Capacitance setting method and equipment of filter and storage medium

Abstract

The invention discloses a capacitance setting method and device for a filter and a storage medium, and the method comprises the steps: calculating a working current flowing through a single-tuned filter under the condition that a harmonic wave is injected into the single-tuned filter; the single tuned filter comprises a capacitor and a reactor; calculating the rated capacity of the capacitor according to the working current; according to the rated capacity of the capacitor, calculating the rated voltage which can filter harmonic waves and is minimum in capacity for the capacitor; and setting the minimum capacity of the capacitor according to the rated voltage of the capacitor. According to the embodiment of the invention, the minimum capacity of the capacitor is calculated under the condition of keeping the harmonic filtering effect of the capacitor of the single-tuned filter, and the cost of the capacitor can be reduced, so that the cost of the single-tuned filter is reduced, and the cost is reduced on a large scale when a large number of low single-tuned filters are deployed in a power distribution network.

Description

Technical Field

[0001] The present invention relates to the field of electric power technology, and in particular to a capacitance setting method, device and storage medium of a filter. Background Art

[0002] The main features of urban power grid transformation are the ring network of urban power grid power supply and the cabling of distribution network. The cabling of distribution network is gradually dominated by cables laid underground.

[0003] The distributed capacitance of the cable to the ground is large, which causes a significant change in the frequency blocking characteristics of the power grid, making it easy for inductive and capacitive coupling to occur in the power grid, which may cause harmonic amplification and resonance.

[0004] In addition, with the promotion of distributed renewable energy generators, such as photovoltaic or wind power, their locations are generally far from the distribution network and often rely on cables for connection. Since the parasitic capacitance of cables is large, it is also easy to cause harmonic resonance problems in the distribution network.

[0005] At present, filters are configured in the distribution network to filter harmonics to prevent harmonics from inducing abnormal power consumption of generators on the low-voltage distribution network side.

[0006] However, the specifications of the filters are often high, and the cost is high when a large number of filters are deployed in the distribution network. Summary of the invention

[0007] In view of this, the present invention provides a method, device and storage medium for setting capacitance of a filter, so as to reduce the cost of the filter while maintaining the harmonic filtering effect of the filter.

[0008] A first aspect of the present invention provides a method for setting capacitance of a filter, comprising:

[0009] Under the condition of harmonic injection into a single tuned filter, calculating the operating current flowing through the single tuned filter; the single tuned filter includes a capacitor and a reactance;

[0010] Calculating the rated capacity of the capacitor according to the working current;

[0011] Calculate the rated voltage of the capacitor that can filter out harmonics and has the smallest capacity according to the rated capacity of the capacitor;

[0012] The minimum capacity of the capacitor is set according to the rated voltage of the capacitor.

[0013] Optionally, the operating current is expressed as:

[0014]

[0015] Among them, I cr is the working current, Il is the fundamental current, I h is the harmonic current to be filtered out.

[0016] Optionally, the rated capacity of the capacitor is expressed as:

[0017]

[0018] Among them, Q cr is the rated capacity of the capacitor, U cr is the rated voltage of the capacitor, I l is the fundamental current, I h is the harmonic current to be filtered out.

[0019] Optionally, the calculating, based on the rated capacity of the capacitor, a rated voltage of the capacitor that can filter out harmonics and has the smallest capacity includes:

[0020] Calculating a series reactance ratio between the capacitor and the reactance;

[0021] Calculating the fundamental voltage of the capacitor according to the series reactance ratio;

[0022] Substituting the fundamental voltage of the capacitor and the rated voltage of the capacitor into the rated capacity of the capacitor;

[0023] When the substitution is completed, the objective function is solved to obtain the rated voltage of the capacitor when it can filter out harmonics and the capacity is minimum; wherein the objective function indicates that the derivative of the rated capacity of the capacitor with respect to the rated voltage of the capacitor is 0.

[0024] Optionally, the series impedance ratio is expressed as:

[0025]

[0026] Wherein, τ is the series impedance, x L is the fundamental inductive reactance of the reactance, x C is the fundamental capacitive reactance of the reactance, U L is the fundamental voltage of the reactance, U C is the fundamental voltage of the capacitor.

