Doubly-fed new energy power supply station current collection line outlet fault direction discrimination method

Abstract

The invention discloses a doubly-fed new energy power station current collection line outlet fault direction discrimination method, and belongs to the technical field of power system relay protection. The method comprises the following steps: acquiring a three-phase measurement voltage within a period of time before a fault of a current collection line protection installation position and a three-phase measurement voltage and a measurement current at the protection installation position after the fault; constructing a memory voltage sequence according to the measurement voltage sequence of each phase before the fault at the protection installation position, and further constructing a differential sequence of the measurement current; bringing the measurement voltage of each phase and the inter-phase voltage at the protection installation position after the fault into a phase selection criterion, and determining the type and phase of the fault; and finally, calculating waveform correlation coefficients of the memory voltage sequence and the measurement current differential sequence of the fault phase, and substituting the waveform correlation coefficients into a preset criterion to judge the direction of the outlet fault. The method can effectively solve the problem that when the outlet of the doubly-fed new energy power station current collection line fails, the direction element of 90-degree wiring cannot accurately judge the fault direction.

Description

Technical Field

[0001] The present invention relates to the technical field of relay protection for power systems, and particularly to a method for discriminating the fault direction at the outlet of the collector line of a doubly-fed new energy power source station. Background Art

[0002] The development of new energy power generation technology in China is rapid, and the installed capacity of new energy power generation represented by wind power and photovoltaic power continues to rise. As of the end of September 2024, the installed capacity of renewable energy nationwide reached 1.73 billion kilowatts, accounting for about 54.7% of China's total installed capacity. Among them, the installed capacity of wind power was 480 million kilowatts, and the installed capacity of solar power generation was 770 million kilowatts. The installed capacity of wind power and solar power generation reached 1.25 billion kilowatts, accounting for 39.5% of the total installed capacity.

[0003] In this context, the proportion of new energy power sources in the power system is increasing day by day. When a fault occurs in the new energy power generation grid-connected area, the fault characteristics such as the weak feed characteristics, high harmonics, and frequency deviation characteristics shown by a large number of new energy power sources under rapid response and the interaction of multiple controlled devices, as well as the instability of the system impedance, and the complex electromagnetic and control response processes make the fault characteristics in the new energy power generation grid-connected area significantly different from those of traditional power systems, and pose a risk of failure to traditional AC line protection based on power frequency quantities. When a fault occurs in the near area of the outlet of the collector line of a doubly-fed new energy power source station, the 90° wiring direction element in the currently widely configured directional overcurrent protection of the collector line is difficult to accurately discriminate the fault direction, seriously threatening the safe and stable operation of the power system.

[0004] In view of this, a method for discriminating the fault direction at the outlet of the collector line of a doubly-fed new energy power source station is needed. Summary of the Invention

[0005] In view of the above defects or improvement requirements of the prior art, the present invention provides a method for discriminating the fault direction at the outlet of the collector line of a doubly-fed new energy power source station based on memory voltage and current differential, aiming to solve the problem of misjudgment of the 90° wiring direction element in the existing directional overcurrent protection. The specific technical solutions are as follows:

[0006] A method for discriminating the fault direction at the outlet of the collector line of a doubly-fed new energy power source station, comprising the following steps:

[0007] S1: When a fault occurs in the collector line of a doubly-fed new energy power source station, obtain the three-phase measured voltages at the protection installation of the collector line for a period of time before the fault and the three-phase measured voltages and measured currents at the protection installation after the fault;

[0008] S2: Construct a memory voltage sequence according to the measured voltage sequences of each phase before the fault at the protection installation;

[0009] S3: Construct a differential sequence of the measured current according to the sequence of the measured currents of each phase after a fault at the protection installation location.

[0010] S4: Select the measured voltages of each phase and the inter-phase voltages at the protection installation location after the fault and bring them into the phase selection criterion to determine the fault type and phase.

[0011] S5: Select an appropriate data window, calculate the waveform correlation coefficient between the memory voltage sequence of the fault phase and the differential sequence of the measured current, and use it as the input for the criterion of the fault direction at the outlet.

