JP3461495B2 - Wind power output limiting system and method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wind power generation output limiting system and method for limiting the output of power generation with adjustable power generation and wind power generation in parallel with a grid.

[0002]

2. Description of the Related Art A generator that can adjust electric power such as an internal combustion power plant, a generator that operates at a constant output such as a geothermal power plant, and a system or a wind generator that can adjust electric power or a system including a wind generator In the system consisting of, the output is adjusted by the generator that can adjust the power to the output fluctuation of the wind power generator due to the fluctuation of the demand and the change of the wind speed, and the demand and supply of the power are adjusted.

However, since the output of wind power generation fluctuates due to changes in wind speed, when power is supplied to a small-scale grid,
Depending on the output fluctuation, it adversely affects the system frequency, voltage and other equipment. For example, when the power demand of the wind power generator increases with respect to the grid size, such as at night, when the power demand decreases, the output fluctuation of the wind power generator cannot be adjusted by the generator that can adjust the power, and the fluctuation of frequency, voltage, etc. Affect.

Therefore, in a situation where the output fluctuation of the wind power generator affects the quality of electricity, the wind turbine is stopped or the wind turbine is manually operated while checking the system frequency and the transmission end power of the entire system with an instrument. The maximum output is limited to suppress the output fluctuation of the wind power generator.

[0005]

When the number of generators operating in parallel to the system or the number of generators in operation changes with respect to the system load which changes every moment, the system frequency fluctuation capacity (frequency above the allowable frequency is exceeded). Electric power fluctuation that does not change)
Changes. In such an ever-changing grid load, the output fluctuation of the wind power generator is manually adjusted so that it falls within the grid frequency and grid voltage maintenance adjustment capability of the generator that can adjust the power in parallel. To do this, the operator must operate the instrument while constantly monitoring it, which imposes a heavy burden on the operator. Further, since the manual operation cannot be performed finely, there is a problem that the wind energy is often wasted by unnecessarily restricting the output of the wind power generator.

[0006]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned problems and to limit the output of wind power generation while maintaining the system frequency and voltage to effectively utilize wind energy.

To this end, the present invention is a wind power generation output limiting system for limiting the output of wind power generation in parallel with a system including power generation whose power can be adjusted. A limit value determining means for calculating and determining an output limit value of wind power generation, a generator in parallel with the system, and a limit value correcting means for monitoring the system frequency and correcting the output limit value, the limit value are provided. It is characterized in that the output limit value determined by the determining unit is corrected by the limit value correcting unit to limit the output of wind power generation.

The limit value determining means calculates an output fluctuation capacity in which the system frequency is in an allowable range with respect to the system capacity and an output of wind power generation with respect to the output fluctuation capacity, and is within an allowable output fluctuation amount from the system scale. Obtain the output of wind power generation, have a table that makes the relationship between the number of generators in parallel to the grid and the output of wind power generation within the output fluctuation amount, and from the number of generators in parallel to the grid and generator output The output limit value is determined based on the obtained system scale, the limit value correction means monitors the output of the generator in parallel with the system, corrects the output limit value so that it does not fall below the minimum output, and the system frequency. The output limit value is corrected so that the difference between the maximum value and the minimum value of the frequency within a certain time is within the set value, and the power factor of the generator in parallel with the system is monitored. Output control so that It is characterized in that to correct the values.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 is a diagram showing an embodiment of a wind power generation output limiting system according to the present invention, FIG. 2 is a diagram showing a configuration outline of a power system to which the wind power generation output limiting system according to the present invention is applied, and FIG. 3 is a diagram showing the present invention. It is a figure for explaining an example of the application state of the wind power generation output limiting system concerning this.
In the figure, 1 is an active power calculation unit, 2 is a reactive power calculation unit, 3 is a frequency fluctuation suppression control unit, 4 is a light load operation prevention control unit, 5
Is a frequency rise frequent occurrence suppression unit, 6 is a generator power factor adjustment value calculation unit, 7 is a maximum value determination unit, 8 is a calculation unit, 9 is a pulse setting unit, 10 is an output limit setting unit, and 11 is a wind turbine controller. .

