Method and device for reducing power frequency temporary overvoltage of doubly-fed wind turbine generator

Abstract

The invention provides a method and device for reducing power frequency temporary overvoltage of doubly-fed wind turbine generators, and the method comprises the steps: obtaining the generator end transient voltage rise of each doubly-fed wind turbine generator after a fault according to a self-defined sampling interval when a power grid breaks down; in response to a comparison result that the machine end transient voltage rise of any doubly-fed wind turbine generator set at the fault starting moment is greater than a self-defined voltage rise limit value, the proportion of the installed capacity of the doubly-fed wind turbine generator set to which the AC-Copper device is to act in the installed capacity of all doubly-fed wind turbine generator sets is increased; according to the method, the power grid fault ride-through time is shortened, the action voltage value for triggering the AC-chopper device to act is gradually reduced, the action delay time value for triggering the AC-chopper device to act is shortened, it is guaranteed that the transient voltage rise of the generator end is lower than the voltage rise limiting value as soon as possible by rapidly releasing the energy of the doubly-fed wind turbine generator in the power grid fault ride-through period, and safety and stability of the system are effectively maintained.

Description

Technical Field

[0001] The present invention relates to the technical field of ultra-high voltage power transmission, and more specifically, to a method and device for reducing temporary power frequency overvoltage of a doubly-fed wind turbine generator set. Background Art

[0002] With the rapid development of new energy, wind power accounts for an increasing proportion of the entire power grid. Therefore, the power grid has put forward higher requirements for the access of wind turbines. One of the requirements is that wind turbines must have low voltage ride-through capability, that is, after the connected power grid fails and the voltage of the wind farm drops, the wind turbine can ensure uninterrupted grid-connected operation through low voltage ride-through, thereby avoiding the occurrence of failures that seriously affect the stability of the power grid system due to the cut-out of the wind farm. When a low voltage ride-through fault occurs in the power grid, the grid voltage at the wind turbine grid connection point drops, and the energy generated by the wind turbine cannot be sent to the power grid through the unit converter. At the same time, due to the large mechanical inertia characteristics of the wind turbine itself, energy will continue to be sent to the unit converter, resulting in a temporary imbalance in the energy input and output of the unit converter, causing a temporary overvoltage condition at the power frequency. If it is not controlled at this time, it will eventually damage the wind turbine converter. In order to protect the wind turbine converter and realize the low voltage ride-through function, the prior art connects an AC-Chopper device at the connection between the double-fed wind turbine converter and the DC bus, and uses the AC-Chopper device to discharge energy when the bus voltage is too high. However, there is still a lack of effective technical means to accurately discharge energy when a fault occurs in the actual operation of the power grid and a temporary overvoltage occurs in the power frequency of the double-fed wind turbine, so as to maintain the safety and stability of the system voltage. Summary of the invention

[0003] In order to solve the technical problem that there is a lack of effective technical means in the prior art to solve the technical problem of using an AC-Chopper device to accurately discharge energy when a fault occurs in the actual operation of the power grid and a temporary overvoltage of the power frequency of a doubly-fed wind turbine is generated, the present invention provides a method and device for reducing the temporary overvoltage of the power frequency of a doubly-fed wind turbine.

[0004] According to one aspect of the present invention, the present invention provides a method for reducing temporary power frequency overvoltage of a doubly-fed wind turbine generator set, comprising:

[0005] When a fault occurs in the power grid, the transient voltage rise at the machine end of each doubly-fed wind turbine after the fault is obtained according to a custom sampling interval, wherein at least one converter inside the doubly-fed wind turbine is connected to an AC-Chopper device at the DC bus;

[0006] In response to a comparison result that the transient voltage rise at the machine end of any double-fed wind turbine set at the start of a fault is greater than a user-defined voltage rise limit value, a first adjustment is made to the power frequency temporary overvoltage according to the proportion of the installed capacity of the double-fed wind turbine set to be operated by the AC-Chopper device to the installed capacity of all double-fed wind turbine sets;

[0007] In response to the comparison result that the transient voltage rise at the machine end of any doubly-fed wind turbine set is greater than the voltage rise limit value when the first adjustment is performed until the ratio is equal to the user-defined ratio limit value, a second adjustment is performed on the power frequency temporary overvoltage according to the action voltage value of the AC-Chopper device in the doubly-fed wind turbine set of the ratio limit value, wherein the action voltage value is the machine end voltage value that triggers the action of the AC-Chopper device in the doubly-fed wind turbine set;

[0008] In response to the comparison result that the transient voltage rise at the machine end of any doubly-fed wind turbine group is greater than the voltage rise limit value when the second adjustment is performed to the action voltage value not less than the customized action voltage lower limit value, a third adjustment is performed on the power frequency temporary overvoltage according to the action delay time value of the AC-Chopper device in the doubly-fed wind turbine group with the proportional limit value at the action voltage lower limit value.

