Reactive compensation control method and device for converter during fault ride-through period

Abstract

The invention provides a reactive compensation control method and device for a converter in a fault ride-through period, and the method comprises the steps: generating a control current through a pre-constructed converter current output model according to an initial power grid control parameter, a terminal voltage amplitude value and an initial current; constructing a transient voltage constraint condition and a current amplitude limiting constraint condition through a preset power grid limit value according to the control current and the transient voltage amplitude; and according to a transient voltage constraint condition, a current amplitude limiting constraint condition and the initial voltage, solving the constructed transient low-voltage analytic model and the transient overvoltage analytic model, generating an optimal converter voltage ride-through control parameter, and carrying out converter reactive compensation control according to the optimal converter voltage ride-through control parameter. Optimization of control parameters is achieved in an original optimization program, transient voltage out-of-limit of a system is avoided, and therefore transient voltage stability is met in the voltage fault ride-through process.

Description

Technical Field

[0001] The present invention relates to the field of electric power safety technology, and in particular to a method and device for controlling reactive power compensation of a converter during fault ride-through. Background Art

[0002] In a weak power grid with a high proportion of photovoltaic devices connected, the scenarios of voltage instability in the system are complex and diverse. For the transient voltage stability problem of the system, it is necessary to explore the impact of the asynchronous machine power supply on the system voltage stability in the key stage of the transient process according to the transient characteristics of the asynchronous machine power supply in the system. The process of maintaining the operation of power electronic equipment when the system voltage fluctuates due to the occurrence and clearance of faults is called voltage fault ride-through. In the prior art, voltage fault ride-through usually limits the current generated by the converter during the fault to avoid the converter outputting too high a current and burning the device when the voltage is too low; however, when the penetration rate of new energy is high, the asynchronous machine power supply that was originally unable to actively provide voltage support needs to issue reactive compensation in the fault ride-through link, resulting in the system transient voltage exceeding the limit, which cannot meet the transient voltage stability when new energy is connected on a large scale. Summary of the invention

[0003] One object of the present invention is to provide a method for controlling reactive power compensation of a converter during fault ride-through, to optimize control parameters in an existing optimization program, to avoid transient voltage exceeding the limit of the system, and to meet transient voltage stability during voltage fault ride-through. Another object of the present invention is to provide a device for controlling reactive power compensation of a converter during fault ride-through. Another object of the present invention is to provide a computer readable medium. Still another object of the present invention is to provide a computer device.

[0004] In order to achieve the above objectives, the present invention discloses, on one hand, a method for controlling reactive power compensation of a converter during fault ride-through, comprising:

[0005] Obtaining initial grid control parameters, terminal voltage amplitude, initial current, initial voltage and transient voltage amplitude during voltage fault ride-through;

[0006] Generate control current based on initial grid control parameters, terminal voltage amplitude and initial current through a pre-built converter current output model;

[0007] Through the preset grid limit, according to the control current and transient voltage amplitude, the transient voltage constraint condition and the current limit constraint condition are constructed;

[0008] According to the transient voltage constraints, current limit constraints and initial voltage, the constructed transient undervoltage analytical model and transient overvoltage analytical model are solved to generate the optimal converter voltage ride-through control parameters, and the converter reactive power compensation control is performed according to the optimal converter voltage ride-through control parameters.

[0009] Preferably, the voltage fault ride-through includes low voltage fault ride-through, the initial grid control parameters include a voltage coefficient of an initial active current, a current coefficient of an initial active current, an active current reference value, a voltage coefficient of an initial reactive current, a current coefficient of an initial reactive current, and a reactive current reference value, the converter current output model includes an active current output model and a reactive current output model, the initial current includes an initial active current and an initial reactive current, and the control current includes an output active current and an output reactive current;

[0010] The control current is generated through the pre-built converter current output model according to the initial grid control parameters, the terminal voltage amplitude and the initial current, including:

[0011] Generate the output active current during the low voltage fault ride-through period through the active current output model according to the voltage coefficient of the initial active current, the current coefficient of the initial active current, the active current reference value, the terminal voltage amplitude and the initial active current;

[0012] Through the reactive current output model, the output reactive current during low voltage fault ride-through is generated according to the voltage coefficient of the initial reactive current, the current coefficient of the initial reactive current, the reactive current reference value, the machine-end voltage amplitude, the preset first voltage threshold and the initial reactive current.

[0013] Preferably, the voltage fault ride-through includes a high voltage fault ride-through, the initial grid control parameters include a voltage coefficient of an initial active current, a current coefficient of an initial active current, an active current reference value, a voltage coefficient of an initial reactive current, a current coefficient of an initial reactive current, and a reactive current reference value, the converter current output model includes an active current output model and a reactive current output model, the initial current includes an initial active current and an initial reactive current, and the control current includes an output active current and an output reactive current;

[0014] The control current is generated through the pre-built converter current output model according to the initial grid control parameters, the terminal voltage amplitude and the initial current, including:

[0015] Generate the output active current during high voltage fault ride-through by using the active current output model according to the voltage coefficient of the initial active current, the current coefficient of the initial active current, the active current reference value, the voltage amplitude at the machine end and the initial active current;

[0016] Through the reactive current output model, the output reactive current during high voltage fault ride-through is generated according to the voltage coefficient of the initial reactive current, the current coefficient of the initial reactive current, the reactive current reference value, the machine-end voltage amplitude, the preset second voltage threshold and the initial reactive current.

[0017] Preferably, the method further comprises:

[0018] generating voltage control parameter sensitivity during low voltage fault ride-through according to initial grid control parameters and initial voltage;

[0019] According to the voltage control parameter sensitivity, initial grid control parameters and initial voltage during low voltage fault ride-through, a transient low voltage analytical model is constructed;

[0020] generating low voltage control parameter sensitivity during high voltage fault ride-through according to the initial grid control parameters;

[0021] generating a high voltage control parameter sensitivity during a high voltage fault ride-through period according to the initial grid control parameter and the initial voltage;

[0022] A transient overvoltage analytical model is constructed based on the low voltage control parameter sensitivity during high voltage fault ride-through, the high voltage control parameter sensitivity during high voltage fault ride-through, the initial grid control parameters and the initial voltage.

[0023] Preferably, the optimal converter voltage ride-through control parameters include optimal transient undervoltage control parameters and optimal transient overvoltage control parameters;

[0024] According to the transient voltage constraint conditions, current limit constraint conditions and initial voltage, the constructed transient low voltage analytical model and transient overvoltage analytical model are solved to generate the optimal converter voltage ride-through control parameters, and the converter reactive power compensation control is performed according to the optimal converter voltage ride-through control parameters, including:

[0025] The transient low voltage analytical model is solved through transient voltage constraints, current limit constraints and initial voltage to generate optimal transient low voltage control parameters, and the converter reactive power compensation control is performed according to the optimal transient low voltage control parameters;

[0026] The transient overvoltage analytical model is solved through transient voltage constraints, current limit constraints and initial voltage, and the optimal transient overvoltage control parameters are generated. The converter reactive power compensation control is then performed according to the optimal transient overvoltage control parameters.

[0027] The present invention also discloses a converter reactive power compensation control device during fault ride-through, comprising:

[0028] An acquisition unit, used to acquire initial grid control parameters, terminal voltage amplitude, initial current, initial voltage and transient voltage amplitude during voltage fault ride-through;

[0029] A control current generating unit, used for generating a control current according to an initial grid control parameter, a terminal voltage amplitude and an initial current through a pre-built converter current output model;

[0030] A constraint condition generating unit, used for constructing transient voltage constraint conditions and current limit constraint conditions according to the control current and transient voltage amplitude through the preset grid limit value;

[0031] The control parameter solving unit is used to solve the constructed transient low voltage analytical model and transient overvoltage analytical model according to the transient voltage constraint conditions, the current limit constraint conditions and the initial voltage, generate the optimal converter voltage ride-through control parameters, and perform converter reactive power compensation control according to the optimal converter voltage ride-through control parameters.

