TWI393320B - System stabilization devices, methods, and wind power generation systems - Google Patents

Description

System stabilization device, method, and wind power generation system

The present invention relates to a system stabilization apparatus, method, and wind power generation system.

In the case of a wind power generator in which the system is connected in parallel, there is a case where a squirrel-cage induction generator is used. However, if the voltage on the power system side fluctuates due to a failure of the power system or the like, the induction generator side will The system side absorbs the remaining invalid power and cannot comply with the system parallel regulation. Therefore, when the system is connected in parallel by using a wind power generator of a squirrel-cage induction generator, it is known that a device for compensating for invalid power is separately provided in the wind power plant so as to be in parallel with the system.

[Patent Document 1] Japanese Laid-Open Patent Publication No. 2000-175360

However, as described above, in addition to the ineffective power compensation device in the wind power plant, it is necessary to carry out large-scale engineering such as civil engineering, so it is difficult to set invalid power for the environment of the wind power generation system with the existing squirrel cage induction generator. The problem of the compensation device.

The present invention has been made to solve the above problems, and an object thereof is to provide a system stabilization apparatus, method, and wind power generation system that can supply stable power without requiring a large-scale project.

In order to solve the aforementioned problems, the present invention employs the following parts.

A first aspect of the present invention is a system stabilization apparatus which is applied to a power generation system including: a power generation device having a squirrel-cage induction generator and generating power using natural energy; and the power generation device provided in the power generation device a connection switching unit that switches the connection between the power generation device and the power system and the non-connection with the power system; the system stabilization device includes an invalid power adjustment unit, wherein when the voltage of the power system satisfies a predetermined fluctuation condition, When the power generating device and the power system are in a non-connected state, the power system is supplied with invalid power, or the power system absorbs the invalid power.

According to such a configuration, if a ground fault or a short circuit occurs due to a lightning strike or the like, the voltage of the power system is reduced for a short period of time (several seconds or less), and the voltage of the power system satisfies a predetermined fluctuation condition, and the power generation device is driven from the power system by the connection switching unit. When it is in the non-connected state, the reactive power is supplied from the reactive power adjustment unit to the power system.

In this way, since the dedicated device (ineffective power adjustment unit) for adjusting the reactive power is provided, when the power system satisfies the fluctuation condition of the preset voltage, the stabilized reactive power can be supplied to the power system or absorbed by the power system. Invalid current.

In the system stabilization device, when the power generation device and the power system are in a non-connected state, a load connected to the power generation device via the connection switching unit may be provided.

As described above, when the power generating device and the power system are in a non-connected state, since the power generating device is connected to the load by the connection switching unit, the output of the power generating device can be supplied to the load, and the power generating device can be prevented from exceeding the number of revolutions. The load is, for example, a discharge resistor.

In the system stabilization device, the ineffective power adjustment unit may include a power storage device and a power converter.

As described above, in the case where the compensation of the reactive power is performed, since the power storage device can have a small capacity, the reactive power adjustment unit can be downsized. Thereby, it can be easily installed in an existing power generation system. Further, the power storage device is, for example, a battery or a capacitor.

In the system stabilization device, the ineffective power adjustment unit may have a mounting portion for mounting to the power system.

Thereby, it can be easily installed in an existing power generation system.

A second aspect of the present invention is a wind power generation system including: a power generator having a squirrel-cage induction generator and generating electricity by using a wind energy source; and the power generation device and the power system are provided between the power generation device and the power system to switch the power generation device and the power a connection and disconnection connection switching unit of the system; and when the voltage of the power system satisfies a predetermined fluctuation condition and the power generation device and the power system are disconnected, the power system is supplied with the reactive power Or an invalid power adjustment unit that absorbs invalid power by the aforementioned power system.

In the wind power generation system described above, when the power generation device and the power system are in a non-connected state, a load connected to the power generation device via the connection switching unit may be provided.

In the above-described wind power generation system, when the connection switching unit is connected to the power generating device and the load, when the output voltage of the power generating device side is smaller than a predetermined specific value, the output of the power generating device may be used. Grounded at the end.

