Electrical parameter design method for current limiting reactor of direct current energy consumption device

Abstract

The embodiment of the invention relates to the technical field of direct-current power transmission, and discloses an electrical parameter design method for a current limiting reactor of a direct-current energy consumption device, and the method comprises the steps: determining a current change rate reference value k; acquiring the current average change rate r1 and the current instantaneous change rate r2 of the main loop of the energy consumption device in the conduction process of the switch module; according to the current change rate reference value k, the current average change rate r1 and the current instantaneous change rate r2, the inductance value range of the current limiting reactor is calculated; and analyzing the turn-off process of the switch module, and calculating the target inductance value of the current-limiting reactor based on the inductance value range of the current-limiting reactor. According to the embodiment of the invention, the specific parameters of the current-limiting reactor are determined according to the working characteristics of the flexible chopping type direct-current energy consumption device, and the problem that the electrical parameters of the current-limiting reactor of the flexible chopping type direct-current energy consumption device are difficult to design in the prior art is solved.

Description

Technical Field

[0001] The embodiments of the present disclosure relate to the field of direct current transmission technology, and in particular to a method, system, device and storage medium for designing electrical parameters of a current limiting reactor of a flexible chopper type direct current energy dissipation device. Background Art

[0002] Flexible DC transmission technology is the main technical means to solve the problem of offshore wind power grid connection. However, when the receiving AC power grid fails, the wind farm energy that cannot be consumed in time will cause the DC voltage to rise rapidly, posing a threat to the safety of the converter valve and the entire system. Therefore, a DC energy consumption device is needed to consume the energy that the system cannot transmit normally, so as to stabilize the DC voltage and assist the system in completing fault crossing.

[0003] Controllable high-power semiconductor switching devices are an important component in the research of DC energy dissipation devices. Currently, DC energy dissipation device solutions mainly use integrated gate-commutated thyristors (IGCT) and insulated gate bipolar transistors (IGBT) as controllable switching devices.

[0004] There are two main technical routes for DC energy dissipation devices: one is a resistor centralized energy dissipation device. The other is a resistor distributed energy dissipation device. A centralized energy dissipation device concentrates the energy dissipation resistors on both sides of the inter-electrode and arranges them outside the valve hall in actual applications. The energy dissipation resistors meet the requirements of natural cooling. A distributed energy dissipation device distributes the energy dissipation resistors in each module between the poles, and the cooling of the energy dissipation resistors requires a water cooling device.

[0005] The flexible chopping DC energy dissipation device is a modular DC energy dissipation device based on fully controlled devices. Its basic principle is to use current flexible chopping to achieve the consumption of surplus power on concentrated resistors.

[0006] Existing DC energy dissipation devices mainly use reactors as protection elements to suppress surge currents. The reactor parameters only need to be determined according to the protection requirements, and the design method is relatively simple. However, the reactor of the flexible chopper DC energy dissipation device is a key element for limiting the current change rate (di / dt) of the device switching and reducing the DC voltage ripple. How to design the electrical parameters of the current limiting reactor of the flexible chopper DC energy dissipation device has become an urgent problem to be solved. Summary of the invention

[0007] The embodiments of the present disclosure provide a method for designing electrical parameters of a current limiting reactor of a DC energy consumption device to solve or alleviate one or more of the above technical problems in the prior art.

[0008] According to one aspect of the present disclosure, a method for designing electrical parameters of a current limiting reactor of a DC energy consumption device is provided, comprising:

[0009] Determine a current change rate reference value k;

[0010] Obtain the average current change rate r of the main circuit of the energy consumption device during the conduction of the switch module 1 and the instantaneous rate of change of current r 2 ;

[0011] According to the current change rate reference value k, the current average change rate r 1 and the instantaneous rate of change of current r 2 , calculate the range of the inductance value of the current limiting reactor;

[0012] The switch module shutdown process is analyzed, and the target inductance value of the current limiting reactor is calculated based on the range of the inductance value of the current limiting reactor.

[0013] In a possible implementation, the average current change rate r of the main circuit of the energy consumption device during the conduction of the switch module is obtained. 1 and the instantaneous rate of change of current r 2 include:

[0014] Get the rated current value I of the main circuit of the energy consumption device during the conduction of the switch module DC , and the current of the main circuit of the energy-consuming device rises to the rated current value I DC The total duration T;

[0015] According to the total time T and rated current value I DC Calculate the average current change rate r of the main circuit of the energy consuming device 1 ;

[0016] According to the reactor voltage U L and the inductance value of the reactor L f Calculate the instantaneous rate of change of current r in the main circuit of the energy-consuming device 2 .

[0017] In a possible implementation, according to the current change rate reference value k, the current average change rate r 1 and the instantaneous rate of change of current r 2 , the range of calculating the inductance value of the current limiting reactor includes:

[0018] According to the average current change rate r 1 And the current change rate reference value k, the lower limit of the current limiting reactor inductance value range is calculated to be U DC Indicates the equivalent DC bus voltage;

[0019] According to the instantaneous rate of change of current r 2And the current change rate reference value k, the upper limit of the current limiting reactor inductance range is calculated to be U DC Indicates the equivalent DC bus voltage.

[0020] In a possible implementation, the instantaneous rate of change of current r 2 And the current change rate reference value k, the upper limit of the inductance range of the current limiting reactor is calculated including:

[0021] Take the instantaneous rate of change of current r when the switch module is turned on 2 Calculate the upper limit of the inductance range of the current limiting reactor;

[0022] When the switch module is turned on, the current limiting reactor voltage U L Equal to the equivalent DC bus voltage U DC , then the instantaneous rate of change Among them, L f and L both represent the inductance value of the reactor;

[0023] According to the current change rate reference value k and the instantaneous current change rate r at the time when the switch module is turned on 2 , based on U DC =I DC R, determine the upper limit of the current limiting reactor inductance L range R represents the resistance value of the main circuit of the energy consuming device.

