JP5647329B2 - New energy power plant group control system and control method thereof - Google Patents

Description

  The present invention relates to a technique for adjusting output power and voltage of a new energy power plant group composed of a plurality of wind power plants and solar power plants connected to an electric power system.

  In recent years, natural resources such as wind and sunlight have been used as countermeasures against the emergence of global environmental issues such as global warming and acid rain, the depletion of fossil resources such as oil and coal, and ensuring energy security. Introduction of power generation facilities such as wind power generation and solar power generation using energy is progressing. Of these, wind power generation has reached a technically practical stage and is already in commercial operation in Japan and overseas. In the future, in order to reduce installation costs and improve power generation efficiency, With the increase in single-unit capacity and wind farms, the scale of power generation facilities using natural energy is expected to increase.

  As for solar power generation, as one of effective means for expanding the amount of introduction, there is an increasing expectation for a large-scale power plant (so-called mega solar) whose output power is several MW or more. Many construction plans have been announced, including those in Japan, where there are already examples of megasolar installations, particularly in Europe, and the introduction of megasolars is expected to progress further in the future. Furthermore, under the initiative of the government, the purchase price of photovoltaic power generation purchased by electric power companies is set higher, and so on, so that the spread of photovoltaic power generation to each home is promoted.

  In such wind power generation and solar power generation, the power generation output fluctuates depending on the wind speed or the intensity of solar radiation. Therefore, from the viewpoint of stable operation of the total power system including commercial power systems and private power generation systems, It is necessary to reduce the influence of fluctuations in power generation output at many natural energy power plants on the power quality (voltage, frequency) of the power system. For example, in Spain, where the ratio of the amount of wind power generation is extremely high at 10% or more, power system control is performed to appropriately control the power generation output while remotely monitoring a plurality of wind power plants of 10 MW or more. Techniques relating to such wind power generation and power system control have been reported (for example, see Non-Patent Document 1). In addition, by combining adjustment power supplies and storage batteries with variable output power to multiple natural energy power supplies, the supply and demand on the natural energy power supply side is not dependent on the supply and demand adjustment capabilities of the commercial power system on the power company side. A technique for performing the adjustment is also disclosed (for example, see Patent Document 1).

  Wind power generation and solar power generation using natural energy such as wind power and solar power are called new energy power generation by NEDO (New Energy and Industrial Technology Development Organization). In the present invention, natural energy power generation such as wind power generation and solar power generation is referred to as new energy power generation.

JP 2006-204081 A

Japan Wind Power Association: “Wind Power Generation and Power System Control in Spain” report dated January 30, 2009, http://jwpa.jp/pdf/50-05spain090130.pdf

  However, the technology disclosed in the above-mentioned prior art documents is a variation in the power output of a new energy power plant caused by a steady change in weather conditions, that is, a steady change in wind speed and a steady change in solar radiation conditions ( For example, control is performed so as to maintain a power supply / demand balance in a specific area against a relatively gradual fluctuation in power generation output (several tens of percent of the rated output). On the other hand, in the new energy power plant, in addition to the steady output fluctuations described above, the power plant itself will be shut down due to sudden changes in weather conditions and system disturbances, resulting in large and sudden changes in power generation output. There is.

  For example, in a wind power plant, if the wind speed further increases beyond a preset maximum wind speed, the operation of the wind power plant is stopped to protect the equipment. Such emergency shutdown is called cutout control, and the wind speed threshold at which a wind farm is shut down is generally determined by the mechanical load acting on the blades of the wind turbine blades. Is set to a level that does not reach the fatigue limit. When the operation of the wind power plant is stopped by such cutout control, the power generation output is suddenly narrowed from the rated output to zero, and a large output sudden change occurs. In addition, a new energy power plant may be in an output stopped state due to a system disturbance such as an instantaneous voltage drop.

  If such a phenomenon occurs not only in one wind power plant but also in a plurality of wind power plants, a large sudden output change may occur in the entire area. In the techniques of Patent Document 1 and Non-Patent Document 1, in order to maintain the frequency on the power system side, an increase in power reserve reserve or to absorb an output change equivalent to 100% of the rated power A power adjustment device such as a storage battery having the same capacity as the power generation output of the power plant is required.

  That is, as a first problem, when the new energy power plant itself stops operation due to a sudden change in weather conditions or the influence of grid disturbance, the power supply / demand balance on the power grid side is performed using a separately prepared power adjustment device. There must be. Therefore, if there are more new energy power plants that cause shutdown, the total power generated by the power conditioner must inevitably be increased, resulting in a power conditioner that adjusts the power generation output. Equipment costs will rise.

  In addition, the voltage fluctuation problem in the power system is a phenomenon in which voltage fluctuations occur not in the entire area but in the local grid unit, so even if output fluctuations are suppressed in the entire area, each new energy power plant Voltage fluctuation occurs at the grid connection point. No solution is described in the above-mentioned Patent Document 1 and Non-Patent Document 1 for such a phenomenon of voltage fluctuation. After all, stable operation can be achieved without depending on the voltage adjustment function on the power system side. The proper voltage to continue cannot be maintained. In other words, as a second problem, when the new energy power station itself stops operation due to a sudden change in weather conditions or the influence of system disturbance, it absorbs voltage fluctuations in the power system if it does not depend on the voltage adjustment function on the power system side. Can not do it.

  The present invention has been made in view of such problems, and a new energy that can appropriately control the power system even when the output of the new energy power plant suddenly changes due to a sudden change in weather conditions or a suspension of operation when the system is disturbed. It is an object of the present invention to provide a power plant group control system and a control method therefor.

