Harmonic compensation method and device based on static synchronous compensator, equipment and medium

Abstract

The embodiment of the application discloses a harmonic compensation method and device based on a static synchronous compensator, equipment and a medium, and the method comprises the following steps: a state space model of the static synchronous compensator containing disturbance of a high-voltage direct-current transmission system is constructed; a sliding mode disturbance observer is used to observe and estimate disturbance items in the state space model of the static synchronous compensator in real time, and the disturbance items of the high-voltage direct-current transmission system are determined; and the compensation voltage of a specified harmonic is introduced into the disturbance items of the high-voltage direct-current transmission system based on the integral of the transfer function of a resonance controller, so that the voltage compensation of the high-voltage direct-current transmission system to the specified harmonic disturbance is realized. The quasi-resonance is introduced into the sliding mode disturbance observer, the control of the static synchronous compensator is optimized, the specified harmonic of the high-voltage direct-current transmission system is estimated and compensated in real time, the propagation of the harmonic is blocked from the source, the harmonic voltage is effectively inhibited, and the risk of subsequent commutation failure in the fault recovery process of the high-voltage direct-current transmission system is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power systems, and particularly relates to a harmonic compensation method and device based on a static synchronous compensator, equipment and a medium. BACKGROUND

[0002] The AC system fault on the inverter side of a high-voltage direct current transmission system is prone to cause a sharp increase in harmonics, and if the harmonics are not compensated during the fault recovery process, voltage distortion will be caused, which will exacerbate the risk of commutation failure, and low-order harmonics have a greater impact on the commutation process of the direct current system.

[0003] At present, most of the existing methods for compensating harmonics are to directly suppress harmonics by modifying the control of the high-voltage direct current transmission system, which is a huge amount of engineering and has poor effect. Therefore, there is currently no effective method to suppress harmonics. SUMMARY

[0004] Therefore, it is necessary to propose a harmonic compensation method and device based on a static synchronous compensator, equipment and a medium to effectively suppress harmonics of a high-voltage direct current transmission system and ensure safe operation of the high-voltage direct current transmission system.

[0005] To achieve the above-mentioned purpose, the first aspect of the present application provides a harmonic compensation method based on a static synchronous compensator, which comprises:

[0006] Based on the circuit structure and parameters of the static synchronous compensator connected to the high-voltage direct current transmission system, a state space model of the static synchronous compensator containing disturbances of the high-voltage direct current transmission system is constructed;

[0007] A sliding mode disturbance observer is introduced into the current inner loop of the static synchronous compensator to observe and estimate the disturbance term in the state space model of the static synchronous compensator in real time, and the disturbance term of the high-voltage direct current transmission system is determined;

[0008] The transfer function of the resonant controller is integrated, and the compensation voltage of the specified harmonic obtained by integration is introduced into the disturbance term of the high-voltage direct current transmission system to perform voltage compensation of the specified harmonic disturbance of the high-voltage direct current transmission system.

[0009] Further, the sliding mode disturbance observer is designed as follows:

[0010]

[0011] In the formula: and are the d-axis and q-axis components of the observed current estimated by the sliding mode disturbance observer, , respectively an equivalent resistance and an equivalent inductance of the static synchronous compensator ac side to the point of common coupling, , respectively d, q axis components of three phase voltages of the point of common coupling bus, , respectively d, q axis components of three phase voltages of the static synchronous compensator ac side, is an angular frequency of the high voltage direct current transmission system, , are d, q axis components of the high voltage direct current transmission system disturbance term estimated by the sliding mode disturbance observer, , is a preset sliding mode gain coefficient; , is a preset error gain coefficient; , is a boundary layer thickness of the saturation function, is a saturation function, and are d, q axis components of current error.

[0012] Further, the transfer function of the resonance controller is integrated, and a compensation voltage of a specified harmonic is introduced into a disturbance term of the high voltage direct current transmission system to perform voltage compensation of the specified harmonic disturbance on the high voltage direct current transmission system, and specifically includes:

[0013] The transfer function of the resonance controller is converted into a state space form to obtain a quasi-resonance term state space equation;

[0014] A specified resonance integral is performed according to the quasi-resonance term state space equation to obtain a total resonance compensation output by the resonance controller;

[0015] The total resonance compensation output by the resonance controller is introduced into the disturbance term of the high voltage direct current transmission system to perform voltage compensation of the specified harmonic disturbance on the high voltage direct current transmission system.

