JP5409197B2 - Secondary excitation type power generation system - Google Patents

Description

  The present invention relates to a secondary excitation power generation system corresponding to disturbances in a power system.

  Due to the disturbance of the power system, an excessive current is generated in the rotor winding of the secondary excitation generator, an excessive current flows into the power converter, and the power converter is stressed. For this reason, in the prior art, as shown in [Patent Document 1] and [Patent Document 2], in order to reduce the stress of the power converter, a thyristor in the crowbar circuit is turned on, and an excessive current of the rotor winding Was dealt with by flowing the thyristor in the crowbar circuit.

Japanese Patent Laid-Open No. 11-18486 JP 2007-244136 A

  In the conventional technique, after the thyristor in the crowbar circuit is turned on, when the rotor continues to rotate, a voltage is excited in the rotor winding by the residual magnetic flux, and the thyristor continues to be turned on. When the thyristor continued to be on, the rotor winding of the secondary excitation generator was short-circuited, and the rotor-side converter could not be operated, so the secondary excitation generator could not generate power.

  An object of the present invention is to provide means for enabling a secondary excitation type power generation system to generate power after a thyristor is turned on.

  In order to achieve the above object, the present invention provides a secondary excitation in which a rotor-side converter is connected to the rotor-side winding of a secondary excitation generator, and a thyristor is connected in parallel to the converter through a diode. In the type power generation system, after the thyristor is ignited, the rotation of the secondary excitation generator is stopped.

  Furthermore, in the secondary excitation type power generation system according to the present invention, for the wind turbine connected to the secondary excitation type generator, the rotation of the secondary excitation type generator is stopped by changing the blade pitch of the wind turbine. It is characterized by this.

  According to the present invention, power generation can be resumed after an excessive current in the rotor winding is released by the crowbar circuit.

1 is an explanatory diagram of a circuit configuration of a wind turbine generator according to Embodiment 1. FIG. Explanatory drawing of the circuit structure of the wind power generator of Example 2. FIG. Explanatory drawing of the circuit structure of the wind power generator of Example 3. FIG. Explanatory drawing of the circuit structure of the wind power generator of Example 4. FIG. Explanatory drawing of the circuit structure of the wind power generator of Example 5. FIG.

  In the power converter according to the present invention, after the thyristor in the crowbar circuit is turned on, the rotor of the secondary excitation generator is stopped, the current flowing to the thyristor is reduced, and the thyristor is turned off, so that the secondary excitation power generation Enable the system to generate electricity. Details of the embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a circuit diagram showing a configuration of a first embodiment of the present invention. Here, a wind power generator will be described as an example, but it can also be applied to other uses such as pumped-storage power generation.

  First, the circuit and device for outputting the generated power in FIG. 1 will be described. The wind power generator is a secondary excitation generator, and the stator side winding of the secondary excitation generator 9 is connected to, for example, the stator side circuit breaker 2 that can be opened and closed by an external signal. The circuit breaker 2 is connected to the circuit breaker 3 on the converter side and the power system 1. The circuit breaker 3 is connected to the AC side of the power converter 6 on the system side through a converter-side capacitor 5 and a converter-side reactor 4 that are Y-connected, for example. The DC side of the power converter 6 on the system side is connected to the DC side of the power converter 7 on the rotor side through a smoothing capacitor. The AC side of the rotor-side power converter 7 is connected to the rotor winding of the secondary excitation generator 9 via the rotor-side reactor 8.

  The AC side of the rectifier 10 is connected in parallel to the AC side of the power converter 7 on the rotor side, and the DC side of the rectifier 10 is connected to the thyristor 11. The rotor of the secondary excitation generator 9 is connected to a wind turbine 20 for wind power generation via a gear, a clutch, and the like, and rotates by receiving wind force. The power converter 6 on the system side and the power converter 7 on the rotor side are configured using, for example, power semiconductor switching elements (GTO, IGBT, power MOSFET, etc.). It has a function to convert to alternating current.