In order to achieve the above object, a control system for a new energy power plant according to the present invention is a new power plant that is connected to an electric power system and includes a plurality of wind power plants and solar power plants whose power generation output varies according to weather conditions. An energy power station group, an output adjustment device capable of controlling the power generation output, a power supply command station for controlling the supply and demand balance of the power system, and a substation for adjusting the voltage and reactive power of the power system, is connected via a line, said a control system of the new energy plant group to adjust the power output of the renewable energy power plant group and the output adjusting device, voltage management target value transmitted from the previous SL substation and Using the voltage measurement information of a plurality of new energy power plants and the voltage adjustment sensitivity due to reactive power at the grid interconnection points of the plurality of new energy power plants calculated sequentially, the reactive power And reactive power command computing means for computing a command, on the basis of the voltage management target value and to said voltage measuring information, and the voltage change due to the reactive power and its the reactive power by the grid interconnection point of said plurality of new energy power plant Correlation coefficient calculation means for calculating the correlation coefficient, and voltage adjustment sensitivity calculation means for calculating the voltage adjustment sensitivity based on the correlation coefficient calculated by the correlation coefficient calculation means. The command calculation means calculates a reactive power command using the voltage adjustment sensitivity calculated by the voltage adjustment sensitivity calculation means .

  The new energy power plant group control method according to the present invention includes a new energy power plant group composed of a plurality of wind power plants and solar power plants that are connected to an electric power system and whose power generation output varies according to weather conditions. An output adjustment device capable of controlling the power generation output, a power supply command station for controlling the supply and demand balance of the power system, and a substation for adjusting the voltage and reactive power of the power system via a communication line And a control method for a new energy power plant group of a control system that adjusts the power generation output of the new energy power plant group and the output adjusting device, the voltage management target value transmitted from the substation and a plurality of new Calculating a correlation coefficient between the reactive power at the grid interconnection points of the plurality of new energy power plants and the voltage change caused by the reactive power based on the voltage measurement information of the energy power plant. A second step of calculating a voltage adjustment sensitivity by the reactive power based on the correlation coefficient calculated in the first step, and a voltage adjustment by the reactive power calculated in the second step And a third step of calculating a reactive power command using sensitivity.

  According to the control system for a new energy power plant group according to the present invention, a new energy power generation capable of appropriately controlling the power system even when the output of the new energy power plant is suddenly changed due to a sudden change in weather conditions or a suspension of operation when the system is disturbed. A group control system and a control method thereof can be provided.

It is a block diagram which shows schematic structure of the new energy power plant group which concerns on one Embodiment of this invention. It is a block diagram which shows the function of the control system shown in FIG. It is a flowchart which shows the flow of the process which the control system shown in FIG. 2 performs. It is a characteristic view showing the relationship between the wind speed and power generation output of a general wind power generator. It is a characteristic view which shows an example of the electric power generation output characteristic when cutout stop generate | occur | produces intermittently in a wind power generator. It is a flowchart regarding the prediction process of the output sudden change of the wind power plant which the control system which concerns on embodiment of this invention performs. It is a characteristic figure showing the relation between the wind speed and power generation output for explaining operation of output sudden change prediction in the output adjustment function of this embodiment. It is a characteristic view which shows the correlation coefficient of the electric power generation output between two wind power plants. It is a flowchart regarding the output control process which the control system which concerns on embodiment of this invention performs. It is a typical graph of the electric power generation output for demonstrating the output control operation | movement of an output adjustment function. It is a flowchart regarding the adjustment sensitivity calculation process of the reactive power and voltage which the voltage adjustment function of the control system which concerns on embodiment of this invention performs. It is a typical graph for demonstrating the adjustment sensitivity calculation operation | movement of the reactive power of the voltage adjustment function which concerns on embodiment of this invention. It is a typical graph of the connection point voltage for demonstrating the predominance of the voltage adjustment operation | movement which concerns on embodiment of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a control system for a new energy power plant group according to the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.

  FIG. 1 is a configuration diagram showing a schematic configuration of a new energy power plant group according to an embodiment of the present invention. In FIG. 1, a new energy power plant group G composed of wind power plants 5A, 5B, 5C and solar power plants 6A, 6B whose power generation output varies depending on weather conditions, and each new energy power plant group G. Output adjustment centers 7 for adjusting the power generation outputs of the energy power plants 5A, 5B, 5C, 6A, 6B (5A-6B) are respectively connected via power receiving facilities 53A, 53B, 53C, 63A, 63B, 73. It is connected to the power transmission line 2 of the power system 1. The power system 1 may be a commercial power system of an electric power company, or may be a power system unique to private power generation, but the following description assumes a commercial power system.

  The power generation output of each of the new energy power plants 5A to 6B is supplied to a consumer (not shown) connected to the power system 1 via the power transmission line 2. These new energy power plants 5A to 6B do not need to be concentrated in a specific area, and may be distributed in locations where the wind conditions or solar radiation conditions are good.

  In addition, as a new energy power plant group G, only wind power plants 5A, 5B, 5C and solar power plants 6A, 6B are shown in FIG. 1 for simplicity, but in reality, a larger number of power plants are connected. It is assumed that Moreover, only the minimum element required for description of this embodiment is described as an element which comprises new energy power station 5A-6B and the electric power grid | system 1. FIG.

  The wind power plants 5A, 5B, 5C (5A to 5C) and the solar power plants 6A, 6B that constitute the new energy power plant group G are connected to the control system 8 that controls the new energy power plant group G and a communication line (communication). Network) 92, and input / output of information between the new energy power plants 5 </ b> A to 6 </ b> B and the control system 8 is performed via the communication line 92. The control system 8 also includes a power supply command station 4 for controlling the supply and demand balance between the demand power and the power generated by a large-scale central power plant (not shown) such as thermal power generation or nuclear power generation in the power system 1, the power system 1. Are connected to the substations 31, 32, 33, 34 (31 to 34) having a function of appropriately maintaining the voltage and the reactive power, and the weather information server 10 through communication lines 91 and 92.

