Power grid frequency measurement apparatus and method

Abstract

A power grid frequency measurement apparatus and method, making the final obtained power grid frequency have both good real-time performance and high accuracy. The power grid frequency measurement apparatus (100) comprises: a synchronous motor (110), configured to be connected to a power grid and rotate under the drive of grid power; and a rotational speed measurement apparatus (120), configured to be connected to the synchronous motor (110) and output a target parameter on the basis of the rotational speed of the synchronous motor (110), wherein the target parameter indicates the power grid frequency.

Description

Apparatus and methods for measuring power grid frequency

[0001] This application claims priority to Chinese Patent Application No. 202410938790.1, filed on July 12, 2024, entitled "Apparatus and Method for Measuring Power Grid Frequency", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of power technology, and in particular to an apparatus and method for measuring power grid frequency. Background Technology

[0003] Grid frequency is a key parameter for grid operation and control. Grid frequency, typically 50 Hz or 60 Hz, refers to the frequency at which voltage and current change over time in an alternating current (AC) system. It is a direct indicator of the balance between power supply and demand in the power system. If power generation and consumption are mismatched, the grid frequency will change. By monitoring the grid frequency in real time, power generation, energy storage, and consumption can be adjusted promptly to prevent large disturbances to the grid, maintain a real-time balance between power supply and demand, ensure the grid frequency operates within permissible ranges, and guarantee the safe and stable operation of the grid.

[0004] Some emergency controls during sudden changes in grid frequency (e.g., control of inertial response of energy storage units, primary frequency regulation, etc.) require accurate and real-time grid frequency support. Therefore, how to accurately and in real-time measure the grid frequency is an urgent problem to be solved. Summary of the Invention

[0005] This application provides an apparatus and method for measuring power grid frequency, which enables the measured power grid frequency to not only have good real-time performance but also high accuracy.

[0006] In a first aspect, an apparatus for measuring power grid frequency is provided, comprising: a synchronous motor configured to be connected to a power grid and rotating under the power drive of the power grid; and a speed measuring device configured to be connected to the synchronous motor and outputting a target parameter based on the speed of the synchronous motor, the target parameter indicating the power grid frequency.

[0007] In this embodiment, a synchronous motor is configured to be connected to the power grid and rotate under the power drive of the grid. Thus, the rotational speed of the synchronous motor reflects the grid frequency. Since the synchronous motor is synchronized with the grid at all times, its rotational speed can reflect the grid frequency in real time with almost no time lag, resulting in a fast response speed when used for grid control. Furthermore, by configuring a speed measuring device to be connected to the synchronous motor and outputting target parameters based on the motor's rotational speed, the rotational speed of the synchronous motor can be measured efficiently and accurately, resulting in a grid frequency that is not only real-time but also highly accurate.

[0008] In some possible implementations, the rotational speed measuring device includes a rotating optical device coaxially connected to the synchronous motor, and the target parameter includes the period or frequency of the output signal of the rotating optical device.

[0009] The above technical solution configures the speed measuring device as a rotating optical device coaxially connected to the synchronous motor. On the one hand, the rotating optical device rotates synchronously with the synchronous motor, allowing the output signal of the rotating optical device to accurately reflect the speed of the synchronous motor, and thus the power grid frequency. On the other hand, the frequency of the output signal of the rotating optical device is much higher than the power grid frequency and is relatively easy to measure, effectively reducing the computational complexity of determining the power grid frequency.

[0010] In some possible implementations, the rotary optical device includes a rotary photoelectric encoder, and the output signal includes a pulse signal.

[0011] This technical solution sets the speed measuring device as a rotary photoelectric encoder. The pulse signal output by the rotary photoelectric encoder can reflect the current power grid frequency in real time, thereby improving the timeliness of the determined power grid frequency.

[0012] In some possible implementations, the power grid frequency f satisfies the following formula:

[0013] Wherein, T1 is the period of the pulse signal, k1 and k2 are constants, k1 is determined based on the synchronous motor, k2 is determined based on the rotary photoelectric encoder, and k2 is greater than or equal to 300.

[0014] A larger k2 results in higher resolution for the power grid frequency measurement device, but also increases the cost of the rotary photoelectric encoder. The above technical solution, when the speed measurement device includes a rotary photoelectric encoder, sets k2 to be greater than or equal to 300. This comprehensively considers both the resolution and cost of the power grid frequency measurement device, effectively improving the resolution of the device at a lower cost, thereby enhancing the accuracy of the power grid frequency measurement.

[0015] In some possible implementations, the speed measuring device includes a DC motor coaxially connected to the synchronous motor, and the target parameter includes a voltage signal output by the DC motor.

[0016] The above technical solution sets the speed measuring device to include a DC motor coaxially connected to the synchronous motor. On the one hand, the DC motor rotates synchronously with the synchronous motor, so that the amplitude of the voltage signal output by the DC motor can accurately reflect the speed of the synchronous motor, and thus reflect the grid frequency. On the other hand, the technology for measuring voltage signals is relatively mature and simple, effectively reducing the complexity of determining the grid frequency.

[0017] In some possible implementations, the power grid frequency f satisfies the following formula:

[0018] Wherein, U is the amplitude of the voltage signal, k1 and k3 are constants, k1 is determined based on the synchronous motor, and k3 is determined based on the DC motor.

[0019] In some possible implementations, k1 is greater than or equal to 1.