[0012] S6: Substitute the waveform correlation coefficient into the preset criterion to determine the direction of the fault at the outlet.

[0013] Preferably, in S1, the protection installation location of the collector line is on the side of the collecting bus of each collector line and is not configured on the side of the new energy unit.

[0014] Preferably, the construction method of the memory voltage sequence is as follows:

[0015] Use the formula to calculate the memory voltage of each phase, where is the memory voltage at the protection installation location at time t after the fault, is the measured voltage corresponding to the time T w1 before this moment, and T w1 should be an integer multiple of the power frequency period; the time t should satisfy 0 ≤ t - t f ≤ T w1 , that is, it should be within T f after the fault time t w1 .

[0016] According to the formula calculate the memory voltage between each phase

[0017] Preferably, the construction method of the differential sequence of the measured current is as follows:

[0018] Use the forward difference formula to construct the differential sequence of each phase current: where is the differential sequence of the measured current of each phase constructed, is the measured current of each phase at the protection installation location at time t after the fault,

[0019] According to the formula calculate the differential sequence of the measured current between each phase

[0020] Preferably, the method for determining the fault type and phase is as follows:

[0021] The instantaneous value integration algorithm is used to calculate the modulus sum of the phase voltages and the phase - to - phase voltages at the installation location of each outgoing protection of the collector lines within half a cycle after the fault, and the modulus sum of the memory voltage half - cycle corresponding to a power frequency cycle before this interval, and calculate the ratio of the two, that is:

[0022]

[0023]

[0024] In the formula, t f is the fault time, T is the power frequency cycle, N is the number of protection sampling points within a power frequency cycle, and Δt is the sampling interval; u a (t), u b (t), u c (t) are the instantaneous values of the phase - measured voltages at time t, and u ab (t), u bc (t), u ca (t) are the instantaneous values of the phase - to - phase measured voltages at time t, where and are the threshold values of the ratio of the modulus sums of the phase voltage and the phase - to - phase voltage respectively;

[0025] If either of the above two formulas is satisfied, it is considered that a fault occurs in the near - zone of the collector line outlet. If formula (2) is satisfied, it is determined as a phase - to - phase fault, and the two phases corresponding to the minimum modulus sum ratio are determined as the fault phases; otherwise, it is determined as a single - phase fault, and the phase corresponding to the minimum modulus sum ratio is determined as the fault phase.

[0026] Preferably, the S5 includes:

[0027] Determine the fault - phase memory voltage sequence u m (t) and the fault - phase measured current differential sequence diff(t) according to the phase - selection result of S4. If it is a single - phase fault, then u m (t) should take diff(t) should take If it is a phase - to - phase fault, then u m (t) should take diff(t) should take

[0028] Calculate the correlation coefficient of the fault - phase memory voltage sequence and the fault - phase measured current differential sequence. Put the fault - phase memory voltage sequence and the fault - phase measured current differential sequence within the time window from t - T w2 to t into sets U1 and U2 respectively, that is, U1 = {u m (t - T w2 +Δt), …, u m (t - Δt), um (t)} and U2 = {diff(t - T w2 +Δt), …, diff(t - Δt), diff(t)}. Put the corresponding elements in sets U1 and U2 into set U, that is, U = {(u x1 , u y1 ), (u x2 , u y2 ) …, (u xn , u yn )}, where u x1 : u xn are the 1 - nth elements of the fault - phase memory voltage sequence in set U1, u y1 : u yn are the 1 - nth elements of the fault - phase measured current differential sequence in set U2, T w2 is the time window of the correlation coefficient algorithm, and n is the number of sampling points corresponding to the time window T w2 , that is, the sequence length. Therefore, substitute the data in the two sequences of u x1 : u xn and u y1 : u yn into the Kendall rank correlation coefficient calculation formula: for calculation, and the Kendall rank correlation coefficient τ(t) of the two sequences within the time window [t - T w2 , t] can be solved.