  The wind power plants 5A to 5C constituting the new energy power plant group G are wind power generation system groups 51A, 51B, and 51C (51A to 51C) each including a plurality of windmills, a generator, and a power converter for interconnection. And measurement of electrical characteristics and weather characteristics (wind speed, wind direction, temperature, etc.) such as the power generation output of those wind power generation system groups 51A to 51C, the voltage at the grid connection point, and the output adjustment command transmitted from the control system 8 And measurement / control terminals 52A, 52B, and 52C having a function of transmitting reactive power adjustment commands to individual wind power generation systems.

  Similarly, the solar power plants 6A and 6B include solar power generation system groups 61A and 61B each including a plurality of solar panels and interconnection power converters, and the solar power generation system groups 61A, 61B power generation output, measurement of electrical characteristics such as grid connection voltage and meteorological characteristics (wind speed / direction, temperature, solar radiation, etc.) and reactive power adjustment commands transmitted from the control system 8 for individual photovoltaic power generation It is constituted by measurement / control terminals 62A and 62B having a function of transmitting to the system.

  The output adjustment center 7 includes an output adjustment device 71 including a power generation device such as a gas turbine generator and a diesel generator capable of controlling the power generation output, or a power storage device such as a storage battery, and the power generation output of the output adjustment device 71. The control system 8 includes a measurement / control terminal 72 having a function of measuring electrical characteristics and transmitting an output adjustment command and a reactive power adjustment command transmitted from the control system 8 to the output adjustment device 71. In FIG. 1, the control system 8 is provided in the output adjustment center 7. However, the control system 8 may exist independently in the system constituting the new energy power plant group G.

  The control system 8 includes an output adjustment command from the power supply command station 4, a target voltage command from the substations 31 to 34, the wind power plants 5 </ b> A to 5 </ b> C, the solar power plants 6 </ b> A and 6 </ b> B, and the output adjustment device 71. Based on the measurement information collected via the measurement / control terminals 52A, 52B, 52C, 62A, 62B, 72 (52A to 72), a control command for performing output adjustment and voltage adjustment is calculated, and the calculated control is performed. It has a function to transmit the command to the new energy power plants 5 </ b> A to 6 </ b> B and the output adjustment device 71 of the output adjustment center 7.

  FIG. 2 is a block diagram showing functions of the control system 8 shown in FIG. In FIG. 2, the control system 8 includes a control arithmetic unit 81 that calculates a control command to be transmitted to the new energy power plants 5A to 6B and the output adjustment unit 71 of the output adjustment center 7, and an input for an operator to input an operation command. A device 82, a display device 83 for an operator to check the operation status, a communication device 84 for controlling transmission and reception of control commands and measurement information, and measurement information of the new energy power plants 5A to 6B and the output adjustment device 71 And a data storage device 85 that stores a history of control commands and the like.

  The communication device 84 performs information communication with the new energy power plants 5A to 6B, the output adjustment center 7, the power supply command station 4, and the substations 31 to 34 via the communication lines 91 and 92. The control arithmetic device 81 includes an output adjustment function 811 and a voltage adjustment function 812.

  The output adjustment function 811 in the control arithmetic unit 81 includes an output sudden change predicting unit (output sudden change predicting means) 8111 for predicting a power plant whose output changes suddenly among the new energy power plants 5A to 6B, and its generation time. Based on the prediction result of the sudden change predicting unit 8111, the power plant does not change suddenly, and an output control calculating unit (power generation output adjusting means) 8112 that calculates the output adjustment command value of the output adjusting device 71.

  Moreover, the voltage adjustment function 812 in the control arithmetic unit 81 includes a correlation coefficient calculation unit (correlation coefficient calculation means) 8121 for evaluating the correlation between reactive power and voltage in each of the new energy power plants 5A to 6B. Each of the new energy power plants 5A to 5A is configured using a voltage adjustment sensitivity calculation unit (voltage adjustment sensitivity calculation means) 8122 for calculating a voltage adjustment sensitivity due to reactive power and the adjustment sensitivity calculated by the voltage adjustment sensitivity calculation unit 8122. The reactive power command calculation unit (reactive power command calculation means) 8123 for calculating the reactive power command value of 6B is configured.

  Next, the process flow of the control system 8 will be described. FIG. 3 is a flowchart showing a flow of processing performed by the control system 8 shown in FIG. Therefore, the processing flow of the control system 8 will be described along the flow of the flowchart of FIG. 3 with reference to FIGS. 1 and 2.

  First, in process S1, (1) while reading the measurement information of the new energy power plants 5A to 6B and the output adjustment device 71, (2) reading the system command information of the power supply command station 4 and the substations 31 to 34 Do. That is, (1) Electrical characteristics periodically measured and transmitted by the respective measurement / control terminals 52A to 72 installed in the wind power plants 5A to 5C, the solar power plants 6A and 6B, and the output adjustment device 71 The data and the weather characteristic data transmitted from the weather information server 10 are read from the data storage device 85, and (2) the output target command value periodically transmitted from the power supply command station 4 and periodically from the substations 31 to 34 Is read from the data storage device 85.

  Next, in process S2, an interrupt output is applied to the operation / stop information of the new energy power plants 5A to 6B. That is, regardless of the measurement / transmission cycle periodically performed in the new energy power plant group G, when the operation / stop state of each of the new energy power plants 5A to 6B changes, the respective measurement / control terminals 52A to 62B The information on the operation / stop state transmitted irregularly from is read and output as an interrupt signal to the output adjustment process S3 and the voltage adjustment process S4.

  Here, in the output adjustment processing S3, a new energy power plant whose output changes suddenly next is predicted from the new energy power plants 5A to 6B based on the operation / stop state information of the new energy power plants 5A to 6B (processing). S31), an output adjustment command value to be transmitted to each of the new energy power plants 5A to 6B and the output adjustment device 71 is calculated based on the result of the output sudden change prediction (processing S32). Further, the output adjustment command value calculated in the process S32 is transmitted to the new energy power plants 5A to 6B and the output adjustment apparatus 71 via the communication device 84 (process S33).