[0020] This technical solution sets k1 to be greater than or equal to 1, which can ensure the resolution of the power grid frequency measurement device, thereby making the target parameters more accurate and the final power grid frequency more accurate.

[0021] In some possible implementations, a voltage conversion device is also included, wherein the high-voltage end of the voltage conversion device is connected to the bus of the power grid, and the low-voltage end of the voltage conversion device is connected to the synchronous motor, so that the synchronous motor rotates under the drive of the low-voltage end.

[0022] The above technical solution connects the voltage conversion device between the power grid and the synchronous motor. The synchronous motor may be a miniature synchronous motor. The voltage conversion device converts the high voltage on the bus to a low voltage and inputs it to the synchronous motor to meet the input requirements of the miniature synchronous motor.

[0023] In some possible implementations, the voltage conversion device includes a current transformer.

[0024] Since instrument transformers are commonly used devices in power systems to convert high voltage to low voltage, the above technical solution includes an instrument transformer in the voltage conversion device, which facilitates the measurement of power grid frequency.

[0025] In some possible implementations, the speed measuring device is configured to output a series of target parameters based on the speed of the synchronous motor, the average value of the series of target parameters being used to indicate the grid frequency.

[0026] The above technical solution uses the average value of multiple consecutive target parameters to determine the power grid frequency, which reduces the interference of jitter in power grid frequency measurement and thus effectively improves the accuracy of the determined power grid frequency.

[0027] In a second aspect, a method for measuring power grid frequency is provided, comprising: supplying power to a synchronous motor via a power grid to cause the synchronous motor to rotate under the power drive of the power grid; acquiring a target parameter by means of a speed measuring device connected to the synchronous motor, the target parameter indicating the power grid frequency; and determining the power grid frequency based on the target parameter.

[0028] In some possible implementations, the speed measuring device includes a rotating optical device, and the acquisition of the target parameter through the speed measuring device connected to the synchronous motor includes: acquiring the period or frequency of the output signal of the rotating optical device through the rotating optical device coaxially connected to the synchronous motor; the determination of the power grid frequency based on the target parameter includes: determining the power grid frequency based on the period or frequency of the output signal.

[0029] In some possible implementations, the rotary optical device includes a rotary photoelectric encoder, and the output signal includes a pulse signal output by the photoelectric encoder.

[0030] In some possible implementations, the power grid frequency f satisfies the following formula:

[0031] Wherein, T1 is the period of the pulse signal, k1 and k2 are constants, k1 is determined based on the synchronous motor, k2 is determined based on the rotary photoelectric encoder, and k2 is greater than or equal to 300.

[0032] In some possible implementations, the speed measuring device includes a DC motor, and the acquisition of the target parameter via the speed measuring device connected to the synchronous motor includes: acquiring the voltage signal output by the DC motor via the DC motor coaxially connected to the synchronous motor; the determination of the grid frequency based on the target parameter includes: determining the grid frequency based on the voltage signal.

[0033] In some possible implementations, the power grid frequency f satisfies the following formula:

[0034] Wherein, U is the amplitude of the voltage signal, k1 and k3 are constants, k1 is determined based on the synchronous motor, and k3 is determined based on the DC motor.

[0035] In some possible implementations, k1 is greater than or equal to 1.

[0036] In some possible implementations, the method further includes: controlling the high-voltage end of the voltage conversion device to draw power from the AC bus of the power grid; controlling the voltage conversion device to transfer the power drawn from the AC bus to the low-voltage end of the voltage conversion device; the power supply to the synchronous motor through the power grid includes: using the low-voltage end to supply power to the synchronous motor.

[0037] In some possible implementations, the voltage conversion device includes a current transformer.

[0038] In some possible implementations, acquiring the target parameters via a speed measuring device connected to the synchronous motor includes: acquiring a plurality of consecutive target parameters via the speed measuring device; determining the grid frequency based on the target parameters includes: determining the grid frequency based on the average value of the plurality of consecutive target parameters.

[0039] In some possible implementations, the method further includes: controlling the energy storage device to discharge when the current grid frequency is lower than the previous grid frequency; and controlling the energy storage device to charge when the current grid frequency is higher than the previous grid frequency.

[0040] Thirdly, an apparatus for measuring power grid frequency is provided, comprising: a power supply unit for supplying power to a synchronous motor via a power grid, so that the synchronous motor rotates under the power drive of the power grid; a processing unit for acquiring a target parameter through a speed measuring device connected to the synchronous motor, the target parameter indicating the power grid frequency; the processing unit is further configured to determine the power grid frequency based on the target parameter.

[0041] Fourthly, an apparatus for measuring power grid frequency is provided, comprising a processor and a memory, wherein the memory is used to store a computer program, and the processor is used to invoke the computer program to execute the methods in the second aspect or its various implementations described above.

[0042] Fifthly, a computer-readable storage medium is provided for storing a computer program that causes a computer to perform the methods described in the second aspect or its implementations. Attached Figure Description

[0043] Figure 1 shows a schematic diagram of a power grid frequency measurement device according to an embodiment of this application.

[0044] Figure 2 shows a schematic diagram of another power grid frequency measurement device according to an embodiment of this application.

[0045] Figure 3 shows a schematic flowchart of a method for measuring power grid frequency according to an embodiment of this application.

[0046] Figure 4 shows a schematic block diagram of a power grid frequency measurement device according to an embodiment of this application.

[0047] Figure 5 shows a schematic block diagram of a power grid frequency measurement device according to an embodiment of this application. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0049] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the specification of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, rather than to describe a specific order or hierarchy.

