JP2019041500A - Inspection method of power conversion equipment - Google Patents

Abstract

To provide an inspection method of power conversion equipment that performs deterioration determination of an optical fiber, without removing the optical fiber.SOLUTION: In an inspection method of power conversion equipment having a separately excited power converter including multiple thyristors, an optical fiber, and a gate controller including a photoelectric conversion circuit for converting an optical signal transmitted from the optical fiber into an electric signal to be outputted, an AC signal generation device applies an AC voltage between main terminals of one of the multiple thyristors, an optical conversion circuit converts the AC voltage into an optical signal, the photoelectric conversion circuit converts the optical signal into an electric signal, and a waveform observation device determined whether or not the amplitude and the time width of the electrical signal satisfy a prescribed values.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to an inspection method for a power converter.

  Power converters used in power systems and the like are required to have high reliability in order to withstand long-term use. Maintenance and inspection work is indispensable for maintaining high reliability. While the maintenance and inspection work is being performed, the power conversion device is in a stopped state, and the system supplied with power by the power conversion device needs to be replaced with another system. Depending on the power supply and demand situation, it is necessary to shorten the period when it is stopped. Further, from the viewpoint of the work man-hours for inspection, it is desirable to complete the maintenance inspection work in a short time.

  For example, in the case of a separately-excited AC / DC power converter, the FV signal and the RV signal for detecting the forward operation and the reverse blocking operation of the thyristor are converted into optical signals and transmitted to the gate control device through optical fibers. Thus, the gate control device monitors the forward operation and reverse blocking operation of each thyristor, and generates an appropriate gate drive signal based on these.

  In a power converter that outputs high voltage, a large number of thyristors are connected in series, so the number of optical fibers corresponding to these thyristors is connected. There is a need to. Conventionally, all the optical fibers to be inspected are removed at the time of maintenance and inspection, and the degree of deterioration of each one is checked. Connect to the device.

  As described above, the number of optical fibers is equal to the number of thyristors × the number of signals, and an enormous amount of time is required for removal and reconnection. Further, when the optical fiber is detached, the optical fiber may be damaged. To ensure the reliability, more careful work is required, and the time required for the replacement work tends to be longer.

JP 2011-205812 A

  The embodiment provides an inspection method for a power conversion device that performs optical fiber deterioration determination without removing the optical fiber.

  An inspection method for a power conversion device according to an embodiment includes a plurality of thyristors connected in series, and an optical conversion circuit that detects a voltage between main terminals of the plurality of thyristors and converts the voltage into an optical signal. A power converter comprising: a power converter; an optical fiber that transmits the optical signal; and a gate control device that includes a photoelectric conversion circuit that converts the optical signal transmitted from the optical fiber into an electrical signal and outputs the electrical signal. It is an inspection method of a device. An AC signal generator applies an AC voltage between main terminals of the plurality of thyristors, the AC conversion circuit converts the AC voltage into an optical signal, and the photoelectric conversion circuit converts the optical signal into the optical signal. Is converted into the electric signal, and the waveform observation device determines whether the amplitude and time width of the electric signal satisfy predetermined values.

  In this embodiment, the optical converter circuit of the power converter is driven by an AC signal generator, and the optical signal transmitted through the optical fiber is converted into an electric signal by the photoelectric converter circuit of the gate controller, and the output waveform is observed. Therefore, it is possible to determine the deterioration of the optical fiber without removing the optical fiber from the device.

It is a block diagram which illustrates the inspection method of the power converter concerning a 1st embodiment. Fig.2 (a)-FIG.2 (c) are typical waveform diagrams for demonstrating the example of the criterion in the inspection method of the power converter device of 1st Embodiment. Fig.3 (a)-FIG.3 (f) are typical waveform diagrams for demonstrating the example of the criterion in the test | inspection method of the power converter device of 1st Embodiment. It is a block diagram which illustrates the test | inspection method of the power converter device which concerns on 2nd Embodiment. Fig.5 (a)-FIG.5 (d) are typical waveform diagrams for demonstrating the example of the criterion in the inspection method of the power converter device of 2nd Embodiment. FIG. 6A to FIG. 6D are schematic waveform diagrams for explaining examples of determination criteria in the inspection method for the power conversion device of the second embodiment. It is a block diagram which illustrates the inspection method of the power converter device concerning a 3rd embodiment. It is an example of the flowchart for demonstrating the test | inspection method of the power converter device of 3rd Embodiment. Fig.9 (a)-FIG.9 (c) are typical waveform diagrams for demonstrating the determination criterion in the test | inspection method of the power converter device of 3rd Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between the parts, and the like are not necessarily the same as actual ones. Further, even when the same part is represented, the dimensions and ratios may be represented differently depending on the drawings.
In the present specification and drawings, the same elements as those described above with reference to the previous drawings are denoted by the same reference numerals, and detailed description thereof is omitted as appropriate.