[0009] A data acquisition module is used to acquire the transient voltage rise at the machine end of each doubly-fed wind turbine after the fault occurs in the power grid according to a custom sampling interval, wherein at least one converter inside the doubly-fed wind turbine is connected to an AC-Chopper device at the DC bus;

[0010] A first regulating module, configured to, in response to a comparison result that the transient voltage rise at the machine end of any double-fed wind turbine set at the start of a fault is greater than a user-defined voltage rise limit value, perform a first regulation on the power frequency temporary overvoltage according to the proportion of the installed capacity of the double-fed wind turbine set to be operated by the AC-Chopper device to the installed capacity of all double-fed wind turbine sets;

[0011] A second regulating module is used for performing a second regulation on the power frequency temporary overvoltage according to the action voltage value of the AC-Chopper device in the doubly-fed wind turbine set of the proportion limit value in response to the comparison result that the transient voltage rise at the machine end of any doubly-fed wind turbine set is greater than the voltage rise limit value when the first regulation is performed until the proportion is equal to the self-defined proportion limit value, wherein the action voltage value is the machine end voltage value that triggers the action of the AC-Chopper device in the doubly-fed wind turbine set;

[0012] The third regulation module is used to respond to the comparison result that the transient voltage rise at the machine end of any double-fed wind turbine group is greater than the voltage rise limit value when the second adjustment is performed to the action voltage value not less than the customized action voltage lower limit value, and perform a third regulation on the power frequency temporary overvoltage according to the action delay time value of the AC-Chopper device in the double-fed wind turbine group of the proportional limit value at the action voltage lower limit value.

[0013] According to another aspect of the present invention, the present invention provides a device for reducing temporary overvoltage of power frequency of a doubly-fed wind turbine generator set, the device comprising:

[0014] A data acquisition module is used to acquire the transient voltage rise at the machine end of each doubly-fed wind turbine after the fault occurs in the power grid according to a custom sampling interval, wherein at least one converter inside the doubly-fed wind turbine is connected to an AC-Chopper device at the DC bus;

[0015] A first regulating module, configured to, in response to a comparison result that the transient voltage rise at the machine end of any double-fed wind turbine set at the start of a fault is greater than a user-defined voltage rise limit value, perform a first regulation on the power frequency temporary overvoltage according to the proportion of the installed capacity of the double-fed wind turbine set to be operated by the AC-Chopper device to the installed capacity of all double-fed wind turbine sets;

[0016] A second regulating module is used for performing a second regulation on the power frequency temporary overvoltage according to the action voltage value of the AC-Chopper device in the doubly-fed wind turbine set of the proportion limit value in response to the comparison result that the transient voltage rise at the machine end of any doubly-fed wind turbine set is greater than the voltage rise limit value when the first regulation is performed until the proportion is equal to the self-defined proportion limit value, wherein the action voltage value is the machine end voltage value that triggers the action of the AC-Chopper device in the doubly-fed wind turbine set;

[0017] The third regulation module is used to respond to the comparison result that the transient voltage rise at the machine end of any double-fed wind turbine group is greater than the voltage rise limit value when the second adjustment is performed to the action voltage value not less than the customized action voltage lower limit value, and perform a third regulation on the power frequency temporary overvoltage according to the action delay time value of the AC-Chopper device in the double-fed wind turbine group of the proportional limit value at the action voltage lower limit value.

[0018] According to another aspect of the present invention, the present invention provides a computer-readable storage medium, wherein the storage medium stores a computer program, and the computer program is used to execute the method described in any one of the above aspects of the present invention.

[0019] According to another aspect of the present invention, an electronic device is provided, comprising: a processor; a memory for storing instructions executable by the processor; the processor is configured to read the executable instructions from the memory and execute the instructions to implement the method described in any one of the above aspects of the present invention.

[0020] The method and device for reducing temporary power frequency overvoltage of a doubly-fed wind turbine set described in the present invention include, when a power grid fault occurs, obtaining the transient voltage rise of each doubly-fed wind turbine set after the fault according to a custom sampling interval, responding to a comparison result that the transient voltage rise of any doubly-fed wind turbine set at the start of the fault is greater than the custom voltage rise limit, increasing the proportion of the installed capacity of the doubly-fed wind turbine set to be acted by the AC-Chopper device to the installed capacity of all doubly-fed wind turbine sets, and gradually reducing the action voltage value that triggers the action of the AC-Chopper device, shortening the action delay time value that triggers the action of the AC-Chopper device, ensuring that the energy of the doubly-fed wind turbine set is quickly discharged during the power grid fault ride-through, ensuring that the transient voltage rise of the machine end is lower than the voltage rise limit as soon as possible, and effectively maintaining the safety and stability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] A more complete understanding of exemplary embodiments of the present invention may be obtained by referring to the following drawings:

[0022] Figure 1 A flowchart of a method for reducing temporary power frequency overvoltage of a doubly-fed wind turbine generator set according to a preferred embodiment of the present invention;

[0023] Figure 2 It is a structural schematic diagram of a device for reducing temporary power frequency overvoltage of a doubly-fed wind turbine generator set according to a preferred embodiment of the present invention;

[0024] Figure 3 Schematic diagram of the structure of an electronic device according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0025] Now, exemplary embodiments of the present invention are described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely and to fully convey the scope of the present invention to those skilled in the art. The terms used in the exemplary embodiments shown in the accompanying drawings are not intended to limit the present invention. In the accompanying drawings, the same units / elements are marked with the same reference numerals.