  In the voltage adjustment process S4, the voltage adjustment sensitivity ΔV / ΔQ is calculated using the correlation between the voltage at the grid connection point and the reactive power in the new energy power plants 5A to 6B (process S41). ΔV is a change in voltage, and ΔQ is a change in reactive power. Furthermore, the voltage deviation between the voltage measurement value of each new energy power plant 5A-6B and the voltage target value of each new energy power plant 5A-6B transmitted from the substations 31-34 is calculated (processing S42). (In other words, the reactive power adjustment command value of each power plant is calculated using the voltage adjustment sensitivity and the voltage deviation (processing S43), and the calculated reactive power adjustment command value is transmitted to the new energy power generation via the communication device 84. The data is transmitted to the stations 5A to 6B and the output adjusting device 71 (processing S44).

  The sudden change in output of the new energy power plants 5A to 6B referred to here is, as described above, a large equivalent to the rated output in a short time due to a sudden change in weather conditions or a disruption of the system when the new energy power plants 5A to 6B are shut down. It refers to a phenomenon in which output fluctuations occur, and assumes a case where an operation stop state occurs in a chain manner at a plurality of new energy power plants 5A to 6B. As a factor of such a sudden change in output, in wind power generation, a cutout stop accompanying an increase in wind speed can be mentioned.

  FIG. 4 is a characteristic diagram showing the relationship between the wind speed and the power generation output of a general wind power generator. The horizontal axis indicates the wind speed (m / s), and the vertical axis indicates the power generation output (%). FIG. 5 is a characteristic diagram showing an example of power generation output characteristics when cutout stops occur intermittently in the wind turbine generator, with the horizontal axis representing time (hours) and the left vertical axis representing wind speed (m / s). ), And the right vertical axis indicates the power generation output (%).

  As shown in FIG. 4, generally, a wind power generation system starts wind power generation when the wind speed exceeds 3 m / s (cut-in wind speed). In addition, the electric power generation output P of a wind power generation system is calculated | required using following Formula (1).

P = (1/2) · ρ · A · v ³ · η (1)
Here, P is the power generation output (W), ρ is the air density (kg / m ³ ), A is the wind receiving area (m ² ),
v is the wind speed (m / s), and η is the power generation efficiency (%).

  Therefore, as shown in FIG. 4, in the wind power generation system, the power generation output P increases in proportion to the cube of the wind speed v until the wind speed v reaches the rated value 12 m / s. When the wind speed v further increases to 12 m / s or more, the wind power generation system performs rated operation so as to maintain the rated output by controlling the rotation frequency. However, when the wind speed v exceeds 25 m / s (cutout wind speed), the operation is stopped in order to protect the equipment of the wind power generation system.

  In this way, when the wind speed v instantaneously exceeds 25 m / s and the cutout stop occurs in the wind power generation system, as shown in FIG. 5, the power generation output corresponding to the rating becomes zero in a short time. At this time, although depending on the wind conditions, once the operation of the wind power generation system is stopped, the stopped state is continued for about several tens of minutes or more. When such a cut-out phenomenon occurs in a chain among a plurality of wind power plants 5A to 5C, a large output change that affects the adjustment reserve capacity of the power system results in such a power output change as the power system 1. It is necessary to secure the reserve for adjustment so that it can cope with the situation.

  On the other hand, in solar power generation, the amount of solar radiation changes suddenly due to the movement of clouds, and the power generation output may change from the power generation output corresponding to the rating to near zero. However, in the case of photovoltaic power generation, the power generation output generally returns in a few minutes, so it is unlikely that a large decrease in output will occur simultaneously or chained at multiple solar power plants. Conceivable.

  Therefore, it is considered effective to predict the change in output due to a sudden change in weather conditions with the cut-out stop of the wind power plants 5A to 5C as an object. In addition, due to system disturbance such as instantaneous voltage drop, there is a possibility that the operation is stopped in units of the new energy power plants 5A to 6B regardless of wind power generation or solar power generation. In this case, a large output change occurs.

  Next, with reference to the flowchart of FIG. 6, the specific processing content of each part in the overall processing flow of the control system shown in FIG. 3 will be described. FIG. 6 is a flowchart relating to a prediction process of a sudden change in output of a wind power plant performed by the control system according to the embodiment of the present invention. In addition, this process has shown the flow of the process which estimates new energy power station 5A-6B from which an operation stop is anticipated, and its generation | occurrence | production time.

  In FIG. 6, when the control system 8 acquires the measurement information of the new energy power plants 5A to 6B, first, in process S11, it is determined whether or not there is a power plant that has stopped operating among the new energy power plants 5A to 6B. . Here, if there is no power plant that has stopped operating among the new energy power plants 5A to 6B (S11 → None), the output sudden change prediction process is terminated in order to perform normal output adjustment control (END). That is, the processes S32 and S33 in the output adjustment process (process S3) in the flowchart of FIG. 3 are executed.

  On the other hand, in process S11, if there is a power station that has stopped operating among the new energy power stations 5A to 6B, process S12 is executed. In process S12, the presence or absence of occurrence of an instantaneous voltage drop (system disturbance occurrence) is determined from the operation history of the protection relay of the power plant that is stopped and the weather characteristic data. Here, when it is determined that the stopped power plant is stopped due to the occurrence of instantaneous voltage drop (system disturbance occurrence) (when system disturbance occurrence is “Yes” in process S12), the power station is stopped in process S13. For example, a power plant in operation located within a radius R (km) from a power plant that is in operation is set as a power plant that may stop among the new energy power plants 5A to 6B, and their predicted occurrence times are set. The instantaneous output change process is finished (END). That is, the processes S32 and S33 in the output adjustment process (process S3) in the flowchart of FIG. 3 are executed.

  On the other hand, if it is determined in the process S12 that the power plant is not stopped due to the occurrence of an instantaneous voltage drop (system disturbance occurrence) (if the system disturbance has not occurred in process S12), the process proceeds to process S14. .

