Fault Ride-Through Method, System, Electronic Device and Storage Medium for New Energy Access to Converter Station

Abstract

The present invention provides a fault ride-through method, system, electronic device and storage medium for new energy accessing a converter station, belonging to the field of flexible DC power transmission in a power system. The method includes: detecting faults of a new energy power station and a sending-end converter station, and obtaining fault information after detecting the occurrence of a fault; calculating control instructions for the new energy power station and the sending-end converter station based on the fault information; and transmitting the control instructions to the new energy power station and the sending-end converter station to achieve fault ride-through control. An equivalent fault model for the new energy power station and the sending-end converter station is proposed, which makes full use of the flexible control and coordination capabilities of the two types of converters, is beneficial to improving the grid connection performance of the new energy flexible DC island system under faults, and when a fault occurs in the sending-end AC collection line, the new energy power station and the sending-end converter station are controlled through control instructions, greatly reducing the active power deficit caused by the sending-end fault to the onshore power grid. The operation constraints of the new energy power station and the converter station are fully considered to ensure their operation safety under faults.

Description

Technical Field

[0001] The present invention belongs to the technical field of flexible DC power transmission in power systems, and particularly relates to a fault ride-through method, system, electronic device and storage medium for new energy access to a converter station. Background Art

[0002] Wind power, photovoltaic power, etc., as clean and renewable energy sources, are of great significance for promoting the transformation of the global energy structure. Flexible DC power transmission technology is an important solution for realizing the long-distance transmission of new energy. When a fault occurs in the AC collection line at the new energy sending end, it is easy to cause active power to be sent back from the onshore power grid to the sending end system, and a large amount of active power deficit is generated in the onshore power grid during the fault process. Therefore, when a fault occurs in the sending end collection line, it is of great significance for the safe operation of the onshore power grid to maximize the transmission of new energy active power to the receiving end on the premise of ensuring the safety of the new energy converter and the sending end converter station itself.

[0003] The fault ride-through strategy proposed in the prior art. Replacing the traditional reactive power priority strategy of the unit with an active power priority strategy during a fault can make the AC voltage of the system easier to reach stability. Its disadvantages are: during a fault, the sending end converter station is still simply equivalent to a constant current source, its flexible control ability is not effectively utilized, and effective cooperation with the new energy power station cannot be achieved. The proposed method for reducing voltage and limiting current of the sending end flexible DC converter station. During a fault, the voltage is stepped down in segments according to the magnitude of the actual output current. Its disadvantages are: only the overcurrent problem of the converter station under severe fault conditions is concerned, and the problem of a large amount of reverse power flow of active power in the onshore power grid that generally occurs during a sending end fault cannot be solved. The proposed method for optimizing the design of the current parameters of the photovoltaic side inverter and the sending end converter station during a fault. The influence of the current setting values of the converters on both sides of the fault point on the DC voltage on the flexible DC side is analyzed through simulation. Its disadvantages are: no perfect theoretical analysis is carried out and the limitations of constraints such as the active power output of new energy are not considered.

[0004] In summary, the existing fault ride-through methods for the collection system of new energy access to a converter station do not effectively utilize the collaborative cooperation ability of the new energy converter and the sending end converter station, cannot fundamentally solve the problem of reverse power flow of active power in the onshore power grid, and do not comprehensively consider the limitations of the operation constraints of the new energy power station and the flexible DC converter station. Summary of the Invention

[0005] The purpose of the embodiments of the present invention is to provide a fault ride-through method, system, electronic device and storage medium for new energy access to a converter station, which are used to wholly or at least partially solve the technical problems existing in the above prior art, such as the failure to effectively utilize the collaborative cooperation ability of the new energy converter and the sending end converter station, the inability to fundamentally solve the problem of reverse power flow of active power in the onshore power grid, and the failure to comprehensively consider the limitations of the operation constraints of the new energy power station and the flexible DC converter station.

[0006] In a first aspect, an embodiment of the present application provides a fault ride-through method for a new energy access converter station, including:

[0007] Perform fault detection on the new energy power station and the sending-end converter station, and obtain fault information after detecting the occurrence of a fault;

[0008] Based on the fault information, calculate the control commands for the new energy power station and the sending-end converter station;

[0009] Transmit the control commands to the new energy power station and the sending-end converter station to achieve fault ride-through control.

