A small hydropower frequency modulation method, device, equipment and medium

Abstract

The application discloses a small hydropower frequency regulation method, device, equipment and medium. The small hydropower frequency regulation method comprises the following steps: acquiring an off-grid initial frequency and a frequency stability interval of small hydropower; determining an initial to-be-adjusted output according to the off-grid initial frequency and a power shortage adjustment coefficient, and determining a first to-be-adjusted output and a first to-be-adjusted frequency according to the initial to-be-adjusted output; acquiring a frequency change rate when the small hydropower performs output adjustment according to the first to-be-adjusted output and the first to-be-adjusted frequency; determining a second to-be-adjusted output and a second to-be-adjusted frequency according to the frequency stability interval and the frequency change rate, so that the small hydropower works according to the second to-be-adjusted output and the second to-be-adjusted frequency. The technical scheme of the embodiment of the application can refine the frequency regulation strategy, stabilize the working frequency of the micro-grid and improve the power quality.

Description

Technical Field

[0001] This invention relates to the field of microgrid technology, and in particular to a method, apparatus, equipment and medium for frequency regulation of small hydropower. Background Technology

[0002] Small hydropower, as a widely distributed renewable energy source, is extensively used in areas rich in water resources. Especially in remote areas, the use of small hydropower not only ensures the reliability of power supply for residents but also helps reduce losses in long-distance transmission lines of the power distribution network.

[0003] Currently, small hydropower is generally in an extensive power generation state. After small hydropower is connected to the grid, it usually adopts the maximum power generation mode. Due to the support of the large grid, the voltage and frequency are relatively stable. However, when the main power supply line is disconnected due to a fault, that is, when the small hydropower is disconnected from the grid and forms an island system, the small hydropower units mostly operate in the off-grid state.

[0004] Due to issues such as investment and control strategies, most small hydropower stations will be unable to regulate their frequencies independently when the main power supply line is disconnected due to a fault. Even if some small hydropower stations are able to regulate their frequencies, they can only adjust the frequency according to a single frequency regulation method (high-frequency water reduction and low-frequency water addition), resulting in large frequency fluctuations in the microgrid and failure to meet grid standards. Summary of the Invention

[0005] This invention provides a method, apparatus, equipment, and medium for frequency regulation of small hydropower, which can refine the frequency regulation strategy, stabilize the operating frequency of the microgrid, and improve power quality.

[0006] According to one aspect of the present invention, a method for frequency regulation of small hydropower stations is provided, comprising:

[0007] Obtain the initial off-grid frequency and frequency stability range of small hydropower stations;

[0008] Based on the initial off-grid frequency and the power deficit adjustment coefficient, the initial output to be adjusted is determined, and based on the initial output to be adjusted, the first output to be adjusted and the first frequency to be adjusted are determined.

[0009] Obtain the frequency change rate when the small hydropower station adjusts its output according to the first output to be regulated and the first frequency to be regulated.

[0010] Based on the frequency stability range and the frequency change rate, the second output to be regulated and the second frequency to be regulated are determined so that the small hydropower station can operate according to the second output to be regulated and the second frequency to be regulated.

[0011] According to another aspect of the present invention, a small hydropower frequency regulation device is provided, comprising:

[0012] The data acquisition module is used to acquire the initial off-grid frequency and frequency stability range of small hydropower stations.

[0013] The first output and frequency determination module is used to determine the initial output to be adjusted based on the initial off-grid frequency and the power deficit adjustment coefficient, and to determine the first output to be adjusted and the first frequency to be adjusted based on the initial output to be adjusted.

[0014] The frequency change rate determination module is used to obtain the frequency change rate when the small hydropower station adjusts its output according to the first output to be adjusted and the first frequency to be adjusted.

[0015] The second output and frequency determination module is used to determine the second output to be adjusted and the second frequency to be adjusted based on the frequency stability range and the frequency change rate, so that the small hydropower station can operate according to the second output to be adjusted and the second frequency to be adjusted.

[0016] According to another aspect of the present invention, an electronic device is provided, the electronic device comprising:

[0017] At least one processor; and

[0018] A memory communicatively connected to the at least one processor; wherein,

[0019] The memory stores a computer program that can be executed by the at least one processor, which enables the at least one processor to perform the small hydropower frequency regulation method according to any embodiment of the present invention.

[0020] According to another aspect of the present invention, a computer-readable storage medium is provided, the computer-readable storage medium storing computer instructions for causing a processor to execute and implement the small hydropower frequency regulation method according to any embodiment of the present invention.

[0021] The technical solution of this invention obtains the initial off-grid frequency and frequency stability range of a small hydropower station, then determines the initial output to be adjusted based on the initial off-grid frequency and power deficit adjustment coefficient, and determines the first output to be adjusted and the first frequency to be adjusted based on the initial output to be adjusted, thereby obtaining the frequency change rate when the small hydropower station adjusts its output according to the first output to be adjusted and the first frequency to be adjusted, and further determines the second output to be adjusted and the second frequency to be adjusted based on the frequency stability range and the frequency change rate, so that the small hydropower station operates according to the second output to be adjusted and the second frequency to be adjusted. By using the frequency stability range and the frequency change rate of small hydropower, the first adjustable output and the first adjustable frequency previously set for small hydropower are adjusted to the second adjustable output and the second adjustable frequency. This achieves fine-grained frequency adjustment, rather than simply reducing water flow at high frequencies (lowering the operating frequency of small hydropower when the frequency is high) and increasing water flow at low frequencies (increasing the operating frequency of small hydropower when the frequency is low). This reduces the operating frequency of small hydropower and improves the frequency stability of the small hydropower microgrid system. It solves the problem of large frequency fluctuations and unacceptable power quality caused by the existing single frequency regulation method of small hydropower. It can refine the frequency regulation strategy, stabilize the operating frequency of the microgrid, and improve power quality.

