JP2012044863A - Wind power generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the following problem: conventionally, excess or deficiency of reactive power occurs between a power supply that serves as a major part in a power system and a load of a system to which an electric power of the power system supplies electric power and, when the excess or deficiency exceeds the capability of existing voltage regulation equipment, it has become impossible to regulate the reactive power.SOLUTION: In the present invention, a voltage regulation device of a power system transmits a reactive power command corresponding to the power system to a wind power generator electrically connected with the power system. A wind power generator includes interface means that receives a reactive power command. Further, the wind power generator outputs reactive power according to a value obtained by adding, to the reactive power command, a reactive power command for suppressing voltage fluctuations caused by output power of the wind power generator.

Description

  The present invention relates to a wind power generator (wind power generation system and power system controller) that supplies reactive power necessary for the power system to the power system.

  Usually, a wind power generator converts wind energy into rotational energy to generate rotational torque in the rotor of the generator. Electric power is extracted from the torque generated at this time and output to the power system, thereby converting wind energy into active power and supplying the active power to a home or factory connected to the power system.

  In addition to the active power consumed by the resistance component, the power system includes reactive power consumed by the inductive component and capacitive component of the transmission line and load. When the inductive component of the load or line is large, the voltage decreases at the load end of the system, or the voltage increases when the capacity component of the load increases. Therefore, in order to maintain the voltage at an appropriate value, it is necessary to adjust the reactive power.

  At this time, the reactive power is usually adjusted by adjusting the voltage of the generator of the system, switching taps of transformers such as substations, power capacitors, shunt reactors, and synchronous phase adjusters. Further, in order to continuously control the value of reactive power using a capacitor or an inductance, various values of capacitors or inductance devices are required, and thus a device capable of continuously controlling reactive power may be used.

  The following Patent Document 1 and Patent Document 2 describe devices that output reactive power to a power system.

JP 2000-333373 A (hereinafter referred to as Reference 1) US20050046196 (hereinafter referred to as Reference 2)

  The problem to be solved by the present invention is that an excess or deficiency of reactive power occurs between a main power source (a large-capacity power source, for example, a thermal power plant) in a power system and a load of the power system. Reactive power cannot be adjusted when the capacity of the adjustment equipment (voltage adjustment of the generator, tap switching of transformers such as substations, power capacitors, shunt reactors, synchronous phase adjusters) is exceeded. is there.

  In addition, since the wind power generator outputs active power with large fluctuations, voltage fluctuations at the interconnection point of the wind power generation equipment are likely to occur.

  In Reference 1, a voltage command value is created to reduce reactive power to zero at a power reception point of a customer facility, or a voltage for adjusting a reactive power to control a power reception point voltage including a load and a distributed power source to be constant. A command value is created, and the voltage command value is used as a command value for voltage control of the distributed power source. For this reason, whether the reactive power is excessive or insufficient in the entire system is not considered in the control.

  In Reference 2, the reactive power command value is given from the farm controller, and excess or deficiency of the reactive power amount on the grid side is not considered in the reactive power control of the wind turbine generator. An object of the present invention is to supply reactive power necessary for maintaining the voltage of the power system to an appropriate value from the power generator to the power system.

  An interface device for receiving a first reactive power command value from a voltage detector provided in the power system; means for creating a second reactive power command value for suppressing fluctuations in output power of the generator; Means for calculating a third reactive power command value from the reactive power command value and the second reactive power command value, and outputting reactive power according to the third reactive power command value, The above problem can be solved by the wind power generator.

  Alternatively, a voltage detector that detects the voltage of the power system, a reactive power command value creation unit that creates a reactive power command value from the voltage detection value of the voltage detector, and transmits the reactive power command value to the wind turbine generator A power transmission system that suppresses output fluctuations of the generator and receives reactive power from the wind power generator according to the reactive power command. .