[0027] Optionally, the fundamental voltage of the capacitor is expressed as:

[0028]

[0029] Wherein, τ is the series impedance, x L is the fundamental inductive reactance of the reactance, x C is the fundamental capacitive reactance of the reactance, U S is the system voltage of the single tuned filter, U Cis the fundamental voltage of the capacitor.

[0030] Optionally, the rated voltage of the capacitor is expressed as:

[0031]

[0032] in, is the rated voltage of the capacitor, U S is the system voltage of the single tuned filter, and τ is the series reactance ratio.

[0033] Optionally, the minimum capacity of the capacitor is expressed as:

[0034]

[0035] Among them, U cr,min is the minimum capacity of the capacitor, U S is the system voltage of the single tuned filter, I h is the harmonic current to be filtered out, and τ is the series reactance ratio.

[0036] A second aspect of the present invention provides a capacitance setting device for a filter, comprising:

[0037] A working current calculation module, used for calculating the working current flowing through the single tuned filter under the condition of harmonic injection into the single tuned filter; the single tuned filter includes a capacitor and a reactance;

[0038] A rated capacity calculation module, used to calculate the rated capacity of the capacitor according to the working current;

[0039] A rated voltage calculation module, used for calculating the rated voltage of the capacitor which can filter out harmonics and has the smallest capacity according to the rated capacity of the capacitor;

[0040] The minimum capacity calculation module is used to set the minimum capacity of the capacitor according to the rated voltage of the capacitor.

[0041] Optionally, the operating current is expressed as:

[0042]

[0043] Among them, I cr is the working current, I l is the fundamental current, I h is the harmonic current to be filtered out.

[0044] Optionally, the rated capacity of the capacitor is expressed as:

[0045]

[0046] Among them, Qcr is the rated capacity of the capacitor, U cr is the rated voltage of the capacitor, I l is the fundamental current, I h is the harmonic current to be filtered out.

[0047] Optionally, the rated voltage calculation module includes:

[0048] A series reactance ratio calculation module, used to calculate the series reactance ratio between the capacitor and the reactance;

[0049] A fundamental voltage calculation module, used for calculating the fundamental voltage of the capacitor according to the series reactance ratio;

[0050] A rated capacity conversion module, used for substituting the fundamental voltage of the capacitor and the rated voltage of the capacitor into the rated capacity of the capacitor;

[0051] The rated voltage solving module is used to solve the objective function when the substitution is completed to obtain the rated voltage of the capacitor when the capacitor can filter harmonics and the capacity is the smallest; wherein the objective function indicates that the derivative of the rated capacity of the capacitor with respect to the rated voltage of the capacitor is 0.

[0052] Optionally, the series impedance ratio is expressed as:

[0053]

[0054] Wherein, τ is the series impedance, x L is the fundamental inductive reactance of the reactance, x C is the fundamental capacitive reactance of the reactance, U L is the fundamental voltage of the reactance, U C is the fundamental voltage of the capacitor.

[0055] Optionally, the fundamental voltage of the capacitor is expressed as:

[0056]

[0057] Wherein, τ is the series impedance, x L is the fundamental inductive reactance of the reactance, x C is the fundamental capacitive reactance of the reactance, U S is the system voltage of the single tuned filter, U C is the fundamental voltage of the capacitor.

[0058] Optionally, the rated voltage of the capacitor is expressed as:

[0059]

[0060] in, is the rated voltage of the capacitor, US is the system voltage of the single tuned filter, and τ is the series reactance ratio.

[0061] Optionally, the minimum capacity of the capacitor is expressed as:

[0062]

[0063] Among them, U cr,min is the minimum capacity of the capacitor, U S is the system voltage of the single tuned filter, I h is the harmonic current to be filtered out, and τ is the series reactance ratio.

[0064] A third aspect of the present invention provides an electronic device, the electronic device comprising:

[0065] at least one processor; and

[0066] a memory communicatively connected to the at least one processor; wherein,

[0067] The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the capacitance setting method of the filter as described in the first aspect above.