  The process after process S14 assumes the cut-out stop of the wind power plants 5A to 5C, and may stop next from the information on the currently stopped power plant among the wind power plants 5A to 5C. A process for predicting a power plant is performed. That is, the basic idea of the present embodiment focuses on the correlation between the power generation output of the past several hours of the currently stopped power plant among the wind power plants 5A to 5C and the power generation output of the currently operating power plant. The correlation coefficient is calculated while moving the time axis of the power generation output of the currently stopped and currently operating power plants among the wind power plants 5A to 5C. The stop occurrence time is predicted by using the moving time in which it is determined that there is a correlation coefficient and becomes the maximum.

  That is, the specific process after process S14 is as follows. Of the wind power plants 5A to 5C, the power generation output from the current time Tp of the power plant that is stopped to the past time To before the past T hours is substituted into Ps (t) (processing S14). Note that Ps (t) is the total power output up to the past T hours before the currently stopped power plant among the wind power plants 5A to 5C.

  Similarly, the power generation output from the current time (Tp-δT · j) of the operating power plant among the wind power plants 5A to 5C to the past time (To-δT · j) before the past T hours is represented by Po (ta ) Is substituted for (step S15). Note that Po (ta) is the total power output up to the past T hours before the currently operating power plant among the wind power plants 5A to 5C. Further, δT · j is a value obtained when the current time Tp (or past time To) of the operating power plant among the wind power plants 5A to 5C is shifted by j times in the past in δT time increments (for example, every 5 minutes). “Shift time”. Then, a correlation coefficient CRso_j between the generated power output Ps (t) of the stopped wind power plant and the generated power output Po (ta) of the operating power plant among the wind power plants 5A to 5C is calculated (processing S16). .

  Next, the maximum value CRmax of the correlation coefficient CRso_j calculated in process S16 and the time shift amount (shift time) ΔT at that time are obtained (process S17). Here, the processing from processing S15 to processing S17 is repeatedly performed while shifting the power generation output of the operating power plant among the wind power plants 5A to 5C in increments of δT in the past. That is, for all the power plants in operation among the wind power plants 5A to 5C, the step δT is repeated from j = 1 to n to execute the processing S15 to S17 (processing S17a).

That is, n is the number of shifts of the step time δT, and is a natural number represented by the following equation (2).
n = T / δT (2)
However, T is the time between the past time To and the current time Tp, and δT is the step time.

  Next, it is determined whether or not the maximum value CRmax of the correlation coefficient CRso_j is larger than a predetermined threshold ε (processing S18). If CRmax is larger than the predetermined threshold ε (CRmax> ε) (processing S18). In the case of Yes), it is determined that there is a correlation between the power generation output Ps (t) of the stationary power plant among the wind power plants 5A to 5C and the power generation output Po (ta) of the operating power plant. . That is, among the wind power plants 5A to 5C, the corresponding operating power plant is determined as a power plant whose power generation output may change suddenly, and the shift time ΔT is added to the current time Tp to obtain (Tp + ΔT). The predicted generation time of the power plant where the power generation output may change suddenly is set (processing S19). New energy power plants 5A to 6B (wind power plants 5A to 5C) whose generation output may change suddenly by performing the above processing for all the operating wind power plants 5A to 5C, and their generation times Can be predicted.

Next, an exemplary operation of steps S14 to S17 in FIG. 6 will be described in detail with reference to FIGS. FIG. 7 is a characteristic diagram showing the relationship between the wind speed and the power generation output for explaining the operation of the output sudden change prediction in the output adjustment function of this embodiment, and (a) shows the wind speed and the power generation output of the wind power plant 5A. (B) shows the relationship between the wind speed and the power generation output of the wind power plant 5B, and (c) shows the relationship between the wind speed and the power generation output of the wind power plant 5C. It represents wind speed and power generation output. However, the unit is represented by the unit method (pu) normalized by the standard wind speed and the power generation output.
FIG. 8 is a characteristic diagram showing the correlation coefficient between the two wind power plants, with the horizontal axis representing the shift time and the vertical axis representing the correlation coefficient.

  As shown in FIGS. 7 (a) and 7 (b), the wind power plant 5A and the wind power plant 5B have relatively strong winds, and the wind speed of each power plant exceeds the rating and exceeds or returns to the cutout wind speed. Accordingly, a phenomenon occurs in which the power generation output decreases from the rated value to zero.

  That is, in the wind power plant 5B, the same wind speed phenomenon as that of the wind power plant 5A occurs with a delay of the time difference ΔT. Further, at the current time Tp, the wind power plant 5A stops power generation because it exceeds the cut-out wind speed. On the other hand, at the current time Tp, the wind power plant 5B is performing the power generation operation because it does not exceed the cut-out wind speed. However, it is predicted that the wind power plant 5B will stop generating power after exceeding the cut-out wind speed after the time difference ΔT. In other words, when the wind power plant 5B shifts the time by the time difference ΔT, it is predicted that the same phenomenon as that of the wind power plant 5A occurs with a correlation with the wind power plant 5A.

  In addition, as shown in FIG. 7C, the wind power plant 5C continues the rated power generation output from the past time To to the current time Tp because the wind speed is higher than the rated wind speed but has not reached the cutout wind speed. Sending out. That is, the wind power plant 5C has no correlation with the wind power plant 5A even if the time is shifted.

  At this time, if the correlation coefficient is calculated while shifting the time of the power generation output of the wind power plant 5B and the wind power plant 5C with respect to the power generation output of the wind power plant 5A according to the processing contents described in the flowchart of FIG. FIG. 8 is a characteristic diagram showing the relationship between the time difference and the correlation coefficient.

