WO2021024322A1 - Renewable energy power plant system and plant control device - Google Patents

Renewable energy power plant system and plant control device Download PDF

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Publication number
WO2021024322A1
WO2021024322A1 PCT/JP2019/030587 JP2019030587W WO2021024322A1 WO 2021024322 A1 WO2021024322 A1 WO 2021024322A1 JP 2019030587 W JP2019030587 W JP 2019030587W WO 2021024322 A1 WO2021024322 A1 WO 2021024322A1
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power
pseudo
renewable energy
value
phase angle
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PCT/JP2019/030587
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French (fr)
Japanese (ja)
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康晃 三ッ木
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東芝三菱電機産業システム株式会社
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Priority to JP2021538542A priority Critical patent/JP7226560B2/en
Priority to PCT/JP2019/030587 priority patent/WO2021024322A1/en
Publication of WO2021024322A1 publication Critical patent/WO2021024322A1/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers

Definitions

  • This application relates to a renewable energy power plant system and a plant control device.
  • a plant system including a power system stabilizer is known.
  • the power system stabilizer of the above-mentioned conventional technique is constructed so as to disconnect the generator and stop the renewable energy power generation device in the event of a system accident. Disengagement of generators in the event of a system accident can prevent the generators from stepping out, and stopping the renewable energy generator can reduce the number of generators required to stabilize the power system.
  • the synchronous generator may perform unfavorable acceleration operation.
  • the synchronous generator is provided with a governor.
  • This governor is a speed governor for controlling the speed of a synchronous generator.
  • the speed governor provided in the synchronous generator is generally a mechanical device, the response speed is slow.
  • This slow response speed is, for example, a slow time constant of 1 second or more. Due to such a slow response speed, the speed control function of the conventional synchronous generator has a problem that the effect of suppressing unfavorable acceleration such as one-wave acceleration detuning is low.
  • This application was made to solve the above-mentioned problems, and an object of the present application is to provide a renewable energy power generation plant system and a plant control device equipped with a speed control function capable of high-speed response.
  • the renewable energy power plant system is A renewable energy power plant system that is connected to a bus in the vicinity of a synchronous generator via a step-up transformer or transmission line.
  • Renewable energy generator and A power conversion device that converts DC power generated by the renewable energy power generation device into AC power
  • a plant control device that controls the power conversion device based on the system voltage and system current of the grid interconnection point on the output side of the power conversion device.
  • the plant control device includes a frequency droop block for calculating an active power output upper limit value of the power conversion device.
  • the frequency droop block calculates a pseudo-angular velocity, which is an angular frequency obtained from the frequency of the system voltage, and a pseudo-internal phase angle based on an integral value of the pseudo-angular velocity.
  • the frequency droop block is constructed so that when the absolute value of the pseudo internal phase angle is equal to or greater than a predetermined reference phase angle, the active power output upper limit value is lowered when the pseudo angular velocity increases. ..
  • the plant control device is constructed to control a power converter included in a renewable energy power plant system connected to a bus in the vicinity of a synchronous generator via a step-up transformer or transmission line, which power converter is said to be the renewable energy.
  • a plant control device that converts DC power generated by a renewable energy power generation device included in a power plant system into AC power.
  • the plant controller A power command calculation block constructed to transmit a power command value calculated based on the system voltage and system current of the grid interconnection point on the output side of the power converter to the power converter.
  • a frequency droop block that calculates the upper limit of the active power output of the power converter, and Including The frequency droop block calculates a pseudo-angular velocity, which is an angular frequency obtained from the frequency of the system voltage, and a pseudo-internal phase angle based on an integral value of the pseudo-angular velocity.
  • the frequency droop block is constructed so that when the absolute value of the pseudo internal phase angle is equal to or greater than a predetermined reference phase angle, the active power output upper limit value is lowered when the pseudo angular velocity increases. ..
  • the plant control device is provided with the frequency droop block, high-speed processing is possible, so that the speed control function by the frequency droop block can be differentiated at a high response speed.
  • the active power output of the power converter can be reduced at a high response speed so as to suppress the occurrence of undesired acceleration in the interconnected synchronous generators.
  • FIG. 1 is a diagram showing a configuration of a renewable energy power generation plant system 4 according to an embodiment.
  • the renewable energy power generation plant system 4 is connected to the synchronous generator system 3 via a bus 30.
  • FIG. 1 illustrates a grid-connected power system 1 including a renewable energy power plant system 4 and a synchronous generator system 3.
  • Reference numeral 50 in FIG. 1 schematically illustrates a system accident.
  • the synchronous generator 3a and the renewable energy power generation plant system 4 are interconnected in the vicinity.
  • the term “neighborhood” here means that the electrical distance is short, rather than the geographical meaning.
  • the output of the renewable energy power generation plant system 4 is suppressed when the synchronous generator 3a is accelerating, the acceleration of the synchronous generator 3a becomes moderate, and the synchronous generator 3a and the renewable energy power generation are performed. It is interconnected with the plant system 4 in the vicinity.
  • the synchronous generator 3a and the renewable energy power generation plant system 4 are connected to the same bus 30 via a step-up transformer or a transmission line having a relatively short length. It is more preferable that they are provided in the same substation.
  • the renewable energy power plant system 4 includes a current transformer 7a, an instrument transformer 7b, an interconnection transformer 5, a plurality of switches 6, a plurality of transformers 8, a plurality of power converters 9, and a plurality of transformers.
  • the DC power supplies 11 and 12 are provided.
  • one end of the interconnection transformer 5 is connected to the connection point 32 of the bus 30.
  • the other end of the interconnection transformer 5 is connected to one end of each of the plurality of switches 6.
  • the other end of each of the plurality of switches 6 is connected to one end of each of the plurality of transformers 8.
  • the other end of each of the plurality of transformers 8 is connected to the AC output end of each of the plurality of power conversion devices 9.
  • the signal outputs of the current transformer 7a and the instrument transformer 7b are transmitted to the plant control device 10.
  • the plant controller 10 can measure the value of the value and the system voltage V s of the system current Is of the grid interconnection point.
  • the DC power supply 11 is a renewable energy power generation device.
  • the renewable energy power generation device is a power generation device whose amount of power generation depends on the weather, and may be a solar cell array including a solar cell module or a wind power generator.
  • the renewable energy power generation device according to the embodiment is, for example, a solar cell module.
  • the DC power supply 12 is a storage battery. In the embodiment, a plurality of DC power supplies 12 are provided.
  • the plurality of power conversion devices 9 convert DC power from the plurality of DC power sources 11 and 12 into AC power.
  • the power conversion device 9 is a three-phase AC inverter circuit constructed of a plurality of semiconductor switching elements.
  • the power converter 9 is also referred to as a power conditioner system (PCS).
  • the plurality of power conversion devices 9 include a first power conversion device 9 and a second power conversion device 9.
  • the power conversion device 9 connected to the DC power supply 11 is referred to as a "first power conversion device 9".
  • the power conversion device 9 connected to the DC power supply 12 is referred to as a "second power conversion device 9".
  • the energy storage system (Energy Storage System: ESS) 20 is constructed by the second power conversion device 9 and one DC power supply 12. From this, the power storage system 20 is connected to the first power conversion device 9 connected to the DC power supply 11 in the AC path through which the AC output is transmitted. Such a connection method is also called an AC link method.
  • another DC power supply 12 is connected to the connection point between the first power conversion device 9 and the DC power supply 11.
  • the second DC power supply 12 which is a storage battery supplies the DC power to the DC path through which the DC power of the DC power supply 11 is transmitted.
  • Such a connection method is also called a DC link method.
  • Plant control unit 10 based on the system voltage V s and the system current Is of the grid interconnection point at the output of the power converter controls a plurality of power converter 9.
  • the plant control device 10 transmits an active power command value P * , an ineffective power command value Q *, and an active power output upper limit value Pref_limit to each of the plurality of power conversion devices 9.
  • Each of the plurality of power conversion devices 9 outputs AC output power based on the active power command value P * and the active power command value Q * within a range not exceeding the active power output upper limit value Pref_limit .
  • the plant control device 10 includes a power command calculation block 10b and a high-speed frequency droop block 10a.
  • Power command calculation block 10b calculates various system parameters including the effective power P and reactive power Q and the power factor Pf and the system voltage frequency f s.
  • the power command calculation block 10b calculates the active power command value P * and the reactive power command value Q * .
  • the high-speed frequency droop block 10a calculates a pseudo-angular velocity ⁇ v and a pseudo-internal phase angle ⁇ v .
  • the pseudo-angular velocity ⁇ v is calculated by the following equation (1).
  • ⁇ v 2 ⁇ f s ... (1)
  • Frequency f s in the formula (1) is a system voltage frequency by the grid interconnection point of the renewable energy power plant system 4 (i.e. the connection point 32). That is, ⁇ v is an angular frequency obtained from the system voltage frequency f s .
  • the pseudo internal phase angle ⁇ v is calculated by the equations (2) to (5) described later. Since the phase is generally obtained by integrating the frequency or the angular frequency, the pseudo internal phase angle ⁇ v is determined based on the integrated value of the pseudo angular velocity ⁇ v also in the embodiment. Specifically, the pseudo internal phase angle ⁇ v is calculated by the equation (2) described later when the renewable energy power generation plant system 4 is in normal operation. The pseudo internal phase angle ⁇ v calculated by the equation (2) is an integrated value obtained by integrating the difference between the pseudo angular velocity ⁇ v and the rated frequency of the renewable energy power plant system 4. On the other hand, when a system voltage drop occurs, the pseudo internal phase angle ⁇ v is calculated using equations (3) to (5) described later.
  • the high-speed frequency droop block 10a outputs the active power output upper limit value Pref_limit based on the pseudo angular velocity ⁇ v and the pseudo internal phase angle ⁇ v . Specifically, in the high-speed frequency droop block 10a, when the absolute value of the pseudo internal phase angle ⁇ v is equal to or greater than a predetermined reference phase angle, if the pseudo angular velocity ⁇ v increases, the active power output upper limit value of the power conversion device is increased.
  • the active power output upper limit value Phase_limit is calculated so as to reduce the Phase_limit .
  • the case where the pseudo-angular velocity ⁇ v increases is when the system voltage frequency f s increases.
  • the synchronous generator system 3 is connected to the bus 30 via the connection point 31.
  • the synchronous generator system 3 includes a synchronous generator 3a and a generator control device 3b.
  • the generator control device 3b includes a governor 3c which is a speed governor.
  • the governor 3c is constructed so as to regulate the speed of the synchronous generator 3a by a mechanical mechanism.
  • FIG. 2 is a diagram showing a configuration of a high-speed frequency droop block 10a included in the renewable energy power generation plant system 4 according to the embodiment.
  • FIG. 3 is a time chart showing the operation of the renewable energy power generation plant system 4 according to the embodiment.