[0068] A fourth aspect of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the capacitance setting method of the filter as described in the first aspect above is implemented.

[0069] A fifth aspect of the present invention provides a computer program product, the computer program product comprising a computer program, and when the computer program is executed by a processor, the capacitance setting method of the filter as described in the first aspect above is implemented.

[0070] In this embodiment, under the condition that harmonics are injected into a single tuned filter, the working current flowing through the single tuned filter is calculated; the single tuned filter includes a capacitor and a reactance; the rated capacity of the capacitor is calculated according to the working current; the rated voltage of the capacitor that can filter out harmonics and has the smallest capacity is calculated according to the rated capacity of the capacitor; and the minimum capacity of the capacitor is set according to the rated voltage of the capacitor. This embodiment calculates the minimum capacity of the capacitor while maintaining the harmonic filtering effect of the capacitor of the single tuned filter, which can reduce the cost of the capacitor, thereby reducing the cost of the single tuned filter, and when a large number of low single tuned filters are deployed in the distribution network, the cost can be reduced on a large scale.

[0071] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0073] Figure 1 This is a flow chart of a method for setting capacitance of a filter provided in Embodiment 1 of the present invention.

[0074] Figure 2 It is a structural schematic diagram of a single-tuned filter provided in Embodiment 1 of the present invention.

[0075] Figure 3 It is a structural schematic diagram of a capacitance setting device for a filter provided in Embodiment 2 of the present invention.

[0076] Figure 4 It is a structural schematic diagram of an electronic device provided in Embodiment 3 of the present invention. DETAILED DESCRIPTION

[0077] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0078] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present invention described herein can cover sequential implementations other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0079] Embodiment 1

[0080] See also Figure 1 , shows a flow chart of a method for setting the capacitance of a filter provided by Embodiment 1 of the present invention, the method can be executed by a capacitance setting device for a filter, the capacitance setting device for a filter can be implemented in the form of hardware and / or software, and the capacitance setting device for a filter can be configured in an electronic device. Figure 1 As shown, the method includes:

[0081] Step 101: Under the condition of harmonic injection into the single tuned filter, calculate the operating current flowing through the single tuned filter.

[0082] For the harmonic sources of the distribution network (especially the user side), according to their harmonic emission characteristics, for harmonics with higher orders, their harmonic pollution can be limited to a certain range by installing single-tuned filters.

[0083] like Figure 2 As shown, the single-tuned filter belongs to a passive power filter. The single-tuned filter includes a capacitor C, a reactance L and a resistor R. It is a resonant circuit composed of the capacitor C, the reactance L and the resistor R in series and parallel. For example, the capacitor C, the reactance L and the resistor R are connected in series, or the reactance L and the resistor R are connected in parallel and then in series with the capacitor C, etc. It can be mainly divided into a single-tuned filter, a double-tuned filter and a high-pass filter.

[0084] Generally, installing a single tuned filter near the harmonic source or at a public grid node can not only filter out harmonics but also play a role in reactive power compensation.

[0085] The principle of a single-tuned filter is to resonate at a specific frequency to form a low-impedance path, into which the harmonic current flows, thereby achieving the purpose of filtering out harmonics of a specific order.

[0086] In practical applications, the impedance of a single tuned filter can be expressed as:

[0087]

[0088] in, is the impedance of the single tuned filter, is the resistance of the single tuned filter, C is the capacitance of the single tuned filter, L is the reactance of the single tuned filter, h is the harmonic order, ω s is the fundamental frequency.

[0089] The principle of a single tuned filter is to have a series resonance at the characteristic frequency. At the resonance point:

[0090]

[0091] Where C is the capacitance of the single tuned filter, L is the reactance of the single tuned filter, h is the harmonic order, ω s is the fundamental frequency.

[0092] The filtering effect of a single tuned filter can be expressed using the quality factor:

[0093]

[0094] Where Q is the quality factor, R is the resistance of the single tuned filter, C is the capacitance of the single tuned filter, and L is the reactance of the single tuned filter.