  Alternatively, a voltage detector that detects the voltage of the power system, a reactive power command value creation unit that creates a first reactive power command value from the voltage detection value of the voltage detector, and the first reactive power command value A transmission unit for transmitting to the wind power generator, wherein the wind power generator receives the first reactive power command value, and a second reactive power command for suppressing fluctuations in output power of the generator The third reactive power command value is calculated from the first reactive power command value and the second reactive power command value, and the reactive power is output according to the third reactive power command value. The above-mentioned problem can also be solved by a wind power generation system comprising:

A windmill that rotates in response to the wind, and a generator that generates electricity by rotation of the windmill,
In the wind power generator comprising a power converter that converts the power generated by the generator,
The wind power generator is electrically connected to a power system;
An interface device that receives a first reactive power command value created from a voltage detection value detected by a voltage detector provided in the power system;
Means for creating a second reactive power command value for suppressing voltage fluctuations due to fluctuations in output power of the generator;
Reactive power command value addition means for adding the first reactive power command value and the second reactive power command value;
And a means for outputting reactive power in accordance with a third reactive power command value output from the reactive power command value adding means (configuration 1).

In configuration 1,
In the case where the plurality of wind turbine generators are electrically connected to the power system,
The first wind turbine generator having a small output active power among the plurality of wind turbine generators outputs a reactive power larger than the second wind turbine generator having a large output active power. (Configuration 2).

In configuration 1,
When a plurality of the wind power generators are electrically connected to the power system,
The first wind turbine generator having a large output active power among the plurality of wind turbine generators outputs a reactive power smaller than the second wind turbine generator having a small output active power. (Configuration 3).

In configuration 1,
The interface device receives a delayed reactive power command value when a voltage detection value of the voltage detector is higher than a predetermined value,
When the voltage detection value is lower than a predetermined value, the advance reactive power command value is received,
A reactive power is output to the power system so that the voltage detection value falls within a predetermined range (configuration 4).

In configuration 1,
A wind power generator characterized in that it is provided with generated power control means capable of independently controlling active power and reactive power (Configuration 5).

A wind turbine including a wind turbine that rotates in response to wind, a generator that generates power by rotation of the wind turbine, and a power converter that converts power generated by the generator is electrically connected to a power system. In the wind power generation system
The power system includes a voltage detector for detecting a voltage of the power system;
Reactive power command value creation unit for creating a first reactive power command value from the voltage detection value of the voltage detector;
A transmission unit for transmitting the first reactive power command value to the wind turbine generator,
The wind turbine generator is configured to receive the first reactive power command value;
Means for creating a second reactive power command value for suppressing voltage fluctuations due to fluctuations in output power of the generator;
Reactive power command value addition means for adding the first reactive power command value and the second reactive power command value;
And a means for outputting reactive power in accordance with a third reactive power command value output by the reactive power command value adding means (configuration 10).

In configuration 10,
When a plurality of the wind power generators are electrically connected to the power system,
The first wind turbine generator having a small output active power among the plurality of wind turbine generators outputs a reactive power larger than that of the second wind turbine generator having a large output active power. (Configuration 11).

In configuration 10,
When a plurality of the wind power generators are electrically connected to the power system,
The first wind turbine generator having a large output active power among the plurality of wind turbine generators outputs a reactive power smaller than that of the second wind turbine generator having a small output active power. (Configuration 12).

In configuration 10,
The interface device receives a delayed reactive power command value when a voltage detection value of the voltage detector is higher than a predetermined value,
When the voltage detection value is lower than a predetermined value, the advance reactive power command value is received,
The wind power generation system is characterized in that reactive power is output to the power system so that the voltage detection value falls within a predetermined range (Configuration 13).

In configuration 10,
The wind power generator includes a generated power control unit that can control active power and reactive power independently (configuration 14).

  Even when the reactive power necessary for the power system is supplied from the wind turbine generator and the voltage fluctuation at the interconnection point by the wind turbine generator with large output fluctuation is suppressed, even if the capacity of the adjustment equipment such as voltage is exceeded, It is possible to adjust the voltage of the power system.

Explanatory drawing which showed the circuit structure of the electric power system and the wind power generator. Explanatory drawing which showed the structure of the wind power generator. Explanatory drawing which showed the implementation method of converter control. Explanatory drawing which showed the reactive power creation of a system voltage regulator. Explanatory drawing which showed the circuit structure of the multiple unit wind power generator. The relationship diagram of the reactive power command and output active power in a plurality of wind turbine generators. Explanatory drawing which showed the circuit structure at the time of using a synchronous machine type | mold for an electric power system and a wind power generator. Explanatory drawing which showed the structure of the wind power generator. Explanatory drawing which showed the implementation method of converter control.

