Voltage amplitude calculation method and device based on high and low voltage ride-through fault strategy

Abstract

The invention provides a voltage amplitude calculation method and device based on a high-low voltage ride-through fault strategy, and relates to the technical field of fault testing. The method comprises the following steps: acquiring an equivalent voltage source and an equivalent resistance-inductance system, and calculating a resistance-inductance angle according to the equivalent resistance-inductance system and an angular frequency; according to the equivalent voltage source, the reactive current correlation intermediate value, the resistance-inductance angle and the reactive support coefficient in the high-low voltage ride-through period, calculating to obtain a to-be-judged voltage amplitude under a high-low voltage ride-through fault strategy; if it is determined that the to-be-judged voltage amplitude is larger than zero, the voltage ride-through state is determined according to the numerical value interval where the resistance-inductance angle is located, and according to the voltage ride-through state, the to-be-judged voltage amplitude and the high-low voltage fault judgment threshold value, the target voltage amplitude is obtained through calculation. The device executes the method. According to the method and the device provided by the embodiment of the invention, grid-connected point voltage amplitude calculation under a high-low voltage ride-through fault strategy can be accurately realized.

Description

Technical Field

[0001] The present invention relates to the technical field of fault testing, and in particular to a voltage amplitude calculation method and device based on a high and low voltage ride-through fault strategy. Background Art

[0002] The new energy reactive power compensation device is an important voltage support device for new energy stations. During the grid-connected operation, the new energy reactive power compensation device needs to have the ability to ride through high and low voltage faults. Under the high and low voltage fault ride-through strategy of the new energy reactive power compensation device, the new energy reactive power compensation device outputs the corresponding reactive current according to the system voltage drop to support the grid connection point voltage. Under the current high and low voltage fault ride-through strategy of the new energy reactive power compensation device, the grid connection point voltage amplitude changes with the reactive current output by the new energy equipment. Although it provides voltage support capability, it cannot accurately reflect the change in the grid connection point voltage amplitude. Summary of the invention

[0003] In view of the problems in the prior art, an embodiment of the present invention provides a method and device for calculating voltage amplitude based on a high and low voltage ride-through fault strategy, which can at least partially solve the problems in the prior art.

[0004] On the one hand, the present invention proposes a voltage amplitude calculation method based on a high and low voltage ride-through fault strategy, comprising:

[0005] Equivalently merging the system equivalent branch and the high and low voltage fault branches to obtain an equivalent voltage source and an equivalent resistance-inductance system, and calculating the resistance-inductance angle according to the equivalent resistance-inductance system and the angular frequency;

[0006] The voltage amplitude to be determined under the high and low voltage ride through fault strategy is calculated according to the equivalent voltage source, the intermediate value related to the reactive current, the resistance-inductance angle and the reactive support coefficient during the high and low voltage ride through period;

[0007] If it is determined that the voltage amplitude to be determined is greater than zero, the voltage ride-through state is determined according to the numerical interval of the resistance-inductance angle, and the target voltage amplitude is calculated according to the voltage ride-through state, the voltage amplitude to be determined and the high and low voltage fault judgment thresholds.

[0008] The voltage amplitude to be determined under the high and low voltage ride through fault strategy is calculated based on the equivalent voltage source, the intermediate value related to the reactive current, the resistance-inductance angle and the reactive support coefficient during the high and low voltage ride through, including:

[0009] Calculate the first voltage phase angle and the second voltage phase angle of the grid connection point voltage leading system according to the equivalent voltage source, the reactive current related intermediate value, the resistance-inductance angle and the reactive support coefficient during the high and low voltage ride-through period;

[0010] Calculate a first voltage amplitude to be determined according to the reactive current related intermediate value, the resistance-inductance angle, the first voltage phase angle and the reactive support coefficient during the high and low voltage ride-through period;

[0011] The second voltage amplitude to be determined is calculated based on the reactive current related intermediate value, the resistance-inductance angle, the second voltage phase angle and the reactive support coefficient during the high and low voltage ride-through period.

[0012] The first voltage amplitude to be determined is calculated based on the reactive current related intermediate value, the resistance-inductance angle, the first voltage phase angle and the reactive support coefficient during the high and low voltage ride-through period, including:

[0013] The first voltage amplitude to be determined U is calculated according to the following formula d1 :

[0014]

[0015] Among them, m is the intermediate value related to the reactive current, a is the resistance-inductance angle, q1 is the first voltage phase angle, and k is the reactive support coefficient during the high and low voltage ride-through period.

[0016] The step of calculating the second voltage amplitude to be determined according to the reactive current related intermediate value, the resistance-inductance angle, the second voltage phase angle and the reactive support coefficient during the high and low voltage ride-through period includes:

[0017] The second voltage amplitude to be determined U is calculated according to the following formula d2 :

[0018]

[0019] Among them, m is the intermediate value related to the reactive current, a is the resistance-inductance angle, q2 is the second voltage phase angle, and k is the reactive support coefficient during the high and low voltage ride-through period.