[0029] Preferably, the discrimination method for the outlet fault is:

[0030] Select appropriate time windows T w3 , T w4 and correlation coefficient setting values τ 1set and τ 2set , where τ 1set is the correlation coefficient setting value with relatively strict conditions, corresponding to a relatively short - duration fixed time window T w3 ; τ 2set is the correlation coefficient setting value with relatively loose conditions, corresponding to a relatively long - duration sliding time window T w4 ; if within T w3 after the cross - window data ends, that is, in [t f +T w2 , t f +T w2 +T w3 , it is continuously satisfied that τ(t) > τ 1set , then it is judged as a positive - direction outlet fault; if this condition is not met, and within T w1 after the fault occurs, there exists a moment t, and within the time window [t - T w4 , t], it is continuously satisfied that τ(t) > τ2set It is also determined as a positive-direction outlet fault. If neither of the two conditions is met, it is determined as a negative-direction outlet fault.

[0031] A computer-readable storage medium, the computer-readable storage medium includes a stored program, wherein, when the program runs, it controls the device where the computer-readable storage medium is located to execute the above-mentioned method for discriminating the outlet fault direction of the collector line of a doubly-fed new energy power station.

[0032] A processor, the processor is used to run a program, wherein, when the program runs, it executes the above-mentioned method for discriminating the outlet fault direction of the collector line of a doubly-fed new energy power station.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] When a fault occurs in the collector line of a doubly-fed new energy power station, the present invention obtains the three-phase measured voltages during a period of time before the fault at the protection installation of the collector line and the three-phase measured voltages and measured currents at the protection installation after the fault; constructs a memory voltage sequence according to the measured voltage sequences of each phase before the fault at the protection installation; constructs a differential sequence of the measured current according to the measured current sequences of each phase after the fault at the protection installation; selects the measured voltages and inter-phase voltages of each phase at the protection installation after the fault into the phase selection criterion to determine the fault type and phase; finally selects a suitable data window, calculates the waveform correlation coefficient between the memory voltage sequence and the differential sequence of the measured current of the fault phase, as the input of the outlet fault direction criterion, and brings the waveform correlation coefficient into the preset criterion to discriminate the direction of the outlet fault. The method for discriminating the outlet fault direction of the collector line of a doubly-fed new energy power station based on memory voltage and current differential proposed by the present invention can effectively solve the problem that the 90° wiring direction element cannot accurately discriminate the fault direction when a fault occurs at the outlet of the collector line of a doubly-fed new energy power station, and improve the reliability of the direction element of the collector line. Description of the Drawings

[0035] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts do not necessarily draw according to the actual scale.

[0036] Figure 1 It is a schematic diagram of the structure of the grid-connected area of a doubly-fed new energy power station provided by an embodiment of the present invention;

[0037] Figure 2In an embodiment of the present invention, a three-phase short-circuit fault occurs at the reverse outlet F2 of the collector line 1 of a new energy power station. The phase comparison value result of the 90° wiring direction element is adopted for the protection of the collector line 1. At 21 ms after the fault, the phase comparison value results of each phase enter the action range of -45° to 135°. Moreover, the short-circuit current at the outlet of the collector line 1 is provided by the new energy power source and has exceeded the setting value, which will cause misoperation of the protection;

[0038] Figure 3 In an embodiment of the present invention, a three-phase short-circuit fault occurs at the forward outlet F1 of the collector line 1 of a new energy power station. It is a comparison diagram of the fault-phase memory voltage and the differential component of the measured current at the installation location of the protection of the collector line 1. Considering the convenience of waveform comparison, each quantity before and after the fault is normalized under the corresponding state. At this time, the collector line 1 is the fault line;

[0039] Figure 4 In an embodiment of the present invention, a three-phase short-circuit fault occurs at the forward outlet F1 of the collector line 1 of a new energy power station. The waveform correlation coefficient τ(t) calculated by the method of the present invention is adopted for the protection of the collector line 1. At this time, the collector line 1 is the fault line;