  In order to make up for the purpose of supplementing the reactive power necessary for the power system with the output capacity not used by the wind power generation facility, the interface for receiving the reactive power command from the power system was provided in the wind power generation facility.

Example 1
FIG. 1 is a single-line diagram showing a device configuration of one embodiment of the present invention.

  First, the configuration of the power system will be described. The power generation facility 101 of the power system has a large capacity and can be considered as a power source. Since the electric power from the power generation facility 101 of the electric power system is sent using the transmission line, the impedance 102 of the transmission line exists. In order to convert the voltage of the transmission line to a low voltage, a transformer such as a substation is used, and a load 103 such as a home, a building, or a factory is connected. In addition, the wind power generator 104 is connected to a power transmission line in the same manner as the load 103.

  The substation uses a system voltage regulator 105 that adjusts the voltage of the load to be within a predetermined range by adjusting the turns ratio of the transformer or connecting a capacitor.

  The system voltage regulator 105 detects the voltage of the power system and transmits a reactive power command value necessary for maintaining the voltage to the wind power generator 104.

  Next, the configuration of the wind power generator will be described. The wind power generator 104 mainly includes a generator (winding induction generator) 104-01, a wing 104-02, a windmill controller 104-03, a converter (excitation device) 104-04, and a converter controller 104-05. Is done.

  The wing 104-02 is mechanically connected to the rotor of the generator 104-01, and the rotor winding of the generator 104-01 is electrically connected to the converter 104-04. The stator of −01 is electrically connected to the power system via the circuit breaker 104-06, the transformer 104-07, and the like.

  The windmill control device 104-03 detects the wind speed, controls the angle of the wing 104-02, calculates and outputs the active power command value Pref, outputs the operation / stop command value Run, and the reactive power command value Qref from the system voltage regulator 105. And transmission of the received reactive power command value Qref.

  Various command values such as the reactive power command value Qref, the active power command value Pref, and the operation / stop command value Run are sent to the converter control device 104-05. Converter control device 104-05 controls converter 104-04 according to the command value, and controls active power and reactive power between generator 104-01 and the system.

  Next, the wind power generator 104 will be described in detail with reference to FIG.

  The three-phase output on the stator side of the generator 104-01 is connected to the secondary side of the electromagnetic contactor 301. The primary side of the electromagnetic contactor 301 is connected to the primary side of the electromagnetic contactor 302. The secondary side of the magnetic contactor 302 is connected to the converter CNV via an AC filter circuit composed of a capacitor Cn and a reactor Ln.

  The DC circuit 303 of the converter CNV is connected to the DC circuit 303 of the converter INV, and the AC output of the converter INV is supplied to the rotor winding of the generator 104-01 through an AC filter circuit composed of a reactor Lr and a capacitor Cr. Is electrically connected. The primary side of the electromagnetic contactor 301 is also connected to the power system via the circuit breaker 104-06 and the transformer 104-07.

  For example, in order to protect the system of the wind power generator 104, the circuit breaker 104-06 opens the circuit breaker when the current is excessive, interrupts the current, completely stops the system of the wind power generator 104, and is electrically connected to the system. It has a function for separating.

  The converter INV on the generator side and the converter CNV on the power system side are configured using, for example, semiconductor switching elements (thyristors, GTO, IGBT, MOS, SiC, etc.), and the converter INV and the converter CNV each have an alternating current. It has a function of converting to direct current or converting direct current to alternating current.

  In addition, an AC filter configured of a reactor Ln and a capacitor Cn that attenuates the harmonic current and the harmonic voltage is installed at the AC output terminal of the converter CNV on the power system side.

  A blade for wind power generation is connected to the rotor of the generator 104-01 via a gear or the like, and rotates by receiving wind. In addition, a position detector 304 that detects a rotational position is connected to the rotor, and a position signal PLr is output.

  Next, wiring and devices for controlling the generated power will be described.

  The three-phase voltage and the three-phase current on the secondary side of the circuit breaker 104-06 are converted into the low voltage detection signal Vs and the low voltage current detection signal Is by the voltage sensor PTs and the current sensor CTs, respectively. The low voltage signals Vs and Is are input to the converter controller 104-05. The voltage between the electromagnetic contactor 301 and the stator of the generator 104-01 is converted into a low voltage signal Vg by the voltage sensor PTg and input to the converter controller 104-05.