[0024] In a possible implementation, the rated current value I of the main circuit of the energy consumption device during the conduction of the switch module is obtained. DC , and the current of the main circuit of the energy-consuming device rises to the rated current value I DC The total duration T includes:

[0025] Obtaining a steady-state current value of an energy-consuming device;

[0026] When the switch module is turned on, the current value of the main circuit of the energy-consuming device is obtained;

[0027] Calculate the error value between the steady-state current value of the energy-consuming device and the main circuit current value of the energy-consuming device during the conduction process of the switch module;

[0028] Determining whether the error value is reduced to below an error reference value;

[0029] Obtain the main circuit current value of the energy consuming device when the error value is reduced to below the error reference value, and record it as the rated current value;

[0030] The time when the error value is reduced to below the error reference value is obtained, and is recorded as the total time T for the main circuit current value of the energy consumption device to rise to the rated current value.

[0031] In a possible implementation, analyzing the switch module shutdown process, and calculating the target inductance value of the current limiting reactor based on the range of the inductance value of the current limiting reactor includes:

[0032] During the shutdown process of the switch module, the current of the main circuit of the energy-consuming device changes from the rated current value I DC Reduced to 0, the energy consumption device is equivalent to a second-order RLC series circuit, with an equivalent module voltage U Ra As the main state quantity, the KVL equation of the equivalent second-order RLC series circuit is derived:

[0033]

[0034] In the formula, L represents the inductance of the reactor; n represents the number of submodules; Cs represents the capacitance of the submodule; R represents the resistance in the submodule; u Ra represents the voltage of all submodules, t represents time; U DC Indicates the equivalent DC bus voltage;

[0035] Calculate the main circuit current I of the energy consuming device:

[0036]

[0037] Where Cs represents the capacitance value of the submodule; u Ra represents the voltage of all submodules; n represents the number of submodules; t represents time;

[0038] Based on the analytical formula of the KVL equation, the transient process of the switch module during shutdown is analyzed, and the average current change rate r corresponding to different inductance values ​​within the inductance range of the current limiting reactor is calculated. 1 and the instantaneous rate of change of current r 2 , and draw the curve;

[0039] The target inductance value of the current limiting reactor is determined according to the curve.

[0040] According to one aspect of the present disclosure, a system for designing electrical parameters of a current limiting reactor of a DC energy consumption device is provided, comprising:

[0041] A determination unit, used to determine a current change rate reference value k;

[0042] The acquisition unit is used to obtain the average current change rate r of the main circuit of the energy consumption device during the conduction of the switch module. 1 and the instantaneous rate of change of current r 2 ;

[0043] The first calculation unit uses the current change rate reference value k and the current average change rate r 1 and the instantaneous rate of change of current r 2, calculate the range of the inductance value of the current limiting reactor;

[0044] The second calculation unit calculates a target inductance value of the current limiting reactor based on a range of the inductance value of the current limiting reactor by analyzing the shutdown process of the switch module.

[0045] In a possible implementation, the acquiring unit includes:

[0046] The acquisition module is used to obtain the rated current value I of the main circuit of the energy consumption device during the conduction of the switch module. DC , and the current of the main circuit of the energy-consuming device rises to the rated current value I DC The total duration T;

[0047] The first calculation module is used to calculate the total time T and the rated current value I DC Calculate the average current change rate r of the main circuit of the energy consuming device 1 ;

[0048] The second calculation module is used to calculate the voltage U L and the inductance value of the reactor L f Calculate the instantaneous rate of change of current r in the main circuit of the energy-consuming device 2 .

[0049] In a possible implementation, the first computing unit includes:

[0050] The third calculation module is used to calculate the average current change rate r 1 And the current change rate reference value k, the lower limit of the current limiting reactor inductance value range is calculated to be U DC Indicates the equivalent DC bus voltage;

[0051] The fourth calculation module is used to calculate the instantaneous change rate r of the current 2 And the current change rate reference value k, the upper limit of the current limiting reactor inductance range is calculated to be U DC Indicates the equivalent DC bus voltage.

[0052] In a possible implementation, the fourth calculation module includes:

[0053] The value-taking submodule is used to obtain the instantaneous rate of change of the current when the switch module is turned on. 2 Calculate the upper limit of the inductance range of the current limiting reactor;

[0054] When the switch module is turned on, the current limiting reactor voltage U L Equal to the equivalent DC bus voltage U DC , then the instantaneous rate of change Among them, L fand L both represent the inductance value of the reactor;

[0055] The determination submodule is used to determine the instantaneous current change rate r at the time when the switch module is turned on according to the current change rate reference value k 2 , based on U DC =I DC R, determine the upper limit of the current limiting reactor inductance L range R represents the resistance value of the main circuit of the energy consuming device.

[0056] In a possible implementation, the acquisition module includes:

[0057] A first acquisition submodule is used to acquire a steady-state current value of an energy-consuming device;

[0058] The second acquisition submodule is used to obtain the current value of the main circuit of the energy consuming device when the switch module is turned on;

[0059] A calculation submodule, used to calculate the error value between the steady-state current value of the energy-consuming device and the main circuit current value of the energy-consuming device during the conduction process of the switch module;

[0060] A judging submodule, used to judge whether the error value is reduced below an error reference value;

[0061] The third acquisition submodule is used to obtain the main circuit current value of the energy consumption device when the error value is reduced to below the error reference value, and record it as the rated current value;

[0062] The fourth acquisition submodule is used to obtain the time when the error value decreases to below the error reference value, which is recorded as the total time T for the main circuit current value of the energy consumption device to rise to the rated current value.

