric power system) 1 into a predetermined three-phase AC voltage.
- the three-phase AC voltage generated by the three-phase transformer 2 is supplied to the converter 3 via the U-phase line UL, the V-phase line VL, and the W-phase line WL.
- the converter 3 converts the three-phase AC power from the three-phase transformer 2 into DC power.
- the DC reactor 4 is connected between the high voltage side output terminal 3 a of the converter 3 and the high voltage side input terminal 5 a of the inverter 5, and smoothes the DC power generated by the converter 3.
- the low voltage side output terminal 3b of the converter 3 and the low voltage side input terminal 5b of the inverter 5 are directly connected.
- the DC reactor 4 may be connected between the low voltage side output terminal 3 b of the converter 3 and the low voltage side input terminal 5 b of the inverter 5. Further, the DC reactor 4 includes a high voltage side output terminal 3 a of the converter 3 and a high voltage side input terminal 5 a of the inverter 5, a low voltage side output terminal 3 b of the converter 3 and a low voltage side input terminal 5 b of the inverter 5. May be connected to each other.
- Inverter 5 converts DC power supplied from converter 3 via DC reactor 4 into three-phase AC power having a desired frequency, and converts the three-phase AC power into R-phase line RL, S-phase line SL, and T-phase. This is given to the synchronous motor 8 via the line TL.
- the synchronous motor 8 is rotationally driven by the three-phase AC power from the inverter 5.
- the rotational speed (number of revolutions / minute) of the synchronous motor 8 is gradually increased.
- the switching frequency of the inverter 5 is increased in accordance with the rotational speed of the synchronous motor 8. Thereby, the rotational speed of the synchronous motor 8 gradually increases from 0 to a predetermined value, and the frequency of the three-phase AC power gradually increases from 0 to a predetermined value.
- FIG. 2 is a circuit diagram showing the configuration of the converter 3 and the inverter 5.
- converter 3 includes thyristors 11-16.
- the anodes of thyristors 11 to 13 are connected to U-phase line UL, V-phase line VL, and W-phase line WL, respectively, and their cathodes are all connected to high-voltage side output terminal 3a.
- the cathodes of thyristors 14 to 16 are connected to U-phase line UL, V-phase line VL, and W-phase line WL, respectively, and their anodes are all connected to low-voltage side output terminal 3b.
- the thyristors 11 to 16 are controlled by the control circuit 7. By turning on the thyristors 11 to 16 at a predetermined timing, the three-phase AC power can be converted into DC power.
- the inverter 5 includes thyristors 21 to 26.
- the anodes of thyristors 21 to 23 are all connected to high-voltage side input terminal 5a, and their cathodes are connected to R-phase line RL, S-phase line SL, and T-phase line TL, respectively.
- the anodes of thyristors 24 to 26 are connected to R-phase line RL, S-phase line SL, and T-phase line TL, respectively, and their cathodes are all connected to low-voltage side input terminal 5b.
- the thyristors 21 to 26 are controlled by the control circuit 7. By turning on the thyristors 21 to 26 at a predetermined timing, it is possible to convert DC power into three-phase AC power having a desired frequency.
- the ground fault detection circuit 6 is a circuit that detects the occurrence of a ground fault in the thyristor starter. As shown in FIG. 3, the ground fault detection circuit 6 includes resistance elements 31 to 34, an amplifier 35, and a comparator 36.
- Resistive elements 31 to 33 have one terminals connected to R-phase line RL, S-phase line SL, and T-phase line TL, respectively, and their other terminals are all connected to node N31.
- One terminal of resistance element 34 is connected to node N31, and the other terminal of resistance element 34 is connected to a line of ground voltage GND.
- the amplifier 35 amplifies the inter-terminal voltage V31 of the resistance element 34.
- the comparator 36 compares the output voltage V35 of the amplifier 35 with a predetermined reference voltage VR, and outputs a signal ⁇ D having a level corresponding to the comparison result.
- the signal ⁇ D is set to the “L” level.
- signal ⁇ D is set to “H” level.