[0050] The directional terms used in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of this application. It should also be noted in the description of this application that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0051] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0052] In this application, "multiple" refers to two or more (including two), and similarly, "multiple groups" refers to two or more (including two), and "multiple pieces" refers to two or more (including two).

[0053] Measuring the power grid frequency is crucial for ensuring the stable and efficient operation of the power grid, and it is essential for the operation of the power system. The reasons for measuring the power grid frequency mainly include the following aspects:

[0054] (1) The grid frequency is a direct indicator of the system's supply and demand balance. If the power generation and consumption are mismatched, the grid frequency will change. By monitoring the frequency in real time, the power generation can be adjusted in a timely manner to maintain the supply and demand balance, prevent the grid frequency from deviating from the normal operating range, and thus ensure the stability of the grid.

[0055] (2) Generator sets, transformers and other power equipment are designed to operate within a specific frequency range. Too high or too low a frequency may cause damage to the equipment. Accurate frequency measurement helps to take timely measures to protect the equipment from damage when the frequency is abnormal.

[0056] (3) Frequency fluctuations can affect power quality. Many electrical devices have strict requirements for power quality. Frequency fluctuations may affect their performance and lifespan. Frequency measurement helps ensure the provision of high-quality power.

[0057] (4) Grid operators need to adjust power generation resources according to load forecasts. Frequency measurement helps to optimize generator operation, achieve economic dispatch, and reduce power generation costs.

[0058] (5) In an open electricity market, real-time grid frequency data is an important reference for electricity trading. Accurate frequency measurement contributes to the efficient operation of the electricity market.

[0059] (6) Many countries and regions have regulations requiring the power industry to monitor and report grid frequencies to ensure compliance with industry standards and regulations.

[0060] Therefore, measuring power grid frequency is crucial for ensuring the safe, stable, and economical operation of the power grid. Accurate measurement and monitoring can promptly identify and address potential problems, ensuring the healthy operation of the power system.

[0061] In some cases, grid control (e.g., controlling the inertial response of energy storage units, primary frequency regulation, etc.) requires accurate and real-time grid frequency support. Currently, most methods for measuring grid frequency are software-based. Specifically, these methods involve collecting sufficient grid voltage data and analyzing it to obtain the grid frequency. However, collecting voltage data typically requires at least one voltage data cycle, for example, 20ms. This results in a time lag in the obtained grid frequency, such as 20ms, which cannot adequately meet the rapid response requirements of energy storage units.

[0062] Based on this, embodiments of this application provide a device for measuring power grid frequency, which includes a synchronous motor and a speed measuring device. The synchronous motor is configured to be connected to the power grid and rotate under the power of the grid; the speed measuring device is configured to be connected to the synchronous motor and outputs a target parameter based on the synchronous motor's speed, the target parameter indicating the power grid frequency. By configuring the synchronous motor to be connected and rotate under the power of the grid, the synchronous motor's speed can reflect the power grid frequency. Since the synchronous motor is synchronized with the power grid at all times, its speed can reflect the power grid frequency in real time with almost no time lag, resulting in a fast response speed when used for power grid control. Furthermore, configuring the speed measuring device to be connected to the synchronous motor and outputting a target parameter based on the synchronous motor's speed facilitates efficient and accurate measurement of the synchronous motor's speed, resulting in a final power grid frequency that is not only real-time but also highly accurate.

[0063] Figure 1 shows a schematic diagram of a power grid frequency measurement device 100 according to an embodiment of this application. As shown in Figure 1, the power grid frequency measurement device 100 includes a synchronous motor 110 and a speed measuring device 120. The synchronous motor 110 is configured to be connected to the power grid and rotates under the power drive of the power grid. The speed measuring device 120 is configured to be connected to the synchronous motor 110 and outputs a target parameter based on the speed of the synchronous motor 110, the target parameter indicating the power grid frequency.

[0064] In this embodiment, the synchronous motor 110 is configured to be connected to the power grid and rotate under the power drive of the grid. Thus, the rotational speed of the synchronous motor 110 reflects the grid frequency. Since the synchronous motor 110 is synchronized with the grid at all times, its rotational speed can reflect the grid frequency in real time with almost no time lag, resulting in a fast response speed when used for grid control. Furthermore, the speed measuring device 120 is configured to be connected to the synchronous motor 110 and outputs target parameters based on the rotational speed of the synchronous motor 110, facilitating efficient and accurate measurement of the synchronous motor 110's rotational speed. This results in a final grid frequency that is not only real-time but also highly accurate.

[0065] The synchronous motor 110 can be relatively small in size, meaning it can be a miniature synchronous motor. Alternatively, the synchronous motor 110 can be a permanent magnet synchronous motor, a reluctance synchronous motor, a brushless synchronous motor, etc.

[0066] The speed of synchronous motor 110 is proportional to the grid frequency, that is, the speed of synchronous motor 110 and the grid frequency satisfy the following formula: v=k1f (1)

[0067] Where f is the grid frequency, v is the synchronous motor speed, and k1 is a constant.

[0068] k1 indicates the speed of the synchronous motor. In other words, k1 is related to the synchronous motor; once synchronous motor 110 is selected, k1 has a definite value. Therefore, k1 can be understood as one of the attributes of the synchronous motor, and normally, k1 = 1.