  Next, the reason why the thyristor 11 described in the problem to be solved by the invention continues to be turned on will be described. Due to the disturbance of the power system, an excessive current is generated in the rotor winding of the secondary excitation generator 9, an excessive current flows into the power converter 7 on the rotor side, and stress is applied to the power converter 7 on the rotor side. . In order to reduce the stress of the power converter 7 on the rotor side, the thyristor 11 in the crowbar circuit is turned on, and an excessive current of the rotor winding is passed through the thyristor 11. At the same time that the thyristor 11 is turned on, the circuit breaker 2 on the stator side is opened, and the secondary excitation generator 9 is disconnected from the power system 1, but residual magnetic flux remains in the iron core of the stator of the secondary excitation generator 9. Therefore, when the rotor of the secondary excitation generator 9 is rotating, a voltage is excited in the rotor winding of the secondary excitation generator 9. Since the voltage of the rotor winding of the secondary excitation generator 9 is applied to the thyristor 11 via the rectifier 10, the thyristor 11 continues to be turned on when the secondary excitation generator 9 continues to rotate.

  Next, a configuration that allows the secondary excitation power generation system to resume power generation in Embodiment 1 of the present invention will be described. The reason why the thyristor 11 continues to be on is that the secondary excitation generator 9 continues to rotate. Therefore, in order to turn off the thyristor 11, for example, the rotation of the rotor of the secondary excitation generator 9 is stopped by changing the pitch of the blade so that the rotation of the windmill 20 does not receive wind on the blade of the windmill 20. Thus, the voltage excited in the rotor winding is reduced, the current flowing through the thyristor is made equal to or lower than the holding current of the thyristor, and the thyristor 11 is turned off, so that the power converter 7 on the rotor side can be operated, Control so that the secondary excitation power generation system can resume power generation.

  FIG. 2 is a circuit diagram showing the configuration of Embodiment 2 of the present invention. A wind power generator will be described as an example in the same manner as in the first embodiment, but it can also be applied to other uses such as pumped-storage power generation.

  First, differences between the configurations of FIGS. 1 and 2 will be described. FIG. 2 differs from the configuration of FIG. 1 in that a contactor 12 for short-circuiting the rotor is added.

  Next, a configuration that enables the secondary excitation power generation system according to the second embodiment of the present invention to resume power generation will be described. When the rotor of the secondary excitation generator 9 is rotating, a voltage is excited in the rotor winding of the secondary excitation generator 9, but the rotor winding of the secondary excitation generator 9 Since the voltage is applied to the thyristor 11 via the rectifier 10, the thyristor 11 continues to be turned on. Therefore, the voltage applied to the thyristor 11 is reduced by short-circuiting the rotor winding of the secondary excitation generator 9 with the contactor 12 for short-circuiting on the rotor side, and the current flowing through the thyristor is reduced to the holding current of the thyristor. In the following, the thyristor 11 is turned off, so that the power converter 7 on the rotor side can be operated, and control is performed so that the secondary excitation power generation system can resume power generation.

  As described above, the second embodiment has an advantage that the secondary excitation power generation system can resume power generation without stopping the rotor of the secondary excitation generator 9.

  FIG. 3 is a circuit diagram showing a configuration of Embodiment 3 of the present invention. A wind power generator will be described as an example in the same manner as in the first embodiment, but it can also be applied to other uses such as pumped-storage power generation.

  First, differences between the configurations of FIGS. 1 and 3 will be described. FIG. 3 is different from the configuration of FIG. 1 in that a rectifier disconnecting contactor 13 is added.

  Next, a configuration that enables the secondary excitation power generation system according to the third embodiment of the present invention to resume power generation will be described. By separating the rectifier 10 and the thyristor 11 from the rotor winding of the secondary excitation generator 9 with the contactor 13 for separating the rectifier, the voltage applied to the thyristor 11 is reduced and the thyristor 11 is turned off. Thus, the rotor-side power converter 7 can be operated so that the secondary excitation power generation system can resume power generation.

  Similarly to the second embodiment, the third embodiment has an advantage that the secondary excitation power generation system can resume power generation without stopping the rotor of the secondary excitation generator 9.