[0010] Optionally, before performing fault detection on the new energy power station and the sending-end converter station and obtaining fault information after detecting the occurrence of a fault, the fault ride-through method for the new energy access converter station further includes: establishing a fault equivalent model for the new energy power station and the sending-end converter station:

[0011] Equivalently represent the new energy power station and the sending-end converter station as a controlled current source and a controlled voltage source respectively, where the effective value and phase angle of the current output by the controlled current source are the controlled quantities, and the effective value of the voltage output by the controlled voltage source is the controlled quantity.

[0012] Optionally, based on the fault information, calculating the control commands for the new energy power station and the sending-end converter station includes:

[0013] Based on the fault information, calculate the effective value of the current of the sending-end converter station, the output voltage of the sending-end converter station, and the output active power of the new energy power station when controlling according to the theoretical optimal values of the controlled quantities of the general new energy power station and the sending-end converter station respectively;

[0014] Judge whether the effective value of the current of the sending-end converter station, the output voltage of the sending-end converter station, and the output active power of the new energy power station exceed the limit. If so, use the theoretical optimal values of the controlled quantities of the general new energy power station and the sending-end converter station as the initial guess points, solve the reference values of each controlled quantity through nonlinear programming, and use the solved reference values of each controlled quantity as the control commands; if not, use the theoretical optimal values of the controlled quantities of the general new energy power station and the sending-end converter station as the reference values of the controlled quantities and use the reference values of the controlled quantities as the control commands.

[0015] Optionally, the theoretical optimal values of the controlled quantities of the general new energy power station and the sending-end converter station are characterized as:

[0016]

[0017] In the formula, w1 represents the new energy power station on the fault branch, and wi represents the new energy power stations on the non-fault branches, I wimax is the i maximum output current of the R fis the fault resistance, X t is the leakage inductance of the connecting transformer, X 0 is the equivalent reactance from the fault point to the PCC point, R = R f + R 0 is the total fault resistance, X = X t + X 0 * represents the theoretical optimal value without considering other constraints, U M is the output voltage of the sending - end converter station, θ wi is the phase of the output current of the new - energy power station.

[0018] Optionally, according to the following formula, based on the fault information, calculate the effective value of the current of the sending - end converter station when controlling according to the theoretical optimal values of the controlled variables of the general new - energy power station and the sending - end converter station:

[0019] ;

[0020] ;

[0021] ;

[0022] In the formula, R f is the fault resistance, I wimax is the maximum output current of the i th power station, X 0 is the equivalent reactance from the fault point to the PCC point.

[0023] Optionally, according to the following formula, based on the fault information, calculate the output voltage of the sending - end converter station when controlling according to the theoretical optimal values of the controlled variables of the general new - energy power station and the sending - end converter station:

[0024] ;

[0025] In the formula, R f is the fault resistance, I wimax is the maximum output current of the i th power station, X 0 is the equivalent reactance from the fault point to the PCC point, X t is the leakage inductance of the connecting transformer.

[0026] Optionally, according to the following formula, based on the fault information, calculate the active power output of the new - energy power station when controlling according to the theoretical optimal values of the controlled variables of the general new - energy power station and the sending - end converter station:

[0027]

[0028] Wherein, and are the active powers output by the new energy power stations on the faulty branch and the non-faulty branch respectively, R i and X i represent the equivalent resistance and reactance from the outlet of the new energy power station on the i th non-faulty branch to the PCC point, R f is the fault resistance, R0 and X0 are the equivalent resistance and reactance from the fault point to the PCC point respectively.

[0029] In a second aspect, an embodiment of the present application further provides a fault ride-through system for new energy access to a converter station, including:

[0030] An acquisition unit, configured to detect faults of the new energy power station and the sending-end converter station, and acquire fault information after detecting the occurrence of a fault;

[0031] A calculation unit, configured to calculate control instructions for the new energy power station and the sending-end converter station based on the fault information;

[0032] A control unit, configured to transmit the control instructions to the new energy power station and the sending-end converter station to implement fault ride-through control.

[0033] In a third aspect, an embodiment of the present application further provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, the steps of the above-mentioned fault ride-through method for new energy access to a converter station are implemented.

[0034] In a fourth aspect, an embodiment of the present application further provides a storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the above-mentioned fault ride-through method for new energy access to a converter station are implemented.