A third aspect of the present invention is a system stabilization method, which is applied to a power generation system including: a power generation device having a squirrel-cage induction generator and generating power using natural energy; and the power generation device provided in the power generation device And a connection switching unit that switches the connection between the power generation device and the power system and the non-connection; and the system stabilization method is different from the power generation device in that the power supply adjustment unit is separately provided, and the voltage of the power system is When the power generation device and the power system are not connected to each other when the predetermined fluctuation condition is satisfied, the power supply is supplied with the reactive power or the power system absorbs the invalid power.

According to the present invention, it is possible to achieve the effect of not requiring large-scale civil engineering and supplying stable power of stability.

Hereinafter, an embodiment of the system stabilization apparatus, method, and wind power generation system of the present invention will be described with reference to the drawings.

In the present embodiment, a wind power generation system to which the system stabilization device of the present invention is applied will be described. Further, the generator of the present embodiment is, for example, a squirrel cage induction generator.

Fig. 1 is a block diagram showing a schematic configuration of a wind power generation system 1 to which a system stabilization device of the present embodiment is applied.

As shown in FIG. 1, the wind power generation system 1 of the present embodiment includes a wind turbine blade 10, a wind turbine rotor 11, a gear 12, a generator (power generation device) 13, a connection switching unit 14, a generator side voltage sensor 16, and a system. The side voltage sensor 17, the generator side current sensor 19, the control unit 18, and the system stabilization device 2.

In Fig. 1, a plurality of windmill blades 10 are attached to a windmill rotor 11. The generator 13 is connected to the main shaft of the windmill rotor 11 via a gear 12 having a specific gear ratio. The generator 13 is connected to the connection switching unit 14 by, for example, a three-phase power line, and the connection and disconnection with the power system 15 are switched by the connection switching unit 14. Further, the switching of the connection of the connection switching unit 14 is performed by the control unit 18.

The generator side voltage sensor 16 measures the voltage closer to the side of the generator 13 than the connection switching unit 14, and outputs the measurement result to the control unit 18. The system side voltage sensor 17 measures the voltage closer to the power system 15 side than the connection switching unit 14, and outputs the measurement result to the control unit 18.

Further, the generator-side current sensor 19 measures the current closer to the generator 13 side than the connection switching unit 14, and outputs the measurement result to the invalid power adjustment unit 21.

The control unit 18 switches the connection of the connection switching unit 14 based on the voltage values detected by the generator side voltage sensor 16, the system side voltage sensor 17, and the like, and the system stabilization device 2 (details are as follows) Control).

When a system failure or the like occurs so that the power of the power system 15 satisfies a predetermined fluctuation condition, the connection switching unit 14 operates in accordance with a signal from the control unit 18 to switch the engine 13 and the power system 15 from the connected state to the non-connected state. status. Specifically, when the voltage detected by the system side voltage sensor 17 satisfies a predetermined fluctuation condition, the connection switching unit 14 switches the generator 13 and the power system 15 to the non-connected state to cause the generator 13 Connected to the load 20. Further, in a state where the generator 13 is connected to the load 20, when the voltage of the generator 13 side detected by the generator side voltage sensor 16 is lower than a specific value, the connection switching portion 14 sets the generator 13 Switching to the non-connected state with the load 20 causes the output terminal of the generator 13 to be grounded. Further, in this state, when the wind speed condition on the side of the generator 13 reaches the state in which it can be connected in parallel with the power system 15 side, the connection switching unit 14 switches the generator 13 and the power system 15 to the connected state.

The system stabilization device 2 includes a load 20 and an invalid power adjustment unit 21.

When the generator 13 and the electric power system 15 are turned into the non-connected state, the load 20 is connected to the generator 13 via the connection switching portion 14. Specifically, the load 20 is a discharge resistor that consumes output power from the generator 13.

Further, when the load 20 and the generator 13 are connected via the connection switching unit 14, the wind turbine blade 10 controls the inclination angle by the control unit 18 or another control unit provided separately from the control unit 18 to reduce the wind turbine blade 10 Control of the number of revolutions.