[0020] The step of calculating the target voltage amplitude according to the voltage ride-through state, the voltage amplitude to be determined and the high and low voltage fault judgment thresholds includes:

[0021] If it is determined that the voltage ride-through state is a high voltage ride-through state, the larger of the first voltage amplitude to be determined and the second voltage amplitude to be determined that are greater than the high and low voltage fault judgment thresholds is used as the target voltage amplitude.

[0022] The step of calculating the target voltage amplitude according to the voltage ride-through state, the voltage amplitude to be determined and the high and low voltage fault judgment thresholds includes:

[0023] If it is determined that the voltage ride-through state is a low voltage ride-through state, the smaller of the first voltage amplitude to be determined and the second voltage amplitude to be determined that are smaller than the high and low voltage fault judgment thresholds is used as the target voltage amplitude.

[0024] Wherein, the voltage amplitude calculation method based on the high and low voltage ride-through fault strategy also includes:

[0025] The voltage amplitude to be determined that is less than or equal to zero is directly regarded as an invalid target voltage amplitude.

[0026] On the one hand, the present invention proposes a voltage amplitude calculation device based on a high and low voltage ride-through fault strategy, comprising:

[0027] A first calculation unit is used to perform equivalent merging of the system equivalent branch and the high and low voltage fault branches to obtain an equivalent voltage source and an equivalent resistance-inductance system, and calculate the resistance-inductance angle according to the equivalent resistance-inductance system and the angular frequency;

[0028] A second calculation unit is used to calculate the voltage amplitude to be determined under the high and low voltage ride through fault strategy according to the equivalent voltage source, the intermediate value related to the reactive current, the resistance-inductance angle and the reactive support coefficient during the high and low voltage ride through period;

[0029] The third calculation unit is used to determine the voltage crossing state according to the numerical interval of the resistance-inductance angle if it is determined that the voltage amplitude to be determined is greater than zero, and calculate the target voltage amplitude according to the voltage crossing state, the voltage amplitude to be determined and the high and low voltage fault judgment thresholds.

[0030] In another aspect, an embodiment of the present invention provides an electronic device, including: a processor, a memory, and a bus, wherein:

[0031] The processor and the memory communicate with each other via the bus;

[0032] The memory stores program instructions that can be executed by the processor, and the processor calls the program instructions to execute the following method:

[0033] Equivalently merging the system equivalent branch and the high and low voltage fault branches to obtain an equivalent voltage source and an equivalent resistance-inductance system, and calculating the resistance-inductance angle according to the equivalent resistance-inductance system and the angular frequency;

[0034] The voltage amplitude to be determined under the high and low voltage ride through fault strategy is calculated according to the equivalent voltage source, the intermediate value related to the reactive current, the resistance-inductance angle and the reactive support coefficient during the high and low voltage ride through period;

[0035] If it is determined that the voltage amplitude to be determined is greater than zero, the voltage ride-through state is determined according to the numerical interval of the resistance-inductance angle, and the target voltage amplitude is calculated according to the voltage ride-through state, the voltage amplitude to be determined and the high and low voltage fault judgment thresholds.

[0036] An embodiment of the present invention provides a non-transitory computer-readable storage medium, including:

[0037] The non-transitory computer-readable storage medium stores computer instructions, which cause the computer to execute the following method:

[0038] Equivalently merging the system equivalent branch and the high and low voltage fault branches to obtain an equivalent voltage source and an equivalent resistance-inductance system, and calculating the resistance-inductance angle according to the equivalent resistance-inductance system and the angular frequency;

[0039] The voltage amplitude to be determined under the high and low voltage ride through fault strategy is calculated according to the equivalent voltage source, the intermediate value related to the reactive current, the resistance-inductance angle and the reactive support coefficient during the high and low voltage ride through period;

[0040] If it is determined that the voltage amplitude to be determined is greater than zero, the voltage ride-through state is determined according to the numerical interval of the resistance-inductance angle, and the target voltage amplitude is calculated according to the voltage ride-through state, the voltage amplitude to be determined and the high and low voltage fault judgment thresholds.

[0041] The voltage amplitude calculation method and device based on the high and low voltage ride-through fault strategy provided by the embodiment of the present invention perform equivalent merging of system equivalent branches and high and low voltage fault branches to obtain an equivalent voltage source and an equivalent resistance-inductance system, and calculate the resistance-inductance angle according to the equivalent resistance-inductance system and the angular frequency; calculate the voltage amplitude to be determined under the high and low voltage ride-through fault strategy according to the equivalent voltage source, the intermediate value related to reactive current, the resistance-inductance angle and the reactive support coefficient during the high and low voltage ride-through period; if it is determined that the voltage amplitude to be determined is greater than zero, determine the voltage ride-through state according to the numerical interval where the resistance-inductance angle is located, and calculate the target voltage amplitude according to the voltage ride-through state, the voltage amplitude to be determined and the high and low voltage fault judgment threshold, so as to accurately realize the voltage amplitude calculation of the grid connection point under the high and low voltage ride-through fault strategy. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0043] Figure 1 It is a flow chart of a voltage amplitude calculation method based on a high and low voltage ride-through fault strategy provided by an embodiment of the present invention.