[0016] Further, the total resonance compensation output by the resonance controller is introduced into the disturbance term of the high voltage direct current transmission system to perform voltage compensation of the specified harmonic disturbance on the high voltage direct current transmission system, and specifically includes:

[0017] The total resonance compensation output by the resonance controller is decomposed to obtain d-axis resonance output and q-axis resonance output of the resonance controller in a d-q synchronous rotating coordinate system;

[0018] The d-axis resonance output and the q-axis resonance output are combined with d, q axis components of the high voltage direct current transmission system disturbance term to obtain compensation harmonic voltages of d-axis and q-axis specified harmonics.

[0019] The compensation harmonic voltage based on the d-axis and q-axis specified harmonic is used to compensate the voltage of the high-voltage direct-current power transmission system disturbed by the specified harmonic.

[0020] Further, the compensation harmonic voltage based on the d-axis and q-axis specified harmonic is used to compensate the voltage of the high-voltage direct-current power transmission system disturbed by the specified harmonic, and specifically includes:

[0021] An actual voltage output after PI controller voltage compensation in the current inner loop of the static synchronous compensator is obtained.

[0022] Difference calculation is performed according to the actual voltage and the compensation harmonic voltage based on the d-axis and q-axis specified harmonic, to obtain an output voltage after specified harmonic compensation, so as to compensate the voltage of the high-voltage direct-current power transmission system disturbed by the specified harmonic based on the output voltage.

[0023] Further, the compensation harmonic voltage based on the d-axis and q-axis specified harmonic is calculated by the following formula:

[0024]

[0025] In the formula, and are the compensation harmonic voltages of the d-axis and q-axis specified harmonic respectively, is a specified harmonic set, is a specified harmonic, is a resonance gain coefficient of the hth harmonic, is a Laplace variable, is a fundamental frequency, and are harmonic disturbance values of the resonance d-axis and q-axis of the hth harmonic.

[0026] Further, the quasi-resonance term state space equation is represented by the following formula:

[0027]

[0028] In the formula, is an integral state variable of the hth resonance controller, is a differential state variable of the hth resonance controller, and h is a specified harmonic, is a fundamental frequency, is a damping ratio, is a cut-off bandwidth, is a resonance gain coefficient of the hth harmonic, is a time domain representation of an input signal.

[0029] To achieve the above object, the second aspect of the present application provides a harmonic compensation device based on a static synchronous compensator, the device comprising:

[0030] a model construction unit configured to construct a state space model of the static synchronous compensator containing disturbance of the high-voltage direct current power transmission system based on circuit structure and parameters of the static synchronous compensator connected to the high-voltage direct current power transmission system;

[0031] a disturbance estimation unit configured to introduce a sliding mode disturbance observer into a current inner loop of the static synchronous compensator, to observe and estimate a disturbance term in the state space model of the static synchronous compensator in real time, and to determine the disturbance term of the high-voltage direct current power transmission system;

[0032] a voltage compensation unit configured to perform integration based on a transfer function of a resonant controller, to introduce a compensation voltage of a specified harmonic obtained by the integration into the disturbance term of the high-voltage direct current power transmission system, and to perform voltage compensation of the high-voltage direct current power transmission system from the specified harmonic disturbance.

[0033] To achieve the above object, the third aspect of the present application provides a computer readable storage medium storing a computer program, the computer program being executed by a processor to make the processor perform the steps of the method according to the first aspect.

[0034] To achieve the above object, the fourth aspect of the present application provides a computer device comprising a memory and a processor, the memory storing a computer program, the computer program being executed by the processor to make the processor perform the steps of the method according to the first aspect.