  • the block diagram of FIG. 2 is not a limited illustration of the actual hardware circuit configuration, but corresponds to a functional block diagram. That is, the high-speed frequency droop block 10a may be realized by software by executing the software program previously stored in the non-volatile memory of the plant control device 10 by the arithmetic processing unit of the plant control device 10. In this case, each block of FIG. 2 is treated as a functional block included in the plant control device 10.
  • a dedicated processing circuit in which the high-speed frequency droop block 10a is constructed in hardware may be built in the plant control device 10.
  • each block shown in FIG. 2 is constructed by a combination of circuit logic or logic gates in a dedicated processing circuit.
  • the high-speed frequency droop block 10a includes a first difference block 10a1, a multiplication block 10a2, a first-order lag element calculation block 10a3, a second difference block 10a4, an internal phase angle determination block 10a5, an internal phase angle calculation block 10a6, and the like.
  • a system voltage determination block 10a7 is provided.
  • the first difference block 10a1 outputs the difference between ⁇ v and 2 ⁇ f 0 .
  • f s is the system voltage frequency at the grid interconnection point, and is sometimes referred to as the “self-end frequency” of the renewable energy power plant system 4.
  • f 0 is the rated frequency of the system, for example, 50 Hz or 60 Hz.
  • the multiplication block 10a2 multiplies the output of the first difference block 10a1 and the output of the internal phase angle determination block 10a5.
  • the first-order lag element calculation block 10a3 performs an operation based on the first-order lag element of the gain K and the time constant T on the output of the multiplication block 10a2.
  • Second difference block 10a4 calculates the difference between the output of the primary delay element calculation block 10a3 and plant rated output P 0 of the renewable energy power plant system 4.
  • the internal phase angle determination block 10a5 outputs 1 or 0 to the multiplication block 10a2 based on the comparison determination between the absolute value of the pseudo internal phase angle ⁇ v and the internal phase angle threshold ⁇ thre .
  • the internal phase angle threshold value ⁇ thre can be set based on, for example, the inertial constant of the synchronous generator 3a and the acceleration step-out prevention function.
  • the output of the first-order lag element calculation block 10a3 is input to the second difference block 10a4 only when the absolute value of the pseudo internal phase angle ⁇ v is equal to or more than a predetermined reference (that is, ⁇ thre ). Will be done.
  • a predetermined reference that is, ⁇ thre .
  • the internal phase angle calculation block 10a6 calculates the pseudo internal phase angle ⁇ v by selectively using the equations (2) to (5) described later. Equations (2) to (5) are mounted on the high-speed frequency droop block 10a as predetermined calculation logic.
  • the system voltage determination block 10a7 is constructed so as to perform a comparative determination between the system voltage V s , the voltage drop threshold V sth, and the voltage recovery threshold V sth_r .
  • the voltage drop threshold V sth and the voltage recovery threshold V sth_r are shown in FIG. 3, and V sth ⁇ V sth_r .
  • the voltage recovery threshold value V sth_r may be set to a value of about 30% of the rated system voltage or the plant rated output P 0 as an example.
  • the voltage drop threshold V sth may be set to a value of about 10% of the rated system voltage or the plant rated output P 0 as an example.
  • System voltage determination block 10a7 is to connect the switch SW to switch the calculation logic of the internal phase angle calculation block 10a6 based on the magnitude of system voltage V s to one of the contacts A ⁇ C.
  • the system voltage determination block 10a7 connects the switch SW to the contact A when V s ⁇ V sth .
  • ⁇ v is calculated according to the equation (2).
  • the pseudo internal phase angle ⁇ v is determined by the following equation (2).
  • the system voltage determination block 10a7 When V s ⁇ V sth , the system voltage determination block 10a7 further connects the switch SW to the contact B or the contact C according to the magnitude relationship between the voltage recovery threshold value V sth_r and the system voltage V s . If the system voltage drops significantly, the pseudo-angular velocity ⁇ v may not be obtained. A typical example in which the system voltage drops significantly is a momentary voltage drop due to a system accident 50 or the like. In order to deal with such a case, the system voltage determination block 10a7 according to the embodiment is set to ⁇ in the following “first calculation method” and “second calculation method” according to the recovery status of the system voltage drop. Calculate v .
  • the ⁇ vbefore of the equation (3) is a pseudo internal phase angle ⁇ v calculated according to the above equation (2) based on the pseudo angular velocity ⁇ vbefore of the time t vbefore when the system voltage drop due to the system accident 50 occurs. That is, ⁇ vbefore is a pseudo internal phase angle ⁇ v calculated according to the equation (2) in the control step immediately before the time when V s ⁇ V sth is determined.
  • the second calculation method is as follows. After a V s ⁇ V sth, when a V s ⁇ V sth_r, the switch SW is connected to contact C. This time point (time tvafter in FIG. 3) is assumed to be the first control step after the system voltage V s rises to a voltage equal to or higher than the voltage recovery threshold value V sth_r , and is a time point when it is determined that the voltage drop has recovered. Is.
  • ⁇ v is calculated according to the following equations (4) and (5). After the voltage drop is recovered, ⁇ v can be determined based on the following equations (4) and (5).
  • ⁇ v ⁇ vapor ... (4)
  • FIG. 3 shows a system voltage drop due to the system accident 50.
  • t vbefore is the time when the system voltage drops due to the system accident 50 (also referred to as the first time t 1 ).
  • t Vafter is the time (referred to as a second time t 2) corresponding to the first control step in which the system voltage drop is determined that recovered.
  • tvreturn is the time when the system voltage starts to rise from a drop.
  • ⁇ vafter is a pseudo internal phase angle at the time t vafter at which it is determined that the system voltage drop due to the system accident 50 has recovered.
  • ⁇ vbefore is a value taken by the pseudo internal phase angle at the time t vbefore when the system voltage drop due to the system accident 50 occurs.
  • ⁇ vafter is a pseudo-angular velocity at time tvafter at which it is determined that the system voltage drop due to the system accident 50 has recovered.
  • ⁇ vbefore is a pseudo-angular velocity at time t vbefore when the system voltage drop due to the system accident 50 occurs.
  • First term on the right side of the above equation (5) is a value based on the integral of the pseudo angular speed omega v in the first time t 1 to the system voltage drop occurs.
  • the second term on the right side of the above equation (5) sets the period (t 1- t 2 ) from the first time t 1 to the second time t 2 with respect to the mean value ( ⁇ vafter + ⁇ vbefore ) / 2. It is multiplied.
  • the average value ( ⁇ vafter + ⁇ vbefore ) / 2 is the arithmetic mean value of the pseudo-angular velocity ⁇ v from the first time t 1 to the second time t 2 . Multiplying the period (t 1- t 2 ) is equivalent to performing an integral over time.
  • the voltage is remarkably lowered and the pseudo-angular velocity ⁇ v is not obtained in the blank period. Even if there is, the control using the pseudo internal phase angle ⁇ v can be continued.
  • the switch SW is returned to the contact A triggered by the recovery of the interconnection point voltage above a certain level, and the calculation formula of ⁇ v is set to the formula (2) again.
  • tvreturn is the time when the system voltage changes from decreasing to increasing.
  • tvafter is the time when the plant control device 10 actually detects the voltage recovery after tvreturn and reflects it in the control.
  • FIG. 3 schematically shows the time difference between t vretturn and t vafter , this time difference is actually extremely small.
  • the pseudo internal phase angle ⁇ v may be reset after a predetermined reset time has elapsed.
  • the reset time may be, for example, 30 seconds. This provides the ability to remove the offset.
  • the offset removal function may be stopped (locked) until a predetermined lock time elapses.
  • the lock time may be, for example, 5 minutes.
  • the plant control device 10 since the plant control device 10 includes the high-speed frequency droop block 10a, high-speed processing is possible, so that the power conversion device has a high response speed so as to suppress undesired acceleration.
  • the active power output of 9 can be reduced. Even when there is a possibility that the synchronous generator 3a may accelerate unfavorably due to a system voltage drop due to the system accident 50 according to FIGS. 1 and 3, it is possible to suppress undesired acceleration such as one-wave acceleration step-out. it can.
  • the response speed of the mechanical speed governor (governor 3c) of the synchronous generator 3a is too slow to accelerate this acceleration. It may not be suppressed. As a result, the governor 3c may not be able to suppress the one-wave acceleration detuning.
  • the high-speed frequency droop block 10a operating on the plant control device 10 can perform a high-speed response. As a result, one-wave acceleration detuning can be effectively suppressed.
  • the general governor time constant of the synchronous generator 3a is very large, about 1 second or more, and it has the effect of suppressing the accelerated step-out of the synchronous generator 3a in the event of a large-scale accident in the system. Low.
  • the plant control device 10 is equipped with the high-speed frequency droop block 10a, a high-speed control response of 50 milliseconds or less can be realized by control processing including electronic control as an example. If the output of a nearby power source is suppressed while the synchronous generator 3a is accelerating, the acceleration of the synchronous generator 3a will also be moderate.
  • the high-speed frequency droop block 10a can switch the calculation method (equations (2) to (5)) depending on the presence or absence of the system voltage decrease, the system instability due to the system voltage decrease.
  • the risk of conversion can be suppressed.
  • the gain K and the time constant T of the first-order lag element calculation block 10a3 can be set so as to sufficiently enhance the acceleration step-out prevention effect.
  • the rotation speed of the synchronous generator 3a by the high-speed governor control of the renewable energy power plant can be effectively stabilized.
  • the high-speed frequency droop block 10a controls the output of the power converter 9 by using ⁇ v and ⁇ v as input parameters to prevent one-wave acceleration detuning of the synchronous generator 3a due to a system accident or the like. Contribute to. It is possible to prevent one-wave acceleration detuning of the synchronous generator 3a in the event of a system accident without destabilizing the system during steady state.
  • the pseudo internal phase angle ⁇ v is calculated according to the above equation (2). Further, according to the embodiment, when a system voltage drop (see the system accident 50 in FIG. 3) occurs in which the system voltage V s falls below a predetermined voltage drop threshold V sth , the system voltage drop is recovered. The pseudo internal phase angle is calculated based on the equation (5). As a result, the pseudo internal phase angle ⁇ v can be calculated both during normal operation and when a voltage drop occurs.
  • FIG. 4 to 6 are graphs for explaining the effect of the renewable energy power generation plant system 4 according to the embodiment.
  • FIG. 4 shows the internal phase angle of the synchronous generator 3a.
  • FIG. 5 shows the rotation speed of the synchronous generator 3a.
  • FIG. 6 shows the output power of the power conversion device 9 (that is, the PV inverter) connected to the DC power supply 11.
  • the solid line graph is the data obtained in the embodiment, and the broken line graph is the comparative example data.