[0044] Figure 2 It is a system equivalent circuit diagram of a new energy reactive power compensation device provided by an embodiment of the present invention under a high voltage ride-through fault strategy.

[0045] Figure 3 It is a system equivalent circuit diagram of a new energy reactive power compensation device provided by an embodiment of the present invention under a low voltage ride-through fault strategy.

[0046] Figure 4 It is a flow chart of a voltage amplitude calculation method based on a high and low voltage ride-through fault strategy provided by another embodiment of the present invention.

[0047] Figure 5 It is a structural schematic diagram of a voltage amplitude calculation device based on a high and low voltage ride-through fault strategy provided by an embodiment of the present invention.

[0048] Figure 6 A schematic diagram of the physical structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention. It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other arbitrarily.

[0050] Figure 1 is a flow chart of a voltage amplitude calculation method based on a high and low voltage ride-through fault strategy provided by an embodiment of the present invention, such as Figure 1 As shown, the voltage amplitude calculation method based on the high and low voltage ride-through fault strategy provided by the embodiment of the present invention includes:

[0051] Step S1: equivalently merging the system equivalent branch and the high and low voltage fault branches to obtain an equivalent voltage source and an equivalent resistance-inductance system, and calculating the resistance-inductance angle according to the equivalent resistance-inductance system and the angular frequency.

[0052] Step S2: Calculate the voltage amplitude to be determined under the high and low voltage ride through fault strategy according to the equivalent voltage source, the intermediate value related to the reactive current, the resistance-inductance angle and the reactive support coefficient during the high and low voltage ride through.

[0053] Step S3: If it is determined that the voltage amplitude to be determined is greater than zero, the voltage crossing state is determined according to the numerical interval of the resistance-inductance angle, and the target voltage amplitude is calculated according to the voltage crossing state, the voltage amplitude to be determined and the high and low voltage fault judgment thresholds.

[0054] In the above step S1, the device performs equivalent merging of the system equivalent branch and the high and low voltage fault branch to obtain an equivalent voltage source and an equivalent resistance-inductance system, and obtains the resistance-inductance angle according to the equivalent resistance-inductance system and the angular frequency. The device may be a computer device that executes the method. It should be noted that the acquisition and analysis of data involved in the embodiments of the present invention are authorized by the user. Figure 2 and Figure 3 As shown, it is the system equivalent circuit of the new energy reactive power compensation device under the high and low voltage ride-through fault strategy.

[0055] The system equivalent voltage can be obtained through large power grid simulation, and the system voltage amplitude and phase remain stable. The system equivalent voltage can be expressed as

[0056] Among them, U s is the voltage amplitude, w′t is the phase, a us is the system equivalent voltage phase angle, which can be set to 0, and w is the angular frequency, which is 314.

[0057] The system equivalent impedance is the external equivalent impedance parameter of the grid connection point of the new energy equipment. The system equivalent impedance can be expressed as

[0058] Among them, the system short-circuit current a is is the system equivalent current phase angle, I s is the current amplitude.

[0059] Impedance amplitude |Z|=sqrt(R s ′R s +w′w′L s 'L s ).

[0060] Assuming the system impedance ratio You can get R s =|Z|′sqrt(1+K 2 ), L s =|Z|′sqrt(1+K 2 )′K / w.

[0061] Assume that the short-circuit resistance of the high voltage ride-through fault test is set to R x , the capacitance parameter is C x , the no-load equivalent impedance of the new energy equipment branch is R ￥It is generally believed that R ￥ is a value close to infinity. In the actual test process, there is a no-load weak current situation, so it is considered that R ￥ It is a very large value.

[0062] The height increase depth of high voltage ride-through is k￠, and during the high voltage ride-through of new energy equipment units, the values ​​are 1.2, 1.25, and 1.3 respectively.

[0063] The short circuit resistance is R x , the capacitance parameter is C x , and the system impedance R s +jwL s It is related to the value of k￠ and satisfies the following constraints:

[0064]

[0065] Through the above constraints, under different high voltage ride-through drop requirements, by setting the short-circuit resistance R x , we can get the corresponding capacitance C x , and then the high voltage ride through fault parameters can be determined.

[0066] Low voltage ride-through adopts the form of resistance-inductance voltage division, which requires the short-circuit branch to be converted into a resistor R x and inductor L x Series connection form, similar principles will not be repeated.