[0022] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A flowchart of a small hydropower frequency regulation method is provided in Embodiment 1 of the present invention;

[0025] Figure 2 This is a flowchart of a small hydropower frequency regulation method provided in Embodiment 2 of the present invention;

[0026] Figure 3 This is a schematic diagram of the structure of a small hydropower frequency regulation device provided in Embodiment 3 of the present invention;

[0027] Figure 4 A schematic diagram of an electronic device that can be used to implement embodiments of the present invention is shown. Detailed Implementation

[0028] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0029] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0030] Example 1

[0031] Figure 1 This is a flowchart of a small hydropower frequency regulation method provided in Embodiment 1 of the present invention. This embodiment is applicable to situations where the small hydropower frequency regulation strategy is refined. This method can be executed by a small hydropower frequency regulation device, which can be implemented in hardware and / or software and can be configured in an electronic device. Figure 1 As shown, the method includes:

[0032] S110. Obtain the initial off-grid frequency and frequency stability range of small hydropower stations.

[0033] The initial off-grid frequency can be the frequency of the isolated system formed after the small hydropower station is disconnected from the main power supply line. The frequency stability range can be a pre-set frequency range. Optionally, the frequency stability range can be [49.5Hz, 50.5Hz]. This embodiment of the invention does not limit the specific values ​​corresponding to the upper and lower limits of the frequency stability range; the range given above is only an example.

[0034] In this embodiment of the invention, when the main power supply line is disconnected, the initial off-grid frequency of the small hydropower station can be collected, and then a stable frequency range that allows the small hydropower station to operate normally can be set according to its operational requirements.

[0035] S120. Based on the initial off-grid frequency and the power deficit adjustment coefficient, determine the initial output to be adjusted, and based on the initial output to be adjusted, determine the first output to be adjusted and the first frequency to be adjusted.

[0036] The power deficit adjustment coefficient can be set according to the operating parameters of the small hydropower station. The initial output to be adjusted can be the output calculated based on the power deficit of the small hydropower station. The first output to be adjusted can be the output of the small hydropower station output by the small hydropower governor after the initial output to be adjusted is input to the small hydropower governor. The first frequency to be adjusted can be the operating frequency of the small hydropower station output by the small hydropower governor after the initial output to be adjusted is input to the small hydropower governor.

[0037] In this embodiment of the invention, the initial output to be adjusted can be determined based on the off-grid initial frequency, the power deficit adjustment coefficient, and the power deficit calculation method. Then, the initial output to be adjusted is input to the small hydropower speed controller, and the output result of the small hydropower speed controller is analyzed to obtain the first output to be adjusted and the first frequency to be adjusted.

[0038] S130. Obtain the frequency change rate when the small hydropower station adjusts its output according to the first output to be adjusted and the first frequency to be adjusted.

[0039] The frequency change rate can be the ratio of the frequency change of a small hydropower station to the time that produces the frequency change.

[0040] In this embodiment of the invention, the small hydropower speed regulator can send the first output to be regulated and the first frequency to be regulated to the generator of the small hydropower, so that the generator of the small hydropower can work according to the first output to be regulated and the first frequency to be regulated. Then, the operating frequency of the small hydropower is sampled according to a certain sampling frequency, and the frequency change rate when the output of the small hydropower is regulated according to the first output to be regulated and the first frequency to be regulated is calculated based on the sampled frequency.

[0041] S140. Based on the frequency stability range and the frequency change rate, determine the second output to be regulated and the second frequency to be regulated, so that the small hydropower station operates according to the second output to be regulated and the second frequency to be regulated.

[0042] The second output to be adjusted can be the small hydropower output determined based on the frequency stability range and the frequency change rate. The second frequency to be adjusted can be the operating frequency of the small hydropower station determined based on the frequency stability range and the frequency change rate.

[0043] In this embodiment of the invention, the operating status of a small hydropower station can be distinguished based on the frequency stability range and the frequency change rate. Based on the operating status of the small hydropower station and the power deficit calculation method, a second adjustable output and a second adjustable frequency are calculated to ensure the small hydropower station operates according to these parameters. Furthermore, the current frequency change rate of the small hydropower station is acquired every preset time interval. Based on the current frequency change rate and the frequency stability range, the second adjustable output and the second adjustable frequency are updated to ensure the small hydropower station operates according to the updated parameters until the frequency change rate stabilizes within a preset range and the operating frequency stabilizes within the frequency stability range.

[0044] The technical solution of this invention obtains the initial off-grid frequency and frequency stability range of a small hydropower station, then determines the initial output to be adjusted based on the initial off-grid frequency and power deficit adjustment coefficient, and determines the first output to be adjusted and the first frequency to be adjusted based on the initial output to be adjusted, thereby obtaining the frequency change rate when the small hydropower station adjusts its output according to the first output to be adjusted and the first frequency to be adjusted, and further determines the second output to be adjusted and the second frequency to be adjusted based on the frequency stability range and the frequency change rate, so that the small hydropower station operates according to the second output to be adjusted and the second frequency to be adjusted. By using the frequency stability range and the frequency change rate of small hydropower, the first adjustable output and the first adjustable frequency previously set for small hydropower are adjusted to the second adjustable output and the second adjustable frequency. This achieves fine-grained frequency adjustment, rather than simply reducing water flow at high frequencies (lowering the operating frequency of small hydropower when the frequency is high) and increasing water flow at low frequencies (increasing the operating frequency of small hydropower when the frequency is low). This reduces the operating frequency of small hydropower and improves the frequency stability of the small hydropower microgrid system. It solves the problem of large frequency fluctuations and unacceptable power quality caused by the existing single frequency regulation method of small hydropower. It can refine the frequency regulation strategy, stabilize the operating frequency of the microgrid, and improve power quality.