[0035] The present application has the following advantages:

[0036] The present application provides a harmonic compensation method based on a static synchronous compensator, the method comprising: constructing a state space model of the static synchronous compensator containing disturbance of a high-voltage direct current power transmission system based on circuit structure and parameters of the static synchronous compensator connected to the high-voltage direct current power transmission system; introducing a sliding mode disturbance observer into a current inner loop of the static synchronous compensator, observing and estimating a disturbance term in the state space model of the static synchronous compensator in real time, and determining the disturbance term of the high-voltage direct current power transmission system; performing integration based on a transfer function of a resonant controller, introducing a compensation voltage of a specified harmonic obtained by the integration into the disturbance term of the high-voltage direct current power transmission system, and performing voltage compensation of the high-voltage direct current power transmission system from the specified harmonic disturbance. The present application introduces quasi-resonance into the sliding mode disturbance observer, optimizes control of the static synchronous compensator, estimates and compensates the specified harmonic of the high-voltage direct current power transmission system in real time, blocks propagation of the harmonic from the source, effectively suppresses the harmonic voltage, and reduces the risk of subsequent commutation failure in the fault recovery process of the high-voltage direct current power transmission system. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description only constitute some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0038] Wherein:

[0039] Figure 1 A flowchart of the harmonic compensation method based on the static synchronous compensator according to the embodiment of the present application is shown in the figure.

[0040] Figure 2 A time-domain model of the STATCOM in the embodiment of the present application is shown in the figure.

[0041] Figure 3 A specific sub-harmonic compensation control strategy diagram of the QRSMDO in the embodiment of the present application is shown in the figure.

[0042] Figure 4 A structure block diagram of the harmonic compensation device based on the static synchronous compensator in the embodiment of the present application is shown in the figure.

[0043] Figure 5 An internal structure diagram of the computer device in the embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments only constitute some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort fall within the scope of protection of the present application.

[0045] In order to improve the harmonic suppression effect of the high-voltage direct-current transmission system, the static synchronous compensator (STATCOM) connected to the inverter side of the high-voltage direct-current transmission system is selected for optimization. The STATCOM under traditional control has poor harmonic suppression effect and cannot accurately compensate for the harmonics in the fault recovery process.

[0046] Based on this, the harmonic compensation method based on the static synchronous compensator is proposed in the embodiment of the present application to realize accurate compensation for the harmonics in the fault recovery process. For reference, Figure 1 , Figure 1 A flowchart of the harmonic compensation method based on the static synchronous compensator according to the embodiment of the present application is shown in the figure. The method comprises:

[0047] In step 110, a state space model of the STATCOM disturbed by the high-voltage direct-current power transmission system is constructed based on the circuit structure and parameters of the STATCOM connected to the high-voltage direct-current power transmission system.

[0048] In the embodiment of the present application, first, the time-domain model of the STATCOM connected to the high-voltage direct-current power transmission system is determined, which can be referred to as Figure 2 , Figure 2 the time-domain model of the STATCOM in the embodiment of the present application. Wherein, , are the equivalent resistance and the equivalent inductance from the AC side of the STATCOM to the grid point, , , are the three-phase voltages of the bus of the grid point, , , are the three-phase reactive compensation currents of the STATCOM flowing to the grid point, , , are the three-phase voltages of the AC side of the STATCOM, is the DC side voltage of the STATCOM.

[0049] Secondly, the state space model of the STATCOM can be established according to the time-domain model of the STATCOM, and the state space equation of the STATCOM is obtained through the Park transformation and ignoring the zero component:

[0050]

[0051] In the formula, wherein: , are the d-axis and q-axis components of the three-phase reactive compensation currents of the STATCOM flowing to the grid point, , are the equivalent resistance and the equivalent inductance from the AC side of the STATCOM to the grid point, , are the d-axis and q-axis components of the three-phase voltages of the bus of the grid point, , are the d-axis and q-axis components of the three-phase voltages of the AC side of the STATCOM, is the angular frequency of the high-voltage direct-current power transmission system, and C is the DC side capacitance of the STATCOM, is the DC side voltage of the STATCOM.

[0052] In an embodiment, the state space model of the STATCOM disturbed by the high-voltage direct-current power transmission system is:

[0053]

[0054] wherein: , are the d, q-axis components of the three-phase reactive compensation current of the static synchronous compensator flowing to the point of common coupling, , are the equivalent resistance and equivalent inductance from the AC side of the static synchronous compensator to the point of common coupling, , are the d, q-axis components of the three-phase voltage of the bus at the point of common coupling, , are the d, q-axis components of the three-phase voltage at the AC side of the static synchronous compensator, is the angular frequency of the high voltage direct current transmission system, and C is the DC side capacitance of the static synchronous compensator, are the d, q-axis components of the total disturbance term of the high voltage direct current transmission system.

