Alternating current line overload regulation and control method and device based on multi-terminal direct current converter, terminal equipment and computer readable storage medium

Abstract

The invention discloses an alternating current line overload regulation and control method and device based on a multi-terminal direct current converter, terminal equipment and a computer readable storage medium. The method comprises the following steps: acquiring an alternating current line parameter, a converter parameter, a generator parameter and a penalty parameter in a power system based on the multi-terminal direct current converter; constructing an AC line overload scheduling model, and an AC system inequality constraint, a multi-terminal DC system inequality constraint, a line equality constraint and a Jacobian equality constraint corresponding to the model by taking the minimum quantity exceeding the constraint as a target according to the obtained parameters; under the constraint of each constraint condition, generating an active power set value of a converter and an active power set value of a generator when the quantity exceeding the constraint limit is minimum; and respectively adjusting the active power of the converter and the active power of the generator to corresponding set values through a controller in the power system. According to the invention, it is ensured that the multi-terminal direct-current power transmission system can be kept stable during alternating-current line overload regulation and control.

Description

Technical Field

[0001] The present invention relates to the technical field of AC line overload control, and in particular to an AC line overload control method, device, terminal equipment and computer-readable storage medium based on a multi-terminal DC converter. Background Art

[0002] With the rapid development of my country's economy, the growing demand for electricity has brought new challenges and requirements to the operation of the power system, including the problem of transmission line overload. Transmission line overload will seriously harm the stability of the power grid and the safety of electricity use, causing the line to overheat or even burn, and then causing power outages and triggering a series of chain reactions. Therefore, it is necessary to take timely measures to avoid accidents when the line is overloaded.

[0003] At present, when an AC line is overloaded, traditional protection mechanisms such as current cutting and load adjustment are still relied on to suppress and dispatch the overload of the AC line. In recent years, with the continuous development and maturity of voltage source converters, high-voltage DC transmission technology has become a line overload solution with the advantages of reducing costs and power losses. At the same time, with the continuous development of renewable energy, there have been tremendous changes in power generation, transmission, and consumption, all of which require the power grid to have sufficient stability. When embedded in the power grid, the multi-terminal DC system has the effects of improving the frequency response of the power grid and regional oscillation damping. Therefore, it is an ideal technology that can effectively alleviate AC line overload and support future AC power grids.

[0004] However, the overload control technology of multi-terminal DC converters in multi-terminal DC transmission systems is still relatively blank. In actual application, when one of the converter stations in the multi-terminal DC transmission system is out of operation, other converter stations can continue to exchange power through power coordination control to ensure the continued operation of the system. However, after updating other converter station nodes, the operating conditions and parameters of the system have changed, which may cause voltage instability in the system. Summary of the invention

[0005] The embodiments of the present invention provide an AC line overload control method, apparatus, terminal device and computer-readable storage medium based on a multi-terminal DC converter. By constructing constraints, it is ensured that after the multi-terminal DC converter station and the AC generator power nodes are updated, the multi-terminal DC transmission system can remain stable and avoid the problem of voltage instability.

[0006] An embodiment of the present invention provides an AC line overload control method based on a multi-terminal DC converter, comprising:

[0007] Acquiring AC line parameters, converter parameters, generator parameters and penalty parameters in a multi-terminal DC converter power system;

[0008] According to the AC line parameters, converter parameters, generator parameters and penalty parameters, with the goal of minimizing the amount exceeding the constraint limit, an AC line overload dispatching model is constructed, as well as the AC system inequality constraints, multi-terminal DC system inequality constraints, line equality constraints and Jacobi equality constraints corresponding to the AC line overload dispatching model;

[0009] Under the constraints of AC system inequality constraints, multi-terminal DC system inequality constraints, line equality constraints and Jacobi equality constraints, the active power setting value of the converter and the active power setting value of the generator are generated when the amount exceeding the constraint limit is minimized;

[0010] The active power of the converter and the active power of the generator are adjusted to the active power setting value of the converter and the active power setting value of the generator respectively through the controller in the power system.