[0067] According to the Thevenin equivalent principle, the system equivalent branch and the high and low voltage fault branches can be equivalently combined to obtain the equivalent voltage source And the equivalent resistance-inductance system R s ￠+jwL s ￠, where During low voltage ride through fault Z x =R x +jwL x , high voltage ride through fault period Z x =R x +1 / (jwC x ), a1 is the phase angle of the equivalent voltage source.

[0068] The resistance-sensitivity angle is calculated according to the equivalent resistance-sensitivity system and the angular frequency, including:

[0069] The resistance-sensitivity angle a is calculated according to the following formula:

[0070]

[0071] Among them, R s ￠ is the resistance of the equivalent resistance-inductance system, L s ￠ is the inductance of the equivalent resistance-inductance system.

[0072] In the above step S2, the device calculates the voltage amplitude to be determined under the high and low voltage ride-through fault strategy according to the equivalent voltage source, the intermediate value related to reactive current, the resistance-sensitivity angle and the reactive support coefficient during high and low voltage ride-through. The intermediate value m related to reactive current is calculated according to the following formula:

[0073] m=I q0 +k′U set

[0074] Among them, I q0 is the initial value of reactive current emitted by the reactive compensation device before the high and low voltage fault, k is the reactive support coefficient during the high and low voltage ride-through period, U set is the high and low voltage fault judgment threshold, k and U set This can be found by referring to the relevant instructions of the reactive power compensation device.

[0075] Reactive current I of reactive compensation device during high and low voltage fault ride-through q The target value should satisfy the following relationship:

[0076] I q =I q0 +k′(U d -U set )

[0077] Among them, U d It is the voltage value of the grid connection point after the high and low voltage ride-through fault.

[0078] The voltage amplitude to be determined under the high and low voltage ride through fault strategy is calculated based on the equivalent voltage source, the intermediate value related to the reactive current, the resistance-inductance angle and the reactive support coefficient during the high and low voltage ride through, including:

[0079] Calculate the first voltage phase angle and the second voltage phase angle of the grid connection point voltage leading system according to the equivalent voltage source, the reactive current related intermediate value, the resistance-inductance angle and the reactive support coefficient during the high and low voltage ride-through period;

[0080] The first voltage phase angle q1 is calculated according to the following formula:

[0081]

[0082] The second voltage phase angle q2 is calculated according to the following formula:

[0083]

[0084] Among them, a, b and c are the coefficients to be solved, which are expressed by the following expressions:

[0085]

[0086] Calculate a first voltage amplitude to be determined according to the reactive current related intermediate value, the resistance-inductance angle, the first voltage phase angle and the reactive support coefficient during the high and low voltage ride-through period;

[0087] The first voltage amplitude to be determined U is calculated according to the following formula d1 :

[0088]

[0089] The second voltage amplitude to be determined is calculated based on the reactive current related intermediate value, the resistance-inductance angle, the second voltage phase angle and the reactive support coefficient during the high and low voltage ride-through period.

[0090] The second voltage amplitude to be determined U is calculated according to the following formula d2 :

[0091]

[0092] Assume that the reactive power generated by the reactive compensation device under the high voltage ride-through strategy is Q. When Q>0, it is determined that the system generates capacitive reactive power. When Q<0, it is determined that the system generates inductive reactive power. q0 It is the effective value of the current calculated under the reactive power instruction Q before the fault.

[0093] The derivation process for calculating the grid connection point voltage is described as follows:

[0094] Assume that the transient voltage of the reactive power compensation device at the grid connection point during high and low voltage faults is Among them, U d is the grid connection point voltage value after the high and low voltage ride-through fault, and q is the phase angle of the grid connection point voltage leading the system voltage.

[0095] Get the vector relationship equation:

[0096]

[0097] Among them, U L =-(I q0 -k′U set )′w′L s ￠,U R =(I q0 -k′U set )′R s ￠, The amplitude is U d , a vector with a phase of 2 times q, The amplitude is U s ￠, a vector with phase q.

[0098] Further simplification gives U d The relationship equation with q is:

[0099]

[0100] After the actual high and low voltage ride-through fault parameters are set, it is generally believed that the q value is not large, and the following two equivalent constraints can be obtained:

[0101]

[0102] After further simplification, we get the following quadratic equation:

[0103] (m′cos 2 (a)-m-sin(a)′U s ￠-k′cos(a))′q 2 -

[0104] (m′sin(2′a)-k′U s ￠′sin 2 (a))′q+m′sin 2 (a)=0

[0105] The coefficients a, b and c are further obtained as follows:

[0106]

[0107] We can further solve it to get:

[0108]

[0109] In the above step S3, if the device determines that the voltage amplitude to be determined is greater than zero, it determines the voltage crossing state according to the numerical interval of the resistance-sensitivity angle, and calculates the target voltage amplitude according to the voltage crossing state, the voltage amplitude to be determined and the high and low voltage fault judgment thresholds.