  FIG. 4 is a circuit diagram showing the configuration of Embodiment 4 of the present invention. A wind power generator will be described as an example in the same manner as in the first embodiment, but it can also be applied to other uses such as pumped-storage power generation.

  First, differences between the configurations of FIGS. 1 and 4 will be described. FIG. 4 is different from the configuration of FIG. 1 in that a commutation circuit 14 is added.

  Next, a configuration that enables the secondary excitation power generation system according to the fourth embodiment of the present invention to resume power generation will be described. All current flowing through the thyristor 11 is passed to the commutation circuit 14 side, and the thyristor 11 is turned off so that the power converter 7 on the rotor side can be operated, and control is performed so that the secondary excitation power generation system can resume power generation. To do.

  Similarly to the second embodiment, the fourth embodiment has an advantage that the secondary excitation power generation system can restart the power generation without stopping the rotor of the secondary excitation generator 9.

  FIG. 5 is a circuit diagram showing a configuration of the fifth embodiment. A wind power generator will be described as an example in the same manner as in the first embodiment, but it can also be applied to other uses such as pumped-storage power generation.

  First, differences between the configurations of FIGS. 1 and 5 will be described. FIG. 5 shows an energy consuming device 16 connected in parallel to the thyristor 11 of the crowbar circuit from the DC side of the power converter 6 on the system side and the power converter 7 on the rotor side through the discharge resistor 15 in the configuration of FIG. Differences are added.

  Next, the configuration and operation of Embodiment 5 of the present invention will be described. In order to discharge the electric charge of the smoothing capacitor 17 on the DC side between the power converter 6 on the system side and the power converter 7 on the rotor side during the stop, the thyristor 11 or the energy consuming device 16 is operated via the discharge resistor 15. Thus, the electric charge of the smoothing capacitor 17 is discharged. When the charge of the smoothing capacitor 17 is discharged by turning on the thyristor 11, it is necessary to turn off the thyristor 11 by stopping the rotor of the secondary excitation generator 9 as in the first embodiment. However, when the charge of the smoothing capacitor 17 is discharged by the energy consuming device 16, when a self-extinguishing type switching element such as a bipolar transistor, IGBT, or power MOSFET is used as the switching element 18 in the energy consuming device 16, Since the switching element 18 can be turned off regardless of the voltage applied to the switching element 18, the secondary excitation type power generation system can restart power generation without stopping the rotor of the secondary excitation type generator 9. Can be realized.

  The secondary excitation type power generation system of the present invention can be applied to a power generation system using other secondary excitation type generators such as a pumped storage power generation system in addition to a wind power generator system.

DESCRIPTION OF SYMBOLS 1 Electric power system 2 Stator side circuit breaker 3 Converter side circuit breaker 4 Converter side reactor 5 Converter side capacitor 6 System side power converter 7 Rotor side power converter 8 Rotor side reactor 9 Secondary excitation type Generator 10 Rectifier 11 Thyristor 12 Rotor side short-circuit contactor 13 Rectifier disconnecting contactor 14 Commutation circuit 15 Discharge resistor 16 Energy consumption device 17 Smoothing capacitor 18 Switching element

Claims (2)

A rotor-side converter is connected to the rotor-side winding of the secondary excitation generator, and a circuit breaker for disconnecting from the power system is connected to the stator-side winding of the secondary excitation generator. In a secondary excitation type power generation system in which a thyristor is connected in parallel to the converter through a diode, the circuit breaker is opened as the thyristor is ignited, and after the thyristor is ignited , The rotation of the secondary excitation generator is stopped so that the voltage excited in the rotor winding is reduced against the residual magnetic flux remaining in the iron core so that the current flowing through the thyristor is less than the holding current. Secondary excitation type power generation system characterized by The secondary excitation power generation system according to claim 1, wherein the rotation of the secondary excitation generator is stopped by changing a blade pitch of the wind turbine with respect to the wind turbine connected to the secondary excitation generator. Secondary excitation type power generation system characterized by

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