JP2016019373A - Renewable energy power generation facility control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a renewable energy power generation plant control system enabling an electric power system to obtain stable frequency variation suppression effect regardless of power generation state of individual renewable energy power generation equipment.SOLUTION: The renewable energy power generation facility control system is provided which controls renewable energy power generation facilities 41-43, 51 that include a plurality of pieces of renewable energy power generation equipment 411, 421, 431 and 511 for generating power using renewable energy sources, respectively and that are operated so as to be operatively connected with an electric power system. When the absolute value of an output controllable amount of renewable energy power generation equipment 411i becomes lower than the absolute value of an output control target value, the renewable energy power generation facility control system performs control of increasing an output control amount for a renewable energy power generation facility 411i whose output controllable amount has not yet reached its upper limit.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a control system for a renewable energy power generation facility.

  As a countermeasure to the emergence of global environmental problems such as global warming and acid rain, the depletion of fossil resources, and the securing of energy security, power plants using renewable energy sources such as wind power generation and solar power generation Introduction to the power system is progressing. In general, in power systems, as shown in Fig. 1, generator governor-free operation, load frequency control (Load Frequency Control, LFC), economic load distribution control (Economic Load Dispatching Control, EDC) ) Is controlled and operated so as to maintain the frequency within an appropriate range.

  With the increase in the introduction of the above-mentioned renewable energy power plants, there is a concern about a decrease in frequency stability of the power system for the following reasons. First of all, when the number of renewable energy power plants increases, the capacity of the so-called middle load power sources and peak load power sources such as thermal power plants and hydro power plants in the capacity of all power generation facilities will be relatively low, resulting in a lack of adjustment power Is mentioned. In addition, since renewable energy power plants such as wind power generation and solar power generation are often connected to the power system via power converters, they are connected to the power system in conjunction with the decrease in the middle load power source described above. Since the ratio of the rotating machine type power source having inertia is reduced, frequency fluctuation is likely to occur with respect to load fluctuation.

  The decrease in frequency stability is an obstacle to the expansion of the introduction of renewable energy power plants, but it is difficult to take countermeasures only with facilities on the power system side. It will be important to contribute to maintaining the frequency of the system.

  Regarding the contribution of the renewable energy power generation facility to the maintenance of the frequency of the power system, the following patent document 1 describes a frequency of several seconds by adjusting the output of the wind power generation system in accordance with the change in the frequency of the power system and the change in the wind speed. A technique for contributing to suppression of fluctuations is disclosed. Specifically, when the frequency of the power system rises, the generator output is increased by increasing the number of revolutions of the generator and the wind energy is stored as rotational energy. The rotating energy of the machine is lowered and the accumulated rotational energy is released to increase the power generation output.

Special table 2013-501484

  In the technique disclosed in Patent Document 1, the amount that the wind power generation system can adjust the output for frequency control (the amount that can be adjusted) varies depending on the wind speed, so that the control effect for frequency stabilization of the power system becomes unstable. There is a problem.

  An object of the present invention is to provide a control system for a renewable energy power generation facility that can obtain a stable frequency fluctuation suppressing effect in an electric power system regardless of the power generation state of each renewable energy power generation facility.

  In order to solve the above-described problems, a control system for a renewable energy power generation facility according to the present invention has a plurality of renewable energy power generation facilities that generate power using a renewable energy source and operates in conjunction with a power system. A control system for a renewable energy power generation facility that controls a renewable energy power generation facility to be operated, wherein the absolute value of the output controllable amount of the renewable energy power generation facility is less than the absolute value of the output control target amount The control is performed to increase the output of the renewable energy power generation facility that has not reached the upper limit of the output controllable amount.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the control system of the renewable energy power generation facility which can acquire the stable frequency fluctuation suppression effect in an electric power system irrespective of the electric power generation state of each renewable energy power generation facility. .

It is a figure explaining the frequency control method of an electric power system. It is a figure which shows the structural example of the renewable energy power plant which is 1st and 2nd embodiment of this invention. It is a functional block diagram of the control system of the renewable energy power plant which is 1st embodiment of this invention. It is a control flowchart of the control system of the renewable energy power plant which is the first embodiment of the present invention. It is a figure which shows the output characteristic of a wind power generation system. It is a figure which shows the example of control operation | movement of the renewable energy power plant which is 1st embodiment of this invention. It is a functional block diagram of the control system of the renewable energy power plant which is 2nd embodiment of this invention. It is a control flow figure of the control system of the renewable energy power plant which is the second embodiment of the present invention. It is a figure which shows the control operation example of the renewable energy power plant which is 2nd embodiment of this invention. It is a figure which shows the structural example of the renewable energy power plant group which is the 3rd and 4th embodiment of this invention. It is a functional block diagram of the control system of the renewable energy power plant group which is 3rd embodiment of this invention. It is a control flowchart of the control system of the renewable energy power plant group which is 3rd embodiment of this invention. It is a figure which shows the control operation example of the renewable energy power plant group which is 3rd embodiment of this invention. It is a functional block diagram of the control system of the renewable energy power plant group which is the fourth embodiment of the present invention. It is a control flowchart of the control system of the renewable energy power plant group which is the fourth embodiment of the present invention. It is a figure which shows the control operation example of the renewable energy power plant group which is the 4th embodiment of this invention.

  In each example, when the absolute value of the output controllable amount of the renewable energy power generation facility falls below the absolute value of the output control target amount, the output of the renewable energy power generation facility that has not reached the upper limit of the output controllable amount is increased. Control is performed. The target of the renewable energy power generation facility and the renewable energy power generation facility varies depending on which unit is used as a reference. In each embodiment, output adjustment is not performed for each renewable energy power generation facility, but is performed in cooperation with a plurality of renewable energy facilities. Details are as shown in each example.

  For example, when the renewable energy power generation facility is a wind farm and the renewable energy power generation facility is a wind power generation system, the following control is specifically possible. That is, the total output controllable amount of the wind farm for frequency adjustment estimated from the wind speed and the output characteristics of the wind power generation system is the output control amount (output control target) obtained from the control gain and frequency fluctuation specified in advance from the power system. And the control gain of the wind power generation system is increased so as to increase the output control amount of the wind power generation system having a sufficient output controllable amount. As a result, it is possible to secure an output control amount necessary for frequency fluctuation suppression as a wind farm. DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings. In addition, the following is only an Example, and is not intended to limit the embodiment of the present invention.