  • the comparative example data of the broken line corresponds to the data in the case where the high-speed frequency droop block 10a of the embodiment is not provided.
  • the broken line X1 in FIG. 5 exemplifies one-wave acceleration detuning.
  • the high-speed frequency droop block 10a temporarily lowers the active power output upper limit value Pref_limit , thereby locally lowering the output power of the power conversion device 9 as indicated by the arrow X2 in FIG. Can be made to.
  • the operation of the synchronous generator 3a can be stabilized.

Abstract

This renewable energy power plant system is connected to a synchronous generator with a bus line interposed. The renewable energy power plant system includes: a renewable energy power generating device; a power conversion device that converts DC power generated by the renewable energy power generating device to AC power; and a plant control device that controls the power conversion device on the basis of the power system voltage and power system current of a power system interconnection point at the output side of the power conversion device. The plant control device incudes a frequency droop block that calculates the active power output upper limit of the power conversion device. The frequency droop block calculates the pseudo angular velocity and the pseudo internal phase angle. When the absolute value of the pseudo internal phase angle is a predetermined reference phase angle or greater, the frequency droop block calculates the active power output upper limit so that the active power output upper limit is decreased if the pseudo angular velocity has increased.

Description

再生可能エネルギー発電プラントシステムおよびプラント制御装置Renewable energy power plant system and plant controller
　本出願は、再生可能エネルギー発電プラントシステムおよびプラント制御装置に関するものである。 This application relates to a renewable energy power plant system and a plant control device.
　従来、例えば日本特開２０１５―１３０７７７号公報に記載されているように、電力系統安定化装置を備えるプラントシステムが知られている。上記従来の技術の電力系統安定化装置は、系統事故時に発電機の解列および再生可能エネルギー発電装置の停止を行うように構築されている。系統事故時に発電機を解列させることで発電機の脱調を抑制でき、再生可能エネルギー発電装置を停止させることで電力系統安定化に必要な発電機の数を減らすこともできる。 Conventionally, as described in, for example, Japanese Patent Application Laid-Open No. 2015-130777, a plant system including a power system stabilizer is known. The power system stabilizer of the above-mentioned conventional technique is constructed so as to disconnect the generator and stop the renewable energy power generation device in the event of a system accident. Disengagement of generators in the event of a system accident can prevent the generators from stepping out, and stopping the renewable energy generator can reduce the number of generators required to stabilize the power system.
日本特開２０１５―１３０７７７号公報Japanese Patent Application Laid-Open No. 2015-130777
　系統事故が発生しても発電機の解列と再生可能エネルギー発電装置の停止とを行わずに制御を継続したい場合もある。系統事故時に系統電圧が瞬時低下すると、同期発電機が好ましくない加速動作をすることがある。一般的に、同期発電機にはガバナが設けられている。このガバナは、同期発電機を調速するための調速装置である。しかしながら、同期発電機に設けられる調速装置は一般的に機械的な装置であるので、応答速度が遅い。この応答速度の遅さは、例えば時定数が１秒以上などの遅さである。このような応答速度の遅さに起因して、従来の同期発電機の調速機能は、一波加速脱調などの好ましくない加速を抑制する効果が低いという問題があった。 Even if a system accident occurs, there are cases where you want to continue control without disconnecting the generator and stopping the renewable energy generator. If the system voltage drops momentarily during a system accident, the synchronous generator may perform unfavorable acceleration operation. Generally, the synchronous generator is provided with a governor. This governor is a speed governor for controlling the speed of a synchronous generator. However, since the speed governor provided in the synchronous generator is generally a mechanical device, the response speed is slow. This slow response speed is, for example, a slow time constant of 1 second or more. Due to such a slow response speed, the speed control function of the conventional synchronous generator has a problem that the effect of suppressing unfavorable acceleration such as one-wave acceleration detuning is low.
　本出願は、上述のような課題を解決するためになされたもので、高速応答可能な調速機能を搭載した再生可能エネルギー発電プラントシステムおよびプラント制御装置を提供することを目的とする。 This application was made to solve the above-mentioned problems, and an object of the present application is to provide a renewable energy power generation plant system and a plant control device equipped with a speed control function capable of high-speed response.
　本出願にかかる再生可能エネルギー発電プラントシステムは、
　昇圧用変圧器または送電線を介して同期発電機の近傍の母線と接続される再生可能エネルギー発電プラントシステムであって、
　再生可能エネルギー発電装置と、
　前記再生可能エネルギー発電装置で発電された直流電力を交流電力に変換する電力変換装置と、
　前記電力変換装置の出力側における系統連系点の系統電圧および系統電流に基づいて、前記電力変換装置を制御するプラント制御装置と、
　を含み、
　前記プラント制御装置は、前記電力変換装置の有効電力出力上限値を算出する周波数ドループブロックを含み、
　前記周波数ドループブロックは、前記系統電圧の周波数から求めた角周波数である疑似角速度と、前記疑似角速度の積分値に基づく疑似内部位相角と、を算出し、
　前記周波数ドループブロックは、前記疑似内部位相角の絶対値が予め定めた基準位相角以上であるときに、前記疑似角速度が増大したら前記有効電力出力上限値を低下させるように構築されたものである。 The renewable energy power plant system according to this application is
A renewable energy power plant system that is connected to a bus in the vicinity of a synchronous generator via a step-up transformer or transmission line.
Renewable energy generator and
A power conversion device that converts DC power generated by the renewable energy power generation device into AC power, and
A plant control device that controls the power conversion device based on the system voltage and system current of the grid interconnection point on the output side of the power conversion device.
Including
The plant control device includes a frequency droop block for calculating an active power output upper limit value of the power conversion device.
The frequency droop block calculates a pseudo-angular velocity, which is an angular frequency obtained from the frequency of the system voltage, and a pseudo-internal phase angle based on an integral value of the pseudo-angular velocity.
The frequency droop block is constructed so that when the absolute value of the pseudo internal phase angle is equal to or greater than a predetermined reference phase angle, the active power output upper limit value is lowered when the pseudo angular velocity increases. ..
　本出願にかかるプラント制御装置は、
　昇圧用変圧器または送電線を介して同期発電機の近傍の母線と接続される再生可能エネルギー発電プラントシステムに含まれる電力変換装置を制御するように構築され、前記電力変換装置は前記再生可能エネルギー発電プラントシステムが含む再生可能エネルギー発電装置で発電された直流電力を交流電力に変換するものであるプラント制御装置であって、
　プラント制御装置は、
　前記電力変換装置の出力側における系統連系点の系統電圧および系統電流に基づいて演算した電力指令値を前記電力変換装置に伝達するように構築された電力指令計算ブロックと、
　前記電力変換装置の有効電力出力上限値を算出する周波数ドループブロックと、
　を含み、
　前記周波数ドループブロックは、前記系統電圧の周波数から求めた角周波数である疑似角速度と、前記疑似角速度の積分値に基づく疑似内部位相角と、を算出し、
　前記周波数ドループブロックは、前記疑似内部位相角の絶対値が予め定めた基準位相角以上であるときに、前記疑似角速度が増大したら前記有効電力出力上限値を低下させるように構築されたものである。 The plant control device according to this application is
The power converter is constructed to control a power converter included in a renewable energy power plant system connected to a bus in the vicinity of a synchronous generator via a step-up transformer or transmission line, which power converter is said to be the renewable energy. A plant control device that converts DC power generated by a renewable energy power generation device included in a power plant system into AC power.
The plant controller
A power command calculation block constructed to transmit a power command value calculated based on the system voltage and system current of the grid interconnection point on the output side of the power converter to the power converter.
A frequency droop block that calculates the upper limit of the active power output of the power converter, and
Including
The frequency droop block calculates a pseudo-angular velocity, which is an angular frequency obtained from the frequency of the system voltage, and a pseudo-internal phase angle based on an integral value of the pseudo-angular velocity.
The frequency droop block is constructed so that when the absolute value of the pseudo internal phase angle is equal to or greater than a predetermined reference phase angle, the active power output upper limit value is lowered when the pseudo angular velocity increases. ..
　本出願によれば、プラント制御装置が周波数ドループブロックを備えることで高速処理が可能となるので、周波数ドループブロックによる調速機能を高い応答速度で差動させることができる。これにより、連系された同期発電機で好ましくない加速が発生することを抑制するように、高い応答速度で電力変換装置の有効電力出力を低下させることができる。 According to the present application, since the plant control device is provided with the frequency droop block, high-speed processing is possible, so that the speed control function by the frequency droop block can be differentiated at a high response speed. As a result, the active power output of the power converter can be reduced at a high response speed so as to suppress the occurrence of undesired acceleration in the interconnected synchronous generators.
実施の形態にかかる再生可能エネルギー発電プラントシステムの構成を示す図である。It is a figure which shows the structure of the renewable energy power generation plant system which concerns on embodiment. 実施の形態にかかる再生可能エネルギー発電プラントシステムが備える高速周波数ドループブロックの構成を示す図である。It is a figure which shows the structure of the high-speed frequency droop block provided in the renewable energy power generation plant system which concerns on embodiment. 実施の形態にかかる再生可能エネルギー発電プラントシステムの動作を示すタイムチャートである。It is a time chart which shows the operation of the renewable energy power generation plant system which concerns on embodiment. 実施の形態にかかる再生可能エネルギー発電プラントシステムの効果を説明するためのグラフである。It is a graph for demonstrating the effect of the renewable energy power generation plant system which concerns on embodiment. 実施の形態にかかる再生可能エネルギー発電プラントシステムの効果を説明するためのグラフである。It is a graph for demonstrating the effect of the renewable energy power generation plant system which concerns on embodiment. 実施の形態にかかる再生可能エネルギー発電プラントシステムの効果を説明するためのグラフである。It is a graph for demonstrating the effect of the renewable energy power generation plant system which concerns on embodiment.
　図１は、実施の形態にかかる再生可能エネルギー発電プラントシステム４の構成を示す図である。再生可能エネルギー発電プラントシステム４は、母線３０を介して同期発電機システム３と接続される。図１には、再生可能エネルギー発電プラントシステム４と同期発電機システム３とを含む系統連系電力システム１が図示されている。なお、図１の符号５０は系統事故を模式的に図示したものである。 FIG. 1 is a diagram showing a configuration of a renewable energy power generation plant system 4 according to an embodiment. The renewable energy power generation plant system 4 is connected to the synchronous generator system 3 via a bus 30. FIG. 1 illustrates a grid-connected power system 1 including a renewable energy power plant system 4 and a synchronous generator system 3. Reference numeral 50 in FIG. 1 schematically illustrates a system accident.