[0032] Preferably, the voltage fault ride-through includes low voltage fault ride-through, the initial grid control parameters include a voltage coefficient of an initial active current, a current coefficient of an initial active current, an active current reference value, a voltage coefficient of an initial reactive current, a current coefficient of an initial reactive current, and a reactive current reference value, the converter current output model includes an active current output model and a reactive current output model, the initial current includes an initial active current and an initial reactive current, and the control current includes an output active current and an output reactive current;

[0033] The control current generating unit is specifically used to generate the output active current during the low voltage fault ride-through through the active current output model according to the voltage coefficient of the initial active current, the current coefficient of the initial active current, the active current reference value, the machine-end voltage amplitude and the initial active current; and to generate the output reactive current during the low voltage fault ride-through through the reactive current output model according to the voltage coefficient of the initial reactive current, the current coefficient of the initial reactive current, the reactive current reference value, the machine-end voltage amplitude, the preset first voltage threshold and the initial reactive current.

[0034] Preferably, the voltage fault ride-through includes a high voltage fault ride-through, the initial grid control parameters include a voltage coefficient of an initial active current, a current coefficient of an initial active current, an active current reference value, a voltage coefficient of an initial reactive current, a current coefficient of an initial reactive current, and a reactive current reference value, the converter current output model includes an active current output model and a reactive current output model, the initial current includes an initial active current and an initial reactive current, and the control current includes an output active current and an output reactive current;

[0035] The control current generating unit is specifically used to generate the output active current during the high voltage fault ride-through through the active current output model according to the voltage coefficient of the initial active current, the current coefficient of the initial active current, the active current reference value, the machine-end voltage amplitude and the initial active current; and to generate the output reactive current during the high voltage fault ride-through through the reactive current output model according to the voltage coefficient of the initial reactive current, the current coefficient of the initial reactive current, the reactive current reference value, the machine-end voltage amplitude, the preset second voltage threshold and the initial reactive current.

[0036] Preferably, the device further comprises:

[0037] A first sensitivity generating unit, configured to generate a voltage control parameter sensitivity during a low voltage fault ride-through period according to an initial grid control parameter and an initial voltage;

[0038] A transient low voltage model building unit, used to build a transient low voltage analytical model according to the voltage control parameter sensitivity, initial grid control parameters and initial voltage during the low voltage fault ride-through period;

[0039] A second sensitivity generating unit, configured to generate a low voltage control parameter sensitivity during a high voltage fault ride-through period according to the initial power grid control parameter;

[0040] A third sensitivity generating unit, configured to generate a high voltage control parameter sensitivity during a high voltage fault ride-through period according to the initial grid control parameter and the initial voltage;

[0041] The transient overvoltage model building unit is used to build a transient overvoltage analytical model according to the low voltage control parameter sensitivity during the high voltage fault ride-through period, the high voltage control parameter sensitivity during the high voltage fault ride-through period, the initial power grid control parameters and the initial voltage.

[0042] Preferably, the optimal converter voltage ride-through control parameter includes an optimal transient undervoltage control parameter and an optimal transient overvoltage control parameter;

[0043] The control parameter solving unit is specifically used to solve the transient low voltage analytical model through transient voltage constraints, current limit constraints and initial voltage, generate optimal transient low voltage control parameters, and perform reactive power compensation control of the converter according to the optimal transient low voltage control parameters; solve the transient overvoltage analytical model through transient voltage constraints, current limit constraints and initial voltage, generate optimal transient overvoltage control parameters, and perform reactive power compensation control of the converter according to the optimal transient overvoltage control parameters.

[0044] The present invention also discloses a computer-readable medium on which a computer program is stored. When the program is executed by a processor, the method described above is implemented.

[0045] The present invention also discloses a computer device, including a memory and a processor, wherein the memory is used to store information including program instructions, the processor is used to control the execution of program instructions, and the processor implements the above method when executing the program.

[0046] The present invention also discloses a computer program product, including a computer program / instruction, and the method described above is implemented when the computer program / instruction is executed by a processor.

[0047] The present invention obtains initial grid control parameters, machine-end voltage amplitude, initial current, initial voltage and transient voltage amplitude during voltage fault ride-through; generates control current according to initial grid control parameters, machine-end voltage amplitude and initial current through a pre-constructed converter current output model; constructs transient voltage constraint conditions and current limit constraint conditions according to control current and transient voltage amplitude through preset grid limits; solves the constructed transient low voltage analytical model and transient overvoltage analytical model according to transient voltage constraint conditions, current limit constraint conditions and initial voltage, generates optimal converter voltage ride-through control parameters, and performs converter reactive power compensation control according to the optimal converter voltage ride-through control parameters, realizes optimization of control parameters in the original optimization program, avoids system transient voltage exceeding the limit, and thus satisfies transient voltage stability during voltage fault ride-through. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 paying creative work.

[0049] Figure 1 A flowchart of a method for controlling reactive power compensation of a converter during fault ride-through provided by an embodiment of the present invention;

[0050] Figure 2 A flowchart of another method for controlling reactive power compensation of a converter during fault ride-through provided by an embodiment of the present invention;

[0051] Figure 3 A schematic structural diagram of a converter reactive power compensation control device during fault ride-through provided by an embodiment of the present invention;

[0052] Figure 4 A schematic diagram of the structure of a computer device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0053] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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 are within the scope of protection of the present invention.

[0054] It should be noted that the method and device for reactive power compensation control of a converter during fault ride-through disclosed in the present application can be used in the field of artificial intelligence technology, and can also be used in any field outside the field of artificial intelligence technology. The application field of the method and device for reactive power compensation control of a converter during fault ride-through disclosed in the present application is not limited.

[0055] In order to facilitate the understanding of the technical solution provided by the present application, the relevant contents of the technical solution of the present application are first explained below. At present, the installed capacity and penetration rate of renewable energy are constantly increasing. As renewable energy continues to replace traditional synchronous generators, the voltage support capacity of the power grid has changed significantly. First, when new energy units are connected to the AC power grid, they rely on power electronic devices such as converters, which are different from the synchronous generators of traditional thermal power generation. The large-scale non-synchronous machines make the system lack synchronous support, and the strength and voltage support capacity of the power grid have declined. They generally present the form of a weak power grid, which makes the power grid prone to voltage stability problems and significantly increases the risk; second, there is coupling interaction between the power electronic equipment connected to the power grid, and the application of technologies such as voltage source control makes the transient voltage stability characteristics change profoundly after a power grid failure, which also has a significant impact on voltage stability.

[0056] The present invention first proposes a model of the active and reactive components of the output current with respect to the fault ride-through control parameters, and then establishes a transient voltage analytical model with the fault ride-through control parameters as variables through trajectory sensitivity, and constructs transient undervoltage / overvoltage constraints and current limiting constraints according to stability requirements, thereby optimizing the control parameters in the original optimization program, so that the designed control strategy can meet the transient voltage stability during the voltage fault ride-through process.

[0057] The following takes the converter reactive compensation control device during fault ride-through as an example to illustrate the implementation process of the converter reactive compensation control method during fault ride-through provided by the embodiment of the present invention. It can be understood that the execution subject of the converter reactive compensation control method during fault ride-through provided by the embodiment of the present invention includes but is not limited to the converter reactive compensation control device during fault ride-through.

[0058] Figure 1 A flowchart of a method for controlling reactive power compensation of a converter during fault ride-through provided by an embodiment of the present invention is shown in FIG. Figure 1 As shown, the method includes:

[0059] Step 101: Obtain initial grid control parameters, terminal voltage amplitude, initial current, initial voltage, and transient voltage amplitude during voltage fault ride-through.