That is, as shown in FIG. 8, since the wind power plant 5A and the wind power plant 5C are uncorrelated, the correlation coefficient is much less than the threshold value ε, whereas the wind power plant 5A and the wind power plant 5B There is a time difference exceeding a threshold ε (for example, 0.7), and the shift time at which the correlation coefficient is maximum is defined as a time difference ΔT between the power generation outputs of the wind power plant 5A and the wind power plant 5B. That is, the correlation coefficient between 5A and 5B is maximized when the time difference ΔT is set.
Note that the wind power plants 5A to 5C are denoted as wind power plants A, B, and C in FIG.

  FIG. 9 is a flowchart regarding output control processing performed by the control system according to the embodiment of the present invention. Therefore, the processing content of the output control calculation will be described using the flowchart of the output control processing performed by the control system 8 shown in FIG. In FIG. 9, first, it is determined whether or not output adjustment is necessary for the sudden output change by using the output sudden change power plant described in the flowchart of FIG.

  Here, when the output adjustment for the sudden output change is unnecessary (No in Step S21), the output command value is calculated by the normal output target value control (Step S22). The normal output target value control means that the deviation of the new energy power plant group G is minimized so that the combined output of the new energy power plant group G becomes the target value commanded from the power supply command station 4. The output limit value and the output of the output adjustment device 71 are adjusted.

  On the other hand, when the process of the output adjustment for the output sudden change is necessary in the determination of the process S21 (necessary in the process S21), the power plant that is predicted to have a sudden output change among the new energy power plants 5A to 6B. An output restriction pattern, that is, an output restriction value at time t is generated using the predicted output sudden change time (process S23). Specifically, the output limit value at time t is set by the following equation (3).

Pi (t) = (ts−t) (Pi (tp) / (ts−tp)) (3)
However, i is the number of the power plant that is predicted to have a sudden output change among the new energy power plants 5A to 6B, ts is the predicted output sudden change occurrence time, tp is the current time, Pi (t) is an arbitrary time t , Pi (tp) is the power generation output of the i-th power plant at the current time.

Next, a combined output restriction pattern in the new energy power plant group G in the entire area is generated by the following equation (4) (processing S24).
P (t) = ΣPi (t) (4)

  Here, since the combined output of the entire area is reduced by the output limit value P (t) obtained by the equation (4), the output is made up to compensate for the insufficient output of the new energy power plants 5A to 6B. The power generation output that can be increased (the power plants other than the power plant that is stopped and whose output sudden change is predicted) and the power generation output of the output adjustment device 71 are increased. That is, a combined output increase pattern in the entire area is generated (process S25), and a power plant capable of increasing the output and the output adjustment device 71 are extracted from the entire area (process S26). And an output increase pattern is produced | generated based on the extracted power station and the output adjustment apparatus 71 (process S27).

  In other words, in the processes S25 to S27, power plants that can increase the output are extracted from the new energy power plants 5A to 6B, and the output limit value P (t) is distributed to these to be used as an output adjustment command. For power plants capable of increasing output, power plants whose output at the current time is smaller than the rated output are extracted from power plants that are determined to have no possibility of sudden change in output. As a method of allocating the output increase amount, for example, a method of sequentially allocating from a power plant having a large output increase amount is adopted, and the priority order for allocating the power generation output of the output adjustment device 71 to the shortage output is the last.

  Next, of the new energy power plants 5A to 6B, with regard to the stopped power plants, it is determined whether or not there is a power plant whose output has been resumed due to wind conditions during the processes S21 to S27 (process S28), and the operation is resumed. If there is a power station that has been operated (Yes in process S28), the processes in steps S21 to S27 are performed again. If there is no power station that has been restarted (no process in S28), the above-described processes S23 and S27 are performed. The output adjustment command (output restriction command and output increase command) obtained in step S5 is transmitted to each of the new energy power plants 5A to 6B (processing S29). And it returns to process S21 and repeats each above-mentioned process.

  FIG. 10 is a schematic graph of the power generation output for explaining the output control operation of the output adjustment function. That is, FIG. 10 (a) shows the power generation output during the output adjustment operation according to the prior art that does not take into account the sudden change in output of the new energy power plants 5A to 6B, and FIG. The power generation output at the time of the output adjustment operation when considering the sudden output change of the energy power plants 5A to 6B is shown.

  As shown in FIG. 10 (a), in the conventional technology that does not take into account the sudden change in output of the new energy power plants 5A to 6B, the power generation of the entire area occurs at the moment when the sudden change (rapid decrease) in the power output occurs at a certain power plant. The output has dropped rapidly. On the other hand, as shown in FIG. 5B, according to the embodiment of the present invention in which the sudden change in output of the new energy power plants 5A to 6B is predicted, the sudden change in output is predicted at the current time Tp before the sudden change in output occurs. Therefore, the power generation output can be switched by the power plant that does not suddenly change the output and the output adjustment device 71 by the occurrence prediction time Ts at which the sudden output change is predicted. Therefore, it is possible to reduce the influence of the sudden output change and maintain the combined power generation output of the entire area at the target value.

  That is, as shown in FIG. 10B, the power plant whose output does not change suddenly as the power generation output Pi (t) of the power plant i whose output suddenly changes after the current time Tp at which the sudden output change is predicted decreases. Since the power generation output P (t) of the output adjustment device 71 increases, the combined power generation output of the entire area continues to maintain the target value after the predicted output time Ts of the sudden output change.

  Next, the processing contents of the voltage adjustment function shown in steps S41 to S43 in the flowchart of FIG. 3 will be specifically described with reference to the flowchart of FIG. FIG. 11 is a flowchart regarding reactive power and voltage adjustment sensitivity calculation processing performed by the voltage adjustment function of the control system according to the embodiment of the present invention.

  In the process of the flowchart of FIG. 11, in addition to suppressing the voltage fluctuation at the grid connection point caused by the output fluctuation of the new energy power plants 5A to 6B itself, in order to properly maintain the voltage profile of the power grid, A process of maintaining the average voltage at the target voltage transmitted from the substations 31 to 34 is performed.

