A method and device for controlling reactive power compensation of a converter during fault ride-through

Abstract

The present invention provides a method and device for controlling reactive compensation of a converter during fault ride-through, the method comprising: generating a control current according to initial grid control parameters, a machine-end voltage amplitude and an initial current through a pre-constructed converter current output model; constructing transient voltage constraints and current limit constraints according to the control current and the transient voltage amplitude through preset grid limits; solving the constructed transient undervoltage analytical model and transient overvoltage analytical model according to the transient voltage constraints, the current limit constraints and the initial voltage, generating optimal converter voltage ride-through control parameters, and performing converter reactive compensation control according to the optimal converter voltage ride-through control parameters, realizing optimization of the control parameters in the original optimization program, avoiding system transient voltage exceeding the limit, and thereby satisfying transient voltage stability during the voltage fault ride-through process.

Description

Technical Field

[0001] The present invention relates to the field of 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 equipment 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 power supply on the system voltage stability in the key stages of the transient process based on the transient characteristics of the asynchronous 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 existing technology, voltage fault ride-through usually limits the current generated by the converter during the fault to prevent the converter from 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 power supply that is 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 requirements 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, optimizing control parameters within an existing optimization program to avoid system transient voltage exceeding limits, thereby ensuring transient voltage stability during voltage fault ride-through. Another object of the present invention is to provide an apparatus 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. Yet 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 a fault ride-through period, 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 using 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 pre-built converter current output model generates the control current based on the initial grid control parameters, the terminal voltage amplitude, and the initial current, including:

[0011] The active current output model generates the output active current during the low voltage fault ride-through period 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 the low voltage fault ride-through period 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 terminal 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 pre-built converter current output model generates the control current based on 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 using the active current output model based on 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;

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

[0020] generating low voltage control parameter sensitivities during high voltage fault ride-through based on 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] Based on the transient voltage constraints, current limit constraints, and initial voltage, the constructed transient undervoltage and transient overvoltage analytical models are solved to generate the optimal converter voltage ride-through control parameters. The converter reactive power compensation control is then performed according to the optimal converter voltage ride-through control parameters, including:

[0025] The transient low voltage analytical model is solved by using transient voltage constraints, current limit constraints, and initial voltage to generate optimal transient low voltage control parameters. Converter reactive power compensation control is then performed according to the optimal transient low voltage control parameters.

[0026] The transient overvoltage analytical model is solved by transient voltage constraints, current limit constraints and initial voltage to generate optimal transient overvoltage control parameters. 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, configured 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 is used to generate a control current according to the initial grid control parameters, the terminal voltage amplitude and the initial current by using a pre-built converter current output model;

[0030] A constraint condition generating unit is used to construct a transient voltage constraint condition and a current limit constraint condition according to the control current and transient voltage amplitude through a preset grid limit value;

[0031] The control parameter solving unit is used to solve the constructed transient undervoltage analytical model and transient overvoltage analytical model according to the transient voltage constraint conditions, current limit constraint conditions and 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 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.

[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 generation 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.

[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 is used to build a transient low voltage analytical model based on 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 based on the initial 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 construction unit is used to construct a transient overvoltage analytical model based on 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.

[0042] Preferably, the optimal converter voltage ride-through control parameters include optimal transient undervoltage control parameters and optimal transient overvoltage control parameters;

[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 converter reactive compensation control 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 converter reactive compensation control 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, comprising a computer program / instruction, which implements the above method 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 the 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 the control current and transient voltage amplitude through preset grid limits; solves the constructed transient undervoltage analytical model and transient overvoltage analytical model according to the 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 following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any 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 structural diagram of a computer device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0053] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0054] It should be noted that the method and device for controlling reactive power compensation 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 other than the field of artificial intelligence technology. The application field of the method and device for controlling reactive power compensation 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 this application, the relevant contents of the technical solution of this 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 have caused the system to lack synchronous support, and the strength and voltage support capacity of the power grid have declined. It generally presents 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 fault occurs in the power grid, 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, 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 transient voltage stability during the voltage fault ride-through process.

[0057] The following describes the implementation of the method for controlling reactive power compensation during a fault ride-through period provided by an embodiment of the present invention, using a converter reactive power compensation control device during a fault ride-through period as an example. It is understood that the method for controlling reactive power compensation during a fault ride-through period provided by an embodiment of the present invention may include, but is not limited to, the converter reactive power compensation control device during a fault ride-through period.