[0040] Figure 5 In an embodiment of the present invention, a three-phase short-circuit fault occurs at the forward outlet F2 of the collector line 2 of a new energy power station. It is a comparison diagram of the fault-phase memory voltage and the differential component of the measured current at the installation location of the protection of the collector line 1. Considering the convenience of waveform comparison, each quantity before and after the fault is normalized under the corresponding state. At this time, the collector line 1 is the non-fault line;

[0041] Figure 6 In an embodiment of the present invention, a three-phase short-circuit fault occurs at the forward outlet F2 of the collector line 2 of a new energy power station. The waveform correlation coefficient τ(t) calculated by the method of the present invention is adopted for the protection of the collector line 1. At this time, the collector line 1 is the non-fault line;

[0042] Figure 7 In an embodiment of the present invention, a two-phase short-circuit fault occurs at the forward outlet F1 of the collector line 1 of a new energy power station. It is a comparison diagram of the fault-phase memory voltage and the differential component of the measured current at the installation location of the protection of the collector line 1. Considering the convenience of waveform comparison, each quantity before and after the fault is normalized under the corresponding state. At this time, the collector line 1 is the fault line;

[0043] Figure 8 In an embodiment of the present invention, a two-phase short-circuit fault occurs at the forward outlet F1 of the collector line 1 of a new energy power station. The waveform correlation coefficient τ(t) calculated by the method of the present invention is adopted for the protection of the collector line 1. At this time, the collector line 1 is the fault line;

[0044] Figure 9In an embodiment of the present invention, a comparison diagram of the fault-phase memory voltage and the differential component of the measured current at the protection installation of the collector line 1 when a two-phase short-circuit fault occurs at the positive outlet F2 of the collector line 2 of the new energy power station. Considering the convenience of waveform comparison, each quantity before and after the fault is normalized under the corresponding state. At this time, the collector line 1 is a non-faulty line;

[0045] Figure 10 In an embodiment of the present invention, when a two-phase short-circuit fault occurs at the positive outlet F2 of the collector line 2 of the new energy power station, the waveform correlation coefficient τ(t) calculated by the method of the present invention for the protection of the collector line 1. At this time, the collector line 1 is a non-faulty line. Detailed implementation manners

[0046] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0047] It should be understood that when used in this specification and the appended claims, the terms "comprises" and "comprising" indicate the presence of the described features, wholes, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0048] It should also be understood that the terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0049] It should be further understood that the term " / and / " used in the specification of the present invention and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0050] In an embodiment of the present invention, a method for discriminating the fault direction at the outlet of the collector line based on the memory voltage and current differential applicable to a doubly-fed new energy power station is provided, including:

[0051] S1: When a fault occurs in the collector line of the doubly-fed new energy power station, obtain the three-phase measured voltages during a period of time before the fault and the three-phase measured voltages and measured currents at the protection installation after the fault at the protection installation of the collector line;

[0052] S2: Construct a memory voltage sequence based on the pre-fault phase measurement voltage sequences at the protection installation location;

[0053] S3: Construct a differential sequence of the measured current based on the post-fault phase measurement current sequences at the protection installation location;

[0054] S4: Select the post-fault phase measurement voltages and the line-to-line voltages at the protection installation location and bring them into the phase selection criterion to determine the fault type and phase;

[0055] S5: Select an appropriate data window and calculate the waveform correlation coefficient between the memory voltage sequence and the differential sequence of the measured current of the fault phase, which is used as the input for the outlet fault direction criterion;

[0056] S6: Substitute the waveform correlation coefficient into the preset criterion to discriminate the direction of the outlet fault.

[0057] In one of the embodiments, the S2 includes:

[0058] Use the formula to calculate the memory voltage of each phase, where is the memory voltage at the protection installation location at time t after the fault, is the measured voltage corresponding to the time T w1 before this time, and T w1 should be an integer multiple of the power frequency period; the time t should satisfy 0 ≤ t - t f ≤ T w1 , that is, it should be within T f after the fault time t w1 .

[0059] Furthermore, calculate the memory voltage between phases according to the formula

[0060] In this example, T w1 takes two power frequency periods, that is, 40 ms.