[0011] Furthermore, the AC line overload dispatching model is as follows:

[0012]

[0013] in, Indicates the active power setting value of the converter, P G represents the set value of the active power of the generator, a(j) represents the slack variable of the active power of line j, β(j) represents the slack variable of the DC current of line j, c represents the line control range corresponding to the AC line overload dispatch model, Indicates the target value of AC line active power, P L (j) represents the active power of AC line j, W L The diagonal weighted matrix corresponding to the active power of the AC line, ΔP G Indicates the change in active power of the generator, W G Represents the diagonal weighted matrix corresponding to the change in active power of the generator, Indicates the active power change of the converter, W MMC Represents the diagonal weighted matrix corresponding to the active power change of the converter, ρ α and ρ β represents the diagonal weighted matrix of the penalty term, γ is a preset constant, represents the maximum active power in AC line j, I DC (j) represents the current value of AC line j, represents the maximum current value in AC line j, k v is the PV droop constant, Indicates the reference value of the DC bus, V DC Indicates the DC bus voltage.

[0014] Furthermore, the AC system inequality constraints are as follows:

[0015]

[0016]

[0017] in, Indicates the maximum allowable change in the ramp rate of all AC system generators. and Respectively represent the lower and upper limits of the generator power, and Respectively represent the lower and upper limits of the AC voltage, V AC (j) represents the AC voltage value of line j.

[0018] Furthermore, the inequality constraints of the multi-terminal DC system are as follows:

[0019]

[0020] in, Indicates the maximum active power value injected by the converter into the AC system. Indicates the maximum allowable change in the active power setting value of all AC system converters.

[0021] Furthermore, the Jacobi equality constraint is:

[0022]

[0023] Where J represents the Jacobian matrix of the AC power grid, ΔQ represents the change in bus reactive power in the AC power grid, and ΔV AC Indicates the change in AC voltage in the AC power grid.

[0024] Furthermore, the target value of the AC line active power in the AC line overload dispatch model is determined by:

[0025] Real-time monitoring of the absolute value of each AC line;

[0026] When the measured absolute value does not exceed the first preset threshold, the measured absolute value is used as the target value of the active power of the AC line;

[0027] When the measured absolute value exceeds a first preset threshold value and does not exceed a second preset threshold value, the first preset threshold value is used as a target value of the active power of the AC line;

[0028] When the measured absolute value exceeds the second preset threshold, the measured absolute value is subtracted from twice the second preset threshold, and the calculated result is used as the target value of the AC line active power.

[0029] Based on the above method embodiment, the present invention provides a corresponding device embodiment, including: a parameter acquisition module, an AC line overload scheduling model construction module, a scheduling model solving module, and a power adjustment module;

[0030] A parameter acquisition module, used to acquire AC line parameters, converter parameters, generator parameters and penalty parameters in a multi-terminal DC converter power system;

[0031] An AC line overload dispatch model construction module is used to construct an AC line overload dispatch model based on AC line parameters, converter parameters, generator parameters and penalty parameters, with the goal of minimizing the amount exceeding the constraint limit, as well as AC system inequality constraints, multi-terminal DC system inequality constraints, line equality constraints and Jacobi equality constraints corresponding to the AC line overload dispatch model;

[0032] A dispatch model solving module is used to generate the active power setting value of the converter and the active power setting value of the generator when the amount exceeding the constraint limit is minimum under the constraints of the AC system inequality constraints, the multi-terminal DC system inequality constraints, the line equality constraints and the Jacobi equality constraints;

[0033] The power adjustment module is used to adjust the active power of the converter and the active power of the generator to the active power setting value of the converter and the active power setting value of the generator respectively through a controller in the power system.