- a ground fault point for example, the R-phase line RL
- the other terminal the line of the ground voltage GND
- a loop through which a current flows is created.
- a voltage V31 is generated between the terminals of the resistance element 34.
- VR ⁇ V35, and the signal ⁇ D becomes the activation level “H” level.
- the control circuit 7 receives signals indicating the input current of the converter 3, the output voltage of the inverter 5, the rotational speed of the synchronous motor 8, and the like from a plurality of sensors (not shown), and the converter 3 and the inverter 5 are based on the received signals. To control.
- the control circuit 7 when starting the synchronous motor 8 in the stopped state, the control circuit 7 outputs the three-phase alternating current output from the inverter 5 as the rotational speed of the synchronous motor 8 gradually increases from 0 to a predetermined value.
- the power frequency is gradually increased from 0 to a predetermined value.
- the control circuit 7 stops the operation of the converter 3 and the inverter 5 and interrupts a plurality of circuit breakers (not shown).
- a plurality of circuit breakers not shown
- Such a thyristor starting device is used for starting a stopped synchronous generator as a synchronous motor in a power plant, for example. While the synchronous generator is driven to rotate at a predetermined rotational speed as a synchronous motor, the thyristor starter is disconnected from the synchronous generator and the synchronous generator is rotated by a gas turbine or the like to generate AC power.
- resistance elements 31 to 33 are connected between AC lines RL, SL, and TL and node N31, respectively, and resistance element 34 is connected between node N31 and a line of ground voltage GND. It is determined whether or not a ground fault has occurred on the basis of the inter-terminal voltage V31. When a ground fault has not occurred, the voltage V31 is about 0 V. When a ground fault has occurred, the voltage V31 is significantly higher than 0 V. Therefore, the occurrence of a ground fault must be detected with high accuracy. Can do. In addition, since a three-phase transformer is not used as in the prior art, it is possible to reduce the size and cost of the device.
- FIG. 4 is a circuit block diagram showing a configuration of a ground fault detection circuit 40 as a comparative example of the embodiment, and is a diagram contrasted with FIG.
- the ground fault detection circuit 40 includes resistance elements 41 to 43, an amplifier 44, and a comparator 45.
- Resistive elements 41 and 42 have one terminals connected to input terminals 5a and 5b of inverter 5, respectively, and the other terminals connected to node N41.
- One terminal of resistance element 43 is connected to node N41, and the other terminal of resistance element 43 is connected to the line of ground voltage GND.
- the amplifier 44 amplifies the terminal voltage V41 of the resistance element 43.
- the comparator 45 compares the output voltage V44 of the amplifier 44 with a predetermined voltage range VRL to VRH (VRL ⁇ VRH), and outputs a signal ⁇ D having a level corresponding to the comparison result.
- signal ⁇ D is set to “L” level.
- signal ⁇ D is set to “H” level.
- the voltage obtained by dividing the voltage between the input terminals 5a and 5b of the inverter 5 by the resistance elements 41 and 42 becomes the voltage V41 of the node N41.
- the voltage V41 is a voltage that has an amplitude with a certain width.
- VRL ⁇ V44 ⁇ VRH the signal ⁇ D becomes the “L” level of the inactivation level.
- a ground fault point for example, the R-phase line RL
- the other terminal of the resistance element 43 the line of the ground voltage GND
- a loop is formed in which a current flows.
- a voltage V41 is generated between the terminals of the resistance element 43.
- FIGS. 5A to 9A are time charts showing the output voltage V44 of the amplifier 44 of FIG. 4 (comparative example).
- FIGS. 5B to 9B are time charts showing the output voltage V35 of the amplifier 35 of FIG. 3 (embodiment).
- FIGS. 5C to 9C are time charts showing the voltage Vr of the R-phase line RL, the voltage Vs of the S-phase line SL, and the voltage Vt of the T-phase line TL in FIG. 5D to 9D show the voltage Vn of the low voltage side output terminal 3b (low voltage side input terminal 5b of the inverter 5) of the converter 3 of FIG. 4 is a time chart showing a voltage Vp1 and a voltage Vp2 of a high voltage side input terminal 5a of the inverter 5.