[0045] Example 2

[0046] Figure 2 This is a flowchart of a small hydropower frequency regulation method provided in Embodiment 2 of the present invention. Based on the above embodiments, this embodiment provides specific optional implementation methods for obtaining the frequency change rate when the small hydropower station adjusts its output according to a first adjustable output and a first adjustable frequency. For example... Figure 2 As shown, the method includes:

[0047] S210, Obtain the initial off-grid frequency and frequency stability range of small hydropower.

[0048] S220. Based on the initial off-grid frequency and the power deficit adjustment coefficient, determine the initial output to be adjusted, and based on the initial output to be adjusted, determine the first output to be adjusted and the first frequency to be adjusted.

[0049] In an optional embodiment of the present invention, determining the initial output to be regulated based on the initial off-grid frequency and the power deficit adjustment coefficient may include: obtaining the standard off-grid frequency; calculating the target difference between the standard off-grid frequency and the initial off-grid frequency, and calculating the target product of the target difference and the power deficit adjustment coefficient; and determining the initial output to be regulated based on the target product.

[0050] The standard off-grid frequency can be a pre-set frequency value. Optionally, the standard off-grid frequency can be the midpoint of a frequency stability range. For example, the standard off-grid frequency can be set to 50Hz, etc., but this embodiment of the invention does not set a specific value for the standard off-grid frequency. The target difference can be the difference between the standard off-grid frequency and the initial off-grid frequency. The target product can be the product of the target difference and the power deficit adjustment coefficient.

[0051] In this embodiment of the invention, a standard off-grid frequency can be set according to the working needs of small hydropower, and the load power of small hydropower can be collected through data acquisition equipment. Then, the difference between the standard off-grid frequency and the initial off-grid frequency can be calculated as the target difference. The product of the target difference and the power deficit adjustment coefficient can be calculated as the target product. Furthermore, the initial output to be adjusted can be determined based on the target product.

[0052] Optionally, 50% of the target product can be used as the initial output to be adjusted. This embodiment of the invention does not limit the percentage of the initial output to be adjusted relative to the target product.

[0053] S230. Obtain the frequency change rate when the small hydropower station adjusts its output according to the first output to be adjusted and the first frequency to be adjusted.

[0054] In an optional embodiment of the present invention, S230 may include:

[0055] S231. Set the frequency sampling time interval.

[0056] The frequency sampling time interval can be the time interval for collecting the operating frequency of a small hydropower station. Optionally, the frequency sampling time interval can be, but is not limited to, 500ms.

[0057] In this embodiment of the invention, the frequency sampling time interval can be set according to the actual operation of the small hydropower station.

[0058] S232. Based on the current sampling time and frequency sampling time interval, determine the first sampling frequency and the second sampling frequency when the small hydropower station adjusts its output according to the first output to be adjusted and the first frequency to be adjusted.

[0059] The first sampling frequency can be the operating frequency of the small hydropower station at the current sampling moment when it adjusts its output according to the first adjustable output and the first adjustable frequency. The second sampling frequency can be the operating frequency of the small hydropower station at the moment corresponding to the sampling time interval of the previous frequency at the current sampling moment. Both the first and second sampling frequencies are the operating frequencies of the small hydropower station when it adjusts its output according to the first adjustable output and the first adjustable frequency. For example, assuming the moment when the small hydropower station adjusts its output according to the first adjustable output and the first adjustable frequency is 'a', the sampling moment of the first sampling frequency is 'b', the sampling moment of the second sampling frequency is 'c', and the sampling time interval is 'd', then there exists a <b<c,c=b+d。

[0060] In this embodiment of the invention, when the small hydropower station adjusts its output according to the first adjustable output and the first adjustable frequency, the operating frequency of the small hydropower station at the current sampling time can be collected as the first sampling frequency, and the operating frequency of the small hydropower station collected at the time corresponding to the previous frequency sampling time interval at the current sampling time can be determined to obtain the second sampling frequency.

[0061] S233. Determine the frequency change rate based on the first sampling frequency, the second sampling frequency, and the frequency sampling time interval.

[0062] In this embodiment of the invention, the difference between the first sampling frequency and the second sampling frequency can be calculated first, and then the ratio of the difference to the frequency sampling time interval can be calculated. The calculated ratio can then be used as the frequency change rate when the first frequency to be adjusted is used for output adjustment.

[0063] S240. Based on the frequency stability range and the frequency change rate, determine the second output to be regulated and the second frequency to be regulated, so that the small hydropower station operates according to the second output to be regulated and the second frequency to be regulated.

[0064] In an optional embodiment of the present invention, before determining the second output to be adjusted and the second frequency to be adjusted based on the frequency stability range and the frequency change rate, the method may further include: setting a change type discrimination threshold and a change rate error threshold for the frequency change rate; and determining the change type discrimination range based on the change type discrimination threshold and the change rate error threshold.