[0060] Step 102: Generate a control current through a pre-built converter current output model according to initial grid control parameters, terminal voltage amplitude and initial current.

[0061] In an embodiment of the present invention, voltage fault ride-through includes low voltage fault ride-through, the initial grid control parameters include the voltage coefficient of the initial active current, the current coefficient of the initial active current, the active current reference value, the voltage coefficient of the initial reactive current, the current coefficient of the initial reactive current, the reactive current reference value, the converter current output model includes an active current output model and a reactive current output model, the initial current includes an initial active current and an initial reactive current, and the control current includes an output active current and an output reactive current.

[0062] In an embodiment of the present invention, voltage fault ride-through includes high voltage fault ride-through, the initial grid control parameters include a voltage coefficient of an initial active current, a current coefficient of an initial active current, an active current reference value, a voltage coefficient of an initial reactive current, a current coefficient of an initial reactive current, and a reactive current reference value, the converter current output model includes an active current output model and a reactive current output model, the initial current includes an initial active current and an initial reactive current, and the control current includes an output active current and an output reactive current.

[0063] Step 103: construct transient voltage constraint conditions and current limit constraint conditions according to preset grid limits, control current and transient voltage amplitude.

[0064] Step 104: Solve the constructed transient low voltage analytical model and transient overvoltage analytical model according to the transient voltage constraint condition, the current limit constraint condition and the initial voltage, generate optimal converter voltage ride-through control parameters, and perform converter reactive power compensation control according to the optimal converter voltage ride-through control parameters.

[0065] In the embodiment of the present invention, the optimal converter voltage ride-through control parameter includes an optimal transient undervoltage control parameter and an optimal transient overvoltage control parameter.

[0066] In the technical solution provided by the embodiment of the present invention, the initial grid control parameters, the machine-end voltage amplitude, the initial current, the initial voltage and the transient voltage amplitude during the voltage fault ride-through are obtained; the control current is generated according to the initial grid control parameters, the machine-end voltage amplitude and the initial current through the pre-constructed converter current output model; the transient voltage constraint condition and the current limit constraint condition are constructed according to the control current and the transient voltage amplitude through the preset grid limit; according to the transient voltage constraint condition, the current limit constraint condition and the initial voltage, the constructed transient low voltage analytical model and the transient overvoltage analytical model are solved to generate the optimal converter voltage ride-through control parameters, and the converter reactive power compensation control is performed according to the optimal converter voltage ride-through control parameters, and the optimization of the control parameters is realized in the original optimization program to avoid the system transient voltage exceeding the limit, thereby satisfying the transient voltage stability during the voltage fault ride-through process.

[0067] Figure 2 A flowchart of another method for controlling reactive power compensation of a converter during fault ride-through provided by an embodiment of the present invention is shown in FIG. Figure 2 As shown, the method includes:

[0068] Step 201: Obtain initial grid control parameters, terminal voltage amplitude, initial current, initial voltage and transient voltage amplitude during voltage fault ride-through.

[0069] In the embodiment of the present invention, each step is executed by the converter reactive power compensation control device during fault ride-through.

[0070] In an embodiment of the present invention, the initial grid control parameters include the voltage coefficient of the initial active current, the current coefficient of the initial active current, the active current reference value, the voltage coefficient of the initial reactive current, the current coefficient of the initial reactive current, and the reactive current reference value.

[0071] Step 202: Generate a control current through a pre-built converter current output model according to initial grid control parameters, terminal voltage amplitude and initial current.

[0072] After a power grid failure, the system voltage drops, and the converter will significantly increase the output current to maintain power output, which may cause the device to burn out. In addition, the converter cannot continue to provide voltage support like a synchronous generator. Therefore, in systems with a high penetration rate of new energy, the converter needs to provide additional reactive power compensation during the voltage crossing process to maintain transient voltage stability. When a system failure occurs, the converter enters the low voltage fault crossing (Low Voltage RideThrough, referred to as: LVRT) stage, at which time the output current needs to be controlled. Constructing a converter current output model can better control the output of the converter.

[0073] In an embodiment of the present invention, voltage fault ride-through includes LVRT, the converter current output model includes an active current output model during LVRT and a reactive current output model during LVRT, the initial current includes an initial active current during LVRT and an initial reactive current during LVRT, and the control current includes an output active current during LVRT and an output reactive current during LVRT.

[0074] In the embodiment of the present invention, step 202 specifically includes:

[0075] Step 2021: Generate the output active current during the LVRT period through the active current output model according to the voltage coefficient of the initial active current, the current coefficient of the initial active current, the active current reference value, the machine-end voltage amplitude and the initial active current.

[0076] The active current output model of the converter during LVRT is assumed to be:

[0077] I p,LVRT =K 1Ip,LV V t +K 2Ip,LV I p0 +I pset,LV

[0078] Among them, I p,LVRT is the output active current during LVRT, K 1Ip,LV is the voltage coefficient of the initial active current during LVRT, V t is the terminal voltage amplitude during LVRT, K 2Ip,LV is the current coefficient of the initial active current during LVRT, I p0 is the initial active current during LVRT, I pset,LV It is the active current reference value during LVRT.

[0079] Step 2022: Generate the output reactive current during low voltage fault ride-through through the reactive current output model according to the voltage coefficient of the initial reactive current, the current coefficient of the initial reactive current, the reactive current reference value, the machine-end voltage amplitude, the preset first voltage threshold and the initial reactive current.

[0080] The reactive current output model of the converter during LVRT is set as:

[0081] I q,LVRT =K 1Iq,LV (V L -V t )+K 2Iq,LV I q0 +I qset,LV

[0082] Among them, I q,LVRTis the output reactive current during LVRT, K 1Iq,LV is the voltage coefficient of the initial reactive current during LVRT, V L is the first voltage threshold, V t is the terminal voltage amplitude during LVRT, K 2Iq,LV is the current coefficient of the initial reactive current during LVRT, I q0 is the initial reactive current during LVRT, I qset,LV It is the reactive current reference value during LVRT.

[0083] It is worth noting that the first voltage threshold is the voltage threshold at which the converter enters the LVRT process from the normal operating condition.

[0084] In summary, the constructed active current output model and reactive current output model are controlled by the voltage and current before the fault, as well as the key parameters of the control module inside the converter. The model indicates that when the grid voltage drops sharply, the control strategy makes the active current component I p,LVRT Drop, reactive current component I q,LVRT Such a control strategy increases the voltage support provided by the photovoltaic converter compared to when it is uncontrolled, thereby providing additional voltage support for the power grid and helping to suppress transient low voltage problems.

[0085] Similarly, after the fault is cleared, the system voltage rises and the converter enters the high voltage fault ride through (High Voltage Ride Through, HVRT for short). At this time, the converter current output model during the HVRT period is constructed.

[0086] Voltage fault ride-through includes HVRT, initial grid control parameters include voltage coefficient of initial active current during HVRT, current coefficient of initial active current during HVRT, active current reference value during HVRT, voltage coefficient of initial reactive current during HVRT, current coefficient of initial reactive current during HVRT, reactive current reference value during HVRT, converter current output model includes active current output model during HVRT and reactive current output model during HVRT, initial current includes initial active current during HVRT and initial reactive current during HVRT, control current includes output active current during HVRT and output reactive current during HVRT.

[0087] In the embodiment of the present invention, step 202 specifically includes:

[0088] Step 3021: Generate the output active current during high voltage fault ride-through through the active current output model according to the voltage coefficient of the initial active current, the current coefficient of the initial active current, the active current reference value, the machine-end voltage amplitude and the initial active current.