  FIG. 2 is an example of a schematic configuration of a renewable energy power plant (hereinafter referred to as a RES power plant) according to the first embodiment of the present invention. In this embodiment, the RES power plant corresponds to a renewable energy power generation facility, and the single wind power generation system corresponds to a renewable energy power generation facility.

  The power generation output fluctuates depending on the weather conditions in the power system 1 in which large-scale power stations G1 and G2 and substations 21 to 26 of a power system equivalent to a thermal power plant or a hydropower plant are connected by a transmission line 3. A RES power plant composed of wind power plants 41 to 43 and a solar power plant 51 is connected. The power generation output of each RES power plant is supplied via a transmission line 3 to a consumer (not shown) connected to the power system. These RES power plants do not need to be concentrated in a specific area, but are distributed in places with good wind conditions or solar radiation. In addition, as a RES power plant, only the wind power plants 41 to 43 and the solar power plant 51 are shown in FIG. 2 for simplicity, but it is assumed that a larger number of RES power plants are actually connected. . In addition, as elements constituting the RES power plant and the power system, the minimum elements necessary for the explanation of the present invention are described.

  The wind power plants 41 to 43 are a wind power generation system group 411, 421, 431 composed of a plurality of windmills, generators, interconnection power converters, and the like, and an interconnection for connecting the wind power generation system group to an electric power system. Transformers 412, 422, 432, total power output of the wind power generation system group, voltage detectors 413, 423 for measuring the voltage and current of connection points (hereinafter referred to as grid connection points) with the power system, 433 and current detectors 414, 424, 434, functions to calculate and transmit control commands for adjusting the output of wind power plants based on measured voltage / current and weather characteristics (wind speed / wind direction, temperature, etc.) And a control system 40 having Similarly, the solar power plant 51 includes a solar power generation system 51 including a plurality of solar panels 511, an interconnection power converter 515, and the like, a power generation output of the solar power generation system, a voltage at a grid connection point, and the like. The control system 50 has a function of calculating and transmitting a control command for adjusting the output of the solar power plant based on electrical characteristics and weather characteristics (such as solar radiation and temperature).

FIG. 3 shows a functional configuration diagram of the control system 40 of the wind power plant among the RES power plants. The functional configuration of the control system 50 of the solar power plant 51 is the same. Here, the wind power plant 41 will be described as an example. A control arithmetic unit 401 that calculates a control command to be transmitted to the wind power generation system group 411 of the wind power plant 41, a data storage device 405 that stores measurement information of the wind power plant, a history of control commands, and the like, and an operator issues an operation command. An input device 402 for inputting, a display device 403 for an operator to confirm an operation state, and a communication device 404 for controlling transmission / reception of control commands and measurement information. The communication device 404 performs information communication with the wind power generation system group 411 via a communication line. The control arithmetic unit 401 includes a measurement data detection unit 4011, a frequency variation calculation unit 4012 for calculating a frequency variation Δf _G in the GF region from the frequency f of the power system 1, and a control preset with the calculated frequency variation Δf _G Based on the constant, the output control amount of each wind power generation system group 411i (corresponding to the output control target amount of each wind power generation system) ΔP _{G_WTi} and the output control amount of the wind power plant 41 (corresponding to the output control target amount of the wind power plant) ) GF output control amount calculation unit 4013 and 4014 for calculating ΔP _{G_WF} , wind turbine characteristic data detection unit 4015 such as rotor speed and blade pitch angle of wind power generation system, measured wind speed and output characteristics of each wind power system group 411i output controllable amount [Delta] P _{G_WTi} for frequency adjustment of the output controllable amount estimating unit 4016, GF region for calculating an output controllable amount ΔP _{G_WTi} ^* for frequency adjustment of the GF area of each wind turbine unit 411i based on ^* Using the output controllable amount ΔP _{G_WF} ^* output controllable amount calculation unit 4017 for calculating the wind farm 41, the wind power generation system group 411i output control amount [Delta] P _{G_WTi} output controllable amount ΔP _{G_WTi} ^*, and the wind power plant 41 is compared with the output control amount ΔP _{G_WF} and the output controllable amount ΔP _{G_WF} ^* to determine whether or not to change the control constant of each wind power generation system group 411i. And a control command calculation unit 4019 for calculating a change value.

  Next, a processing flow of the control system 40 of the wind power plant 41 will be described with reference to FIG. First, in the process S1, the electric power system frequency, the electrical characteristics data such as the voltage and current at the connection point, and the weather characteristic data such as the wind speed, which are periodically measured and transmitted by the wind power plant 41, are read from the data storage device 405. . In the case of a solar power plant, solar radiation and temperature are read instead of wind speed.

In the process S2, using the measured frequency f of the power system 1, a frequency fluctuation Δf _G that is a target of frequency stabilization by adjusting the output of the wind power plant 41 is calculated. Here, the time domain in which the frequency fluctuation is detected is about several seconds to several tens of seconds assuming the GF region of FIG. Specifically, the fluctuation component of the frequency f of the power system 1 is detected by a band pass filter. The time constants τ1 and τ2 (τ1> τ2) when the bandpass filter is composed of a first-order low-pass filter and a high-pass filter are given by Equation (1).


Here, fc1 and fc2 are the cut-off frequency [Hz] of the low-pass filter and the high-pass filter, respectively, and T1 and T2 are their time periods [s].

In the process S3, an output control amount ΔP _{G_WF,} and outputs the control amount [Delta] P _{G_WTi} of the wind power generation system group 411i of the wind power plant 41 is determined based on the frequency variation information of the control constants and the power system which is previously set to a wind power plant It is done. Specifically, each can be calculated by the following formula.

ΔP _{G_WF} = −K _G・ Δf _G (2)

ΔP _{G_WTi} = −K _Gi・ Δf _G (3)

Here, K _G control gain preset in the wind farm 41, K _Gi is a control gain to be set to each wind turbine system group 411I, for example, as an initial value using the number n of the wind power generation system group 411I It is defined by the following formula.