(First embodiment)
FIG. 1 is a block diagram illustrating an inspection method for a power conversion device according to this embodiment.
As illustrated in FIG. 1, the power conversion device 10 includes a power converter 20, optical fibers 30-1 to 30-n, and a gate control device 50. The power converter 20 and the gate control device 50 are connected by n (n is an integer of 2 or more) optical fibers 30-1 to 30-n. The power conversion device 10 controls the phase of the power converter 20 by the gate control device 50, converts AC power into DC power, and converts DC power into AC power.

  Power converter 20 includes arm A0. Arm A0 includes a plurality of thyristors TH1 to THn connected in series. In this example, the number of thyristors is n. The power converter 20 is a separately-excited converter, and drives a plurality of thyristors TH1 to THn through a gate signal optical fiber (not shown) generated by the gate control device 50.

  The arm A0 includes connection terminals 21-1a, 21-1b,..., 21-na, 21-nb connected to the anode terminal and the cathode terminal for each of the thyristors TH1 to THn. The AC signal generator 1 can be connected to a pair of connection terminals 21-1a, 21-1b,..., 21-na, 21-nb. The AC signal vs supplied by the AC signal generator 1 connected via the connection terminals 21-1a, 21-1b,..., 21-na, 21-nb is connected between the anodes and cathodes of the thyristors TH1 to THn. Can be applied. The AC signal vs is a signal having a sinusoidal AC voltage having a commercial frequency (50 Hz or 60 Hz), for example.

  The power converter 20 includes optical conversion circuits 22-1 to 22-n. The optical conversion circuits 22-1 to 22-n are connected to the thyristors TH1 to THn, respectively. More specifically, the light conversion circuit 22-1 receives the anode-cathode voltage of the thyristor TH1, converts it to an optical signal, and supplies the optical signal to the optical fiber 30-1. Other optical conversion circuits are connected and operate in the same manner.

  One end of each of the optical fibers 30-1 to 30-n is connected to the optical conversion circuits 22-1 to 22-n of the power converter 20. The other ends of the optical fibers 30-1 to 30-n are connected to the gate control device 50.

  The gate control device 50 includes photoelectric conversion circuits 52-1 to 52-n. The other ends of the optical fibers 30-1 to 30-n are connected to inputs of the photoelectric conversion circuits 52-1 to 52-n, respectively. The photoelectric conversion circuits 52-1 to 52-n convert the optical signals transmitted through the optical fibers 30-1 to 30-n, respectively, into electrical signals, perform predetermined conversion processing, and output the electrical signals. In the predetermined conversion process, for example, an arbitrary input signal is converted into a square wave voltage signal or current signal.

  The photoelectric conversion circuits 52-1 to 52-n include signal output terminals 53-1 to 53-n. The waveform observation device 2 can be connected to the signal output terminals 53-1 to 53-n. The waveform observation apparatus 2 can observe signals output from the photoelectric conversion circuits 52-1 to 52-n via the signal output terminals 53-1 to 53-n.

  Operation | movement of the test | inspection method of the power converter device of this embodiment is demonstrated. In the inspection method for the power conversion device of this embodiment, the presence or absence of deterioration of the optical fibers 30-1 to 30-n is determined by the following procedure.

  First, the AC signal generator 1 connects the AC signal vs between the anode and cathode of one of the thyristors TH-x (hereinafter, 1 ≦ x ≦ n) among the thyristors TH-1 to TH-n. Application is performed via 21-xa and 21-xb.

  The applied AC signal vs is input to the corresponding optical conversion circuit 22-x and converted into an optical signal.

  The converted optical signal is transmitted from one end of the optical fiber 30-x to the other end by the corresponding optical fiber 30-x.

  The optical signal transmitted through the optical fiber 30-x is converted into an electric signal by the photoelectric conversion circuit 52-x connected to the other end of the optical fiber 30-x, and converted into, for example, a square wave voltage signal by a predetermined conversion process. Converted.

