JP2007166708A - Power converter, suppressing method for surge voltage and wind power system therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress, using a reactor with small dimension and weight, an adverse effect of a surge voltage or rate of change dV/dt in voltage with time on an AC generator because inductance or electrostatic capacity is large when a voltage type PWW inverter is connected with the AC generator or a generator through a relative long cable. <P>SOLUTION: The reactor 21 is connected with a cable 3 connecting an output terminal of the power converter 1 with the generator or a motor 4. Next, a serial circuit of a resistor 22 and a capacitor 23 is connected with the reactor 21 in parallel. Furthermore, a capacitor 24 is connected with between respective phase lines of the cable 3 between the serial circuit and the generator or the motor 4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a power converter, its surge voltage suppressing method, and wind power generation system.

  Patent Document 1 discloses a surge voltage suppression technique when a voltage type PWW inverter is connected to an AC motor via a relatively long cable. That is, in the cable connecting the voltage type PWM inverter and the AC motor, a reactor is connected in series, a resistor is connected in parallel with the reactor, and a parallel body of these reactor and resistor forms a surge voltage suppression circuit. is doing. The cable itself has an inductance and a capacitance, and constitutes a resonance circuit. When the length of the cable is relatively long, for example, several tens of meters or more, the inductance value and the capacitance values Ll and Cl become large. Therefore, the surge voltage and the time change rate dV / dt of the voltage are AC. Adversely affects the motor.

  Here, the adverse effect of the surge voltage and the voltage change rate dV / dt on the AC motor will be described.

  From the output terminal of the voltage type PWM inverter, a pulsed voltage as shown in FIG. When there is no surge voltage suppression circuit and the time change rate dV / dt of the pulse voltage is large, the voltage applied to the terminal of the AC motor by the resonance circuit in the cable includes a surge voltage. This surge voltage may increase to twice the pulse voltage depending on the conditions of the resonance circuit. Application of this high surge voltage breaks the insulation of the AC motor and shortens its life.

  Moreover, the stator of an AC motor is generally constituted by windings. Between the windings and between the windings and the casing of the AC motor, an insulator is used to ensure insulation. When the time change rate dV / dt of the voltage applied to the stator winding is large, stray capacitance exists between the winding and the casing, and thus current flows from the winding to the casing through the insulator. . At this time, the current i flowing through the insulating portion is expressed by the equation (1), where Cz is the stray capacitance between the winding and the casing.

i = Cz · dV / dt (1)
Even if the stray capacitance Cz is small, the current i flowing is large if dV / dt is large. Due to the current flowing through the insulating portion, the insulating performance of the insulating portion deteriorates. For this reason, the life of the AC motor is shortened.

  As a countermeasure, in Patent Document 1, a surge voltage suppression circuit is configured by connecting a reactor to an output terminal of a power converter and connecting a resistor in parallel with the reactor. With this surge voltage suppression circuit, the surge voltage at the terminal of the AC motor and the time rate of change dV / dt of the voltage can be lowered.

JP-A-11-262247 (Overall)

  Among the surge voltage suppression circuits, the reactor has the largest weight and is desired to be lighter. However, the inductance value of the reactor is the inductance of the cable, the stray capacitance, and the time change rate dV / dt of the target voltage. It depends on the value. For this reason, a large thing was required as the reactor.

  The objective of this invention is making the reactor for surge voltage suppression small in the power converter device provided with the power converter connected to a generator or an electric motor via a comparatively long cable.

  In a preferred embodiment of the present invention, in a power conversion apparatus in which a power converter is connected to a generator or a motor by a plurality of cables, a reactor is inserted into a cable connecting the power converter to the generator or the motor. The reactor is characterized in that a series body of a resistor and a capacitor is connected in parallel.

  Further, in a preferred embodiment of the present invention, a capacitor is connected between each phase line of the cable connecting the reactor and the parallel circuit of the resistor and the capacitor in series and the generator or the motor. It is characterized by.