[0026] Unless otherwise specified, the terms (including technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is understood that the terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0027] Exemplary Methods

[0028] Figure 1 Flow chart of a method for reducing temporary overvoltage of power frequency of a doubly-fed wind turbine generator set according to a preferred embodiment of the present invention. Figure 1 As shown, the method for reducing temporary power frequency overvoltage of a doubly-fed wind turbine generator system described in this preferred embodiment starts from step 101.

[0029] In step 101, when a power grid fault occurs, a transient voltage rise at the machine end of each doubly-fed wind turbine after the fault is obtained according to a custom sampling interval, wherein a converter inside at least one doubly-fed wind turbine is connected to an AC-Chopper device at the DC bus.

[0030] In this preferred embodiment, in order to protect the wind turbine converter and realize the low voltage ride-through function, at the same time, from the perspective of reducing costs, an AC-Chopper device is connected to the connection between the converter and the DC bus of a certain proportion of the double-fed wind turbines. The proportion limit can be determined based on experience, and in this preferred embodiment it is 50%. When the power grid has AC N-1, N-2 and DC blocking, restart and commutation failure and other faults, the transient voltage rise at the machine end of each double-fed wind turbine is collected. In this preferred embodiment, the transient voltage rise of a certain double-fed wind turbine collected at the beginning of the fault is 0.43pu.

[0031] In step 102, in response to a comparison result that the transient voltage rise at the machine end of any doubly-fed wind turbine set at the start of a fault is greater than a user-defined voltage rise limit, a first adjustment is made to the power frequency temporary overvoltage according to the ratio of the installed capacity of the doubly-fed wind turbine set to be activated by the AC-Chopper device to the installed capacity of all doubly-fed wind turbine sets.

[0032] Preferably, the first adjustment of the power frequency temporary overvoltage is performed according to the ratio of the installed capacity of the doubly-fed wind turbine set to be operated by the AC-Chopper device to the installed capacity of all doubly-fed wind turbine sets, wherein the first adjustment comprises:

[0033] Step 2-1, according to the customized initial value P0 and step length P S Calculate the proportion P of the installed capacity of the doubly-fed wind turbine generator set that the AC-Chopper device is supposed to operate in the i-th adjustment to the installed capacity of all doubly-fed wind turbine generator sets i, and its calculation formula is:

[0034] P i =P0+(i-1)×P S

[0035] Where i is a positive integer, P0 and P S All are positive numbers less than 1;

[0036] Step 2-2, when P i <P max When the ratio P i After the AC-Chopper device that meets the initial action conditions in the AC-Chopper device of the doubly-fed wind turbine sets is actuated, the transient voltage rise at the machine end of each doubly-fed wind turbine set is obtained. Otherwise, determine the proportion P max The AC-Chopper device in the double-fed wind turbine generator system enters the second regulation, and the first regulation ends, wherein the initial action condition is that the action voltage value of the AC-Chopper device is not less than the user-defined action voltage initial value, and the action delay time value is equal to the user-defined action delay time initial value, P max is a custom scale limit;

[0037] Step 2-3: When the transient voltage rise at the terminal of any doubly-fed wind turbine generator meets the following conditions: , let i=i+1, and return to step 2-1, otherwise, the first adjustment ends, where ΔU max It is a user-defined voltage rise limit.

[0038] In this preferred embodiment, the custom pressure rise limit is 0.3pu, and the proportional limit P max is 50%. Since there is a comparison result that the transient voltage rise of 0.43pu at the machine end is greater than 0.3pu, it is determined that the double-fed wind turbine generator set has a temporary power frequency overvoltage problem after the fault. Therefore, it is necessary to use the first adjustment to suppress the temporary power frequency overvoltage. Assume that the customized initial value of the ratio P0 is 20%, and the proportional step length P Sis 5%, then the proportion of the installed capacity of the doubly fed wind turbine units that the AC-Chopper device is intended to act on to the total installed capacity of the doubly fed wind turbine units in the power grid starts from 20% and increases in steps of 5%. Each time the AC-Chopper device that meets the initial action conditions discharges energy, the transient voltage rise at the machine end of each doubly fed wind turbine unit is obtained again. If it is still greater than the voltage rise limit, the proportion is continued to be increased in steps of 5% until the proportion of the installed capacity of the doubly fed wind turbine units that the AC-Chopper device is intended to act on to the total installed capacity of the doubly fed wind turbine units in the power grid reaches the proportion limit of 50%. When the transient voltage rise at the machine end of the doubly fed wind turbine units obtained after the AC-Chopper device that meets the initial action conditions discharges energy is still 0.33pu, the second adjustment is required because it exceeds the voltage rise limit of 0.3pu.

[0039] In step 103, in response to a comparison result that the transient voltage rise at the machine end of any doubly-fed wind turbine set is greater than the voltage rise limit value when the first adjustment is performed to the ratio being equal to the custom ratio limit value, a second adjustment is performed on the power frequency temporary overvoltage according to the action voltage value of the AC-Chopper device in the doubly-fed wind turbine set of the ratio limit value, wherein the action voltage value is the machine end voltage value that triggers the action of the AC-Chopper device in the doubly-fed wind turbine set.