K _Gi = K _G / n (4)

In the process S4, first, the output controllable amount ΔP _{G_WTi} ^* of each wind power generation system group 411i is _determined by, for example, the intensity of a renewable energy source (for example, wind speed corresponds to wind power generation, solar radiation or temperature for solar power generation). And the following formula defined based on the output characteristics of the wind power generation system. In addition, as for the intensity | strength of a renewable energy source, not only a measured value can be used but a predicted value etc. can be used.

ΔP _{G_WTi} ^* = F (Si, θ, ωi) (5)

Here, Si is the wind speed measured by the wind power generation system 411i, θ is the pitch angle of the blade at that time, and ωi is the rotational speed of the rotor at that time. Formula (5) is a function defined based on output power-rotor rotational speed characteristic data of a wind power generation system defined for each wind speed at a pitch angle of a certain blade shown in FIG. Then calculated by the following equation output controllable amount ΔP _{G_WF} ^* of the wind power plant 41 as the sum of the output controllable amount ΔP _{G_WTi} ^* of the wind power generation system 411I. The control system may have a function of notifying at least one of the output controllable amount of the renewable energy power generation facility and the output controllable amount of the renewable energy power generation facility to the control system of the power system. In this case, on the power system side, it is possible to grasp whether or not the renewable energy power generation facility or individual equipment plays a role as expected against frequency fluctuations.


In the case of a photovoltaic power plant, the output controllable amount ΔP _{G_PCSi} ^* of the _grid power converter 515i is calculated using, for example, the solar radiation measurement value Sr (W / m ² ) and the outside air temperature To (° C.). The output controllable amount ΔP _{G_PV} ^* of the photovoltaic power plant 51 is calculated as the sum of these, as in the equation (6).

ΔP _{G_PCSi} ^* = Sr ・ Ks ・ Kpv ・ Kt (To) ・ Kb ・ Kc ・ Kpcs × 10 ^-3 −P_ _PCSi (7)
However,
Ks: Solar radiation correction factor Kpv: Panel capacity conversion factor
Kt (To): Temperature correction coefficient Kb: Dirt coefficient
Kc: Cable efficiency factor Kpcs: PCS conversion efficiency factor
_{P_PCSi} : Current power output

In process S5, the wind power generation system 411i of the output control amount [Delta] P _{G_WTi} output controllable amount ΔP _{G_WTi} ^*, and compared to the output control quantity [Delta] P _{G_WF} wind farm 41 outputs controllable amount ΔP _{G_WF} ^*, the wind power generation system It is determined whether to change the control constant of the group 411i. Specifically, when the following equation is satisfied, i.e. only when the wind farm 41 can not supply a predetermined output control amount to the power system 1, to change the control gain K _G i of the wind power generation system 411I.

｜ ΔP _{G_WF} ｜ ＞ ｜ ΔP _{G_WF} ^* ｜ (8)

In the process S6, when Formula (8) is established, that is, when the absolute value of the output control amount ΔP _{G_WF} of the wind power plant 41 is larger than the absolute value of the output controllable amount ΔP _{G_WF} ^* of the wind power plant 41, the formula ( wind turbine system 411i of 9) is satisfied, namely the absolute value absolute value is larger output controllable amount ΔP _{G_WTi} ^* than the output control amount [Delta] P _{G_WTi,} wind power generation system 411i control that does not reach the upper limit of the output controllable amount The gain K _G i is changed by Expression (10).

| ΔP _{G_WTi} | <| ΔP _{G_WTi} ^* | (9)
K _G i '= α ・ K _G i (10)

Here, α is a constant larger than 1. Since α is larger than 1, the wind power generation system 411i that has not reached the upper limit of the output controllable amount increases the output.

Finally, in process S7, the control gain K _Gi is transmitted to the wind power generation system 411i.

  FIG. 6 shows a control operation example of the RES power plant according to the first embodiment of the present invention. Here, as in FIG. 3, the wind power generation system 41 will be described as an example.

This figure shows an example in which the frequency fluctuation Δf _G repeats increasing and decreasing. When Formula (8) is not satisfied, that is, when the wind power plant 41 can supply the predetermined output control amount ΔP _{G_WF} determined by Formula (2) to the power system 1, it is based on the control flow shown in FIG. The control gain K _G i of the wind power generation system 411i is not changed. Next, as shown in (a) of the figure, the absolute value of the output control amount ΔP _{G_WF} required by the wind power plant 41 is the absolute value of the output controllable amount ΔP _{G_WF} * given by Equation (5) and Equation (6). The case where it becomes larger than the value will be described. In this case, as shown in FIG. 4B, at least one of the wind power generation systems 411i is in a state where the output controllable amount ΔP _{G_WTi} * is insufficient and the necessary output control amount determined by Equation (3) cannot be supplied. It has become. Therefore, in the present invention, as shown in (c) of the figure, among the wind power generation systems 411i that satisfy Equation (9), that is, those that have a margin in the output controllable amount ΔP _{G_WTi} *, Equation (10) Based on this, the control gain K _G i is changed to K _G i ′ and the absolute value of the output control amount ΔP _{G_WTi} is increased, so that the predetermined output control amount ΔP _{G_WF} determined by the equation (2) in FIG. Can do.

  As described above, according to the present invention, the predetermined output control amount can be stably supplied from the wind power plant regardless of the output state of the wind power generation system depending on the wind condition with respect to the frequency fluctuation in the governor-free region of the power system. Therefore, it is possible to contribute to suppression of frequency fluctuation.

  Next, the second embodiment of the present invention will be described with reference to the configuration diagram of the RES power plant shown in FIG. In the first embodiment, frequency fluctuation, which is a governor-free control region with a period of several seconds to several tens of seconds, is targeted. However, in this embodiment, frequency fluctuation, which is a control region of an LFC with a period of several minutes to several tens of seconds, is targeted. ing. In this embodiment, as in the first embodiment, the RES power plant corresponds to a renewable energy power generation facility, and the single wind power generation system corresponds to a renewable energy power generation facility.