[0069] k1 can be determined by the rotational speed of the synchronous motor 110. For example, if the rotational speed of the synchronous motor 110 is 3000 revolutions per minute at the rated frequency (50Hz), then k1 = 1. As another example, if the rotational speed of the synchronous motor 110 is 4500 revolutions per minute at the rated frequency, since k1 = 1 corresponds to a rotational speed of 3000 revolutions per minute, and the synchronous motor 110's rotational speed is 4500 revolutions per minute, then k1 = 1.5. Similarly, if the rotational speed of the synchronous motor 110 is 6000 revolutions per minute at the rated frequency, then k1 = 2.

[0070] To ensure the resolution of the power grid frequency measurement device, the synchronous motor 110 cannot rotate too slowly. If the synchronous motor 110 rotates too slowly, in some cases, even if the power grid frequency changes by a large value, the target parameter output by the speed measurement device 120 may not change. Therefore, in this embodiment, k1 needs to be sufficiently large.

[0071] Optionally, k1 can be greater than or equal to 1. For example, k1 can be greater than or equal to 1.5, or k1 can be greater than or equal to 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, etc.

[0072] This technical solution sets k1 to be greater than or equal to 1, which can ensure the resolution of the power grid frequency measurement device, thereby making the target parameters more accurate and the final power grid frequency more accurate.

[0073] In one embodiment, the rotational speed measuring device 120 may include a rotating optical device that can be coaxially connected to the synchronous motor 110, in which case the target parameter includes the period or frequency of the output signal of the rotating optical device.

[0074] This technical solution configures the speed measuring device 120 to include a rotating optical device coaxially connected to the synchronous motor 110. On one hand, the rotating optical device rotates synchronously with the synchronous motor 110, allowing the output signal of the rotating optical device to accurately reflect the speed of the synchronous motor 110, and thus the power grid frequency. On the other hand, the frequency of the output signal of the rotating optical device is much higher than the power grid frequency and is relatively easy to measure, effectively reducing the complexity of determining the power grid frequency.

[0075] As an example, a rotating optical device may include a light source that rotates along with a synchronous motor 110. Each rotation of the synchronous motor 110 sweeps across a light-sensing area of ​​the light source, and the count can be incremented by one. Thus, the rotational speed of the synchronous motor 110 can be obtained, for example, how many revolutions the synchronous motor 110 makes per second, and the grid frequency can then be obtained according to formula (1).

[0076] As another example, a rotary optical device may include a rotary photoelectric encoder. In this case, the output signal may include a pulse signal.

[0077] Because rotary photoelectric encoders have low inertia, they can respond quickly to changes in the power grid frequency. Therefore, this technical solution uses a rotary photoelectric encoder as the speed measuring device 120, and the output pulse signal can reflect the current power grid frequency in real time, thereby improving the accuracy of the determined power grid frequency.

[0078] The shaft of synchronous motor 110 drives a rotary photoelectric encoder. The frequency of the pulse signal output by the rotary photoelectric encoder is proportional to the rotational speed of the shaft of synchronous motor 110. That is, the frequency of the pulse signal and the rotational speed of synchronous motor 110 satisfy the following formula: f1=k2v (2)

[0079] Where f1 is the frequency of the pulse signal and k2 is a constant.

[0080] k2 is related to the rotary photoelectric encoder. Once the rotary photoelectric encoder is selected, k2 has a definite value. k2 indicates the number of pulses output by the rotary photoelectric encoder when the synchronous motor rotates one revolution. After determining the rotary photoelectric encoder, k2 can be determined by the number of pulses output by the rotary photoelectric encoder when the synchronous motor 110 rotates one revolution.

[0081] According to formulas (1) and (2), the power grid frequency can be obtained as follows:

[0082] Where T1 is the period of the pulse signal, T1 = 1 / f1.

[0083] Therefore, by measuring the period T1 or frequency f1f1 of the pulse signal output by the rotary photoelectric encoder, the real-time measurement of the power grid frequency can be achieved.

[0084] Considering that the more pulses the rotary encoder outputs for one revolution of the synchronous motor 110, the higher the resolution for the power grid frequency, similar to k1, k2 needs to be sufficiently large to ensure the resolution of the power grid frequency measurement device. However, considering that a larger k2 results in a more expensive rotary photoelectric encoder, and taking into account both the resolution and cost of the power grid frequency measurement device, k2 can optionally be greater than or equal to 100, or even larger than or equal to 300.

[0085] For example, k2 can be greater than or equal to 400, 500, 600, 700, 800, 900, 1000, 1200, 1400, 1600, etc.

[0086] It should be understood that a rotary photoelectric encoder is a sensor that uses the photoelectric effect to detect rotation angle. It consists of a light source, an encoder disk, and a detector. The encoder disk has a series of alternating light-transmitting and light-blocking lines or holes. When the encoder disk rotates with the shaft, light shines through the light-transmitting parts onto the detector, while the light is blocked in the light-blocking parts. Thus, as the encoder disk rotates, the detector receives a series of pulse signals. One revolution of the synchronous motor 110 corresponds to one revolution of the rotary photoelectric encoder. If k2 equals 300, it means that 300 pulse signals are emitted during one revolution of the rotary photoelectric encoder.

[0087] The above technical solution, in the case that the speed measuring device 120 includes a rotary photoelectric encoder, sets k2 to be greater than or equal to 300, taking into account the resolution and cost of the power grid frequency measuring device, and effectively improves the resolution of the power grid frequency measuring device 100 at a lower cost, thereby improving the accuracy of the power grid frequency.