[0063] In a possible implementation manner, the second computing unit includes:

[0064] The output module, when the switch module is turned off, the current of the main circuit of the energy consumption device changes from the rated current value I DC Reduced to 0, the energy consumption device is equivalent to a second-order RLC series circuit, and the export module is used to obtain the equivalent module voltage U Ra As the main state quantity, the KVL equation of the equivalent second-order RLC series circuit is derived:

[0065]

[0066] In the formula, L represents the inductance of the reactor; n represents the number of submodules; Cs represents the capacitance of the submodule; R represents the resistance in the submodule; u Ra represents the voltage of all submodules, t represents time; U DC Indicates the equivalent DC bus voltage;

[0067] The fifth calculation module is used to calculate the main circuit current I of the energy consumption device:

[0068]

[0069] Where Cs represents the capacitance value of the submodule; u Ra represents the voltage of all submodules; n represents the number of submodules; t represents time;

[0070] Drawing module, used to analyze the transient process of the switch module when it is turned off based on the analytical formula of the KVL equation, and calculate the average current change rate r corresponding to different inductance values ​​within the inductance range of the current limiting reactor 1 and the instantaneous rate of change of current r 2 , and draw the curve;

[0071] A determination module is used to determine a target inductance value of the current-limiting reactor according to the curve.

[0072] According to one aspect of the present disclosure, an application of a method for designing electrical parameters of a current limiting reactor of a DC energy dissipation device is provided, comprising: applying the above-mentioned method for designing electrical parameters of a current limiting reactor of a DC energy dissipation device to a flexible DC power transmission system.

[0073] According to one aspect of the present disclosure, a device for designing electrical parameters of a current-limiting reactor of a flexible chopper-type DC energy dissipation device is provided, comprising:

[0074] Processor and memory;

[0075] The memory is used to store a computer program, and the processor calls the computer program stored in the memory to execute any one of the above methods for designing electrical parameters of a current-limiting reactor of a DC energy consumption device.

[0076] According to one aspect of the present disclosure, a computer-readable storage medium is provided, in which a computer program is stored. When the computer program is executed by a processor, the processor is enabled to execute any of the above-mentioned methods for designing electrical parameters of a current-limiting reactor of a DC energy consumption device.

[0077] The exemplary embodiments of the present disclosure have the following beneficial effects: the exemplary embodiments of the present disclosure determine the specific parameters of the current limiting reactor according to the working characteristics of the flexible chopper type DC energy dissipation device, thereby solving the problem in the prior art that it is difficult to design the electrical parameters of the current limiting reactor of the flexible chopper type DC energy dissipation device; moreover, the design method of the specific parameters of the current limiting reactor proposed in the exemplary embodiments of the present disclosure is applied to the flexible DC transmission system, which can effectively ensure the safe operation of the ultra-high / ultra-high voltage flexible transmission system.

[0078] The details of one or more embodiments of the present application are presented in the following drawings and descriptions. Other features and advantages of the present application will become apparent from the accompanying drawings. It should be understood that the above general description and the detailed descriptions below are only exemplary and explanatory and cannot limit the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification are used to explain the principles of the present disclosure. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0080] Figure 1 is a flow chart of a method for designing electrical parameters of a current limiting reactor of a DC energy consumption device according to the exemplary embodiment;

[0081] Figure 2 is a topological diagram of a modular DC energy consumption device of this exemplary embodiment;

[0082] Figure 3 It is one of the schematic diagrams of the working process of the energy consumption device of this exemplary embodiment;

[0083] Figure 4 This is the second schematic diagram of the working process of the energy consumption device of this exemplary embodiment;

[0084] Figure 5 is a schematic diagram of di / dt value curves corresponding to different inductance values ​​calculated and output by the MATLAB script of this exemplary embodiment;

[0085] Figure 6 is a schematic diagram of a flexible direct current transmission system of this exemplary embodiment;

[0086] Figure 7 is a block diagram of an electrical parameter design system for a current limiting reactor of a DC energy consumption device according to the exemplary embodiment;

[0087] Figure 8 It is a structural schematic diagram of an electrical parameter design device for a current limiting reactor of a DC energy consumption device of the exemplary embodiment. DETAILED DESCRIPTION

[0088] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as being limited to the examples set forth herein; on the contrary, these embodiments are provided so that the present disclosure will be more comprehensive and complete, and the concepts of the example embodiments are fully conveyed to those skilled in the art. The described features, structures, or characteristics may be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced while omitting one or more of the specific details, or other methods, components, devices, steps, etc. may be adopted. In other cases, known technical solutions are not shown or described in detail to avoid obscuring various aspects of the present disclosure.

[0089] In addition, the accompanying drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted. Some of the block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software form, or implemented in one or more hardware units or integrated circuits, or implemented in different networks and / or processor devices and / or microcontroller devices.

[0090] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the steps. For example, some steps may be decomposed, while some steps may be combined or partially combined, so the actual execution order may change according to the actual situation.

[0091] The terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example.

[0092] In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or sub-modules is not necessarily limited to those steps or sub-modules explicitly listed, but may include other steps or sub-modules not explicitly listed or inherent to these processes, methods, products, or apparatuses.

[0093] Figure 1 is a flow chart of a method for designing electrical parameters of a current limiting reactor of a DC energy consumption device according to the exemplary embodiment of the present invention. Figure 1As shown, an exemplary embodiment of the present disclosure provides a method for designing electrical parameters of a current limiting reactor of a DC energy consumption device, comprising the following:

[0094] S1 determines the current change rate reference value k;

[0095] S2 obtains the average current change rate r of the main circuit of the energy consumption device during the conduction of the switch module 1 and the instantaneous rate of change of current r 2 ;

[0096] S3 is based on the current change rate reference value k and the current average change rate r 1 and the instantaneous rate of change of current r 2 , calculate the range of the inductance value of the current limiting reactor;

[0097] S4 analyzes the switch module shutdown process and calculates the target inductance value of the current limiting reactor based on the range of the inductance value of the current limiting reactor.

[0098] It is worth noting that the DC energy dissipation device is composed of a main circuit of the energy dissipation device; the main circuit of the energy dissipation device includes: a number of switch modules, a resistor R 1 , resistor R 2 、Reactor L 1 And the reactor L 2 ; Several switch modules, resistor R 1 , resistor R 2 、Reactor L 1 And the reactor L 2 The switch module includes a fully controlled device K m 、Diode D r , resistor R d , resistor R a 、Diode D f and capacitor C a .