[0065] The change type discrimination threshold can be a pre-set positive number used to determine the rate of change of frequency. The change rate error threshold can be a pre-set absolute value of the allowed frequency error. The change type discrimination interval can be a data range determined based on the change type discrimination threshold and the change rate error threshold.

[0066] In this embodiment of the invention, a threshold for the change type of frequency change rate and a threshold for the change rate error can be set according to the output adjustment needs of small hydropower. Then, the sum of the change type threshold and the change rate error threshold is used as the upper limit of the change type discrimination interval, and the opposite of the sum is used as the lower limit of the change type discrimination interval. Thus, the change type discrimination interval is determined based on the upper limit and the lower limit of the change type discrimination interval.

[0067] For example, assuming the threshold for determining the type of change is 0.1 and the threshold for the error of the rate of change is 0.1, then the upper limit of the interval for determining the type of change is 0.2 (0.1 + 0.1), and the lower limit of the interval for determining the type of change is -0.2, that is, the interval for determining the type of change is [-0.2, 0.2].

[0068] In an optional embodiment of the present invention, determining the second output to be adjusted and the second frequency to be adjusted based on the frequency stability range and the frequency change rate may include: when the first frequency to be adjusted is located in the frequency stability range and the frequency change rate is located in the change type discrimination range, taking the first output to be adjusted as the second output to be adjusted and the first frequency to be adjusted as the second frequency to be adjusted; when the first frequency to be adjusted is located in the frequency stability range and the frequency change rate is greater than the upper limit of the change type discrimination range, or when the first frequency to be adjusted is located in the frequency stability range and the frequency change rate is less than the lower limit of the change type discrimination range, determining the target output based on the power deficit adjustment coefficient and the small hydropower to be adjusted frequency, and determining the second output to be adjusted and the second frequency to be adjusted based on the target output.

[0069] The upper limit of the type discrimination can be the upper limit of the change type discrimination interval. The lower limit of the type discrimination can be the lower limit of the change type discrimination interval. The frequency to be adjusted for small hydropower can be the current operating frequency of the small hydropower station collected after determining whether the frequency change rate is within the change type discrimination interval. The target output can be the output determined based on the power deficit adjustment coefficient and the frequency to be adjusted for small hydropower, used to calculate the second output to be adjusted and the second frequency to be adjusted.

[0070] In this embodiment of the invention, it can be first determined whether the first frequency to be adjusted is within the frequency stability range and whether the frequency change rate is within the change type discrimination range. If the first frequency to be adjusted is within the frequency stability range and the frequency change rate is within the change type discrimination range, then the first output to be adjusted is used as the second output to be adjusted, and the first frequency to be adjusted is used as the second frequency to be adjusted. If the first frequency to be adjusted is within the frequency stability range and the frequency change rate is greater than the upper limit of the change type discrimination range, or if the first frequency to be adjusted is within the frequency stability range and the frequency change rate is less than the lower limit of the change type discrimination range, then the difference between the standard off-grid frequency and the small hydropower station's frequency to be adjusted, and the product of this difference and the power deficit adjustment coefficient, are calculated. The product value is then used as the value corresponding to the target output, and the value corresponding to the target output is input to the small hydropower station speed controller, so that the small hydropower station speed controller can output the second output to be adjusted and the second frequency to be adjusted.

[0071] In an optional embodiment of the present invention, determining the second output to be adjusted and the second frequency to be adjusted based on the frequency stability range and the frequency change rate may include: when the first frequency to be adjusted is greater than the upper limit of the frequency stability range and the frequency change rate is less than the lower limit of the type discrimination range, the first output to be adjusted is taken as the second output to be adjusted, and the first frequency to be adjusted is taken as the second frequency to be adjusted; when the first frequency to be adjusted is greater than the upper limit of the frequency stability range and the frequency change rate is greater than the upper limit of the type discrimination range, or when the first frequency to be adjusted is greater than the upper limit of the frequency stability range and the frequency change rate is within the type discrimination range, the target output is determined based on the power deficit adjustment coefficient and the small hydropower station's frequency to be adjusted, and the second output to be adjusted and the second frequency to be adjusted are determined based on the target output.

[0072] The upper limit of frequency stability can be the upper frequency of the frequency stability range.

[0073] In this embodiment of the invention, if the first frequency to be adjusted is greater than the upper limit of the frequency stability range and the rate of frequency change is less than the lower limit of the type discrimination range, then the first output to be adjusted is taken as the second output to be adjusted, and the first frequency to be adjusted is taken as the second frequency to be adjusted. If the first frequency to be adjusted is greater than the upper limit of the frequency stability range and the rate of frequency change is greater than the upper limit of the type discrimination range, or if the first frequency to be adjusted is greater than the upper limit of the frequency stability range and the rate of frequency change is within the type discrimination range, then the difference between the standard off-grid frequency and the small hydropower station's frequency to be adjusted, and the product of this difference and the power deficit adjustment coefficient, are calculated. The product value is then used as the value corresponding to the target output, and the value corresponding to the target output is input to the small hydropower station speed controller, so that the small hydropower station speed controller can output the second output to be adjusted and the second frequency to be adjusted.