  The converted voltage signal is output from the corresponding signal output terminal 53-x and observed by the waveform observation device 2. By setting in advance the shape of the converted signal with respect to the applied AC signal vs, it is possible to detect the deterioration of the corresponding optical fiber.

  The AC signal generator 1 is switched between the anodes and cathodes of other thyristors TH-y (hereinafter, 1 ≦ y ≦ n, y ≠ x), and the waveform observing device 2 is connected to the corresponding signal output terminal 53-y. Switch the connection to. The deterioration of the optical fiber 30-y is determined from the relationship between the applied AC signal vs and the output voltage signal via the corresponding optical conversion circuit 22-y, optical fiber 30-y, and photoelectric conversion circuit 52-y.

  The above procedure is repeated for all the optical fibers 30-1 to 30-n.

  The voltages between the anodes and cathodes of the thyristors TH-1 to TH-n are detected for both the forward voltage and the reverse blocking voltage, and are respectively transmitted to the gate controller 50 through the optical fiber. The forward voltage is detected and transmitted as an FV signal and the reverse blocking voltage as an RV signal. That is, two optical fibers for transmitting these signals are provided for each FV signal and RV signal per thyristor. In the description of the present embodiment, the FV signal and the RV signal can be handled in the same manner, and therefore, items related to the optical fiber for the FV signal will be described below. The following description can be similarly applied to an optical fiber for RV signals.

Hereinafter, an example of a criterion for determining the deterioration of an optical fiber will be described.
Fig.2 (a)-FIG.3 (f) are typical waveform diagrams for demonstrating the example of the criterion in the inspection method of the power converter device of this embodiment.
The upper diagram in FIG. 2A shows the time change of the waveform of the AC signal vs output from the AC signal generator 1. The lower diagram shows the time change of the waveform of the FV signal at the signal output terminal 53-x of the photoelectric conversion circuit 52-x of the gate control device 50. FIG. Hereinafter, the same applies to the waveform diagrams.
FIGS. 2A to 2C show waveform diagrams in the case where the optical fiber is determined to be non-defective on the basis of the determination criterion for the light amount deterioration of the optical fiber.
FIGS. 3A to 3F show waveform diagrams in the case where it is determined that there is deterioration in the determination criterion for the deterioration of the light amount of the optical fiber.

  In the example described here, the determination lower limit value vs1 and the determination upper limit value vs2 of the peak value of the AC signal vs output from the AC signal generator 1 are set in advance. In addition, a prescribed value Tspec of the pulse width for the FV signal is set in advance. When the peak value of the AC signal vs is gradually increased, the pass / fail of the optical fiber is determined based on the peak value of the AC signal vs when the pulse width of the FV signal widens to the specified value Tspec. A non-defective product is determined when the peak value of the AC signal vs falls within the range from the determination lower limit value vs1 to the determination upper limit value vs2 when the pulse width of the FV signal reaches the specified value Tspec. It is determined that there is deterioration when the peak value of the AC signal vs does not reach the determination lower limit value vs1 when the pulse width of the FV signal reaches the specified value Tspec, or when the peak value of the AC signal vs exceeds the determination upper limit. This is the case when the value vs2 is exceeded.

  As shown in FIGS. 2A to 2C, when the amplitude of the AC signal vs is increased, when the pulse width of the FV signal widens and reaches the specified value Tspec, the peak value of the AC signal vs. Is between the determination lower limit value vs1 and the determination upper limit value vs2. Therefore, in such a case, the optical fiber is determined as a good product.

  As shown in FIGS. 3A to 3C, when the amplitude of the AC signal vs is increased and the pulse width of the FV signal reaches a specified value Tspec (FIG. 3C), The peak value of the AC signal vs exceeds the determination upper limit value vs2, and it is determined that the optical fiber is deteriorated.

  FIGS. 3D to 3F show a case where the amount of light transmitted by the transmitted optical fiber is larger than a desired value. In this case as well, the optical fiber is determined to be deteriorated. As shown in FIGS. 3D to 3F, when the pulse width of the FV signal reaches the specified value Tspec (FIG. 3D), the peak value of the AC signal vs becomes the determination lower limit value vs1. If the amplitude of the AC signal vs is increased and the peak value is between the determination lower limit value vs1 and the determination upper limit value vs2, the pulse width of the FV signal exceeds the specified value Tspec. (FIG. 3 (e) and FIG. 3 (f)).