- the voltages Vr, Vs, Vt, Vn, Vp1, and Vp2 are the same in the comparative example and the embodiment.
- FIGS. 5A to 5D show voltage changes before and after a ground fault when the R-phase line RL has a ground fault at time t0.
- the three-phase AC voltages Vr, Vs, and Vt all change with a predetermined amplitude.
- the R-phase voltage Vr becomes 0V, and the amplitudes of the S-phase voltage Vs and the T-phase voltage Vt increase.
- each of the DC voltages Vn, Vp1, and Vp2 does not become a constant value even at normal time, and changes with a certain amplitude.
- the amplitudes of the DC voltages Vn, Vp1, and Vp2 increase.
- the output voltage V44 of the amplifier 44 of the comparative example changes according to the voltage obtained by dividing the DC voltage (Vp2-Vn). For this reason, as shown in FIG. 5A, the voltage V44 changes with a certain amplitude even when it is normal, and the amplitude of the voltage V44 increases when a ground fault occurs in the R-phase line RL at time t0. . Since the amplitude of the voltage V44 changes before and after time t0 in this way, it is possible to detect the occurrence of a ground fault. However, since the change before and after time t0 is small, it is not easy to determine whether a ground fault has occurred.
- the output voltage V35 of the amplifier 35 of the present embodiment changes according to the voltage obtained by adding the three-phase AC voltages Vr, Vs, and Vt. For this reason, as shown in FIG. 5B, the voltage V35 is about 0 V when it is normal, and the amplitude of the voltage V35 suddenly increases when a ground fault occurs in the R-phase line RL at time t0. Thus, since the amplitude of the voltage V35 changes significantly before and after the time t0, it is possible to easily determine whether or not a ground fault has occurred.
- FIGS. 6A to 6D show voltage changes before and after a ground fault when the high voltage side input terminal 5a of the inverter 5 has a ground fault at time t0.
- each of the DC voltages Vn, Vp1, and Vp2 does not have a constant value even at normal time, and changes with a certain amplitude.
- the DC voltage Vp2 becomes 0V, and both the DC voltages Vn and Vp1 shift to the negative voltage side.
- the three-phase AC voltages Vr, Vs, and Vt all change with a predetermined amplitude during normal operation. If a ground fault occurs at the high voltage side input terminal 5a of the inverter 5 at time t0, the three-phase AC voltages Vr, Vs, Vt are all shifted to the negative voltage side.
- the output voltage V44 of the amplifier 44 of the comparative example changes according to the voltage obtained by dividing the DC voltage (Vp2-Vn). For this reason, as shown in FIG. 6A, the voltage V44 changes with a certain amplitude even when it is normal, and when a ground fault occurs at the high voltage side input terminal 5a of the inverter 5 at time t0, the voltage V44. Shifts to the negative voltage side. Thus, since the voltage V44 is shifted before and after time t0, it is possible to detect the occurrence of a ground fault. However, since the change before and after time t0 is small, it is not easy to determine whether a ground fault has occurred. Further, since the amplitude of the voltage V44 decreases due to a ground fault, it is impossible to determine whether or not a ground fault has occurred based on the magnitude of the amplitude of the voltage V44.
- the output voltage V35 of the amplifier 35 of the present embodiment changes according to the voltage obtained by adding the three-phase AC voltages Vr, Vs, and Vt. For this reason, as shown in FIG. 6B, the voltage V35 is about 0V when it is normal, and the amplitude of the voltage V35 suddenly increases when a ground fault occurs at the high voltage side input terminal 5a of the inverter 5 at time t0. To do. Thus, since the amplitude of the voltage V35 changes significantly before and after the time t0, it is possible to easily determine whether or not a ground fault has occurred.
- each of the DC voltages Vn, Vp1, and Vp2 does not become a constant value even when normal, and changes with a certain amplitude.
- the DC voltage Vn becomes 0V, and both the DC voltages Vp1 and Vp2 shift to the positive voltage side.