[0055] In the embodiment, the total disturbance term includes unmodeled disturbances and harmonic disturbance terms generated by faults of the high voltage direct current transmission system. Since the harmonics causing subsequent commutation failures during the fault recovery process are mainly low-order harmonics, the 15th harmonic is considered in the embodiment.

[0056] Step 120: introducing a sliding mode disturbance observer into the current inner loop of the static synchronous compensator to observe and estimate the disturbance term in the state space model of the static synchronous compensator in real time, and determine the disturbance term of the high voltage direct current transmission system.

[0057] The sliding mode disturbance observer (SMDO) is used to estimate and compensate disturbances in the system in real time to improve the performance and anti-interference ability of the control system. The sliding mode disturbance observer is based on the sliding mode control (SMC) theory. By constructing a sliding surface, the system state slides on the sliding surface, so as to realize the estimation of the system state and the observation of the disturbance. The SMDO estimates the disturbances in the system, such as load changes and parameter uncertainties, in real time by observing the output and state of the system. These estimated values can be used as a feedforward signal to compensate the output of the controller, thereby improving the anti-interference performance of the system.

[0058] Step 130: integrating the transfer function of the resonant controller to introduce the compensation voltage of the specified harmonic obtained by integration into the disturbance term of the high voltage direct current transmission system to perform voltage compensation for the specified harmonic disturbance of the high voltage direct current transmission system.

[0059] In the embodiment of the present application, a resonance integral term is introduced into the sliding mode term of the sliding mode disturbance observer to improve the sliding mode disturbance observer, so that the improved quasi-resonance sliding mode disturbance observer (QRSMDO) can extract a specific harmonic to eliminate the harmonic disturbance of the specific harmonic by a compensation voltage of the specific harmonic, to achieve accurate compensation of the harmonic in the fault recovery process, achieve better effect of suppressing harmonic voltage, and reduce the risk of subsequent commutation failure in the fault recovery process of the high-voltage direct current transmission system.

[0060] In an embodiment of the present application, the sliding mode disturbance observer is designed as follows:

[0061]

[0062] In the formula: And are the d-axis and q-axis components of the observed current estimated by the sliding mode disturbance observer, , are the equivalent resistance and equivalent inductance from the alternating current side of the static synchronous compensator to the grid point, , are the d-axis and q-axis components of the three-phase voltage of the grid point bus, , are the d-axis and q-axis components of the three-phase voltage of the alternating current side of the static synchronous compensator, is the angular frequency of the high-voltage direct current transmission system, , are the d-axis and q-axis components of the disturbance term of the high-voltage direct current transmission system estimated by the sliding mode disturbance observer, , is a preset sliding mode gain coefficient, , is used to adjust the convergence speed of the sliding mode disturbance observer; , is a preset error gain coefficient; , is the boundary layer thickness of the saturation function, is the saturation function, And are the d-axis and q-axis components of the current error.

[0063] In the embodiment, the current error is:

[0064]

[0065] In the formula, , are the d-axis and q-axis components of the observed current estimated by the sliding mode disturbance observer, , The d and q axis components of the three-phase reactive compensation current flowing from the static synchronous compensator to the grid point.

[0066] In an embodiment of the present application, a quasi-resonant term is introduced into the sliding mode term of the sliding mode disturbance observer, so that the sliding mode disturbance observer can separate the specified harmonic disturbance from the total disturbance. A quasi-resonant sliding mode disturbance observer (QRSMDO) is designed in the current inner loop of the STATCOM, so as to output a compensation voltage of the specified harmonic through the QRSMDO. Based on this, step 130 integrates the compensation voltage of the specified harmonic obtained based on the transfer function of the resonant controller, and introduces the compensation voltage of the specified harmonic into the disturbance term of the high-voltage direct-current power transmission system, so as to perform voltage compensation of the high-voltage direct-current power transmission system on the specified harmonic disturbance. Specifically, the step includes:

[0067] Step 131 converts the transfer function of the resonant controller into a state space form to obtain a quasi-resonant term state space equation.

[0068] In the embodiment, the resonant integral term is introduced into the sliding mode term of the sliding mode disturbance observer to improve the sliding mode disturbance observer, so that the sliding mode disturbance observer can extract a specific harmonic, as shown in the following formula:

[0069]

[0070] In the formula, is a specified harmonic set, is a specified harmonic, is a resonant gain coefficient of the hth harmonic, is a damping ratio, is a cutoff bandwidth, h is a harmonic order, and s is a Laplace variable, is a fundamental frequency.