[0040] Preferably, the second adjustment is performed on the temporary power frequency overvoltage according to the action voltage value of the AC-Chopper device in the doubly-fed wind turbine set according to the proportional limit value, wherein the second adjustment includes:

[0041] Step 3-1: According to the customized action voltage initial value U0 and voltage step length U S Calculate the action voltage value U of the AC-Chopper device in the double-fed wind turbine set with the ratio limit at the jth adjustment j , and its calculation formula is:

[0042] U j =U0-j×U S

[0043] Where j is a positive integer, U0>U S , U S is a positive number less than 1;

[0044] Step 3-2, when U j ≥U min When the voltage at the terminal of the doubly-fed wind turbine generator set is no less than U j After the AC-Chopper device of the doubly-fed wind turbine is activated, the transient voltage rise at the machine end of each doubly-fed wind turbine is obtained. Otherwise, the second adjustment ends, where Umin It is the user-defined lower limit of the action voltage;

[0045] Step 3-3, when the transient voltage at the terminal of any doubly-fed wind turbine generator set meets When , set j=j+1 and return to step 3-1; otherwise, the second adjustment ends.

[0046] In this preferred embodiment, the user-defined initial action voltage value U0 is 1.1pu, the lower limit of the action voltage is 1.0pu, and the voltage step is 0.01pu. When the proportion of the installed capacity of the doubly-fed wind turbine units that the AC-Chopper device intends to act on has reached the proportion limit of 50% of all doubly-fed wind turbine units, but after the AC-Chopper device that meets the initial action conditions is actuated, it still cannot suppress the temporary overvoltage of the power frequency of the unit, and the adjustment can only be continued by changing the action conditions of the AC-Chopper device. Therefore, during the second adjustment, the action voltage value is mainly reduced from the initial action voltage value of 1.1pu to a step size of 0.01pu, so that the AC-Chopper devices in the doubly-fed wind turbine units that account for 50% have more trigger actions to discharge energy to reduce the transient voltage rise at the machine end. In this preferred embodiment, when the action voltage value drops to 1.04pu, the maximum machine-end transient voltage rise of all doubly-fed wind turbines in the power grid also drops to 0.295pu, which is within the voltage rise limit of 0.3pu. That is, when the installed capacity of the doubly-fed wind turbines to be acted upon by the AC-Chopper device accounts for 50% of the capacity of all wind turbines, and the action voltage value that triggers the action of the AC-Chopper device is 1.04pu, the action is performed according to the initial value of the action delay time, thereby avoiding the problem of temporary power frequency overvoltage in all doubly-fed wind turbines after a fault, and thus there is no need to shorten the action delay time that triggers the action of the AC-Chopper device through the third adjustment to suppress temporary power frequency overvoltage.

[0047] In step 104, in response to the comparison result that the transient voltage rise at the machine end of any doubly fed wind turbine group is greater than the voltage rise limit value when the second adjustment is performed to the action voltage value not less than the customized action voltage lower limit value, a third adjustment is performed on the power frequency temporary overvoltage according to the action delay time value of the AC-Chopper device in the doubly fed wind turbine group with the proportional limit value at the action voltage lower limit value.

[0048] Preferably, the third adjustment is performed on the power frequency temporary overvoltage according to the action delay time value of the AC-Chopper device in action, wherein the third adjustment comprises:

[0049] Step 4-1, according to the customized action delay time initial value T0 and time step T SCalculate the action delay time value T of the AC-Chopper device in the double-fed wind turbine generator set with the proportional limit value during the kth adjustment, so that the action voltage value is not less than the user-defined action voltage lower limit value. k , and its calculation formula is:

[0050] T k =T0-k×T S

[0051] Where k is a positive integer, T0>T S , T S is a positive number;

[0052] Step 4-2, when T k >0, in the double-fed wind turbine generator set with the ratio limit, the action voltage value is not less than the user-defined action voltage lower limit value, and the action delay time is T k After the AC-Chopper device is activated, the transient voltage rise at the machine end of each doubly fed wind turbine is obtained. Otherwise, the third adjustment ends;

[0053] Step 4-3, when the transient voltage at the terminal of any doubly-fed wind turbine generator set meets When k=k+1, return to step 4-1; otherwise, the third adjustment ends.

[0054] In this preferred embodiment, the action delay time initial value T0 and the time step T S They are 250ms and 10ms respectively. When adjusting the action delay time, shorten it gradually in steps of 10ms, but it must not be less than 0.

[0055] The method for reducing temporary overvoltage at the power frequency of the doubly-fed wind turbine set described in the preferred embodiment adopts the method of increasing the proportion of the installed capacity of the doubly-fed wind turbine set for which the AC-Chopper device is to be actuated to the installed capacity of all doubly-fed wind turbine sets, and gradually reducing the action voltage value that triggers the action of the AC-Chopper device, and shortening the action delay time value that triggers the action of the AC-Chopper device, so as to ensure that the energy of the doubly-fed wind turbine set is quickly discharged during the grid fault ride-through, so as to ensure that the transient voltage rise at the machine end is lower than the voltage rise limit as soon as possible, thereby effectively maintaining the safety and stability of the system.