　同期発電機３ａと再生可能エネルギー発電プラントシステム４とが近傍において連系されていることが好ましい。ここでいう「近傍」は、地理的な意味合いよりもむしろ、電気的な距離が近いことを意味している。実施の形態では、同期発電機３ａが加速している時に再生可能エネルギー発電プラントシステム４の出力を抑制すれば同期発電機３ａの加速が緩やかになる程度に、同期発電機３ａと再生可能エネルギー発電プラントシステム４とが近傍において連系されている。「近傍」の程度は、例えば実施の形態のように同期発電機３ａと再生可能エネルギー発電プラントシステム４とが昇圧用変圧器あるいは比較的短い長さの送電線を介して同一の母線３０に接続されていることが好ましく、これらが同一の変電所内に設けられていることがさらに好ましい。 It is preferable that the synchronous generator 3a and the renewable energy power generation plant system 4 are interconnected in the vicinity. The term "neighborhood" here means that the electrical distance is short, rather than the geographical meaning. In the embodiment, if the output of the renewable energy power generation plant system 4 is suppressed when the synchronous generator 3a is accelerating, the acceleration of the synchronous generator 3a becomes moderate, and the synchronous generator 3a and the renewable energy power generation are performed. It is interconnected with the plant system 4 in the vicinity. To the extent of "nearby", for example, as in the embodiment, the synchronous generator 3a and the renewable energy power generation plant system 4 are connected to the same bus 30 via a step-up transformer or a transmission line having a relatively short length. It is more preferable that they are provided in the same substation.
　再生可能エネルギー発電プラントシステム４は、変流器７ａと、計器用変成器７ｂと、連系トランス５と、複数の開閉器６と、複数のトランス８と、複数の電力変換装置９と、複数の直流電源１１、１２と、を備えている。 The renewable energy power plant system 4 includes a current transformer 7a, an instrument transformer 7b, an interconnection transformer 5, a plurality of switches 6, a plurality of transformers 8, a plurality of power converters 9, and a plurality of transformers. The DC power supplies 11 and 12 are provided.
　図１に示すように、連系トランス５の一端は、母線３０の接続点３２に接続している。連系トランス５の他端は、複数の開閉器６それぞれの一端と接続している。複数の開閉器６それぞれの他端は、複数のトランス８それぞれの一端と接続している。複数のトランス８それぞれの他端は、複数の電力変換装置９それぞれの交流出力端に接続されている。 As shown in FIG. 1, one end of the interconnection transformer 5 is connected to the connection point 32 of the bus 30. The other end of the interconnection transformer 5 is connected to one end of each of the plurality of switches 6. The other end of each of the plurality of switches 6 is connected to one end of each of the plurality of transformers 8. The other end of each of the plurality of transformers 8 is connected to the AC output end of each of the plurality of power conversion devices 9.
　変流器７ａおよび計器用変成器７ｂの信号出力はプラント制御装置１０に伝達されている。これによりプラント制御装置１０は系統連系点の系統電流Ｉｓの値および系統電圧Ｖｓの値を計測することができる。 The signal outputs of the current transformer 7a and the instrument transformer 7b are transmitted to the plant control device 10. Thus the plant controller 10 can measure the value of the value and the system voltage V s of the system current Is of the grid interconnection point.
　直流電源１１は、再生可能エネルギー発電装置である。再生可能エネルギー発電装置は、天候によって発電量が左右される発電装置であり、太陽電池モジュールを含む太陽電池アレイであってもよく、あるいは風力発電機であってもよい。実施の形態にかかる再生可能エネルギー発電装置は、一例として太陽電池モジュールである。一方、直流電源１２は、蓄電池である。実施の形態では、直流電源１２が複数個設けられている。 The DC power supply 11 is a renewable energy power generation device. The renewable energy power generation device is a power generation device whose amount of power generation depends on the weather, and may be a solar cell array including a solar cell module or a wind power generator. The renewable energy power generation device according to the embodiment is, for example, a solar cell module. On the other hand, the DC power supply 12 is a storage battery. In the embodiment, a plurality of DC power supplies 12 are provided.
　複数の電力変換装置９は、複数の直流電源１１、１２からの直流電力を交流電力に変換する。電力変換装置９は、具体的には、複数の半導体スイッチング素子で構築された三相交流インバータ回路である。電力変換装置９は、パワーコンディショナシステム（ＰＣＳ）とも称される。 The plurality of power conversion devices 9 convert DC power from the plurality of DC power sources 11 and 12 into AC power. Specifically, the power conversion device 9 is a three-phase AC inverter circuit constructed of a plurality of semiconductor switching elements. The power converter 9 is also referred to as a power conditioner system (PCS).
　複数の電力変換装置９は、第一の電力変換装置９と第二の電力変換装置９とを含む。直流電源１１と接続している電力変換装置９を、「第一の電力変換装置９」とする。直流電源１２と接続している電力変換装置９を、「第二の電力変換装置９」とする。 The plurality of power conversion devices 9 include a first power conversion device 9 and a second power conversion device 9. The power conversion device 9 connected to the DC power supply 11 is referred to as a "first power conversion device 9". The power conversion device 9 connected to the DC power supply 12 is referred to as a "second power conversion device 9".
　実施の形態では、第二の電力変換装置９および一つの直流電源１２とで蓄電システム（Ｅｎｅｒｇｙ　Ｓｔｏｒａｇｅ　Ｓｙｓｔｅｍ：ＥＳＳ）２０が構築されている。これより、蓄電システム２０は、交流出力が伝達されるＡＣパスにおいて、直流電源１１と接続した第一の電力変換装置９に接続される。このような接続方式は、ＡＣリンク方式とも呼ばれる。 In the embodiment, the energy storage system (Energy Storage System: ESS) 20 is constructed by the second power conversion device 9 and one DC power supply 12. From this, the power storage system 20 is connected to the first power conversion device 9 connected to the DC power supply 11 in the AC path through which the AC output is transmitted. Such a connection method is also called an AC link method.
　また、実施の形態では、他の一つの直流電源１２が、第一の電力変換装置９と直流電源１１との接続点に接続されている。これにより、直流電源１１の直流電力が伝達されるＤＣパスに、蓄電池である第二の直流電源１２が直流電力を供給する。このような接続方式は、ＤＣリンク方式とも呼ばれる。 Further, in the embodiment, another DC power supply 12 is connected to the connection point between the first power conversion device 9 and the DC power supply 11. As a result, the second DC power supply 12 which is a storage battery supplies the DC power to the DC path through which the DC power of the DC power supply 11 is transmitted. Such a connection method is also called a DC link method.
　プラント制御装置１０は、電力変換装置の出力側における系統連系点の系統電圧Ｖｓおよび系統電流Ｉｓに基づいて、複数の電力変換装置９を制御する。制御パラメータとして、プラント制御装置１０は、複数の電力変換装置９それぞれに対して、有効電力指令値Ｐ＊と無効電力指令値Ｑ＊と有効電力出力上限値Ｐｒｅｆ＿ｌｉｍｉｔとを伝達する。複数の電力変換装置９それぞれは、有効電力出力上限値Ｐｒｅｆ＿ｌｉｍｉｔを超えない範囲内で、有効電力指令値Ｐ＊と無効電力指令値Ｑ＊とに基づいて交流出力電力を出力する。 Plant control unit 10 based on the system voltage V s and the system current Is of the grid interconnection point at the output of the power converter controls a plurality of power converter 9. As a control parameter, the plant control device 10 transmits an active power command value P * , an ineffective power command value Q *, and an active power output upper limit value Pref_limit to each of the plurality of power conversion devices 9. Each of the plurality of power conversion devices 9 outputs AC output power based on the active power command value P * and the active power command value Q * within a range not exceeding the active power output upper limit value Pref_limit .
　具体的には、プラント制御装置１０は、電力指令計算ブロック１０ｂと、高速周波数ドループブロック１０ａを含む。電力指令計算ブロック１０ｂは、有効電力Ｐと無効電力Ｑと力率Ｐｆと系統電圧周波数ｆｓとを含む各種系統パラメータを演算する。電力指令計算ブロック１０ｂは、有効電力指令値Ｐ＊と無効電力指令値Ｑ＊とを演算する。 Specifically, the plant control device 10 includes a power command calculation block 10b and a high-speed frequency droop block 10a. Power command calculation block 10b calculates various system parameters including the effective power P and reactive power Q and the power factor Pf and the system voltage frequency f s. The power command calculation block 10b calculates the active power command value P * and the reactive power command value Q * .
　高速周波数ドループブロック１０ａは、疑似角速度ωｖと疑似内部位相角δｖとを算出する。疑似角速度ωｖは、下記の式（１）で算出される。
　ωｖ＝２πｆｓ　　　・・・（１） The high-speed frequency droop block 10a calculates a pseudo-angular velocity ω v and a pseudo-internal phase angle δ v . The pseudo-angular velocity ω v is calculated by the following equation (1).
ω v = 2πf s ... (1)
　式（１）における周波数ｆｓは、再生可能エネルギー発電プラントシステム４の系統連系点（つまり接続点３２）における系統電圧周波数である。つまりωｖは、系統電圧周波数ｆｓから求めた角周波数である。 Frequency f s in the formula (1) is a system voltage frequency by the grid interconnection point of the renewable energy power plant system 4 (i.e. the connection point 32). That is, ω v is an angular frequency obtained from the system voltage frequency f s .
　疑似内部位相角δｖは、後述する式（２）～（５）で算出される。一般に周波数または角周波数を積分することで位相が求められるので、実施の形態においても疑似角速度ωｖの積分値に基づいて疑似内部位相角δｖが決まる。具体的には、疑似内部位相角δｖは、再生可能エネルギー発電プラントシステム４が平常運転しているときには、後述する式（２）によって算出される。式（２）で算出される疑似内部位相角δｖは、疑似角速度ωｖと再生可能エネルギー発電プラントシステム４の定格周波数との差を積分した積分値である。一方、系統電圧低下が発生した場合には、疑似内部位相角δｖは、後述する式（３）～（５）を用いて算出される。 The pseudo internal phase angle δ v is calculated by the equations (2) to (5) described later. Since the phase is generally obtained by integrating the frequency or the angular frequency, the pseudo internal phase angle δ v is determined based on the integrated value of the pseudo angular velocity ω v also in the embodiment. Specifically, the pseudo internal phase angle δ v is calculated by the equation (2) described later when the renewable energy power generation plant system 4 is in normal operation. The pseudo internal phase angle δ v calculated by the equation (2) is an integrated value obtained by integrating the difference between the pseudo angular velocity ω v and the rated frequency of the renewable energy power plant system 4. On the other hand, when a system voltage drop occurs, the pseudo internal phase angle δ v is calculated using equations (3) to (5) described later.