[0095] In this embodiment, harmonics are injected into the single tuned filter (especially the capacitor). Under this condition, the operating current flowing through the single tuned filter (especially the capacitor) is calculated according to the main order harmonics.

[0096] Furthermore, the operating current flowing through the single tuned filter (especially the capacitor) is the root mean square value of the fundamental current and the main harmonic current.

[0097] Then, the operating current flowing through the single tuned filter (especially the capacitor) can be expressed as:

[0098]

[0099] Among them, I cr is the operating current flowing through the single tuned filter (especially the capacitor), I l is the fundamental current, I h is the harmonic current of the main harmonic order to be filtered out.

[0100] Step 102: Calculate the rated capacity of the capacitor according to the working current.

[0101] In this embodiment, the rated capacity of the capacitor may be expressed according to the operating current flowing through the single tuned filter (especially the capacitor).

[0102] In a specific implementation, the rated capacity of the capacitor is expressed as:

[0103]

[0104] Among them, Q cr is the rated capacity of the capacitor, U cr is the rated voltage of the capacitor, I l is the fundamental current, I h is the harmonic current of the main harmonic order to be filtered out.

[0105] Furthermore, the rated voltage of the capacitor takes into account the voltage-boosting effect of the reactance in the single-tuned filter and the superposition of harmonic voltages, and is usually higher than the system voltage of the single-tuned filter.

[0106] Step 103: Calculate the rated voltage of the capacitor that can filter out harmonics and has the smallest capacity based on the rated capacity of the capacitor.

[0107] In practical applications, the rated voltage at which the capacitor can filter out harmonics and when the capacity is minimum can be deduced based on the rated capacity of the capacitor.

[0108] In one embodiment of the present invention, step 103 may include the following steps:

[0109] Step 1031: Calculate the series reactance ratio between the capacitor and the reactance.

[0110] In this embodiment, the series reactance ratio between the capacitor and the reactance may be calculated, where the series reactance ratio refers to the percentage of the rated capacity of the series reactance to the rated capacity of the capacitor.

[0111] Exemplarily, the series impedance ratio is expressed as:

[0112]

[0113] Among them, τ is the series resistance, x L is the fundamental inductive reactance of the reactance, x C is the fundamental capacitive reactance of the reactance, U L is the fundamental voltage of the reactance, U C is the fundamental voltage of the capacitor.

[0114] Fundamental voltage of capacitor U C With the rated voltage U of the capacitor cr The difference between them is that the rated voltage U cr Taking into account the influence of harmonics, the fundamental voltage U C The influence of harmonics is not taken into account.

[0115] Step 1032: Calculate the fundamental voltage of the capacitor according to the series reactance ratio.

[0116] In this embodiment, the fundamental voltage of the capacitor can be derived according to the series reactance.

[0117] When the system voltage of a single tuned filter is set, based on the voltage division principle, the fundamental voltage of the capacitor is expressed as:

[0118]

[0119] Among them, τ is the series resistance, x L is the fundamental inductive reactance of the reactance, x C is the fundamental capacitive reactance of the reactance, U S is the system voltage of the single tuned filter, U C is the fundamental voltage of the capacitor.

[0120] Step 1033: Substitute the fundamental voltage of the capacitor and the rated voltage of the capacitor into the rated capacity of the capacitor.

[0121] In this embodiment, the rated capacity of the capacitor can be converted and expressed by substituting the fundamental voltage of the capacitor and the rated voltage of the capacitor into the rated capacity of the capacitor.

[0122] Considering:

[0123]

[0124] Among them, I l is the fundamental current, I h is the harmonic current of the main harmonic order to be filtered out, U C is the fundamental voltage of the capacitor, U cr is the rated voltage of the capacitor.

[0125] Then we have:

[0126]

[0127] Among them, τ is the series resistance, I h is the harmonic current of the main harmonic order to be filtered out, U cr is the rated voltage of the capacitor, U S is the system voltage of the single tuned filter, Q cr is the rated capacity of the capacitor.

[0128] Rated voltage of capacitor U cr Usually higher than the system voltage U of a single tuned filter S , for the 5th harmonic, generally U cr ≥1.042U S , for the 7th harmonic, generally U cr ≥1.02U S .