  The voltage of the capacitor Cd connected to the converter INV and the DC section 303 of the converter CNV is converted into a low voltage DC voltage signal Edc by a voltage sensor, and the DC voltage signal Edc is input to the converter control device 104-05.

  Further, the detected value Ir of the output current of the converter INV detected by the current sensor CTr and the detected value In of the output current of the converter CNV detected by the current sensor CTn are transmitted to the converter control device 104-05.

  The windmill control device 104-03 sends various commands such as a start / stop command Run, an active power command Pref, and a reactive power command Qref to the converter control device 104-05, detects the state quantity of the windmill and the system, and communicates with the outside. It has a function.

  Converter control device 104-05 receives the detection signal of the output current of the wind turbine generator, the detection signal of the output voltage, and the reactive power command from the system voltage regulator, and calculates the active power command and the reactive power command.

  Converter control device 104-05 controls electromagnetic contactors 301 and 302 with signals Sg1 and Sg2 in accordance with the calculated active power command and reactive power command. Further, pulse signals Pulse_inv and Pulse_cnv for driving and controlling the respective converters INV and CNV constituted by semiconductor switching elements are output. At this time, the pulse signals Pulse_inv and Pulse_cnv input to the converters INV and CNV are generated so as to output reactive power necessary for the power system from the wind turbine generator and to suppress fluctuations in the output reactive power of the wind turbine generator. The

  The converter CNV controls the DC voltage Edc of the smoothing capacitor Cd to be constant. For this reason, converter CNV detects the phase of voltage detection value Vs, controls the current command value in phase with the detected voltage phase, exchanges active power with the system, and controls the DC voltage.

  If the generator side converter uses DC power to consume the energy of the smoothing capacitor and the DC voltage drops, the DC voltage control of the system side converter uses AC power to charge the smoothing capacitor Cd and detect the DC voltage. When the power converter INV charges the DC power and the DC voltage detection value Edc rises, the DC voltage control of the power converter CNV converts the DC power to AC power. It converts and discharges, and operates so as to keep the DC voltage detection value Edc constant.

  Next, detailed functions of converter control device 104-05 will be described with reference to FIG.

  The voltage detection value Vs is input to the phase detector THDET and the three-phase / two-phase converter 32trs. The phase detector THDET calculates a phase signal THs that follows the voltage of the power system {for example, in a phase locked loop (PLL) system} and outputs the phase signal THs (THs: power system U-phase voltage as a sine wave). Are output to the three-phase two-phase coordinate converters 32dqtrs-01 and 32dqtrs-02, the rotary coordinate converter dqtrs, the excitation phase calculator SLDET, and the two-phase three-phase coordinate converter dq23trs-01. The DC voltage command value Eref and the DC voltage detection value Edc are input to the DC voltage regulator DCAVR. The DC voltage regulator DCAVR adjusts the output p-axis current command value (effective current command value) Ipnstr so that the deviation between the input DC voltage command value Eref and the DC voltage detection value Edc becomes zero. 1-Output to ACR. Here, the DC voltage regulator DCAVR can be configured by, for example, a proportional-integral controller.

  The three-phase / two-phase coordinate converter 32dqtrs-01 uses the conversion formulas shown in Equations 1 and 2 from the input current In, and detects the p-axis current detection value Ipn (effective current) and the q-axis current detection value Iqn ( The reactive current is calculated, and the p-axis current detection value Ipn is output to the current regulator 1-ACR, and the q-axis current detection value Iqn is output to the current regulator 2-ACR.

Here, the subscripts u, v, and w represent phases. For example, the U phase current of In is represented as Inu.
The same applies to the voltage thereafter.

  The current adjuster 1-ACR adjusts the output p-axis voltage command value Vpn0 so that the deviation between the p-axis current command value Ipnstr and the p-axis current detection value Ipn is zero, and outputs it to the adder 401. Similarly, the current regulator 2-ACR adjusts and adds the output q-axis voltage command value Vqn0 so that the deviation between the q-axis current command value (zero in the figure) and the q-axis current detection value Iqn becomes zero. Output to the unit 402. Here, each current regulator (1-ACR, 2-ACR) can be constituted by, for example, a proportional integral controller.