[0099] like Figure 2 As shown, modules SM-1, SM-2...SM-N and R 1 , R 2 , L 1 and L 2 They are connected in series to form the main circuit of the flexible chopper DC energy dissipation device. The fully controlled device (IGCT is used as an example in this embodiment) can accurately control the opening and closing of the module, thereby controlling the on and off of the main circuit current. By adjusting the duty cycle, the on and off time of the module can be controlled to achieve the purpose of flexible control. 1 and R 2 It is called concentrated DC energy dissipation resistor, and its main function is to convert energy from electrical energy to thermal energy, thereby achieving the purpose of suppressing the increase of DC transmission line voltage. 1and L 2 The main function of using a large reactor is to suppress the rate of change of current (di / dt) during the IGCT opening and closing process. s and C s The branches form an absorption loop to absorb the energy of the device shutdown process, thereby achieving the purpose of limiting the voltage across the device.

[0100] like Figure 3 ( Figure 2 L 1 and L 2 Merge into Figure 3 Medium 1 , Figure 2 R 1 and R 2 Merge into Figure 3 Rm) and Figure 4 ( Figure 4 The Ca in Figure 3 Cs, Ra in Figure 3 As shown in Rs in the figure, during the operation of the energy dissipation device, the current limiting reactor plays a role in limiting the current change rate di / dt of the main circuit of the device at the moment of module switching on and off, thereby reducing the impact of load switching on the flexible direct current transmission system. dc is the equivalent DC bus voltage, U L is the current limiting reactor voltage, U Ra is the equivalent module voltage. K m It is a fully controlled device IGCT. When it is turned on, module K m When the module is turned on, current flows through the energy-consuming branch, and the current mainly flows through the IGCT; when the control module is turned off, the current cannot be directly reduced to zero. During the transient shutdown process, the current is absorbed by the absorption branch Cs, thereby absorbing the inductor (reactor) energy and limiting the module voltage. Therefore, the electrical parameter design method of the current limiting reactor is divided into three steps: 1. Determine the design reference di / dt value; 2. Analyze the module conduction process and determine the inductance value range of the current limiting reactor; 3. Analyze the module shutdown process, finally select the inductance value of the current limiting reactor, and design other secondary parameters based on the inductance value.

[0101] For determining the design reference di / dt value: the reference di / dt value is positively correlated with the amplitude of the high-frequency oscillation of the DC system voltage when the switch module of the DC energy consumption device is actuated. Since the voltage level, grid structure, system capacity, etc. of actual projects are different, the design reference di / dt value needs to be determined based on the system simulation results and combined with existing engineering experience. For example, for a ±500kV DC system, the design reference di / dt value is set to 2000A / 3ms. After a reasonable control system design, the DC bus voltage fluctuation can basically be guaranteed to be below ±6%.

[0102] Specifically, S2 obtains the average current change rate r of the main circuit of the energy consumption device during the conduction of the switch module. 1 and the instantaneous rate of change of current r 2 include:

[0103] S21 obtains the rated current value I of the main circuit of the energy consumption device during the conduction of the switch module DC , and the current of the main circuit of the energy-consuming device rises to the rated current value I DC The total time length T, T = 3τ = 3L / R, τ represents the time constant, L is Figure 4 Medium 1 The inductance value, R is Figure 4 Medium R m Resistance value;

[0104] S22 is based on the total duration T and rated current value I DC Calculate the average current change rate r of the main circuit of the energy consuming device 1 ,

[0105] S23 according to the reactor voltage U L and the inductance value of the reactor L f Calculate the instantaneous rate of change of current r in the main circuit of the energy-consuming device 2 .

[0106] Specifically, S3 is based on the current change rate reference value k, the current average change rate r 1 and the instantaneous rate of change of current r 2 , the range of calculating the inductance value of the current limiting reactor includes:

[0107] S31 is based on the average current change rate r 1 And the current change rate reference value k, calculate the lower limit of the current limiting reactor inductance value range

[0108] S32 is based on the instantaneous rate of change of current r 2 And the current change rate reference value k, calculate the upper limit of the inductance range of the current limiting reactor

[0109] Specifically, S32 is based on the instantaneous change rate r of the current. 2 And the current change rate reference value k, calculate the upper limit of the inductance range of the current limiting reactor include:

[0110] Take the instantaneous rate of change of current r when the switch module is turned on 2 Calculate the upper limit of the inductance range of the current limiting reactor;

[0111] When the switch module is turned on, the current limiting reactor voltage U LEqual to the equivalent DC bus voltage U DC , then the instantaneous rate of change Among them, L f and L both represent the inductance value of the reactor;

[0112] According to the current change rate reference value k and the instantaneous current change rate r at the time when the switch module is turned on 2 , based on U DC =I DC R, determine the upper limit of the current limiting reactor inductance L range

[0113] Specifically, S21 obtains the rated current value I of the main circuit of the energy consumption device during the conduction of the switch module. DC , and the current of the main circuit of the energy-consuming device rises to the rated current value I DC The total duration T includes:

[0114] S211 obtains the steady-state current value of the energy consumption device;

[0115] During the conduction process of the S212 switch module, the current value of the main circuit of the energy consumption device is obtained;

[0116] S213 calculates the error value between the steady-state current value of the energy-consuming device and the main circuit current value of the energy-consuming device during the conduction process of the switch module;

[0117] S214 determines whether the error value is reduced to below the error reference value;

[0118] S215 obtains the current value of the main circuit of the energy consumption device when the error value decreases to below the error reference value, and records it as the rated current value;

[0119] S215 obtains the time when the error value decreases to below the error reference value, which is recorded as the total time T for the main circuit current value of the energy consumption device to rise to the rated current value.