  In another embodiment of the present invention, in a cable connecting the power converter and the generator or motor, a parallel body of a reactor and a resistor is connected, and the parallel body and the generator or motor are connected. A capacitor is connected between the phase wires of the cable to be connected.

  According to a preferred embodiment of the present invention, by connecting a series circuit composed of a resistor and a capacitor in parallel with the reactor, the surge voltage generated at the terminal of the generator or the motor can be suppressed, so that the inductance of the reactor Can be reduced.

  Other objects and features of the present invention will be made clear in the embodiments described below.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  A first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a main circuit configuration diagram of a power conversion device including a power converter connected to an AC generator or a motor via a relatively long cable according to Embodiment 1 of the present invention. In the figure, a power converter 1 is connected to a generator or an electric motor 4 by a cable 3 via a surge voltage suppression circuit (filter) 2A. Examples of the generator or the motor 4 include an AC excitation synchronous generator, a permanent magnet generator, an induction generator, and a synchronous generator.

  The power converter 1 includes a converter 11 that converts alternating current into direct current, a direct current capacitor 12, and a PWM inverter 13 that uses a semiconductor switching element.

  2 and 3 are specific main circuit configuration diagrams of the converter 11 in the power converter 1 according to the first embodiment of the present invention. An example of the converter 11 is a PWM converter 11A using a semiconductor switching element as shown in FIG. When the generator or the motor 4 is an electric motor, a diode rectifier 11B may be used as shown in FIG.

  The cable 3 that connects the power converter 1 and the generator or the motor 4 has an inductance component 31 and a capacitance component 32 between the lines or between the ground. This inductance and capacitance are represented as Ll and Cl, respectively. The inductance Ll and capacitance Cl of the cable 3 form a resonance circuit. When there is no surge voltage suppression circuit 2A and a pulse voltage is applied from the power converter 1, a resonance phenomenon occurs in the resonance circuit, and the output of the power converter 1 is output to the terminal of the generator or the motor 4 at the maximum. A surge voltage having an amplitude twice that of the pulsed voltage is applied. This surge voltage breaks the insulation of the generator or motor 4 and shortens the life of the generator or motor 4.

  In addition, when the time change rate dV / dt of the voltage applied from the power converter 1 is large, a current flows through the insulator part through the stray capacitance between the windings or between the winding part and the housing. become. This current deteriorates the insulator, leading to dielectric breakdown.

  In order to prevent the dielectric breakdown of the generator or motor 4 as described above, a surge voltage suppression circuit 2 </ b> A is connected between the generator or motor 4 and the power converter 1.

  The surge voltage suppression circuit 2A connects the reactor 21 (inductance Lf) between the output side of the power converter 1 and the generator or the motor 4, and includes a resistor 22 (resistance value Rf) and a capacitor 23 (capacitance Cf). A serial body is configured to be connected in parallel to the reactor 21. Due to the effect of the surge voltage suppression circuit 2A, the inductance Lf of the reactor 21 can be made sufficiently smaller than the conventional one while exhibiting the surge voltage suppression effect and the voltage / time change rate dV / dt suppression effect. Below, it demonstrates using a concrete numerical value.

  Assuming that the DC voltage of the power converter 1 is 3000 V, a pulse voltage having an amplitude of 3000 V is applied to the output terminal of the power converter 1. The cable 3 is a CVT cable (Triplex type cross-linked polyethylene insulated vinyl sheath cable) for 6.6 kV. The inductance Ll per unit length of the CVT cable and the electrostatic capacitance Cl per unit length are 0.32 [mH / km] and 0.7 [uF / km], respectively. The length of the cable 3 is 100 m. The inductance Ll and the capacitance Cl of the cable 3 are Ll = 0.032 [mH] and Cl = 0.07 [μF], respectively.