  The three-phase / two-phase converter 32trs calculates the α component Vsα and the β component Vsβ from the input voltage Vs using the conversion equation shown in Equation 3, and outputs the result to the rotary coordinate converter dqtrs. The rotary coordinate converter dqtrs calculates the p-axis voltage detection value (phase component matching the system voltage vector) Vps and the q-axis voltage detection value (component orthogonal to the p-axis voltage detection value Vps) Vqs using Equation 4. Are output to the adders 401 and 402, respectively.

  The adder 401 adds the p-axis voltage command value Vpn0 and the p-axis voltage detection value Vps and outputs the result to the two-phase / three-phase coordinate converter dq23trs-01. Similarly, the adder 402 adds the q-axis voltage command value Vqn0 and the q-axis voltage detection value Vqs and outputs the result to the two-phase / three-phase coordinate converter dq23trs-01.

  The two-phase / three-phase coordinate converter dq23trs-01 receives the phase signal THs and the outputs Vpn and Vqn of each adder, and calculates the voltage command values Vun, Vvn, and Vwn according to the conversion equations shown in Equations 5 and 6. , Output to the PWM calculator PWMn.

  The PWM calculator PWMn calculates a gate signal Pulse_cnv for turning on / off n semiconductor elements constituting the converter CNV from the input voltage commands Vun, Vvn, Vwn by using a pulse width modulation method, and outputs it to the converter CNV. To do.

  A phase signal PLr indicating the rotational speed and position of the generator 104-01 is input to the rotational phase detector ROTETET. The rotational phase detector ROTDET counts the phase signal pulse PLr and converts it to a phase signal, and resets the phase signal to zero with one pulse per rotation (for example, a Z-phase pulse in an ABZ encoder). A phase signal RTH of 0 to 360 degrees that does not overflow is output to the adder 403.

  The phase signal RTH and the output phase signal LTH of the synchronous controller SYNC are added by the adder 403 to become the phase signal TH, and the phase signal TH is input to the excitation phase calculator SLDET together with the phase signal THs.

  The excitation phase calculator SLDET subtracts the phase signals TH and THs (THr = THs−TH), further multiplies the number of pole pairs of the generator, and outputs a phase signal THr of the electrical angular frequency of the generator rotor.

  The power calculator PQCAL includes the p-axis current Ips (the same direction as the U-phase vector of the system voltage) obtained by converting the system current Is by the conversion matrix shown in Equations 1 and 2, and the U-phase vector of the system voltage. The orthogonal q-axis current Iqs, the p-axis voltage detection value Vps, and the q-axis voltage detection value Vqs are input, and the active power Ps and reactive power Qs of the system are calculated by Equations 7 and 8.

  The active power adjuster APR receives the active power Ps and the active power command Pref of the wind turbine generator, and outputs the output effective current command value Ip0 so that the deviation between the power command value Pref and the detected power value Ps becomes zero. To do. Here, an example of the active power command will be described. However, in the case of a torque command, it is possible to control the torque command by multiplying it by the number of revolutions of the generator to convert it to an active power command. Unlike the torque control, the active power control can control the output power to be constant without being affected by the change in the rotational speed.

  Moreover, the reactive power command value Qref from the system voltage regulator 105 and the reactive power command value dQ for suppressing the voltage fluctuation caused by the active power Ps of the wind turbine generator are added. For example, dQ is created by α × Ps (α: proportional coefficient). The addition result Qref1 and reactive power Qs of each reactive power command value are input to the reactive power adjuster AQR, and an output excitation current command value Iq0 is output so that the deviation between the power command value Qref1 and the reactive power Qs becomes zero. Here, the power regulators APR and AQR can be constituted by, for example, proportional integrators.

  With this calculation method, it is possible to compensate for voltage fluctuations due to fluctuations in active power output by the wind turbine generator while compensating for reactive power that is insufficient in the system. The current command values Ip0 and Iq0 of each output of the active / reactive power regulator are input to the switch SW.

  The switch SW determines whether to use the outputs of the power regulators APR and AQR, or to use zero for the effective current command value and to use the output Iq1 of the voltage regulator AVR for the excitation current command value. SW uses zero for the effective current command value and the output of the voltage regulator for the excitation current command value before the electromagnetic contactor 301 is turned on, and each power adjustment after the electromagnetic contactor 301 is turned on Select the output of the instrument. Here, the time before the electromagnetic contactor 301 is turned on is the time of voltage synchronous operation in which the generator stator voltage is synchronized with the system voltage.