[0074] In an optional embodiment of the present invention, determining the second output to be adjusted and the second frequency to be adjusted based on the frequency stability range and the frequency change rate may include: when the first frequency to be adjusted is less than the lower limit of frequency stability in the frequency stability range and the frequency change rate is greater than the upper limit of type discrimination in the change type discrimination range, the first output to be adjusted is taken as the second output to be adjusted, and the first frequency to be adjusted is taken as the second frequency to be adjusted; when the first frequency to be adjusted is less than the lower limit of frequency stability in the frequency stability range and the frequency change rate is less than the lower limit of type discrimination in the change type discrimination range, or when the first frequency to be adjusted is less than the lower limit of frequency stability in the frequency stability range and the frequency change rate is within the change type discrimination range, the target output is determined based on the power deficit adjustment coefficient and the small hydropower to be adjusted frequency, and the second output to be adjusted and the second frequency to be adjusted are determined based on the target output.

[0075] The lower limit of frequency stability can be the lower limit frequency of the frequency stability range.

[0076] In this embodiment of the invention, if the first frequency to be adjusted is less than the lower limit of frequency stability in the frequency stability interval, and the rate of frequency change is greater than the upper limit of type discrimination in the change type discrimination interval, then the first output to be adjusted is taken as the second output to be adjusted, and the first frequency to be adjusted is taken as the second frequency to be adjusted. If the first frequency to be adjusted is less than the lower limit of frequency stability in the frequency stability interval, and the rate of frequency change is less than the lower limit of type discrimination in the change type discrimination interval, or if the first frequency to be adjusted is less than the lower limit of frequency stability in the frequency stability interval, and the rate of frequency change is within the change type discrimination interval, then the difference between the standard off-grid frequency and the small hydropower station's frequency to be adjusted, and the product of this difference and the power deficit adjustment coefficient, are calculated. The product value is then used as the value corresponding to the target output, and the value corresponding to the target output is input to the small hydropower station speed controller, so that the small hydropower station speed controller can output the second output to be adjusted and the second frequency to be adjusted.

[0077] In a specific example, the frequency regulation method for small hydropower stations is as follows:

[0078] Step 1: Collect the initial off-grid frequency f1 of the small hydropower station and the power output P1 when the small hydropower station is off-grid.

[0079] Step 2: Calculate the power deficit using the formula P. m =P ref +k(f ref -f m ), calculate the system power deficit, i.e., k(f ref -f m ), and uses 50% of the power deficit of the isolated system as the initial output to be regulated, while collecting the operating frequency of the small hydropower station every 500ms. Among them, P ref Let f be the power of the small hydropower load, k be the power deficit adjustment coefficient, and f be the load factor. ref For standard off-grid frequency, f m P represents the current operating frequency of small hydropower stations in the isolated system. m This represents the current power output of the turbine generator in the isolated system. When P... m With P ref When P is equal, the frequency of a small hydropower station is stable. m Greater than P ref The excess power generated will cause the generator rotor speed to increase, thus increasing the frequency; conversely, it will cause the frequency to decrease, i.e., f ref with f m There is a power deficit due to unequal timing.

[0080] Step 3: Input the initial output to be adjusted into the small hydropower speed controller to obtain the first output to be adjusted P2 and the first frequency to be adjusted f2.

[0081] Step 4: Assume the frequency stability range is [49.5Hz-50.5Hz], and the frequency change rate is... Δf is the difference between the first and second sampling frequencies, and Δt is the frequency sampling time interval. The rate of change error threshold is 0.1, meaning there is an allowable error band of ±0.1 for the frequency, and the change type discrimination interval is [-0.2, 0.2]. When Within the range [-0.2, 0.2], the frequency is considered to remain unchanged; when... If the value is greater than 0.2, the frequency is considered to be on the rise; when... If the value is less than -0.2, the frequency is considered to be decreasing.

[0082] When f2 is in the range [49.5Hz-50.5Hz], calculate like If the range is [-0.2, 0.2], the system is considered stable and no action is required; otherwise... A value greater than 0.2 indicates an increase in the frequency of small hydropower, requiring a reduction in turbine output. Specifically, the power deficit calculation formula can be used to calculate the power deficit and determine the second adjustable output P3 and the second adjustable frequency f3. If... If the value is less than -0.2, it indicates that the frequency of the small hydropower station has decreased, and the turbine output needs to be increased. The second output to be adjusted, P3, and the second frequency to be adjusted, f3, need to be determined. The principle for determining the second output to be adjusted, P3, and the second frequency to be adjusted, f3 is the same as above and will not be repeated here.

[0083] When f2 is greater than 50.5Hz, calculate like Within the range [-0.2, 0.2], this indicates that the operating frequency of the small hydropower station remains at a high level, requiring a reduction in turbine output and determination of f3 and P3; if A value greater than 0.2 indicates that the operating frequency of the small hydropower station continues to rise after exceeding the limit, requiring a faster reduction in turbine output and determination of f3 and P3; if When the value is below -0.2, it indicates that the operating frequency of small hydropower stations has decreased and no action is required.

[0084] When f2 is less than 49.5Hz, calculate like Within the range [-0.2, 0.2], it indicates that the operating frequency of small hydropower plants remains at a low level, requiring an increase in turbine output to determine f3 and P3; if A value greater than 0.2 indicates an increase in the operating frequency of small hydropower stations, requiring no action; if... If the value is less than -0.2, it indicates that the operating frequency of the small hydropower station is decreasing rapidly, and there is no need to accelerate the increase of the turbine output of the small hydropower station, thus determining f3 and P3.

[0085] The adjustment principle is shown in Table 1:

[0086] Table 1. Principle of Frequency Regulation in Small Hydropower Stations

[0087]

[0088] Step 5: Based on the adjustment principle in Step 4, update f3 and P3 so that the small hydropower station operates with the updated data.