In a state where the load 20 and the generator 13 are connected via the connection switching unit 14, the number of revolutions of the wind turbine rotor 11 immediately after the generator 13 and the power system 15 are not connected can be alleviated. Further, when the voltage on the side of the generator 13 detected by the generator-side voltage sensor 16 is lower than a specific value, the control unit 18 turns the connection between the generator 13 and the load 20 to be non-connected. The output of the motor 13 is grounded via the connection switching unit 14.

When the voltage of the power system 15 satisfies a predetermined fluctuation condition and the generator 13 and the power system 15 are in a non-connected state, the invalid power adjustment unit 21 supplies the reactive power to the power system 15 or the power system. 15 absorbs invalid power and adjusts invalid power. Further, the reactive power adjustment unit 21 includes a mounting portion (mounting portion) for mounting in the power system 15.

Specifically, the reactive power adjustment unit 21 includes a power storage device 211 , a power converter 212 , and a power adjustment control unit 213 .

The power adjustment control unit 213 determines the amount of the reactive current supplied to the power system 15 or absorbed from the power system 15 based on the voltage on the power system 15 side, and adjusts the reactive current of the determined flow rate between the power system 15 and the power storage device 211. .

More specifically, the power adjustment control unit 213 holds information that associates the voltage of the power system 15 with the reactive current, and based on the information, determines the voltage on the power system 15 side detected by the system side voltage sensor 17. The invalid current to be adjusted. Further, the power adjustment control unit 213 controls the amount of the reactive current that is supplied to the power system 15 or absorbed from the power system 15 as the voltage of the power system 15 approaches the normal reference voltage value.

The power converter 212 is an AC-DC converter that converts AC and DC. For example, when an invalid current of a flow rate determined by the power adjustment control unit 213 is supplied to the power system 15, the DC power stored in the power storage device 211 is converted into The power is exchanged, and the converted AC power is then output to the power system 15. Further, in order to absorb the ineffective current from the power system 15, the power converter 212 converts the AC power obtained from the power system 15 into DC power, and then outputs the converted power to the power storage device 211.

When the power generation system 13 is connected to the power system 15 and the power output from the power generator 13 is changed, the power adjustment control unit 213 can also discharge the power amount corresponding to the fluctuation from the power storage device 211. Alternatively, the power storage device 211 is stored, and the output of the generator 13 is equalized.

In this way, the invalid power supply unit 21 can supply the stabilized power to the power system 15 by equalizing the output of the power generator 13.

Next, the operation of the wind power generation system 1 of the present embodiment will be sequentially described in the case of normal operation and an abnormality in the power system at the time of power failure.

First, the case of normal operation will be described using FIG. 2.

The voltage of the generator 13 side is measured by the generator-side voltage sensor 16 at specific time intervals, and the measured value is output to the reactive power adjustment unit 21. The power adjustment control unit 213 of the reactive power adjustment unit 21 determines that the voltage value measured by the generator-side voltage sensor 16 is within a predetermined first voltage range (for example, ±10% with respect to the reference voltage (0.9) It is up to 1.1Pu)) whether it changes with the reference voltage (step SA1).

As a result, when the voltage value measured by the generator-side voltage sensor 16 fluctuates within the first voltage range, the power storage device 211 is discharged or the power storage device 211 is made to equalize the fluctuation portion. Charging (step SA2). For example, the effective power calculated based on the voltage and current measured by the generator-side voltage sensor 16 and the generator-side current sensor 19 is lower than the set value because the wind speed condition is not reached, the wind is weak, and the like. In the case where the power converter 212 compensates for the portion of the effective power that is lower than the set value, the power stored in the power storage device 211 is DC-converted by the power converter 212, and the converted power is supplied to the power system 15 . .

Further, when the effective electric power calculated by the voltage and current measured by the generator side voltage sensor 16 and the generator side current sensor 19 rises higher than the set value due to strong wind power or the like, the electric power is generated. The converter 212 converts the excess effective power of the portion higher than the set value by the power converter 212, and stores the converted power in the power storage device 211.