  The voltage regulator AVR will be described. The voltage regulator AVR receives the amplitude value Vgpk of the generator stator voltage Vg as a feedback value, and inputs a value Vsref obtained by filtering the amplitude value of the system voltage Vs as a command value, and the amplitude value of the generator stator voltage Vg. An exciting current command value Iq1 that makes the deviation between Vgpk and the command value Vsref zero is output to the switch SW. Here, the voltage regulator AVR can be constituted by, for example, a proportional integration controller. This voltage regulator AVR is operated from the converter INV to the generator 104-01, which is necessary for operating the electromagnetic contactor 301 in the open state and matching the amplitude value of the stator voltage of the generator Gen with the amplitude value of the system voltage. Adjust the excitation current command value that flows to the secondary side.

  The synchronous controller SYNC has a function for determining whether the generator voltage amplitude is synchronized from the command value Vsref and the generator stator voltage amplitude value Vgpk, and the phase of the system voltage and the stator voltage is different. Has a function of outputting a phase correction signal LTH for correcting it, and a function of determining whether the phase of the system voltage and the stator voltage are in a predetermined range and are synchronized, and the operation signal Sg1 of the circuit breaker And a control switching signal Sg0.

  Thus, the generator 104-01 can be synchronized with the system voltage before being connected to the power system, and can be quickly switched to the power control after being connected to the power system.

  The three-phase two-phase coordinate converter 32dqtrs-03 uses the conversion formulas shown in Equations 9 and 10 from the input current Ir and the rotor phase THr to calculate the q-axis current detection value Iqr (excitation current component) and the p-axis. The current detection value Ipr (effective component current component) is calculated, and the q-axis current detection value Iqr is output to the current regulator 4-ACR, and the p-axis current detection value Ipr is output to the current regulator 3-ACR.

  The current regulator 4-ACR adjusts the output q-axis voltage command value Vqr so that the deviation between the q-axis current command value Iq1 or Iq0 and the q-axis current detection value Iqr becomes zero. Similarly, the current regulator 3-ACR adjusts the output p-axis voltage command value Vpr so that the deviation between the p-axis current command value Ip1 or Ip0 and the p-axis current detection value Ipr is zero. Here, the current regulator can be constituted by a proportional integrator, for example.

  The p-axis voltage command value Vpr and the q-axis voltage detection value Vqr are input to the two-phase / three-phase coordinate converter dq23trs-02, and the two-phase / three-phase coordinate converter dq23trs-02 receives the phase signal THr and each input value from The voltage command values Vur, Vvr, and Vwr output from the two-phase / three-phase coordinate converter dq23trs-02 are calculated by the conversion equations shown in Equations 11 and 12, and are output to the PWM calculator PWMr.

  The PWM calculator PWMr calculates a gate signal Pulse_inv for turning on / off m semiconductor elements constituting the converter INV by the pulse width modulation method from the input voltage commands Vur, Vvr, Vwr, and outputs the gate signal Pulse_inv to the converter INV. .

  Next, the algorithm of the system voltage regulator 105 will be described with reference to FIG. As an algorithm of the system voltage regulator 105, when control is first started (S450), the system voltage regulator 105 detects a system voltage value VL on the load side of a home, for example, and the system voltage value VL is defined as an upper limit. It is compared whether it is larger than the value (S452). When the system voltage value VL is larger than the upper limit specified value, the value of the constant A is added (S454).

  If the system voltage value VL is smaller than the upper limit specified value, it is compared whether the system voltage value VL is smaller than the lower limit specified value (S456). When the system voltage value VL is smaller than the lower limit specified value, the value of the constant A is subtracted (S458). Further, when the system voltage value VL is larger than the lower limit specified value, the value of the constant A is not added or subtracted (S460).

  Then, the value of the reactive power command value Qref is calculated by adding the predetermined value Q multiplied by the constant A and the change width value Qstep (S462).

  As shown in FIG. 4, the system voltage regulator 105 detects a system voltage VL on the load side of, for example, a home, and when the voltage decreases, the reactive power command value is advanced in the forward direction. Changes the reactive power command value Qref so as to output delayed reactive power, and creates a reactive power command value so that the system voltage is within a predetermined range.