In FIG. 1, an active power calculation unit 1 calculates a total value of active power of each generator except a wind power generator, and a reactive power calculation unit 2 calculates a reactive power of a power adjustable generator. The total value of is calculated. The frequency fluctuation suppression control unit 3 obtains a wind power output limit value corresponding to the total value of active power calculated by the active power calculation unit 1. For example, the allowable fluctuation amount within the system frequency ± 0.2 Hz is calculated for the system capacity, the wind condition data of the site is simulated, and the wind turbine output for the allowable variable capacity is calculated to be allowed from the system scale. The relation of the wind turbine output is made into a function so that it is within the output fluctuation amount. Then, the number of generators in parallel with the system and this function are made into a table, and the output limit value of wind power generation is determined from the number of generators in parallel with the system and the system scale obtained from the generators. As shown in Fig. 2, when the system is composed of a power adjustable power plant, a power plant that operates at a constant output, and a wind power plant, from the governor constant and the number of operating generators excluding the wind power plant, EMT power fluctuation allowance
A simulation is performed by using P to calculate the amount of power fluctuation in which the fluctuation of the system frequency in the number of operating generators and the system capacity is within the allowable value. Then, for example, the relationship of the wind turbine output with respect to the system scale as shown in FIG. 3 is derived. Three straight lines
I, II, and III are functions that switch depending on the number of generators in parallel in the system.

The light load operation prevention control unit 4 monitors the outputs of the generators capable of adjusting the electric power in parallel to the grid, and outputs the output correction values of the wind power generators that the output of those generators does not become below the minimum output. It is what you want. Frequency rise frequent occurrence suppression unit 5
Is to monitor the system frequency and obtain the output correction value of the wind power generator in which the difference between the maximum value and the minimum value of the frequency at an arbitrary time is within the set value. The generator power factor added / subtracted value calculation unit 6 detects the outputs of the generators capable of adjusting the electric power in parallel with the grid, and corrects the output of the wind power generators in which the power factor of those generators does not fall below a certain power factor. It seeks a value.

The maximum value determination unit 7 determines the maximum value among the respective correction values obtained by the light load operation prevention control unit 4, the frequency increase frequent occurrence suppression unit 5, and the generator power factor addition / subtraction value calculation unit 6. Yes, the calculation unit 8 corrects the wind power output limit value obtained by the frequency fluctuation suppression control unit 3 with the maximum value determined by the maximum value determination unit 7, and the pulse setter 9 with (wind power output limit value-maximum value).
Is operated to set an output limit value in the output limit setter 10. The wind turbine control device 11 controls the output of the wind power generator based on the output limit value set in the output limit setter 10.

In the wind power generation output limiting system according to the present invention, as shown in FIG. 2, for example, a power plant capable of adjusting electric power such as an internal combustion power plant or a hydro power plant, a power plant operating at a constant output such as a geothermal power plant, The electric power system is configured so that the load is supplied by a combination of wind power plants. Then, the total output P1 + P2 + P3 of each of these power plants is shown in FIG.
As shown in (A), the electric power demand P is adjusted and balanced. At this time, when the system scale is reduced by ΔP, in the conventional system, as shown in FIG.
The system is balanced by reducing it to ΔP. But,
In the present invention, when it is necessary to limit the output (wind turbine output) of wind power generation by determining the output limit value from the wind power generation output fluctuation and the system frequency fluctuation according to the number of generators operating in parallel and the output. In addition, as shown in FIG. 4 (C), the output of the wind power generation is P2-ΔP corresponding to the reduction of the system scale.
Or the power is output to the wind power generator and the system is balanced by reducing the power to ΔP.