  The criteria for determining the deterioration of the optical fibers 30-1 to 30-n are not limited to those described above, and can be set appropriately. For example, the distortion rate of the output signal may be compared with a preset threshold value.

The effect of the inspection method of the power converter of this embodiment will be described.
In the inspection method for the power conversion device of this embodiment, the AC signal vs can be converted into an optical signal by the optical conversion circuits 22-1 to 22-n provided for the thyristors TH1 to THn in the power converter 20. it can. Therefore, a test light emission signal is supplied to the optical fibers 30-1 to 30-n without removing one end of each of the optical fibers 30-1 to 30-n from the optical conversion circuits 22-1 to 22-n. Can do.

  Then, using the signal output terminals 53-1 to 53-n of the photoelectric conversion circuits 52-1 to 52-n provided in the gate control device 50 so as to correspond to the optical fibers 30-1 to 30-n, Signals output from the photoelectric conversion circuits 52-1 to 52-n can be detected. Therefore, it is possible to detect the amount of light output from the optical fibers 30-1 to 30-n without removing the other ends of the optical fibers 30-1 to 30-n from the photoelectric conversion circuits 52-1 to 52-n. .

  As mentioned above, in the inspection method of the power converter of this embodiment, the presence or absence of light amount deterioration is inspected without removing any of the optical fibers 30-1 to 30-n from the power converter 20 and the gate controller 50. Can do. Therefore, it is possible to reduce the work man-hours by removing and reconnecting the optical fibers 30-1 to 30-n.

  In the present embodiment, the optical fiber is not removed from the power converter 20 and the gate control device 50 and reconnected in order to check the deterioration of the light amount of the optical fiber. Therefore, mechanical damage or the like during handling of the optical fiber does not occur, and it is not necessary to perform careful work, which can contribute to further reduction in the number of work steps.

  The optical conversion circuits 22-1 to 22-n and the photoelectric conversion circuits 52-1 to 52-n are provided for normal operation of the power conversion device 10. Therefore, the inspection method can be carried out without newly changing or correcting the equipment.

  In the above description, the optical fiber deterioration test for the FV signal has been described. However, in reality, an optical fiber for the RV signal is also provided, so the effect of reducing the work man-hours is It gets bigger.

(Second Embodiment)
FIG. 4 is a block diagram illustrating a power conversion device inspection method according to this embodiment.
As shown in FIG. 4, in the method for inspecting a power conversion device of the present embodiment, an AC signal vsa is applied to both ends of the arm A0 by the AC signal generator 101. The gate control device 150 includes a logic circuit 153. The logic circuit 153 includes an OR circuit 153a and an AND circuit 153b.

  The outputs of the photoelectric conversion circuits 52-1 to 52-n are connected to the inputs of the OR circuit 153a and the AND circuit 153b, respectively. The OR circuit 153a calculates the logical sum of the outputs of the photoelectric conversion circuits 52-1 to 52-n and outputs an FVOR signal. The AND circuit 153b calculates the logical product of the outputs of the photoelectric conversion circuits 52-1 to 52-n and outputs an FVAND signal.

  Operation | movement of the test | inspection method of the power converter device of this embodiment is demonstrated. In the inspection method for the power conversion device of this embodiment, the presence or absence of optical fiber deterioration is determined by the following procedure. However, in the case of this embodiment, whether or not there is an optical fiber deteriorated in units of arms, rather than specifying a deteriorated optical fiber among the n optical fibers 30-1 to 30-n. Determine.

  First, the AC signal generator 101 applies the AC signal vsa to both ends of the arm A0.

  The applied signal is divided by the thyristors TH-1 to TH-n, and the divided signals are input to the optical conversion circuits 22-1 to 22-n, respectively. The optical conversion circuits 22-1 to 22-n are converted into optical signals and supplied to the optical fibers 30-1 to 30-n.

  The optical fibers 30-1 to 30-n transmit an optical signal input from one end to the other end.

  The photoelectric conversion circuits 52-1 to 52-n convert the transmitted optical signal into an electric signal of a predetermined format and output it.

  The logic circuit 153 takes the logical sum and logical product of the electrical signals output from the photoelectric conversion circuits 52-1 to 52-n, and outputs them. The shape of the FVOR signal that is the logical sum and the FVAND signal that is the logical product is compared with a preset reference, and the deterioration of the optical fiber in the arm A0 unit is determined.