[0061] In one of the embodiments, the S3 includes:

[0062] Use the forward difference formula to construct the differential sequence of each phase current: where is the differential sequence of the measured current of each phase constructed, is the measured current of each phase at the protection installation location at time t after the fault,

[0063] Furthermore, calculate the differential sequence of the measured current between phases according to the formula ​​

[0064] In one of the embodiments, the method for determining the fault type and phase in S4 is as follows:

[0065] The modulus sum of the phase voltages and the line-to-line voltages at the installation location of the outlet protection of each collector line within half a cycle after the fault and the half-cycle modulus sum of the memory voltage one power frequency cycle before this interval are calculated using the instantaneous value integration algorithm, and the ratio of the two is calculated, i.e.:

[0066]

[0067] In the formula, t f is the fault time, T is the power frequency cycle, N is the number of protection sampling points within one power frequency cycle, and Δt is the sampling interval; u a (t), u b (t), u c (t) are the instantaneous values of the phase measurement voltages at time t, and u ab (t), u bc (t), u ca (t) are the instantaneous values of the line-to-line measurement voltages at time t, where and are the threshold values of the ratio of the modulus sums of the phase voltage and the line-to-line voltage respectively.

[0068] If either of the above two formulas is satisfied, it is considered that a fault occurs in the near area of the outlet of the collector line. If formula (2) is satisfied, it is determined as a line-to-line fault, and the two phases corresponding to the minimum modulus sum ratio are determined as the fault phases; otherwise, it is determined as a single-phase fault, and the phase corresponding to the minimum modulus sum ratio is determined as the fault phase.

[0069] In this example, take 0.1, take 0.1.

[0070] In one of the embodiments, S5 includes:

[0071] Determine the fault phase memory voltage sequence u m (t) and the measured current differential sequence diff(t) at the protection installation location according to the phase selection result of S4. If it is a single-phase fault, then u m (t) should take diff(t) should take If it is a line-to-line fault, then u m (t) should take diff(t) should take

[0072] Calculate the correlation coefficient between the fault phase memory voltage sequence and the fault phase measured current differential sequence. The time window t - T w2The fault phase memory voltage sequence and the fault phase measured current differential sequence within the time period up to time t are respectively placed into sets U1 and U2, that is, U1 = {u m (t - T w2 + Δt), …, u m (t - Δt), u m (t)} and U2 = {diff(t - T w2 + Δt), …, diff(t - Δt), diff(t)}. The corresponding elements in sets U1 and U2 are placed into set U, that is, U = {(u x1 , u y1 ), (u x2 , u y2 ) …, (u xn , u yn )}, where u x1 : u xn is the 1 - nth element of the fault phase memory voltage sequence in set U1, u y1 : u yn is the 1 - nth element of the fault phase measured current differential sequence in set U2, T w2 is the time window of the correlation coefficient algorithm, and n is the number of sampling points corresponding to the time window T w2 , that is, the sequence length. Therefore, the data in the two sequences of u x1 : u xn and u y1 : u yn are substituted into the Kendall rank correlation coefficient calculation formula: for calculation, and the Kendall rank correlation coefficient τ(t) within the time period from t - T w2 to t can be solved.

[0073] In the formula, sign(·) is the sign function, represents the difference between the number of pairs of elements satisfying consistency and the number of pairs of elements not satisfying consistency in set C; where m1 is the number of subsets composed of the same elements in set U1, z c is the number of elements included in the c - th subset; where m2 is the number of subsets composed of the same elements in set U2, w d is the number of elements included in the d - th subset. If there are no identical elements between the two sequences corresponding to the current time window, the formula can be simplified to

[0074] In this embodiment, T w2 is taken as 10 ms, that is, n = 40.

[0075] In one of the embodiments, the S6 includes:

[0076] Select an appropriate time window T w3 , T w4 and the correlation coefficient threshold value τ 1set and τ 2set . Among them, τ 1set is the correlation coefficient threshold value with relatively strict conditions, corresponding to the fixed time window T with a relatively short duration w3 ; τ 2set is the correlation coefficient threshold value with relatively loose conditions, corresponding to the sliding time window T with a relatively long duration w4 . If within T w3 after the cross-window data ends, that is, within [t f +T w2 , t f +T w2 +T w3 , τ(t) > τ 1set is continuously satisfied, then it is determined as a positive-direction outlet fault; if this condition is not met, and within T w1 after the fault occurs, there exists a moment t such that within the time window [t - T w4 , t], τ(t) > τ 2set is continuously satisfied, it is also determined as a positive-direction outlet fault. If neither condition is met, it is determined as a negative-direction outlet fault.