- the three-phase AC voltages Vr, Vs, and Vt all change with a predetermined amplitude.
- the three-phase AC voltages Vr, Vs, Vt are all shifted to the positive voltage side.
- the output voltage V44 of the amplifier 44 of the comparative example changes according to the voltage obtained by dividing the DC voltage (Vp2-Vn). For this reason, as shown in FIG. 7A, the voltage V44 changes with a certain amplitude even when it is normal, and when a ground fault occurs at the low voltage side input terminal 5b of the inverter 5 at time t0, the voltage V44. Shifts to the positive voltage side. Thus, since the voltage V44 is shifted before and after time t0, it is possible to detect the occurrence of a ground fault. However, since the change before and after time t0 is small, it is not easy to determine whether a ground fault has occurred. Further, since the amplitude of the voltage V44 decreases due to a ground fault, it is impossible to determine whether or not a ground fault has occurred based on the magnitude of the amplitude of the voltage V44.
- the output voltage V35 of the amplifier 35 of the present embodiment changes according to the voltage obtained by adding the three-phase AC voltages Vr, Vs, and Vt. For this reason, as shown in FIG. 7B, the voltage V35 is about 0V when it is normal, and the amplitude of the voltage V35 suddenly increases when a ground fault occurs at the low voltage side input terminal 5b of the inverter 5 at time t0. To do. Thus, since the amplitude of the voltage V35 changes significantly before and after the time t0, it is possible to easily determine whether or not a ground fault has occurred.
- FIGS. 8A to 8D show voltage changes before and after a ground fault when the high voltage side output terminal 3a of the converter 3 has a ground fault at time t0.
- each of the DC voltages Vn, Vp1, and Vp2 does not become a constant value even at normal time, and changes with a certain amplitude.
- the DC voltage Vp1 becomes 0V, and both the DC voltages Vn and Vp2 shift to the negative voltage side.
- the three-phase AC voltages Vr, Vs, and Vt all change with a predetermined amplitude.
- the three-phase AC voltages Vr, Vs, Vt are all shifted to the negative voltage side.
- the output voltage V44 of the amplifier 44 of the comparative example changes according to the voltage obtained by dividing the DC voltage (Vp2-Vn). For this reason, as shown in FIG. 8A, the voltage V44 changes with a certain amplitude even when it is normal, and when a ground fault occurs at the high-voltage side output terminal 3a of the converter 3 at time t0, the voltage V44. Shifts to the negative voltage side. Thus, since the voltage V44 is shifted before and after time t0, it is possible to detect the occurrence of a ground fault. However, since the change before and after time t0 is small, it is not easy to determine whether a ground fault has occurred.
- the output voltage V35 of the amplifier 35 of the present embodiment changes according to the voltage obtained by adding the three-phase AC voltages Vr, Vs, and Vt. For this reason, as shown in FIG. 8B, the voltage V35 is about 0V when it is normal, and the amplitude of the voltage V35 suddenly increases when a ground fault occurs at the high voltage side output terminal 3a of the converter 3 at time t0. To do. Thus, since the amplitude of the voltage V35 changes significantly before and after the time t0, it is possible to easily determine whether or not a ground fault has occurred.
- FIG. 9A to 9D show voltage changes before and after the ground fault when the U-phase line UL has a ground fault at time t0.
- the three-phase AC voltages Vr, Vs, Vt all change with a predetermined amplitude.
- the amplitudes of the three-phase AC voltages Vr, Vs, and Vt increase.
- each of the DC voltages Vn, Vp1, and Vp2 does not become a constant value even at normal time, and changes with a certain amplitude.
- the amplitudes of the DC voltages Vn, Vp1, and Vp2 increase.
- the output voltage V44 of the amplifier 44 of the comparative example changes according to the voltage obtained by dividing the DC voltage (Vp2-Vn). Therefore, as shown in FIG. 9A, the voltage V44 changes with a certain amplitude even when it is normal, and the amplitude of the voltage V44 increases when a ground fault in the U-phase line UL occurs at time t0. . Since the amplitude of the voltage V44 changes before and after time t0 in this way, it is possible to detect the occurrence of a ground fault. However, since the change before and after time t0 is small, it is not easy to determine whether a ground fault has occurred.