[0110] The step of calculating the target voltage amplitude according to the voltage ride-through state, the voltage amplitude to be determined, and the high and low voltage fault judgment thresholds includes:

[0111] If it is determined that the voltage ride-through state is a high voltage ride-through state, the larger of the first voltage amplitude to be determined and the second voltage amplitude to be determined that are greater than the high and low voltage fault judgment thresholds is used as the target voltage amplitude.

[0112] The step of calculating the target voltage amplitude according to the voltage ride-through state, the voltage amplitude to be determined, and the high and low voltage fault judgment thresholds includes:

[0113] If it is determined that the voltage ride-through state is a low voltage ride-through state, the smaller of the first voltage amplitude to be determined and the second voltage amplitude to be determined that are smaller than the high and low voltage fault judgment thresholds is used as the target voltage amplitude.

[0114] like Figure 4 As shown, the calculated U d1 and U d2 Should be greater than 0. If U d1 and U d2 If there is a value less than or equal to 0 in U, then the value less than or equal to 0 can be considered invalid. d1 and U d2 If both are greater than 0, the decision is made based on the value of a, as follows:

[0115] when When the voltage ride-through state is determined to be a high voltage ride-through state, the first voltage amplitude to be determined and the second voltage amplitude to be determined can be compared with the high and low voltage fault judgment thresholds respectively. If one is greater than the high and low voltage fault judgment thresholds and the other is less than the high and low voltage fault judgment thresholds, the voltage amplitude to be determined that is greater than the high and low voltage fault judgment thresholds is directly used as the target voltage amplitude.

[0116] If both are greater than the high and low voltage fault judgment thresholds, the two are numerically compared again, and the larger one is used as the target voltage amplitude.

[0117] If both are less than or equal to the high and low voltage fault judgment thresholds, they are both determined as invalid target voltage amplitudes.

[0118] when When the voltage ride-through state is determined to be a low voltage ride-through state, the first voltage amplitude to be determined and the second voltage amplitude to be determined can be compared with the high and low voltage fault judgment thresholds respectively. If one is greater than the high and low voltage fault judgment thresholds and the other is less than the high and low voltage fault judgment thresholds, the voltage amplitude to be determined that is less than the high and low voltage fault judgment thresholds is directly used as the target voltage amplitude.

[0119] If both are smaller than the high and low voltage fault judgment thresholds, the two are numerically compared again, and the smaller one is used as the target voltage amplitude.

[0120] If both are greater than or equal to the high and low voltage fault judgment thresholds, they are both determined as invalid target voltage amplitudes.

[0121] The voltage amplitude calculation method based on the high and low voltage ride-through fault strategy provided in the embodiment of the present invention can calculate the grid-connected voltage amplitude of the reactive compensation device corresponding to different high and low voltage fault conditions by obtaining the external equivalent system network of the new energy equipment grid-connected point, the high and low voltage short-circuit fault parameters and the active branch of the grid-connected point through the calculation method of the present invention, thereby accurately evaluating the supporting capacity of the reactive compensation device to the grid-connected power grid during the high and low voltage fault ride-through period.

[0122] The voltage amplitude calculation method based on the high and low voltage ride-through fault strategy provided by the embodiment of the present invention performs equivalent merging of system equivalent branches and high and low voltage fault branches to obtain an equivalent voltage source and an equivalent resistance-inductance system, and calculates the resistance-inductance angle according to the equivalent resistance-inductance system and the angular frequency; the voltage amplitude to be determined under the high and low voltage ride-through fault strategy is calculated according to the equivalent voltage source, the intermediate value related to reactive current, the resistance-inductance angle and the reactive support coefficient during the high and low voltage ride-through period; if it is determined that the voltage amplitude to be determined is greater than zero, the voltage ride-through state is determined according to the numerical interval where the resistance-inductance angle is located, and the target voltage amplitude is calculated according to the voltage ride-through state, the voltage amplitude to be determined and the high and low voltage fault judgment threshold, so as to accurately realize the voltage amplitude calculation of the grid connection point under the high and low voltage ride-through fault strategy.

[0123] Further, the voltage amplitude to be determined under the high and low voltage ride through fault strategy is calculated based on the equivalent voltage source, the intermediate value related to the reactive current, the resistance-inductance angle and the reactive support coefficient during the high and low voltage ride through, including:

[0124] According to the equivalent voltage source, the reactive current related intermediate value, the resistance-inductance angle and the reactive support coefficient during the high and low voltage crossing period, the first voltage phase angle and the second voltage phase angle of the grid connection point voltage leading system are calculated; the above-mentioned embodiment can be referred to for description and will not be repeated here.