[0034] Furthermore, the AC line overload dispatch model construction module includes: an AC power target value confirmation submodule;

[0035] The AC power target value confirmation submodule includes: an AC power real-time monitoring unit, a first target value confirmation unit, a second target value confirmation unit, and a third target value confirmation unit;

[0036] AC power real-time monitoring unit, used to monitor the absolute value of each AC line in real time;

[0037] A first target value confirmation unit, configured to use the measured absolute value as a target value of the AC line active power when the measured absolute value does not exceed a first preset threshold value;

[0038] A second target value confirmation unit, configured to use the first preset threshold as a target value of the AC line active power when the measured absolute value exceeds the first preset threshold and does not exceed the second preset threshold;

[0039] The third target value confirmation unit is used to, when the measured absolute value exceeds the second preset threshold, subtract the measured absolute value from twice the second preset threshold, and use the calculated result as the target value of the active power of the AC line.

[0040] Based on the above-mentioned method embodiment, the present invention provides a corresponding terminal device embodiment, including: a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, the steps of the AC line overload control method based on a multi-terminal DC converter as described in the present invention are implemented.

[0041] Based on the above method item embodiments, the present invention provides a corresponding computer-readable storage medium item embodiment, including: a stored computer program, which, when the computer program is running, controls the device where the computer-readable storage medium is located to execute the steps of the AC line overload control method based on a multi-terminal DC converter as described in the present invention.

[0042] Compared with the prior art, the beneficial effects of the embodiment of this solution are:

[0043] The present invention obtains AC line parameters, converter parameters, generator parameters and penalty parameters in a multi-terminal DC converter power system, and based on the obtained AC line parameters, converter parameters, generator parameters and penalty parameters, takes the minimum amount exceeding the constraint limit as the objective function, constructs an AC line overload scheduling model, and the AC system inequality constraints, multi-terminal DC system inequality constraints, line equality constraints and Jacobi equality constraints corresponding to the model, and restricts in the optimization problem through the constructed constraints, thereby ensuring the power balance between the multi-terminal DC system and the AC system. Then, under the constraints of the AC system inequality constraints, the multi-terminal DC system inequality constraints, the line equality constraints and the Jacobi equality constraints, the power setting values ​​of the converter and the generator when the amount exceeding the constraint limit is the smallest are solved, thereby obtaining the optimal power setting value, so that the performance of the system is optimized. Finally, through the controller in the power system, the optimal power setting value obtained by solving is applied to the converter and the generator to achieve power adjustment.

[0044] In summary, the present invention ensures that the system can remain stable and avoid voltage instability after the multi-terminal DC converter station and the AC generator power nodes are updated through the constructed constraints. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a flow chart of an AC line overload control method based on a multi-terminal DC converter provided by an embodiment of the present invention;

[0046] Figure 2 It is a flowchart of a process for confirming an AC line active power target value provided by an embodiment of the present invention;

[0047] Figure 3 is a schematic diagram of the topological structure of a 39-node system provided by an embodiment of the present invention;

[0048] Figure 4 is a variation trend diagram of the DC voltage of each overloaded line in a 39-node system provided by an embodiment of the present invention;

[0049] Figure 5 It is a structural schematic diagram of an AC line overload control device based on a multi-terminal DC converter provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0050] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features.

[0052] like Figure 1 As shown, an embodiment of the present invention provides an AC line overload control method based on a multi-terminal DC converter, the method comprising at least the following steps:

[0053] Step S1: Acquire AC line parameters, converter parameters, generator parameters and penalty parameters in a multi-terminal DC converter power system;

[0054] For step S1, in the multi-terminal DC converter power system of the present invention, the AC line parameters include: target value of the active power of the AC line The diagonal weighted matrix W corresponding to the active power of the AC line L , the maximum active power in AC line j The maximum current value in AC line j Lower limit of AC voltage Upper limit of AC voltage

[0055] The above converter parameters include: the diagonal weighted matrix W corresponding to the active power variation of the converter MMC Maximum allowable change in active power setting value of all AC system converters The maximum active power value injected by the converter into the AC system

[0056] The above generator parameters include: the diagonal weighted matrix W corresponding to the active power change of the generator G, the maximum allowable change in the ramp rate of all AC system generators Lower limit of generator power Upper limit of generator power