[0035] It can be seen from the above technical solutions that the present invention has the following advantages:

[0036] In the fault ride-through method, system, electronic device, and storage medium for new energy access to a converter station provided by the present application, an equivalent fault model for the new energy power station and the sending-end converter station is proposed, which makes full use of the flexible control and cooperation capabilities of the two types of converters, is beneficial to improving the grid connection performance of the new energy HVDC island system under faults, and when any degree of fault occurs in the sending-end AC collection line, by controlling the new energy power station and the sending-end converter station through control instructions, the active power deficit caused by the sending-end fault to the onshore power grid is greatly reduced, and the operation constraints of the new energy power station and the converter station are fully considered to ensure its operation safety under faults. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the present invention, the drawings required for description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0038] Figure 1 It is a flowchart of a fault ride-through method for a new energy access converter station provided by an embodiment of the present invention;

[0039] Figure 2 It is a typical topology diagram of a new energy grid-connected system via a flexible DC transmission provided by an embodiment of the present invention;

[0040] Figure 3 It is an equivalent model of system fault ride-through provided by an embodiment of the present invention;

[0041] Figure 4 It is a detailed flowchart of a fault ride-through method for a new energy access converter station provided by an embodiment of the present invention;

[0042] Figure 5 It is a schematic structural diagram of a fault ride-through system for a new energy access converter station provided by an embodiment of the present invention;

[0043] Figure 6 It is a schematic hardware structure diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0044] In the following detailed description, various embodiments of the present disclosure will be described more fully. The present disclosure can have various embodiments, and adjustments and changes can be made therein. However, it should be understood that there is no intention to limit the various embodiments of the present disclosure to the specific embodiments disclosed herein, but the present disclosure should be understood to cover all adjustments, equivalents, and / or alternative solutions that fall within the spirit and scope of the various embodiments of the present disclosure.

[0045] In the following text, the term "comprising" or "may comprise" used in various embodiments of the present disclosure indicates the presence of the disclosed functions or operations, and does not limit the addition of one or more functions or operations. In addition, as used in various embodiments of the present disclosure, the terms "comprising", "having" and their cognates are only intended to indicate the presence of specific features, numbers, steps, operations or combinations of the foregoing items, and should not be understood as first excluding the existence or addition of the possibility of one or more other features, numbers, steps, operations or combinations of the foregoing items.

[0046] In various embodiments of the present disclosure, the expression "or" or "at least one of A or / and B" includes any combination or all combinations of the recited words. For example, the expression "A or B" or "at least one of A or / and B" may include A, may include B, or may include both A and B.

[0047] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0048] Refer to Figure 1 Shown is a flowchart of a fault ride-through method for a new energy access converter station in a specific embodiment, including the following execution steps:

[0049] Step 100: Perform fault detection on the new energy power station and the sending-end converter station, and obtain fault information after detecting the occurrence of a fault.

[0050] In some embodiments, before executing step 100, the following steps are also executed: The new energy power station and the sending-end converter station are respectively equivalent to a controlled current source and a controlled voltage source, where the effective value and phase angle of the current output by the controlled current source are controlled variables, and the effective value of the voltage output by the controlled voltage source is a controlled variable.

[0051] In some embodiments, the typical topology of the new energy connected to the flexible DC grid system is as Figure 2 Shown. Establishing a fault equivalent model of the new energy power station and the sending-end converter station is the basis for realizing fault ride-through control. The new energy power station and the sending-end converter station are respectively equivalent to a controlled current source and a controlled voltage source, where the effective value and phase angle of the current output by the current source, and the effective value of the voltage output by the voltage source are controlled variables. The system fault ride-through equivalent model is as Figure 3 Shown, where the effective value of the current output by the wind farm I wj And its phase θ wj ( j = 1, 2, 3... N ), the effective value of the voltage output by the offshore converter station U M Are controlled variables, and this model is the basis for realizing fault ride-through control.

[0052] Based on Figure 3 The fault equivalent model, the control objective of this application is: The active power output by the new energy power station is transmitted to the onshore power grid to the maximum extent (i.e., P M(maximum), the controlled variables are: the effective value of the output current of the new energy power station I wj and its phase θ wj ( j = 1, 2, 3… N ), the output voltage of the sending-end converter station U M . The following takes N = 2 as an example to derive the analytical expressions of each controlled quantity and give the general selection principle.