  The generated reactive power command value Qref is transmitted to the wind power generator 104 by a communication method such as a line or wireless. The wind power generator 104 outputs reactive power according to the received reactive power command value. In the present embodiment, the reactive power command value calculated by the grid voltage regulator 105 is transmitted to the wind power generator 104, but the voltage detection value detected by the grid voltage regulator 105 is transmitted to the wind turbine 104, The reactive power command value may be calculated by the wind power generator.

  Thus, the wind power generator outputs reactive power according to the reactive power command value from the equipment on the power system side, so that the system voltage can be adjusted and the installation of a synchronous phase adjuster, a power capacitor, and the like can be reduced.

  Also, as shown in FIG. 5, in the case of a wind farm in which a plurality of wind power generators are installed and centrally managed, the reactive power command value Qref is received by a controller that centrally manages and controls the entire farm, and the farm It is also possible to distribute the reactive power command value Qref to the wind power generation system operating within. For example, when the number of operating units is N, the reactive power command value commanded to one unit is set to 1 / N, or a wind power generator with a small power generation amount is distributed so as to output a large amount of reactive power .

  FIG. 6 shows a case where the reactive power command value Qref is distributed to each wind power generator when the wind power generator operating in a wind farm that is centrally managed with a plurality of wind power generators installed. An example of the relationship between the reactive power command value Qref and the active power output by each wind turbine generator is shown.

  As shown in FIG. 6, a reactive power command value smaller than that of other wind power generators is distributed to a wind power generator having a relatively large active power output within the farm. On the other hand, a reactive power command value larger than that of other wind turbine generators is distributed to the wind turbine generator with a relatively small active power output in the farm.

  By sending the command value so that the reactive power output of the wind turbine generator with low active power output is increased, it is possible to generate power without reducing the active power of the wind turbine generator.

  This is because a wind power generator with a large active power output has no room for increasing the reactive power output, and a wind power generator with a low active power output has a room for increasing the reactive power output. It is.

  Thus, in the wind turbine generator using the winding induction generator, the active power and the reactive power can be independently controlled on the generator side, but when the reactive power output is insufficient, the converter CNV directly connected to the system You may make up for the shortage.

(Example 2)
In the first embodiment, the wind power generation apparatus in which the winding induction generator is connected to the system by the converter has been described. However, the present invention can also be applied to the case where an induction generator or a synchronous generator as shown in FIG. 6 is used. In this embodiment, an embodiment in which a synchronous generator is used as a generator will be described.

  In FIG. 7, for example, a permanent magnet generator is used as a generator, and electric power extracted from the generator is AC-DC-AC converted by a converter and output to an electric power system.

  Functions of converter control device 604-05 will be described with reference to FIGS. In addition, what has the same control function is represented with the same code | symbol.

  The difference from the control of system side converter CNV of converter control device 604-05 is that the command value input to reactive current regulator 2-ACR is the reactive power command value in converter control device 604-05. is there.

  The phase signal PLr indicating the rotational speed and position of the generator 604-01 is input to the rotational phase detector ROTETET. A major difference from the converter control device 104-05 shown in FIG. 3 is that the rotational phase RTH is directly used as a phase signal in the phase detection method of the generator 604-01.

  The power calculator PQCAL converts the current detection value Ir detected by the current sensor CTr by the conversion matrix shown in the equations 1 and 2, and the obtained p-axis current Ipr (the same direction as the U-phase vector of the generator voltage) ), The q-axis current Iqr orthogonal to the U-phase vector of the system voltage, and the p-axis voltage Vpr and the q-axis voltage Vqr obtained by using the generator voltage Vr in the same conversion equation as in equations 3 and 4. The active power detection value Pr and the reactive power detection value Qr of the generator are calculated in the same manner as the equations (7) and (8).

  The active power adjuster APR receives the active power detection value Pr and the output power command Pref of the wind turbine generator, and outputs the effective divided current so that the deviation between the power command value Pref and the active power detection value Pr is zero. Command value Ip0 is output.

  The reactive power adjuster AQR is used to adjust the power factor of the generator. In order to keep the power factor at 1, zero is input to the command value. Zero is input as the reactive power detection value Qr and the reactive power command of the wind turbine generator, and an excitation current command value Ip0 is output for control.