  When adjusting the output by using the inertia energy of wind turbine blades and generators of a wind power generation system, it can contribute to the suppression of frequency fluctuations of a few seconds, but the available inertia energy is small so There is a problem in that it cannot cope with output adjustment for contributing to suppression of frequency fluctuations of several minutes or more. On the other hand, in the present embodiment, it is possible to contribute to the suppression of frequency fluctuations over a period of several minutes in the LFC region.

FIG. 7 shows a functional configuration diagram of the control system 40 of the wind power plant in the second embodiment. The functional configuration of the control system 50 of the solar power plant 51 is the same. Here, the wind power plant 41 will be described as an example. A control arithmetic unit 406 that calculates a control command to be transmitted to the wind power generation system group 411 of the wind power plant 41, a data storage device 405 that stores measurement information of the wind power plant, a history of control commands, and the like, and an operator issues an operation command. An input device 402 for inputting, a display device 403 for an operator to confirm an operation state, and a communication device 404 for controlling transmission / reception of control commands and measurement information. The communication device 404 performs information communication with the wind power generation system group 411 via a communication line. The control calculation device 406 includes a measurement data detection unit 4061, a frequency variation calculation unit 4062 for calculating the frequency variation Δf _L in the LFC region from the frequency f of the power system 1 (this is, for example, the frequency of the power system 1 in the first embodiment) It may be used together with the frequency fluctuation calculation unit 4012 for calculating the frequency fluctuation Δf _G of the governor-free region from f. For example, the same applies to the fourth embodiment, etc.), and the calculated frequency fluctuation Δf _L is preset. Based on the control constant, the output control amount of each wind power generation system group 411i (corresponding to the output control target amount of each wind power generation system) ΔP _{G_WTi} and the output control amount of the wind power plant 41 (the output control target amount of the wind power plant) out for frequency adjustment of the LFC area of each wind turbine unit 411i based on the output characteristics of the relevant) ΔP _{L_WF} LFC output control amount calculation unit 4063 and 4064 is calculated and a measured wind speed the wind power generation system group 411i Calculates an output controllable amount ΔP _{L_WF} ^* of the wind power plant 41 with a controllable amount ΔP _{L_WTi} ^* possible output control calculates the amount estimation unit 4066, outputs controllable amount for frequency adjustment of the LFC region ΔP _{L_WTi} ^* output controllable amount calculation unit 4067, compares each wind power generation system group output control amount [Delta] P _{L_WTi} output controllable amount of 411i ΔP _{L_WTi} ^*, and an output control amount [Delta] P _{L_WF} wind farm 41 outputs controllable amount ΔP _{L_WF} ^* The control constant change necessity determination unit 4068 that determines whether or not to change the control constant of each wind power generation system group 411i, and the control command calculation unit 4069 that calculates the change value of the control constant.

  Next, a processing flow of the control system 40 of the wind power plant 41 will be described with reference to FIG.

  First, in the process S1, the electric power system frequency, the electrical characteristics data such as the voltage and current at the connection point, and the weather characteristic data such as the wind speed, which are periodically measured and transmitted by the wind power plant 41, are read from the data storage device 405. . In the case of a solar power plant, solar radiation and temperature are read instead of wind speed.

In the process S2, using the measured frequency f of the power system 1, a frequency fluctuation Δf _L that is a target of frequency stabilization by adjusting the output of the wind power plant 41 is calculated. Here, the time domain in which the frequency fluctuation is detected is set to about several tens of seconds to 20 minutes assuming the LFC area in FIG. Specifically, the fluctuation component of the frequency f of the power system 1 is detected by a band pass filter. The time constants τ1 and τ2 (τ1> τ2) when the bandpass filter is composed of a first-order low-pass filter and a high-pass filter are given by Equation (1).

In the process S3, an output control amount ΔP _{L_WF,} and outputs the control amount [Delta] P _{L_WTi} of the wind power generation system group 411i of the wind power plant 41 is determined based on the frequency variation information of the control constants and the power system which is previously set to a wind power plant It is done. Specifically, each can be calculated by the following formula.

ΔP _{G_WF} = −K _L・ Δf _G (11)

ΔP _{G_WTi} = −K _Li・ Δf _G (12)

Here, K _L is a control gain set in advance in the wind power plant 41, and K _Li is a control gain set in each wind power generation system group 411i. For example, the number n of each wind power generation system group 411i is used as an initial value. It is defined by the following formula.

K _Li = K _L / n (13)

In the process S4, first, the output controllable amount _{ΔPL_WTi} ^* of each wind power generation system group 411i is calculated by the following equation using, for example, the measured value of the wind speed and the measured value of the current output _{P_WTi} of each wind power generation system.

ΔP _{L_WTi} ^* = (1/2) ・ ρ ・ Ai ・ V ³・ ηi × m × 10 ⁶ − P_ _WTi (14)
here,
ρ: Air density (kg / m ³ )
Ai: Wind receiving area (m ² ) of the wind turbine blade of the wind power generation system 411i,
Vi: Wind speed (m / s) measured by wind power generation system 411i
ηi: Power generation efficiency of wind power generation system 411i (%)
It is.

Then calculated by the following equation output controllable amount ΔP _{L_WF} ^* of the wind power plant 41 as the sum of the output controllable amount ΔP _{L_WTi} ^* of the wind power generation system 411I.


In the case of a photovoltaic power plant, the output controllable amount ΔP _{L_PCSi} ^* of the _grid power converter 515i is calculated using the solar radiation measurement value Sr (W / m ² ) and the outside air temperature To (° C). Similar to Equation (157), the output controllable amount ΔP _{L_PV} ^* of the photovoltaic power plant 51 is calculated as the sum of these.