  When the inductance Lf, resistance value Rf, and capacitor capacitance Cf of the surge voltage suppression circuit 2A are selected to appropriate values, for example, Lf = 0.32 [mH], Rf = 35 [Ω], Cf = 0.7 [μF]. The surge can be suppressed without changing the voltage time change rate dV / dt.

  FIG. 4 is a simulation waveform diagram of the voltage at the end of the generator or motor 4 in Embodiment 1 of the present invention. That is, the result of obtaining the waveform of the voltage at the generator or the motor 4 end when the pulse voltage is output from the power converter 1 by using the electric circuit simulator is shown. As can be seen from FIG. 4, it can be seen that the peak value of the surge voltage is lower when the capacitor 23 is added than when the capacitor 23 is not provided. By reducing the surge voltage, the inductance Lf of the surge voltage suppression circuit 2A can be lowered.

  FIG. 5 is a second simulation waveform diagram of the voltage at the end of the generator or motor 4 according to the first embodiment of the present invention. This is a result of calculating a voltage waveform when the inductance of the surge voltage suppression circuit 2A is lowered to Lf = 0.25 [mH] using an electric circuit simulator. As can be seen from FIG. 5, by adding the capacitor 23, the inductance Lf can be reduced while the suppression effect of the surge voltage and the voltage-time change rate dV / dt remains the same. Under this circuit condition, the inductance Lf can be reduced to 0.25 / 0.32 × 100≈78%.

  According to the first embodiment, the inductance Lf can be reduced to 78% of the conventional value, and its volume and weight can be reduced to about 83%. Further, when the reactor Lf having the same inductance is employed, the surge voltage can be further reduced, so that the insulation deterioration of the generator or the motor 4 can be prevented.

  Next, a second embodiment of the present invention will be described with reference to FIGS.

  FIG. 6 is a main circuit configuration diagram of the power conversion device according to the second embodiment of the present invention. In FIG. 6, the same function parts as those in FIG. The difference between the second embodiment and the first embodiment is the configuration of the surge voltage suppression circuit 2B. In the surge voltage suppression circuit 2B according to the second embodiment, the reactor 21 is connected in series to the output terminal of the power converter 1, and the resistor 22 (resistance value Rf) is connected in parallel with the reactor 21 (inductance Lf). . Further, a capacitor 24 (capacitance C) is connected between each phase wire of the cable between the parallel body of the reactor 21 and the resistor 22 and the generator or the motor 4. Capacitor 24 is a three-phase capacitor, and its neutral point may be isolated from other parts or connected to the ground of the power converter.

  Compared with the first embodiment, the characteristic part of the second embodiment is the line capacitor 24 (capacitance C) of the surge voltage suppression circuit 2B. Due to this effect, the voltage applied to the end of the generator or the motor 4 is reduced. Time change rate dV / dt is further suppressed. Below, it demonstrates using a concrete numerical value.

  As in the first embodiment, the impedance of the cable 3 is Ll = 0.032 [mH] and Cl = 0.07 [μF]. The setting of the power converter 1 is the same as that of the first embodiment, and it is assumed that a pulse voltage having an amplitude of 3000 V is applied to the output terminal of the power converter 1. In order to suppress the surge voltage and the voltage time change rate dV / dt, the constants Rf, Lf, and C of the surge voltage suppression circuit 2B are set to appropriate values.

  FIG. 7 is a simulation waveform diagram of the voltage at the end of the generator or motor 4 in Embodiment 2 of the present invention. By using the electric circuit simulator, the waveform of the line voltage at the end of the generator or the motor 4 when the pulse voltage was output from the power converter 1 was obtained. The setting conditions are an inductance Lf = 0.32 [mH], a resistance value Rf = 9 [Ω], and a capacitance C = 3.5 [μF]. For comparison, a simulation was performed with an inductance Lf = 0.32 [mH] and a resistance value Rf = 35 [Ω] under the condition that the capacitor 24 (capacitance C) was not provided. The reason why the resistance values are different under the two conditions is that an appropriate resistance value under each condition is selected.