[0120] like Figure 3 As shown in the figure, for the analysis module conduction process, the step of determining the inductance range of the current limiting reactor is:

[0121] In the flexible chopper type DC energy dissipation device, the equivalent circuit of the module conduction process is a first-order RL series circuit, and the absolute value of di / dt presents the characteristic of "high at the beginning and low at the end", that is, the absolute value of di / dt is the largest when the module is just turned on, and then gradually decreases and the rate of change slows down. Therefore, when selecting and designing the reactor, the reactor value should not only be selected according to the average rate of change of the current during the module conduction process, but also the instantaneous rate of change of the current should be considered to avoid unexpected switching shocks.

[0122] During the module conduction process, the current in the main circuit of the energy consumption device increases from near 0 to the rated current ID C. At this time, the device is equivalent to a first-order RL series circuit, and the time constant is It is generally believed that after 3τ, the error between the current and the steady-state value is reduced to e -3 × 100% = 5% or less, the current rising process is considered to be over, so the average change rate of the current is Instantaneous rate of change of current When the energy-consuming valve is just opened, U L =U DC , at this time the instantaneous rate of change is the largest, Note that the design reference di / dt value is k. DC =I DC R, so according to the average rate of change and instantaneous rate of change, the appropriate value of L is to Therefore, the design reference di / dt value falls between the average rate of change and the instantaneous rate of change, balancing performance and cost. For example, for a ±500kV / 2000MW flexible DC system, it can be calculated that the range of L is 500mH to 1500mH, that is, the inductance range of a single reactor is 250mH to 750mH.

[0123] Specifically, the S4 analyzes the switch module shutdown process, and calculates the target inductance value of the current limiting reactor based on the range of the inductance value of the current limiting reactor, including:

[0124] During the shutdown process of the switch module, the current of the main circuit of the energy-consuming device changes from the rated current value I DC Reduced to 0, the energy consumption device is equivalent to a second-order RLC series circuit, with an equivalent module voltage U Ra As the main state quantity, the KVL equation of the equivalent second-order RLC series circuit is derived:

[0125]

[0126] Where, L represents the inductance of the reactor; n represents the number of submodules; C s represents the capacitance value of the submodule; R represents the resistance value in the submodule; u Ra represents the voltage of all submodules, t represents time; U DC Indicates the equivalent DC bus voltage;

[0127] Calculate the main circuit current I of the energy consuming device:

[0128]

[0129] In the formula, C s Indicates the capacitance value of the submodule; u Rarepresents the voltage of all submodules; n represents the number of submodules; t represents time;

[0130] Based on the analytical formula of the KVL equation, the transient process of the switch module during shutdown is analyzed, and the average current change rate r corresponding to different inductance values ​​within the inductance range of the current limiting reactor is calculated. 1 and the instantaneous rate of change of current r 2 , and draw a curve; determine the target inductance value of the current limiting reactor according to the curve.

[0131] like Figure 4 As shown in the figure, during the module shutdown process, the current of the energy consumption branch changes from the rated current I DC Reduced to near 0, the device is equivalent to a second-order RLC series circuit. Since the voltage across the reactor continues to decrease as the energy-consuming valve module capacitor is charged, the absolute value of di / dt still presents the characteristic of "high at the beginning and low at the end". Ra As the main state quantity, the KVL equation of the equivalent circuit can be derived:

[0132]

[0133] Where, L represents the inductance of the reactor; n represents the number of submodules; C s represents the capacitance value of the submodule; R represents the resistance value in the submodule; u Ra represents the voltage of all submodules, t represents time; U DC Indicates the equivalent DC bus voltage;

[0134] The energy-consuming main circuit current I can be calculated by the following formula:

[0135]

[0136] According to the above two equations, when the energy-consuming main circuit current I is constant, the equivalent module voltage U Ra The larger the current drop rate di / dt is, the larger the current drop rate di / dt is. Therefore, when analyzing the module shutdown process, the equivalent module voltage U Ra Since the KVL equation of the equivalent circuit is a second-order differential equation and is inconvenient to calculate, a MATLAB script can be written to analyze the transient process of the module shutdown action based on the analytical formula of the KVL equation of the equivalent circuit, and the di / dt average value and di / dt instantaneous maximum value under different inductance values ​​can be calculated using the optimization tool and the curve can be drawn.

[0137] When the selected value is greater than 680mH, the rate of change at any time during the entire switching process must be less than 20, which does not meet the economic requirements; when the selected value is less than 400mH, the average rate of change must be greater than 2000A / 3ms, which also does not meet the design requirements. Therefore, the inductance value selection range of a single current limiting reactor of a 500kV / 2000MW flexible chopper DC energy dissipation device can be narrowed to 400~680mH (such as Figure 5 Finally, by combining the system simulation results, economic analysis, electrical performance requirements, and spatial structure design requirements, the inductance parameters of the reactor selected in the project can be determined, and then the electrical parameters such as short-circuit current and insulation performance can be designed.

[0138] In summary, this embodiment analyzes the parameters of the current limiting reactor and proposes a comprehensive design method based on the working characteristics of the flexible chopper type DC energy dissipation device.

[0139] The exemplary embodiment of the present disclosure provides an application of a method for designing electrical parameters of a current-limiting reactor of a DC energy consumption device, comprising: applying the above-mentioned method for designing electrical parameters of a current-limiting reactor of a DC energy consumption device to a Figure 6 In the flexible direct current transmission system shown, the safe operation of the ultra / UHV flexible transmission system is effectively guaranteed.

[0140] In summary, the present invention proposes a parameter design method for a current limiting reactor of a DC energy dissipation device based on a fully controlled device. On the one hand, according to the design principles, the electrical parameter design steps of a flexible chopper DC energy dissipation device are proposed. On the other hand, the design method and calculation formula adopted in each step are proposed, and a calculation program that can analyze the transient process when the module is shut down is given, which effectively simplifies the design process.