[0071] In an embodiment, considering that low-order harmonics have a greater impact on the system after a fault, the 15th harmonic is considered here, that is, the specified harmonic set is .

[0072] In the embodiment, the transfer function of each resonant controller is converted into a state space form for the convenience of digital implementation.

[0073] First, for each harmonic order h, two state variables are defined:

[0074] : the first state variable of the resonator, the integral state variable of the hth resonant controller;

[0075] : the second state variable of the resonator, the differential state variable of the hth resonant controller.

[0076] The transfer function of the resonant controller is:

[0077]

[0078] wherein, is the transfer function of the hth harmonic resonant controller, is the Laplace transform of is the Laplace transform of the input signal is the time domain representation of the input signal.

[0079] The above transfer function is equivalent to:

[0080]

[0081] Let , be the Laplace transform of , i.e. the integral of , then:

[0082]

[0083] After inverse Laplace transform, the state space equation of the quasi-resonant term is:

[0084]

[0085] wherein, is the integral state variable of the hth harmonic resonant controller is the inverse Laplace transform of is the differential state variable of the hth harmonic resonant controller is the inverse Laplace transform of is the derivative of is the fundamental frequency, is the damping ratio, is the cut-off bandwidth, is the resonance gain coefficient, is the time domain representation of the input signal.

[0086] Step 132, according to the quasi-resonant term state space equation, the integral of the specified harmonic resonance is obtained, and the total resonance compensation of the resonant controller output is obtained.

[0087] In this embodiment, the hth harmonic output of the resonant controller is defined as: .

[0088] The outputs of all the arrays in the specified harmonic are added to obtain the total resonance compensation output:

[0089] ​​

[0090] wherein, is the total resonance compensation output by the resonance controller, is the specified harmonic set, and h is the specified harmonic.

[0091] Step 133, introducing the total resonance compensation output by the resonance controller into the disturbance term of the high-voltage direct-current power transmission system to perform voltage compensation of the high-voltage direct-current power transmission system for the specified harmonic disturbance.

[0092] In this embodiment, the total resonance compensation output by the resonance controller is combined with the sliding mode disturbance observer to perform voltage compensation of the high-voltage direct-current power transmission system for the specified harmonic disturbance.

[0093] In an embodiment, Step 133, introducing the total resonance compensation output by the resonance controller into the disturbance term of the high-voltage direct-current power transmission system to perform voltage compensation of the high-voltage direct-current power transmission system for the specified harmonic disturbance, specifically comprises:

[0094] Step 1331, decomposing the total resonance compensation output by the resonance controller to obtain the d-axis resonance output and the q-axis resonance output of the resonance controller in the d-q synchronous rotating coordinate system; combining the d-axis resonance output and the q-axis resonance output with the d-axis and q-axis components of the disturbance term of the high-voltage direct-current power transmission system to obtain the compensation harmonic voltage of the d-axis and q-axis specified harmonic.

[0095] In this embodiment, the above resonance compensation term is combined with the basic sliding mode disturbance observer to complete the dual-mode harmonic tracking QRSMDO structure as follows:

[0096] The QRSMDO design of the d-axis is as follows:

[0097]

[0098] wherein, is the total output of the d-axis resonance controller.

[0099] Considering the error dynamics, the d-axis current error After derivation and simplification, we get:

[0100] The theoretical estimation formula of the d-axis harmonic disturbance is:

[0101]

[0102] wherein, is the d-axis harmonic disturbance value estimated by the QRSMDO.

[0103] Since the proportional coefficient will be absorbed by the gain of the subsequent controller, the d-axis harmonic disturbance value is simplified in engineering implementation as:

[0104]

[0105] Similarly, the QRSMDO design of the q-axis is as follows:

[0106]

[0107] In the formula, is the total output of the d-axis resonant controller.

[0108] The hth q-axis harmonic disturbance value is:

[0109]

[0110] In the formula, is the hth q-axis harmonic disturbance value estimated by the QRSMDO.