[0053] P M The expression of

[0054] (1)

[0055] In the formula, P M is the active power transmitted to the onshore power grid through the sending-end converter station; U M is the effective value of the controlled voltage of the sending-end converter station; I M is the effective value of the output current of the sending-end converter station; · represents the phasor form of the electrical quantity; — represents the conjugate symbol; Re represents taking the real part of the complex number.

[0056] The current flowing through the fault branch I 0 can be expressed as:

[0057] (2)

[0058] (3)

[0059] In the formula, I w2 is the effective value of the output current of power station 2; U f is the fault point voltage; U PCC is the voltage of the converter station AC outlet bus (PCC point); R 0 and X 0 are the equivalent resistance and reactance from the fault point to the PCC point respectively.

[0060] The fault point voltage and the PCC point voltage can be expressed as:

[0061] (4)

[0062] (5)

[0063] In the formula, I w1is the effective value of the output current of Substation 1; R f is the fault resistance; X t is the leakage inductance of the coupling transformer.

[0064] Combining equations (2) to (5) gives:

[0065] (6)

[0066] wherein, R = R f + R 0, X = X t + X 0.

[0067] Writing the phasors in equation (6) in trigonometric form, then

[0068] (7)

[0069] wherein,

[0070] (8)

[0071] (9)

[0072] wherein, θ 1 and θ 2 are the controlled phase angles of the output currents of Substation 1 and Substation 2, respectively.

[0073] Combining equations (1) and (7) gives:

[0074] (10)

[0075] When (11)

[0076] P M reaches the maximum: (12)

[0077] b is a fixed value under the fault ， For a , it should be made that I w1 、 I w2 as large as possible and satisfy:

[0078] (13)

[0079] Considering the influence of the output current limit of the new energy converter, the following can be taken:

[0080] (14)

[0081] At this time,

[0082] (15)

[0083] (16)

[0084] In the formula, I w1max and I w2max are respectively the maximum output currents of new energy power station 1 and power station 2, and * represents the theoretical optimal value without considering other constraints.

[0085] Step 101: Calculate the control commands of the new energy power station and the sending-end converter station based on the fault information.

[0086] Specifically, when executing step 101, the following steps can be specifically executed:

[0087] S1010: Based on the fault information, calculate the effective value of the current of the sending-end converter station, the output voltage of the sending-end converter station, and the output active power of the new energy power station when controlling according to the theoretical optimal values of the controlled variables of the general new energy power station and the sending-end converter station respectively.

[0088] Specifically, when the number of new energy power stations is N , the above idea can still be used for derivation, and the expressions of the theoretical optimal values of the controlled variables of the general new energy power station and the sending-end converter station can be obtained as:

[0089] (17)

[0090] In the formula, w1 represents the new energy power station on the fault branch, wi represents the new energy power stations on the non-fault branches, I wimax is the maximum output current of the i th power station, R f is the fault resistance, X t is the leakage inductance of the coupling transformer, X 0 is the equivalent reactance from the fault point to the PCC point, R = R f + R 0, is the total fault resistance, X = X t + X 0, * represents the theoretical optimal value without considering other constraints,U M is the output voltage of the sending - end converter station, θ wi is the output current phase of the new - energy power station.

[0091] The selection principles of the controlled variables are given above under the constraint of only considering the maximum output current of the new - energy power station. During actual operation, using Equation (17) as the control variable in some working conditions may cause other electrical quantities of the two - side converters to exceed the limit values. To ensure the safety of the device, the following additional constraints should also be considered:

[0092] By combining Equations (6), (14) and (15), the effective value of the phase current of the sending - end converter station can be obtained as:

[0093] (18)

[0094] where,

[0095] (19)

[0096] (20)

[0097] In the formula, R f is the fault resistance, I wimax is the maximum output current of the i - th power station, X0 is the equivalent reactance from the fault point to the PCC point.

[0098] It can be seen that when R is relatively small, there may be an over - current risk at the sending - end converter station, and its current constraint should be considered.

[0099] According to (15), when a high - resistance fault occurs, the optimal output voltage of the converter station can be approximated as:

[0100] (21)

[0101] U M is positively correlated with R f When the fault resistance is large, the output voltage may be greater than the rated value, which will cause over - voltage in the system. The voltage constraint of the sending - end converter station should be considered.