[0089] The active current output model of the converter during HVRT is set as:

[0090] I p,HVRT =K 1Ip,HV V t +K 2Ip,HV I p0 +I pset,HV

[0091] Among them, I p,HVRT is the output active current during HVRT, K 1Ip,HV is the voltage coefficient of the initial active current during HVRT, V t is the terminal voltage amplitude during HVRT, K 2Ip,HV is the current coefficient of the initial active current during HVRT, I p0 is the initial active current during HVRT, I pset,HV It is the active current reference value during HVRT.

[0092] Step 3022: Generate the output reactive current during HVRT through the reactive current output model according to the voltage coefficient of the initial reactive current, the current coefficient of the initial reactive current, the reactive current reference value, the machine-end voltage amplitude, the preset second voltage threshold and the initial reactive current.

[0093] The reactive current output model of the converter during HVRT is set as:

[0094] I q,HVRT =K 1Iq,HV (V H -V t )+K 2Iq,HV I q0 +I qset,HV

[0095] Among them, I q,HVRT is the output reactive current during HVRT, K 1Iq,HV is the voltage coefficient of the initial reactive current during HVRT, V H is the second voltage threshold, V t is the terminal voltage amplitude during HVRT, K 2Iq,HV is the current coefficient of the initial reactive current during HVRT, I q0 is the initial reactive current during HVRT, I qset,HV It is the reactive current reference value during HVRT.

[0096] It is worth noting that the second voltage threshold is a voltage threshold at which the converter enters HVRT from a normal operating condition.

[0097] In summary, the model indicates that when the grid voltage increases, the control strategy makes the active current component I p,HVRT Rise, reactive current component I q,HVRT Such a control strategy enables the converter to provide less voltage support than when it is not affected by the strategy, which is beneficial to suppress transient overvoltage problems.

[0098] Step 203: Generate voltage control parameter sensitivity during low voltage fault ride-through according to the initial grid control parameter and the initial voltage.

[0099] In the embodiment of the present invention, after constructing the converter output current model including various control parameters, in order to achieve the goal of controlling transient voltage and enhancing voltage stability, it is necessary to determine the value of the control parameter according to the degree to which the transient voltage amplitude is affected by each control parameter. In the power system, the degree of influence of the transient voltage can be measured by calculating the sensitivity of the transient voltage relative to the current control parameter.

[0100] Specifically, during the voltage ride-through process, the voltage at the grid-connected point of the converter is mainly affected by the reactive current output by the converter. Therefore, the transient voltage V pv,LV The sensitivity of each control parameter relative to the reactive current, among which the transient voltage V pv,LV Relative to LVRT voltage coefficient K 1Iq,LV The expression of trajectory sensitivity is:

[0101]

[0102] Among them, S K1,LV (t k ,K 1Iq,LV ) is the transient voltage V in LVRT pv,LV Relative to LVRT voltage coefficient K 1Iq,LV Trajectory sensitivity, t k is the time variable, K 1Iq,LV is the voltage coefficient of the initial reactive current during LVRT, V pv,LV (t k ,K 1Iq,LV ) is the time t in LVRT k The voltage coefficient curve of the variable.

[0103] LVRT transient voltage V pv,LV Relative to LVRT reactive current coefficient K 2Iq,LV The expression of trajectory sensitivity is:

[0104]

[0105] Among them, S K2,LV (t k ,K 2Iq,LV ) is the transient voltage V in LVRT pv,LV Relative to LVRT reactive current coefficient K 2Iq,LV Trajectory sensitivity, t k is the time variable, K 2Iq,LV is the current coefficient of the initial reactive current during LVRT, V pv,LV (t k ,K 2Iq,LV ) is the time t in LVRT k Current coefficient curve for the variable.

[0106] LVRT transient voltage V pv,LV Relative to LVRT reactive current reference value I qset,LV The expression of trajectory sensitivity is:

[0107]

[0108] Among them, S Iqset,LV (t k ,I qset,LV ) is the transient voltage V pv,LV Relative to LVRT reactive current reference value I qset,LV Trajectory sensitivity, t k is the time variable, I qset,LV is the reactive current reference value during LVRT, V pv,LV (t k ,I qset,LV ) is the time t in LVRT k The reactive current reference value curve is a variable.

[0109] LVRT transient voltage V pv,LV The expression of trajectory sensitivity relative to the LVRT initial voltage V0 is:

[0110]

[0111] Among them, S V0,LV (t k , V0) is the transient voltage V pv,LV Trajectory sensitivity relative to LVRT initial voltage V0, t k is the time variable, V0 is the initial voltage during LVRT, V pv,LV (t k , V0) is the time t in LVRT kis the initial voltage curve of the variable.

[0112] Step 204: construct a transient low voltage analytical model according to the voltage control parameter sensitivity, the initial grid control parameters and the initial voltage during the low voltage fault ride-through period.

[0113] In the embodiment of the present invention, the reactive current control parameters include an LVRT voltage coefficient, an LVRT reactive current coefficient, an LVRT reactive current reference value and an LVRT initial voltage.

[0114] Specifically, according to the LVRT voltage coefficient, LVRT reactive current coefficient, LVRT reactive current reference value, LVRT initial voltage and their corresponding sensitivity, a transient low voltage analytical model with each control parameter as a variable is established:

[0115] V pv,LV =V 0L +S V0,LV V0+S K1,LV K 1Iq,LV +S K2,LV K 2Iq,LV +S Iqset,LV I qset,LV

[0116] Among them, V pv,LV For transient low voltage, V 0L is a constant term, S K1,LV is the transient voltage V in LVRT pv,LV Relative to LVRT voltage coefficient K 1Iq,LV The trajectory sensitivity, K 1Iq,LV is the voltage coefficient of the initial reactive current during LVRT, S K2,LV is the transient voltage V in LVRT pv,LV Relative to LVRT reactive current coefficient K 2Iq,LV The trajectory sensitivity, K 2Iq,LV is the current coefficient of the initial reactive current during LVRT, S Iqset,LV is the transient voltage V pv,LV Relative to LVRT reactive current reference value I qset,LV The trajectory sensitivity, I qset,LV is the reactive current reference value during LVRT, S V0,LV is the transient voltage V pv,LV Trajectory sensitivity relative to the LVRT initial voltage V0, where V0 is the initial voltage during the LVRT.

[0117] It is worth noting that the constant term V 0L It is the constant term part of the transient voltage in LVRT that is not affected by various control parameters.

[0118] Step 205: Generate low voltage control parameter sensitivity during high voltage fault ride-through according to the initial power grid control parameters.

[0119] When the fault is cleared, the system voltage rises and the converter enters the HVRT process. At this time, the transient voltage is not only affected by the various control parameters in the HVRT, but also determined by the voltage level at the end of the LVRT, that is, it is affected by the various control parameters in the LVRT. Calculate the transient voltage V in the HVRT separately. pv,LV Sensitivity of each reactive current control parameter relative to LVRT.

[0120] Among them, the transient voltage V pv,LV Relative to LVRT voltage coefficient K 1Iq,LV The expression of trajectory sensitivity is:

[0121]

[0122] Among them, S K1L,HV (t k ,K 1Iq,LV ) is the transient voltage V in HVRT pv,LV Relative to LVRT voltage coefficient K 1Iq,LV Trajectory sensitivity, t k is the time variable, K 1Iq,LV is the voltage coefficient of the initial reactive current during LVRT, V pv,HV (t k ,K 1Iq,LV ) is the time t in HVRT k The voltage coefficient curve of the variable.