  As can be seen from FIG. 7, the time change rate dV / dt of the voltage decreases when the capacitor 24 (capacitance C) is connected.

  If this embodiment is applied, the time change rate dV / dt of the voltage can be adjusted to a value necessary for insulation protection of the generator or the motor 4.

  Next, a third embodiment of the present invention will be described with reference to FIGS.

  FIG. 8 is a main circuit configuration diagram of the power conversion device according to the third embodiment of the present invention. In FIG. 8, the same function parts as those in FIG. The difference between the third embodiment and the first embodiment is the configuration of the surge voltage suppression circuit 2C. In the surge voltage suppression circuit 2C according to the third embodiment, a reactor 21 is connected to the output terminal of the power converter 1, and a resistor 22 (resistance value Rf) and a capacitor 23 (capacitance Cf) are connected in parallel with the reactor 21 (inductance Lf). ) Are connected in parallel. Further, a capacitor 24 (capacitance C) is connected between the phase wires of the cable connecting the reactor 21 and the generator or the motor 4. The capacitor 24 is a three-phase capacitor, and its neutral point may be isolated from other parts or connected to the ground of the power converter 1. The characteristic part of the third embodiment compared to the second embodiment is a capacitor 23 (capacitance Cf) in the surge voltage suppression circuit 2C, and the surge voltage applied to the generator or the motor 4 end due to the effect thereof. Is further suppressed. Below, it demonstrates using a concrete numerical value.

  The impedance of the cable 3 is L1 = 0.032 [mH] and Cl = 0.07 [μF] as in the first and second embodiments. The setting of the power converter 1 is the same as in the first and second embodiments, and it is assumed that a pulsed voltage having an amplitude of 3000 V between lines is applied to the output terminal of the power converter 1. In order to suppress the surge voltage and the voltage change rate dV / dt, the constants Lf, Rf, Cf, and C of the surge voltage suppression circuit 2C are set to appropriate values.

  FIG. 9 is a simulation waveform diagram of the voltage at the end of the generator or motor 4 in the third embodiment of the present invention. By using the electric circuit simulator, the waveform of the line voltage at the end of the generator or the motor 4 when the pulse voltage was output from the power converter 1 was obtained. The setting conditions are an inductance Lf = 0.32 [mH], a resistance value Rf = 9 [Ω], a capacitance Cf = 6 [μF], and C = 0.7 [μF]. For comparison, the simulation was also performed under the condition where there is no capacitor 23 (capacitance Cf), that is, Lf = 0.32 [mH], Rf = 9 [Ω], and C = 0.7 [μF]. As is apparent from FIG. 9, when the capacitor 23 (Cf) is connected, the time change rate dV / dt of the voltage remains substantially the same, and the peak of the surge voltage is reduced.

  By reducing the surge voltage, the inductance Lf of the surge voltage suppression circuit 2C can be lowered.

  FIG. 10 shows a calculation result of a voltage waveform when the inductance of the surge voltage suppression circuit 2C is lowered to Lf = 0.25 [mH] using an electric circuit simulator. As can be seen from FIG. 10, by adding the capacitor 23 (capacitance Cf), the inductance Lf can be reduced while the effect of suppressing the surge voltage and the voltage temporal change rate dV / dt is equal. Under this circuit condition, the inductance Lf can be reduced to 0.25 / 0.32 × 100≈78%.

  If this embodiment is used, the inductance Lf can be reduced to 78% of the conventional value, and its volume and weight can be reduced to about 83%. Further, when the reactor Lf having the same inductance is employed, the surge voltage can be further reduced, so that the insulation deterioration of the generator or the motor 4 can be prevented.

  Next, a fourth embodiment of the present invention will be described with reference to FIGS.