[0111] In an embodiment, the compensation harmonic voltages of the d-axis and q-axis specified harmonics are calculated by the following formula:

[0112]

[0113] In the formula, and are the compensation harmonic voltages of the d-axis and q-axis specified harmonics respectively, is the specified harmonic combination, is the specified harmonic, is the resonant gain coefficient of the hth harmonic, is the Laplace variable, is the fundamental frequency, and are the harmonic disturbance values of the d-axis and q-axis of the hth resonance.

[0114] Step 1332, based on the compensation harmonic voltages of the d-axis and q-axis specified harmonics, the high-voltage direct-current power transmission system is subjected to voltage compensation of specified harmonic disturbance.

[0115] Reference can be made to Figure 3 , Figure 3 is the QRSMDO specified harmonic compensation control strategy diagram in the embodiment of the application, the implementation of the QRSMDO in the STATCOM current inner loop is shown in the figure, voltage and current data are collected from the power grid and the STATCOM main circuit; the collected three-phase data are converted to the synchronous rotating coordinate system, the control algorithm is simplified; PI control and QRSMDIO control strategy are applied, the required control signal is calculated; the actual value is compared with the reference value, and the control signal is continuously optimized through feedback adjustment. The QRSMDO estimates and compensates the harmonics caused by the fault of the high-voltage direct-current power transmission system in real time, and blocks the propagation of harmonics from the source.

[0116] In an embodiment, Step 1332, the compensation harmonic voltage of the specified sub-harmonic based on the d-axis and the q-axis specifies the voltage compensation of the high-voltage direct current transmission system for the specified sub-harmonic disturbance, specifically comprising:

[0117] The actual voltage output after the PI controller voltage compensation in the current inner loop of the static synchronous compensator is obtained; the output voltage after the specified sub-harmonic compensation is obtained by difference calculation according to the actual voltage and the compensation harmonic voltage of the specified sub-harmonic on the d-axis and the q-axis, so as to compensate the voltage of the high-voltage direct current transmission system for the specified sub-harmonic disturbance based on the output voltage.

[0118] Specifically, the voltage after the QRSMDO voltage compensation is as follows:

[0119]

[0120] In the formula, , are the d-axis and q-axis components of the actual voltage output after the PI controller voltage compensation in the current inner loop of the static synchronous compensator, and are the compensation harmonic voltages of the specified sub-harmonic on the d-axis and the q-axis, , are the output voltages after the QRSMDO harmonic voltage compensation. The voltage compensation of the high-voltage direct current transmission system for the specified sub-harmonic disturbance is performed through the output voltage after the QRSMDO harmonic voltage compensation, so as to realize accurate compensation of the harmonic in the fault recovery process, achieve better harmonic voltage suppression effect, and reduce the risk of subsequent commutation failure in the fault recovery process of the high-voltage direct current transmission system.

[0121] In the embodiment of the application, the harmonic disturbance extracted by the QRSMDO , The compensation voltage is generated by the quasi-resonant controller, which is opposite in phase to the grid harmonic voltage, realizes offset, and in the fault recovery process of the inverter side of the high-voltage direct current transmission system, the harmonic voltage compensation of the STATCOM is obtained, so that the voltage no longer distorts, effectively reducing the risk of subsequent commutation failure in the fault recovery process.

[0122] In an embodiment of the application, a harmonic compensation device based on a static synchronous compensator is provided, which can be referred to Figure 4 , Figure 4 is the structure block diagram of the harmonic compensation device based on the static synchronous compensator in the embodiment of the application, and the device comprises:

[0123] The model construction unit 401 is configured to construct a state space model of the static synchronous compensator containing the disturbance of the high-voltage direct current transmission system based on the circuit structure and parameters of the static synchronous compensator accessed to the high-voltage direct current transmission system.

[0124] The disturbance estimation unit 402 is used to introduce a sliding mode disturbance observer into the current inner loop of the static synchronous compensator to perform real-time observation and estimation of the disturbance terms in the state space model of the static synchronous compensator, and to determine the disturbance terms of the high voltage DC transmission system.

[0125] The voltage compensation unit 403 is used to perform integration based on the transfer function of the resonant controller, and introduce the compensation voltage of the specified harmonic obtained by integration into the disturbance term of the high voltage direct current transmission system, so as to perform voltage compensation for the specified harmonic disturbance of the high voltage direct current transmission system.

