JP2015173570A - Automatic frequency controller and automatic frequency control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce occurrence of an unnecessary supply and demand imbalance by performing control considering response delays of a plurality of power supply apparatuses.SOLUTION: An automatic frequency controller: periodically receives a measurement value measured in a power system and an output value showing output of each of a plurality of power supply apparatuses; calculates a supply and demand imbalance of the power system on the basis of the measurement value; calculates a corrected supply and demand imbalance by correcting the supply and demand imbalance on the basis of a stored instruction value and output values; calculates a distribution value for each of the plurality of power supply apparatuses by distributing the corrected supply and demand imbalance to the plurality of power supply apparatuses on the basis of a distribution ratio; calculates an instruction value by adding the distribution value to the output value for each of the plurality of power supply apparatuses; and transmits the calculated instruction value to each of the plurality of power supply apparatuses.

Description

  The present invention relates to a technique for controlling the frequency of a power system.

  In recent years, with the development of storage battery systems, the capacity has increased, and in the future, application to control of the entire power system is expected. Application to supply and demand control and voltage control that balance supply and demand is being studied. In particular, supply and demand control is expected to be applied to automatic frequency control (AFC) because of its responsiveness. On the other hand, compared with the conventional thermal power generator, there is a concern that the conventional control method is over-controlled because of its responsiveness, and the frequency is disturbed.

  As a conventional technique, Patent Document 1 discusses dividing an unbalanced part of a system into a plurality of frequency components by filtering, and sharing only a short-period component with a responsive generator.

JP 2007-306770 A

  According to the technique described in Patent Document 1, by sharing the short period component for the unbalance of the system to the storage battery, it becomes effective control regarding the speed of the output change speed. Since it is not possible to consider the responsiveness after reaching, hunting may occur.

  In order to solve the above problem, an automatic frequency control device according to one aspect of the present invention transmits a distribution ratio set to each of a plurality of power supply devices in an electric power system and each of the plurality of power supply devices. A storage unit for storing the command value, a measurement value measured in the power system, and an output value indicating each output of the plurality of power supply devices are periodically received, and based on the measurement value The power supply / demand imbalance of the power system is calculated, the corrected supply / demand imbalance is calculated by correcting the supply / demand imbalance based on the stored command value and the output value, and the correction is performed based on the distribution ratio. A distribution value of each of the plurality of power supply devices is calculated by allocating a supply / demand imbalance to the plurality of power supply devices, and a distribution value for each of the plurality of power supply devices is calculated. Calculating a command value by adding the distribution value to the output value, and a calculation unit that transmits the command value the calculated to each of the plurality of power supply devices.

  According to one embodiment of the present invention, unnecessary supply and demand imbalance can be reduced by controlling in consideration of response delays of a plurality of power supply apparatuses.

The function structure of the automatic frequency control apparatus of an Example is shown. An automatic frequency control process is shown. The 1st specific example of operation | movement of an automatic frequency control apparatus is shown. The 2nd specific example of operation | movement of an automatic frequency control apparatus is shown.

  Embodiments of the present invention will be described below with reference to the drawings.

  The automatic frequency control device receives the measured value in the target power system that is the power system to be controlled and the output value indicating the output of the generator in the target power system, and based on the measured value, By calculating a command value of the output of the generator and transmitting a command including the command value to the generator, the output of the generator is controlled and the frequency of the target power system is controlled. The automatic frequency control device is a part of the supply and demand control device in a central power supply command station of an electric power company, for example.

  In this embodiment, the power generator includes a power generator that performs only power generation by energy conversion, and a storage battery system that charges and discharges power. Such a generator and a storage battery system may be referred to as a power supply device that supplies power to the target power system. The storage battery system includes a storage battery and a storage battery control device such as a PCS (Power Conditioning Subsystem) or an energy management device. The generator or the storage battery control device is connected to the automatic frequency control device via the communication network, receives a command from the automatic frequency control device, and changes the output in accordance with the command.