[0102] For new - energy power stations, the active power output by Power Station 1 and Power Station 2 can be expressed as

[0103] (22)

[0104] (23)

[0105] (24)

[0106] In the formula, R 1 and X 1 are the equivalent resistance and reactance from the outlet of the new energy power station on the faulty branch to the fault point respectively; R 2 and X 2 are the equivalent resistance and reactance from the outlet of the new energy power station on the non-faulty branch to the PCC point respectively.

[0107] The optimal active power of the new energy power station may be less than the actual available active power of the power station, and its active power constraint should be considered.

[0108] Extend the above constraints to N wind farms, and the effective value of the converter station current can be obtained:

[0109] (25)

[0110] (26)

[0111] (27)

[0112] In the formula, R f is the fault resistance, I wimax is the maximum output current of the i th power station, X 0 is the equivalent reactance from the fault point to the PCC point.

[0113] According to the following formula, based on the fault information, calculate the output voltage of the sending-end converter station when controlling according to the theoretical optimal values of the controlled variables of the general new energy power station and the sending-end converter station:

[0114] (28)

[0115] In the formula, R f is the fault resistance, I wimax is the maximum output current of the i th power station, X 0 is the equivalent reactance from the fault point to the PCC point, X t is the leakage inductance of the connecting transformer.

[0116] According to the following formula, based on the fault information, calculate the output active power of the new energy power station when controlling according to the theoretical optimal values of the controlled variables of the general new energy power station and the sending-end converter station:

[0117] (29)

[0118] (30)

[0119] (31)

[0120] In the formula, and are the active powers output by the new energy power stations on the faulty branch and the non-faulty branch respectively, R i and X i represent the equivalent resistance and reactance from the outlet of the new energy power station on the i th non-faulty branch to the PCC point, R f is the fault resistance, R 0 and X 0 are the equivalent resistance and reactance from the fault point to the PCC point respectively.

[0121] S1011: Determine whether the effective value of the current of the sending-end converter station, the output voltage of the sending-end converter station, and the output active power of the new energy power station exceed the limit. If so, use the theoretical optimal values of the controlled variables of the general new energy power station and the sending-end converter station as the initial guess points, solve the reference values of each controlled variable through nonlinear programming, and use the obtained reference values of each controlled variable as control commands; if not, use the theoretical optimal values of the controlled variables of the general new energy power station and the sending-end converter station as the reference values of the controlled variables and use the reference values of the controlled variables as control commands.

[0122] Based on the above analysis, the maximum active power transmission problem is transformed into a single-objective nonlinear programming problem with constraints. That is:

[0123] (32)

[0124] In the formula, U Mlim and I Mlim are the limits of the AC output voltage and current of the sending-end converter station respectively; P wjlim is the output power limit of the j th power station.

[0125] This problem belongs to a very small-scale programming problem. Using the initial guess points provided by Equation (17), various algorithms can be used to quickly obtain each controlled variable. For the Figure 2 shown system, the solution method based on the fmincon function in MATLAB is given below as a reference.

[0126] The solution function is:

[0127] [x, fval]=fmincon(fun, x0, A, b, Aeq, beq, lb, ub, nonlcon)

[0128] Among them:

[0129] The return value of x is the value of each controlled variable, that is, I w1 , I w2 , θ w1 , θ w2 , U M .

[0130] The return value of fval is the value of the objective function, that is, P M .

[0131] fun is the nonlinear objective function defined by the M file, i.e., formula (10).

[0132] x0 is the initial value of x, that is, formula (17).

[0133] A, b, Aeq, beq are defined linear constraints. This application does not involve linear constraints, that is, A=[], b=[], Aeq=[], beq=[].

[0134] lb and ub are the lower and upper bounds of the variable x, that is, lb=[0; 0; -π; -π; 0], ub=[ I w1max ; I w2max ;π;π; U Mlim ].

[0135] nonlcon is a nonlinear constraint defined by M file, and each constraint is shown in formula (32).

[0136] The x and fval obtained by iterative solution are the values ​​of each controlled variable and the optimal transmission active P M .

[0137] Step 102: The control instruction is transmitted to the new energy station and the sending-end converter station to implement fault ride-through control.