[0056] Exemplary Devices

[0057] Figure 2 Schematic diagram of the structure of a device for reducing temporary overvoltage of a double-fed wind turbine generator system according to a preferred embodiment of the present invention. Figure 2 As shown, the device 200 for reducing temporary overvoltage of a doubly-fed wind turbine generator system according to this preferred embodiment includes:

[0058] The data acquisition module 201 is used to acquire the transient voltage rise of each doubly-fed wind turbine after the fault according to a user-defined sampling interval when a fault occurs in the power grid, wherein the converter inside at least one doubly-fed wind turbine is connected to an AC-Chopper device at the DC bus;

[0059] The first regulating module 202 is used for, in response to the comparison result that the transient voltage rise at the machine end of any double-fed wind turbine set at the start of the fault is greater than the self-defined voltage rise limit value, performing a first regulation on the temporary power frequency overvoltage according to the proportion of the installed capacity of the double-fed wind turbine set to be operated by the AC-Chopper device to the installed capacity of all double-fed wind turbine sets;

[0060] The second regulating module 203 is used for performing a second regulation on the power frequency temporary overvoltage according to the action voltage value of the AC-Chopper device in the doubly-fed wind turbine set of the proportion limit value in response to the comparison result that the transient voltage rise at the machine end of any doubly-fed wind turbine set is greater than the voltage rise limit value when the first regulation is performed until the proportion is equal to the self-defined proportion limit value, wherein the action voltage value is the machine end voltage value that triggers the action of the AC-Chopper device in the doubly-fed wind turbine set;

[0061] The third regulating module 204 is used to respond to the comparison result that the transient voltage rise at the machine end of any double-fed wind turbine group is greater than the voltage rise limit value when the second adjustment is performed to the action voltage value is not less than the customized action voltage lower limit value, and perform a third regulation on the power frequency temporary overvoltage according to the action delay time value of the AC-Chopper device in the double-fed wind turbine group of the proportional limit at the action voltage lower limit value.

[0062] Preferably, the first adjustment module performs a first adjustment on the power frequency temporary overvoltage according to the ratio of the installed capacity of the doubly-fed wind turbine set to be operated by the AC-Chopper device to the installed capacity of all doubly-fed wind turbine sets, wherein the first adjustment includes:

[0063] Step 2-1, according to the customized initial value P0 and step length P S Calculate the proportion P of the installed capacity of the doubly-fed wind turbine generator set that the AC-Chopper device is supposed to operate in the i-th adjustment to the installed capacity of all doubly-fed wind turbine generator sets i , and its calculation formula is:

[0064] P i =P0+(i-1)×P S

[0065] Where i is a positive integer, P0 and P S All are positive numbers less than 1;

[0066] Step 2-2, when P i <P max When the ratio P i After the AC-Chopper device that meets the initial action conditions in the AC-Chopper device of the doubly-fed wind turbine sets is actuated, the transient voltage rise at the machine end of each doubly-fed wind turbine set is obtained. Otherwise, determine the proportion P max The AC-Chopper device in the double-fed wind turbine generator system enters the second regulation, and the first regulation ends, wherein the initial action condition is that the action voltage value of the AC-Chopper device is not less than the user-defined action voltage initial value, and the action delay time value is equal to the user-defined action delay time initial value, P max is a custom scale limit;

[0067] Step 2-3: When the transient voltage rise at the terminal of any doubly-fed wind turbine generator meets the following conditions: , let i=i+1, and return to step 2-1, otherwise, the first adjustment ends, where ΔU max It is a user-defined voltage rise limit.

[0068] Preferably, the second regulating module performs a second regulation on the temporary power frequency overvoltage according to the action voltage value of the AC-Chopper device in the double-fed wind turbine set of the proportional limit value, wherein the second regulation includes:

[0069] Step 3-1: According to the customized action voltage initial value U0 and voltage step length U S Calculate the action voltage value U of the AC-Chopper device in the double-fed wind turbine set with the ratio limit at the jth adjustment j , and its calculation formula is:

[0070] U j =U0-j×U S

[0071] Where j is a positive integer, u0>u S ,u S is a positive number less than 1;

[0072] Step 3-2, when U j ≥U min When the voltage at the terminal of the doubly-fed wind turbine generator set is no less than U j After the AC-Chopper device of the doubly-fed wind turbine is activated, the transient voltage rise at the machine end of each doubly-fed wind turbine is obtained. Otherwise, the second adjustment ends, where U min It is the user-defined lower limit of the action voltage;

[0073] Step 3-3, when the transient voltage at the terminal of any doubly-fed wind turbine generator set meets When , set j=j+1 and return to step 3-1; otherwise, the second adjustment ends.

[0074] Preferably, the third adjustment module performs a third adjustment on the power frequency temporary overvoltage according to the action delay time value of the AC-Chopper device in action, wherein the third adjustment includes:

[0075] Step 4-1, according to the customized action delay time initial value T0 and time step T S Calculate the action delay time value T of the AC-Chopper device in the double-fed wind turbine generator set with the proportional limit value during the kth adjustment, so that the action voltage value is not less than the user-defined action voltage lower limit value. k , and its calculation formula is:

[0076] T k =T0-k×T S

[0077] Where k is a positive integer, T0>T S , T S is a positive number;

[0078] Step 4-2, when T k >0, in the double-fed wind turbine generator set with the ratio limit, the action voltage value is not less than the user-defined action voltage lower limit value, and the action delay time is T k After the AC-Chopper device is activated, the transient voltage rise at the machine end of each doubly fed wind turbine is obtained. Otherwise, the third adjustment ends;

[0079] Step 4-3, when the transient voltage at the terminal of any doubly-fed wind turbine generator set meets When k=k+1, return to step 4-1; otherwise, the third adjustment ends.