[0125] The first voltage amplitude to be determined is calculated based on the reactive current related intermediate value, the resistance-inductance angle, the first voltage phase angle and the reactive support coefficient during the high and low voltage crossing period; the description can be made with reference to the above embodiment and will not be repeated here.

[0126] The second voltage amplitude to be determined is calculated based on the reactive current related intermediate value, the resistance-inductance angle, the second voltage phase angle and the reactive support coefficient during the high and low voltage ride-through period.

[0127] Further, the first voltage amplitude to be determined is calculated according to the reactive current related intermediate value, the resistance-inductance angle, the first voltage phase angle and the reactive support coefficient during the high and low voltage ride-through, including:

[0128] The first voltage amplitude to be determined U is calculated according to the following formula d1 :

[0129]

[0130] Wherein, m is the intermediate value related to the reactive current, a is the resistance-inductance angle, q1 is the first voltage phase angle, and k is the reactive support coefficient during the high and low voltage ride-through period.

[0131] Further, the second voltage amplitude to be determined is calculated according to the reactive current related intermediate value, the resistance-inductance angle, the second voltage phase angle and the reactive support coefficient during the high and low voltage ride-through, including:

[0132] The second voltage amplitude to be determined U is calculated according to the following formula d2 :

[0133]

[0134] Wherein, m is the intermediate value related to the reactive current, a is the resistance-inductance angle, q2 is the second voltage phase angle, and k is the reactive support coefficient during the high and low voltage ride-through period. The above-mentioned embodiments can be referred to for explanation and will not be described in detail.

[0135] Further, the target voltage amplitude is calculated according to the voltage ride-through state, the voltage amplitude to be determined and the high and low voltage fault judgment thresholds, including:

[0136] If the voltage ride-through state is determined to be a high voltage ride-through state, the larger of the first voltage amplitude to be determined and the second voltage amplitude to be determined that is greater than the high and low voltage fault judgment threshold is used as the target voltage amplitude. The above embodiment can be referred to for explanation and will not be repeated.

[0137] Further, the target voltage amplitude is calculated according to the voltage ride-through state, the voltage amplitude to be determined and the high and low voltage fault judgment thresholds, including:

[0138] If the voltage ride-through state is determined to be a low voltage ride-through state, the smaller of the first voltage amplitude to be determined and the second voltage amplitude to be determined that are smaller than the high and low voltage fault judgment thresholds is used as the target voltage amplitude. The above embodiments can be referred to for explanation and will not be described in detail.

[0139] Furthermore, the voltage amplitude calculation method based on the high and low voltage ride-through fault strategy also includes:

[0140] The voltage amplitude to be determined that is less than or equal to zero is directly used as an invalid target voltage amplitude. The above description can be referred to, and no further details are given.

[0141] Figure 5 is a schematic diagram of the structure of a voltage amplitude calculation device based on a high and low voltage ride-through fault strategy provided by an embodiment of the present invention, such as Figure 5 As shown, the voltage amplitude calculation device based on the high and low voltage ride-through fault strategy provided by the embodiment of the present invention includes a first calculation unit 501, a second calculation unit 502 and a third calculation unit 503, wherein:

[0142] The first calculation unit 501 is used to perform equivalent merging of the system equivalent branches and the high and low voltage fault branches to obtain an equivalent voltage source and an equivalent resistance-inductance system, and calculate the resistance-inductance angle based on the equivalent resistance-inductance system and the angular frequency; the second calculation unit 502 is used to calculate the voltage amplitude to be determined under the high and low voltage crossing fault strategy based on the equivalent voltage source, the relevant intermediate value of the reactive current, the resistance-inductance angle and the reactive support coefficient during the high and low voltage crossing; the third calculation unit 503 is used to determine the voltage crossing state according to the numerical interval of the resistance-inductance angle if it is determined that the voltage amplitude to be determined is greater than zero, and calculate the target voltage amplitude according to the voltage crossing state, the voltage amplitude to be determined and the high and low voltage fault judgment threshold.

[0143] Specifically, the first calculation unit 501 in the device is used to perform equivalent merging of the system equivalent branches and the high and low voltage fault branches to obtain an equivalent voltage source and an equivalent resistance-inductance system, and calculate the resistance-inductance angle based on the equivalent resistance-inductance system and the angular frequency; the second calculation unit 502 is used to calculate the voltage amplitude to be determined under the high and low voltage crossing fault strategy based on the equivalent voltage source, the relevant intermediate value of the reactive current, the resistance-inductance angle and the reactive support coefficient during the high and low voltage crossing; the third calculation unit 503 is used to determine the voltage crossing state according to the numerical interval of the resistance-inductance angle if it is determined that the voltage amplitude to be determined is greater than zero, and calculate the target voltage amplitude according to the voltage crossing state, the voltage amplitude to be determined and the high and low voltage fault judgment threshold.