Then, the power adjustment control unit 213 determines whether or not the output voltage of the generator-side voltage sensor 16 is stable. If it is stable, the process returns to step SA1 and continues to monitor the fluctuation of the output voltage of the generator-side voltage sensor 16. If the output voltage of the generator side voltage sensor 16 is not stable, the process returns to step SA2, and the above discharge or charging is continued until the output of the generator changes stably (step SA3).

In this way, the power adjustment control unit 213 monitors the output power supplied from the power generator 13 to control the charging and discharging of the power storage device 211, and equalizes the power output from the power generator 13.

Next, a case where an abnormality occurs in the power system 15 will be described with reference to FIG. 3.

The voltage of the power system 15 is measured by the system side voltage sensor 17, and the measurement result is notified to the control unit 18. In the power system 15, when the voltage of the power system 15 satisfies the fluctuation condition defined by the combination of the fluctuation amount and the time due to the system failure, the control unit 18 detects the fluctuation of the voltage of the power system 15 (step SB1). ). Further, the fluctuation condition is a setting such as, for example, a state in which the voltage of the power system 15 as a reference +20% continues for 150 msec or more; when the state of the reference voltage +10% continues for 3 seconds or more; or -10% When the state lasts for more than 40 milliseconds, etc.

When the control unit 18 detects that the voltage of the power system 15 satisfies the fluctuation condition, the control unit 18 controls the connection switching unit 14 to turn the generator 13 and the power system 15 into a non-connected state, and connects the generator 13 to the load 20. . Thereby, the rapid increase in the number of revolutions of the wind turbine rotor 11 immediately after the generator 13 and the power system 15 are not connected can be alleviated, and the overspeed of the wind turbine rotor 11 can be prevented (step SB2).

Further, in order to suppress the number of revolutions of the wind turbine rotor 11, the inclination angle of the wind turbine blade is controlled on the fin side, and the output of the power generator 13 is gradually lowered. When the output of the generator 13 falls below a certain value, the control unit 18 switches the connection target of the connection switching unit 14 and grounds the generator 13 via the connection switching unit 14 (step SB3).

Further, while the control as described above is performed, the voltage of the power system 15 is measured by the system side voltage sensor 17 on the voltage system 15 side, and the measured value is output to the power adjustment control unit 213. The power adjustment control unit 213 determines an invalid current corresponding to the voltage detected by the system side voltage sensor 17 based on the setting table held by itself. The power adjustment control unit 213 supplies the determined ineffective current to the power system 15 and discharges it from the power storage device 211, and converts the discharged DC power to AC power conversion by the power converter 212, and outputs it to the power system 15 (step SB2). ).

Then, when the wind speed condition or the like for rotating the wind turbine rotor 11 on the generator 13 side is reached, and the voltage of the electric power system 15 approaches the reference voltage (step SB4), the control unit 18 controls the connection switching unit 14 to cause the generator 13 to The power system 15 is connected such that the generator 13 is in a system parallel state (step SB5).

In this manner, when the voltage of the power system 15 satisfies the preset fluctuation condition, the generator 13 and the power system 15 are brought into a non-connected state, and the dedicated device for adjusting the reactive power (the reactive power adjustment unit 2) is turned off. Since the invalid power is adjusted, the stabilized invalid power can be supplied to the power system 15 or absorbed from the power system 15.

As described above, the system stabilization device 2, the method, and the wind power generation system 1 according to the present invention are the generator 13 and the power when the voltage of the power system 15 satisfies a predetermined fluctuation condition due to a system failure or the like. The system 15 is connected to the load 20 by the connection switching unit 14 being turned into the non-connected state, and a dedicated device (ineffective power adjusting unit 21) for supplying the invalid power is connected to the power system 15 side.

Thereby, when the voltage of the power system 15 satisfies the fluctuation condition and the generator 13 and the power system 15 are not connected, the connected invalid power adjustment unit 21 can supply the stabilized invalid power to the power system 15 . Or absorbed from the power system 15. Thereby, the existing wind power generator of the squirrel-cage induction generator can be directly used, and the invalid power in the system failure can be stabilized.