- the output voltage V35 of the amplifier 35 of the present embodiment changes according to the voltage obtained by adding the three-phase AC voltages Vr, Vs, and Vt. For this reason, as shown in FIG. 9B, the voltage V35 is about 0 V when it is normal, and the amplitude of the voltage V35 suddenly increases when a ground fault occurs in the U-phase line UL at time t0. Thus, since the amplitude of the voltage V35 changes significantly before and after the time t0, it is possible to easily determine whether or not a ground fault has occurred.
- FIG. 10 is a circuit block diagram showing a configuration of a ground fault detection circuit 50 which is a modified example of the present embodiment, and is a diagram to be compared with FIG.
- a ground fault detection circuit 50 according to this modification is obtained by adding an absolute value calculator 51 and a filter circuit 52 between amplifier 35 and comparator 36 of ground fault detection circuit 6 of FIG. It is.
- the absolute value calculator 51 calculates an absolute value
- the filter circuit 52 is a low-pass filter that removes a high frequency component from the output voltage V51 of the absolute value calculator 51.
- the comparator 36 compares the output voltage V52 of the filter circuit 52 with a predetermined reference voltage VR, and outputs a signal ⁇ D having a level corresponding to the comparison result.
- the signal ⁇ D When the output voltage V52 of the filter circuit 52 is smaller than the reference voltage VR (V52 ⁇ VR), the signal ⁇ D is set to the “L” level. When output voltage V52 of filter circuit 52 is higher than reference voltage VR (VR ⁇ V52), signal ⁇ D is set to “H” level. In this modified example, the occurrence of the ground fault can be easily and accurately detected regardless of whether the output voltage V35 of the amplifier 35 becomes a positive voltage or a negative voltage due to the ground fault.
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Description
Claims (9)
- 第1の三相交流電力を直流電力に変換し、前記直流電力を第2の三相交流電力に変換し、第1~第3の交流ライン(RL,SL,TL)を介して負荷(8)に供給する電力変換装置において地絡事故を検出する地絡検出回路(6)であって、
第1~第4の抵抗素子(31~34)を備え、
前記第1~第3の抵抗素子(31~33)の一方端子はそれぞれ前記第1~第3の交流ライン(RL,SL,TL)に接続され、前記第1~第3の抵抗素子(31~33)の他方端子はともに前記第4の抵抗素子(34)の一方端子に接続され、前記第4の抵抗素子(34)の他方端子は接地電圧を受け、
さらに、前記第4の抵抗素子(34)の端子間電圧に基づいて、前記電力変換装置において前記地絡事故が発生したか否かを判別する判別回路(36)を備える、地絡検出回路。 - 前記判別回路(36)は、前記第4の抵抗素子(34)の端子間電圧が予め定められた電圧を超えた場合に、前記電力変換装置において前記地絡事故が発生したと判別する、請求項1に記載の地絡検出回路。
- 前記判別回路(36,51)は、
前記第4の抵抗素子(34)の端子間電圧の絶対値を求める絶対値演算器(51)と、
前記絶対値演算器(51)によって求められた前記第4の抵抗素子(34)の端子間電圧の絶対値が予め定められた値を超えた場合に、前記電力変換装置において前記地絡事故が発生したことを示す信号を出力する比較器(36)とを含む、請求項2に記載の地絡検出回路。 - 前記第2の三相交流電力の周波数は変更可能になっていて、
前記負荷は同期電動機(8)であり、
前記電力変換装置は、前記同期電動機(8)を起動させるサイリスタ起動装置である、請求項1に記載の地絡検出回路。 - 電力変換装置であって、