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

[0059] Step 101: Acquire 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 using 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, and 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 the initial active current and the initial reactive current, and the control current includes the output active current and the 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 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, the converter current output model includes an active current output model and a reactive current output model, the initial current includes the initial active current and the initial reactive current, and the control current includes the output active current and the output reactive current.

[0063] Step 103: 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.

[0064] Step 104: Solve the constructed transient undervoltage analytical model and transient overvoltage analytical model according to the transient voltage constraint, the current limit constraint, 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 period 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; the transient voltage constraint conditions and the current limit constraint conditions are constructed according to the control current and the transient voltage amplitude through preset grid limits; the constructed transient undervoltage analysis model and the transient overvoltage analysis model are solved according to the transient voltage constraint conditions, the current limit constraint conditions and the initial voltage, and the optimal converter voltage ride-through control parameters are generated, 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.

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

[0068] Step 201: Acquire 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 the fault ride-through period.

[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 using a pre-built converter current output model according to initial grid control parameters, the machine-end voltage amplitude, and the initial current.

[0072] After a power grid fault occurs, 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 ride-through process to maintain transient voltage stability. When a system fault occurs, the converter enters the low voltage ride-through (LVRT) phase, at which time the output current needs to be controlled. Constructing a converter current output model can better control the converter output.

[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 terminal 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 period.

[0079] Step 2022: Generate the output reactive current during the low voltage fault ride-through period 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 terminal voltage amplitude, the preset first voltage threshold and the initial reactive current.

[0080] The reactive current output model of the converter during LVRT is assumed to be:

[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 period.

[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 shows that when the grid voltage drops significantly, the control strategy makes the active current component I p,LVRT Drop, reactive current component I q,LVRT This control strategy increases the voltage support provided by the PV converter compared to an uncontrolled state, thereby providing additional voltage support for the 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 ride through (HVRT) phase. At this time, a converter current output model during the HVRT period is constructed.

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

[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 terminal 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 period.

[0092] Step 3022: Generate the output reactive current during the HVRT period 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 terminal 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 period.

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

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

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

[0099] In an embodiment of the present invention, after constructing a converter output current model that includes various control parameters, to achieve the goal of controlling transient voltages and enhancing voltage stability, it is necessary to determine the values ​​of the control parameters based on the degree to which the transient voltage amplitude is affected by each control parameter. In power systems, the degree of transient voltage influence can be measured by calculating the sensitivity of the transient voltage 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 is 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 of the variable.

[0106] LVRT transient voltage V pv,LV Relative to the 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 the 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 is the variable reactive current reference value curve.

[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 based on 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, based on the LVRT voltage coefficient, LVRT reactive current coefficient, LVRT reactive current reference value, LVRT initial voltage and their corresponding sensitivities, 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 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 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 the LVRT reactive current reference value I qset,LV 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 period.

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

[0118] Step 205: Generate low voltage control parameter sensitivity during high voltage fault ride-through according to the initial 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 LVRT reactive current control parameter.

[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 is 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 of the variable.

[0126] HVRT transient voltage V pv,LV Relative to the 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 the 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 is the variable reactive current reference value curve.

[0129] Step 206: Generate high voltage control parameter sensitivity during high voltage fault ride-through 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 of 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 is the variable reactive current reference value curve.

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

[0145] Specifically, based on the LVRT voltage coefficient, LVRT reactive current coefficient, LVRT reactive current reference value during the HVRT period and their corresponding low voltage control parameter sensitivity during the HVRT period, 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 the HVRT period, 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 Track 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 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 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 the LVRT reactive current reference value I qset,LV 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 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 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 Trajectory sensitivity, I qset,HV It is the reactive current reference value during HVRT period.

[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 this embodiment of the present invention, when solving power system stability problems, transient voltage stability is rewritten as an inequality constraint to facilitate optimization calculations. Based on the constructed analytical models for transient undervoltage and transient overvoltage, transient voltage constraints are 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 limits include the minimum voltage limit specified during the LVRT process for maintaining equipment operation, the maximum voltage limit specified during the HVRT process for maintaining equipment operation, the maximum limit of the converter output current during the LVRT process, and the maximum limit of the converter output current during the HVRT process.