[0088] In another embodiment, the speed measuring device 120 may include a DC motor, which is coaxially connected to the synchronous motor 110. In this case, the target parameter may include the voltage signal output by the DC motor, i.e., the voltage signal output by the DC motor can reflect the power grid frequency.

[0089] The above technical solution configures the speed measuring device 120 to include a DC motor coaxially connected to the synchronous motor 110. On the one hand, the DC motor rotates synchronously with the synchronous motor 110, so that the amplitude of the voltage signal output by the DC motor can accurately reflect the speed of the synchronous motor 110, and thus reflect the power grid frequency. On the other hand, the technology for measuring voltage signals is relatively mature and simple, effectively reducing the complexity of determining the power grid frequency.

[0090] In this case, the grid frequency f can satisfy the following formula:

[0091] Where U is the amplitude of the voltage signal, and k3 is a constant.

[0092] k3 is determined based on the DC motor; that is, k3 is related to the DC motor, and once the DC motor is selected, k3 has a definite value. k3 can represent the sensitivity of the DC motor's output voltage signal to the power grid frequency. For example, k3 can be the slope of a straight line formed by the power grid frequency and the amplitude of the voltage signal.

[0093] Theoretically, the higher the power grid frequency, the greater the amplitude of the voltage signal. However, considering the measurement range and resolution of the power grid frequency, the amplitude of the voltage signal cannot increase indefinitely as the power grid frequency continues to increase. Therefore, the amplitude U of the voltage signal needs to meet certain requirements. Optionally, the value of U can be between 0 volts (V) and 10V. For example, the value of U can be between 0V and 8V, or between 0V and 5V, or between 2V and 9V, or between 3V and 7V, etc.

[0094] In some embodiments, the synchronous motor 110 can be directly connected to the power grid. For example, the synchronous motor 110 can be directly connected to the low-voltage point of the AC bus of the power grid.

[0095] Considering that the power grid may be as high as thousands of volts, and that the synchronous motor 110 is an instrument, if the synchronous motor 110 is directly connected to the power grid, safety accidents or other adverse effects may occur.

[0096] Therefore, in some other embodiments, as shown in FIG2, the power grid frequency measurement device 100 may further include a voltage conversion device 130, the high voltage end of the voltage conversion device 130 being connected to the AC bus of the power grid, and the low voltage end of the voltage conversion device 130 being connected to the synchronous motor 110, so that the synchronous motor 110 rotates under the drive of the low voltage end.

[0097] In other words, the voltage conversion device can output a secondary voltage value based on the primary voltage value of the AC bus, and the synchronous motor is configured to rotate under the drive of the secondary voltage value. That is, the voltage conversion device 130 is connected to the power grid through the AC bus and supplies power to the synchronous motor 110. The voltage conversion device 130 can convert high voltage to low voltage.

[0098] For example, the primary voltage value can be greater than or equal to 500V, for example, greater than 1000V, and the secondary voltage value can be in the range of 100V-200V.

[0099] The above technical solution connects the voltage conversion device 130 between the power grid and the synchronous motor 110. Since the synchronous motor 110 may be a miniature synchronous motor, it can adapt to the input requirements of the miniature synchronous motor, thereby reducing the possibility of damage to the synchronous motor 110 or even causing a safety accident due to the direct input of high voltage from the AC bus to the synchronous motor, and ensuring the normal operation of the power grid frequency measurement device 100.

[0100] Optionally, the number of voltage conversion devices 130 can be one.

[0101] Optionally, there can be multiple voltage conversion devices 130. In this case, the synchronous motor 110 can rotate using at least a portion of the multiple secondary voltage values ​​output by the multiple voltage conversion devices 130. For example, the synchronous motor 110 can rotate using the maximum value among the multiple secondary voltage values, or it can rotate using the minimum value among the multiple secondary voltage values, or it can rotate using the average value among the multiple secondary voltage values.

[0102] Optionally, the voltage conversion device 130 may include a current transformer. For example, the voltage conversion device 130 may be a voltage transformer or a current transformer.

[0103] Since instrument transformers are commonly used devices in power systems to convert high voltage to low voltage, the above technical solution sets the voltage conversion device 130 to include an instrument transformer, which facilitates the measurement of power grid frequency.

[0104] In other embodiments, the synchronous motor 110 may be connected to another power source operating at the same frequency as the power grid. Alternatively, the synchronous motor 110 may be directly connected to another power source, or the synchronous motor 110 may be connected to another power source via a voltage conversion device 130.

[0105] In some other embodiments, the synchronous motor 110 can be connected to other devices in the power grid, such as fire-fighting equipment. In other words, the synchronous motor 110 can draw power from other parts of the power grid.

[0106] Optionally, in this embodiment of the application, the rotational speed measuring device 120 may output a target parameter.

[0107] Alternatively, the speed measuring device 120 can output multiple target parameters, at least some of which can be used to indicate the power grid frequency. For example, in the case where the speed measuring device 120 is a rotary photoelectric encoder, the rotary photoelectric encoder can output multiple pulse signals per second, at least some of which are used to indicate the power grid frequency.

[0108] For example, one of the multiple target parameters can be used to indicate the grid frequency. For instance, the maximum value among the multiple target parameters can be used to indicate the grid frequency, or the minimum value among the multiple target parameters can be used to indicate the grid frequency, or any one of the multiple target parameters can be used to indicate the grid frequency, or the median value among the multiple target parameters can be used to indicate the grid frequency.

[0109] As another example, in order to reduce jitter interference in grid frequency measurements, at least two of the plurality of target parameters can be used to indicate the grid frequency.