[0129] The rated voltage U of the capacitor cr It can be seen from the expression that the capacity of the filter capacitor can be determined based on the single harmonic current flowing through the single tuned filter and the rated voltage of the capacitor.

[0130] Step 1034: When the substitution is completed, the objective function is solved to obtain the rated voltage when the capacitor can filter out harmonics and has the smallest capacity.

[0131] The rated voltage U cr In the expression, due to the rated voltage U of the capacitor cr is to be determined, and the rated capacity of the capacitor Q cr With the rated voltage U cr Therefore, there is a minimum capacitance in theory.

[0132] In the specific implementation, the rated capacity Q of the capacitor can be cr With the rated voltage U of the capacitor cr Construct an objective function, wherein the objective function represents that the derivative of the rated capacity of the capacitor with respect to the rated voltage of the capacitor is 0, that is,

[0133] Then, when the capacitance of the capacitor is minimum, the rated voltage of the capacitor is expressed as:

[0134]

[0135] in, U is the rated voltage when the capacitor can filter out harmonics and has the smallest capacity. S is the system voltage of the single tuned filter, and τ is the series reactance ratio.

[0136] Step 104: Set the minimum capacity of the capacitor according to the rated voltage of the capacitor.

[0137] In this embodiment, the minimum capacity of the capacitor can be set by deduction according to the rated voltage of the capacitor.

[0138] In a specific implementation, the minimum capacity of the capacitor is expressed as:

[0139]

[0140] Among them, U cr,min is the minimum capacity of the capacitor, U S is the system voltage of the single tuned filter, I h is the harmonic current to be filtered out, and τ is the series reactance ratio.

[0141] From the expression of the minimum capacity of the capacitor, it can be seen that the capacity of the capacitor is determined by the single harmonic current flowing through the single-tuned filter and the system voltage of the single-tuned filter, and the rated voltage of the capacitor cannot be less than the rated voltage when the capacitor can filter out harmonics and the capacity is the smallest.

[0142] In this embodiment, under the condition that harmonics are injected into a single tuned filter, the working current flowing through the single tuned filter is calculated; the single tuned filter includes a capacitor and a reactance; the rated capacity of the capacitor is calculated according to the working current; the rated voltage of the capacitor that can filter out harmonics and has the smallest capacity is calculated according to the rated capacity of the capacitor; and the minimum capacity of the capacitor is set according to the rated voltage of the capacitor. This embodiment calculates the minimum capacity of the capacitor while maintaining the harmonic filtering effect of the capacitor of the single tuned filter, which can reduce the cost of the capacitor, thereby reducing the cost of the single tuned filter, and when a large number of low single tuned filters are deployed in the distribution network, the cost can be reduced on a large scale.

[0143] Embodiment 2

[0144] See also Figure 3 , shows a schematic diagram of the structure of a capacitance setting device for a filter provided by Embodiment 2 of the present invention. Figure 3 As shown, the device comprises:

[0145] The working current calculation module 301 is used to calculate the working current flowing through the single tuned filter under the condition that harmonics are injected into the single tuned filter; the single tuned filter includes a capacitor and a reactance;

[0146] A rated capacity calculation module 302, configured to calculate the rated capacity of the capacitor according to the operating current;

[0147] A rated voltage calculation module 303, used to calculate the rated voltage of the capacitor when the capacity is the smallest and can filter out harmonics according to the rated capacity of the capacitor;

[0148] The minimum capacity calculation module 304 is used to set the minimum capacity of the capacitor according to the rated voltage of the capacitor.

[0149] In one embodiment of the present invention, the operating current is expressed as:

[0150]

[0151] Among them, I cr is the working current, I l is the fundamental current, I h is the harmonic current to be filtered out.

[0152] In one embodiment of the present invention, the rated capacity of the capacitor is expressed as:

[0153]

[0154] Among them, Q cr is the rated capacity of the capacitor, U cr is the rated voltage of the capacitor, I l is the fundamental current, I h is the harmonic current to be filtered out.