  The response delay of the generator is a delay due to communication from when the automatic frequency control device transmits a command until it is received by the generator, and a delay from when the generator receives the command until the output reaches the command value. including. A generator having a rotor such as a thermal power generator has a long response time from receiving an instruction until the output reaches the instruction value, and has a large response delay. On the other hand, in the storage battery, the time from when the command is received until the output reaches the command value is shorter than that of the generator having the rotor, and the response speed is small.

  FIG. 1 shows a functional configuration of an automatic frequency control apparatus according to an embodiment.

  The automatic frequency control device is, for example, a computer, and includes a memory, a microprocessor such as a central processing unit (CPU), and a communication device. The memory stores programs and data for the automatic frequency controller. The microprocessor performs processing of the automatic frequency control device according to a program stored in the memory. The communication device performs communication according to instructions from the microprocessor. Note that the program of the automatic frequency control device may be stored in a computer-readable storage medium. In this case, the computer reads the program from the storage medium.

  The automatic frequency control device includes a system measurement data storage unit 100, a system setting data storage unit 101, a generator measurement data storage unit 102, a generator setting data storage unit 103, a command value storage unit 104, and system measurement data. A collection unit 200, a supply and demand imbalance calculation unit 201, a generator measurement data collection unit 202, a supply and demand imbalance correction unit 203, a command value calculation unit 204, and a command transmission unit 205 are included.

  The system setting data storage unit 101 stores system constants, reference frequencies, and interconnection schedules registered in advance by an administrator. The system constant indicates the relationship between frequency fluctuation and power fluctuation in the target power system, and depends on the size of the target power system and the magnitude of demand in the target power system. The reference frequency is a reference frequency of the target power system and may be referred to as a frequency setting value. The interconnecting line schedule is a planned value of interconnecting line flow at each time, and may be referred to as an interconnecting line flow setting value.

  The generator setting data storage unit 103 stores a distribution ratio and upper and lower limits registered in advance by the administrator for each generator. The distribution ratio indicates the magnitude of supply-demand imbalance allocated to the generator. The upper and lower limits include an upper limit value and a lower limit value indicating the range of the command value.

  The system measurement data collection unit 200 collects the frequency and interconnection power flow of the target power system from a server that manages information on the target power system, and the collected frequency and interconnection power flow are stored in the system measurement data storage unit. Save to 100. Here, the frequency is a measured value of the frequency in the target power system. The interconnected power flow is a measurement value of the interconnected power flow between the target power system and another power system. The server is provided in a central power supply command office or a sales office of an electric power company, and is connected to devices in the target power system and an automatic frequency control device via a communication network.

  The generator measurement data collection unit 202 collects output values from each generator, and stores the collected output values in the generator measurement data storage unit 102.

  The supply and demand imbalance calculation unit 201 includes the frequency and interconnection current flow stored in the system measurement data storage unit 100, the reference frequency, system constant, and interconnection line schedule stored in the system setting data storage unit 101. Based on the above, the supply and demand imbalance (area requirement: AR) is calculated.

  The supply and demand imbalance correction unit 203 is calculated by the supply and demand imbalance calculation unit 201 using the output value stored in the generator measurement data storage unit 102 and the command value stored in the command value storage unit 104. The corrected supply-demand imbalance is calculated by correcting the supply-demand imbalance.

  The command value calculation unit 204 uses the distribution ratio stored in the generator setting data storage unit 103 to distribute the corrected supply / demand imbalance calculated by the supply / demand imbalance correction unit 203 to each generator using the following formula. Thus, a distribution value indicating the distribution of the corrected supply and demand imbalance to each generator is calculated. Further, the command value calculation unit 204 calculates a command value for each generator based on the output value stored in the generator measurement data storage unit 102 and the calculated distribution value.

  The command value storage unit 104 stores the command value calculated by the command value calculation unit 204.

  Hereinafter, automatic frequency control processing by the automatic frequency control device will be described.

  FIG. 2 shows an automatic frequency control process.

  The automatic frequency control device periodically performs automatic frequency control processing. Here, each of the plurality of generators in the target power system is set as a distribution target generator.