[0080] The device for reducing temporary overvoltage at the power frequency of the doubly-fed wind turbine set described in this preferred embodiment reduces the temporary overvoltage at the power frequency of the doubly-fed wind turbine set by gradually putting into use doubly-fed wind turbine sets equipped with AC-Chopper devices with an increasing proportion of installed capacity, and orderly adjusting the action voltage and delay time that triggers the AC-Chopper when a power grid fails. The steps are the same as the steps of the method for reducing temporary overvoltage at the power frequency of the doubly-fed wind turbine set, and the technical effects achieved are also the same, which will not be repeated here.

[0081] Exemplary Electronic Devices

[0082] Figure 3The electronic device according to the preferred embodiment of the present invention is a schematic diagram of the structure of the electronic device. The electronic device can be any one or both of the first device and the second device, or a stand-alone device independent of them, and the stand-alone device can communicate with the first device and the second device to receive the collected input signal from them. Figure 3 FIG. 1 is a block diagram of an electronic device according to an embodiment of the present disclosure. Figure 3 As shown, the electronic device includes one or more processors 301 and a memory 302 .

[0083] The processor 301 may be a central processing unit (CPU) or other forms of processing units having data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions.

[0084] The memory 302 may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory (cache), etc. The non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor 301 may run the program instructions to implement the energy consumption anomaly diagnosis method based on the enterprise energy consumption space of each disclosed embodiment described above and / or other desired functions. In one example, the electronic device may also include: an input device 303 and an output device 304, which are interconnected via a bus system and / or other forms of connection mechanisms (not shown).

[0085] In addition, the input device 303 may also include, for example, a keyboard, a mouse, and the like.

[0086] The output device 304 can output various information to the outside, and can include, for example, a display, a speaker, a printer, a communication network and a remote output device connected thereto.

[0087] Of course, to simplify, Figure 3 Only some of the components related to the present disclosure in the electronic device are shown, and components such as a bus, an input / output interface, etc. are omitted. In addition, according to specific application situations, the electronic device may further include any other appropriate components.

[0088] Exemplary computer program products and computer-readable storage media

[0089] In addition to the above-mentioned methods and devices, an embodiment of the present disclosure may also be a computer program product, which includes computer program instructions, which, when executed by a processor, enable the processor to execute the steps of the method for reducing temporary overvoltage at the power frequency of a doubly-fed wind turbine generator set according to various embodiments of the present disclosure described in the above-mentioned "Exemplary Method" section of this specification.

[0090] The computer program product may be written in any combination of one or more programming languages ​​to write program code for performing the operations of the disclosed embodiments, including object-oriented programming languages ​​such as Java, C++, etc., and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a separate software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0091] In addition, an embodiment of the present disclosure may also be a computer-readable storage medium having computer program instructions stored thereon, and when the computer program instructions are executed by a processor, the processor executes the steps of the method for reducing temporary overvoltage at the power frequency of a doubly-fed wind turbine generator set according to various embodiments of the present disclosure described in the above “Exemplary Method” section of this specification.

[0092] The computer readable storage medium can adopt any combination of one or more readable media. The readable medium can be a readable signal medium or a readable storage medium. The readable storage medium can include, for example, but is not limited to, a system, device or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination of the above. More specific examples (non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0093] The basic principles of the present disclosure are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present disclosure are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present disclosure. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, and are not limitations. The above details do not limit the present disclosure to the necessity of adopting the above specific details to be implemented.

[0094] Each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the system embodiment, since it basically corresponds to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0095] The block diagrams of the devices, apparatuses, equipment, and systems involved in this disclosure are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagrams. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including," "comprising," "having," and the like are open words, referring to "including but not limited to," and can be used interchangeably therewith. The words "or" and "and" used herein refer to the words "and / or," and can be used interchangeably therewith, unless the context clearly indicates otherwise. The word "such as" used herein refers to the phrase "such as but not limited to," and can be used interchangeably therewith.

[0096] The apparatus and method of the present disclosure may be implemented in many ways. For example, the apparatus and method of the present disclosure may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above order of steps for the method is for illustration only, and the steps of the method of the present disclosure are not limited to the order specifically described above, unless otherwise specifically stated. In addition, in some embodiments, the present disclosure may also be implemented as a program recorded in a recording medium, which includes machine-readable instructions for implementing the method according to the present disclosure. Therefore, the present disclosure also covers a recording medium storing a program for executing the method according to the present disclosure.

[0097] It should also be noted that in the apparatus, equipment and method of the present disclosure, each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent schemes of the present disclosure. The above description of the disclosed aspects is provided to enable any technician in the field to make or use the present disclosure. Various modifications to these aspects are very obvious to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of the present disclosure. Therefore, the present disclosure is not intended to be limited to the aspects shown here, but to the widest scope consistent with the principles and novel features disclosed herein.