第1の三相交流電力を直流電力に変換するコンバータ(3)と、
前記直流電力を平滑化させる直流リアクトル(4)と、
前記コンバータ(3)から前記直流リアクトル(4)を介して与えられた前記直流電力を第2の三相交流電力に変換し、第1~第3の交流ライン(RL,SL,TL)を介して負荷に供給するインバータ(5)と、
前記電力変換装置の地絡事故を検出する地絡検出回路(6)と、
前記地絡検出回路(6)によって前記地絡事故が検出された場合に前記電力変換装置の運転を停止させる制御回路(7)とを備え、
前記地絡検出回路(6)は、
第1~第4の抵抗素子(31~34)を含み、
前記第1~第3の抵抗素子(31~33)の一方端子はそれぞれ前記第1~第3の交流ライン(RL,SL,TL)に接続され、前記第1~第3の抵抗素子(31~33)の他方端子はともに前記第4の抵抗素子(34)の一方端子に接続され、前記第4の抵抗素子(34)の他方端子は接地電圧を受け、
さらに、前記第4の抵抗素子(34)の端子間電圧に基づいて、前記電力変換装置において前記地絡事故が発生したか否かを判別する判別回路(36)を含む、電力変換装置。 - 前記判別回路(36)は、前記第4の抵抗素子(34)の端子間電圧が予め定められた電圧を超えた場合に、前記電力変換装置において前記地絡事故が発生したと判別する、請求項5に記載の電力変換装置。
- 前記判別回路(36,51)は、
前記第4の抵抗素子(34)の端子間電圧の絶対値を求める絶対値演算器(51)と、
前記絶対値演算器(51)によって求められた前記第4の抵抗素子(34)の端子間電圧の絶対値が予め定められた値を超えた場合に、前記電力変換装置において前記地絡事故が発生したことを示す信号を出力する比較器(36)とを含む、請求項6に記載の地絡検出回路。 - 前記第2の三相交流電力の周波数は変更可能になっていて、
前記負荷は同期電動機(8)であり、
前記電力変換装置は、前記同期電動機(8)を起動させるサイリスタ起動装置である、請求項5に記載の電力変換装置。 - 前記サイリスタ起動装置は、発電所の同期発電機を前記同期電動機(8)として起動させる、請求項8に記載の電力変換装置。
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PCT/JP2012/059670 WO2013153596A1 (ja) | 2012-04-09 | 2012-04-09 | 地絡検出回路およびそれを用いた電力変換装置 |
EP12874321.8A EP2837942B1 (en) | 2012-04-09 | 2012-04-09 | Ground fault detecting circuit and power conversion device using same |
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Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10585134B2 (en) | 2015-10-05 | 2020-03-10 | General Electric Company | Method and system for locating ground faults in a network of drives |
JP2021027594A (ja) * | 2019-07-31 | 2021-02-22 | 島田理化工業株式会社 | インバータユニットにおけるアース線への漏れ電流抑止回路およびインバータユニットにおけるアース線への漏れ電流抑止方法 |
JP7445894B2 (ja) | 2020-12-28 | 2024-03-08 | Anp株式会社 | 漏電検出装置 |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10439400B2 (en) * | 2013-08-21 | 2019-10-08 | General Electric Technology Gmbh | Electric protection on AC side of HVDC |
US10371758B2 (en) * | 2015-09-15 | 2019-08-06 | Lg Chem, Ltd. | Test system and method for testing a battery pack |
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Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS63265516A (ja) * | 1987-04-22 | 1988-11-02 | Hitachi Ltd | 三相交流励磁装置 |
JP2003061380A (ja) | 2001-08-10 | 2003-02-28 | Toshiba Corp | 同期機のサイリスタ起動装置 |
JP2009131048A (ja) | 2007-11-22 | 2009-06-11 | Mitsubishi Electric Corp | 複数発電機の起動システムおよび複数発電機起動用切替盤 |
JP2009526203A (ja) * | 2006-02-07 | 2009-07-16 | シーメンス アクチエンゲゼルシヤフト | 給電ケーブルの地絡検出方法および装置 |
JP2010130704A (ja) | 2008-11-25 | 2010-06-10 | Mitsubishi Electric Corp | 発電機の起動装置 |
JP2011130634A (ja) | 2009-12-21 | 2011-06-30 | Mitsubishi Electric Corp | 非接地発電機の地絡保護システム |
JP2012039711A (ja) * | 2010-08-05 | 2012-02-23 | Mitsubishi Electric Corp | 二重給電同期機の地絡検出装置 |
Family Cites Families (35)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3665495A (en) * | 1970-06-01 | 1972-05-23 | Power Systems And Controls Inc | No break power system |