[0057] The penalty parameters include: the slack variable a(j) of the active power of line j, the slack variable β(j) of the DC current of line j, the diagonal weighted matrix ρ of the penalty term α and ρ β , preset constant γ, PV droop constant k v , DC bus reference value Jacobian matrix J of AC power grid;

[0058] The line control range c corresponding to the AC line overload dispatching model and the active power setting value of the converter mentioned in the invention Generator active power setting value P G , the active power P of AC line j L (j) The change in active power of the generator ΔP G , the active power change of the converter The current value I of AC line j DC (j) DC bus voltage V DC , AC voltage value V of line j AC (j), the change of bus reactive power in the AC power grid ΔQ, the change of AC voltage in the AC power grid ΔV AC ; These data items are all unknown data items and will be calculated in the subsequent process of solving the AC line overload scheduling model.

[0059] Among them, the target value of the AC line active power in the AC line parameters is Refers to the power level that is desired to be achieved during overload regulation.

[0060] The following is a detailed description of the process of confirming the target value of the AC line active power:

[0061] like Figure 2 As shown in FIG. 1 , the process of confirming the target value of the AC line active power includes the following steps:

[0062] Step S101: real-time monitoring of the absolute value of each AC line;

[0063] For step S101, firstly, the power value of the AC line is obtained in real time through monitoring equipment and sensors. In order to understand the system load in time.

[0064] Prior to this, different threshold ranges of AC line power and AC line active power target values ​​corresponding to different threshold ranges are preset. In this embodiment, the first preset threshold is set to The second preset threshold is

[0065] Step S102: when the measured absolute value does not exceed the first preset threshold, the measured absolute value is used as the target value of the AC line active power;

[0066] For step S102, when the measured power value , the line load level is level 1, indicating that the line is lightly loaded and there is no need to consider overloading. In this case, the controller tends to maintain the current load level and the measured power value As the target value of AC line active power Right now Where γ1 is a constant less than 1.

[0067] Step S103: when the measured absolute value exceeds the first preset threshold value and does not exceed the second preset threshold value, the first preset threshold value is used as the target value of the AC line active power;

[0068] For step S103, when the measured power value , the line load level is level 2, indicating that the controller begins to pay attention to the line load and tends to reduce the line load to the minimum value of this level. In this case, the controller sets the first preset threshold As the target value of AC line active power Right now

[0069] Step S104: when the measured absolute value exceeds the second preset threshold, the measured absolute value is subtracted from twice the second preset threshold, and the calculated result is used as the target value of the AC line active power.

[0070] For step S104, when the measured power value There are two cases. The first case is , the line load level is level 3, indicating that the line load is close to the limit. The controller gives priority to the lines at this level and reduces the load to the minimum value of this level, that is, The second case is , the line load level is level 4, indicating that the line load has exceeded the constraint range. Right now Reduce the load to the minimum level, but at this time If the load increases, the penalty in the controller will increase. At the same time, a serious overload signal will be issued to notify technical personnel to intervene and adopt other methods to solve the overload problem of this road.

[0071] like Figure 3 As shown, a 39-bus system is used as an example to control line overload:

[0072] In this system, the wind turbines are connected to busbars 2 and 4 of the multi-terminal DC system via cables, and the remaining busbars are connected via overhead DC lines. Assuming that a system fault occurs at t=2s, the line between connection nodes 15-16 is disconnected, which will cause the lines between connection nodes 2-3, 3-4, 16-17, 16-19, and 17-18 to be overloaded. After the line disconnection causes a power outage, the controller starts to receive data to determine the line load level and the corresponding AC line active power target value.