In short, in the wind power generation output limiting system according to the present invention, the output fluctuation amount capable of maintaining the system frequency and the system voltage at the system scale is calculated from the governor constants and the number of generators constituting the system. Then, the wind condition data of the wind power plant is simulated, the amount of output fluctuation with respect to the wind turbine output is calculated, and the maximum value (output limit value) of the wind turbine output with respect to the system scale is calculated. Then, in order to eliminate the influence on other power generation equipment in parallel with the system, correction is added to the maximum output of the wind turbine from other generator states.

These control systems can be composed of, for example, an input / output unit for exchanging information such as a power adjustable generator in parallel with the grid and an output limit command to the wind turbine, a programmable controller and a monitoring meter. The maximum value of the wind turbine output (output limit value) is calculated by the programmable controller based on the information from the input / output unit, and the wind turbine output is limited through the input / output unit. In the programmable controller, the function of the wind turbine output related to the system scale obtained from the simulation is input by default, and a table is created in which the function can be selected according to the number of parallel generators with adjustable power. Then, the output limit value that is the maximum value that the wind turbine can output is calculated from the table and the function based on the parallel adjustable power generators, the total output of the constant output generators, and the number of units. The maximum value of the plurality of different correction values is corrected. They calculate the reactive power from the power factor of the power adjustable generators in parallel, and from the total and the total output of the power adjustable generators, the power factor of the whole power adjustable generators in parallel. When this power factor falls below the set power factor, the output limit decrease amount is calculated with a first-order delay according to the difference. Further, when the output of the generators with adjustable electric power in parallel decreases the lower limit output (set value), the output limit decrease amount is calculated with a first-order delay according to the decrease amount. Further, the system frequency is monitored, and when the difference between the maximum value and the minimum value for a certain period of time exceeds the set value, the output limit decrease amount is calculated with a first-order delay according to the amount.

FIG. 5 is a diagram for explaining a control flow for limiting the output of wind power generation, FIG. 6 is a diagram for explaining a flow for correcting the wind turbine output limit due to frequency fluctuation, and FIG. 7 is a flow for correcting a light load operation. FIG. 8 is a diagram for explaining, and FIG. 8 is a diagram for explaining a wind turbine output limit correction flow by maintaining the minimum power factor of the power adjustable generator.

The control flow in the wind power generation output limiting system according to the present invention determines, as shown in FIG. 5, that each of the power adjustable generators is operating at an output above a set value, and the system scale and output are determined. A function that meets the conditions is selected from the function table of the limit value (step S11). On the other hand, after obtaining the total output of the power adjustable generator (step S12), the total output of the generators other than the wind generator is combined with the output of the constant output generator (step S1).
3). Then, based on the function selected in step S11, the total generator output excluding the wind power generator calculated in step S13 is applied (step S14), and the wind turbine output limit value is calculated (step S15). On the other hand, the maximum value is obtained from the wind turbine output limit correction value due to frequency fluctuation, the light load operation prevention correction value, and the wind turbine output limit correction value due to maintaining the minimum power factor of the power adjustable generator (step S16), and step S15.
The wind turbine output limit value obtained in step S1 is corrected (step S1
7) Calculate the corrected wind turbine output limit value (step S1
8) Compare with the current wind turbine output limit value (step S1)
9). Then, according to the difference between the corrected wind turbine output limit value and the current wind turbine output limit value, an output limit value increase / decrease command for the wind turbine is generated (step S20) and output to the wind power station.

In the correction flow for obtaining the wind turbine output limit correction value due to the frequency fluctuation subject to the maximum value judgment in step S16, the busbar frequency fluctuation width during the set time is calculated (step S21) as shown in FIG. The value is compared with the fluctuation range setting value (step S22), and the wind turbine output limit correction value due to frequency fluctuation is obtained (step S23).