　高速周波数ドループブロック１０ａは、疑似角速度ωｖと疑似内部位相角δｖとに基づいて、有効電力出力上限値Ｐｒｅｆ＿ｌｉｍｉｔを出力する。具体的には、高速周波数ドループブロック１０ａは、疑似内部位相角δｖの絶対値が予め定めた基準位相角以上であるときに、疑似角速度ωｖが増大したら電力変換装置の有効電力出力上限値Ｐｒｅｆ＿ｌｉｍｉｔを低下させるように有効電力出力上限値Ｐｒｅｆ＿ｌｉｍｉｔを算出する。疑似角速度ωｖが増大する場合とは、系統電圧周波数ｆｓが増大したときである。 The high-speed frequency droop block 10a outputs the active power output upper limit value Pref_limit based on the pseudo angular velocity ω v and the pseudo internal phase angle δ v . Specifically, in the high-speed frequency droop block 10a, when the absolute value of the pseudo internal phase angle δ v is equal to or greater than a predetermined reference phase angle, if the pseudo angular velocity ω v increases, the active power output upper limit value of the power conversion device is increased. The active power output upper limit value Phase_limit is calculated so as to reduce the Phase_limit . The case where the pseudo-angular velocity ω v increases is when the system voltage frequency f s increases.
　図１に示すように、同期発電機システム３は、接続点３１を介して母線３０に接続されている。同期発電機システム３は、同期発電機３ａと、発電機制御装置３ｂと、を備える。発電機制御装置３ｂは、調速機であるガバナ３ｃを備える。ガバナ３ｃは機械的なメカニズムで同期発電機３ａを調速するように構築されている。 As shown in FIG. 1, the synchronous generator system 3 is connected to the bus 30 via the connection point 31. The synchronous generator system 3 includes a synchronous generator 3a and a generator control device 3b. The generator control device 3b includes a governor 3c which is a speed governor. The governor 3c is constructed so as to regulate the speed of the synchronous generator 3a by a mechanical mechanism.
　図２は、実施の形態にかかる再生可能エネルギー発電プラントシステム４が備える高速周波数ドループブロック１０ａの構成を示す図である。図３は、実施の形態にかかる再生可能エネルギー発電プラントシステム４の動作を示すタイムチャートである。 FIG. 2 is a diagram showing a configuration of a high-speed frequency droop block 10a included in the renewable energy power generation plant system 4 according to the embodiment. FIG. 3 is a time chart showing the operation of the renewable energy power generation plant system 4 according to the embodiment.
　図２のブロック図は、現実のハードウェア回路構成を限定的に図示したものではなく、機能ブロック図に相当している。すなわち、プラント制御装置１０が持つ不揮発性メモリに予め保存されたソフトウェアプログラムをプラント制御装置１０が持つ演算処理装置で実行することで、高速周波数ドループブロック１０ａがソフトウェア的に実現されてもよい。この場合には、図２の各ブロックはプラント制御装置１０が備える機能ブロックとして取り扱われる。 The block diagram of FIG. 2 is not a limited illustration of the actual hardware circuit configuration, but corresponds to a functional block diagram. That is, the high-speed frequency droop block 10a may be realized by software by executing the software program previously stored in the non-volatile memory of the plant control device 10 by the arithmetic processing unit of the plant control device 10. In this case, each block of FIG. 2 is treated as a functional block included in the plant control device 10.
　あるいは、他の例として、高速周波数ドループブロック１０ａがハードウェア的に構築された専用処理回路が、プラント制御装置１０に内蔵されてもよい。この場合には、図２に記載された各ブロックは、専用処理回路内の回路ロジックあるいは論理ゲートの組み合わせによって構築される。 Alternatively, as another example, a dedicated processing circuit in which the high-speed frequency droop block 10a is constructed in hardware may be built in the plant control device 10. In this case, each block shown in FIG. 2 is constructed by a combination of circuit logic or logic gates in a dedicated processing circuit.
　高速周波数ドループブロック１０ａは、第一差分ブロック１０ａ１と、乗算ブロック１０ａ２と、一次遅れ要素演算ブロック１０ａ３と、第二差分ブロック１０ａ４と、内部位相角判定ブロック１０ａ５と、内部位相角算出ブロック１０ａ６と、系統電圧判定ブロック１０ａ７と、を備える。 The high-speed frequency droop block 10a includes a first difference block 10a1, a multiplication block 10a2, a first-order lag element calculation block 10a3, a second difference block 10a4, an internal phase angle determination block 10a5, an internal phase angle calculation block 10a6, and the like. A system voltage determination block 10a7 is provided.
　第一差分ブロック１０ａ１は、ωｖと２πｆ０との差分を出力する。ωｖは、ωｖ＝２πｆｓに基づいて算出される。ｆｓは系統連系点における系統電圧周波数であり、再生可能エネルギー発電プラントシステム４の「自端周波数」と称されることもある。ｆ０は、系統の定格周波数であり、一例として５０Ｈｚまたは６０Ｈｚである。 The first difference block 10a1 outputs the difference between ω v and 2πf 0 . ω v is calculated based on ω v = 2πf s . f s is the system voltage frequency at the grid interconnection point, and is sometimes referred to as the “self-end frequency” of the renewable energy power plant system 4. f 0 is the rated frequency of the system, for example, 50 Hz or 60 Hz.
　乗算ブロック１０ａ２は、第一差分ブロック１０ａ１の出力と内部位相角判定ブロック１０ａ５の出力とを乗算する。 The multiplication block 10a2 multiplies the output of the first difference block 10a1 and the output of the internal phase angle determination block 10a5.
　一次遅れ要素演算ブロック１０ａ３は、乗算ブロック１０ａ２の出力に対して、ゲインＫおよび時定数Ｔの一次遅れ要素に基づく演算を施す。 The first-order lag element calculation block 10a3 performs an operation based on the first-order lag element of the gain K and the time constant T on the output of the multiplication block 10a2.
　第二差分ブロック１０ａ４は、一次遅れ要素演算ブロック１０ａ３の出力と再生可能エネルギー発電プラントシステム４のプラント定格出力Ｐ０との差分を演算する。 Second difference block 10a4 calculates the difference between the output of the primary delay element calculation block 10a3 and plant rated output P 0 of the renewable energy power plant system 4.
　内部位相角判定ブロック１０ａ５は、疑似内部位相角δｖの絶対値と内部位相角閾値δｔｈｒｅとの比較判定に基づいて、１または０を乗算ブロック１０ａ２へと出力する。内部位相角閾値δｔｈｒｅは、例えば同期発電機３ａの慣性定数と加速脱調防止機能とに基づいて設定することができる。 The internal phase angle determination block 10a5 outputs 1 or 0 to the multiplication block 10a2 based on the comparison determination between the absolute value of the pseudo internal phase angle δ v and the internal phase angle threshold δ thre . The internal phase angle threshold value δthre can be set based on, for example, the inertial constant of the synchronous generator 3a and the acceleration step-out prevention function.
　図２にも記載したように、｜δｖ｜の値がδｔｈｒｅよりも小さいときには０が出力され、｜δｖ｜の値がδｔｈｒｅ以上であるときには１が出力される。０が出力されると乗算ブロック１０ａ２の出力はゼロとなる。１が出力されると乗算ブロック１０ａ２を通過して第一差分ブロック１０ａ１の出力が一次遅れ要素演算ブロック１０ａ３に入力される。 As described in FIG. 2, | δ v | 0 is output when the value is less than δ thre, | 1 is outputted when it is the value [delta] thre than | [delta] v. When 0 is output, the output of the multiplication block 10a2 becomes zero. When 1 is output, it passes through the multiplication block 10a2 and the output of the first difference block 10a1 is input to the first-order lag element calculation block 10a3.
　このような仕組みによれば、疑似内部位相角δｖの絶対値が予め定めた基準（つまりδｔｈｒｅ）以上である場合に限り、一次遅れ要素演算ブロック１０ａ３の出力が第二差分ブロック１０ａ４に入力される。その結果、第二差分ブロック１０ａ４において、一次遅れ要素演算ブロック１０ａ３の出力をプラント定格出力Ｐ０から減算する減算補正が施される。この減算補正が行われることで、有効電力出力上限値Ｐｒｅｆ＿ｌｉｍｉｔを低下させることができる。一方、疑似内部位相角δｖの絶対値が予め定めた基準（つまりδｔｈｒｅ）よりも小さいときには、そのような減算補正は行われず、プラント定格出力Ｐ０が有効電力出力上限値Ｐｒｅｆ＿ｌｉｍｉｔとして出力される。 According to such a mechanism, the output of the first-order lag element calculation block 10a3 is input to the second difference block 10a4 only when the absolute value of the pseudo internal phase angle δ v is equal to or more than a predetermined reference (that is, δ thre ). Will be done. As a result, in the second difference block 10a4, subtraction correction for subtracting the output of the primary delay element calculation block 10a3 from the plant rated output P 0 is performed. By performing this subtraction correction, the active power output upper limit value Pref_limit can be lowered. On the other hand, when the absolute value of the pseudo internal phase angle δ v is smaller than the predetermined reference (that is, δ thre ), such subtraction correction is not performed, and the plant rated output P 0 is output as the active power output upper limit value Pref_limit. Will be done.
　内部位相角算出ブロック１０ａ６は、後述する式（２）～（５）を選択的に使用することで疑似内部位相角δｖを算出する。式（２）～（５）は、予め定められた計算ロジックとして高速周波数ドループブロック１０ａに搭載されている。 The internal phase angle calculation block 10a6 calculates the pseudo internal phase angle δ v by selectively using the equations (2) to (5) described later. Equations (2) to (5) are mounted on the high-speed frequency droop block 10a as predetermined calculation logic.
　系統電圧判定ブロック１０ａ７は、系統電圧Ｖｓと電圧低下閾値Ｖｓｔｈと電圧回復閾値Ｖｓｔｈ＿ｒとの比較判定を行うように構築されている。電圧低下閾値Ｖｓｔｈと電圧回復閾値Ｖｓｔｈ＿ｒは図３に図示されており、Ｖｓｔｈ＜Ｖｓｔｈ＿ｒである。電圧回復閾値Ｖｓｔｈ＿ｒは一例として定格系統電圧またはプラント定格出力Ｐ０の３０％程度の値とされてもよい。電圧低下閾値Ｖｓｔｈは、一例として定格系統電圧またはプラント定格出力Ｐ０の１０％程度の値とされてもよい。 The system voltage determination block 10a7 is constructed so as to perform a comparative determination between the system voltage V s , the voltage drop threshold V sth, and the voltage recovery threshold V sth_r . The voltage drop threshold V sth and the voltage recovery threshold V sth_r are shown in FIG. 3, and V sth <V sth_r . The voltage recovery threshold value V sth_r may be set to a value of about 30% of the rated system voltage or the plant rated output P 0 as an example. The voltage drop threshold V sth may be set to a value of about 10% of the rated system voltage or the plant rated output P 0 as an example.