[0098] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present disclosure to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A method for reducing temporary overvoltage of power frequency of a doubly-fed wind turbine generator set, characterized in that: The method comprises: When a fault occurs in the power grid, the transient voltage rise at the machine end of each doubly-fed wind turbine after the fault is obtained according to a custom sampling interval, wherein at least one converter inside the doubly-fed wind turbine is connected to an AC-Chopper device at the DC bus; In response to a comparison result that the transient voltage rise at the machine end of any double-fed wind turbine set at the start of a fault is greater than a user-defined voltage rise limit value, a first adjustment is made to the power frequency temporary overvoltage according to the proportion of the installed capacity of the double-fed wind turbine set to be operated by the AC-Chopper device to the installed capacity of all double-fed wind turbine sets; In response to the comparison result that the transient voltage rise at the machine end of any doubly-fed wind turbine set is greater than the voltage rise limit value when the first adjustment is performed until the ratio is equal to the user-defined ratio limit value, a second adjustment is performed on the power frequency temporary overvoltage according to the action voltage value of the AC-Chopper device in the doubly-fed wind turbine set of the ratio limit value, wherein the action voltage value is the machine end voltage value that triggers the action of the AC-Chopper device in the doubly-fed wind turbine set; In response to the comparison result that the transient voltage rise at the machine end of any doubly-fed wind turbine group is greater than the voltage rise limit value when the second adjustment is performed to the action voltage value not less than the customized action voltage lower limit value, a third adjustment is performed on the power frequency temporary overvoltage according to the action delay time value of the AC-Chopper device in the doubly-fed wind turbine group with the proportional limit value at the action voltage lower limit value.

2. The method according to claim 1, characterized in that The first adjustment of the power frequency temporary overvoltage is performed according to the ratio of the installed capacity of the doubly-fed wind turbine set to be operated by the AC-Chopper device to the installed capacity of all doubly-fed wind turbine sets, wherein the first adjustment includes: Step 2-1, according to the customized initial value P0 and step length P S Calculate the proportion P of the installed capacity of the doubly-fed wind turbine generator set that the AC-Chopper device is supposed to operate in the i-th adjustment to the installed capacity of all doubly-fed wind turbine generator sets i , and its calculation formula is: Q i =P0+(i-1)×P S Where i is a positive integer, P0 and P S All are positive numbers less than 1; Step 2-2, when P i <P max When the ratio P i After the AC-Chopper device that meets the initial action conditions in the AC-Chopper device of the doubly-fed wind turbine sets is actuated, the transient voltage rise at the machine end of each doubly-fed wind turbine set is obtained. Otherwise, determine the proportion P max The AC-Chopper device in the double-fed wind turbine generator system enters the second regulation, and the first regulation ends, wherein the initial action condition is that the action voltage value of the AC-Chopper device is not less than the user-defined action voltage initial value, and the action delay time value is equal to the user-defined action delay time initial value, P max is a custom scale limit; Step 2-3: When the transient voltage rise at the terminal of any doubly-fed wind turbine generator meets the following conditions: , let i=i+1, and return to step 2-1, otherwise, the first adjustment ends, where ΔU max It is a user-defined voltage rise limit.

3. The method according to claim 1, characterized in that The second adjustment is performed on the power frequency temporary overvoltage according to the action voltage value of the AC-Chopper device in the doubly-fed wind turbine set of the proportional limit value, wherein the second adjustment includes: Step 3-1: According to the customized action voltage initial value U0 and voltage step length U S Calculate the action voltage value U of the AC-Chopper device in the double-fed wind turbine set with the ratio limit at the jth adjustment j , and its calculation formula is: U j =U0-j×U S Where j is a positive integer, u0>u S ,u S is a positive number less than 1; Step 3-2, when U j ≥U min When the voltage at the terminal of the doubly-fed wind turbine generator set is no less than U j After the AC-Chopper device of the doubly-fed wind turbine is activated, the transient voltage rise at the machine end of each doubly-fed wind turbine is obtained. Otherwise, the second adjustment ends, where U min It is the user-defined lower limit of the action voltage; Step 3-3, when the transient voltage at the terminal of any doubly-fed wind turbine generator set meets When j=j+1, return to step 3-1; otherwise, the second adjustment ends.

4. The method according to claim 1, characterized in that The third adjustment is performed on the power frequency temporary overvoltage according to the action delay time value of the AC-Chopper device in action, wherein the third adjustment includes: Step 4-1, according to the customized action delay time initial value T0 and time step T S Calculate the action delay time value T of the AC-Chopper device in the double-fed wind turbine generator set with the proportional limit value during the kth adjustment, so that the action voltage value is not less than the user-defined action voltage lower limit value. k , and its calculation formula is: T k =T0-k×T S Where k is a positive integer, T0>T S , T S is a positive number; Step 4-2, when T k >0, in the double-fed wind turbine generator set with the said proportional limit, the action voltage value is not less than the user-defined action voltage lower limit value, and the action delay time is T k After the AC-Chopper device is activated, the transient voltage rise at the machine end of each doubly fed wind turbine is obtained. Otherwise, the third adjustment ends; Step 4-3, when the transient voltage at the terminal of any doubly-fed wind turbine generator set meets When k=k+1, return to step 4-1; otherwise, the third adjustment ends.