[0123] HVRT transient voltage V pv,LV Relative to LVRT reactive current coefficient K 2Iq,LV The expression of trajectory sensitivity is:

[0124]

[0125] Among them, S K2L,HV (t k ,K 2Iq,LV ) is the transient voltage V in HVRT pv,LV Relative to LVRT reactive current coefficient K 2Iq,LV Trajectory sensitivity, t k is the time variable, K 2Iq,LV is the current coefficient of the initial reactive current during LVRT, V pv,HV (t k ,K 2Iq,LV ) is the time t in HVRT k Current coefficient curve for the variable.

[0126] HVRT transient voltage V pv,LV Relative to LVRT reactive current reference value I qset,LV The expression of trajectory sensitivity is:

[0127]

[0128] Among them, S IqsetL,HV (t k ,I qset,LV ) is the transient voltage V in HVRT pv,LV Relative to LVRT reactive current reference value I qset,LV Trajectory sensitivity, t k is the time variable, I qset,LV is the reactive current reference value during LVRT, V pv,HV (t k ,I qset,LV ) is the time t in HVRT k The reactive current reference value curve is a variable.

[0129] Step 206: Generate a high voltage control parameter sensitivity during a high voltage fault ride-through period according to the initial grid control parameter and the initial voltage.

[0130] Specifically, calculate the transient voltage V in HVRT respectively. pv,LV Sensitivity of each reactive current control parameter relative to HVRT.

[0131] HVRT transient voltage V pv,LV Relative to HVRT voltage coefficient K 1Iq,LV The expression of trajectory sensitivity is:

[0132]

[0133] Among them, S K1,HV (t k ,K 1Iq,HV ) is the transient voltage V in HVRT pv,LV Relative to HVRT voltage coefficient K 1Iq,LV Trajectory sensitivity, t k is the time variable, K 1Iq,HV is the voltage coefficient of the initial reactive current during HVRT, V pv,HV (t k ,K 1Iq,HV ) is the time t in HVRT k The voltage coefficient reference value curve of the variable.

[0134] HVRT transient voltage V pv,LV Relative to HVRT reactive current coefficient K 2Iq,HVThe expression of trajectory sensitivity is:

[0135]

[0136] Among them, S K2,HV (t k ,K 2Iq,HV ) is the transient voltage V in HVRT pv,LV Relative to HVRT reactive current coefficient K 2Iq,HV Trajectory sensitivity, t k is the time variable, K 2Iq,HV is the current coefficient of the initial reactive current during HVRT, V pv,HV (t k ,K 2Iq,HV ) is the time t in HVRT k Current coefficient curve for the variable.

[0137] HVRT transient voltage V pv,LV Relative to HVRT reactive current reference value I qset,HV The expression of trajectory sensitivity is:

[0138]

[0139] Among them, S Iqset,HV (t k ,I qset,HV ) is the transient voltage V in HVRT pv,LV Relative to HVRT reactive current reference value I qset,HV Trajectory sensitivity, t k is the time variable, I qset,HV is the reactive current reference value during HVRT, V pv,HV (t k ,I qset,HV ) is the time t in HVRT k The reactive current reference value curve is a variable.

[0140] HVRT transient voltage V pv,LV The expression of trajectory sensitivity relative to the HVRT initial voltage V0 is:

[0141]

[0142] Among them, S V0,HV (t k , V0) is the transient voltage V pv,LV Trajectory sensitivity relative to HVRT initial voltage V0, t k is the time variable, V0 is the initial voltage during HVRT, V pv,HV (t k , V0) is the time t in HVRTk is the initial voltage curve of the variable.

[0143] Step 207: construct a transient overvoltage analytical model according to the low voltage control parameter sensitivity during the HVRT period, the high voltage control parameter sensitivity during the HVRT period, the initial grid control parameters and the initial voltage.

[0144] In the embodiment of the present invention, the low voltage control parameters during HVRT include LVRT voltage coefficient, LVRT reactive current coefficient and LVRT reactive current reference value. The high voltage control parameters during HVRT include HVRT voltage coefficient, HVRT reactive current coefficient, HVRT reactive current reference value and HVRT initial voltage.

[0145] Specifically, according to the LVRT voltage coefficient, LVRT reactive current coefficient, LVRT reactive current reference value and their corresponding low voltage control parameter sensitivity during HVRT, as well as the HVRT voltage coefficient, HVRT reactive current coefficient, HVRT reactive current reference value and HVRT initial voltage and their corresponding high voltage control parameter sensitivity during HVRT, a transient overvoltage analytical model with each control parameter as a variable is established:

[0146] V pv,HV =V 0H +S V0,HV V0+S K1L,HV K 1Iq,LV +S K2L,HV K 2Iq,LV +S IqsetL,HV I qset,LV +

[0147] S K1,HV K 1Iq,HV +S K2,HV K 2Iq,HV +S Iqset,HV I qset,HV

[0148] Among them, V pv,HV For transient low voltage, V 0H is a constant term, S V0,HV is the transient voltage V pv,LV The trajectory sensitivity relative to the HVRT initial voltage V0, V0 is the initial voltage during HVRT, S K1L,HV is the transient voltage V in HVRT pv,LV Relative to LVRT voltage coefficient K 1Iq,LV The trajectory sensitivity, K 1Iq,LV is the voltage coefficient of the initial reactive current during LVRT, S K2L,HV is the transient voltage V in HVRT pv,LVRelative to LVRT reactive current coefficient K 2Iq,LV The trajectory sensitivity, K 2Iq,LV is the current coefficient of the initial reactive current during LVRT, S IqsetL,HV HVRT transient voltage V pv,LV Relative to LVRT reactive current reference value I qset,LV The trajectory sensitivity, I qset,LV is the reactive current reference value during LVRT, S K1,HV is the transient voltage V in HVRT pv,LV Relative to HVRT voltage coefficient K 1Iq,LV The trajectory sensitivity, K 1Iq,HV is the voltage coefficient of the initial reactive current during HVRT, S K2,HV is the transient voltage V in HVRT pv,LV Relative to HVRT reactive current coefficient K 2Iq,HV The trajectory sensitivity, K 2Iq,HV is the current coefficient of the initial reactive current during HVRT, S Iqset,HV is the transient voltage V in HVRT pv,LV Relative to HVRT reactive current reference value I qset,HV The trajectory sensitivity, I qset,HV It is the reactive current reference value during HVRT.

[0149] It is worth noting that the constant term V 0H It is the constant term part of the transient voltage in HVRT that is not affected by various control parameters.

[0150] Step 208: construct transient voltage constraint conditions and current limit constraint conditions according to the preset grid limit values, the control current and the transient voltage amplitude.

[0151] In the embodiment of the present invention, when solving the problem of power system stability, the transient voltage stability is rewritten as an inequality constraint to facilitate the calculation of the optimization problem. Based on the constructed transient low voltage analytical model and transient overvoltage analytical model, a transient voltage constraint condition is proposed to ensure that the system does not exceed the voltage limit during fault ride-through.

[0152] In the embodiment of the present invention, the grid limit includes the minimum voltage limit specified in the LVRT process for maintaining the operation of the equipment, the maximum voltage limit specified in the HVRT process for maintaining the operation of the equipment, the maximum limit of the converter output current in the LVRT process, and the maximum limit of the converter output current in the HVRT process.

[0153] Specifically, the transient voltage constraint conditions are constructed based on the transient voltage amplitude, the minimum voltage limit specified in the LVRT process to keep the equipment running, and the maximum voltage limit specified in the HVRT process to keep the equipment running:

[0154] V LVRT,th ≤V f pv,LV ≤V HVRT,th , f∈S f

[0155] V LVRT,th ≤V f pv,HV ≤V HVRT,th , f∈S f

[0156] Among them, V LVRT,th V is the minimum voltage limit specified in the LVRT process to keep the equipment running. f pv,LV is the transient voltage amplitude at the grid connection point of the converter after a fault occurs during the LVRT process, V HVRT,th is the maximum voltage limit specified in the HVRT process to keep the equipment running, f is the fault, S f is the typical fault set of the system, V f pv,HV is the transient voltage amplitude at the grid-connected point of the converter after a fault occurs during the HVRT process.