  When the FVAND signal is determined to be deteriorated, at least one of the optical fibers 30-1 to 30-n corresponding to the thyristors TH-1 to TH-n in the arm A0 is determined to be deteriorated. included. Therefore, it is necessary to separately perform a deterioration inspection or the like as to whether the optical fiber corresponding to any of thyristors TH-1 to TH-n of arm A0 has deteriorated.

  When the FVAND signal is determined as good, all the optical fibers 30-1 to 30-n corresponding to the thyristors TH-1 to TH-n in the arm A0 are determined as good.

  When the FVOR signal is determined to be deteriorated, all the optical fibers 30-1 to 30-n corresponding to the thyristors TH-1 to TH-n in the arm A0 are determined to be deteriorated.

  When the FVOR signal is determined to be non-defective, a non-defective product is determined for at least one of the optical fibers corresponding to the thyristors TH-1 to TH-n of the arm A0. Therefore, it is necessary to confirm whether or not the arm A0 includes a deterioration determination product together with the result of the FVAND signal. For example, when the deterioration is determined by the FVAND signal, it is necessary to separately examine the deterioration. When the non-defective product is determined by the FVAND signal, as described above, the thyristors TH-1 to TH-n in the arm A0 are non-defective.

Fig.5 (a)-FIG.6 (d) are typical waveform diagrams for demonstrating the example of the criterion in the inspection method of the power converter device of this embodiment.
Operation | movement of the test | inspection method of the power converter device of this embodiment is demonstrated using Fig.5 (a)-FIG.6 (d).
The uppermost diagram in FIG. 5A shows the time change of the waveform of the AC signal vsa output from the AC signal generator 101. The second stage diagram shows the time change of the waveform of the FVOR signal output from the OR circuit 153a. The lowermost diagram shows the time change of the waveform of the FVAND signal output from the AND circuit 153b. The same applies to the waveform diagrams of FIGS. 5B to 6D.

  FIGS. 5A to 5D show the case where the amplitude of the AC signal vsa is increased in the order of FIGS. 5A to 5D in the case where the light quantity of the optical fiber is determined as non-defective. The waveforms of the FVOR signal and the FVAND signal are shown. FIG. 5A shows a case where the AC signal vsa has reached the determination lower limit value vsa1. FIG. 5B shows that the pulse width of the FVOR signal has reached the specified value Tspec after the AC signal vsa has exceeded the determination lower limit value vsa1. In this example, the pulse width of the FVAND signal is narrower than the pulse width of the FVOR signal.

  The FVOR signal is a logical sum of square wave signals output from the photoelectric conversion circuits 52-1 to 52-n, respectively. The signals output from the photoelectric conversion circuits 52-1 to 52-n are optical signals that have propagated through the optical fibers 30-1 to 30-n. These optical signals are supplied by the optical conversion circuits 22-1 to 22-n at one end of the optical fibers 30-1 to 30-n. Assuming that the impedances of the thyristors TH-1 to TH-n are all equal, a voltage of vsa / n is applied to both ends of each thyristor.

  As shown in FIG. 5B, the OR circuit 153a outputs the output having the widest pulse width among the outputs of the photoelectric conversion circuits 52-1 to 52-n. In other words, what is determined by the FVOR signal in FIG. 5B is that the light amount deterioration of the optical fibers corresponding to some thyristors in the arm A0 is at a non-defective level.

  As shown in FIG. 5C and FIG. 5D, when the peak value of the AC signal vsa is further increased, the pulse width of the FVAND signal reaches the specified value Tspec. The AND circuit 153b outputs the output having the narrowest pulse width among the outputs of the photoelectric conversion circuits 52-1 to 52-n. That is, in the states of FIG. 5C and FIG. 5D, it is shown that even when the amount of light transmitted by the optical fiber is the smallest, the amount of light exceeding the specified value can be transmitted.

  FIGS. 6A to 6D show a case where the transmission of the light amount of any one or more of the n optical fibers is deteriorated. As shown in FIGS. 6A to 6C, the FVOR signal reaches the specified value Tspec when the AC signal vsa is in the range from the determination lower limit value vsa1 to the determination upper limit value vsa2. This indicates that the deterioration of the light amount of any one or more of the n optical fibers is at a non-defective level.

  However, as shown in FIGS. 6C and 6D, the FVAND signal does not reach the specified value Tspec even when the AC signal vsa reaches the determination upper limit value vsa2, and further the peak value of the AC signal. The specified value Tspec is reached only when the value is increased. That is, this indicates that one or more of the n optical fibers has a level of deterioration in light quantity.