[0110] For example, all target parameters can be used to indicate the grid frequency, such as the average value of all target parameters indicating the grid frequency.

[0111] At this point, f1 satisfies the following formula:

[0112] Among them, f 1i f1 is a sequence of measurements, i.e., multiple target parameters, i = 1, 2, 3, ..., N.

[0113] Combining formula (3), we can obtain:

[0114] The above technical solution uses the average value of multiple target parameters to determine the power grid frequency, which reduces the interference of jitter in power grid frequency measurement and thus effectively improves the accuracy of the determined power grid frequency.

[0115] Alternatively, other target parameters besides the maximum and minimum values ​​can be used to indicate the grid frequency. Or, any two of the target parameters can indicate the grid frequency.

[0116] It should be noted that the multiple target parameters mentioned above can represent a series of consecutive target parameters. For example, the power grid frequency can be determined based on the average of frequency measurements determined by multiple target parameters.

[0117] After obtaining the grid frequency, the grid frequency can be used to perform some operations.

[0118] For example, if the current grid frequency is lower than the previous grid frequency (i.e., the grid frequency has decreased), it indicates that the grid's power generation is less than its power consumption. In this case, the grid can control the energy storage device to discharge, thereby increasing the grid frequency. Conversely, if the current grid frequency is higher than the previous grid frequency (i.e., the grid frequency has increased), it indicates that the grid's power generation is greater than its power consumption. In this case, the grid can control the energy storage device to charge, thereby decreasing the grid frequency and maintaining the grid in a stable state.

[0119] The embodiments of the power grid frequency measurement apparatus of this application have been described in detail above with reference to Figures 1 and 2. The method embodiments of this application are described below with reference to Figure 3. It should be understood that the method embodiments correspond to the apparatus embodiments, and similar descriptions can be made with reference to the apparatus embodiments.

[0120] Figure 3 shows a schematic flowchart of a method for measuring power grid frequency according to an embodiment of this application. As shown in Figure 3, the method 300 for measuring power grid frequency may include the following steps.

[0121] S310: The synchronous motor is powered by the power grid so that it rotates under the power of the power grid.

[0122] S320: The target parameter is obtained through a speed measuring device connected to the synchronous motor. The target parameter indicates the power grid frequency.

[0123] S330: Determine the power grid frequency based on the target parameters.

[0124] Optionally, in some embodiments, method 300 further includes: controlling the energy storage device to discharge when the current grid frequency is lower than the previous grid frequency; and controlling the energy storage device to charge when the current grid frequency is higher than the previous grid frequency.

[0125] Optionally, in some embodiments, the speed measuring device includes a rotating optical device, and the step of obtaining the target parameter through the speed measuring device connected to the synchronous motor includes: obtaining the period or frequency of the output signal of the rotating optical device through the rotating optical device coaxially connected to the synchronous motor; the step of determining the power grid frequency according to the target parameter includes: determining the power grid frequency according to the period or frequency of the output signal.

[0126] Optionally, in some embodiments, the rotary optical device includes a rotary photoelectric encoder, and the output signal includes a pulse signal output by the photoelectric encoder.

[0127] Optionally, in some embodiments, the power grid frequency f satisfies the following formula:

[0128] Wherein, T1 is the period of the pulse signal, k1 and k2 are constants, k1 is determined based on the synchronous motor, k2 is determined based on the rotary photoelectric encoder, and k2 is greater than or equal to 300.

[0129] Optionally, in some embodiments, the speed measuring device includes a DC motor, and the step of obtaining the target parameter through the speed measuring device connected to the synchronous motor includes: obtaining the voltage signal output by the DC motor through the DC motor coaxially connected to the synchronous motor; the step of determining the grid frequency based on the target parameter includes: determining the grid frequency based on the voltage signal.

[0130] Optionally, in some embodiments, the power grid frequency f satisfies the following formula:

[0131] Wherein, U is the amplitude of the voltage signal, k1 and k3 are constants, k1 is determined based on the synchronous motor, and k3 is determined based on the DC motor.

[0132] Optionally, in some embodiments, k1 is greater than or equal to 1.

[0133] Optionally, in some embodiments, method 300 further includes: controlling the high-voltage end of the voltage conversion device to draw power from the AC bus of the power grid; controlling the voltage conversion device to transfer the power drawn from the AC bus to the low-voltage end of the voltage conversion device; the step of supplying power to the synchronous motor through the power grid includes: supplying power to the synchronous motor using the low-voltage end.

[0134] Optionally, in some embodiments, the voltage conversion device includes a current transformer.

[0135] Optionally, in some embodiments, obtaining the target parameters through the speed measuring device connected to the synchronous motor includes: obtaining a plurality of consecutive target parameters through the speed measuring device; determining the grid frequency based on the target parameters includes: determining the grid frequency based on the average value of the plurality of consecutive target parameters.

[0136] It should be understood that the method 300 shown in FIG3 can be performed by the power grid frequency measurement device 100 in the foregoing embodiments. The synchronous motor, speed measurement device, and voltage conversion device in method 300 can be the synchronous motor 110, speed measurement device 120, and voltage conversion device 130 in the power grid frequency measurement device 100. It should be understood that the steps or operations in FIG3 are merely examples, and other operations or variations of the various operations in FIG3 can also be performed in the embodiments of this application.