  That is, the voltage fluctuation generated by the output fluctuation of the new energy power plants 5A to 6B can be suppressed by setting the ratio of the reactive power to the active power at an optimum ratio obtained from the system impedance. The ratio of reactive power to active power can be changed by changing the phase of voltage and current with an inverter, or changing the ratio of capacitors (C) and inductance (L) with a phase adjuster to change the impedance. It can be set to a desired value.

  In addition, in order to set the average voltage of the new energy power plants 5A to 6B to the target value, it is necessary to suppress the influence of the voltage change due to factors other than the power generation output, but the invalidity output from the new energy power plants 5A to 6B. By adjusting the level of the average value of power, the average voltage at the grid connection point can be adjusted. Therefore, in this embodiment, the reactive power Q adjusted by the new energy power plants 5A to 6B is obtained by the following equation (5).

Q = a · P + Q _A (5)
Where P is the power output of the new energy power plant, Q is the reactive power of the power output of the new energy power plant, Q _A is the average level of reactive power of the power output of the new energy power plant, a is the active power and reactive power The proportionality constant (= r / x), r is the resistance component of the system impedance, and x is the reactance component of the system impedance.
Here, the phase of reactive power is positive (plus) in the delay direction as seen from the power system.

Next, in the control system 8, in order to appropriately determine the average level Q _A of reactive power for each of the new energy power plants 5A to 6B, voltage adjustment sensitivity due to reactive power at the grid connection point of each power plant is required. Become. Since the voltage adjustment sensitivity varies depending on the system configuration and the power flow state, it is necessary to control the voltage adjustment sensitivity while sequentially evaluating the voltage adjustment sensitivity. Specifically, the voltage adjustment sensitivity is evaluated by capturing the voltage change when only the reactive power of each of the new energy power plants 5A to 6B changes.

Therefore, in the flowchart of FIG. 11, the control system 8 performs processing for acquiring measurement information and target voltage values of the new energy power plants 5A to 6B from the substations 31 to 34 (processing S50). Next, the reactive power Q _F and the voltage fluctuation V _F after passing through the low-pass filter are extracted from the voltage V and the reactive power Q for a predetermined time (processing S51). Then, the equation (6), calculating the correlation coefficient CRqv reactive power _{Q F} and the voltage variation _{V F} (process S52).

  Next, it is determined whether or not the correlation coefficient CRqv calculated by Expression (6) takes a negative value and whether the absolute value is larger than a threshold value ξ (processing S53). Only when the correlation coefficient CRqv is a negative value and the absolute value is larger than the threshold value ξ (Yes in process S53), the voltage adjustment sensitivities of the new energy power plants 5A to 6B are calculated and updated (process S54). ).

Here, with regard to the process S54 for calculating the voltage adjustment sensitivity of the new energy power plants 5A to 6B, a schematic diagram for explaining the adjustment sensitivity calculation operation of the reactive power of the voltage adjustment function according to the embodiment of the present invention shown in FIG. This will be described using a simple graph. The graph of FIG. 12 are both horizontal axis indicates time t, and the vertical axis represents the reactive power Q _F and voltage variation V _F.

That is, as shown in FIG. 12 (a), reduces the voltage change V _F with an increase of the reactive power Q _F, the reactive power Q _F decreases correlation negative as the voltage variation V _F increases with the If it has, it is considered that the disturbance is not affected, so that the voltage adjustment sensitivity can be calculated correctly. Note that when the reactive power is in a delayed phase as viewed from the power system, the voltage tends to decrease as the delayed reactive power increases.

However, as shown in FIG. 12 (b), if having a correlation, or if positive is no correlation reactive power Q _F and the voltage variation V _F, when the voltage is changed by the influence of the load, etc. Therefore, the voltage adjustment sensitivity due to reactive power of the new energy power plants 5A to 6B cannot be calculated correctly.

Here, the voltage adjustment sensitivity VQsc is obtained as the difference between the reactive power change ΔQ _F obtained as the difference between the maximum value and the minimum value of the reactive power within a predetermined time, and the difference between the maximum value and the minimum value of the voltage fluctuation. Using the change ΔV _F for the voltage fluctuation, calculation is performed using the following equation (7).
VQsc = ΔV _F / ΔQ _F (7)
Such calculation of Expression (7) is performed for all the new energy power plants 5A to 6B, and the voltage adjustment sensitivity VQsc is obtained.

Again, it returns to the flowchart of FIG. A voltage deviation between the target voltage value Vo of the interconnection point transmitted from the substations 31 to 34 and the voltage average value Vave at the current time Tp is calculated (processing S55). Using the voltage deviation (Vave−Vo) calculated in step S55 and the voltage adjustment sensitivity VQsc calculated in step S54, a correction amount Q _L of the reactive power level adjustment value is calculated by the following equation (8). (Process S56).
Q _L = (Vave−Vo) / VQsc (8)

When the correlation coefficient CRqv is not a negative value, or even if it is a negative value, if the absolute value of the correlation coefficient CRqv is less than or equal to the threshold ξ (No in step S53), the current value voltage adjustment sensitivity is used. The correction amount Q _L of the reactive power level adjustment value is calculated by equation (8) (processing S56).

That is, when the voltage average value Vave is higher than the target voltage value Vo, the reactive power that is delayed from the viewpoint of the power system is increased. Conversely, when the voltage average value Vave is lower than the target voltage value Vo, the power Reducing reactive power that is delayed from the viewpoint of the grid. Then, the reactive power level adjustment value correction amount Q _L is transmitted to each of the new energy power plants 5A to 6B (step S57), and the new reactive power plants 5A to 6B side at the present reactive power average level Q _A Add to.