JPS5041036A (ja) | 1973-08-15 | 1975-04-15 | ||
JPS5917620B2 (ja) * | 1977-02-16 | 1984-04-23 | 株式会社日立製作所 | インバ−タの保護装置 |
JPS55147930A (en) | 1979-05-08 | 1980-11-18 | Tokyo Shibaura Electric Co | Induction generator motor device |
JPS57142568A (en) * | 1981-02-27 | 1982-09-03 | Hitachi Ltd | Earth trouble detecting device for dc power transmission system |
US4475150A (en) * | 1982-04-28 | 1984-10-02 | General Electric Company | Coordinated load commutated inverter protection system |
US4618810A (en) * | 1983-02-04 | 1986-10-21 | Emerson Electric Company | Variable speed AC motor control system |
US4825327A (en) * | 1987-11-12 | 1989-04-25 | General Electric Company | Negative and zero sequence directional overcurrent unit for AC power transmission line protection |
DE3923594A1 (de) * | 1988-07-29 | 1990-02-01 | Siemens Ag | Erdschlussueberwachungseinrichtung fuer drehstromantriebe, die ueber umrichter gespeist werden |
JPH04210779A (ja) * | 1990-12-14 | 1992-07-31 | Mitsubishi Electric Corp | インバータ装置の地絡検出器及び地絡検出方法 |
US5185685A (en) * | 1991-03-28 | 1993-02-09 | Eaton Corporation | Field sensing arc detection |
JPH0984254A (ja) | 1995-09-14 | 1997-03-28 | Omron Corp | 電源装置、インバータ装置および分散型電源装置 |
US5754114A (en) * | 1996-08-26 | 1998-05-19 | Delco Electronics Corporation | Safety ground detector |
US5963406A (en) * | 1997-12-19 | 1999-10-05 | Leviton Manufacturing Co., Inc. | Arc fault detector with circuit interrupter |
DE10125910B4 (de) * | 2000-05-30 | 2007-02-01 | International Rectifier Corp., El Segundo | Verfahren und Schaltung zur Erkennung von Motor-Isolationsfehlern |
US7050279B2 (en) * | 2002-04-05 | 2006-05-23 | Smc Electrical Products, Inc. | Method and apparatus for high impedance grounding of medium voltage AC drives |
JP4061168B2 (ja) * | 2002-10-16 | 2008-03-12 | 矢崎総業株式会社 | 地絡検知装置および絶縁抵抗計測装置 |
US6977518B2 (en) * | 2002-11-11 | 2005-12-20 | Matsushita Electric Works, Ltd. | Electrical leak detecting apparatus |
US7154277B2 (en) * | 2003-08-29 | 2006-12-26 | Abb Inc. | Method and apparatus for detecting faults in AC to AC, or DC to AC power conversion equipments when the equipment is in a high impedance mode |
KR100566437B1 (ko) * | 2003-11-11 | 2006-03-31 | 엘에스산전 주식회사 | 위상천이를 이용한 인버터 고장 검출 장치 및 방법 |
US7295016B2 (en) * | 2004-06-18 | 2007-11-13 | Kokusan Denki Co., Ltd. | Electric leakage detection system |
JP4422567B2 (ja) * | 2004-06-30 | 2010-02-24 | 株式会社日立製作所 | モータ駆動装置,電動アクチュエータおよび電動パワーステアリング装置 |
JP2006081327A (ja) * | 2004-09-10 | 2006-03-23 | Mitsubishi Electric Corp | インバータの故障検出装置 |
JP4741391B2 (ja) * | 2006-03-09 | 2011-08-03 | オムロンオートモーティブエレクトロニクス株式会社 | モータ駆動回路の地絡検出装置 |