  FIG. 11: is a main circuit block diagram of the power converter device by Example 4 of this invention. In FIG. 11, the same function parts as those in FIG. The fourth embodiment is different from the first embodiment in that the surge voltage suppression circuit is applied to the wind power generation system.

  First, an outline of the wind power generation system will be described with reference to FIG.

  FIG. 12 is a schematic configuration diagram of a preferred wind power generation system to which the present invention is applied. The wind power generation system receives wind by the blade 5 and converts wind energy into rotational energy. The rotational energy is transmitted to the gear 8 through the rotor shaft 7. In the gear 8, the rotational speed of the blade 5 is converted into a rotational speed suitable for the generator 6. The generator 6 converts the rotational energy transmitted through the rotor shaft 7 into three-phase alternating current electric energy. This electric energy is transmitted to the power converter 1 through the cable 3 and via the surge voltage suppression circuit 2A. The power converter 1 supplies the electric energy from the generator 6 to the power system 9 and controls the power and rotation speed of the generator 6. As described in the first embodiment, the power converter 1 includes the converter 11, the DC capacitor 12, the PWM inverter 13, and the like.

  The generator 6 is housed in a container located at the top of the wind power generation system called the nacelle 100. The nacelle 100 is installed on the tower 110 so as to be rotatable in the horizontal direction. On the other hand, the power converter 1 may be installed on the ground portion in the tower 110 from the viewpoint of reducing the weight and size of the nacelle 100 portion.

  For example, in a wind power generation system with a power generation capacity of 2 MW to 3 MW class, the height of the tower 110 may exceed 100 m. As the power generation capacity increases, the tower 110 becomes even higher. For this reason, the power converter 1 and the generator 6 are connected by the cable 3 of about 100 m. As the cable 3 becomes longer, the values of the inductance 31 and the capacitance 32 of the cable 3 also increase. The inductance 31 and the capacitance 32 of this cable constitute an LC resonance circuit. When a pulsed voltage is output from the power converter 1, reflection occurs in this LC circuit, and a surge voltage having an amplitude twice as large as the output voltage of the power converter 1 at the input terminal of the generator 6. Will be applied. This high surge voltage causes the generator 6 to break insulation and shorten its life. For this reason, a circuit configuration and a function for suppressing the surge voltage are particularly important.

  In the present embodiment, the surge voltage suppression circuit 2A is connected to the output terminal of the power converter 1 in the same manner as in the first embodiment (FIG. 1) in order to suppress the above-described surge voltage and the voltage change rate dV / dt. . Specific numerical examples are the same as those shown in the description of FIGS.

  By applying this embodiment, the value Lf of the reactor 21 constituting the surge voltage suppression circuit can be reduced. Moreover, since the surge voltage at the input terminal of the generator 6 and the time change rate dV / dt of the voltage can be suppressed, the insulation deterioration of the generator 6 in the wind power generation system can be prevented.

  Next, a fifth embodiment of the present invention will be described with reference to FIG.

  FIG. 13: is a main circuit block diagram of the power converter device by Example 5 of this invention. In FIG. 13, the same function parts as those in FIG. The difference between the fifth embodiment and the second embodiment shown in FIG. 6 is that the fifth embodiment is applied to a wind power generator system.

  Specific configurations, operations, and effects are the same as those described with reference to FIGS.

  If this embodiment is applied, the time change rate dV / dt of the voltage can be designed arbitrarily, and the time change rate dV / dt of the voltage applied to the terminal of the generator 6 can be reduced, so that the insulation deterioration of the generator 6 is prevented. it can.

  Next, Embodiment 6 of the present invention will be described with reference to FIG.

  FIG. 14: is a main circuit block diagram of the power converter device by Example 6 of this invention. In FIG. 14, the same reference numerals are given to the same functional units as those in FIG. The difference between the sixth embodiment and the third embodiment shown in FIG. 8 is that the sixth embodiment is applied to a wind power generator system.

  Specific configurations, operations, and effects are the same as those described with reference to FIGS.