[0141] The present invention relates to a method for designing parameters of a current limiting reactor of a DC energy dissipation device based on a fully controlled device, which includes: a step and method for designing parameters of a current limiting reactor of a flexible chopper type DC energy dissipation device and a calculation program suitable for designing a current limiting reactor of a flexible chopper type DC energy dissipation device.

[0142] The present invention provides a parameter design step and method for a current-limiting reactor of a flexible chopper type DC energy dissipation device, including different analysis and design methods corresponding to the switching on and off actions of a power module of the DC energy dissipation device.

[0143] The present invention proposes a calculation program suitable for the design of a current-limiting reactor for a flexible chopper type DC energy dissipation device, which includes an algorithm for analyzing the transient process when the power module of the energy dissipation device is turned off after given system parameters and initial conditions, and calculating and outputting di / dt value curves corresponding to different inductance selection values.

[0144] Figure 7is a block diagram of an electrical parameter design system for a current limiting reactor of a DC energy consumption device according to the exemplary embodiment of the present invention. Figure 7 As shown, an exemplary embodiment of the present disclosure provides an electrical parameter design system for a current limiting reactor of a flexible chopper type DC energy consumption device, comprising:

[0145] A determination unit 10, configured to determine a current change rate reference value k;

[0146] The acquisition unit 20 is used to acquire the average current change rate r of the main circuit of the energy consumption device during the conduction of the switch module. 1 and the instantaneous rate of change of current r 2 ;

[0147] The first calculation unit 30 uses the current change rate reference value k and the current average change rate r 1 and the instantaneous rate of change of current r 2 , calculate the range of the inductance value of the current limiting reactor;

[0148] The second calculation unit 40 calculates a target inductance value of the current limiting reactor based on the range of the inductance value of the current limiting reactor by analyzing the switch module turn-off process.

[0149] Specifically, the acquisition unit includes:

[0150] The acquisition module is used to obtain the rated current value I of the main circuit of the energy consumption device during the conduction of the switch module. DC , and the current of the main circuit of the energy-consuming device rises to the rated current value I DC The total duration T;

[0151] The first calculation module is used to calculate the total time T and the rated current value I DC Calculate the average current change rate r of the main circuit of the energy consuming device 1 ;

[0152] The second calculation module is used to calculate the voltage U L and the inductance value of the reactor L f Calculate the instantaneous rate of change of current r in the main circuit of the energy-consuming device 2 .

[0153] Specifically, the first computing unit includes:

[0154] The third calculation module is used to calculate the average current change rate r 1 And the current change rate reference value k, the lower limit of the current limiting reactor inductance value range is calculated to be U DC Indicates the equivalent DC bus voltage;

[0155] The fourth calculation module is used to calculate the instantaneous change rate r of the current 2And the current change rate reference value k, the upper limit of the current limiting reactor inductance range is calculated to be U DC Indicates the equivalent DC bus voltage.

[0156] Specifically, the fourth calculation module includes:

[0157] The value-taking submodule is used to obtain the instantaneous rate of change of the current when the switch module is turned on. 2 Calculate the upper limit of the inductance range of the current limiting reactor;

[0158] When the switch module is turned on, the current limiting reactor voltage U L Equal to the equivalent DC bus voltage U DC , then the instantaneous rate of change Among them, L f and L both represent the inductance value of the reactor;

[0159] The determination submodule is used to determine the instantaneous current change rate r at the time when the switch module is turned on according to the current change rate reference value k 2 , based on U DC =I DC R, determine the upper limit of the current limiting reactor inductance L range R represents the resistance value of the main circuit of the energy consuming device.

[0160] Specifically, the acquisition module includes:

[0161] A first acquisition submodule is used to acquire a steady-state current value of an energy-consuming device;

[0162] The second acquisition submodule is used to obtain the current value of the main circuit of the energy consuming device when the switch module is turned on;

[0163] A calculation submodule, used to calculate the error value between the steady-state current value of the energy-consuming device and the main circuit current value of the energy-consuming device during the conduction process of the switch module;

[0164] A judging submodule, used to judge whether the error value is reduced below an error reference value;

[0165] The third acquisition submodule is used to obtain the main circuit current value of the energy consumption device when the error value is reduced to below the error reference value, and record it as the rated current value;

[0166] The fourth acquisition submodule is used to obtain the time when the error value decreases to below the error reference value, which is recorded as the total time T for the main circuit current value of the energy consumption device to rise to the rated current value.

[0167] Specifically, the second computing unit includes:

[0168] The output module, when the switch module is turned off, the current of the main circuit of the energy consumption device changes from the rated current value I DC Reduced to 0, the energy consumption device is equivalent to a second-order RLC series circuit, and the export module is used to obtain the equivalent module voltage U Ra As the main state quantity, the KVL equation of the equivalent second-order RLC series circuit is derived:

[0169]

[0170] In the formula, L represents the inductance of the reactor; n represents the number of submodules; Cs represents the capacitance of the submodule; R represents the resistance in the submodule; u Ra represents the voltage of all submodules, t represents time; U DC Indicates the equivalent DC bus voltage;

[0171] The fifth calculation module is used to calculate the main circuit current I of the energy consumption device:

[0172]

[0173] Where Cs represents the capacitance value of the submodule; u Ra represents the voltage of all submodules; n represents the number of submodules; t represents time;

[0174] Drawing module, used to analyze the transient process of the switch module when it is turned off based on the analytical formula of the KVL equation, and calculate the average current change rate r corresponding to different inductance values ​​within the inductance range of the current limiting reactor 1 and the instantaneous rate of change of current r 2 , and draw the curve;

[0175] A determination module is used to determine a target inductance value of the current-limiting reactor according to the curve.