[0137] Figure 4 shows a schematic block diagram of a power grid frequency measurement apparatus 400 according to an embodiment of this application. As shown in Figure 4, the power grid frequency measurement apparatus 400 may include:

[0138] The power supply unit 410 is used to supply power to the synchronous motor through the power grid so that the synchronous motor rotates under the power drive of the power grid.

[0139] The processing unit 420 is used to acquire target parameters, which indicate the power grid frequency, through a speed measuring device connected to the synchronous motor.

[0140] The processing unit 420 is further configured to determine the power grid frequency based on the target parameters.

[0141] Optionally, in this embodiment of the application, the processing unit 420 is further configured to: control the energy storage device to discharge when the current grid frequency is lower than the previous grid frequency; and control the energy storage device to charge when the current grid frequency is higher than the previous grid frequency.

[0142] Optionally, in this embodiment, the speed measuring device includes a rotating optical device, and the processing unit 420 is specifically used to: obtain the period or frequency of the output signal of the rotating optical device through the rotating optical device coaxially connected to the synchronous motor; and determine the power grid frequency based on the period or frequency of the output signal.

[0143] Optionally, in this embodiment of the application, the rotary optical device includes a rotary photoelectric encoder, and the output signal includes the pulse signal output by the photoelectric encoder.

[0144] Optionally, in this embodiment of the application, the power grid frequency f satisfies the following formula:

[0145] Wherein, T1 is the period of the pulse signal, k1 and k2 are constants, k1 is determined based on the synchronous motor, k2 is determined based on the rotary photoelectric encoder, and k2 is greater than or equal to 300.

[0146] Optionally, in this embodiment of the application, the speed measuring device includes a DC motor, and the processing unit 420 is specifically used to: acquire the voltage signal output by the DC motor through the DC motor coaxially connected to the synchronous motor; and determine the power grid frequency based on the voltage signal.

[0147] In some possible implementations, the power grid frequency f satisfies the following formula:

[0148] Wherein, U is the amplitude of the voltage signal, k1 and k3 are constants, k1 is determined based on the synchronous motor, and k3 is determined based on the DC motor.

[0149] Optionally, in the embodiments of this application, k1 is greater than or equal to 1.

[0150] Optionally, in this embodiment, the processing unit 420 is further configured to: control the high-voltage end of the voltage conversion device to draw power from the AC bus of the power grid; control the voltage conversion device to transfer the power drawn from the AC bus to the low-voltage end of the voltage conversion device; the power supply unit 410 is specifically configured to: use the low-voltage end to supply power to the synchronous motor.

[0151] Optionally, in an embodiment of this application, the voltage conversion device includes a current transformer.

[0152] Optionally, in this embodiment of the application, the processing unit 420 is specifically used to: acquire a plurality of consecutive target parameters through the speed measuring device; and determine the power grid frequency based on the average value of the plurality of consecutive target parameters.

[0153] It should be understood that the device 400 for measuring the power grid frequency can perform the corresponding operations in the method 300, and for the sake of brevity, it will not be described in detail here.

[0154] Figure 5 is a schematic diagram of the hardware structure of a power grid frequency measurement device 500 according to an embodiment of this application. The power grid frequency measurement device 500 includes a memory 501, a processor 502, a communication interface 503, and a bus 504. The memory 501, processor 502, and communication interface 503 are interconnected via the bus 504.

[0155] The memory 501 may be a read-only memory (ROM), a static storage device, or a random access memory (RAM). The memory 501 may store a program, and when the program stored in the memory 501 is executed by the processor 502, the processor 502 and the communication interface 503 are used to execute the various steps of the power grid frequency measurement method of the embodiments of this application.

[0156] The processor 502 may be a general-purpose central processing unit (CPU), microprocessor, application-specific integrated circuit (ASIC), graphics processing unit (GPU), or one or more integrated circuits, used to execute relevant programs to achieve the functions required by the units in the apparatus of this application embodiment, or to execute the power grid frequency measurement method of this application embodiment.

[0157] The processor 502 can also be an integrated circuit chip with signal processing capabilities. In implementation, each step of the power grid frequency measurement method of this application embodiment can be completed by the integrated logic circuitry in the processor 502 or by software instructions.

[0158] The processor 502 described above can also be a general-purpose processor, a digital signal processor (DSP), an ASIC, a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly implemented by the hardware processor, or implemented by a combination of hardware and software modules in the processor. The software modules can be located in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory 501. The processor 502 reads the information in memory 501 and, in conjunction with its hardware, completes the functions required by the units included in the power grid frequency measurement apparatus 500 of the embodiments of this application, or executes the power grid frequency measurement method of the embodiments of this application.

[0159] The communication interface 503 uses transceiver devices, such as, but not limited to, transceivers, to enable communication between the power grid frequency measurement device 500 and other devices or communication networks.

[0160] Bus 504 may include a pathway for transmitting information between various components of the power grid frequency measurement device 500 (e.g., memory 501, processor 502, communication interface 503).

[0161] It should be noted that although the above-described power grid frequency measurement device 500 only shows a memory, processor, and communication interface, those skilled in the art should understand that in specific implementations, the power grid frequency measurement device 500 may also include other devices necessary for normal operation. Furthermore, depending on specific needs, those skilled in the art should understand that the power grid frequency measurement device 500 may also include hardware devices for implementing other additional functions. In addition, those skilled in the art should understand that the power grid frequency measurement device 500 may only include the devices necessary for implementing the embodiments of this application, and not necessarily all the devices shown in FIG. 5.

[0162] This application also provides a computer-readable storage medium for storing a computer program for performing the methods described in the various embodiments of this application.