  In S110, the supply and demand imbalance calculation unit 201 calculates the supply and demand imbalance by the following formula using the frequency, the interconnecting line flow, the reference frequency, the system constant, and the interconnecting line schedule.

Supply-demand imbalance =-system constant x (frequency-reference frequency)
+ (Connection line schedule-Connection line tide) (Formula 1)

  Here, the sign of the interconnection power flow is positive in the direction flowing into the target power system. That is, a positive interconnection current indicates that the demand in the target power system exceeds the supply from the generator in the target power system. Further, the positive direction of supply and demand imbalance indicates the direction in which supply is insufficient in the target power system. That is, when either the output of the generator in the target power system or the interconnecting power flow from another power system to the target power system is insufficient, the supply and demand imbalance changes in the positive direction. By this process, the supply and demand imbalance can be calculated from the measured values of the frequency of the target power system and the interconnection power flow.

  The supply / demand imbalance calculation unit 201 may smooth the supply / demand imbalance with a filter such as a first-order lag. The system measurement data collection unit 200 may collect power system demand from a power system server and store the collected demand in the system measurement data storage unit 100. In this case, the supply and demand imbalance may be calculated based on the demand and the interconnection current. Further, the system constant may be calculated based on the demand. In addition, the supply and demand imbalance calculation unit 201 does not use the second term of Equation 1 when it is not necessary to consider the interconnection between the target power system and another power system. In this case, the system measurement data collection unit 200 does not have to acquire the interconnection line flow, the system measurement data storage unit 100 does not have to store the interconnection line flow, and the system setting data storage unit 101 It is not necessary to memorize a connection line schedule. In this case, supply and demand imbalance can be calculated from the measured value of the frequency of the target power system.

  Here, the command value transmitted to the generator by the previous automatic frequency control process and stored in the command value storage unit 104 is referred to as a previous command value.

  In S120, the supply and demand imbalance correction unit 203 calculates the corrected supply and demand imbalance by correcting the supply and demand imbalance from the immediately preceding command value and the output value using the following equation.

  Correction value = Σ (previous command value−output value) (Expression 2)

  Corrected supply / demand imbalance = Supply / demand imbalance + Correction value (Equation 3)

  Here, the supply and demand imbalance correction unit 203 subtracts the output value from the immediately preceding command value of each distribution target generator, and calculates the total of the obtained values as a correction value. That is, the correction value indicates the influence of the response delay of the generator. Like the supply and demand imbalance, the positive direction of the correction value indicates a direction in which supply is insufficient in the target power system. By this process, it is possible to calculate a corrected supply and demand imbalance that takes into account the response delay of the generator.

  In S130, the command value calculation unit 204 calculates the distribution value indicating the distribution of the corrected supply / demand imbalance to the distribution target generator by allocating the corrected supply / demand imbalance to the plurality of distribution target generators by the following formula. .

  Distribution value = Corrected supply / demand imbalance × Distribution ratio / Total distribution ratio (Formula 4)

  In S <b> 140, the command value calculation unit 204 calculates a command value by the following formula from the output value and the distribution value for each distribution target generator.

  Command value = output value + distribution value (Formula 5)

  In S210, the command value calculation unit 204 determines whether or not the command value of the distribution target generator deviates from the range determined by the upper and lower limits.

  When it is determined in S210 that the command values of all the distribution target generators do not deviate from the range (N), the command value calculation unit 204 shifts the processing to S240.

  When it is determined in S210 that the command values of some of the distribution target generators are out of the range (Y), in S220, the command value calculation unit 204 selects the distribution target generator as the change target generator, and the change target Replace the generator command value with the upper or lower limit as follows:

  When the command value is larger than the upper limit value: Command value = upper limit value (Formula 6)

  When the command value is smaller than the lower limit value: Command value = lower limit value (Expression 7)

  By this process, the command value can be limited within a predetermined range. Note that the command value calculation unit 204 may change the command value of the change target generator to a value within the range.