[0157] It is worth noting that the state variables in this constraint include all control parameters, namely: the reactive current control parameter K in the LVRT process 1Iq,LV , K 2Iq,LV ,I qset,LV and the reactive current control parameter K during HVRT 1Iq,HV , K 2Iq,HV ,I qset,HV .

[0158] In the embodiment of the present invention, the control current includes the output active current during LVRT, the output reactive current during LVRT, the output active current during HVRT, and the output reactive current during HVRT.

[0159] In the voltage ride-through phase, in order to prevent the converter from burning out due to excessive current, current limiting constraints need to be introduced:

[0160] I 2 p,LVRT +I 2 q,LVRT ≤I 2 max,LVRT

[0161] I 2 p,HVRT +I 2 q,HVRT ≤I 2 max,HVRT

[0162] Among them, I p,LVRT is the output active current during LVRT, I q,LVRT is the output reactive current during LVRT, I max,LVRT is the maximum limit of the converter output current during LVRT, I p,HVRT is the output active current during HVRT, I q,HVRT is the output reactive current during HVRT, I max,HVRT It is the maximum limit of the converter output current during the HVRT process.

[0163] Step 209: Solve the transient low voltage analytical model through the transient voltage constraint condition, the current limit constraint condition and the initial voltage, generate the optimal transient low voltage control parameters, and perform the converter reactive power compensation control according to the optimal transient low voltage control parameters.

[0164] Specifically, the transient low voltage analytical model is used as the objective function, and the transient voltage constraint condition and the current limit constraint condition are used as the constraint conditions of the objective function. The optimal solution of the objective function is obtained according to the initial voltage, and the optimal transient low voltage control parameters are obtained, namely: the converter reactive power compensation control strategy, so as to ensure the transient voltage stability of the system.

[0165] In the embodiment of the present invention, the optimal transient low voltage control parameters include the LVRT voltage coefficient, the LVRT reactive current coefficient, the LVRT reactive current reference value and the LVRT initial voltage.

[0166] Step 210: Solve the transient overvoltage analytical model through transient voltage constraints, current limit constraints and initial voltage, generate optimal transient overvoltage control parameters, and perform converter reactive power compensation control according to the optimal transient overvoltage control parameters.

[0167] Specifically, the transient overvoltage analytical model is used as the objective function, and the transient voltage constraint condition and the current limit constraint condition are used as the constraint conditions of the objective function. The optimal solution of the objective function is obtained according to the initial voltage, and the optimal transient overvoltage control parameters are obtained, namely: the converter reactive power compensation control strategy, so as to ensure the transient voltage stability of the system.

[0168] In an embodiment of the present invention, the optimal transient overvoltage control parameters include the LVRT voltage coefficient, LVRT reactive current coefficient, LVRT reactive current reference value, HVRT voltage coefficient, HVRT reactive current coefficient, HVRT reactive current reference value and HVRT initial voltage during HVRT.

[0169] It is worth noting that the acquisition, storage, use, and processing of data in the technical solution of this application are in compliance with the relevant provisions of laws and regulations. The user information in the embodiments of this application is obtained through legal and compliant channels, and the acquisition, storage, use, and processing of user information are authorized and agreed by the customer.

[0170] It is worth noting that the information collected in this application is information and data authorized by the user or fully authorized by all parties, and the collection, storage, use, processing, transmission, provision, disclosure and application of relevant data comply with the relevant laws, regulations and standards of relevant countries and regions, take necessary confidentiality measures, do not violate public order and good customs, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0171] It is worth noting that the technical solution provided in this application provides users with corresponding operation entrances for them to choose to agree or reject the automated decision-making results; if the user chooses to reject, the expert decision-making process will be entered.

[0172] In the technical solution of the method for controlling reactive compensation of a converter during fault ride-through provided by an embodiment of the present invention, initial grid control parameters, machine-end voltage amplitude, initial current, initial voltage and transient voltage amplitude during voltage fault ride-through are obtained; a control current is generated according to the initial grid control parameters, machine-end voltage amplitude and initial current through a pre-constructed converter current output model; transient voltage constraints and current limit constraints are constructed according to the control current and transient voltage amplitude through preset grid limits; according to the transient voltage constraints, current limit constraints and initial voltage, the constructed transient low voltage analytical model and transient overvoltage analytical model are solved to generate optimal converter voltage ride-through control parameters, and converter reactive compensation control is performed according to the optimal converter voltage ride-through control parameters, so as to optimize the control parameters in the original optimization program and avoid system transient voltage exceeding the limit, thereby satisfying transient voltage stability during voltage fault ride-through.

[0173] Figure 3 A schematic diagram of the structure of a converter reactive compensation control device during fault ride-through provided by an embodiment of the present invention, the device is used to execute the converter reactive compensation control method during fault ride-through, such as Figure 3 As shown, the device includes: an acquisition unit 11, a control current generation unit 12, a constraint condition generation unit 13 and a control parameter solving unit 14.

[0174] The acquisition unit 11 is used to acquire the initial grid control parameters, the machine-end voltage amplitude, the initial current, the initial voltage and the transient voltage amplitude during the voltage fault ride-through period.

[0175] The control current generating unit 12 is used to generate the control current according to the initial grid control parameters, the machine terminal voltage amplitude and the initial current through the pre-built converter current output model.

[0176] The constraint condition generating unit 13 is used to construct transient voltage constraint conditions and current limit constraint conditions according to the preset grid limit value, the control current and the transient voltage amplitude.

[0177] The control parameter solving unit 14 is used to solve the constructed transient low voltage analytical model and transient overvoltage analytical model according to the transient voltage constraint conditions, the current limit constraint conditions and the initial voltage, generate the optimal converter voltage crossing control parameters, and perform converter reactive compensation control according to the optimal converter voltage crossing control parameters.

[0178] In the embodiment of the present invention, the voltage fault ride-through includes low voltage fault ride-through, the initial grid control parameters include a voltage coefficient of an initial active current, a current coefficient of an initial active current, an active current reference value, a voltage coefficient of an initial reactive current, a current coefficient of an initial reactive current, and a reactive current reference value, the converter current output model includes an active current output model and a reactive current output model, the initial current includes an initial active current and an initial reactive current, and the control current includes an output active current and an output reactive current;

[0179] The control current generating unit 12 is specifically used to generate the output active current during low voltage fault ride-through through an active current output model according to the voltage coefficient of the initial active current, the current coefficient of the initial active current, the active current reference value, the machine-end voltage amplitude and the initial active current; and to generate the output reactive current during low voltage fault ride-through through a reactive current output model according to the voltage coefficient of the initial reactive current, the current coefficient of the initial reactive current, the reactive current reference value, the machine-end voltage amplitude, the preset first voltage threshold and the initial reactive current.

[0180] In the embodiment of the present invention, the voltage fault ride-through includes high voltage fault ride-through, the initial grid control parameters include a voltage coefficient of an initial active current, a current coefficient of an initial active current, an active current reference value, a voltage coefficient of an initial reactive current, a current coefficient of an initial reactive current, and a reactive current reference value, the converter current output model includes an active current output model and a reactive current output model, the initial current includes an initial active current and an initial reactive current, and the control current includes an output active current and an output reactive current;

[0181] The control current generating unit 12 is specifically used to generate the output active current during high voltage fault ride-through through an active current output model according to the voltage coefficient of the initial active current, the current coefficient of the initial active current, the active current reference value, the machine-end voltage amplitude and the initial active current; and to generate the output reactive current during high voltage fault ride-through through a reactive current output model according to the voltage coefficient of the initial reactive current, the current coefficient of the initial reactive current, the reactive current reference value, the machine-end voltage amplitude, the preset second voltage threshold and the initial reactive current.