Further, in the correction flow for obtaining the light load operation prevention correction value, as shown in FIG. 7, the number of power adjustable generators in operation is multiplied by their rated outputs (step S31), and the operation is performed. The power adjustable power generator rated outputs during operation are totaled (step S32), and the minimum value of the power adjustable power generator rated output during operation is obtained using the set value (percentage) of the lowest power (step S33). The minimum value of the rated output of the adjustable power generator during operation is compared with the actual total output of the adjustable power generator obtained in step S12 (step S34) to obtain the light load operation prevention correction value ( Step S35).

In the correction flow for obtaining the wind turbine output limit correction value by maintaining the minimum power factor of the power adjustable generator, the reactive power is calculated from the output of each power adjustable generator and the power factor as shown in FIG. 8 (step S41). ), The total reactive power of the power adjustable generator is calculated (step S42). And
The total power factor of the power adjustable generator is calculated from the total power adjustable generator output and the total reactive power obtained in step S12 (step S43), and compared with the set value of the power factor limit value (step S44). ), A wind turbine output limit correction value by maintaining the minimum power factor of the power adjustable generator (step S
45).

The wind turbine output limitation correction will be further described. FIG. 9 is a diagram for explaining output limitation correction of a wind power generator for preventing light load operation, FIG. 10 is a diagram showing an example of first-order delay calculation, and FIG. 11 is a power factor lower limit value of a power adjustable generator. It is a figure for demonstrating the output limitation correction of a wind power generator.

Since the power adjustable generator cannot output less than 50%, in light load operation prevention, the wind load and the power adjustable generator provide the power balanced with the system load shown by the bold line in FIG. When generating electricity, the shaded portion of the vertical line limits the output of wind power generation. In this case, it is possible to know which unit is operating from the output of the generator whose power can be adjusted. Therefore, the output limit value of the wind power generator is the output limit value of the wind power generator = Power generation output of the entire system − (Constant output generator output + Minimum output of power adjustable generator) = (output of power adjustable generator + output of wind power generator) -minimum output of power adjustable generator where power generation output of entire system = power adjustable generator Output + Output of constant power generator + Output of wind power generator.

However, in the above equation, when the output fluctuation of the wind power generator is sudden, the output limit value changes due to the delay of the output follow-up of the power adjustable generator, and the operation below the minimum output is continued. If there is not, there is no particular problem. Therefore, regarding the output of the power adjustable generator, the value obtained by (minimum output-current output) x gain is calculated as the primary delay as shown in Fig. 10 to prevent light load operation. It is calculated as the output limit correction value of the wind power generator at.

The frequency of the grid is controlled by the governor of the power adjustable generator (output increase / decrease control), but the frequent increase in the frequency means that the wind conditions change drastically and the wind power generation The large output fluctuation is also considered as one of the factors. Therefore, in the frequency increase frequent occurrence suppression, (system frequency fluctuation value-frequency fluctuation set value) x gain where the frequency fluctuation value of the system = frequency-first-order lag is calculated for the value obtained by the reference frequency, and the frequency rise It is calculated as a wind turbine output limit correction value for frequent suppression.

When the power adjustable generator is represented by the phenomenon of the operating capacity curve as shown in FIG. 11, when the wind power generator increases the output while operating the power adjustable generator in the state of Adjustable generators reduce output to the'state. Therefore, the power factor of the power adjustable generator is worse than that of. Therefore, if the reactive power of the power adjustable generator increases, the output of the wind power generator is limited by entering the shaded portion of the vertical line. In this case, as in the case of preventing light load operation, the output limit value of the wind power generator is the output limit value of the wind power generator from the active power and the reactive power of the power adjustable generator. Power output + active power of minimum power factor) = (output of power adjustable generator + output of wind power generator) -active power of minimum power factor where power generation output of entire system = output of power adjustable generator + Output of constant output generator + Output of wind power generator If the minimum power factor is cos θ, the active power of the minimum power factor = reactive power · cos θ / sin θ can be obtained.