[0155] In one embodiment of the present invention, the rated voltage calculation module 303 includes:

[0156] A series reactance ratio calculation module, used to calculate the series reactance ratio between the capacitor and the reactance;

[0157] A fundamental voltage calculation module, used for calculating the fundamental voltage of the capacitor according to the series reactance ratio;

[0158] A rated capacity conversion module, used for substituting the fundamental voltage of the capacitor and the rated voltage of the capacitor into the rated capacity of the capacitor;

[0159] The rated voltage solving module is used to solve the objective function when the substitution is completed to obtain the rated voltage of the capacitor when the capacitor can filter harmonics and the capacity is the smallest; wherein the objective function indicates that the derivative of the rated capacity of the capacitor with respect to the rated voltage of the capacitor is 0.

[0160] In one embodiment of the present invention, the series impedance ratio is expressed as:

[0161]

[0162] Wherein, τ is the series impedance, x L is the fundamental inductive reactance of the reactance, x C is the fundamental capacitive reactance of the reactance, U L is the fundamental voltage of the reactance, U C is the fundamental voltage of the capacitor.

[0163] In one embodiment of the present invention, the fundamental voltage of the capacitor is expressed as:

[0164]

[0165] Wherein, τ is the series impedance, x L is the fundamental inductive reactance of the reactance, x C is the fundamental capacitive reactance of the reactance, U S is the system voltage of the single tuned filter, U C is the fundamental voltage of the capacitor.

[0166] In one embodiment of the present invention, the rated voltage of the capacitor is expressed as:

[0167]

[0168] in, is the rated voltage of the capacitor, U S is the system voltage of the single tuned filter, and τ is the series reactance ratio.

[0169] In one embodiment of the present invention, the minimum capacity of the capacitor is expressed as:

[0170]

[0171] Among them, U cr,min is the minimum capacity of the capacitor, U S is the system voltage of the single tuned filter, I h is the harmonic current to be filtered out, and τ is the series reactance ratio.

[0172] The capacitance setting device for a filter provided in an embodiment of the present invention can execute the capacitance setting method for a filter provided in any embodiment of the present invention, and has corresponding functional modules and beneficial effects for executing the capacitance setting method for a filter.

[0173] Embodiment 3

[0174] See also Figure 4 , showing a schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workbenches, personal digital assistants, blade servers, mainframe computers, and other suitable computers. The electronic device may also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices (such as helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present invention described and / or required herein.

[0175] like Figure 4 As shown, the electronic device 10 includes at least one processor 11, and a memory connected to the at least one processor 11, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc., wherein the memory stores a computer program that can be executed by at least one processor, and the processor 11 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 12 or the computer program loaded from the storage unit 18 to the random access memory (RAM) 13. In the RAM 13, various programs and data required for the operation of the electronic device 10 can also be stored. The processor 11, the ROM 12, and the RAM 13 are connected to each other through a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0176] A number of components in the electronic device 10 are connected to the I / O interface 15, including: an input unit 16, such as a keyboard, a mouse, etc.; an output unit 17, such as various types of displays, speakers, etc.; a storage unit 18, such as a disk, an optical disk, etc.; and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 19 allows the electronic device 10 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0177] The processor 11 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any appropriate processor, controller, microcontroller, etc. The processor 11 performs the various methods and processes described above, such as the capacitance setting method of the filter.

[0178] In some embodiments, the capacitance setting method of the filter can be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as a storage unit 18. In some embodiments, part or all of the computer program can be loaded and / or installed on the electronic device 10 via the ROM 12 and / or the communication unit 19. When the computer program is loaded into the RAM 13 and executed by the processor 11, one or more steps of the capacitance setting method of the filter described above can be performed. Alternatively, in other embodiments, the processor 11 can be configured to execute the capacitance setting method of the filter by any other appropriate means (e.g., by means of firmware).