  The logic circuit 153 may be realized by hardware using an OR gate and an AND gate, or may be ORed and ANDed as program steps.

The effect of the inspection method of the power converter of this embodiment will be described.
In the present embodiment, since the gate control device 50 includes the logic circuit 153, there is a case where a large number of optical fibers 30-1 to 30-n are not deteriorated with respect to the presence or absence of light amount deterioration. It can be detected quickly.

  If the optical fibers 30-1 to 30-n include ones with a large deterioration in the amount of light, all the n optical fibers may be inspected. In order to inspect all the optical fibers, the case of the first embodiment described above may be applied, or another method may be used.

  The power conversion apparatus may be provided with a large number of arms A0, and when inspecting the optical fibers of a large number of power conversion apparatuses, the inspection is performed for each optical fiber corresponding to each thyristor in the arm. Doing so reduces the efficiency of the inspection. In the inspection method for the power conversion device of this embodiment, for example, an inspection is performed for each arm A0, and it is possible to determine whether or not the corresponding optical fiber has deteriorated in units of the arm A0. Thereafter, a detailed inspection is performed on the arm A0 including the optical fiber determined to have a large deterioration, thereby guaranteeing the inspection efficiency and the reliability of the inspection.

  When the logical sum and logical product of the logic circuit 153 are executed as program steps, the logic circuit 153 can be easily implemented, so that the efficiency of the inspection can be realized using the current apparatus.

  In the embodiment described above, the AC signal is applied in units of the arm A0. However, the unit of application of the AC signal is not limited to the unit of the arm A0. The thyristors TH-1 to TH-n in the arm A0 may be grouped into groups of several, and an AC signal may be sequentially applied to each group unit to determine the deterioration of the corresponding optical fiber.

(Third embodiment)
FIG. 7 is a block diagram illustrating an inspection method for the power conversion device according to this embodiment.
As shown in FIG. 7, in the power conversion device inspection method according to the present embodiment, the power conversion device has a gate control device 250 that is different from those in the other embodiments described above. The gate control device 250 includes a logic circuit 253. The logic circuit 253 includes OR circuits 253-1a to 253-ma and AND circuits 253-1b to 253-mb.

  In the present embodiment, the arm A0 includes n thyristors TH-1 to TH-n connected in series. The arm A0 includes a group of m thyristors (m is an integer of 2 or more). For example, this group of thyristors is a thyristor module. That is, the arm A0 includes m thyristor modules M-1 to M-m connected in series, and each thyristor module includes k (= n / m) thyristors.

  In the present embodiment, an OR circuit and an AND circuit are connected to each of the thyristor modules M-1 to M-m. That is, the OR circuit 253-1a and the AND circuit 253-1b are connected to the thyristor module M-1, and the OR circuit 253-ma and the AND circuit 253-mb are connected to the thyristor module M-m.

  The AC signal generator 101 outputs an AC signal vsa. The voltage applied to both ends of the thyristor modules M-1 to M-m is substantially set according to the number of thyristors included in each module. For example, when the number of thyristors included in all the thyristor modules M-1 to M-m is the same, the voltages applied to both ends of the thyristor modules M-1 to M-m are equal. For example, the applied voltage of the thyristor module is vsa / m. In the following description, it is assumed that an equal voltage is applied to each thyristor module.

  The AC signal generator 101 is connected to both ends of the arm A0. The AC signal generator 101 supplies the voltage signal vsa to the arm A0. A voltage vsm is applied to each of the thyristor modules M-1 to Mm. For example, according to the voltage applied to both ends of each thyristor of the thyristor module M-1, the corresponding light conversion circuit emits light having a light amount corresponding to the applied voltage.

  The corresponding optical fiber transmits the output light of the light conversion circuit to the photoelectric conversion circuit connected to the other end. The photoelectric conversion circuit outputs a pulse signal corresponding to the amount of received light.

  The pulse signal output from the photoelectric conversion circuit is input to the OR circuit and the AND circuit, respectively. The OR circuit outputs a pulse signal having the widest pulse width among the input pulse signals. The AND circuit outputs a pulse signal having the narrowest pulse width among the input pulse signals.