Further, when the generator 13 and the power system 15 are turned into the non-connected state, the generator 13 is connected to the load 20 (for example, a discharge resistor) to output the output of the generator 13 to the discharge resistor, and the power is discharged by the discharge resistor. Consumption. Thereby, the rapid increase in the number of revolutions of the wind turbine rotor 11 immediately after the generator 13 and the power system 15 are in the non-connected state can be alleviated, and the overspeed of the wind turbine rotor 11 can be prevented.

Further, since the system stabilization device 2 includes the load 20, the power storage device 211, the power converter 212, and the like, it can be installed in a wind power generation system including an existing squirrel-cage induction generator, and can be easily installed.

The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to the embodiment, and design changes and the like without departing from the scope of the invention are included.

1. . . Wind power system

2. . . System stabilization device

13. . . generator

14. . . Connection switching unit

15. . . Power Systems

16. . . Generator side voltage sensor

17. . . System side voltage sensor

18. . . Control department

20. . . load

twenty one. . . Invalid power adjustment department

211. . . Power storage device

212. . . AC to DC converter

213. . . Power adjustment control department

1 is a block diagram showing an example of a wind power generation system to which a system stabilization device according to an embodiment of the present invention is applied;

Figure 2 is a diagram showing the flow of operations during normal operation of the system stabilization device of the present invention;

Fig. 3 is a view showing an operational flow of a case where the system voltage of the system stabilization apparatus of the present invention is lowered.

1. . . Wind power system

2. . . System stabilization device

13. . . generator

14. . . Connection switching unit

15. . . Power Systems

16. . . Generator side voltage sensor

17. . . System side voltage sensor

18. . . Control department

20. . . load

twenty one. . . Invalid power adjustment department

211. . . Power storage device

212. . . AC to DC converter

213. . . Power adjustment control department

Claims (8)

A system stabilization device for use in a power generation system, comprising: a power generation device having a squirrel-cage induction generator and generating power using natural energy; and being disposed between the power generation device and the power system to switch the power generation a connection and disconnection connection unit between the device and the power system; the system stabilization device includes an invalid power adjustment unit, wherein the power generation device and the power system become non-volatile when the voltage of the power system satisfies a predetermined fluctuation condition In the case of the connected state, the power system is supplied with invalid power, or the power system absorbs the invalid power. The system stabilization device according to claim 1, wherein when the power generation device and the power system are in a non-connected state, a load connected to the power generation device via the connection switching unit is provided. The system stabilization device according to claim 1 or 2, wherein the reactive power adjustment unit includes a power storage device and a power converter. The system stabilization device of claim 3, wherein the invalid power adjustment unit has a mounting portion for mounting to the power system. A wind power generation system comprising: a squirrel-cage induction generator and a power generation device that generates power by using a wind energy source; and is disposed between the power generation device and the power system to switch the connection and non-connection connection between the power generation device and the power system a switching unit; and when the voltage of the power system meets a predetermined fluctuation condition, When the power generation device and the power system are in a non-connected state, the power supply system supplies the reactive power to the power system, or the reactive power adjustment unit that absorbs the reactive power from the power system. The wind power generation system according to claim 5, wherein a load connected to the power generation device via the connection switching unit is provided when the power generation device and the power system are disconnected. The wind power generation system according to claim 5 or 6, wherein the connection switching unit is in a state where the power generating device is connected to the load, and when the output voltage of the power generating device side is smaller than a predetermined specific value, The output end of the aforementioned power generating device is grounded. A system stabilization method, which is applied to a power generation system, comprising: a power generation device having a squirrel-cage induction generator and generating power using natural energy; and being disposed between the power generation device and the power system to switch the power generation a connection and disconnection connection unit between the device and the power system; the system stabilization method is different from the power generation device in that the power supply adjustment unit is separately provided, and when the voltage of the power system satisfies a predetermined fluctuation condition, When the power generating device and the power system are in a non-connected state, the power system is supplied with the reactive power, or the power system absorbs the invalid power.