[0073] Step S2: According to the AC line parameters, converter parameters, generator parameters and penalty parameters, with the goal of minimizing the amount exceeding the constraint limit, construct an AC line overload dispatching model, as well as AC system inequality constraints, multi-terminal DC system inequality constraints, line equality constraints and Jacobi equality constraints corresponding to the AC line overload dispatching model;

[0074] In a preferred embodiment, the AC line overload scheduling model is specifically:

[0075]

[0076]

[0077] in, Indicates the active power setting value of the converter, P G represents the set value of the active power of the generator, a(j) represents the slack variable of the active power of line j, β(j) represents the slack variable of the DC current of line j, c represents the line control range corresponding to the AC line overload dispatch model, Indicates the target value of AC line active power, P L (j) represents the active power of AC line j, W L The diagonal weighted matrix corresponding to the active power of the AC line, ΔP G Indicates the change in active power of the generator, W G Represents the diagonal weighted matrix corresponding to the change in active power of the generator, Indicates the active power change of the converter, W MMC Represents the diagonal weighted matrix corresponding to the active power change of the converter, ρ α and ρ β represents the diagonal weighted matrix of the penalty term, γ is a preset constant, represents the maximum active power in AC line j, I DC (j) represents the current value of AC line j, represents the maximum current value in AC line j, k v is the PV droop constant, Indicates the reference value of the DC bus, V DC Indicates the DC bus voltage.

[0078] In a preferred embodiment, the AC system inequality constraint is specifically:

[0079]

[0080] in, Indicates the maximum allowable change in the ramp rate of all AC system generators. and Respectively represent the lower and upper limits of the generator power, and Respectively represent the lower and upper limits of the AC voltage, V AC (j) represents the AC voltage value of line j.

[0081] In a preferred embodiment, the multi-terminal DC system inequality constraint is specifically:

[0082]

[0083] in, Indicates the maximum active power value injected by the converter into the AC system. Indicates the maximum allowable change in the active power setting value of all AC system converters.

[0084] In a preferred embodiment, the Jacobi equality constraint is specifically:

[0085]

[0086] Where J represents the Jacobian matrix of the AC power grid, ΔQ represents the change in bus reactive power in the AC power grid, and ΔV AC Indicates the change in AC voltage in the AC power grid.

[0087] For step S2, the AC line overload scheduling model is used in the multi-terminal DC system to deal with the power scheduling problem when the AC line is overloaded. Its core goal is to minimize or eliminate the impact of overload conditions by optimizing scheduling to ensure the safe and stable operation of the system.

[0088] Compared with AC generators, multi-terminal DC converter stations can quickly change their active power output by adjusting control parameters without being limited by the ramp rate, so they are more controllable. However, in actual use, when one of the converter stations in the multi-terminal DC system exits operation, other converter stations can continue to exchange power through power coordination control. However, after updating other converter station nodes, the operating conditions and parameters of the system change, resulting in voltage instability in the system. This problem has limited the development of multi-terminal DC converter stations to a certain extent. To solve this problem, the present invention constructs a mathematical model with the goal of minimizing the amount exceeding the constraint limit, and at the same time constructs AC system inequality constraints, multi-terminal DC system inequality constraints, line equality constraints and Jacobi equality constraints. The voltage and current of each node are limited by the AC system inequality constraints, the converter capacity and voltage level are limited by the multi-terminal DC system inequality constraints, the power exchange balance of each node is ensured by the line equality constraints, and the stability of the node voltage and frequency is ensured by the Jacobi equality constraints, so that the power coordination control between converter stations is realized under the joint action of these constraints to ensure the power exchange balance of each node.

[0089] The circuit equality constraints are:

[0090]

[0091] Among them, N dc represents the number of dispatchable converter stations, P MMCn Represents the active power of the nth converter station.

[0092] It should be noted that the Jacobian matrix in the Jacobian equation constraint is used to analyze the stability of the system. When updating the set values ​​of the multi-terminal DC converter station and the AC generator, the Jacobian equation constraint can ensure that these updates will not cause voltage instability. Specifically, let the Jacobian matrix J r The minimum eigenvalue λ is positive, which can ensure that the system voltage is within an acceptable range under any operating conditions. Therefore, the simplified Jacobian matrix J r Indicates the sensitivity of AC voltage to reactive power.