US7671675B2 (en) * | 2007-08-20 | 2010-03-02 | Rohm Co., Ltd. | Output limiting circuit, class D power amplifier and audio equipment |
US8879218B2 (en) * | 2007-12-14 | 2014-11-04 | True-Safe Technologies, Inc. | Arc fault circuit interrupter, systems, apparatus and methods of detecting and interrupting electrical faults |
EP2256506B1 (de) * | 2009-05-27 | 2019-07-03 | Bender GmbH & Co. KG | Verfahren und Vorrichtung zur Isolationsüberwachung von ungeerdeten Gleich- und Wechselspannungsnetzen |
JPWO2011040128A1 (ja) * | 2009-09-29 | 2013-02-21 | 株式会社日立製作所 | 地絡検出回路および電源装置 |
JP5401250B2 (ja) * | 2009-10-06 | 2014-01-29 | 日立オートモティブシステムズ株式会社 | 地絡検出装置 |
US8817431B2 (en) * | 2009-12-18 | 2014-08-26 | True-Safe Technologies, Inc. | System and integrated method for a parallel and series arc fault circuit interrupter |
JP4805396B2 (ja) * | 2010-03-31 | 2011-11-02 | ファナック株式会社 | モータ駆動装置 |
US8554500B2 (en) * | 2010-06-11 | 2013-10-08 | Deere & Company | System and method for ground isolation detection in a vehicle |
JP6043045B2 (ja) * | 2010-06-28 | 2016-12-14 | 株式会社東芝 | 車両用制御システム |
JP2012119244A (ja) * | 2010-12-03 | 2012-06-21 | Panasonic Corp | 燃料電池システム |
JP5993616B2 (ja) * | 2012-05-25 | 2016-09-14 | 日立オートモティブシステムズ株式会社 | 電動機の駆動制御装置 |
-
2012
- 2012-04-09 JP JP2014509916A patent/JP6126081B2/ja active Active
- 2012-04-09 EP EP12874321.8A patent/EP2837942B1/en active Active
- 2012-04-09 WO PCT/JP2012/059670 patent/WO2013153596A1/ja active Application Filing
- 2012-04-09 US US14/390,118 patent/US9606163B2/en active Active
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS63265516A (ja) * | 1987-04-22 | 1988-11-02 | Hitachi Ltd | 三相交流励磁装置 |
JP2003061380A (ja) | 2001-08-10 | 2003-02-28 | Toshiba Corp | 同期機のサイリスタ起動装置 |
JP2009526203A (ja) * | 2006-02-07 | 2009-07-16 | シーメンス アクチエンゲゼルシヤフト | 給電ケーブルの地絡検出方法および装置 |
JP2009131048A (ja) | 2007-11-22 | 2009-06-11 | Mitsubishi Electric Corp | 複数発電機の起動システムおよび複数発電機起動用切替盤 |
JP2010130704A (ja) | 2008-11-25 | 2010-06-10 | Mitsubishi Electric Corp | 発電機の起動装置 |
JP2011130634A (ja) | 2009-12-21 | 2011-06-30 | Mitsubishi Electric Corp | 非接地発電機の地絡保護システム |
JP2012039711A (ja) * | 2010-08-05 | 2012-02-23 | Mitsubishi Electric Corp | 二重給電同期機の地絡検出装置 |
Non-Patent Citations (1)
Title |
---|
"Thyristor Starter Used in Thermal Power Station", MITSUBISHI ELECTRIC TECHNICAL REPORT, vol. 67, no. 5, 1993 |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10585134B2 (en) | 2015-10-05 | 2020-03-10 | General Electric Company | Method and system for locating ground faults in a network of drives |
JP2021027594A (ja) * | 2019-07-31 | 2021-02-22 | 島田理化工業株式会社 | インバータユニットにおけるアース線への漏れ電流抑止回路およびインバータユニットにおけるアース線への漏れ電流抑止方法 |
JP7445894B2 (ja) | 2020-12-28 | 2024-03-08 | Anp株式会社 | 漏電検出装置 |
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