[0144] The voltage amplitude calculation device based on the high and low voltage ride-through fault strategy provided by the embodiment of the present invention performs equivalent merging of system equivalent branches and high and low voltage fault branches to obtain an equivalent voltage source and an equivalent resistance-inductance system, and calculates the resistance-inductance angle according to the equivalent resistance-inductance system and the angular frequency; calculates the voltage amplitude to be determined under the high and low voltage ride-through fault strategy according to the equivalent voltage source, the intermediate value related to reactive current, the resistance-inductance angle and the reactive support coefficient during the high and low voltage ride-through period; if it is determined that the voltage amplitude to be determined is greater than zero, the voltage ride-through state is determined according to the numerical interval where the resistance-inductance angle is located, and the target voltage amplitude is calculated according to the voltage ride-through state, the voltage amplitude to be determined and the high and low voltage fault judgment threshold, so as to accurately realize the voltage amplitude calculation of the grid connection point under the high and low voltage ride-through fault strategy.

[0145] The embodiment of the present invention provides an embodiment of a voltage amplitude calculation device based on a high and low voltage ride-through fault strategy, which can be specifically used to execute the processing flow of the above-mentioned method embodiments. Its functions are not repeated here, and reference can be made to the detailed description of the above-mentioned method embodiments.

[0146] Figure 6 A schematic diagram of the physical structure of an electronic device provided by an embodiment of the present invention, such as Figure 6 As shown, the electronic device includes: a processor (processor) 601, a memory (memory) 602 and a bus 603;

[0147] The processor 601 and the memory 602 communicate with each other via a bus 603;

[0148] The processor 601 is used to call the program instructions in the memory 602 to execute the methods provided by the above method embodiments, for example, including:

[0149] Equivalently merging the system equivalent branch and the high and low voltage fault branches to obtain an equivalent voltage source and an equivalent resistance-inductance system, and calculating the resistance-inductance angle according to the equivalent resistance-inductance system and the angular frequency;

[0150] The voltage amplitude to be determined under the high and low voltage ride through fault strategy is calculated according to the equivalent voltage source, the intermediate value related to the reactive current, the resistance-inductance angle and the reactive support coefficient during the high and low voltage ride through period;

[0151] If it is determined that the voltage amplitude to be determined is greater than zero, the voltage ride-through state is determined according to the numerical interval of the resistance-inductance angle, and the target voltage amplitude is calculated according to the voltage ride-through state, the voltage amplitude to be determined and the high and low voltage fault judgment thresholds.

[0152] This embodiment discloses a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium. The computer program includes program instructions. When the program instructions are executed by a computer, the computer can perform the methods provided by the above method embodiments, for example, including:

[0153] Equivalently merging the system equivalent branch and the high and low voltage fault branches to obtain an equivalent voltage source and an equivalent resistance-inductance system, and calculating the resistance-inductance angle according to the equivalent resistance-inductance system and the angular frequency;

[0154] The voltage amplitude to be determined under the high and low voltage ride through fault strategy is calculated according to the equivalent voltage source, the intermediate value related to the reactive current, the resistance-inductance angle and the reactive support coefficient during the high and low voltage ride through period;

[0155] If it is determined that the voltage amplitude to be determined is greater than zero, the voltage ride-through state is determined according to the numerical interval of the resistance-inductance angle, and the target voltage amplitude is calculated according to the voltage ride-through state, the voltage amplitude to be determined and the high and low voltage fault judgment thresholds.

[0156] This embodiment provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, wherein the computer program enables the computer to execute the methods provided by the above method embodiments, for example, including:

[0157] Equivalently merging the system equivalent branch and the high and low voltage fault branches to obtain an equivalent voltage source and an equivalent resistance-inductance system, and calculating the resistance-inductance angle according to the equivalent resistance-inductance system and the angular frequency;

[0158] The voltage amplitude to be determined under the high and low voltage ride through fault strategy is calculated according to the equivalent voltage source, the intermediate value related to the reactive current, the resistance-inductance angle and the reactive support coefficient during the high and low voltage ride through period;

[0159] If it is determined that the voltage amplitude to be determined is greater than zero, the voltage ride-through state is determined according to the numerical interval of the resistance-inductance angle, and the target voltage amplitude is calculated according to the voltage ride-through state, the voltage amplitude to be determined and the high and low voltage fault judgment thresholds.