FIG. 8 is a flowchart illustrating the inspection method for the power conversion device according to this embodiment.
Below, after extracting the thyristor module by which the optical fiber degradation determination was carried out using the test | inspection method of this embodiment, the degradation determination of the optical fiber corresponding to all the thyristors is performed about the thyristor module.

  As shown in FIG. 8, in this embodiment, in step S01, the light amount deterioration of the optical fiber corresponding to each thyristor module of the arm A0 is determined, and the optical fiber group corresponding to the thyristor module determined to be deteriorated is extracted. To do.

  More specifically, in step S11, the AC signal generator 101 applies the AC signal vsa to both ends of the arm A0. The peak value of the output AC signal is changed in the range from the minimum value to the maximum value.

  In step S12, the optical conversion circuit converts the alternating current signal into an optical signal and supplies the optical signal to the corresponding optical fiber.

  In step S13, the optical signal is transmitted from one end to the other end by the optical fiber.

  In step S14, the transmitted optical signal is converted into an electric signal of a predetermined format by the photoelectric conversion circuit.

  In step S15, the logical circuit 253 takes the logical sum and logical product of all the converted electrical signals and outputs them. The waveform observation device 2 determines the deterioration of the optical fiber corresponding to the corresponding thyristor module based on the output logical sum and logical product.

  Next, in step S02, the AC signal vs is applied to each of the thyristors constituting the thyristor module that has been determined to be deteriorated and extracted, and deterioration of the corresponding optical fiber is determined.

  More specifically, in step S21, the AC signal generator 1 sequentially applies the AC signal vs to both ends of each thyristor.

  In step S22, the applied AC signal vs is converted into an optical signal by the corresponding optical conversion circuit.

  In step S23, the converted optical signal is transmitted from one end to the other end by the corresponding optical fiber.

  In step S24, the optical signal transmitted by the photoelectric conversion circuit is converted into an electric signal, and is converted into, for example, a square wave voltage signal by a predetermined conversion process.

  In step S25, the waveform observation apparatus 2 observes the waveform of the converted voltage signal at the corresponding signal output terminal. By setting in advance the shape of the converted signal with respect to the applied AC signal vs, it is possible to detect the deterioration of the corresponding optical fiber.

  In this manner, it is determined whether or not the transmission of the light amount has deteriorated for each optical fiber.

  In the above description, the arm A0 is divided into several thyristor modules, and light amount deterioration is determined for each thyristor module. For example, when the number of thyristors included in the arm A0 is small, the light amount deterioration may be determined without dividing the arm A0. In that case, it can be realized by replacing the above-described step S01 with the case of the second embodiment.

Fig.9 (a)-FIG.9 (c) are typical waveform diagrams for demonstrating the determination criterion in the test | inspection method of the power converter device of this embodiment.
9 (a) to 9 (c) show the time change of the waveform of the test voltage vsm applied to both ends of each thyristor. The second stage diagram shows the time change of the waveform of the FVAND signal output from the AND circuit 253-1b corresponding to the thyristor module M-1. The third diagram shows the time change of the waveform of the FVAND signal output from the AND circuit 253-2b corresponding to the thyristor module M-2. The lowermost diagram shows the time change of the waveform of the FVAND signal output from the AND circuit 253-mb corresponding to the thyristor module M-m.

  As shown in FIGS. 9A to 9C, some of the thyristor modules (in this example, at least thyristor modules M-1 and M-2) have a minimum voltage vsm applied to both ends. In the range from vsm1 to the maximum value vsm2, the pulse width of the FVAND signal reaches the specified value Tspec. In this example, among the thyristor modules M-m, the pulse width of the FVAND signal does not reach the specified value Tspec even when the inspection voltage vsm reaches the maximum value vsm2. That is, the thyristor module M-m includes a thyristor corresponding to the optical fiber in which the light amount is deteriorated.

  In FIGS. 9A to 9C, the FVOR signal is not shown, but if the pulse width of the FVOR signal does not reach the specified value Tspec, the thyristor included in the thyristor module is used. It is determined that the amount of light has deteriorated for all of the corresponding optical fibers.

The effect of the inspection method of the power converter of this embodiment will be described.
In the present embodiment, one arm A0 is divided into a plurality of thyristor modules, and a logic circuit 253 including an OR circuit and an AND circuit corresponding to the divided thyristor modules is included. Therefore, it is possible to determine the presence or absence of deterioration in the light amount transmission of the optical fiber corresponding to each divided thyristor module.