[0176] Figure 8 is a schematic diagram of the structure of an electrical parameter design device for a current limiting reactor of a DC energy consumption device according to the exemplary embodiment of the present invention. Figure 8As shown, corresponding to the above-mentioned method for designing electrical parameters of a current-limiting inductor of a DC energy dissipation device, the present invention also provides a device for designing electrical parameters of a current-limiting inductor of a flexible chopper type DC energy dissipation device. Since the embodiment of the device is similar to the above-mentioned method embodiment, the description is relatively simple. For relevant parts, please refer to the description of the above-mentioned method embodiment part. The device described below is only schematic. The device may include: a processor 1, a memory 2, a communication bus (i.e., the above-mentioned device bus) and a search engine, wherein the processor 1 and the memory 2 communicate with each other through the communication bus and communicate with the outside through the communication interface. The processor 1 can call the logic instructions in the memory 2 to execute the method for designing electrical parameters of a current-limiting inductor of a DC energy dissipation device.

[0177] In addition, the logic instructions in the above-mentioned memory 2 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: a storage chip, a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a disk or an optical disk, and other media that can store program codes.

[0178] On the other hand, an embodiment of the present invention further provides a processor-readable storage medium, on which a computer program 3 is stored. When the computer program 3 is executed by the processor 1, the electrical parameter design method of the current limiting inductor of the DC energy consumption device provided in the above embodiments is implemented.

[0179] The processor-readable storage medium can be any available medium or data storage device that can be accessed by the processor 1, including but not limited to magnetic storage (such as floppy disks, hard disks, magnetic tapes, magneto-optical disks (MO), etc.), optical storage (such as CD, DVD, BD, HVD, etc.), and semiconductor storage (such as ROM, EPROM, EEPROM, non-volatile memory (NANDFLASH), solid-state drive (SSD)), etc.

[0180] The above are only preferred implementations of the present disclosure, and the protection scope of the present disclosure is not limited to the above embodiments. All technical solutions under the concept of the present disclosure belong to the protection scope of the present disclosure. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present disclosure should be regarded as the protection scope of the present disclosure.

Claims

1. A method for designing electrical parameters of a current limiting reactor of a DC energy consumption device, characterized in that: include: Determine a current change rate reference value k; Obtain the average current change rate r1 and the instantaneous current change rate r2 of the main circuit of the energy consumption device during the conduction of the switch module; Calculate the range of the inductance value of the current limiting reactor based on the current change rate reference value k, the current average change rate r1 and the current instantaneous change rate r2; The switch module shutdown process is analyzed, and the target inductance value of the current limiting reactor is calculated based on the range of the inductance value of the current limiting reactor.

2. The method for designing electrical parameters of a current limiting reactor of a DC energy consumption device according to claim 1, characterized in that: The average current change rate r1 and the instantaneous current change rate r2 of the main circuit of the energy-consuming device during the conduction of the switch module are obtained by: Get the rated current value I of the main circuit of the energy consumption device during the conduction of the switch module DC , and the current of the main circuit of the energy-consuming device rises to the rated current value I DC The total duration T; According to the total time T and rated current value I DC Calculate the average rate of change of current r1 in the main circuit of the energy-consuming device; According to the reactor voltage U L and the inductance value of the reactor L f Calculate the instantaneous rate of change r2 of current in the main circuit of the energy consuming device.

3. The method for designing electrical parameters of a current limiting reactor of a DC energy consumption device according to claim 1, characterized in that: According to the current change rate reference value k, the current average change rate r1 and the current instantaneous change rate r2, the range of calculating the inductance value of the current limiting reactor includes: According to the average current change rate r1 and the current change rate reference value k, the lower limit of the current limiting reactor inductance value range is calculated to be U DC Indicates the equivalent DC bus voltage; According to the instantaneous current change rate r2 and the current change rate reference value k, the upper limit of the inductance range of the current limiting reactor is calculated to be U DC Indicates the equivalent DC bus voltage.

4. The method for designing electrical parameters of a current limiting reactor of a DC energy consumption device according to claim 3, characterized in that: The calculation of the upper limit of the inductance range of the current limiting reactor according to the instantaneous current change rate r2 and the current change rate reference value k includes: The instantaneous rate of change of current r2 at the time when the switch module is turned on is taken to calculate the upper limit of the inductance range of the current limiting reactor; When the switch module is turned on, the current limiting reactor voltage U L Equal to the equivalent DC bus voltage U DC , then the instantaneous rate of change Among them, L f and L both represent the inductance value of the reactor; According to the current change rate reference value k and the instantaneous current change rate r2 at the time when the switch module is turned on, based on U DC =I DC R, determine the upper limit of the current limiting reactor inductance L range R represents the resistance value of the main circuit of the energy consuming device.

5. The method for designing electrical parameters of a current limiting reactor of a DC energy consumption device according to claim 2, characterized in that: Get the rated current value I of the main circuit of the energy consumption device during the conduction of the switch module DC , and the current of the main circuit of the energy-consuming device rises to the rated current value I DC The total duration T includes: Obtaining a steady-state current value of an energy-consuming device; When the switch module is turned on, the current value of the main circuit of the energy-consuming device is obtained; Calculate the error value between the steady-state current value of the energy-consuming device and the main circuit current value of the energy-consuming device during the conduction process of the switch module; Determining whether the error value is reduced to below an error reference value; Obtain the main circuit current value of the energy consuming device when the error value is reduced to below the error reference value, and record it as the rated current value; The time when the error value is reduced to below the error reference value is obtained, and is recorded as the total time T for the main circuit current value of the energy consumption device to rise to the rated current value.

6. The method for designing electrical parameters of a current limiting reactor of a DC energy consumption device according to claim 1, characterized in that: Analyze the switch module shutdown process and calculate the target inductance value of the current limiting reactor based on the range of the inductance value of the current limiting reactor, including: During the shutdown process of the switch module, the current of the main circuit of the energy-consuming device changes from the rated current value I DC Reduced to 0, the energy consumption device is equivalent to a second-order RLC series circuit, with an equivalent module voltage U Ra As the main state quantity, the KVL equation of the equivalent second-order RLC series circuit is derived: In the formula, L represents the inductance of the reactor; n represents the number of submodules; Cs represents the capacitance of the submodule; R represents the resistance in the submodule; u Ra represents the voltage of all submodules, t represents time; U DC Indicates the equivalent DC bus voltage; Calculate the main circuit current I of the energy consuming device: Where Cs represents the capacitance value of the submodule; u Ra represents the voltage of all submodules; n represents the number of submodules; t represents time; Based on the analytical formula of the KVL equation, the transient process of the switch module during shutdown is analyzed, the average current change rate r1 and the instantaneous current change rate r2 corresponding to different inductance values ​​within the inductance range of the current limiting reactor are calculated, and the curves are drawn; The target inductance value of the current limiting reactor is determined according to the curve.