[0077] In this embodiment, T w3 is taken as 5 ms, τ 1set is taken as 0.8, T w4 is taken as 10 ms, and τ 2set is taken as 0.5.

[0078] Generally speaking, compared with the prior art through the above technical solutions conceived by the present invention, the method for discriminating the fault direction of the outlet of the collector line of a doubly-fed new energy power station based on the memory voltage and current differential proposed by the present invention can effectively solve the problem that the 90° wiring direction element cannot accurately discriminate the fault direction when a fault occurs at the outlet of the collector line of a doubly-fed new energy power station, and improve the reliability of the direction element of the collector line.

[0079] Those of ordinary skill in the art can realize that the units of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components of each example have been generally described according to their functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0080] In the embodiments provided by the present invention, it should be understood that the division of units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units can be combined into one unit, one unit can be split into multiple units, or some features can be ignored, etc.

[0081] In addition, each functional unit in each embodiment of the present invention can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

[0082] If the above-mentioned integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that makes a contribution to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: various media such as USB flash drives, read-only memories (ROMs), random access memories (RAMs), mobile hard disks, magnetic disks, or optical discs that can store program codes.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of each embodiment of the present invention, and they should all be covered by the scope of the claims and the description of the present invention.

Claims

1. A method for discriminating the fault direction at the outlet of the collector line of a doubly-fed new energy power supply station, characterized in that, It includes the following steps: S1: When a fault occurs in the collector line of a doubly-fed new energy power source station, obtain the three-phase measured voltages at the protection installation of the collector line for a period of time before the fault, as well as the three-phase measured voltages and measured currents at the protection installation after the fault; S2: Construct a memory voltage sequence according to the measured voltage sequences of each phase before the fault at the protection installation; S3: Construct a differential sequence of the measured current according to the measured current sequences of each phase after the fault at the protection installation; S4: Select the measured voltages of each phase and the line-to-line voltages at the protection installation after the fault and bring them into the phase selection criterion to determine the fault type and phase; S5: Select an appropriate data window, calculate the waveform correlation coefficient between the memory voltage sequence and the differential sequence of the measured current of the fault phase, and use it as the input of the criterion for judging the direction of the outlet fault; S6: Substitute the waveform correlation coefficient into the preset criterion to judge the direction of the outlet fault.

2. A method for judging the fault direction at the outlet of the collector line of a doubly-fed new energy power source station according to claim 1, characterized in that In S1, the installation position of the collector line protection is on the side of the converging bus of each collector line and is not configured on the side of the new energy unit.