  By this process, the distribution value of the change target generator changes, and the total distribution value of the distribution target generator does not match the corrected supply / demand imbalance. Therefore, the command value calculation unit 204 redistributes the corrected supply / demand imbalance. Here, the command value calculation unit 204 selects a generator other than the change target generator among the distribution target generators as the redistribution target generator. In S230, the command value calculation unit 204 recalculates the command value of the redistribution target generator by redistributing the corrected supply and demand imbalance as in the following equation, and shifts the processing to S210.

Total of distribution values of change target generators = Σ (command value of change target generator-output value of change target generator) (Equation 8)

Allocation value of generators to be redistributed = (corrected supply-demand imbalance-total allocation value of generators to be changed)
× Allocation ratio / Total allocation ratio of generators subject to reallocation (Formula 9)

  Command value = output value + distributed value (Equation 10)

  According to this process, even if the command value of the change target generator is changed, the corrected supply and demand imbalance can be redistributed to the distribution target generator, and the corrected supply and demand imbalance can be reflected in the command value.

  In S <b> 240, the command value calculation unit 204 stores the command value calculated for each generator in the command value storage unit 104. In S250, the command transmission unit 205 transmits a command including a command value to each generator, and ends this flow.

  The processes of S210 to S230 are repeated until the command values of all the distribution target generators reach the upper limit value or the lower limit value or the command values of all the distribution target generators are within the range.

  The above is the automatic frequency control process.

  According to this operation, it is possible to reflect the influence of the response delay of the generator on the command value by calculating the corrected supply and demand imbalance and allocating it to the command value.

  Hereinafter, a specific example of the operation of the automatic frequency control device will be described.

  FIG. 3 shows a first specific example of the operation of the automatic frequency control device.

  The distribution target generators in the first specific example are the thermal power generator A, the thermal power generator B, and the storage battery. This figure shows load, supply / demand imbalance, corrected supply / demand imbalance, output value and command value of thermal power generator A, output value and command value of thermal power generator B, and output value of storage battery for each time. And the command value. A load shows the sum total of the command value of all the generators.

  Here, the distribution ratio of the thermal power generator A, the thermal power generator B, and the storage battery is 1: 1: 2.

  The first specific example is an example when a step-like supply and demand imbalance occurs. The greater the corrected supply-demand imbalance, the greater the value of the battery command. Thereby, electric power supply can be made to follow quickly with respect to the sudden change of supply-demand imbalance. After the occurrence of the step-like supply / demand imbalance, the magnitude of the supply / demand imbalance immediately decreases and no hunting occurs, indicating that the automatic frequency control process does not overcontrol the generator.

  FIG. 4 shows a second specific example of the operation of the automatic frequency control device.

  The second specific example is an example in the case where supply and demand imbalance that fluctuates periodically occurs. As the absolute value of the corrected supply and demand imbalance increases, the command value of the storage battery changes particularly. Thereby, electric power supply can be made to follow quickly with respect to the periodic change of supply-demand imbalance. Since the supply and demand imbalance has not diverged, it can be seen that the automatic frequency control process does not overcontrol the generator.

  As shown in these specific examples, the influence of the response delay of the entire power system can be reduced by setting the distribution ratio higher for a generator with a smaller response delay. For example, by setting the distribution ratio of the storage battery higher than the distribution ratio of the generator such as thermal power, the response delay of the generator can be compensated by the storage battery.

  According to the present embodiment, in an automatic frequency control device that maintains a balance between supply and demand, it is possible to reduce the occurrence of unnecessary supply and demand imbalance by controlling in consideration of the response delay of the target generator. it can.

  Terms for the expression of the present invention will be described. The storage unit corresponds to the system measurement data storage unit 100, the system setting data storage unit 101, the generator measurement data storage unit 102, the generator setting data storage unit 103, the command value storage unit 104, and the like. The calculation unit includes a system measurement data collection unit 200, a supply and demand imbalance calculation unit 201, a generator measurement data collection unit 202, a supply and demand imbalance correction unit 203, a command value calculation unit 204, a command transmission unit 205, and the like. Correspond. The change target device corresponds to a change target generator or the like. The reallocation target device corresponds to a reallocation target generator or the like.