[0153] Specifically, transient voltage constraints are constructed based on the transient voltage amplitude, the minimum voltage limit for equipment operation specified during LVRT, and the maximum voltage limit for equipment operation specified during HVRT:

[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 controlled current includes the output active current during the LVRT period, the output reactive current during the LVRT period, the output active current during the HVRT period, and the output reactive current during the HVRT period.

[0159] In the voltage ride-through phase, 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 based on the transient voltage constraint, the current limit constraint and the initial voltage to 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, namely: the converter reactive power compensation control strategy, are obtained 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 an LVRT voltage coefficient, an LVRT reactive current coefficient, an LVRT reactive current reference value, and an LVRT initial voltage.

[0166] Step 210: Solve the transient overvoltage analytical model based on the transient voltage constraint, the current limit constraint and the initial voltage to 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, namely: the converter reactive power compensation control strategy, are obtained, thereby ensuring 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 the HVRT period.

[0169] It is worth noting that the acquisition, storage, use, and processing of data in the technical solutions 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 converter reactive compensation control method during fault ride-through provided by an 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; 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 undervoltage 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 structural diagram of a converter reactive compensation control device during a fault ride-through period provided by an embodiment of the present invention, wherein the device is used to execute the converter reactive compensation control method during the fault ride-through period. 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 terminal 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 terminal voltage amplitude and the initial current through a pre-built converter current output model.

[0176] The constraint condition generating unit 13 is used to construct a transient voltage constraint condition and a current limit constraint condition 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 undervoltage 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.

[0178] In an 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 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.

[0180] In an 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 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.

[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 configured to generate a voltage control parameter sensitivity during a 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, the initial grid control parameters and the initial voltage during the low voltage fault ride-through period.

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

[0186] The third sensitivity generating unit 18 is 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.

[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 converter reactive compensation control 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 converter reactive compensation control according to the optimal transient overvoltage control parameters.

[0190] In the scheme of 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 period 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; the transient voltage constraint conditions and the current limit constraint conditions are constructed according to the control current and the transient voltage amplitude through preset grid limits; the constructed transient undervoltage analysis model and the transient overvoltage analysis model are solved according to the transient voltage constraint conditions, the current limit constraint conditions and the initial voltage, and the optimal converter voltage ride-through control parameters are generated, 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 having certain functions. A typical implementation device is a computer device. Specifically, the computer device may be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smartphone, 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 being used to store information including program instructions, the processor being used to control the execution of the program instructions, and the program instructions being loaded and executed by the processor to implement the various steps of the embodiment of the above-mentioned method for controlling reactive compensation of the converter during fault crossing. For a specific description, please refer to the embodiment of the above-mentioned method for controlling reactive compensation of the converter during fault crossing.

[0193] Reference below Figure 4 , which shows a structural diagram 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 tasks and processes according to a program stored in a read-only memory (ROM) 602 or a program loaded from a storage portion 608 into a random access memory (RAM) 603. Various programs and data required for the operation of the computer device 600 are also stored in the RAM 603. The CPU 601, ROM 602, and 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, and the like; an output section 607 including devices such as a cathode ray tube (CRT), a liquid crystal display (LCD), and a speaker; a storage section 608 including devices such as a hard disk; and a communication section 609 including a network interface card such as a LAN card or a modem. 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. Removable media 611, such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory, is installed in the drive 610 as needed, so that computer programs read therefrom can be installed in the storage section 608 as needed.

[0196] In particular, according to embodiments of the present invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the present invention include a computer program product comprising a computer program tangibly embodied on a machine-readable medium, the computer program including program code for executing the methods illustrated in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via communication portion 609 and / or installed from removable media 611.

[0197] Computer-readable media includes permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. The 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 disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, magnetic 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 transitory computer-readable media (transitory media), such as modulated data signals and carrier waves.

[0198] For the convenience of description, the above devices are described as being divided into various units according to their functions. Of course, when implementing this 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 flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, 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 flowcharts and / or block diagrams. 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 that can direct a computer or other programmable data processing device to work 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 The 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 operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0202] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0203] The acquisition, storage, use, and processing of data in this application's technical solution comply with relevant 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. 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 take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing 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 communications network. In a distributed computing environment, program modules may be located in local and remote computer storage media, including storage devices.