  The three-phase two-phase coordinate converter 32dqtrs-03 uses the input current detection value Ir and the rotor phase RTH to convert the p-axis current detection value Ipr (effective component current component) using the conversion formulas shown in equations 9 and 10. The q-axis current detection value Iqr (excitation current component) is calculated, and the q-axis current detection value Iqr is output to the current regulator 4-ACR and the p-axis current detection value Ipr is output to the current regulator 3-ACR.

  The current regulator 4-ACR adjusts the output q-axis voltage command value Vqr so that the deviation between the q-axis current command value Iq1 or Iq0 and the q-axis current detection value Iqr becomes zero, and the current regulator 3-ACR The output p-axis voltage command value Vpr is adjusted so that the deviation between the p-axis current command value Ip0 and the detected p-axis current value Ipr is zero.

  The p-axis voltage command value Vpr and the q-axis voltage detection value Vqr are input to a two-phase / three-phase coordinate converter dq23trs-02, and the two-phase / three-phase coordinate converter dq23trs-02 receives the phase signal RTH, From the input values, the voltage command values Vur, Vvr, Vwr output from the converter dq23trs-02 are calculated by the conversion formulas shown in Expression 10 and Expression 11, and output to the PWM calculator PWMr.

  The PWM calculator PWMr calculates a gate signal Pulse_inv for turning on / off m semiconductor elements constituting the converter INV by a pulse width modulation method from the input voltage commands Vur, Vvr, Vwr, and outputs the gate signal Pulse_inv to the converter INV. To do.

  In this embodiment, the active power output from the converter CNV directly connected to the system is adjusted to match the input active power from the generator side, and the reactive power can be controlled independently of the active power according to the system status. Therefore, the same control is possible even if an induction generator is used as the generator.

  As described above, the wind power generator outputs reactive power according to the reactive power command value from the system side device, so that the system voltage can be adjusted and the installation of a synchronous phase adjuster, a power capacitor, and the like can be reduced.

  In addition, when multiple wind turbine generators are connected to the power grid, the wind power generator is effectively distributed by distributing the power command value so that the wind turbine generator with a low active power output outputs a large reactive power. Reactive power can be supplied efficiently without reducing power.

  According to the present invention, the wind turbine generator can supply reactive power necessary for the power system and suppress voltage fluctuations in the system. In addition to wind power generation, the present invention can be applied to a power source whose output power fluctuates because input energy cannot be controlled, for example, solar power generation using natural energy.

DESCRIPTION OF SYMBOLS 101 Power generation equipment 102 Transmission line impedance 103 Load 104 Wind power generator 104-01 Winding induction generator 104-02 Wing 104-03 Windmill controller 104-04 Converter 104-05 Converter controller 104-06 Circuit breaker 104- 07 Interconnection transformer 105 System voltage regulator Qref Reactive power command value Pref Active power command value Run Operation / stop command value Pitch * Wing angle command PTL Voltage detector VL System voltage detection value

Claims (4)

A power system electrically connected to a wind power generator comprising: a windmill that rotates by receiving wind; a power generator that generates power by rotation of the windmill; and a power converter that converts power generated by the power generator. In the power system control device for controlling
A voltage detector for detecting the voltage of the power system;
A reactive power command value creating unit that creates a reactive power command value from a voltage detection value of the voltage detector, and a transmission unit that transmits the reactive power command value to the wind turbine generator,
A power system control device that suppresses output fluctuations of the generator and transmits reactive power according to the reactive power command to the power system from the wind power generator. In claim 1,
When a plurality of the wind power generators are electrically connected to the power system,
The reactive power command value creation unit transmits a reactive power command value larger than that of the second wind power generator having a large output active power to the first wind power generator having a small output active power among the plurality of wind power generators. A power system control apparatus comprising: means for performing the operation. In claim 1,
When a plurality of the wind power generators are electrically connected to the power system,
The reactive power command value creation unit transmits a reactive power command value smaller than that of the second wind power generator having a small output active power to the first wind power generator having a large output active power among the plurality of wind power generators. A power system control apparatus comprising: means for performing the operation. In claim 1,
The reactive power command value creating unit creates a delayed reactive power command when the voltage detection value is higher than a predetermined value,
When the voltage detection value is lower than a predetermined value, the advance reactive power command is created,
A power system control apparatus, wherein the first reactive power command value is changed so that the voltage detection value falls within a predetermined range.

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