ΔP _{L_PCSi} ^* = Sr ・ Ks ・ Kpv ・ Kt (To) ・ Kb ・ Kc ・ Kpcs × 10 ^-3 −P_ _PCSi (16)
However,
Ks: Solar radiation correction factor Kpv: Panel capacity conversion factor
Kt (To): Temperature correction coefficient Kb: Dirt coefficient
Kc: Cable efficiency factor Kpcs: PCS conversion efficiency factor

In process S5, the wind power generation system 411i of the output control amount [Delta] P _{L_WTi} output controllable amount ΔP _{L_WTi} ^*, and compared to the output control quantity [Delta] P _{L_WF} wind farm 41 outputs controllable amount ΔP _{L_WF} ^*, the wind power generation system It is determined whether to change the control constant of the group 411i. Specifically, when the following equation is satisfied, i.e. only when the wind farm 41 can not supply a predetermined output control amount to the power system 1, to change the control gain K _L i of the wind power generation system 411I.

| ΔP _{L_WF} | >> | ΔP _{L_WF} ^* | (17)

In the process S6, when Formula (17) is satisfied, that is, when the absolute value of the output control amount ΔP _{L_WF} of the wind power plant 41 is larger than the absolute value of the output controllable amount ΔP _{L_WF} ^* of the wind power plant 41, the formula ( wind turbine system 411i of 18) is satisfied, namely the absolute value absolute value is larger output controllable amount ΔP _{L_WTi} ^* than the output control amount [Delta] P _{L_WTi,} wind power generation system 411i control that does not reach the upper limit of the output controllable amount the gain K _L i to change the equation (19).

| ΔP _{L_WTi} | <| ΔP _{L_WTi} ^* | (18)

K _L i '= β ・ K _L i (19)

Here, β is a constant larger than 1. Since β is larger than 1, the wind power generation system 411i that has not reached the upper limit of the output controllable amount increases the output.

Finally, in the process S7, the transmit control gain K _L i to a wind power generation system 411I.

  FIG. 9 shows a control operation example of the renewable energy power plant that is the second embodiment of the present invention. Here, similarly, the wind power generation system 41 will be described as an example.

The figure shows an example in which the frequency fluctuation Δf _L is repeatedly increased and decreased. When Formula (17) is not satisfied, that is, when the wind power plant 41 can supply the predetermined output control amount ΔP _{L_WF} determined by Formula (11) to the power system 1, it is based on the control flow shown in FIG. control gain K _L i of the wind power generation system 411i is not changed. Next, as shown in (a) of the figure, the absolute value of the output control amount ΔP _{L_WF} required at the wind power plant 41 is the absolute value of the output controllable amount ΔP _{L_WF} * given by Equation (14) and Equation (15). The case where it becomes larger than the value will be described. In this case, as shown in FIG. 4B, at least one of the wind power generation systems 411i is in a state where the output controllable amount ΔP _{L_WTi} * is insufficient and the necessary output control amount determined by Expression (12) cannot be supplied. ing. Therefore, in the present invention, as shown in FIG. 8C, for the wind power generation system 411i that satisfies the formula (17), that is, the output controllable amount ΔP _{L_WTi} * that has a margin, the formula (18) Based on this, the control gain K _L i ′ is changed to increase the absolute value of the output control amount, so that the predetermined output control amount _{ΔPG_WF} determined by the equation (11) in FIG.

  As described above, according to the present invention, a predetermined output control amount can be stably supplied from the wind power plant regardless of the output state of the wind power generation system depending on the wind conditions, even for frequency fluctuations in the LFC region of the power system. Therefore, it is possible to contribute to suppression of frequency fluctuation.

  Next, a control system for a plurality of RES power plant groups according to the third embodiment of the present invention will be described in detail with reference to the drawings. In Example 1 and Example 2, the RES power plant corresponds to a renewable energy power generation facility, and the single wind power generation system corresponds to a renewable energy power generation facility. On the other hand, in this embodiment, the RES power plant corresponds to a renewable energy power generation facility, and the RES power plant group corresponds to a renewable energy power generation facility.

  FIG. 10 is an example of a schematic configuration of a plurality of RES power plant groups according to the third embodiment. The power generation output fluctuates according to the weather conditions in the power system 1 in which the large-scale power stations G1 and G2 and the substations 21 to 25 of the power system corresponding to the thermal power station or the hydroelectric power generation are connected by the transmission line 3. A RES power plant composed of wind power plants 41 to 43 and a solar power plant 51 is connected. The power generation output of each RES power plant is supplied via a transmission line 3 to a consumer (not shown) connected to the power system. These RES power plants do not need to be concentrated in a specific area, but are distributed in places with good wind conditions or solar radiation. In addition, as a RES power plant, only the wind power plants 41 to 43 and the solar power plant 51 are shown in FIG. 2 for simplicity, but it is assumed that a larger number of RES power plants are actually connected. . In addition, as elements constituting the RES power plant and the power system, the minimum elements necessary for the explanation of the present invention are described.

  The wind power plants 41 to 43 are a wind power generation system group 411, 421, 431 composed of a plurality of windmills, generators, interconnection power converters, and the like, and an interconnection for connecting the wind power generation system group to an electric power system. Transformers 412, 422, 432, total power output of the wind power generation system group, voltage detectors 413, 423 for measuring the voltage and current of connection points (hereinafter referred to as grid connection points) with the power system, 433 and current detectors 414, 424, 434, functions to calculate and transmit control commands for adjusting the output of wind power plants based on measured voltage / current and weather characteristics (wind speed / wind direction, temperature, etc.) And a control system 40 having Similarly, the solar power plant 51 includes a solar power generation system 51 including a plurality of solar panels 511, an interconnection power converter 515, and the like, a power generation output of the solar power generation system, a voltage at a grid connection point, and the like. The control system 50 has a function of calculating and transmitting a control command for adjusting the output of the solar power plant based on electrical characteristics and weather characteristics (such as solar radiation and temperature).

  The wind power plants 41 to 43 and the solar power plant 51 constituting the RES power plant group are connected to the control system 6 of the RES power plant group via the communication line 7, and between each power plant and the control system 6, Information is input / output via the communication line 7.

  FIG. 11 shows a functional configuration diagram of the control system 6 of the RES power plant group. A control arithmetic unit 61 for calculating control commands to be transmitted to the control systems 40 and 50 of the RES power plant group, a data storage device 65 for storing the measurement information of the RES power plant group, a history of control commands, and the like. An input device 62 for inputting, a display device 63 for an operator to confirm an operation status, and a communication device 64 for controlling transmission / reception of control commands and measurement information. The communication device 64 performs information communication with the RES power plant group via the communication line 7.