[0182] In the embodiment of the present invention, the device further includes: a first sensitivity generating unit 15 , a transient low voltage model building unit 16 , a second sensitivity generating unit 17 , a third sensitivity generating unit 18 and a transient overvoltage model building unit 19 .

[0183] The first sensitivity generating unit 15 is used to generate the voltage control parameter sensitivity during the low voltage fault ride-through period according to the initial grid control parameter and the initial voltage.

[0184] The transient low voltage model building unit 16 is used to build a transient low voltage analytical model according to the voltage control parameter sensitivity, initial grid control parameters and initial voltage during the low voltage fault ride-through period.

[0185] The second sensitivity generating unit 17 is used to generate the low voltage control parameter sensitivity during the high voltage fault ride-through period according to the initial power grid control parameter.

[0186] The third sensitivity generating unit 18 is used to generate a high voltage control parameter sensitivity during a high voltage fault ride-through period according to the initial grid control parameter and the initial voltage.

[0187] The transient overvoltage model construction unit 19 is used to construct a transient overvoltage analytical model according to the low voltage control parameter sensitivity during the high voltage fault ride-through period, the high voltage control parameter sensitivity during the high voltage fault ride-through period, the initial grid control parameters and the initial voltage.

[0188] In the embodiment of the present invention, the optimal converter voltage ride-through control parameter includes an optimal transient undervoltage control parameter and an optimal transient overvoltage control parameter;

[0189] The control parameter solving unit 14 is specifically used to solve the transient low voltage analytical model through transient voltage constraints, current limit constraints and initial voltage, generate optimal transient low voltage control parameters, and perform reactive compensation control of the converter according to the optimal transient low voltage control parameters; solve the transient overvoltage analytical model through transient voltage constraints, current limit constraints and initial voltage, generate optimal transient overvoltage control parameters, and perform reactive compensation control of the converter according to the optimal transient overvoltage control parameters.

[0190] In the scheme of the embodiment of the present invention, the initial grid control parameters, machine-end voltage amplitude, initial current, initial voltage and transient voltage amplitude during voltage fault ride-through are obtained; the control current is generated according to the initial grid control parameters, the machine-end voltage amplitude and the initial current through a pre-constructed converter current output model; transient voltage constraints and current limit constraints are constructed according to the control current and the transient voltage amplitude through preset grid limits; according to the transient voltage constraints, the current limit constraints and the initial voltage, the constructed transient low voltage analytical model and transient overvoltage analytical model are solved to generate optimal converter voltage ride-through control parameters, and the converter reactive power compensation control is performed according to the optimal converter voltage ride-through control parameters, and the control parameters are optimized in the original optimization program to avoid the system transient voltage exceeding the limit, thereby satisfying the transient voltage stability during the voltage fault ride-through process.

[0191] The systems, devices, modules or units described in the above embodiments may be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer device, and specifically, the computer device may be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.

[0192] An embodiment of the present invention provides a computer device, including a memory and a processor, the memory is used to store information including program instructions, the processor is used to control the execution of the program instructions, and when the program instructions are loaded and executed by the processor, the steps of the embodiment of the above-mentioned converter reactive compensation control method during fault crossing are implemented. For a specific description, please refer to the embodiment of the above-mentioned converter reactive compensation control method during fault crossing.

[0193] Reference below Figure 4 , which shows a schematic diagram of the structure of a computer device 600 suitable for implementing an embodiment of the present application.

[0194] like Figure 4 As shown, the computer device 600 includes a central processing unit (CPU) 601, which can perform various appropriate operations and processes according to a program stored in a read-only memory (ROM) 602 or a program loaded from a storage part 608 into a random access memory (RAM) 603. In the RAM 603, various programs and data required for the operation of the computer device 600 are also stored. The CPU 601, the ROM 602, and the RAM 603 are connected to each other via a bus 604. An input / output (I / O) interface 605 is also connected to the bus 604.

[0195] The following components are connected to the I / O interface 605: an input section 606 including a keyboard, a mouse, etc.; an output section 607 including a cathode ray tube (CRT), a liquid crystal feedback device (LCD), etc., and a speaker, etc.; a storage section 608 including a hard disk, etc.; and a communication section 609 including a network interface card such as a LAN card, a modem, etc. The communication section 609 performs communication processing via a network such as the Internet. A drive 610 is also connected to the I / O interface 605 as needed. A removable medium 611, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 610 as needed, so that a computer program read therefrom is installed as needed as the storage section 608.

[0196] In particular, according to an embodiment of the present invention, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present invention includes a computer program product, which includes a computer program tangibly contained on a machine-readable medium, and the computer program includes program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through the communication part 609, and / or installed from the removable medium 611.

[0197] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0198] For the convenience of description, the above device is described in various units according to their functions. Of course, when implementing the present application, the functions of each unit can be implemented in the same or multiple software and / or hardware.

[0199] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0200] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0201] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0202] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0203] The acquisition, storage, use, and processing of data in the technical solution of this application comply with the relevant provisions of national laws and regulations.

[0204] It should be noted that in the embodiments of the present application, certain software, components, models and other existing solutions in the industry may be mentioned, and they should be regarded as exemplary. Their purpose is only to illustrate the feasibility of implementing the technical solution of the present application, but it does not mean that the applicant has or will necessarily use the solution.

[0205] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0206] The present application may be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The present application may also be practiced in distributed computing environments where tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules may be located in local and remote computer storage media, including storage devices.

[0207] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0208] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A method for controlling reactive power compensation of a converter during fault ride-through, characterized in that: The method comprises: Obtaining initial grid control parameters, terminal voltage amplitude, initial current, initial voltage and transient voltage amplitude during voltage fault ride-through; Generate a control current according to the initial grid control parameters, the machine-end voltage amplitude and the initial current through a pre-constructed converter current output model; By means of preset grid limits, according to the control current and transient voltage amplitude, transient voltage constraint conditions and current amplitude limit constraint conditions are constructed; According to the transient voltage constraint conditions, current limit constraint conditions and initial voltage, the constructed transient low voltage analytical model and transient overvoltage analytical model are solved to generate optimal converter voltage ride-through control parameters, and converter reactive power compensation control is performed according to the optimal converter voltage ride-through control parameters.

2. The method for controlling reactive power compensation of a converter during fault ride-through according to claim 1, characterized in that: The voltage fault ride-through includes low voltage fault ride-through, the initial grid control parameters include a voltage coefficient of an initial active current, a current coefficient of an initial active current, an active current reference value, a voltage coefficient of an initial reactive current, a current coefficient of an initial reactive current, and a reactive current reference value, the converter current output model includes an active current output model and a reactive current output model, the initial current includes an initial active current and an initial reactive current, and the control current includes an output active current and an output reactive current; The pre-built converter current output model is used to generate the control current according to the initial grid control parameters, the machine terminal voltage amplitude and the initial current, including: Generate an output active current during low voltage fault ride-through by using the active current output model according to the voltage coefficient of the initial active current, the current coefficient of the initial active current, the active current reference value, the machine-end voltage amplitude and the initial active current; Through the reactive current output model, the output reactive current during low voltage fault ride-through is generated according to the voltage coefficient of the initial reactive current, the current coefficient of the initial reactive current, the reactive current reference value, the machine-end voltage amplitude, the preset first voltage threshold and the initial reactive current.