[0138] In this embodiment, a fault equivalent model of a new energy station and a sending-end converter station is proposed, which makes full use of the flexible control and coordination capabilities of the two converters, which is beneficial to improving the grid-connected performance of the new energy flexible direct current island system under faults. Moreover, when a fault of any degree occurs in the sending-end AC collection line, the new energy station and the sending-end converter station are controlled by control instructions, which greatly reduces the active power shortage caused by the sending-end fault to the onshore power grid, fully considers the operating constraints of the new energy station and the converter station, and ensures their safe operation under faults.

[0139] In one embodiment, Figure 4A detailed flowchart of a fault ride-through method for a new energy access converter station provided according to an embodiment of the present invention. This embodiment is further optimized and extended on the basis of the above-mentioned embodiments. The specific steps are as follows:

[0140] Step 1: Fault detection and information acquisition. Update the constraint conditions of the new energy power station and the sending-end converter station in real time U Mlim 、 I Mlim 、 P wjlim , and determine whether a fault has occurred. If so, obtain the fault information R f 、 R 0、 X 0, otherwise, continue to update the constraint conditions U Mlim 、 I Mlim 、 P wjlim .

[0141] Step 2: Calculation of control commands for the new energy power station and the converter station. Calculate the theoretical values of the current and voltage of the sending-end converter station when controlled according to (17), and the theoretical values of the active power output P * wj (including the power stations of the fault branch and the non-fault branch) of the new energy power station respectively through formulas (25), (28), (29), and (30), and determine whether each theoretical value is out of limits. If there is no constraint violation, directly use the calculated value of (17) as the control reference value; if any constraint is violated, use the calculated value of formula (17) as the initial guess point, and solve the reference values of each controlled quantity through nonlinear programming.

[0142] Step 3: Implement fault ride-through control. Transmit the control commands to the new energy power station and the sending-end converter station, and the two cooperate to achieve the maximum active power transmission during the fault. Determine whether the fault is removed. If so, the system resumes normal operation; otherwise, convey the control commands to the new energy power station and the sending-end converter station.

[0143] It should be understood that the magnitudes of the sequence numbers of the steps in the above embodiments do not mean the order of execution. The execution order of each process should be determined according to its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

[0144] This application has the following characteristics and brings the following beneficial effects:

[0145] 1. The fault equivalent model of the new energy power station and the sending-end converter station proposed in this application makes full use of the flexible control and cooperation capabilities of the two types of converters, which is conducive to improving the grid connection performance of the new energy flexible DC island system under faults.

[0146] 2. The active power maximum transmission theory proposed in this application has the beneficial effect that when any degree of fault occurs in the sending-end AC collection line, the new energy power station can transmit active power to the onshore power grid to the maximum extent, greatly reducing the active power shortage caused by the sending-end fault to the onshore power grid.

[0147] 3. The control method considering the operation constraints of the new energy power station and the converter station proposed in this application has the beneficial effect that by taking into account various operation constraints of the converter, its operation safety under faults is ensured.

[0148] As Figure 5 shown, the following is an embodiment of the fault ride-through system for new energy access to the converter station provided by the embodiments of the present disclosure. It belongs to the same inventive concept as the fault ride-through method for new energy access to the converter station in the above embodiments. For the details not described in detail in the embodiment of the fault ride-through system for new energy access to the converter station, reference can be made to the embodiment of the fault ride-through method for new energy access to the converter station.

[0149] An acquisition unit 50 is configured to detect faults of the new energy power station and the sending-end converter station, and acquire fault information after detecting the occurrence of a fault;

[0150] A calculation unit 51 is configured to calculate control instructions for the new energy power station and the sending-end converter station based on the fault information;

[0151] A control unit 52 is configured to transmit the control instructions to the new energy power station and the sending-end converter station to implement fault ride-through control.

[0152] Figure 6 It is a schematic hardware structure diagram of an electronic device for implementing various embodiments of the present invention.

[0153] The fault ride-through method for new energy access to the converter station provided by the embodiments of this application can be applied to an electronic device. Those skilled in the art can understand that the structure of the electronic device involved in the embodiments of the present invention does not constitute a limitation on the electronic device. The electronic device may include more or fewer components than shown, or combine certain components, or have different component arrangements. In the embodiments of the present invention, the electronic device includes, but is not limited to, a laptop computer, a desktop computer, a workbench, a personal digital assistant, a server, a blade server, a mainframe computer, and other suitable computers. The electronic device may also represent various forms of mobile devices, such as, a personal digital processor, a cellular phone, a smart phone, a wearable device, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the embodiments of the present application described herein and / or claimed.