The control calculation device 61 includes a measurement data detection unit 611, a frequency variation calculation unit 612 for calculating a frequency variation Δf _G in the GF region from the frequency f of the power system 1, and a control set in advance with the calculated frequency variation Δf _G Based on the constant, the output control amount of each RES power plant 41 to 43 and 51 (corresponding to the output control target amount of each RES power plant) ΔP _{G_RESi} , and its combined output control amount (the combined output control target amount of RES power plant) Applicable) GF output control amount calculation unit 613 and 614 for calculating ΔP _{G_RES} , GF of each RES power plant 41 to 43 and 51 based on measured wind speed or solar radiation and output state of each RES power plant 41 to 43 and 51 The output controllable amount estimation unit 616 for calculating the output controllable amount ΔP _{G_RESi} ^* for adjusting the frequency of the region, and the output controllable amount ΔP _{G_RES} ^* that is a composition of the RES power plant group using the output controllable amount ΔP _{G_RESi} ^* Output controllable amount calculating section 617, each RES power plant 41 to 43 and 51 Output control amount [Delta] P _{G_RESi} output controllable amount ΔP _{G_RESi} ^*, and RES output control amount [Delta] P _{G_RES} of plant groups and compares the output controllable amount ΔP _{G_RES} ^*, control constants of the RES power plants 41 to 43 and 51 A control constant change necessity determination unit 618 for determining whether to change the control constant, and a control command calculation unit 619 for calculating a change value of the control constant.

  Next, a processing flow of the control system 6 of the RES power plants 41 to 43 and 51 will be described with reference to FIG.

  First, in process S1, the electrical characteristics data such as the frequency of the power system, the voltage and current at the connection point, and the weather characteristics data such as wind speed, which are periodically measured and transmitted by the RES power plants 41 to 43 and 51, are stored. Read from device 65. In the case of a solar power plant, solar radiation and temperature are read instead of wind speed.

In the process S2, using the measured frequency f of the power system 1, a frequency fluctuation Δf _G to be frequency stabilized by adjusting the output of the RES power plants 41 to 43 and 51 is calculated. Here, the time domain in which the frequency fluctuation is detected is about several seconds to several tens of seconds assuming the GF region of FIG. Specifically, the fluctuation component of the frequency f of the power system 1 is detected by a band pass filter. The time constants τ1 and τ2 (τ1> τ2) when the bandpass filter is composed of a first-order low-pass filter and a high-pass filter are given by Equation (1).

In process S3, RES plant groups combined output control amount ΔP _{G_RES,} and outputs the control amount [Delta] P _{G_RESi} of the RES power plants 41 to 43 and 51 the frequency fluctuation of the control constants and the power system which is previously set to the RES plant group Determined based on information. Specifically, each can be calculated by the following formula.

ΔP _{G_RES} = −K _G・ Δf _G (20)

ΔP _{G_RESi} = −K _Gi・ Δf _G (21)

Here, K _G is preset control gain to the combined output of the RES plant group, K _Gi is a control gain to be set to each RES plants 41-43 and 51, for example the RES power station as an initial value It is defined by the following equation using a number m.

K _Gi = K _G / m (22)

In the process S4, the controllable amount ΔP _{G_RESi} ^* calculated and transmitted using, for example, Equation (5) or Equation (6) in the control system of each RES power plant, and the sum of these is used as a composite of the RES power plants. The output controllable amount ΔP _{G_RES} ^* is calculated by the following equation.

In the process S5, the output control amount ΔP _{G_RESi} and the output controllable amount ΔP _{G_RESi} ^{* of} each RES power plant 41 to 43 and 51, and the combined output control amount ΔP _{G_RES} and the combined output controllable amount ΔP _{G_RES} ^* of the RES power plant group are _obtained ^. A comparison is made to determine whether or not to change the control constant of each RES power plant 41 to 43 and 51. Specifically, the control of each RES power plant 41 to 43 and 51 is performed only when the following equation holds, that is, when the combined output of the RES power plant group cannot supply a predetermined output control amount to the power system 1. Change the gain K _G i.

| ΔP _{G_RES} | >> | ΔP _{G_RES} ^* | (24)

In process S6, when Formula (24) is satisfied, that is, when the absolute value of the combined output control amount ΔP _{G_RES} of the RES power station group is larger than the absolute value of the combined output controllable amount ΔP _{G_RES} ^* of the RES power station group, equation (25) RES power plants 41 to 43 and 51 is established, i.e., the absolute value is larger output controllable amount ΔP _{G_RESi} ^* than the absolute value of the output control amount [Delta] P _{G_RESi,} it does not reach the upper limit of the output controllable amount The control gain K _G i of the RES power plant is changed using Equation (26).

_{| ΔP G_ RES i | <|} ΔP G_ RES i * | (25)

K _G i '= γ ・ K _G i (26)

Here, γ is a constant larger than 1. Since γ is larger than 1, the RES power plant that has not reached the upper limit of the output controllable amount increases the output.

Finally, in process S7, the control gain K _Gi is transmitted to the control system of the RES power plants 41 to 43 and 51.

  FIG. 13 shows a control operation example of the renewable energy power plant group according to the third embodiment of the present invention.

This figure shows an example in which the frequency fluctuation Δf _G repeats increasing and decreasing. If Equation (24) does not hold, that is, if the combined output of the RES power plant group can supply the predetermined output control amount _{ΔPG_RES} determined by Equation (20) to the power system 1, the control shown in FIG. Based on the flow, the control gain K _{Gi of the} RES power plants 41 to 43 and 51 is not changed. Next, as shown in (a) of the figure, the absolute value of the output control amount ΔP _{G_RES} required in the RES power station group is larger than the absolute value of the output controllable amount ΔP _{G_RES} * given by Equation (23). The case will be described. In this case, as shown in FIG. 5B, at least one of the RES power plants 41 to 43 and 51 _{lacks the} output controllable amount ΔP _{G_RESi} * and supplies the necessary output control amount determined by Equation (21). It is in a state where it cannot be done. Therefore, in the present invention, as shown in FIG. 5C, among the RES power plants 41 to 43 and 51 that satisfy the formula (25), that is, the output controllable amount ΔP _{G_RESi} * has a margin, the formula Based on (26), the control gain K _G i is changed to K _G i ′ and the absolute value of the output control amount is increased, so the predetermined output control amount ΔP _{G_RES} determined by the equation (20) in FIG. can do.