3. A method for discriminating the fault direction at the outlet of the collector line of a doubly-fed new energy power source station according to claim 1, characterized in that The method for constructing the memory voltage sequence is: Calculate the memory voltage of each phase using the formula , where is the memory voltage at the protection installation location at time t after the fault, is the measured voltage corresponding to time T w1 before this time, and T w1 should be an integer multiple of the power frequency period; time t should satisfy 0 ≤ t - t f ≤ T w1 , that is, it should be within T f after the fault time t w1 , According to the formula calculate the memory voltage between each phase 4. A method for discriminating the fault direction at the outlet of the collector line of a doubly-fed new energy power source station according to claim 1, characterized in that, The method for constructing the differential sequence of the measured current is: Construct the differential sequence of each phase current using the forward difference formula: where is the differential sequence of the measured current of each phase constructed, is the measured current of each phase at the protection installation location at time t after the fault, According to the formula Calculate the differential sequence of the measured currents between phases 5. A method for discriminating the fault direction at the outlet of the collector line of a doubly-fed new energy power source station according to claim 1, characterized in that, The method for determining the fault type and phase is: Use the instantaneous value integration algorithm to calculate the modulus sum of the three-phase voltages and line-to-line voltages at the protection installation of each collector line outlet within half a cycle after the fault and the half-cycle modulus sum of the memory voltage one power frequency cycle before this interval, and calculate the ratio of the two, that is: where t f is the fault time, T is the power frequency period, N is the number of protection sampling points within one power frequency period, and Δt is the sampling interval; u a (t), u b (t), u c (t) are the instantaneous values of the measured phase voltages at time t, and u ab (t), u bc (t), u ca (t) are the instantaneous values of the measured inter-phase voltages at time t, where and are the threshold values of the ratio of the modulus of the phase voltage and the inter-phase voltage respectively; If any one of the above two formulas is satisfied, it is considered that a fault occurs in the near area of the collector line outlet. If formula (2) is satisfied, it is determined as a line-to-line fault, and the two phases corresponding to the minimum modulus sum ratio are determined as the fault phases; otherwise, it is determined as a single-phase fault, and the phase corresponding to the minimum modulus sum ratio is determined as the fault phase.

6. A method for discriminating the fault direction at the outlet of the collector line of a doubly-fed new energy power station according to claim 1, characterized in that, S5 includes: Determine the fault phase memory voltage sequence u m (t) and the differential sequence diff(t) of the fault phase measured current at the protection installation location; if it is a single-phase fault, then u m (t) should take diff(t) should take If it is an inter-phase fault, then u m (t) should take diff(t) should take Calculate the correlation coefficient of the fault phase memory voltage sequence and the fault phase measured current differential sequence; from time window t - T w2 to the fault phase memory voltage sequence and the fault phase measured current differential sequence within the time period from t - T m (t - T w2 + Δt), …, u m (t - Δt), u m (t) and U2 = {diff(t - T w2 + Δt), …, diff(t - Δt), diff(t)}; put the corresponding elements in sets U1 and U2 into set U, that is, U = {(u x1 , u y1 ), (u x2 , u y2 ) …, (u xn , u yn )}, where u x1 : u xn are the 1 - nth elements of the fault phase memory voltage sequence in set U1, u y1 : u yn are the 1 - nth elements of the fault phase measured current differential sequence in set U2, T w2 is the time window of the correlation coefficient algorithm, and n is the number of sampling points corresponding to the time window T w2 , that is, the sequence length; Take u x1 : u xn and u y1 : u yn Substitute the data in the two sequences into the Kendall rank correlation coefficient calculation formula: Perform the calculation to solve for the Kendall rank correlation coefficient τ(t) of the two sequences within the time window [t - T w2 , t].

7. A method for discriminating the fault direction at the outlet of the collector line of a doubly-fed new energy power source station according to claim 1, characterized in that, The method for judging the outlet fault is: Select an appropriate time window T w3 , T w4 and the setting value of the correlation coefficient τ 1set and τ 2set , where τ 1set is the setting value of the correlation coefficient with relatively strict conditions, corresponding to the fixed time window T with a relatively short duration w3 ; τ 2set is the setting value of the correlation coefficient with relatively loose conditions, corresponding to the sliding time window T with a relatively long duration w4 ; If within T w3 after the cross-window data ends, that is, within [t f +T w2 , t f +T w2 +T w3 , τ(t) > τ 1set is continuously satisfied, then it is judged as a positive-direction exit fault; if this condition is not met, and within T w1 after the fault occurs, there exists a moment t such that within the time window [t - T w4 , t], τ(t) > τ 2set is continuously satisfied, it is also judged as a positive-direction exit fault; if neither condition is met, it is judged as a negative-direction exit fault.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, wherein when the program runs, it controls the device where the computer-readable storage medium is located to execute the method for judging the direction of the outlet fault of the collector line of a doubly-fed new energy power source station according to any one of claims 1 to 7.

9. A processor, characterized in that, The processor is used to run the program, wherein when the program runs, it executes the method for judging the direction of the outlet fault of the collector line of a doubly-fed new energy power source station according to any one of claims 1 to 7.

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