[0154] The electronic device may include a processor, an external memory interface, an internal memory, a Universal Serial Bus (USB) interface, a charging management module, a power management module, a battery, a wireless communication module, an audio module, a speaker, a microphone, a sensor module, keys, a camera, a display screen, and a Subscriber Identity Module (SIM) card interface, etc.

[0155] It can be understood that the structure illustrated in the embodiments of the present application does not constitute a specific limitation on the electronic device. In other embodiments of the present application, the electronic device may include more or fewer components than those illustrated, or combine certain components, or split certain components, or have different component arrangements. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

[0156] The processor may include one or more processing units. For example, the processor may include a Central Processing Unit (CPU), etc., an Application Processor (AP), a modem processor, a Graphics Processing Unit (GPU), an Image Signal Processor (ISP), a controller, a memory, a video codec, a Digital Signal Processor (DSP), a baseband processor, and / or a Neural-Network Processing Unit (NPU), etc. Among them, different processing units may be independent devices or integrated in one or more processors.

[0157] Among them, the processor may be the nerve center and command center of the electronic device. The controller can generate operation control signals according to the instruction operation code and timing signal to complete the control of fetching and executing instructions.

[0158] A memory may also be provided in the processor for storing instructions and data. In some embodiments, the memory in the processor is a cache memory. This memory can save the instructions or data that the processor has just used or recycled. If the processor needs to use the instruction or data again, it can directly call it from this memory. This avoids repeated accesses, reduces the waiting time of the processor, and thus improves the system efficiency.

[0159] The external memory interface can be used to connect an external memory card, such as a MicroSD card, to expand the storage capacity of the electronic device. The external memory card communicates with the processor through the external memory interface to achieve the data storage function. For example, files such as music and videos are saved in the external memory card.

[0160] The internal memory can be used to store computer-executable program code, and the computer-executable program code includes instructions. The processor executes various functional applications and data processing of the electronic device by running the instructions stored in the internal memory. The internal memory can include a program storage area and a data storage area. The internal memory can include a high-speed random access memory and can also include a non-volatile memory, such as at least one disk storage device, a flash memory device, a universal flash storage (UFS), etc.

[0161] The wireless communication function of the electronic device can be implemented by an antenna, a wireless communication module, a modulation and demodulation processor, a baseband processor, etc.

[0162] The wireless communication module can provide wireless communication solutions applied to the electronic device, including wireless local area networks (WLANs) (such as wireless fidelity (Wi-Fi) networks), Bluetooth (BT), global navigation satellite systems (GNSSs), frequency modulation (FM), near field communication (NFC), infrared technology (IR), etc.

[0163] The electronic device can implement audio functions, etc. through an audio module, a speaker, a receiver, a microphone, a headphone jack, an application processor, etc.

[0164] The electronic device can implement a shooting function through an ISP, a camera, a video codec, a GPU, a display screen, an application processor, etc.

[0165] The electronic device can implement a display function through a GPU, a display screen, an application processor, etc.

[0166] The GPU is a microprocessor for image processing, connecting the display screen and the application processor. The GPU is used to execute mathematical and geometric calculations for graphics rendering. The processor can include one or more GPUs, which execute program instructions to generate or change display information.

[0167] The display screen is used to display images, videos, etc. The display screen includes a display panel.

[0168] In the storage medium provided in this application, there is a program product capable of implementing the fault ride-through method for a new energy access converter station.

[0169] The fault ride-through method for a new energy access converter station includes: detecting faults in the new energy power station and the sending-end converter station, and obtaining fault information after detecting the occurrence of a fault; calculating control instructions for the new energy power station and the sending-end converter station based on the fault information; and transmitting the control instructions to the new energy power station and the sending-end converter station to achieve fault ride-through control.

[0170] In some possible implementation manners, the subject matter of the present disclosure, the fault ride-through method and system for a new energy access converter station, may be implemented in the form of a program product, which includes program code. When the program product runs on a terminal device, the program code is used to cause the terminal device to execute the steps according to various exemplary embodiments of the present disclosure described in the "Exemplary Method" section above in this specification.