[0089] As can be seen, this scheme refines the frequency regulation strategy, dividing the regulation mode into nine operating conditions based on the frequency stability range and the frequency change rate. By introducing the frequency change rate, the system frequency change trend can be predicted, effectively improving the frequency overshoot phenomenon. Furthermore, the system requires no action in three of these conditions, reducing the frequency of governor operation. In addition, four regulation modes—adding water, accelerating water addition, reducing water, and decelerating water reduction—are introduced, making the regulation more precise and thus stabilizing the system frequency.

[0090] The technical solution of this invention obtains the initial off-grid frequency and frequency stability range of a small hydropower station, thereby determining the initial output to be adjusted based on the initial off-grid frequency and power deficit adjustment coefficient. Based on the initial output to be adjusted, a first output to be adjusted and a first frequency to be adjusted are determined. Then, a frequency sampling time interval is set, and based on the current sampling time and the frequency sampling time interval, a first sampling frequency and a second sampling frequency are determined when the small hydropower station adjusts its output according to the first output to be adjusted and the first frequency to be adjusted. Further, based on the first sampling frequency, the second sampling frequency, and the frequency sampling time interval, the frequency change rate when adjusting the output at the first frequency to be adjusted is determined. Thus, based on the frequency stability range and the frequency change rate, a second output to be adjusted and a second frequency to be adjusted are determined, so that the small hydropower station operates according to the second output to be adjusted and the second frequency to be adjusted. By using the frequency stability range and the frequency change rate of small hydropower, the first adjustable output and the first adjustable frequency previously set for small hydropower are adjusted to the second adjustable output and the second adjustable frequency. This achieves fine-grained frequency adjustment, rather than simply reducing water flow at high frequencies (lowering the operating frequency of small hydropower when the frequency is high) and increasing water flow at low frequencies (increasing the operating frequency of small hydropower when the frequency is low). This reduces the operating frequency of small hydropower and improves the frequency stability of the small hydropower microgrid system. It solves the problem of large frequency fluctuations and unacceptable power quality caused by the existing single frequency regulation method of small hydropower. It can refine the frequency regulation strategy, stabilize the operating frequency of the microgrid, and improve power quality.

[0091] Example 3

[0092] Figure 3 This is a schematic diagram of a small hydropower frequency regulation device provided in Embodiment 3 of the present invention. Figure 3 As shown, the device includes: a data acquisition module 310, a first output and frequency determination module 320, a frequency change rate determination module 330, and a second output and frequency determination module 340, wherein...

[0093] The data acquisition module 310 is used to acquire the initial off-grid frequency and frequency stability range of small hydropower stations;

[0094] The first output and frequency determination module 320 is used to determine the initial output to be adjusted based on the initial off-grid frequency and the power deficit adjustment coefficient, and to determine the first output to be adjusted and the first frequency to be adjusted based on the initial output to be adjusted.

[0095] The frequency change rate determination module 330 is used to obtain the frequency change rate when the small hydropower station adjusts its output according to the first output to be adjusted and the first frequency to be adjusted.

[0096] The second output and frequency determination module 340 is used to determine the second output to be adjusted and the second frequency to be adjusted based on the frequency stability range and the frequency change rate, so that the small hydropower station can operate according to the second output to be adjusted and the second frequency to be adjusted.

[0097] The technical solution of this invention obtains the initial off-grid frequency and frequency stability range of a small hydropower station, then determines the initial output to be adjusted based on the initial off-grid frequency and power deficit adjustment coefficient, and determines the first output to be adjusted and the first frequency to be adjusted based on the initial output to be adjusted, thereby obtaining the frequency change rate when the small hydropower station adjusts its output according to the first output to be adjusted and the first frequency to be adjusted, and further determines the second output to be adjusted and the second frequency to be adjusted based on the frequency stability range and the frequency change rate, so that the small hydropower station operates according to the second output to be adjusted and the second frequency to be adjusted. By using the frequency stability range and the frequency change rate of small hydropower, the first adjustable output and the first adjustable frequency previously set for small hydropower are adjusted to the second adjustable output and the second adjustable frequency. This achieves fine-grained frequency adjustment, rather than simply reducing water flow at high frequencies (lowering the operating frequency of small hydropower when the frequency is high) and increasing water flow at low frequencies (increasing the operating frequency of small hydropower when the frequency is low). This reduces the operating frequency of small hydropower and improves the frequency stability of the small hydropower microgrid system. It solves the problem of large frequency fluctuations and unacceptable power quality caused by the existing single frequency regulation method of small hydropower. It can refine the frequency regulation strategy, stabilize the operating frequency of the microgrid, and improve power quality.

[0098] Optionally, the first output and frequency determination module 320 is used to obtain the standard off-grid frequency; calculate the target difference between the standard off-grid frequency and the initial off-grid frequency, and calculate the target product of the target difference and the power deficit adjustment coefficient; and determine the initial output to be adjusted based on the target product.

[0099] Optionally, the frequency change rate determination module 330 is used to set the frequency sampling time interval; determine the first sampling frequency and the second sampling frequency when the small hydropower station adjusts its output according to the first adjustable output and the first adjustable frequency based on the current sampling time and the frequency sampling time interval; and determine the frequency change rate based on the first sampling frequency, the second sampling frequency and the frequency sampling time interval.

[0100] Optionally, the small hydropower frequency regulation device further includes a change type discrimination interval determination module, used to set the change type discrimination threshold and the change rate error threshold of the frequency change rate; and to determine the change type discrimination interval based on the change type discrimination threshold and the change rate error threshold.