  If this embodiment is used, the inductance Lf can be further reduced. Moreover, since the surge voltage can be suppressed, the insulation deterioration of the generator 6 can be prevented.

  Next, Embodiment 7 of the present invention will be described with reference to FIGS. 15, 16, and 17. FIG. 15 to 17 are configuration diagrams of the surge voltage suppression circuit in the power conversion device according to the seventh embodiment of the present invention. The same reference numerals are given to the same functional units as those in FIG. The difference between the seventh embodiment and the first embodiment shown in FIGS. 1, 6 and 8 is that a plurality of intermediate taps are provided in the reactor 21 in each of the surge voltage suppression circuits 2D, 2E, and 2F.

  In FIG. 15, a series body of a resistor 22 and a capacitor 23 is connected in parallel between one of the plurality of intermediate taps of the reactor 21 and one of the terminals of the reactor 21. In addition, FIG. 16 shows that a resistor 22 is connected in parallel between one of the plurality of intermediate taps of the reactor 21 and one of the terminals of the reactor 21, and the reactor 21 and the generator or the motor 4 are connected. A capacitor 24 is connected between each phase wire of the cable 3 to be connected. Further, in FIG. 17, a series body of a resistor 22 and a capacitor 23 is connected between one of the plurality of intermediate taps of the reactor 21 and one of the terminals of the reactor 21, and the reactor 21 and the generator or A capacitor 24 is connected between each phase wire of the cable 3 connecting the electric motor 4.

  For example, it is assumed that a target to which these surge voltage suppression circuits 2D, 2E, and 2F are applied is a wind power generation system. When the power converter 1 to which the surge voltage suppression circuit is applied is installed in a wind power generation system of a plurality of manufacturers, the height of the tower differs for each manufacturer. When the height of the tower is different, the length of the cable 3 is different, and the impedance of the cable 3 is also different. Moreover, even if it is the same manufacturer, if the kind of the cable 3 to be used differs, the impedance of the cable 3 will also change. For this reason, the constant values Lf, Rf, Cf, and C of the surge voltage suppression circuit must be set each time so as to match each impedance. If the reactor (inductance Lf) 21 has a plurality of intermediate taps, even if the impedance of the cable 3 is different, by selecting the tap to be connected, the surge voltage can be suppressed without changing the constant values Rf, Cf, and C. A circuit can be constructed.

  A power converter as a surge voltage suppression circuit for suppressing a surge voltage generated at an input terminal of the generator or the motor or a time change rate dV / dt of the voltage by a cable connecting the power converter and the generator or the motor Applicable to.

The main circuit block diagram of the power converter device by Example 1 of this invention. FIG. 1 is a specific main circuit configuration diagram of a converter 11 in a power converter 1 according to a first embodiment of the present invention. The specific main circuit block diagram 2 of the converter 11 in the power converter 1 in Example 1 of this invention. FIG. 6 is a first waveform diagram illustrating the simulation of the voltage at the end of the generator or motor 4 according to the first embodiment of the present invention. FIG. 2 is a simulation waveform diagram 2 of a voltage at the end of the generator or motor 4 in Embodiment 1 of the present invention. The main circuit block diagram of the power converter device by Example 2 of this invention. The simulation waveform figure of the voltage in the generator or electric motor 4 end in Example 2 of this invention. The main circuit block diagram of the power converter device by Example 3 of this invention. FIG. 6 is a first waveform diagram illustrating the simulation of the voltage at the end of the generator or motor 4 according to the third embodiment of the present invention. FIG. 2 is a simulation waveform diagram 2 of the voltage at the end of the generator or motor 4 according to the third embodiment of the present invention. The main circuit block diagram of the power converter device by Example 4 of this invention. The schematic block diagram of the wind power generation system suitable for applying this invention. The main circuit block diagram of the power converter device by Example 5 of this invention. The main circuit block diagram of the power converter device by Example 6 of this invention. The block diagram 1 of the surge voltage suppression circuit in the power converter device by Example 7 of this invention. The block diagram 2 of the surge voltage suppression circuit in the power converter device by Example 7 of this invention. FIG. 3 is a configuration diagram of a surge voltage suppression circuit in a power conversion apparatus according to Embodiment 7 of the present invention (Part 3).