However, as in the case of preventing the light load operation, there is no particular problem unless the operation at the minimum power factor or less is continued, so that (minimum power factor-power factor of the entire power adjustable generator) × A first-order delay is calculated for the value obtained by the gain, and the value is calculated as the output limit correction value of the wind power generator at the power factor lower limit value of the power adjustable generator.

The wind power generation output limiting system according to the present invention adjusts the electric power by the function of the system scale and the wind generator output limiting value obtained from the total output of the generators excluding the wind generators connected in parallel to the grid as described above. The output of the wind power generator is automatically limited by creating a table according to the number and combination of parallel generators that are possible. Therefore, the output limit value is determined from the output fluctuation of the wind power generator and the system frequency fluctuation according to the number of generators operating in parallel and the output. First, as frequency fluctuation suppression, for example, an allowable output fluctuation amount within a frequency of ± 0.2 Hz is calculated with respect to the system capacity, the wind condition data of the area is simulated, and a wind turbine output corresponding to the allowable fluctuation capacity is calculated. , Limit the wind turbine output so that it is within the allowable output fluctuation amount from the system scale.

Then, in order to prevent light load operation of the system parallel generator, the output of the generator in parallel with the system is monitored and the output limit value is corrected so as not to fall below the minimum output. In addition, as a frequency increase frequent suppression, system frequency is monitored,
The output limit value is corrected so that the difference between the maximum value and the minimum value of the frequency within a certain time is within the set value. Further, to prevent the reduction of the power factor of the system parallel generator, the power factor of the generator in parallel with the system is monitored and the output limit value is corrected so as not to fall below a certain power factor.

In this way, the information of the generators in parallel in the power system is taken in and the output power (output limit value) of the wind power generation equipment is determined. The relationship between the amount of power fluctuation applied to the grid, the fluctuation cycle, and the frequency of the grid is made into a function or table based on the number of generators in operation and output, and the output limit value is determined by this. It has a function to monitor the output of the generator in parallel with the power system and correct the output limit value. It has a function to monitor the frequency of the grid and correct the output limit value. It has a function to monitor the power factor of the generator in parallel with the power system and correct the output limit value.

The present invention is not limited to the above embodiment, but various modifications can be made. For example, in the above-described embodiment, the internal combustion power plant and the geothermal power plant are described in parallel as a system configuration.However, a system in which a hydroelectric power plant, a wave power plant, a thermal power plant, and other power plants are parallel to the system. Needless to say, the same can be applied to.

[0031]

As is apparent from the above description, according to the present invention, there is provided a wind power generation output limiting system for limiting the output of wind power generation in parallel with a system including power generation whose power can be adjusted. Limit value determination means for determining the output limit value of wind power generation by calculating the number of generators operating in parallel and output, and a limiter for monitoring the generators in parallel with the grid and the grid frequency to correct the output limit value Value limiting means, and the output limiting value determined by the limiting value determining means is corrected by the limiting value correcting means to limit the output of the wind power generation.
The wind turbine output can be continuously limited while maintaining the voltage, and the wind energy can be effectively used.

Further, the limit value determining means calculates an output fluctuation capacity in which the system frequency is in an allowable range with respect to the system capacity and the output of the wind power generation with respect to the output fluctuation capacity, and within the allowable output fluctuation amount from the system scale. To obtain the output of
It has a table in which the relationship between the number of generators in parallel to the grid and the output of wind power generation that is within the output fluctuation amount is a function, and the output is limited based on the number of generators in parallel to the grid and the grid scale obtained from the generator output. The limit value correction means monitors the output of the generator in parallel with the grid, corrects the output limit value so that it does not fall below the minimum output, monitors the grid frequency, and monitors the maximum frequency in a certain period of time. Correct the output limit value so that the difference between the value and the minimum value is within the set value, monitor the power factor of the generator in parallel with the system, and correct the output limit value so that it does not fall below a certain power factor. Therefore, it is not necessary to monitor the wind turbine output, which changes every moment due to changes in the wind speed, and monitoring control can be performed at any time.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a wind power generation output limiting system according to the present invention.