　系統電圧判定ブロック１０ａ７は、系統電圧Ｖｓの大きさに基づいて内部位相角算出ブロック１０ａ６の計算ロジックを切り替えるようにスイッチＳＷを接点Ａ～Ｃのいずれか一つに接続させる。 System voltage determination block 10a7 is to connect the switch SW to switch the calculation logic of the internal phase angle calculation block 10a6 based on the magnitude of system voltage V s to one of the contacts A ~ C.
　系統電圧判定ブロック１０ａ７は、Ｖｓ≧Ｖｓｔｈであるときには接点ＡにスイッチＳＷを接続させる。接点Ａへの接続により、式（２）に従ってδｖが算出される。疑似内部位相角δｖは下記の式（２）で決まる。 The system voltage determination block 10a7 connects the switch SW to the contact A when V s ≧ V sth . By connecting to the contact A, δ v is calculated according to the equation (2). The pseudo internal phase angle δ v is determined by the following equation (2).
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000002
　系統電圧判定ブロック１０ａ７は、Ｖｓ＜Ｖｓｔｈであるときには、さらに電圧回復閾値Ｖｓｔｈ＿ｒと系統電圧Ｖｓとの大小関係に応じて接点Ｂまたは接点ＣにスイッチＳＷを接続させる。系統電圧が著しく低下すると疑似角速度ωｖが得られないときがある。系統電圧が著しく低下する典型例は、系統事故５０などに伴う瞬時的な電圧低下である。そのような場合に対処するために、実施の形態にかかる系統電圧判定ブロック１０ａ７は、系統電圧低下の回復状況に応じて、次の「第一演算方法」と「第二演算方法」とでδｖを算出する。 When V s <V sth , the system voltage determination block 10a7 further connects the switch SW to the contact B or the contact C according to the magnitude relationship between the voltage recovery threshold value V sth_r and the system voltage V s . If the system voltage drops significantly, the pseudo-angular velocity ω v may not be obtained. A typical example in which the system voltage drops significantly is a momentary voltage drop due to a system accident 50 or the like. In order to deal with such a case, the system voltage determination block 10a7 according to the embodiment is set to δ in the following “first calculation method” and “second calculation method” according to the recovery status of the system voltage drop. Calculate v .
（第一演算方法）
　第一演算方法は、次のとおりである。Ｖｓ＜Ｖｓｔｈとなった後に、Ｖｓ＜Ｖｓｔｈ＿ｒである場合には、スイッチＳＷが接点Ｂに接続される。この時点では、系統電圧Ｖｓが電圧回復閾値Ｖｓｔｈ＿ｒに達するほどに回復しておらず、電圧低下がいまだ回復には至っていない。電圧低下が回復する前は、接点Ｂへの接続により下記の式（３）に従ってδｖが算出される。
　δｖ＝δｖｂｅｆｏｒｅ　　・・・（３） (First calculation method)
The first calculation method is as follows. After a V s <V sth, in the case of V s <V sth_r, the switch SW is connected to contact B. At this point, the system voltage V s has not recovered to the extent that it reaches the voltage recovery threshold V sth_r , and the voltage drop has not yet recovered. Before the voltage drop recovers, δ v is calculated according to the following equation (3) by connecting to the contact B.
δ v = δ v before ... (3)
　式（３）のδｖｂｅｆｏｒｅは、系統事故５０による系統電圧低下が発生した時刻ｔｖｂｅｆｏｒｅの疑似角速度ωｖｂｅｆｏｒｅに基づいて、上記の式（２）に従って算出された疑似内部位相角δｖである。すなわち、δｖｂｅｆｏｒｅは、Ｖｓ＜Ｖｓｔｈが判定された時刻の直前の制御ステップにおいて式（２）に従って算出された疑似内部位相角δｖである。 The δ vbefore of the equation (3) is a pseudo internal phase angle δ v calculated according to the above equation (2) based on the pseudo angular velocity ω vbefore of the time t vbefore when the system voltage drop due to the system accident 50 occurs. That is, δ vbefore is a pseudo internal phase angle δ v calculated according to the equation (2) in the control step immediately before the time when V s <V sth is determined.
（第二演算方法）
　一方、第二演算方法は、次のとおりである。Ｖｓ＜Ｖｓｔｈとなった後に、Ｖｓ≧Ｖｓｔｈ＿ｒとなった場合には、スイッチＳＷが接点Ｃに接続される。この時点（図３の時刻ｔｖａｆｔｅｒ）は、系統電圧Ｖｓが電圧回復閾値Ｖｓｔｈ＿ｒ以上の電圧に上昇した後の最初の制御ステップであるものとし、電圧低下が回復したことが判定された時点である。接点Ｃへの接続により、下記の式（４）および式（５）に従ってδｖが算出される。電圧低下が回復した後であれば、下記の式（４）および式（５）に基づいてδｖを決定することができる。
　δｖ＝δｖａｆｔｅｒ　　・・・（４） (Second calculation method)
On the other hand, the second calculation method is as follows. After a V s <V sth, when a V s ≧ V sth_r, the switch SW is connected to contact C. This time point (time tvafter in FIG. 3) is assumed to be the first control step after the system voltage V s rises to a voltage equal to or higher than the voltage recovery threshold value V sth_r , and is a time point when it is determined that the voltage drop has recovered. Is. By connecting to the contact C, δ v is calculated according to the following equations (4) and (5). After the voltage drop is recovered, δ v can be determined based on the following equations (4) and (5).
δ v = δ vapor ... (4)
Figure JPOXMLDOC01-appb-M000003
Figure JPOXMLDOC01-appb-M000003
　式（４）および式（５）における各記号の意味は下記のとおりである。図３には、系統事故５０による系統電圧低下が図示されている。図３に示すように、ｔｖｂｅｆｏｒｅは系統事故５０による系統電圧低下が発生した時刻（第一時刻ｔ１とも称す）である。ｔｖａｆｔｅｒはその系統電圧低下が回復したことが判定された最初の制御ステップに対応する時刻（第二時刻ｔ２とも称す）である。ｔｖｒｅｔｕｒｎは系統電圧が低下から上昇に転じた時刻である。 The meanings of the symbols in the formulas (4) and (5) are as follows. FIG. 3 shows a system voltage drop due to the system accident 50. As shown in FIG. 3, t vbefore is the time when the system voltage drops due to the system accident 50 (also referred to as the first time t 1 ). t Vafter is the time (referred to as a second time t 2) corresponding to the first control step in which the system voltage drop is determined that recovered. tvreturn is the time when the system voltage starts to rise from a drop.
　δｖａｆｔｅｒは、系統事故５０による系統電圧低下が回復したことが判定された時刻ｔｖａｆｔｅｒにおける疑似内部位相角である。δｖｂｅｆｏｒｅは、上記の式（３）で説明したとおり、系統事故５０による系統電圧低下が発生した時刻ｔｖｂｅｆｏｒｅに疑似内部位相角が取っていた値である。 δ vafter is a pseudo internal phase angle at the time t vafter at which it is determined that the system voltage drop due to the system accident 50 has recovered. As described in the above equation (3), δ vbefore is a value taken by the pseudo internal phase angle at the time t vbefore when the system voltage drop due to the system accident 50 occurs.
　ωｖａｆｔｅｒは、系統事故５０による系統電圧低下が回復したと判定された時刻ｔｖａｆｔｅｒの疑似角速度である。ωｖｂｅｆｏｒｅは、系統事故５０による系統電圧低下が発生した時刻ｔｖｂｅｆｏｒｅの疑似角速度である。 ωvafter is a pseudo-angular velocity at time tvafter at which it is determined that the system voltage drop due to the system accident 50 has recovered. ω vbefore is a pseudo-angular velocity at time t vbefore when the system voltage drop due to the system accident 50 occurs.
　上記の式（５）の右辺第一項は、系統電圧低下が発生した第一時刻ｔ１における疑似角速度ωｖの積分に基づく値である。上記の式（５）の右辺第二項は、平均値（ωｖａｆｔｅｒ＋ωｖｂｅｆｏｒｅ）／２に対して、第一時刻ｔ１から前記第二時刻ｔ２までの期間（ｔ１－ｔ２）を乗じたものである。平均値（ωｖａｆｔｅｒ＋ωｖｂｅｆｏｒｅ）／２は、第一時刻ｔ１から第二時刻ｔ２までの疑似角速度ωｖの算術平均値である。期間（ｔ１－ｔ２）を乗じることは、時間による積分を行うことに相当する。 First term on the right side of the above equation (5) is a value based on the integral of the pseudo angular speed omega v in the first time t 1 to the system voltage drop occurs. The second term on the right side of the above equation (5) sets the period (t 1- t 2 ) from the first time t 1 to the second time t 2 with respect to the mean value (ω vafter + ω vbefore ) / 2. It is multiplied. The average value (ω vafter + ω vbefore ) / 2 is the arithmetic mean value of the pseudo-angular velocity ω v from the first time t 1 to the second time t 2 . Multiplying the period (t 1- t 2 ) is equivalent to performing an integral over time.
　以上説明したように、実施の形態によれば、系統電圧状況に応じて式（２）～式（５）を切り替えることで、電圧が著しく低下して疑似角速度ωｖが得られなかった空白期間があっても、疑似内部位相角δｖを利用した制御を継続することができる。 As described above, according to the embodiment, by switching the equations (2) to (5) according to the system voltage condition, the voltage is remarkably lowered and the pseudo-angular velocity ω v is not obtained in the blank period. Even if there is, the control using the pseudo internal phase angle δ v can be continued.
　その後、図３に示すように、一定以上の連系点電圧回復をトリガーとしてスイッチＳＷが接点Ａに戻され、再びδｖの算出式が式（２）に設定される。 After that, as shown in FIG. 3, the switch SW is returned to the contact A triggered by the recovery of the interconnection point voltage above a certain level, and the calculation formula of δ v is set to the formula (2) again.
　なお、図３に示すように、ｔｖｒｅｔｕｒｎは系統電圧が低下から上昇に転じた時刻である。これに対し、ｔｖａｆｔｅｒはｔｖｒｅｔｕｒｎの後に実際にプラント制御装置１０が電圧回復を検知して制御に反映する時刻である。図３ではｔｖｒｅｔｕｒｎとｔｖａｆｔｅｒとの時間差を模式的に示しているが、この時間差は実際には極微小である。 As shown in FIG. 3, tvreturn is the time when the system voltage changes from decreasing to increasing. On the other hand, tvafter is the time when the plant control device 10 actually detects the voltage recovery after tvreturn and reflects it in the control. Although FIG. 3 schematically shows the time difference between t vretturn and t vafter , this time difference is actually extremely small.