  The present invention is not limited to the above embodiments, and can be modified in various other forms without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 100 ... System | strain measurement data storage part 101 ... System | strain setting data storage part 102 ... Generator measurement data storage part 103 ... Generator setting data storage part 104 ... Command value storage part 200 ... System | strain measurement data collection part 201 ... Supply-and-demand imbalance calculation part 202 ... Generator measurement data collection unit 203 ... Supply / demand imbalance correction unit 204 ... Command value calculation unit 205 ... Command transmission unit

Claims (10)

A storage unit for storing a distribution ratio set for each of the plurality of power supply devices in the power system and a command value transmitted to each of the plurality of power supply devices;
The measurement value measured in the power system and the output value indicating the output of each of the plurality of power supply devices are periodically received, and the supply and demand imbalance of the power system is calculated based on the measurement value, A corrected supply-demand imbalance is calculated by correcting the supply-demand imbalance based on the stored command value and the output value, and the corrected supply-demand imbalance is distributed to the plurality of power supply devices based on the distribution ratio Calculating a distribution value of each of the plurality of power supply devices, calculating a command value by adding the distribution value to the output value for each of the plurality of power supply devices, and An arithmetic unit for transmitting the calculated command value to each of the devices;
An automatic frequency control device comprising: The plurality of power supply devices include a generator and a storage battery.
The automatic frequency control device according to claim 1. The measured value includes a frequency in the power system,
The calculation unit calculates the supply and demand imbalance based on a deviation of the frequency from a preset frequency setting value.
The automatic frequency control device according to claim 2. The calculation unit calculates the corrected supply and demand imbalance by adding a difference between the stored command value and the output value to the supply and demand imbalance.
The automatic frequency control device according to claim 3. The measured value includes a grid line flow between the power system and another power system,
The calculation unit calculates the supply and demand imbalance based on a deviation of the frequency from the frequency setting value and a deviation of the interconnection current from a preset interconnection current setting value.
The automatic frequency control device according to claim 4. The distribution ratio of the storage battery is higher than the distribution ratio of the generator,
The automatic frequency control apparatus according to claim 5. The storage unit stores a range of the command value for each of the plurality of power supply devices,
The arithmetic unit determines, for each of the plurality of power supply devices, whether or not the calculated command value deviates from the range, and sets the command value determined as deviating from the range. Selecting a corresponding power supply device as a change target device, and changing a command value of the change target device to a value within the range;
The automatic frequency control apparatus according to claim 6. When it is determined that the calculated command value is out of the range, the calculation unit performs redistribution supply / demand imbalance by subtracting the total distribution value of the change target device from the corrected supply / demand imbalance. Calculating, selecting a device other than the change target device from among the plurality of power supply devices as a redistribution target device, and allocating the redistribution supply / demand imbalance to the redistribution target device based on the distribution ratio. A redistribution value of the redistribution target device is calculated, and the command value is calculated by adding the redistribution value to the output value;
The automatic frequency control apparatus according to claim 7. When it is determined that the calculated command value exceeds the upper limit value of the range, the calculation unit changes the command value of the change target device to the upper limit value,
When it is determined that the calculated command value is below the lower limit value of the range, the calculation unit changes the command value of the change target device to the lower limit value.
The automatic frequency control apparatus according to claim 7 or 8. Store the distribution ratio set for each of the plurality of power supply devices in the power system,
Storing a command value transmitted to each of the plurality of power supply devices;
Periodically receiving the measured value measured in the power system and the output value indicating the output of each of the plurality of power supply devices;
Based on the measured value to calculate the supply and demand imbalance of the power system,
Calculating a corrected supply-demand imbalance by correcting the supply-demand imbalance based on the stored command value and the output value;
Calculating a distribution value of each of the plurality of power supply devices by allocating the corrected supply and demand imbalance to the plurality of power supply devices based on the distribution ratio;
A command value is calculated by adding the distribution value to the output value for each of the plurality of power supply devices,
Transmitting the calculated command value to each of the plurality of power supply devices;
An automatic frequency control method comprising:

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