FIG. 2 is a diagram showing a schematic configuration of a power system to which the wind power generation output limiting system according to the present invention is applied.

FIG. 3 is a diagram showing a configuration example of a table.

FIG. 4 is a diagram for explaining an example of an applied state of the wind power generation output limiting system according to the present invention.

FIG. 5 is a diagram for explaining a control flow for limiting the output of wind power generation.

FIG. 6 is a diagram for explaining a windmill output limit correction flow due to frequency fluctuation.

FIG. 7 is a diagram for explaining a light load operation prevention correction flow.

FIG. 8 is a diagram for explaining a wind turbine output limit correction flow by maintaining the minimum power factor of the power adjustable generator.

FIG. 9 is a diagram for explaining output limitation correction of a wind power generator in light load operation prevention.

FIG. 10 is a diagram showing an example of first-order delay calculation.

FIG. 11 is a diagram for explaining output limitation correction of the wind power generator at the power factor lower limit value of the power adjustable generator.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Active power calculation part, 2 ... Reactive power calculation part, 3 ... Frequency fluctuation suppression control part, 4 ... Light load operation prevention control part, 5 ... Frequency increase frequent suppression part, 6 ... Generator power factor adjustment value calculation part, 7 ...
Maximum value determination unit, 8 ... Calculation unit, 9 ... Pulse setting unit, 10 ...
Output limit setting unit, 11 ... Wind turbine control device

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 2001-178194 (JP, A) JP 2000-87841 (JP, A) JP 62-207200 (JP, A) JP 7-336901 ( JP, A) JP 2000-78896 (JP, A) JP 2001-37085 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H02P 9/00 F03D 7/04 F03D 9 / 00 H02J 3/46

Claims (7)

(57) [Claims] 1. A wind power generation output limiting system for limiting the output of wind power generation parallel to a grid including power generation with adjustable power, wherein wind power is calculated by calculating the number of generators operating in parallel and the output. A limit value determining means for determining an output limit value for power generation, a generator in parallel with the system, and a limit value correcting means for monitoring the system frequency to correct the output limit value are determined by the limit value determining means. A wind power generation output limiting system, wherein the output limit value is corrected by the limit value correcting means to limit the output of wind power generation. 2. The limit value determining means calculates an output fluctuation capacity in which a system frequency is within an allowable range with respect to a system capacity and an output of wind power generation with respect to the output fluctuation capacity, and within an allowable output fluctuation amount from a system scale. The wind power generation output limiting system according to claim 1, wherein the output limit value is determined by obtaining the output of the wind power generation. 3. The limit value deciding means has a table functioning the relationship between the number of generators in parallel with the grid and the output of wind power generation within the output fluctuation amount, and the number of generators in parallel with the grid. 3. The wind power generation output limiting system according to claim 2, wherein the output limiting value is determined based on a system scale obtained from the generator output. 4. The wind power generator according to claim 1, wherein the limit value correction means monitors the output of a generator in parallel with the grid and corrects the output limit value so that the output does not fall below a minimum output. Output limit system. 5. The limit value correcting means monitors the system frequency and corrects the output limit value so that the difference between the maximum value and the minimum value of the frequency within a certain time is within a set value. The wind power generation output limiting system according to claim 1. 6. The limit value correcting means monitors the power factor of a generator in parallel with the system, and corrects the output limit value so as not to fall below a certain power factor. Wind power output limiting system. 7. A wind power generation output limiting method for limiting output of wind power generation parallel to a grid including a generator capable of adjusting power, wherein the output is within an allowable range of grid frequency with respect to grid capacity. The variable capacity is calculated, the output of the wind power generation is calculated with respect to the output capacity, the output of the wind power generation is limited so that the output fluctuation amount is within the allowable output fluctuation amount from the grid size, and the grid frequency and power generation in parallel with the grid A wind power generation output limiting method comprising correcting the output limitation according to the output of the machine and the power factor.