　なお、疑似内部位相角δｖは、予め定めたリセット時間が経過するとリセットされてもよい。リセット時間は例えば３０秒であってもよい。これによりオフセットを除去する機能が提供される。一方、高速周波数ドループブロック１０ａの制御が効いているときには、予め定められたロック時間が経過するまでオフセット除去機能が停止（ロック）されてもよい。ロック時間は、例えば５分間であってもよい。 The pseudo internal phase angle δ v may be reset after a predetermined reset time has elapsed. The reset time may be, for example, 30 seconds. This provides the ability to remove the offset. On the other hand, when the control of the high-speed frequency droop block 10a is effective, the offset removal function may be stopped (locked) until a predetermined lock time elapses. The lock time may be, for example, 5 minutes.
　以上説明したように、実施の形態によれば、プラント制御装置１０が高速周波数ドループブロック１０ａを備えることで高速処理が可能となるので、好ましくない加速を抑制するように高い応答速度で電力変換装置９の有効電力出力を低下させることができる。図１および図３にかかる系統事故５０による系統電圧低下に起因して同期発電機３ａが好ましくない加速をする可能性がある場合でも、一波加速脱調などの好ましくない加速を抑制することができる。 As described above, according to the embodiment, since the plant control device 10 includes the high-speed frequency droop block 10a, high-speed processing is possible, so that the power conversion device has a high response speed so as to suppress undesired acceleration. The active power output of 9 can be reduced. Even when there is a possibility that the synchronous generator 3a may accelerate unfavorably due to a system voltage drop due to the system accident 50 according to FIGS. 1 and 3, it is possible to suppress undesired acceleration such as one-wave acceleration step-out. it can.
　すなわち、系統事故５０による系統電圧低下に起因して同期発電機３ａが好ましくない加速をするときに、同期発電機３ａの機械的調速機（ガバナ３ｃ）では応答速度が遅すぎてこの加速を抑制できない可能性がある。その結果、ガバナ３ｃでは一波加速脱調を抑制しきれない可能性がある。この点、実施の形態によれば、プラント制御装置１０上で作動する高速周波数ドループブロック１０ａが高速応答を行うことができる。これにより一波加速脱調を効果的に抑制することができる。 That is, when the synchronous generator 3a accelerates unfavorably due to the system voltage drop due to the system accident 50, the response speed of the mechanical speed governor (governor 3c) of the synchronous generator 3a is too slow to accelerate this acceleration. It may not be suppressed. As a result, the governor 3c may not be able to suppress the one-wave acceleration detuning. In this regard, according to the embodiment, the high-speed frequency droop block 10a operating on the plant control device 10 can perform a high-speed response. As a result, one-wave acceleration detuning can be effectively suppressed.
　より詳しく説明すると、同期発電機３ａの一般的なガバナ時定数は１秒以上程度と非常に大きく、系統で大規模な事故が発生した場合の同期発電機３ａの加速脱調を抑制する効果が低い。これに対しプラント制御装置１０に高速周波数ドループブロック１０ａを搭載すれば、電子制御を含む制御処理によって、一例として５０ミリ秒以下の高速な制御応答が実現される。同期発電機３ａが加速している時に近傍の電源の出力を抑制すれば同期発電機３ａの加速も緩やかになる。しかし、加速脱調防止効果を高めるようなゲインＫおよび時定数Ｔを設定した場合は、系統電圧低下が発生したときに系統不安定化を招くリスクがあった。その一方で、系統電圧低下による系統不安定化を防ぐようなゲインＫおよび時定数Ｔを設定した場合には、制御効果が鈍化してしまうという相反があった。既存技術はこの相反に対する課題の認識が無くその解決技術も提示されていなかったので、加速脱調防止と電圧低下対策とを両立することができないという問題があった。 More specifically, the general governor time constant of the synchronous generator 3a is very large, about 1 second or more, and it has the effect of suppressing the accelerated step-out of the synchronous generator 3a in the event of a large-scale accident in the system. Low. On the other hand, if the plant control device 10 is equipped with the high-speed frequency droop block 10a, a high-speed control response of 50 milliseconds or less can be realized by control processing including electronic control as an example. If the output of a nearby power source is suppressed while the synchronous generator 3a is accelerating, the acceleration of the synchronous generator 3a will also be moderate. However, when the gain K and the time constant T that enhance the acceleration step-out prevention effect are set, there is a risk of causing system instability when a system voltage drop occurs. On the other hand, when the gain K and the time constant T are set so as to prevent the system instability due to the system voltage drop, there is a conflict that the control effect is slowed down. Since the existing technology did not recognize the problem of this conflict and the solution technology was not presented, there was a problem that it was not possible to achieve both acceleration step-out prevention and voltage drop countermeasures.
　この点、実施の形態によれば、系統電圧低下の有無に応じて高速周波数ドループブロック１０ａが演算方法（式（２）～（５））を切り替えることができるので、系統電圧低下による系統不安定化リスクを抑制することができる。この系統不安定化リスク抑制機能を搭載することで、加速脱調防止効果を十分に高めるように一次遅れ要素演算ブロック１０ａ３のゲインＫおよび時定数Ｔを設定することができる。その結果、再生可能エネルギー発電プラントの高速ガバナ制御による同期発電機３ａの回転速度を効果的に安定化させることができる。 In this regard, according to the embodiment, since the high-speed frequency droop block 10a can switch the calculation method (equations (2) to (5)) depending on the presence or absence of the system voltage decrease, the system instability due to the system voltage decrease. The risk of conversion can be suppressed. By installing this system instability risk suppression function, the gain K and the time constant T of the first-order lag element calculation block 10a3 can be set so as to sufficiently enhance the acceleration step-out prevention effect. As a result, the rotation speed of the synchronous generator 3a by the high-speed governor control of the renewable energy power plant can be effectively stabilized.
　実施の形態によれば、同期発電機３ａの近傍に連系された分散形電源である再生可能エネルギー発電プラントシステム４が、疑似角速度ωｖ＝２πｆｓと疑似内部位相角δｖとを算出する。高速周波数ドループブロック１０ａは、ωｖとδｖとを入力パラメータとして電力変換装置９の出力を抑制する制御を行うことで、系統事故等に起因する同期発電機３ａの一波加速脱調の防止に寄与する。定常時に系統を不安定化させることなく、系統事故時の同期発電機３ａの一波加速脱調を防止することが出来る。 According to the embodiment, in the vicinity of the synchronous generator 3a is a interconnection has been distributed power renewable power plant system 4 calculates a pseudo angular speed ω v = 2πf s and the pseudo internal phase angle [delta] v .. The high-speed frequency droop block 10a controls the output of the power converter 9 by using ω v and δ v as input parameters to prevent one-wave acceleration detuning of the synchronous generator 3a due to a system accident or the like. Contribute to. It is possible to prevent one-wave acceleration detuning of the synchronous generator 3a in the event of a system accident without destabilizing the system during steady state.
　実施の形態によれば、系統電圧Ｖｓが予め定めた電圧低下閾値Ｖｓｔｈを下回らない平常運転中には、上記の式（２）に従って、疑似内部位相角δｖが算出される。また、実施の形態によれば、系統電圧Ｖｓが予め定めた電圧低下閾値Ｖｓｔｈを下回る系統電圧低下（図３の系統事故５０参照）が発生した場合に、系統電圧低下が回復した後の疑似内部位相角が、式（５）に基づいて算出される。これにより、平常運転中と電圧低下発生時との両方において疑似内部位相角δｖを算出することができる。 According to the embodiment, during normal operation in which the system voltage V s does not fall below the predetermined voltage drop threshold V sth , the pseudo internal phase angle δ v is calculated according to the above equation (2). Further, according to the embodiment, when a system voltage drop (see the system accident 50 in FIG. 3) occurs in which the system voltage V s falls below a predetermined voltage drop threshold V sth , the system voltage drop is recovered. The pseudo internal phase angle is calculated based on the equation (5). As a result, the pseudo internal phase angle δ v can be calculated both during normal operation and when a voltage drop occurs.
　実施の形態によれば、系統電圧Ｖｓが予め定めた電圧低下閾値Ｖｓｔｈを下回る系統電圧低下（図３の系統事故５０参照）が発生した場合に、系統電圧低下の発生後から系統電圧低下が回復するまでの期間は、系統電圧Ｖｓが電圧低下閾値Ｖｓｔｈを下回った時の疑似内部位相角が保持される。 According to the embodiment, when a system voltage drop (see system accident 50 in FIG. 3) occurs in which the system voltage V s falls below a predetermined voltage drop threshold V sth , the system voltage drops after the system voltage drop occurs. There time to recover, the pseudo internal phase angle when the system voltage V s falls below the brownout threshold V sth is maintained.
　図４～図６は、実施の形態にかかる再生可能エネルギー発電プラントシステム４の効果を説明するためのグラフである。図４は、同期発電機３ａの内部位相角を表している。図５は、同期発電機３ａの回転速度を表している。図６は、直流電源１１に接続された電力変換装置９（つまりＰＶインバータ）の出力電力を表している。 4 to 6 are graphs for explaining the effect of the renewable energy power generation plant system 4 according to the embodiment. FIG. 4 shows the internal phase angle of the synchronous generator 3a. FIG. 5 shows the rotation speed of the synchronous generator 3a. FIG. 6 shows the output power of the power conversion device 9 (that is, the PV inverter) connected to the DC power supply 11.
　図４～図５において、実線グラフが実施の形態で得られたデータであり、破線グラフは比較例データである。破線の比較例データは、実施の形態の高速周波数ドループブロック１０ａを備えない場合のデータに相当している。図５の破線Ｘ１は一波加速脱調を例示したものである。 In FIGS. 4 to 5, the solid line graph is the data obtained in the embodiment, and the broken line graph is the comparative example data. The comparative example data of the broken line corresponds to the data in the case where the high-speed frequency droop block 10a of the embodiment is not provided. The broken line X1 in FIG. 5 exemplifies one-wave acceleration detuning.
　実施の形態によれば、高速周波数ドループブロック１０ａが有効電力出力上限値Ｐｒｅｆ＿ｌｉｍｉｔを一時的に低下させることで、図６の矢印Ｘ２が指し示すように電力変換装置９の出力電力を局所的に低下させることができる。その結果、図４および図５の実線グラフで示すように、同期発電機３ａの動作を安定化させることができる。 According to the embodiment, the high-speed frequency droop block 10a temporarily lowers the active power output upper limit value Pref_limit , thereby locally lowering the output power of the power conversion device 9 as indicated by the arrow X2 in FIG. Can be made to. As a result, as shown by the solid line graphs of FIGS. 4 and 5, the operation of the synchronous generator 3a can be stabilized.