[0093] Step S3: Under the constraints of the AC system inequality constraint, the multi-terminal DC system inequality constraint, the line equality constraint and the Jacobi equality constraint, the active power setting value of the converter and the active power setting value of the generator are generated when the amount exceeding the constraint limit is the minimum;

[0094] For step S3, specifically, under the above-mentioned constraints, with the goal of minimizing the amount exceeding the constraint limit, a genetic algorithm is used to solve the AC line overload scheduling model. The algorithm will find the optimal decision variable value based on the set objective function and constraints, thereby obtaining the active power setting value of the converter and the active power setting value of the generator.

[0095] Step S4: adjusting the active power of the converter and the active power of the generator to the active power setting value of the converter and the active power setting value of the generator respectively through the controller in the power system.

[0096] For step S4, after solving the inter-group coordinated optimization scheduling model of step S3, the active power setting value of the converter and the active power setting value of the generator can be obtained. The controller changes the control parameters of the converter and the generator to achieve the control target that the active power of the converter and the active power of the generator reach the set value respectively. In this way, the load and power distribution of the AC line can be effectively scheduled to ensure the stable operation of the system, thereby solving the problem of AC line overload. In this embodiment, when the DC voltage bus voltage is about to reach its lower limit, the controller will control the active power of the multi-terminal DC converter station and the AC generator to adjust according to Figure 4 From the DC voltage variation trend of each overloaded line shown in the figure, it can be seen that when t approaches 50s, the DC bus voltage is about to reach its lower limit. In order to ensure the stable operation of the system, the controller will adjust the active power of the multi-terminal DC converter station and the AC generator accordingly to make the voltage at each overloaded line rise steadily.

[0097] like Figure 5 As shown, based on the above method embodiment, a corresponding device embodiment is provided;

[0098] An embodiment of the present invention provides an AC line overload control device based on a multi-terminal DC converter, comprising: a parameter acquisition module, an AC line overload scheduling model construction module, a scheduling model solving module, and a power adjustment module;

[0099] A parameter acquisition module, used to acquire AC line parameters, converter parameters, generator parameters and penalty parameters in a multi-terminal DC converter power system;

[0100] An AC line overload dispatch model construction module is used to construct an AC line overload dispatch model based on AC line parameters, converter parameters, generator parameters and penalty parameters, with the goal of minimizing the amount exceeding the constraint limit, as well as AC system inequality constraints, multi-terminal DC system inequality constraints, line equality constraints and Jacobi equality constraints corresponding to the AC line overload dispatch model;

[0101] A dispatch model solving module is used to generate the active power setting value of the converter and the active power setting value of the generator when the amount exceeding the constraint limit is minimum under the constraints of the AC system inequality constraints, the multi-terminal DC system inequality constraints, the line equality constraints and the Jacobi equality constraints;

[0102] The power adjustment module is used to adjust the active power of the converter and the active power of the generator to the active power setting value of the converter and the active power setting value of the generator respectively through a controller in the power system.

[0103] In a preferred embodiment, the AC line overload scheduling model construction module includes: an AC power target value confirmation submodule;

[0104] The AC power target value confirmation submodule includes: an AC power real-time monitoring unit, a first target value confirmation unit, a second target value confirmation unit, and a third target value confirmation unit;

[0105] AC power real-time monitoring unit, used to monitor the absolute value of each AC line in real time;

[0106] A first target value confirmation unit, configured to use the measured absolute value as a target value of the AC line active power when the measured absolute value does not exceed a first preset threshold value;

[0107] A second target value confirmation unit, configured to use the first preset threshold as a target value of the AC line active power when the measured absolute value exceeds the first preset threshold and does not exceed the second preset threshold;

[0108] The third target value confirmation unit is used to, when the measured absolute value exceeds the second preset threshold, subtract the measured absolute value from twice the second preset threshold, and use the calculated result as the target value of the active power of the AC line.

[0109] It can be understood that the above-mentioned device item embodiments correspond to the method item embodiments of the present invention, and can implement the AC line overload control method based on the multi-terminal DC converter provided by any one of the above-mentioned method item embodiments of the present invention.