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Power converter, 11 ... Converter, 11A ... Converter, 11B ... Rectifier, 12 ... DC capacitor, 13 ... PWM inverter, 2, 2A-2F ... Surge voltage suppression circuit, 21 ... Reactor (inductance value Lf), 22 ... Resistance (resistance value Rf), 23 ... capacitor (capacitance Cf), 24 ... capacitor (capacitance C), 3 ... cable, 31 ... cable inductance Ll, 32 ... cable stray capacitance Cl, 4 ... generator or motor, 5 ... blade, 6 ... generator, 7 ... rotor shaft, 8 ... gear, 9 ... power system, 100 ... nacelle, 110 ... tower.

Claims (12)

  In a power conversion device in which a power converter is connected to a generator or an electric motor by a plurality of cables, a reactor is inserted into a cable connecting the power converter to the generator or an electric motor. A power converter comprising a series of capacitors connected in parallel.   2. The power conversion according to claim 1, wherein a capacitor is connected between each phase line of the cable connecting the reactor and the parallel circuit of the series body of the resistor and the capacitor and the generator or the motor. apparatus.   The power converter according to claim 1, wherein a plurality of intermediate taps are attached to the reactor, and one end of the series body of a resistor and a capacitor is connected to one of the intermediate taps.   In a power conversion device in which a power converter is connected to a generator or a motor by a plurality of cables, a parallel body of a reactor and a resistor is connected in a cable connecting the power converter and the generator or motor, and the parallel A capacitor is connected between each phase wire of the cable that connects a body and the generator or motor.   The power converter according to claim 4, wherein a plurality of intermediate taps are attached to the reactor, and one end of the resistor is connected to one of the intermediate taps.   In a wind power generation system including a windmill, a generator driven by the windmill, and a power converter connected to the generator by a plurality of cables, a cable connecting the power converter to the generator A wind power generation system in which a reactor is inserted into the reactor, and a series body of a resistor and a capacitor is connected in parallel to the reactor.   7. The wind power generation system according to claim 6, wherein a capacitor is connected between each phase line of the cable that connects the reactor and the parallel circuit of the series body of the resistor and the capacitor and the generator.   The wind power generation system according to claim 6, wherein a plurality of intermediate taps are attached to the reactor, and one end of the series body of a resistor and a capacitor is connected to one of the intermediate taps.   In a wind power generation system comprising a windmill, a generator driven by the windmill, and a power converter connected to the generator by a plurality of cables, the cable connecting the power converter and the generator A wind power generation system characterized in that a parallel body of a reactor and a resistor is connected therein, and a capacitor is connected between each phase line of the cable connecting the parallel body and the generator.   The wind power generation system according to claim 9, wherein a plurality of intermediate taps are attached to the reactor, and one end of the resistor is connected to one of the intermediate taps.   In a surge voltage suppression method for a power conversion apparatus in which a power converter is connected to a generator or a motor by a plurality of cables, a reactor is connected in a cable connecting the power converter and the generator or motor, and the reactor is connected to the reactor. On the other hand, a surge voltage suppression method for a power converter, comprising connecting a series body of a resistor and a capacitor in parallel.   In a surge voltage suppression method for a power conversion device in which a power converter is connected to a generator or a motor by a plurality of cables, a parallel body of a reactor and a resistor is connected in a cable connecting the power converter and the generator or motor. And the capacitor | condenser is connected between each phase wire of the said cable which connects this parallel body and the said generator or an electric motor, The surge voltage suppression method of the power converter device characterized by the above-mentioned.

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