  FIG. 13 is a schematic graph of a connection point voltage for explaining the superiority of the voltage adjustment operation according to the embodiment of the present invention. That is, FIG. 13 shows a graph comparing the voltage adjustment operation according to the present embodiment with the prior art. As shown in FIG. 13, in the prior art, especially when no voltage regulator is installed on the side of the new energy power plants 5A to 6B, the voltage fluctuation is directly caused by the output fluctuation, and the average voltage is adjusted to the target value. I can't do it. On the other hand, according to the present embodiment, voltage fluctuation due to output fluctuation can be suppressed and the average voltage can be controlled to the target value, so that it is possible to contribute to voltage management of the power system.

  As described above, according to the present embodiment, even when the output of the new energy power plants 5A to 6B suddenly changes due to a sudden change in weather conditions or an operation stop at the time of grid disturbance, the power adjustment reserve capacity of the power system is not increased. Since the outputs of the energy power plants 5A to 6B can be maintained at the target values, it is possible to contribute to maintaining a stable frequency of the power system. In addition, the voltage at the grid connection point of the new energy power plants 5A to 6B can be maintained in an appropriate range without imposing a burden on the voltage adjustment facility on the power grid side, which contributes to voltage management of the power grid. It becomes possible.

  Further, in the above, the control system for the new energy power plant group G according to the present invention has been described in detail based on a specific embodiment, but the present invention is not limited to the content of the above embodiment, Various modifications can be made without departing from the scope of the invention.

  According to the present invention, it can be effectively used for grid connection between each power company and the power supply company that operates the new energy power plant group G. It can also be used for interconnection with photovoltaic power generation.

G New energy power plant group 1 Power system 2 Transmission line 3 (31-34) Substation 4 Power supply command station 5 (5A, 5B, 5C) Wind power plant, new energy power plant 51A, 51B, 51C Wind power generation system 52A, 52B, 52C Measurement control terminal 53A, 53B, 53C, 63A, 63B, 73 Power receiving facility 6 (6A, 6B) Solar power plant, new energy power plant 61A, 61B Solar power generation system 62A, 62B Measurement control terminal 7 Output adjustment Center 71 Output adjustment device 72 Measurement control terminal 8 Control system 81 Control operation device 811 Output adjustment function 8111 Output sudden change prediction unit (output sudden change prediction means)
8112 Output control calculation unit (power generation output adjustment means)
812 Voltage adjustment function 8121 Correlation coefficient calculation unit (correlation coefficient calculation means)
8122 Voltage adjustment sensitivity calculation unit (voltage adjustment sensitivity calculation means)
8123 Reactive power command calculation unit (Reactive power command calculation means)
82 Input Device 83 Display Device 84 Communication Device 85 Data Storage Device 9 (91, 92) Communication Line, Communication Network 10 Weather Information Server

Claims (6)

A new energy power plant group consisting of a plurality of wind power plants and solar power plants connected to the power system and whose power generation output fluctuates according to weather conditions, an output regulator capable of controlling the power generation output, and the power system A power supply command station for controlling the supply and demand balance and a substation for adjusting the voltage and reactive power of the power system are connected via a communication line, and the power generation output of the new energy power station group and the output regulator a control system of new energy power plant group to carry out the adjustment,
And voltage management target value transmitted from the previous SL substation, a voltage measurement information of the plurality of new energy power plant, and a voltage adjusting sensitivity by reactive power in a plurality of system interconnection point of the new energy plant to be sequentially calculated Reactive power command calculation means for calculating reactive power command using,
Based on the voltage management target value and the voltage measurement information, a correlation coefficient calculation that calculates a correlation coefficient between a reactive power at a grid interconnection point of the plurality of new energy power plants and a voltage change due to the reactive power Means,
Voltage adjustment sensitivity calculation means for calculating the voltage adjustment sensitivity based on the correlation coefficient calculated by the correlation coefficient calculation means;
With
The reactive power command calculation means calculates a reactive power command using the voltage adjustment sensitivity calculated by the voltage adjustment sensitivity calculation means . In the control system of the new energy power plant group according to claim 1 ,
The voltage adjustment sensitivity calculation means determines whether or not the voltage adjustment sensitivity can be calculated by the reactive power of the new energy power plant based on the correlation between the voltage change calculated by the correlation coefficient calculation means and the reactive power measurement information. A control system for a new energy power plant group, characterized in that The control system for a new energy power plant group according to claim 2 ,
The voltage adjustment sensitivity calculation means calculates the voltage adjustment sensitivity when the correlation coefficient calculated by the correlation coefficient calculation means is a negative value and the absolute value of the correlation coefficient is greater than a threshold value. A new energy power plant control system. A new energy power plant group consisting of a plurality of wind power plants and solar power plants connected to the power system and whose power generation output fluctuates according to weather conditions, an output regulator capable of controlling the power generation output, and the power system A power supply command station for controlling the supply and demand balance and a substation for adjusting the voltage and reactive power of the power system are connected via a communication line, and the power generation output of the new energy power station group and the output regulator A control method for a new energy power plant group of a control system for adjusting
Based on the voltage management target value transmitted from the substation and the voltage measurement information of a plurality of new energy power plants, the reactive power at the grid interconnection points of the plurality of new energy power plants and the voltage change due to the reactive power A first step of calculating a correlation coefficient with
A second step of calculating a voltage adjustment sensitivity due to the reactive power based on the correlation coefficient calculated in the first step;
And a third step of calculating a reactive power command using the voltage adjustment sensitivity based on the reactive power calculated in the second step. In the control method of the new energy power plant group according to claim 4 ,
In the second step, based on the correlation between the voltage change calculated in the first step and the reactive power measurement information, the possibility of calculating the voltage adjustment sensitivity by the reactive power of the new energy power plant A control method for a new energy power plant group, characterized in that In the control method of the new energy power plant group according to claim 5 ,
In the second step, when the correlation coefficient calculated in the first step is a negative value and the absolute value of the correlation coefficient is larger than a threshold value, the voltage adjustment sensitivity by the reactive power is increased. A control method for a new energy power plant group characterized by calculating.

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