  In the case of a separately-excited power converter used for high-voltage direct current power transmission or the like, a large number of thyristors are connected in series to the arm in order to support high-voltage input / output. Such a power conversion device has a multi-phase arm, and includes, for example, a 6-phase arm, a 12-phase arm, and the like. In such a case, when the inspection is performed for each arm and the deterioration is determined, an individual check of a large number of optical fibers is required to identify the optical fiber determined to be deteriorated.

  In the inspection method for the power conversion device of this embodiment, it is possible to efficiently detect the deterioration of the corresponding optical fiber in the thyristor module by appropriately setting the number of the divided thyristor modules in series. For example, by performing an individual check for each thyristor module whose deterioration is detected, it is possible to reliably identify the deteriorated optical fiber.

  In the third embodiment, after the quality determination of the thyristor modules M-1 to M-m in the arm A0, the deterioration determination is performed for each optical fiber on the thyristor module in which the deterioration is detected. As described above, since a power converter having a large power capacity has multi-phase arms, deterioration determination of optical fibers in units of arms in the power converter may be performed in advance. Specifically, before the pass / fail judgment of the thyristor module in each arm, the pass / fail judgment of the optical fiber of each arm is performed (corresponding to the second embodiment), and the arm including the optical fiber deteriorated in advance is extracted. . For the arm, the deterioration determination of the optical fiber for each thyristor module may be performed, and then the deterioration determination for each optical fiber may be performed.

  According to the embodiment described above, it is possible to realize an inspection method for a power conversion device that performs optical fiber deterioration determination without removing the optical fiber.

  As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and the equivalents thereof. Further, the above-described embodiments can be implemented in combination with each other.

  DESCRIPTION OF SYMBOLS 1,101 AC signal generator, 2 Waveform observation apparatus, 10 Power converter, 20 Power converter, 22-1 to 22-n Optical conversion circuit, 30-1 to 30-n Optical fiber, 50 Gate controller, 52 -1 to 52-n photoelectric conversion circuit, 53-1 to 53-n signal output terminal, 153,253 logic circuit

Claims (4)

A power converter comprising: a plurality of thyristors connected in series; and an optical conversion circuit that detects a voltage between main terminals of each of the plurality of thyristors and converts the voltage into an optical signal;
An optical fiber for transmitting the optical signal;
A gate control device including a photoelectric conversion circuit that converts an optical signal transmitted from the optical fiber into an electrical signal and outputs the electrical signal;
An inspection method for a power converter having
By applying an AC voltage between one main terminal of the plurality of thyristors by an AC signal generator,
The AC conversion circuit converts the AC voltage into an optical signal,
The photoelectric conversion circuit converts the optical signal into the electrical signal,
A method for inspecting a power converter, wherein the waveform observation device determines whether or not the amplitude and time width of the electrical signal satisfy predetermined values, respectively. A power converter comprising: a plurality of thyristors connected in series; and an optical conversion circuit that detects a voltage between main terminals of each of the plurality of thyristors and converts the voltage into an optical signal corresponding to each of the plurality of thyristors. When,
An optical fiber for transmitting the optical signal;
A gate control device comprising: a photoelectric conversion circuit that converts an optical signal transmitted from the optical fiber into an electrical signal and outputs the electrical signal; and a logic circuit that performs a logical operation of the electrical signal corresponding to each of the plurality of thyristors; ,
An inspection method for a power converter having
By applying an AC voltage to both ends of the series connection body of the plurality of thyristors by an AC signal generator,
The AC conversion circuit converts the AC voltage into an optical signal,
The photoelectric conversion circuit converts the optical signal into the electrical signal,
An inspection method for a power conversion apparatus, wherein a waveform observation apparatus determines whether or not an amplitude and a time width of an output signal of the logic circuit satisfy predetermined values. The photoelectric conversion circuit includes a square wave shaping circuit that converts the input optical signal into a square wave according to the amplitude and time width of the optical signal,
The method of testing a power converter according to claim 2, wherein the logic circuit outputs a logical sum and a logical product of square wave signals output from the square wave shaping circuit. The plurality of thyristors includes two or more groups,
The logic circuit is:
For one of the two or more groups,
Performing a logical operation of the electrical signal corresponding to each thyristor included in the one group among the plurality of thyristors;
For the other one of the groups,
4. The method for inspecting a power conversion device according to claim 2, wherein logical operation of the electrical signal corresponding to each thyristor included in the other one group among the plurality of thyristors is performed. 5.

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