3. The method for controlling reactive power compensation of a converter during fault ride-through according to claim 1, characterized in that: The voltage fault ride-through includes high voltage fault ride-through, the initial grid control parameters include a voltage coefficient of an initial active current, a current coefficient of an initial active current, an active current reference value, a voltage coefficient of an initial reactive current, a current coefficient of an initial reactive current, and a reactive current reference value, the converter current output model includes an active current output model and a reactive current output model, the initial current includes an initial active current and an initial reactive current, and the control current includes an output active current and an output reactive current; The pre-built converter current output model is used to generate the control current according to the initial grid control parameters, the machine terminal voltage amplitude and the initial current, including: Generate an output active current during high voltage fault ride-through by using the active current output model according to the voltage coefficient of the initial active current, the current coefficient of the initial active current, the active current reference value, the machine-end voltage amplitude and the initial active current; Through the reactive current output model, the output reactive current during high voltage fault riding is generated according to the voltage coefficient of the initial reactive current, the current coefficient of the initial reactive current, the reactive current reference value, the machine-end voltage amplitude, the preset second voltage threshold and the initial reactive current.

4. The method for controlling reactive power compensation of a converter during fault ride-through according to claim 1, characterized in that: The method further comprises: generating voltage control parameter sensitivity during low voltage fault ride-through according to initial grid control parameters and initial voltage; Constructing the transient low voltage analytical model according to the voltage control parameter sensitivity, initial grid control parameters and initial voltage during the low voltage fault ride-through period; generating low voltage control parameter sensitivity during high voltage fault ride-through according to the initial grid control parameters; generating a high voltage control parameter sensitivity during a high voltage fault ride-through period according to the initial grid control parameter and the initial voltage; The transient overvoltage analytical model is constructed according to the low voltage control parameter sensitivity during the high voltage fault ride-through, the high voltage control parameter sensitivity during the high voltage fault ride-through, the initial power grid control parameters and the initial voltage.

5. The method for controlling reactive power compensation of a converter during fault ride-through according to claim 1, characterized in that: The optimal converter voltage ride-through control parameters include optimal transient undervoltage control parameters and optimal transient overvoltage control parameters; The method of solving the constructed transient low voltage analytical model and transient overvoltage analytical model according to the transient voltage constraint condition, the current limit constraint condition and the initial voltage, generating optimal converter voltage ride-through control parameters, and performing converter reactive power compensation control according to the optimal converter voltage ride-through control parameters includes: Solving the transient low voltage analytical model through the transient voltage constraint condition, the current limit constraint condition and the initial voltage, generating optimal transient low voltage control parameters, and performing converter reactive power compensation control according to the optimal transient low voltage control parameters; The transient overvoltage analytical model is solved by the transient voltage constraint condition, the current limit constraint condition and the initial voltage to generate the optimal transient overvoltage control parameters, and the converter reactive power compensation control is performed according to the optimal transient overvoltage control parameters.

6. A converter reactive power compensation control device during fault ride-through, characterized in that: The device comprises: An acquisition unit, used to acquire initial grid control parameters, terminal voltage amplitude, initial current, initial voltage and transient voltage amplitude during voltage fault ride-through; A control current generating unit, configured to generate a control current according to the initial grid control parameters, the machine terminal voltage amplitude and the initial current through a pre-built converter current output model; A constraint condition generating unit, configured to construct a transient voltage constraint condition and a current limit constraint condition according to the control current and the transient voltage amplitude through a preset grid limit value; A control parameter solving unit is used to solve the constructed transient low voltage analytical model and transient overvoltage analytical model according to the transient voltage constraint condition, the current limit constraint condition and the initial voltage, generate optimal converter voltage ride-through control parameters, and perform converter reactive power compensation control according to the optimal converter voltage ride-through control parameters.

7. The converter reactive power compensation control device during fault ride-through according to claim 6, characterized in that: The voltage fault ride-through includes low voltage fault ride-through, the initial grid control parameters include a voltage coefficient of an initial active current, a current coefficient of an initial active current, an active current reference value, a voltage coefficient of an initial reactive current, a current coefficient of an initial reactive current, and a reactive current reference value, the converter current output model includes an active current output model and a reactive current output model, the initial current includes an initial active current and an initial reactive current, and the control current includes an output active current and an output reactive current; The control current generating unit is specifically used to generate the output active current during low voltage fault ride-through through the active current output model according to the voltage coefficient of the initial active current, the current coefficient of the initial active current, the active current reference value, the machine-end voltage amplitude and the initial active current; and to generate the output reactive current during low voltage fault ride-through through the reactive current output model according to the voltage coefficient of the initial reactive current, the current coefficient of the initial reactive current, the reactive current reference value, the machine-end voltage amplitude, the preset first voltage threshold and the initial reactive current.

8. The converter reactive power compensation control device during fault ride-through according to claim 6, characterized in that: The voltage fault ride-through includes high voltage fault ride-through, the initial grid control parameters include a voltage coefficient of an initial active current, a current coefficient of an initial active current, an active current reference value, a voltage coefficient of an initial reactive current, a current coefficient of an initial reactive current, and a reactive current reference value, the converter current output model includes an active current output model and a reactive current output model, the initial current includes an initial active current and an initial reactive current, and the control current includes an output active current and an output reactive current; The control current generating unit is specifically used to generate the output active current during high voltage fault ride-through through the active current output model according to the voltage coefficient of the initial active current, the current coefficient of the initial active current, the active current reference value, the machine-end voltage amplitude and the initial active current; and to generate the output reactive current during high voltage fault ride-through through the reactive current output model according to the voltage coefficient of the initial reactive current, the current coefficient of the initial reactive current, the reactive current reference value, the machine-end voltage amplitude, the preset second voltage threshold and the initial reactive current.

9. The converter reactive power compensation control device during fault ride-through according to claim 6, characterized in that: The device also includes: A first sensitivity generating unit, configured to generate a voltage control parameter sensitivity during a low voltage fault ride-through period according to an initial grid control parameter and an initial voltage; A transient low voltage model building unit, configured to build the transient low voltage analytical model according to the voltage control parameter sensitivity, the initial grid control parameter and the initial voltage during the low voltage fault ride-through period; A second sensitivity generating unit, configured to generate a low voltage control parameter sensitivity during a high voltage fault ride-through period according to an initial power grid control parameter; A third sensitivity generating unit, configured to generate a high voltage control parameter sensitivity during a high voltage fault ride-through period according to the initial grid control parameter and the initial voltage; The transient overvoltage model construction unit is used to construct the transient overvoltage analytical model according to the low voltage control parameter sensitivity during the high voltage fault ride-through, the high voltage control parameter sensitivity during the high voltage fault ride-through, the initial grid control parameters and the initial voltage.

10. The converter reactive power compensation control device during fault ride-through according to claim 6, characterized in that: The optimal converter voltage ride-through control parameters include optimal transient undervoltage control parameters and optimal transient overvoltage control parameters; The control parameter solving unit is specifically used to solve the transient low voltage analytical model through the transient voltage constraint condition, the current limit constraint condition and the initial voltage, generate the optimal transient low voltage control parameter, and perform the reactive compensation control of the converter according to the optimal transient low voltage control parameter; solve the transient overvoltage analytical model through the transient voltage constraint condition, the current limit constraint condition and the initial voltage, generate the optimal transient overvoltage control parameter, and perform the reactive compensation control of the converter according to the optimal transient overvoltage control parameter.

11. A computer readable medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method for controlling reactive power compensation of a converter during fault ride-through as described in any one of claims 1 to 5 is implemented.

12. A computer device comprising a memory and a processor, wherein the memory is used to store information including program instructions, and the processor is used to control the execution of the program instructions, characterized in that: When the program instructions are loaded and executed by the processor, the method for controlling reactive power compensation of a converter during fault ride-through as described in any one of claims 1 to 5 is implemented.

13. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by a processor, the method for controlling reactive power compensation of a converter during fault ride-through as claimed in any one of claims 1 to 5 is implemented.

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