[0101] Optionally, the second output and frequency determination module 340 is used to determine the first output to be adjusted as the second output to be adjusted and the first frequency to be adjusted as the second frequency to be adjusted when the first frequency to be adjusted is in the frequency stable range and the frequency change rate is in the change type discrimination range; when the first frequency to be adjusted is in the frequency stable range and the frequency change rate is greater than the upper limit of the type discrimination range, or when the first frequency to be adjusted is in the frequency stable range and the frequency change rate is less than the lower limit of the type discrimination range, determine the target output based on the power deficit adjustment coefficient and the small hydropower to be adjusted frequency, and determine the second output to be adjusted and the second frequency to be adjusted based on the target output.

[0102] Optionally, the second output and frequency determination module 340 is used to determine the first output to be adjusted as the second output to be adjusted and the first frequency to be adjusted as the second frequency to be adjusted when the first frequency to be adjusted is greater than the upper limit of the frequency stability range and the frequency change rate is less than the lower limit of the type discrimination range of the change type discrimination range; when the first frequency to be adjusted is greater than the upper limit of the frequency stability range and the frequency change rate is greater than the upper limit of the type discrimination range of the change type discrimination range, or when the first frequency to be adjusted is greater than the upper limit of the frequency stability range and the frequency change rate is within the change type discrimination range, the target output is determined based on the power deficit adjustment coefficient and the small hydropower to be adjusted frequency, and the second output to be adjusted and the second frequency to be adjusted are determined based on the target output.

[0103] Optionally, the second output and frequency determination module 340 is used to determine the first output to be adjusted as the second output to be adjusted and the first frequency to be adjusted as the second frequency to be adjusted when the first frequency to be adjusted is less than the lower limit of frequency stability in the frequency stability range and the frequency change rate is greater than the upper limit of type discrimination in the change type discrimination range; when the first frequency to be adjusted is less than the lower limit of frequency stability in the frequency stability range and the frequency change rate is less than the lower limit of type discrimination in the change type discrimination range, or when the first frequency to be adjusted is less than the lower limit of frequency stability in the frequency stability range and the frequency change rate is within the change type discrimination range, the target output is determined based on the power deficit adjustment coefficient and the small hydropower to be adjusted frequency, and the second output to be adjusted and the second frequency to be adjusted are determined based on the target output.

[0104] The small hydropower frequency regulation device provided in the embodiments of the present invention can execute the small hydropower frequency regulation method provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the method.

[0105] Example 4

[0106] Figure 4 A schematic diagram of an electronic device that can be used to implement embodiments of the present invention is shown. The electronic device is intended to represent various forms of digital computers. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the invention described and / or claimed herein.

[0107] like Figure 4 As shown, the electronic device 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12 or a random access memory (RAM) 13, communicatively connected to the at least one processor 11. The memory stores computer programs executable by the at least one processor. The processor 11 can perform various appropriate actions and processes based on the computer program stored in the ROM 12 or loaded from storage unit 18 into the RAM 13. The RAM 13 may also store various programs and data required for the operation of the electronic device 10. The processor 11, ROM 12, and RAM 13 are interconnected via a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0108] Multiple components in electronic device 10 are connected to I / O interface 15, including: input unit 16, such as keyboard, mouse, etc.; output unit 17, such as various types of displays, speakers, etc.; storage unit 18, such as disk, optical disk, etc.; and communication unit 19, such as network card, modem, wireless transceiver, etc. Communication unit 19 allows electronic device 10 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0109] Processor 11 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. Processor 11 performs the various methods and processes described above, such as the small hydropower frequency regulation method.

[0110] In some embodiments, the small hydropower frequency regulation method may be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed on electronic device 10 via ROM 12 and / or communication unit 19. When the computer program is loaded into RAM 13 and executed by processor 11, one or more steps of the small hydropower frequency regulation method described above may be performed. Alternatively, in other embodiments, processor 11 may be configured to perform the small hydropower frequency regulation method by any other suitable means (e.g., by means of firmware).

[0111] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0112] Computer programs used to implement the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be performed. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0113] In the context of this invention, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0114] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the electronic device. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0115] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as data servers), or computing systems that include middleware components (e.g., application servers), or computing systems that include frontend components (e.g., user computers with graphical user interfaces or web browsers through which users can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., communication networks). Examples of communication networks include local area networks (LANs), wide area networks (WANs), blockchain networks, and the Internet.

[0116] A computing system can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a hosting product within the cloud computing service system to address the shortcomings of traditional physical hosts and VPS services, such as high management difficulty and weak business scalability.

[0117] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0118] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for frequency regulation in small hydropower stations, characterized in that, include: Obtain the initial off-grid frequency and frequency stability range of small hydropower stations; Based on the initial off-grid frequency and the power deficit adjustment coefficient, the initial output to be adjusted is determined, and based on the initial output to be adjusted, the first output to be adjusted and the first frequency to be adjusted are determined. Obtain the frequency change rate when the small hydropower station adjusts its output according to the first adjustable output and the first adjustable frequency; Based on the frequency stability range and the frequency change rate, the second output to be adjusted and the second frequency to be adjusted are determined so that the small hydropower station operates according to the second output to be adjusted and the second frequency to be adjusted. Before determining the second adjustable output and the second adjustable frequency based on the frequency stability range and the frequency change rate, the method further includes: Set a threshold for the type of change in the frequency change rate and a threshold for the change rate error; The change type discrimination interval is determined based on the change type discrimination threshold and the change rate error threshold; The step of determining the second output power to be adjusted and the second frequency to be adjusted based on the frequency stability range and the frequency change rate includes: When the first frequency to be adjusted is in the frequency stable range and the frequency change rate is in the change type discrimination range, the first output to be adjusted is taken as the second output to be adjusted, and the first frequency to be adjusted is taken as the second frequency to be adjusted. When the first frequency to be adjusted is in the frequency stable range and the frequency change rate is greater than the upper limit of the type discrimination range of the change type discrimination range, or when the first frequency to be adjusted is in the frequency stable range and the frequency change rate is less than the lower limit of the type discrimination range of the change type discrimination range, the target output is determined according to the power deficit adjustment coefficient and the small hydropower to be adjusted frequency, and the second output to be adjusted and the second frequency to be adjusted are determined according to the target output.