[0126] The harmonic compensation device based on the static synchronous compensator in this embodiment of the invention introduces quasi-resonance into the sliding mode disturbance observer, thereby optimizing the control of the static synchronous compensator, realizing real-time estimation and compensation of the specified harmonics of the high voltage direct current transmission system, blocking the propagation of harmonics from the source, effectively suppressing harmonic voltage, and reducing the risk of subsequent commutation failure during the fault recovery process of the high voltage direct current transmission system.

[0127] Figure 5 An internal structural diagram of a computer device according to one embodiment of the present invention is shown. This computer device can specifically be a terminal or a system. Figure 5 As shown, the computer device includes a processor, memory, and network interface connected via a system bus. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system and may also store a computer program. When executed by the processor, this computer program causes the processor to perform the steps in the above-described method embodiments. The internal memory may also store a computer program, which, when executed by the processor, causes the processor to perform the steps in the above-described method embodiments. Those skilled in the art will understand that... Figure 5 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0128] In one embodiment, a computer device is provided, including a memory and a processor, the memory storing a computer program that, when executed by the processor, causes the processor to perform the steps in the above method embodiments.

[0129] In one embodiment, a computer-readable storage medium is provided storing a computer program that, when executed by a processor, causes the processor to perform the steps in the above method embodiments.

[0130] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program. The program can be stored in a non-volatile computer readable storage medium, and when the program is executed, the processes of the above-mentioned embodiment methods can be included. Any reference to memory, storage, database or other medium used in the embodiments provided in the present application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration but not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0131] Any combination of the technical features of the above embodiments can be made. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combination of the technical features does not exist, it should be considered as the scope of the present application.

[0132] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A harmonic compensation method based on a static synchronous compensator, characterized in that, The method includes: Based on the circuit structure and parameters of the static synchronous compensator connected to the high-voltage direct current transmission system, a state-space model of the static synchronous compensator containing the disturbance of the high-voltage direct current transmission system is constructed. A sliding mode disturbance observer is introduced into the inner current loop of the static synchronous compensator to perform real-time observation and estimation of the disturbance terms in the state space model of the static synchronous compensator, thereby determining the disturbance terms of the high voltage direct current transmission system. The transfer function of the resonant controller is integrated, and the compensation voltage of the specified harmonic obtained by integration is introduced into the disturbance term of the high voltage direct current transmission system to compensate for the voltage disturbance of the specified harmonic in the high voltage direct current transmission system. Specifically, the transfer function based on the resonant controller is integrated, and the compensation voltage for the specified harmonic is introduced into the disturbance term of the high-voltage direct current transmission system to compensate for the specified harmonic disturbance in the high-voltage direct current transmission system. This includes: The transfer function of the resonant controller is converted into a state-space form to obtain the quasi-resonant term state-space equation; The total resonance compensation output by the resonance controller is obtained by performing a specified resonance integral based on the state-space equation of the quasi-resonance term. The total resonance compensation output by the resonant controller is introduced into the disturbance term of the high voltage direct current transmission system to compensate for the voltage of the specified harmonic disturbance of the high voltage direct current transmission system. Specifically, the step of incorporating the total resonance compensation output by the resonance controller into the disturbance term of the high-voltage direct current transmission system to perform voltage compensation for specified harmonic disturbances in the high-voltage direct current transmission system includes: The total resonance compensation output of the resonance controller is decomposed to obtain the d-axis resonance output and q-axis resonance output of the resonance controller in the dq synchronous rotating coordinate system; The d-axis resonant output and q-axis resonant output are combined with the d-axis and q-axis components of the disturbance term of the high-voltage direct current transmission system to obtain the compensation harmonic voltage for the specified harmonics on the d-axis and q-axis. The voltage compensation for specified harmonic disturbances in the high voltage direct current transmission system is performed based on the compensation harmonic voltages of specified harmonics on the d-axis and q-axis. Specifically, the voltage compensation for specified harmonic disturbances in the high-voltage direct current transmission system based on the compensation harmonic voltage of specified harmonics along the d-axis and q-axis includes: Obtain the actual output voltage after voltage compensation by the PI controller in the inner current loop of the static synchronous compensator; The difference between the actual voltage and the compensation harmonic voltages of the specified harmonics on the d-axis and q-axis is calculated to obtain the output voltage after compensation for the specified harmonics, so as to perform voltage compensation for the specified harmonic disturbances on the high voltage direct current transmission system based on the output voltage.