[0160] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0161] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0162] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0163] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0164] In the description of this specification, the description with reference to the terms "one embodiment", "a specific embodiment", "some embodiments", "for example", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0165] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A voltage amplitude calculation method based on high and low voltage ride-through fault strategy, characterized in that: include: Equivalently merge the system equivalent branch and the high and low voltage fault branches to obtain an equivalent voltage source and an equivalent resistance-inductance system, and calculate the resistance-inductance angle according to the equivalent resistance-inductance system and the angular frequency; The voltage amplitude to be determined under the high and low voltage ride through fault strategy is calculated according to the equivalent voltage source, the intermediate value related to the reactive current, the resistance-inductance angle and the reactive support coefficient during the high and low voltage ride through period; If it is determined that the voltage amplitude to be determined is greater than zero, the voltage ride-through state is determined according to the numerical interval of the resistance-inductance angle, and the target voltage amplitude is calculated according to the voltage ride-through state, the voltage amplitude to be determined and the high and low voltage fault judgment thresholds.

2. The voltage amplitude calculation method based on high and low voltage ride through fault strategy according to claim 1 is characterized in that: The voltage amplitude to be determined under the high and low voltage ride through fault strategy is calculated based on the equivalent voltage source, the intermediate value related to the reactive current, the resistance-inductance angle and the reactive support coefficient during the high and low voltage ride through, including: Calculate the first voltage phase angle and the second voltage phase angle of the grid connection point voltage leading system according to the equivalent voltage source, the reactive current related intermediate value, the resistance-inductance angle and the reactive support coefficient during the high and low voltage ride-through period; Calculate a first voltage amplitude to be determined according to the reactive current related intermediate value, the resistance-inductance angle, the first voltage phase angle and the reactive support coefficient during the high and low voltage ride-through period; The second voltage amplitude to be determined is calculated according to the reactive current related intermediate value, the resistance-inductance angle, the second voltage phase angle and the reactive support coefficient during the high-low voltage ride-through period.

3. The voltage amplitude calculation method based on high and low voltage ride through fault strategy according to claim 2 is characterized in that: The first voltage amplitude to be determined is calculated according to the reactive current related intermediate value, the resistance-inductance angle, the first voltage phase angle and the reactive support coefficient during the high and low voltage ride-through period, including: The first voltage amplitude to be determined U is calculated according to the following formula d1 : Among them, m is the intermediate value related to the reactive current, α is the resistance-inductance angle, θ1 is the first voltage phase angle, and k is the reactive support coefficient during the high and low voltage ride-through period.

4. The voltage amplitude calculation method based on high and low voltage ride through fault strategy according to claim 2 is characterized in that: The step of calculating the second voltage amplitude to be determined according to the reactive current related intermediate value, the resistance-inductance angle, the second voltage phase angle and the reactive support coefficient during the high and low voltage ride-through period includes: The second voltage amplitude to be determined U is calculated according to the following formula d2 : Among them, m is the intermediate value related to the reactive current, α is the resistance-inductance angle, θ2 is the second voltage phase angle, and k is the reactive support coefficient during the high and low voltage ride-through period.

5. The voltage amplitude calculation method based on high and low voltage ride through fault strategy according to claim 2 is characterized in that: The step of calculating the target voltage amplitude according to the voltage ride-through state, the voltage amplitude to be determined, and the high and low voltage fault judgment thresholds includes: If it is determined that the voltage ride-through state is a high voltage ride-through state, the larger of the first voltage amplitude to be determined and the second voltage amplitude to be determined that are greater than the high and low voltage fault judgment thresholds is used as the target voltage amplitude.

6. The voltage amplitude calculation method based on high and low voltage ride through fault strategy according to claim 2 is characterized in that: The step of calculating the target voltage amplitude according to the voltage ride-through state, the voltage amplitude to be determined, and the high and low voltage fault judgment thresholds includes: If it is determined that the voltage ride-through state is a low voltage ride-through state, the smaller of the first voltage amplitude to be determined and the second voltage amplitude to be determined that are smaller than the high and low voltage fault judgment thresholds is used as the target voltage amplitude.

7. The voltage amplitude calculation method based on high and low voltage ride through fault strategy according to any one of claims 1 to 6, characterized in that: The voltage amplitude calculation method based on the high and low voltage ride-through fault strategy also includes: The voltage amplitude to be determined that is less than or equal to zero is directly regarded as an invalid target voltage amplitude.

8. A voltage amplitude calculation device based on high and low voltage ride-through fault strategy, characterized in that: include: A first calculation unit is used to perform equivalent merging of the system equivalent branch and the high and low voltage fault branches to obtain an equivalent voltage source and an equivalent resistance-inductance system, and calculate the resistance-inductance angle according to the equivalent resistance-inductance system and the angular frequency; A second calculation unit is used to calculate the voltage amplitude to be determined under the high and low voltage ride through fault strategy according to the equivalent voltage source, the intermediate value related to the reactive current, the resistance-inductance angle and the reactive support coefficient during the high and low voltage ride through period; The third calculation unit is used to determine the voltage crossing state according to the numerical interval of the resistance-inductance angle if it is determined that the voltage amplitude to be determined is greater than zero, and calculate the target voltage amplitude according to the voltage crossing state, the voltage amplitude to be determined and the high and low voltage fault judgment thresholds.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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