[0179] Various implementations 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 chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0180] Computer programs for implementing 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, so that when the computer program is executed by the processor, the functions / operations specified in the flow chart and / or block diagram are implemented. The computer program may be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0181] In the context of the present invention, a computer-readable storage medium may be a tangible medium that may contain or store a computer program for use by or in combination with an instruction execution system, device or equipment. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or equipment, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0182] To provide interaction with a user, the systems and techniques described herein may 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 a pointing device (e.g., a mouse or trackball) through which the user can provide input to the electronic device. Other types of devices may also be used to provide interaction with the user; for example, the feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form (including acoustic input, voice input, or tactile input).

[0183] The systems and techniques described herein may be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0184] A computing system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The client and server relationship is generated by computer programs running on the corresponding computers and having a client-server relationship with each other. The server may be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system to solve the defects of difficult management and weak business scalability in traditional physical hosts and VPS services.

[0185] Embodiment 4

[0186] An embodiment of the present invention further provides a computer program product, which includes a computer program. When the computer program is executed by a processor, the method for setting the capacitance of the filter provided in any embodiment of the present invention is implemented.

[0187] In the process of implementation, the computer program product can be written in one or more programming languages ​​or a combination thereof to perform the computer program code of the present invention, including object-oriented programming languages, such as Java, Smalltalk, C++, and conventional procedural programming languages, such as "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computer (for example, using an Internet service provider to connect through the Internet).

[0188] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0189] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for setting the capacitance of a filter, characterized in that: include: Under the condition of harmonic injection into a single tuned filter, calculating the operating current flowing through the single tuned filter; the single tuned filter includes a capacitor and a reactance; Calculating the rated capacity of the capacitor according to the working current; Calculate the rated voltage of the capacitor when the capacitor can filter out harmonics and has the smallest capacity according to the rated capacity of the capacitor; The minimum capacity of the capacitor is set according to the rated voltage of the capacitor.

2. The method according to claim 1, characterized in that The working current is expressed as: Among them, I cr is the working current, I l is the fundamental current, I h is the harmonic current to be filtered out.

3. The method according to claim 2, characterized in that The rated capacity of the capacitor is expressed as: Among them, Q cr is the rated capacity of the capacitor, U cr is the rated voltage of the capacitor, I l is the fundamental current, I h is the harmonic current to be filtered out.

4. The method according to any one of claims 1 to 3, characterized in that The step of calculating the rated voltage of the capacitor that can filter out harmonics and has the smallest capacity based on the rated capacity of the capacitor includes: Calculating a series reactance ratio between the capacitor and the reactance; Calculating the fundamental voltage of the capacitor according to the series reactance ratio; Substituting the fundamental voltage of the capacitor and the rated voltage of the capacitor into the rated capacity of the capacitor; When the substitution is completed, the objective function is solved to obtain the rated voltage of the capacitor when it can filter out harmonics and the capacity is minimum; wherein the objective function indicates that the derivative of the rated capacity of the capacitor with respect to the rated voltage of the capacitor is 0.

5. The method according to claim 4, characterized in that The series impedance ratio is expressed as: Wherein, τ is the series impedance, x L is the fundamental inductive reactance of the reactance, x C is the fundamental capacitive reactance of the reactance, U L is the fundamental voltage of the reactance, U C is the fundamental voltage of the capacitor.

6. The method according to claim 5, characterized in that The fundamental voltage of the capacitor is expressed as: Wherein, τ is the series impedance, x L is the fundamental inductive reactance of the reactance, x C is the fundamental capacitive reactance of the reactance, U S is the system voltage of the single tuned filter, U C is the fundamental voltage of the capacitor.

7. The method according to claim 6, characterized in that The rated voltage of the capacitor is expressed as: in, is the rated voltage of the capacitor, U S is the system voltage of the single tuned filter, and τ is the series reactance ratio.

8. The method according to claim 7, characterized in that The minimum capacity of the capacitor is expressed as: Among them, U cr,min is the minimum capacity of the capacitor, U S is the system voltage of the single tuned filter, I h is the harmonic current to be filtered out, and τ is the series reactance ratio.

9. An electronic device, characterized in that: The electronic device comprises: at least one processor; and a memory communicatively connected to the at least one processor; wherein, The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can perform the capacitance setting method for the filter according to any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the capacitance setting method of the filter according to any one of claims 1 to 8 is implemented.

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