  As described above, according to the present invention, the predetermined output control can be performed as the combined output of the RES power plant group regardless of the output state of the RES power plant depending on the wind condition and the solar radiation with respect to the frequency fluctuation in the governor-free region of the power system. Since the amount can be supplied stably, it is possible to contribute to suppression of frequency fluctuation.

  Next, a fourth embodiment of the present invention will be described using the configuration diagram of the RES power plant group shown in FIG. In the third embodiment, frequency fluctuation, which is a governor-free control region with a period of several seconds to several tens of seconds, is targeted. However, in this embodiment, frequency fluctuation, which is a control region of an LFC with a period of several minutes to several tens of minutes, is targeted. ing. Also in this embodiment, the RES power plant corresponds to a renewable energy power generation facility, and the RES power plant group corresponds to a renewable energy power generation facility.

  When adjusting the output by using the inertia energy of wind turbine blades and generators of a wind power generation system, it can contribute to the suppression of frequency fluctuations of a few seconds, but the available inertia energy is small so There is a problem in that it cannot cope with output adjustment for contributing to suppression of frequency fluctuations of several minutes or more. On the other hand, in the present embodiment, it is possible to contribute to the suppression of frequency fluctuations over a period of several minutes in the LFC region.

  FIG. 14 shows a functional configuration diagram of the control system 6 of the RES power plant group in the fourth embodiment. A control arithmetic unit 61 for calculating control commands to be transmitted to the control systems 40 and 50 of the RES power plant group, a data storage device 65 for storing the measurement information of the RES power plant group, a history of control commands, and the like. An input device 62 for inputting, a display device 63 for an operator to confirm an operation status, and a communication device 64 for controlling transmission / reception of control commands and measurement information. The communication device 64 performs information communication with the RES power plant group via the communication line 7.

The control arithmetic unit 66 includes a measurement data detection unit 661, a frequency fluctuation calculation unit 662 for calculating the frequency fluctuation Δf _{L in the} LFC region from the frequency f of the power system 1, the calculated frequency fluctuation Δf _L and a preset control constant Based on the output control amount of each RES power plant 41 to 43 and 51 (corresponding to the output control target amount of each RES power plant) _{ΔPL_RESi} and its combined output control amount (corresponding to the composite output control target amount of RES power plant) ) LFC output control amount calculation unit 663 and 664 for calculating ΔP _{L_RES} , LFC region of each RES power plant 41 to 43 and 51 based on the measured wind speed or solar radiation and the output state of each RES power plant 41 to 43 and 51 output controllable amount estimating unit 666 calculates an output controllable amount ΔP _{L_RESi} ^* for frequency adjustment, the output controllable amount ΔP _{L_RESi} ^* can output control is the synthesis of RES plant group with a quantity ΔP _{L_RES} ^* Output controllable amount calculation unit 667 to be calculated, each RES power plant 41 to 43 and 51 Output control amount [Delta] P _{L_RESi} output controllable amount ΔP _{L_RESi} ^*, and RES output control amount [Delta] P _{L_RES} of plant groups and compares the output controllable amount ΔP _{L_RES} ^*, control constants of the RES power plants 41 to 43 and 51 A control constant change necessity determination unit 668 for determining whether to change the control constant, and a control command calculation unit 669 for calculating a change value of the control constant.

  Next, the processing flow of the control system 6 for the RES power plant group will be described with reference to FIG.

  First, in process S1, the electrical characteristics data such as the frequency of the power system, the voltage and current at the connection point, and the weather characteristics data such as wind speed, which are periodically measured and transmitted by the RES power plants 41 to 43 and 51, are stored. Read from device 65. In the case of a solar power plant, solar radiation and temperature are read instead of wind speed.

In the process S2, using the measured frequency f of the power system 1, a frequency fluctuation Δf _L that is a target of frequency stabilization by adjusting the output of the RES power plant group is calculated. Here, the time domain in which the frequency fluctuation is detected is set to about several tens of seconds to 20 minutes assuming the LFC area in FIG. Specifically, the fluctuation component of the frequency f of the power system 1 is detected by a band pass filter. The time constants τ1 and τ2 (τ1> τ2) when the bandpass filter is composed of a first-order low-pass filter and a high-pass filter are given by Equation (1).

In process S3, RES plant groups combined output control amount ΔP _{L_RES,} and outputs the control amount [Delta] P _{L_RESi} of the RES power plants 41 to 43 and 51 the frequency fluctuation of the control constants and the power system which is previously set to the RES plant group Determined based on information. Specifically, each can be calculated by the following formula.

ΔP _{L_RES} = −K _L・ Δf _L (27)

ΔP _{L_RESi} = −K _Li・ Δf _L (28)

Here, K _L is preset control gain to the combined output of the RES plant group, K _Li are control gain set to each RES plants 41-43 and 51, for example the RES power station as an initial value Using the number m of 41 to 43 and 51, it is defined by the following formula.

K _Li = K _L / m (29)

In process S4, the output controllable amount ΔP _{G_RESi} ^* calculated and transmitted using Equation (5) and Equation (6) in the control system of each RES power plant is used, and the resultant output is the combined output of the RES power plant group. The controllable amount ΔP _{G_RES} ^* is calculated by the following equation.

Then calculated by the following equation RES plants group combined output controllable amount ΔP _{L_RES} ^* as the sum of the output controllable amount ΔP _{L_RESi} ^* of RES power plants 41 to 43 and 51.

In the process S5, the output control amount ΔP _{L_RESi of} each RES power plant 41 to 43 and 51 and its output controllable amount ΔP _{L_RESi} ^* , and the output control amount ΔP _{L_RES} of the RES power plant group and its output controllable amount ΔP _{L_RES} ^* A comparison is made to determine whether or not to change the control constant of each RES power plant 41 to 43 and 51. Specifically, the control of each RES power plant 41 to 43 and 51 is performed only when the following equation holds, that is, when the combined output of the RES power plant group cannot supply a predetermined output control amount to the power system 1. Change the gain K _L i.

| ΔP _{L_RES} |> | ΔP _{L_RES} ^* | (31)

In process S6, when the equation (31) is satisfied, it changes the control gain K _L i of RES power plants 41 to 43 and 51 equation (32) is satisfied by Equation (33).

| ΔP _{L_RESi} | <| ΔP _{L_RESi} ^* | (32)

K _L i '= δ ・ K _L i (33)

Here, δ is a constant larger than 1.