[0110] It should be noted that the device embodiments described above are merely illustrative, and some or all of the modules may be selected according to actual needs to achieve the purpose of the present embodiment. In addition, in the accompanying drawings of the device embodiments provided by the present invention, the connection relationship between the modules indicates that there is a communication connection between them, which may be specifically implemented as one or more communication buses or signal lines. Those of ordinary skill in the art may understand and implement the present invention without creative work.

[0111] Based on the above-mentioned embodiment of the AC line overload control method based on a multi-terminal DC converter, another embodiment of the present invention provides a terminal device, which includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, the AC line overload control method based on a multi-terminal DC converter according to any embodiment of the present invention is implemented.

[0112] Exemplarily, in this embodiment, the computer program may be divided into one or more modules, which are stored in the memory and executed by the processor to implement the present invention. The one or more module elements may be a series of computer program instruction segments capable of implementing specific functions, which are used to describe the execution process of the computer program in the terminal device.

[0113] The terminal device may be a computing device such as a desktop computer, a notebook, a PDA, a cloud server, etc. The terminal device may include, but is not limited to, a processor and a memory.

[0114] The processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc. The processor is the control center of the terminal device, and uses various interfaces and lines to connect various parts of the entire terminal device.

[0115] Based on the above method embodiment, another embodiment is provided: another embodiment of the present invention provides a computer-readable storage medium, including a stored computer program, wherein when the computer program is running, the device where the computer-readable storage medium is located is controlled to execute the AC line overload control method based on a multi-terminal DC converter described in any one of the above method embodiments of the present invention.

[0116] Wherein, the module / unit integrated with the AC line overload control device / terminal equipment based on the multi-terminal DC converter, if implemented in the form of a software functional unit and sold or used as an independent product, can be stored in a computer-readable storage medium. Based on such an understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Wherein, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form, etc. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium, etc.

[0117] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for controlling AC line overload based on a multi-terminal DC converter, characterized in that: include: Acquiring AC line parameters, converter parameters, generator parameters and penalty parameters in a multi-terminal DC converter power system; According to the AC line parameters, converter parameters, generator parameters and penalty parameters, with the goal of minimizing the amount exceeding the constraint limit, an AC line overload scheduling model is constructed, as well as AC system inequality constraints, multi-terminal DC system inequality constraints, line equality constraints and Jacobi equality constraints corresponding to the AC line overload scheduling model; Under the constraints of the AC system inequality constraints, the multi-terminal DC system inequality constraints, the line equality constraints and the Jacobi equality constraints, the active power setting value of the converter and the active power setting value of the generator are generated when the amount exceeding the constraint limit is minimized; The active power of the converter and the active power of the generator are adjusted to the active power setting value of the converter and the active power setting value of the generator respectively through the controller in the power system.

2. The AC line overload control method based on a multi-terminal DC converter according to claim 1 is characterized in that: The AC line overload scheduling model is specifically: in, Indicates the active power setting value of the converter, P G represents the set value of the active power of the generator, a(j) represents the slack variable of the active power of line j, β(j) represents the slack variable of the DC current of line j, c represents the line control range corresponding to the AC line overload dispatch model, Indicates the target value of AC line active power, P L (j) represents the active power of AC line j, W L The diagonal weighted matrix corresponding to the active power of the AC line, ΔP G Indicates the change in active power of the generator, W G Represents the diagonal weighted matrix corresponding to the change in active power of the generator, Indicates the active power change of the converter, W MMC Represents the diagonal weighted matrix corresponding to the active power change of the converter, ρ α and ρ β represents the diagonal weighted matrix of the penalty term, γ is a preset constant, represents the maximum active power in AC line j, I DC (j) represents the current value of AC line j, represents the maximum current value in AC line j, k v is the PV droop constant, Indicates the reference value of the DC bus, V DC Indicates the DC bus voltage.