１　系統連系電力システム、３　同期発電機システム、３ａ　同期発電機、３ｂ　発電機制御装置、３ｃ　ガバナ、４　再生可能エネルギー発電プラントシステム、５　連系トランス、６　開閉器、７ａ　変流器、７ｂ　計器用変成器、８　トランス、９　電力変換装置、１０　プラント制御装置、１０ａ　高速周波数ドループブロック、１０ａ１　第一差分ブロック、１０ａ２　乗算ブロック、１０ａ３　一次遅れ要素演算ブロック、１０ａ４　第二差分ブロック、１０ａ５　内部位相角判定ブロック、１０ａ６　内部位相角算出ブロック、１０ａ７　系統電圧判定ブロック、１０ｂ　電力指令計算ブロック、１１　直流電源（太陽電池モジュール）、１２　直流電源（蓄電池）、２０　蓄電システム、３０　母線、３１、３２　接続点、５０　系統事故、ｆｓ　系統電圧周波数、Ｉｓ　系統電流、Ｐ　有効電力、Ｐ＊　有効電力指令値、Ｐ０　プラント定格出力、Ｐｒｅｆ＿ｌｉｍｉｔ　有効電力出力上限値、Ｑ＊　無効電力指令値、ＳＷ　スイッチ、Ｖｓ　系統電圧、Ｖｓｔｈ　電圧低下閾値、Ｖｓｔｈ＿ｒ　電圧回復閾値、δｔｈｒｅ　内部位相角閾値、ωｖ　疑似角速度、δｖ　疑似内部位相角 1 grid interconnection power system, 3 synchronous generator system, 3a synchronous generator, 3b generator control device, 3c governor, 4 renewable energy power generation plant system, 5 interconnection transformer, 6 switch, 7a converter, 7b Instrument transformer, 8 transformer, 9 power converter, 10 plant controller, 10a high-speed frequency droop block, 10a1 first difference block, 10a2 multiplication block, 10a3 first-order lag element calculation block, 10a4 second difference block, 10a5 internal phase Angle determination block, 10a6 internal phase angle calculation block, 10a7 system voltage determination block, 10b power command calculation block, 11 DC power supply (solar cell module), 12 DC power supply (storage battery), 20 power storage system, 30 bus, 31, 32 connection Point, 50 system accident, fs system voltage frequency, Is system current, P active power, P * active power command value, P 0 plant rated output, Pref_limit active power output upper limit, Q * invalid power command value, SW switch, V s system voltage, V sth voltage drop threshold, V sth_r voltage recovery threshold, δ thre internal phase angle threshold, ω v pseudo-angle velocity, δ v pseudo internal phase angle

Claims (6)

  1. 　昇圧用変圧器または送電線を介して同期発電機の近傍の母線と接続される再生可能エネルギー発電プラントシステムであって、
    　再生可能エネルギー発電装置と、
    　前記再生可能エネルギー発電装置で発電された直流電力を交流電力に変換する電力変換装置と、
    　前記電力変換装置の出力側における系統連系点の系統電圧および系統電流に基づいて、前記電力変換装置を制御するプラント制御装置と、
    　を含み、
    　前記プラント制御装置は、前記電力変換装置の有効電力出力上限値を算出する周波数ドループブロックを含み、
    　前記周波数ドループブロックは、前記系統電圧の周波数から求めた角周波数である疑似角速度と、前記疑似角速度の積分値に基づく疑似内部位相角と、を算出し、
    　前記周波数ドループブロックは、前記疑似内部位相角の絶対値が予め定めた基準位相角以上であるときに、前記疑似角速度が増大したら前記有効電力出力上限値を低下させるように構築された再生可能エネルギー発電プラントシステム。     A renewable energy power plant system that is connected to a bus in the vicinity of a synchronous generator via a step-up transformer or transmission line.
    Renewable energy generator and
    A power conversion device that converts DC power generated by the renewable energy power generation device into AC power, and
    A plant control device that controls the power conversion device based on the system voltage and system current of the grid interconnection point on the output side of the power conversion device.
    Including
    The plant control device includes a frequency droop block for calculating an active power output upper limit value of the power conversion device.
    The frequency droop block calculates a pseudo-angular velocity, which is an angular frequency obtained from the frequency of the system voltage, and a pseudo-internal phase angle based on an integral value of the pseudo-angular velocity.
    The frequency droop block is a renewable energy constructed so that when the absolute value of the pseudo internal phase angle is equal to or higher than a predetermined reference phase angle, the active power output upper limit value is lowered when the pseudo angular velocity increases. Power plant system.
  2. 　前記周波数ドループブロックは、前記系統電圧が予め定めた電圧低下閾値を下回らない場合には、前記疑似角速度の前記積分値に基づく値を前記疑似内部位相角として算出し、
    　前記周波数ドループブロックは、前記系統電圧が前記電圧低下閾値を下回る系統電圧低下が発生した場合には、前記系統電圧低下が回復した後の前記疑似内部位相角を、第一の値と第二の値との合計値に基づいて算出し、
    　前記第一の値は、前記系統電圧低下が発生した第一時刻における前記疑似角速度の積分に基づいて求められ、
    　前記第二の値は、前記第一時刻と前記系統電圧低下が回復したことが判定された第二時刻との間の前記疑似角速度の平均値を前記第一時刻と前記第二時刻との間の期間で積分することで求められる請求項１に記載の再生可能エネルギー発電プラントシステム。     When the system voltage does not fall below a predetermined voltage drop threshold value, the frequency droop block calculates a value based on the integral value of the pseudo-angular velocity as the pseudo-internal phase angle.
    When the system voltage drops below the voltage drop threshold, the frequency droop block sets the pseudo internal phase angle after the system voltage drop is recovered as the first value and the second value. Calculated based on the total value with the value,
    The first value is obtained based on the integral of the pseudo-angular velocity at the first time when the system voltage drop occurs.
    The second value is an average value of the pseudo-angular velocities between the first time and the second time when it is determined that the system voltage drop has recovered, and is between the first time and the second time. The renewable energy power plant system according to claim 1, which is obtained by integrating in the period of.
  3. 　前記合計値に相当するδｖａｆｔｅｒは、
    Figure JPOXMLDOC01-appb-I000001
    　　に従って算出され、上記式の右辺第一項が前記第一の値に相当し、上記式の右辺第二項が前記第二の値に相当し、
    　ｔｖｂｅｆｏｒｅは前記系統電圧低下が発生した前記第一時刻であり、
    　ｔｖａｆｔｅｒは前記系統電圧低下が回復したことが判定された前記第二時刻であり、
    　δｖａｆｔｅｒは、前記系統電圧低下が回復したことが判定された時刻ｔｖａｆｔｅｒにおける前記疑似内部位相角であり、
    　δｖｂｅｆｏｒｅは、前記系統電圧低下が発生した時刻ｔｖｂｅｆｏｒｅにおける前記疑似内部位相角であり、
    　ωｖａｆｔｅｒは、前記系統電圧低下が回復したと判定された時刻ｔｖａｆｔｅｒの前記疑似角速度であり、
    　ωｖｂｅｆｏｒｅは、前記系統電圧低下が発生した時刻ｔｖｂｅｆｏｒｅの前記疑似角速度である請求項２に記載の再生可能エネルギー発電プラントシステム。     The δ buffer corresponding to the total value is
    Figure JPOXMLDOC01-appb-I000001
    The first term on the right side of the above equation corresponds to the first value, and the second term on the right side of the above equation corresponds to the second value.
    t vbefore is the first time when the system voltage drop occurs.
    tvafter is the second time when it is determined that the system voltage drop has recovered.
    δ vafter is the pseudo-internal phase angle at the time t vafter at which it is determined that the system voltage drop has recovered.
    δ vbefore is the pseudo-internal phase angle at the time t vbefore when the system voltage drop occurs.
    ωvafter is the pseudo-angular velocity at time tvafter when it is determined that the system voltage drop has recovered.
    The renewable energy power plant system according to claim 2, wherein the ω vbefore is the pseudo-angular velocity at the time t vbefore when the system voltage drop occurs.
  4. 　前記周波数ドループブロックは、前記系統電圧低下が発生した場合に、前記系統電圧低下の発生後から前記系統電圧低下が回復するまでの期間は、前記第一時刻の前記疑似内部位相角を保持するように構築された請求項２または３に記載の再生可能エネルギー発電プラントシステム。 When the system voltage drop occurs, the frequency droop block maintains the pseudo internal phase angle at the first time during the period from the occurrence of the system voltage drop to the recovery of the system voltage drop. The renewable energy power plant system according to claim 2 or 3 constructed in the above.
  5. 　前記疑似内部位相角は、予め定めたリセット時間が経過するとリセットされる請求項１～４のいずれか１項に記載の再生可能エネルギー発電プラントシステム。 The renewable energy power plant system according to any one of claims 1 to 4, wherein the pseudo internal phase angle is reset when a predetermined reset time elapses.
  6. 　昇圧用変圧器または送電線を介して同期発電機の近傍の母線と接続される再生可能エネルギー発電プラントシステムに含まれる電力変換装置を制御するように構築され、前記電力変換装置は前記再生可能エネルギー発電プラントシステムが含む再生可能エネルギー発電装置で発電された直流電力を交流電力に変換するものであるプラント制御装置であって、
    　プラント制御装置は、
    　前記電力変換装置の出力側における系統連系点の系統電圧および系統電流に基づいて演算した電力指令値を前記電力変換装置に伝達するように構築された電力指令計算ブロックと、
    　前記電力変換装置の有効電力出力上限値を算出する周波数ドループブロックと、
    　を含み、
    　前記周波数ドループブロックは、前記系統電圧の周波数から求めた角周波数である疑似角速度と、前記疑似角速度の積分値に基づく疑似内部位相角と、を算出し、
    　前記周波数ドループブロックは、前記疑似内部位相角の絶対値が予め定めた基準位相角以上であるときに、前記疑似角速度が増大したら前記有効電力出力上限値を低下させるように構築されたプラント制御装置。     The power converter is constructed to control a power converter included in a renewable energy power plant system connected to a bus in the vicinity of a synchronous generator via a step-up transformer or transmission line, which power converter is said to be the renewable energy. A plant control device that converts DC power generated by a renewable energy power generation device included in a power plant system into AC power.
    The plant controller
    A power command calculation block constructed to transmit a power command value calculated based on the system voltage and system current of the grid interconnection point on the output side of the power converter to the power converter.
    A frequency droop block that calculates the upper limit of the active power output of the power converter, and
    Including
    The frequency droop block calculates a pseudo-angular velocity, which is an angular frequency obtained from the frequency of the system voltage, and a pseudo-internal phase angle based on an integral value of the pseudo-angular velocity.
    The frequency droop block is a plant control device constructed so that when the absolute value of the pseudo internal phase angle is equal to or greater than a predetermined reference phase angle, the active power output upper limit value is lowered when the pseudo angular velocity increases. ..
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WO2013140916A1 (en) * 2012-03-19 2013-09-26 三菱電機株式会社 System stabilization device
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115377992A (en) * 2022-06-27 2022-11-22 国网浙江省电力有限公司丽水供电公司 Power converter fault ride-through control method suitable for wide-range flexible hydrogen production
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