5. A device for reducing temporary overvoltage of power frequency of a doubly-fed wind turbine generator set, characterized in that: The device comprises: A data acquisition module is used to acquire the transient voltage rise at the machine end of each doubly-fed wind turbine after the fault occurs in the power grid according to a custom sampling interval, wherein at least one converter inside the doubly-fed wind turbine is connected to an AC-Chopper device at the DC bus; A first regulating module, configured to, in response to a comparison result that the transient voltage rise at the machine end of any double-fed wind turbine set at the start of a fault is greater than a user-defined voltage rise limit value, perform a first regulation on the power frequency temporary overvoltage according to the proportion of the installed capacity of the double-fed wind turbine set to be operated by the AC-Chopper device to the installed capacity of all double-fed wind turbine sets; A second regulating module is used for performing a second regulation on the power frequency temporary overvoltage according to the action voltage value of the AC-Chopper device in the doubly-fed wind turbine set of the proportion limit value in response to the comparison result that the transient voltage rise at the machine end of any doubly-fed wind turbine set is greater than the voltage rise limit value when the first regulation is performed until the proportion is equal to the self-defined proportion limit value, wherein the action voltage value is the machine end voltage value that triggers the action of the AC-Chopper device in the doubly-fed wind turbine set; The third regulation module is used to respond to the comparison result that the transient voltage rise at the machine end of any double-fed wind turbine group is greater than the voltage rise limit value when the second adjustment is performed to the action voltage value not less than the customized action voltage lower limit value, and perform a third regulation on the power frequency temporary overvoltage according to the action delay time value of the AC-Chopper device in the double-fed wind turbine group of the proportional limit value at the action voltage lower limit value.

6. The device according to claim 5, characterized in that The first adjustment module performs a first adjustment on the power frequency temporary overvoltage according to the proportion of the installed capacity of the double-fed wind turbine set to be operated by the AC-Chopper device to the installed capacity of all double-fed wind turbine sets, wherein the first adjustment includes: Step 2-1, according to the customized initial value P0 and step length P S Calculate the proportion P of the installed capacity of the doubly-fed wind turbine generator set that the AC-Chopper device is supposed to operate in the i-th adjustment to the installed capacity of all doubly-fed wind turbine generator sets i , and its calculation formula is: Q i =P0+(i-1)×P S Where i is a positive integer, P0 and P S All are positive numbers less than 1; Step 2-2, when P i <P max When the ratio P i After the AC-Chopper device that meets the initial action conditions in the AC-Chopper device of the doubly-fed wind turbine sets is actuated, the transient voltage rise at the machine end of each doubly-fed wind turbine set is obtained. Otherwise, determine the proportion P max The AC-Chopper device in the double-fed wind turbine generator system enters the second regulation, and the first regulation ends, wherein the initial action condition is that the action voltage value of the AC-Chopper device is not less than the user-defined action voltage initial value, and the action delay time value is equal to the user-defined action delay time initial value, P max is a custom scale limit; Step 2-3: When the transient voltage rise at the terminal of any doubly-fed wind turbine generator meets the following conditions: , let i=i+1, and return to step 2-1, otherwise, the first adjustment ends, where ΔU max It is a user-defined voltage rise limit.

7. The device according to claim 5, characterized in that The second regulating module performs a second regulation on the power frequency temporary overvoltage according to the action voltage value of the AC-Chopper device in the double-fed wind turbine set of the proportional limit value, wherein the second regulation includes: Step 3-1: According to the customized action voltage initial value U0 and voltage step length U S Calculate the action voltage value U of the AC-Chopper device in the double-fed wind turbine set with the ratio limit at the jth adjustment j , and its calculation formula is: U j =U0-j×U S Where j is a positive integer, U0>U S , U S is a positive number less than 1; Step 3-2, when U j ≥U min When the voltage at the terminal of the doubly-fed wind turbine generator set is no less than U j After the AC-Chopper device of the doubly-fed wind turbine is activated, the transient voltage rise at the machine end of each doubly-fed wind turbine is obtained. Otherwise, the second adjustment ends, where U min It is the user-defined lower limit of the action voltage; Step 3-3, when the transient voltage at the terminal of any doubly-fed wind turbine generator set meets When j=j+1, return to step 3-1; otherwise, the second adjustment ends.

8. The device according to claim 5, characterized in that The third adjustment module performs a third adjustment on the power frequency temporary overvoltage according to the action delay time value of the AC-Chopper device in action, wherein the third adjustment includes: Step 4-1, according to the customized action delay time initial value T0 and time step T S Calculate the action delay time value T of the AC-Chopper device in the double-fed wind turbine generator set with the proportional limit value during the kth adjustment, so that the action voltage value is not less than the user-defined action voltage lower limit value. k , and its calculation formula is: T k =T0-k×T S Where k is a positive integer, T0>T S , T S is a positive number; Step 4-2, when T k >0, in the double-fed wind turbine generator set with the said proportional limit, the action voltage value is not less than the user-defined action voltage lower limit value, and the action delay time is T k After the AC-Chopper device is activated, the transient voltage rise at the machine end of each doubly fed wind turbine is obtained. Otherwise, the third adjustment ends; Step 4-3, when the transient voltage at the terminal of any doubly-fed wind turbine generator set meets When k=k+1, return to step 4-1; otherwise, the third adjustment ends.

9. A computer-readable storage medium, characterized in that: The storage medium stores a computer program, and the computer program is used to execute the method according to any one of claims 1 to 4 above.

10. An electronic device, characterized in that: The electronic device comprises: processor; a memory for storing instructions executable by the processor; The processor is used to read the executable instructions from the memory and execute the instructions to implement the method described in any one of claims 1 to 4 above.

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