7. A system for designing electrical parameters of a current limiting reactor of a DC energy consumption device, characterized in that: include: A determination unit, used to determine a current change rate reference value k; An acquisition unit is used to acquire the average current change rate r1 and the instantaneous current change rate r2 of the main circuit of the energy consumption device during the conduction process of the switch module; The first calculation unit calculates the range of the inductance value of the current limiting reactor according to the current change rate reference value k, the current average change rate r1 and the current instantaneous change rate r2; The second calculation unit calculates a target inductance value of the current limiting reactor based on a range of the inductance value of the current limiting reactor by analyzing the shutdown process of the switch module.

8. The electrical parameter design system of a current limiting reactor of a DC energy consumption device according to claim 7, characterized in that: The acquisition unit includes: The acquisition module is used to obtain the rated current value I of the main circuit of the energy consumption device during the conduction of the switch module. DC , and the current of the main circuit of the energy-consuming device rises to the rated current value I DC The total duration T; The first calculation module is used to calculate the total time T and the rated current value I DC Calculate the average rate of change of current r1 in the main circuit of the energy-consuming device; The second calculation module is used to calculate the voltage U L and the inductance value of the reactor L f Calculate the instantaneous rate of change r2 of current in the main circuit of the energy consuming device.

9. The electrical parameter design system of a current limiting reactor of a DC energy consumption device according to claim 7, characterized in that: The first computing unit comprises: The third calculation module is used to calculate the lower limit of the inductance value range of the current limiting reactor according to the average current change rate r1 and the current change rate reference value k. U DC Indicates the equivalent DC bus voltage; The fourth calculation module is used to calculate the upper limit of the inductance value range of the current limiting reactor according to the instantaneous current change rate r2 and the current change rate reference value k. U DC Indicates the equivalent DC bus voltage.

10. The electrical parameter design system of a current limiting reactor of a DC energy consumption device according to claim 9, characterized in that: The fourth calculation module includes: The value-taking submodule is used to take the instantaneous rate of change of the current r2 at the time when the switch module is turned on to calculate the upper limit of the inductance value range of the current-limiting reactor; When the switch module is turned on, the current limiting reactor voltage U L Equal to the equivalent DC bus voltage U DC , then the instantaneous rate of change Among them, L f and L both represent the inductance value of the reactor; The determination submodule is used to determine the current instantaneous change rate r2 based on the current change rate reference value k and the current instantaneous change rate r2 at the time when the switch module is turned on, based on U DC =I DC R, determine the upper limit of the current limiting reactor inductance L range R represents the resistance value of the main circuit of the energy consuming device.

11. The electrical parameter design system of a current limiting reactor of a DC energy consumption device according to claim 8, characterized in that: The acquisition module comprises: A first acquisition submodule is used to acquire a steady-state current value of an energy-consuming device; The second acquisition submodule is used to obtain the current value of the main circuit of the energy consuming device when the switch module is turned on; A calculation submodule, used to calculate the error value between the steady-state current value of the energy-consuming device and the main circuit current value of the energy-consuming device during the conduction process of the switch module; A judging submodule, used to judge whether the error value is reduced below an error reference value; The third acquisition submodule is used to obtain the main circuit current value of the energy consumption device when the error value is reduced to below the error reference value, and record it as the rated current value; The fourth acquisition submodule is used to obtain the time when the error value decreases to below the error reference value, which is recorded as the total time T for the main circuit current value of the energy consumption device to rise to the rated current value.

12. The electrical parameter design system of a current limiting reactor of a DC energy consumption device according to claim 7, characterized in that: The second computing unit comprises: The output module, when the switch module is turned off, the current of the main circuit of the energy consumption device changes from the rated current value I DC Reduced to 0, the energy consumption device is equivalent to a second-order RLC series circuit, and the export module is used to obtain the equivalent module voltage U Ra As the main state quantity, the KVL equation of the equivalent second-order RLC series circuit is derived: In the formula, L represents the inductance of the reactor; n represents the number of submodules; Cs represents the capacitance of the submodule; R represents the resistance in the submodule; u Ra represents the voltage of all submodules, t represents time; U DC Indicates the equivalent DC bus voltage; The fifth calculation module is used to calculate the main circuit current I of the energy consumption device: Where Cs represents the capacitance value of the submodule; u Ra represents the voltage of all submodules; n represents the number of submodules; t represents time; The drawing module is used to analyze the transient process of the switch module when it is turned off based on the analytical formula of the KVL equation, calculate the average current change rate r1 and the instantaneous current change rate r2 corresponding to different inductance values ​​within the inductance value range of the current limiting reactor, and draw the curve; A determination module is used to determine a target inductance value of the current-limiting reactor according to the curve.

13. An application of a method for designing electrical parameters of a current limiting reactor of a DC energy consumption device, characterized in that: include: The electrical parameter design method of the current limiting reactor of the DC energy consumption device described in any one of claims 1 to 7 is applied to a flexible DC power transmission system.

14. An electrical parameter design device for a current limiting reactor of a DC energy consumption device, characterized in that: include: Processor and memory; The memory is used to store a computer program, and the processor calls the computer program stored in the memory to execute the method for designing electrical parameters of a current limiting reactor of a DC energy consumption device according to any one of claims 1 to 6.

15. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the processor is enabled to execute the method for designing electrical parameters of a current-limiting reactor of a DC energy consumption device according to any one of claims 1 to 6.

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