[0163] The aforementioned computer-readable storage medium may be a transient computer-readable storage medium or a non-transitory computer-readable storage medium.

[0164] This application also provides a computer program product, which includes a computer program stored on a computer-readable storage medium. The computer program includes program instructions that, when executed by a computer, cause the computer to perform the above-described power grid frequency measurement and control method.

[0165] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A device for measuring power grid frequency, characterized in that, include: A synchronous motor is configured to be connected to a power grid and rotate under the electric drive of the power grid; A speed measuring device is configured to connect to the synchronous motor and output a target parameter based on the speed of the synchronous motor, the target parameter indicating the grid frequency.

2. The apparatus according to claim 1, characterized in that, The speed measuring device includes a rotating optical device, which is coaxially connected to the synchronous motor. The target parameter includes the period or frequency of the output signal of the rotating optical device.

3. The apparatus according to claim 2, characterized in that, The rotary optical device includes a rotary photoelectric encoder, and the output signal includes a pulse signal.

4. The apparatus according to claim 3, characterized in that, The power grid frequency f satisfies the following formula: Wherein, T1 is the period of the pulse signal, k1 and k2 are constants, k1 is determined based on the synchronous motor, k2 is determined based on the rotary photoelectric encoder, and k2 is greater than or equal to 300.

5. The apparatus according to claim 1, characterized in that, The speed measuring device includes a DC motor, which is coaxially connected to the synchronous motor, and the target parameter includes the voltage signal output by the DC motor.

6. The apparatus according to claim 5, characterized in that, The power grid frequency f satisfies the following formula: Wherein, U is the amplitude of the voltage signal, k1 and k3 are constants, k1 is determined based on the synchronous motor, and k3 is determined based on the DC motor.

7. The apparatus according to claim 4 or 6, characterized in that, k1 is greater than or equal to 1.

8. The apparatus according to any one of claims 1 to 7, characterized in that, Also includes: A voltage conversion device is provided, wherein the high-voltage end of the voltage conversion device is connected to the AC bus of the power grid, and the low-voltage end of the voltage conversion device is connected to the synchronous motor, so that the synchronous motor rotates under the drive of the low-voltage end.

9. The apparatus according to claim 8, characterized in that, The voltage conversion device includes a current transformer.

10. The apparatus according to any one of claims 1 to 9, characterized in that, The speed measuring device is configured to output a series of target parameters based on the speed of the synchronous motor, the series of target parameters being used to indicate the power grid frequency.

11. A method for measuring power grid frequency, characterized in that, include: The synchronous motor is powered by the power grid so that it rotates under the power of the power grid. The target parameter, which indicates the power grid frequency, is obtained by a speed measuring device connected to the synchronous motor. The power grid frequency is determined based on the target parameters.

12. The method according to claim 11, characterized in that, The speed measuring device includes a rotating optical device. The speed measuring device, connected to the synchronous motor, acquires target parameters, including: The period or frequency of the output signal of the rotating optical device is obtained by using the rotating optical device coaxially connected to the synchronous motor. Determining the power grid frequency based on the target parameters includes: The power grid frequency is determined based on the period or frequency of the output signal.

13. The method according to claim 12, characterized in that, The rotary optical device includes a rotary photoelectric encoder, and the output signal includes a pulse signal.

14. The method according to claim 13, characterized in that, The power grid frequency f satisfies the following formula: Wherein, T1 is the period of the pulse signal, k1 and k2 are constants, k1 is determined based on the synchronous motor, k2 is determined based on the rotary photoelectric encoder, and k2 is greater than or equal to 300.

15. The method according to claim 11, characterized in that, The speed measuring device includes a DC motor. The speed measuring device connected to the synchronous motor acquires target parameters, including: The voltage signal output by the DC motor is obtained through the DC motor coaxially connected to the synchronous motor; Determining the power grid frequency based on the target parameters includes: The power grid frequency is determined based on the voltage signal.

16. The method according to claim 15, characterized in that, The power grid frequency f satisfies the following formula: Wherein, U is the amplitude of the voltage signal, k1 and k3 are constants, k1 is determined based on the synchronous motor, and k3 is determined based on the DC motor.

17. The method according to claim 14 or 16, characterized in that, k1 is greater than or equal to 1.

18. The method according to any one of claims 11 to 17, characterized in that, The method further includes: The high-voltage end of the control voltage conversion device draws power from the AC bus of the power grid; The voltage conversion device is controlled to transfer the electrical energy obtained from the AC bus to the low-voltage terminal of the voltage conversion device. The method of supplying power to the synchronous motor via the power grid includes: The synchronous motor is powered using the low-voltage terminal.

19. The method according to claim 18, characterized in that, The voltage conversion device includes a current transformer.

20. The method according to any one of claims 11 to 19, characterized in that, The acquisition of target parameters via a speed measuring device connected to the synchronous motor includes: The rotational speed measuring device acquires a series of target parameters. Determining the power grid frequency based on the target parameters includes: The power grid frequency is determined based on the average value of a series of target parameters.

21. The method according to any one of claims 11 to 20, characterized in that, The method further includes: If the current grid frequency is lower than the previous grid frequency, control the energy storage device to discharge. If the current grid frequency is greater than the previous grid frequency, the energy storage device is controlled to charge.

22. A computer and a readable storage medium, characterized in that, Used to store a computer program that causes a computer to perform a method for measuring power grid frequency as described in any one of claims 11 to 21.

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