Finally, in the process S7, the transmit control gain K _L i to each RES plants 41-43 and 51.

  FIG. 16 shows an example of the control operation of the RES power plant group according to the fourth embodiment of the present invention.

The figure shows an example in which the frequency fluctuation Δf _L is repeatedly increased and decreased. When Equation (31) does not hold, that is, when the combined output of the RES power plant group can supply the predetermined output control amount _{ΔPL_RES} determined by Equation (27) to the power system 1, the control shown in FIG. control gain K _L i of each RES power plants 41 to 43 and 51 based on the flow is not changed. Next, as shown in FIG. 16 (a), the absolute value of the composite output control amount ΔP _{L_RES} required in the RES power plant group is larger than the absolute value of the output controllable amount ΔP _{L_RES} * given by Equation (30). A case will be described. In this case, as shown in FIG. 5B, at least one of the RES power plants 41 to 43 and 51 _{lacks the} output controllable amount _{ΔPL_RESi} *, and the required output control amount determined by the equation (28). Cannot be supplied. Therefore, in the present invention, as shown in FIG. 4C, among the RES power plants 41 to 43 and 51 that satisfy the equation (32), that is, the output controllable amount ΔP _{L_RESi} * has a margin, Since the control gain K _L i ′ is changed based on (33) and the absolute value of the output control amount is increased, the predetermined output control amount ΔP _{L_RES} determined by the equation (27) in FIG. .

  As described above, according to the present invention, a predetermined output control amount can be set as a combined output of the RES power plant group regardless of the output state of the RES power plant depending on wind conditions and solar radiation with respect to the frequency fluctuation in the LFC region of the power system. Since it can supply stably, it becomes possible to contribute to suppression of a frequency fluctuation.

1 ... Power system, G1, G2 ... Large-scale power plant, 2 ... Substation, 3 ... Transmission line, 40 ... Control system for wind power plant, 41, 42, 43 ...・ Wind power plant, 411i, 421i, 431i ... Wind power generation system, 412, 422, 432 ... Transformer for interconnection, 413, 423, 433 ... Voltage detector, 414, 424, 434 ...・ Current detector, 50 ... Solar power plant control system, 51 ... Solar power plant, 511 ... Solar panel, 512 ... Interconnection transformer, 513 ... Voltage detection 514 ... Current detector, 515 ... Power converter for interconnection, 6 ... Control system for renewable energy power plants, 7 ... Communication line

Claims (15)

A control system for a renewable energy power generation facility that has a plurality of renewable energy power generation facilities that generate power using renewable energy sources and that controls a renewable energy power generation facility that is operated in conjunction with an electric power system. And
When the absolute value of the output controllable amount of the renewable energy power generation facility falls below the absolute value of the output control target amount, the output control amount of the renewable energy power generation facility that has not reached the upper limit of the output controllable amount is increased. A control system for a renewable energy power generation facility characterized by performing control. A control system for a renewable energy power generation facility according to claim 1,
When the absolute value of the output controllable amount of the renewable energy power generation facility is less than the absolute value of the output control target amount, the output controllable amount and the output control target amount in each of the renewable energy power generation facilities are compared. A control system for a renewable energy power generation facility, wherein whether or not to change the output of each of the renewable energy power generation facilities is determined. A control system for a renewable energy power generation facility according to claim 2,
When the output of the renewable energy power generation facility needs to be changed, the change value of the output is calculated. A control system for a renewable energy power generation facility according to any one of claims 1 to 3,
The output control target amount in the renewable energy power generation facility is determined based on a control constant predetermined in the renewable energy power generation facility and frequency fluctuation information of the power system. Control system. A control system for a renewable energy power generation facility according to claim 4,
The control system for a renewable energy power generation facility, wherein the frequency fluctuation information is obtained from a first frequency fluctuation calculating means for calculating a first frequency fluctuation. A control system for a renewable energy power generation facility according to claim 5,
The control system for a renewable energy power generation facility, wherein the first frequency fluctuation is a frequency fluctuation with a period of several seconds to several tens of seconds. A control system for a renewable energy power generation facility according to claim 5 or 6,
The control system for a renewable energy power generation facility, wherein the frequency fluctuation information is obtained from a second frequency fluctuation calculating means for calculating a second frequency fluctuation having a time period different from the first frequency fluctuation. A control system for a renewable energy power generation facility according to claim 7,
The control system for a renewable energy power generation facility, wherein the second frequency fluctuation is a frequency fluctuation with a period of several minutes to several tens of minutes. A control system for a renewable energy power generation facility according to any one of claims 1 to 8,
The renewable energy power generation facility or the output controllable amount of the renewable energy power generation facility is estimated using the strength of the renewable energy source and the output characteristics of the renewable energy power generation facility. Power generation facility control system. A control system for a renewable energy power generation facility according to claim 9,
A control system for a renewable energy power generation facility, wherein the intensity of the renewable energy source is obtained from a measured value. A control system for a renewable energy power generation facility according to claim 9,
A control system for a renewable energy power generation facility, wherein the intensity of the renewable energy source is obtained from a predicted value. A control system for a renewable energy power generation facility according to any one of claims 1 to 11,
Renewable energy power generation comprising a function of notifying at least one of an output controllable amount of the renewable energy power generation facility and an output controllable amount of the renewable energy power generation facility to a control system of the power system Facility control system. A control system for a renewable energy power generation facility according to any one of claims 1 to 12,
The renewable energy power generation facility is a renewable energy power generation device,
The control system for a renewable energy power generation facility, wherein the renewable energy power generation facility is a renewable energy power plant. A control system for a renewable energy power generation facility according to any one of claims 1 to 12,
The renewable energy power generation facility is a renewable energy power plant,
The control system for a renewable energy power generation facility, wherein the renewable energy power generation facility is a group of renewable energy power plants. A control system for a renewable energy power generation facility according to any one of claims 1 to 14,
The control system for a renewable energy power generation facility, wherein the renewable energy power generation facility is a wind power generation facility or a solar power generation facility.