[0207] The various embodiments in this specification are described in a progressive manner. Similar parts between the various embodiments can be referred to in conjunction with each other. Each embodiment focuses on the differences between the other embodiments. In particular, the system embodiments are generally similar to the method embodiments, so the description is relatively simple. For relevant parts, refer to the description of the method embodiments.

[0208] The foregoing is merely 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 modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within 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 terminal voltage amplitude and the initial current using a pre-built converter current output model; generating voltage control parameter sensitivity during low voltage fault ride-through according to initial grid control parameters and initial voltage; Constructing a transient low voltage analytical model based on 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 sensitivities during high voltage fault ride-through based on initial grid control parameters; generating a high voltage control parameter sensitivity during a high voltage fault ride-through period based on the initial grid control parameter and the initial voltage; Constructing a transient overvoltage analytical model based on 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; By using preset grid limits, according to the control current and transient voltage amplitude, constructing transient voltage constraint conditions and current limit constraint conditions; 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 optimal converter voltage ride-through control parameters. The optimal converter voltage ride-through control parameters include optimal transient low voltage control parameters and optimal transient overvoltage control parameters. Converter reactive power compensation control is performed according to the optimal transient low voltage control parameters, and converter reactive power compensation control is performed according to the optimal transient overvoltage control parameters.

2. The method for controlling converter reactive power compensation during fault ride-through according to claim 1, wherein: The voltage fault ride-through includes low voltage fault ride-through, the initial grid control parameters include a voltage coefficient of the initial active current, a current coefficient of the initial active current, an active current reference value, a voltage coefficient of the initial reactive current, a current coefficient of the 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 method of generating a control current by using a pre-built converter current output model according to the initial grid control parameters, the terminal voltage amplitude, and the initial current includes: Generate an output active current during low voltage fault ride-through by using the active current output model, based on 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; 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 converter reactive power compensation during fault ride-through according to claim 1, wherein: The voltage fault ride-through includes high voltage fault ride-through, the initial grid control parameters include a voltage coefficient of the initial active current, a current coefficient of the initial active current, an active current reference value, a voltage coefficient of the initial reactive current, a current coefficient of the 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 method of generating a control current by using a pre-built converter current output model according to the initial grid control parameters, the terminal voltage amplitude, and the initial current includes: Generate an output active current during high voltage fault ride-through by using the active current output model, based on 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; 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.

4. A converter reactive power compensation control device during fault ride-through, characterized in that: The method for controlling reactive power compensation of a converter during a fault ride-through period according to any one of claims 1 to 3, the device comprising: an acquisition unit, configured 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 terminal voltage amplitude and the initial current using 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 by using a preset grid limit value; A control parameter solving unit is used to solve the constructed transient undervoltage 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 compensation control according to the optimal converter voltage ride-through control parameters.

5. The converter reactive power compensation control device during fault ride-through according to claim 4, characterized in that: The voltage fault ride-through includes low voltage fault ride-through, the initial grid control parameters include a voltage coefficient of the initial active current, a current coefficient of the initial active current, an active current reference value, a voltage coefficient of the initial reactive current, a current coefficient of the 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.

6. The converter reactive power compensation control device during fault ride-through according to claim 4, characterized in that: The voltage fault ride-through includes high voltage fault ride-through, the initial grid control parameters include a voltage coefficient of the initial active current, a current coefficient of the initial active current, an active current reference value, a voltage coefficient of the initial reactive current, a current coefficient of the 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.

7. The converter reactive power compensation control device during fault ride-through according to claim 4, characterized in that: The device further comprises: 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 construction unit, configured to construct 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; a second sensitivity generating unit, configured to generate a low voltage control parameter sensitivity during a high voltage fault ride-through period based on the initial 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 period, the high voltage control parameter sensitivity during the high voltage fault ride-through period, the initial grid control parameters and the initial voltage.

8. The converter reactive power compensation control device during fault ride-through according to claim 4, 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.

9. 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 according to any one of claims 1 to 3 is implemented.

10. 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, wherein: When the program instructions are loaded and executed by the processor, the method for controlling reactive power compensation of the converter during fault ride-through according to any one of claims 1 to 3 is implemented.

11. 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 according to any one of claims 1 to 3 is implemented.

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