3. The AC line overload control method based on a multi-terminal DC converter according to claim 2 is characterized in that: The AC system inequality constraints are specifically: in, Indicates the maximum allowable change in the ramp rate of all AC system generators. and Respectively represent the lower and upper limits of the generator power, and Respectively represent the lower and upper limits of the AC voltage, V AC (j) represents the AC voltage value of line j.

4. The AC line overload control method based on a multi-terminal DC converter according to claim 3 is characterized in that: The multi-terminal DC system inequality constraints are specifically: in, Indicates the maximum active power value injected by the converter into the AC system. Indicates the maximum allowable change in the active power setting value of all AC system converters.

5. The AC line overload control method based on a multi-terminal DC converter according to claim 4 is characterized in that: The Jacobi equality constraint is specifically: Where J represents the Jacobian matrix of the AC power grid, ΔQ represents the change in bus reactive power in the AC power grid, and ΔV AC Indicates the change in AC voltage in the AC power grid.

6. The AC line overload control method based on a multi-terminal DC converter according to claim 5 is characterized in that: The target value of the AC line active power in the AC line overload scheduling model is determined by: Real-time monitoring of the absolute value of each AC line; When the measured absolute value does not exceed a first preset threshold, taking the measured absolute value as a target value of the AC line active power; When the measured absolute value exceeds a first preset threshold value and does not exceed a second preset threshold value, the first preset threshold value is used as a target value of the active power of the AC line; When the measured absolute value exceeds the second preset threshold, the measured absolute value is subtracted from twice the second preset threshold, and the calculated result is used as the target value of the AC line active power.

7. An AC line overload control device based on a multi-terminal DC converter, characterized in that: include: Parameter acquisition module, AC line overload dispatch model construction module, dispatch model solving module, and power adjustment module; The parameter acquisition module is used to acquire AC line parameters, converter parameters, generator parameters and penalty parameters in a multi-terminal DC converter power system; The AC line overload dispatch model construction module is used to construct an AC line overload dispatch model according to the AC line parameters, converter parameters, generator parameters and penalty parameters, with the goal of minimizing the amount exceeding the constraint limit, as well as the AC system inequality constraints, multi-terminal DC system inequality constraints, line equality constraints and Jacobi equality constraints corresponding to the AC line overload dispatch model; The scheduling model solving module is used to generate the active power setting value of the converter and the active power setting value of the generator when the amount exceeding the constraint limit is minimum under the constraints of the AC system inequality constraints, the multi-terminal DC system inequality constraints, the line equality constraints and the Jacobi equality constraints; The power adjustment module is used to adjust the active power of the converter and the active power of the generator to the active power setting value of the converter and the active power setting value of the generator respectively through a controller in the power system.

8. The AC line overload control device based on a multi-terminal DC converter according to claim 7, characterized in that: The AC line overload dispatch model building module includes: an AC power target value confirmation submodule; The AC power target value confirmation submodule includes: an AC power real-time monitoring unit, a first target value confirmation unit, a second target value confirmation unit, and a third target value confirmation unit; The AC power real-time monitoring unit is used to monitor the measured absolute value of each AC line in real time; The first target value confirmation unit is used to use the measured absolute value as the target value of the AC line active power when the measured absolute value does not exceed a first preset threshold value; The second target value confirmation unit is used to use the first preset threshold as the target value of the AC line active power when the measured absolute value exceeds the first preset threshold and does not exceed the second preset threshold; The third target value confirmation unit is used to, when the measured absolute value exceeds the second preset threshold, subtract the measured absolute value from twice the second preset threshold, and use the calculated result as the target value of the active power of the AC line.

9. A terminal device, characterized in that: include: A processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein when the processor executes the computer program, the AC line overload control method based on a multi-terminal DC converter according to any one of claims 1 to 6 is implemented.

10. A computer-readable storage medium, characterized in that: include: A stored computer program, wherein when the computer program is running, the device where the computer-readable storage medium is located is controlled to execute the AC line overload control method based on a multi-terminal DC converter according to any one of claims 1 to 6.

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