2. The method as described in claim 1, characterized in that, The design of the sliding mode disturbance observer is shown in the following equation: In the formula: and The d-axis and q-axis components of the observed current estimated by the sliding mode disturbance observer. , These are the equivalent resistance and equivalent inductance from the AC side of the static synchronous compensator to the grid connection point, respectively. , These are the d-axis and q-axis components of the three-phase voltage at the grid connection point bus, respectively. , These are the d-axis and q-axis components of the three-phase voltage on the AC side of the static synchronous compensator, respectively. The angular frequency of the high-voltage direct current transmission system is... , The d-axis and q-axis components of the disturbance term of the high-voltage direct current transmission system estimated by the sliding mode disturbance observer. , It is the preset sliding mode gain coefficient; , This is the preset error gain coefficient; , The boundary layer thickness is a saturation function. It is a saturation function. and These are the d-axis and q-axis components of the current error, respectively.

3. The method as described in claim 1, characterized in that, The compensation harmonic voltages for the specified harmonics along the d-axis and q-axis are calculated using the following formula: In the formula, and Specify the compensation harmonic voltages for the subharmonics on the d-axis and q-axis, respectively. Let h be the specified set of harmonics. The resonant gain coefficient of the h-th harmonic For Laplace variables, The fundamental frequency, and Let be the harmonic disturbance values ​​of the h-th harmonic along the d-axis and q-axis.

4. The method as described in claim 1, characterized in that, The state-space equation of the quasi-resonant term is expressed by the following equation: In the formula, Let h be the integral state variable of the h-th resonant controller. Let h be the differential state variable of the h-th resonant controller, where h is the specified harmonic. The fundamental frequency, For the damping ratio, For cutoff bandwidth, Let h be the resonant gain coefficient of the h-th harmonic. This is the time-domain representation of the input signal.

5. A harmonic compensation device based on a static synchronous compensator, characterized in that, The device includes: The model building unit is used to build a state-space model of the static synchronous compensator, including the disturbances of the high-voltage direct current transmission system, based on the circuit structure and parameters of the static synchronous compensator connected to the high-voltage direct current transmission system. The disturbance estimation unit is used to introduce a sliding mode disturbance observer into the current inner loop of the static synchronous compensator, to observe and estimate the disturbance terms in the state space model of the static synchronous compensator in real time, and to determine the disturbance terms of the high voltage DC transmission system. The voltage compensation unit is used to integrate based on the transfer function of the resonant controller and introduce the compensation voltage of the specified harmonic obtained by integration into the disturbance term of the high voltage direct current transmission system to compensate the voltage of the specified harmonic disturbance of the high voltage direct current transmission system. The voltage compensation unit is further configured to convert the transfer function of the resonant controller into a state-space form to obtain the quasi-resonant term state-space equation; perform a specified resonance integral based on the quasi-resonant term state-space equation to obtain the total resonance compensation output by the resonant controller; and introduce the total resonance compensation output by the resonant controller into the disturbance term of the high-voltage direct current transmission system to perform voltage compensation for the specified harmonic disturbance of the high-voltage direct current transmission system. The voltage compensation unit is further configured to decompose the total resonance compensation output of the resonance controller to obtain the d-axis resonance output and q-axis resonance output of the resonance controller in the dq synchronous rotating coordinate system; combine the d-axis resonance output and q-axis resonance output with the d-axis and q-axis components of the disturbance term of the high-voltage direct current transmission system to obtain the compensation harmonic voltages for specified harmonics in the d-axis and q-axis; and perform voltage compensation for specified harmonic disturbances in the high-voltage direct current transmission system based on the compensation harmonic voltages for specified harmonics in the d-axis and q-axis. The voltage compensation unit is also used to obtain the actual voltage output after voltage compensation by the PI controller in the inner current loop of the static synchronous compensator; and to calculate the difference between the actual voltage and the compensation harmonic voltage of the specified harmonics on the d-axis and q-axis to obtain the output voltage after compensation of the specified harmonics, so as to perform voltage compensation of the specified harmonic disturbance on the high voltage DC transmission system based on the output voltage.

6. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it causes the processor to perform the steps of the method as described in any one of claims 1 to 4.

7. A computer device, comprising a memory and a processor, characterized in that, The memory stores a computer program that, when executed by the processor, causes the processor to perform the steps of the method as described in any one of claims 1 to 4.

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