2. The method according to claim 1, characterized in that, The step of determining the initial output to be regulated based on the off-grid initial frequency and the power deficit adjustment coefficient includes: Obtain the standard off-grid frequency; Calculate the target difference between the standard off-grid frequency and the initial off-grid frequency, and calculate the target product of the target difference and the power deficit adjustment coefficient; The initial output force to be adjusted is determined based on the target product.

3. The method according to claim 2, characterized in that, The acquisition of the frequency change rate when the small hydropower station adjusts its output according to the first adjustable output and the first adjustable frequency includes: Set the frequency sampling time interval; Based on the current sampling time and the frequency sampling time interval, determine the first sampling frequency and the second sampling frequency when the small hydropower station adjusts its output according to the first output to be adjusted and the first frequency to be adjusted. The frequency change rate is determined based on the first sampling frequency, the second sampling frequency, and the frequency sampling time interval.

4. The method according to claim 1, characterized in that, The step of determining the second output power to be adjusted and the second frequency to be adjusted based on the frequency stability range and the frequency change rate includes: When the first adjustable frequency is greater than the upper limit of the frequency stability range and the frequency change rate is less than the lower limit of the change type discrimination range, the first adjustable output is used as the second adjustable output, and the first adjustable frequency is used as the second adjustable frequency. When the first frequency to be adjusted is greater than the upper limit of frequency stability in the frequency stability range and the rate of frequency change is greater than the upper limit of type discrimination in the change type discrimination range, or when the first frequency to be adjusted is greater than the upper limit of frequency stability in the frequency stability range and the rate of frequency change is within the change type discrimination range, the target output is determined based on the power deficit adjustment coefficient and the frequency to be adjusted for small hydropower, and the second output to be adjusted and the second frequency to be adjusted are determined based on the target output.

5. The method according to claim 1, characterized in that, The step of determining the second output power to be adjusted and the second frequency to be adjusted based on the frequency stability range and the frequency change rate includes: When the first adjustable frequency is less than the lower limit of frequency stability in the frequency stability range and the frequency change rate is greater than the upper limit of type discrimination in the change type discrimination range, the first adjustable output is used as the second adjustable output, and the first adjustable frequency is used as the second adjustable frequency. When the first frequency to be adjusted is less than the lower limit of frequency stability in the frequency stability range and the rate of frequency change is less than the lower limit of type discrimination in the change type discrimination range, or when the first frequency to be adjusted is less than the lower limit of frequency stability in the frequency stability range and the rate of frequency change is within the change type discrimination range, the target output is determined based on the power deficit adjustment coefficient and the frequency to be adjusted for small hydropower, and the second output to be adjusted and the second frequency to be adjusted are determined based on the target output.

6. A small hydropower frequency regulation device, characterized in that, include: The data acquisition module is used to acquire the initial off-grid frequency and frequency stability range of small hydropower stations. The first output and frequency determination module is used to determine the initial output to be adjusted based on the off-grid initial frequency and the power deficit adjustment coefficient, and to determine the first output to be adjusted and the first frequency to be adjusted based on the initial output to be adjusted. The frequency change rate determination module is used to obtain the frequency change rate when the small hydropower station adjusts its output according to the first output to be adjusted and the first frequency to be adjusted. The second output and frequency determination module is used to determine the second output to be adjusted and the second frequency to be adjusted based on the frequency stability range and the frequency change rate, so that the small hydropower station operates according to the second output to be adjusted and the second frequency to be adjusted. The change type discrimination interval determination module is used to set the change type discrimination threshold and the change rate error threshold of the frequency change rate; and to determine the change type discrimination interval based on the change type discrimination threshold and the change rate error threshold. The second output and frequency determination module is further configured to: when the first adjustable frequency is located in the frequency stability range and the frequency change rate is located in the change type discrimination range, use the first adjustable output as the second adjustable output and the first adjustable frequency as the second adjustable frequency; when the first adjustable frequency is located in the frequency stability range and the frequency change rate is greater than the upper limit of the type discrimination range, or when the first adjustable frequency is located in the frequency stability range and the frequency change rate is less than the lower limit of the type discrimination range, determine the target output based on the power deficit adjustment coefficient and the small hydropower adjustable frequency, and determine the second adjustable output and the second adjustable frequency based on the target output.

7. An electronic device, characterized in that, The electronic device includes: At least one processor; and A memory communicatively connected to the at least one processor; wherein, The memory stores a computer program that can be executed by the at least one processor, the computer program being executed by the at least one processor to enable the at least one processor to perform the small hydropower frequency regulation method according to any one of claims 1-5.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that are used to cause a processor to execute the small hydropower frequency regulation method according to any one of claims 1-5.

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