[0171] The storage medium of the present disclosure may adopt any combination of one or more readable media. The readable media may be a readable signal medium or a readable storage medium. The readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples (a non-exhaustive list) of the readable storage medium include: an electrical connection having one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0172] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A fault ride-through method for a new energy access converter station, characterized in that Including: Conduct fault detection on the new energy power station and the sending-end converter station, and obtain fault information after detecting the occurrence of a fault; Based on the fault information, calculate the effective value of the current of the sending-end converter station, the output voltage of the sending-end converter station, and the active power output of the new energy power station when controlling according to the theoretical optimal values of the controlled quantities of the general new energy power station and the sending-end converter station; Judge whether the effective value of the current of the sending-end converter station, the output voltage of the sending-end converter station, and the active power output of the new energy power station exceed the limit. If so, use the theoretical optimal values of the controlled quantities of the general new energy power station and the sending-end converter station as the initial guess points, solve the reference values of each controlled quantity through nonlinear programming, and use the obtained reference values of each controlled quantity as control commands; If not, use the theoretical optimal values of the controlled quantities of the general new energy power station and the sending-end converter station as the reference values of the controlled quantities and use the reference values of the controlled quantities as control commands; The theoretical optimal values of the controlled quantities of the general new energy power station and the sending-end converter station are characterized as: where, w1 represents the new energy power station on the fault branch, and wi represents the new energy power stations on the non-fault branches, is the i maximum output current of the ith power station, is the fault resistance, X is the leakage inductance of the connecting transformer, is the equivalent reactance from the fault point to the PCC point, X = X t + X 0, where * represents the theoretical optimal value without considering other constraints, U M is the output voltage of the sending converter station, θ wi is the phase of the output current of the new energy power station; Transmit the control command to the new energy power station and the sending-end converter station to achieve fault ride-through control.

2. The fault ride-through method for a new energy access converter station according to claim 1, wherein Before conducting fault detection on the new energy power station and the sending-end converter station and obtaining fault information after detecting the occurrence of a fault, the fault ride-through method for the new energy access converter station further includes: establishing a fault equivalent model of the new energy power station and the sending-end converter station: Equivalently model the new energy power station and the sending-end converter station as a controlled current source and a controlled voltage source respectively, where the effective value and phase angle of the output current of the controlled current source are controlled quantities, and the effective value of the output voltage of the controlled voltage source is a controlled quantity.

3. The fault ride-through method for a new energy access converter station according to claim 1, wherein Based on the fault information, calculate the effective value of the current of the sending-end converter station when controlling according to the theoretical optimal values of the controlled quantities of the general new energy power station and the sending-end converter station according to the following formula: ； ； ； Wherein, is the fault resistance, is the maximum output current of the i th substation, is the equivalent reactance from the fault point to the PCC point.

4. The fault ride-through method for a new energy access converter station according to claim 1, characterized in that, Based on the fault information, calculate the output voltage of the sending-end converter station when controlling according to the theoretical optimal values of the controlled quantities of the general new energy power station and the sending-end converter station according to the following formula: ； Wherein, is the fault resistance, is the maximum output current of the i th substation, is the equivalent reactance from the fault point to the PCC point, is the leakage inductance of the connection transformer.

5. The fault ride-through method for a new energy access converter station according to claim 1, characterized in that, Based on the fault information, calculate the active power output of the new energy power station when controlling according to the theoretical optimal values of the controlled quantities of the general new energy power station and the sending-end converter station according to the following formula: ； Wherein, and are the active powers output by the new energy power stations on the fault branch and the non-fault branch respectively, represents the equivalent resistance and reactance from the outlet of the new energy power station on the i th non-fault branch to the PCC point, is the fault resistance, are the equivalent resistance and reactance from the fault point to the PCC point respectively.

6. A fault ride-through system for a new energy source connected to a converter station, characterized in that The system is used to implement the fault ride-through method for the new energy access converter station as described in any one of claims 1 to 5; The system includes: An acquisition unit for conducting fault detection on the new energy power station and the sending-end converter station and obtaining fault information after detecting the occurrence of a fault; A calculation unit for calculating control commands for the new energy power station and the sending-end converter station based on the fault information; A control unit for transmitting the control command to the new energy power station and the sending-end converter station to achieve fault ride-through control.

7. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein When the processor executes the program, it implements the steps of the fault ride-through method for the new energy access converter station as described in any one of claims 1 to 5.

8. A storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the fault ride-through method for the new energy access converter station as described in any one of claims 1 to 5.

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