Fault direction discrimination method, system and medium for outgoing line of inverter power station

Abstract

The present invention discloses a method, system and medium for discriminating the fault direction of the outgoing line of an inverter-type power station, belonging to the technical field of relay protection of power systems. The method includes: Step S1, after a short-circuit fault occurs on the line, collect the voltage and current at the protection installation location; Step S2, calculate the reference value of the positive-sequence reactive current of the inverter-type power source; and calculate the port voltage of the inverter-type power source according to the voltage and current at the protection installation location, and calculate the actually output positive-sequence reactive current of the inverter-type power source according to the current at the protection installation location and the port voltage of the inverter-type power source; Step S3, calculate the Euclidean distance between the actually output positive-sequence reactive current and the reference value of the positive-sequence reactive current, compare the Euclidean distance with the setting value, and determine the fault direction. The present invention solves the problem that the traditional direction element cannot act correctly when a fault occurs in the near area of the outgoing line protection of the inverter-type power station, and improves the accuracy of fault direction judgment.

Description

Technical Field

[0001] The present invention belongs to the technical field of relay protection in power systems, and more specifically, relates to a method, a system and a medium for discriminating the fault direction of outgoing lines of an inverter power station Background Art

[0002] According to the characteristics of energy distribution, photovoltaic and wind power mainly access the power system in the way of large-scale access and centralized transmission

[0003] In the prior art, for the fault direction judgment of inverter power sources such as direct-drive wind turbines and photovoltaics, the traditional direction elements for discriminating the fault direction of synchronous generators are still used. However, the fault characteristics of inverter power sources such as direct-drive wind turbines and photovoltaics are mainly characterized by weak feed, power source impedance change, and unequal positive and negative sequence impedances, which are very different from the fault characteristics of synchronous generators. Directly using the traditional direction elements to judge the fault direction of the outgoing lines of an inverter power station will have the problem of inaccurate judgment due to the influence of different fault ride-through control strategies of the inverter power source Summary of the Invention

[0004] Aiming at the defects and improvement requirements of the prior art, the present invention provides a method, a system and a medium for discriminating the fault direction of outgoing lines of an inverter power station, aiming to provide a fault direction discrimination method that is not affected by different fault ride-through control strategies of the inverter power source and improve the accuracy of fault direction judgment

[0005] To achieve the above object, according to one aspect of the present invention, a method for discriminating the fault direction of outgoing lines of an inverter power station is provided, including

[0006] Step S1: After a short-circuit fault occurs on the line, collect the voltage and current at the protection installation location

[0007] Step S2: Calculate the reference value of the positive-sequence reactive current of the inverter power source; calculate the port voltage of the inverter power source according to the voltage and current at the protection installation location, and calculate the actual output positive-sequence reactive current of the inverter power source according to the current at the protection installation location and the port voltage of the inverter power source

[0008] Step S3: Calculate the Euclidean distance between the actually output positive-sequence reactive current and the reference value of the positive-sequence reactive current, compare the Euclidean distance with the setting value, and determine the fault direction

[0009] Further, for the protection against the inverter power source, if the Euclidean distance is less than the setting value, it is judged that a forward fault has occurred, otherwise it is judged that a reverse fault has occurred

[0010] Further, for the protection against the back-to-back voltage source, if the Euclidean distance is greater than the set value, it is determined that a positive-direction fault has occurred; otherwise, it is determined that a reverse-direction fault has occurred.

[0011] Further, the voltage u at the inverter-type power supply port g is:

[0012]

[0013] In the formula, u and i are the sampled values of the voltage and current at the protection installation location, where u g = [u ga , u gb , u gc T , u = [u a , u b , u c T , i = [i a , i b , i c T , L cs and L cm are the self-inductance and mutual inductance of the collector line respectively, R cs and R cm are the self-resistance and mutual resistance of the collector line respectively, L mt is the equivalent inductance of the main transformer, L st is the equivalent inductance of the box-type transformer, k mt is the turns ratio of the main transformer, k st is the turns ratio of the box-type transformer, and the expression of matrix M is:

[0014] Further, the actual output positive-sequence reactive current is:

[0015]

[0016] Among them, u gα1 , u gβ1 are the α and β components of the positive-sequence voltage at the inverter-type power supply port, and i α1 , i β1 are the α and β components of the positive-sequence current at the protection installation location.

[0017] Further, the reference value of the positive-sequence reactive current of the inverter-type power supply is calculated based on the voltage at the protection installation location, and the calculation method is:

[0018]

[0019] Among them, K Q1 and K Q2 ​​​is the positive-sequence reactive current proportionality coefficient, U PCC1 is the amplitude of the positive-sequence voltage at the protection installation location, I b is the rated current amplitude of the inverter-type power supply station.

[0020] Furthermore, the calculation method of the Euclidean distance is as follows:

[0021]

[0022] where is the Euclidean distance between the actually output positive-sequence reactive current and the positive-sequence reactive current reference value, is the calculated value of the actually output positive-sequence reactive current at time t i moment, is the calculated value of the positive-sequence reactive current reference value at time t i moment, I b is the rated current amplitude of the inverter-type power supply station.

[0023] Furthermore, it also includes calculating the scaled positive-sequence reactive current reference value I Q of the inverter-type power supply, calculating the Euclidean distance between the scaled positive-sequence reactive current reference value I Q and the actually output positive-sequence reactive current, and comparing the Euclidean distance with a set value to determine the fault direction; among them, the scaled positive-sequence reactive current reference value I Q is:

[0024]

[0025] In the formula, t i is each sampling moment at the protection installation location within the time window, k iq is the scaling coefficient, is the set of positive-sequence reactive current reference values of the inverter-type power supply within the time window, I lim is the sum of the short-circuit current limit values of each power supply within the inverter-type power supply station;

[0026] where:

[0027]

[0028] In the formula, is the set of positive-sequence reactive current values actually output by the inverter-type power supply within the time window.

[0029] According to the second aspect of the present invention, there is provided a fault direction discrimination system for the outgoing line of an inverter-type power supply station, including:

[0030] A collection unit, configured to collect the voltage and current at the protection installation location after a short-circuit fault occurs on the line;

[0031] A calculation unit is configured to calculate a positive-sequence reactive current reference value of an inverter power supply; calculate the port voltage of the inverter power supply based on the voltage and current at the protection installation location, and calculate the actual output positive-sequence reactive current of the inverter power supply based on the current at the protection installation location and the port voltage of the inverter power supply.

[0032] A fault direction determination unit is configured to calculate the Euclidean distance between the actually output positive-sequence reactive current and the positive-sequence reactive current reference value, compare the Euclidean distance with a setting value, and determine the fault direction.

[0033] According to the third aspect of the present invention, there is provided a computer-readable storage medium having a computer program stored thereon, and when the program is executed by a processor, it implements the fault direction discrimination method as described in any one of the first aspects.

[0034] Generally speaking, through the above technical solutions conceived by the present invention, the following beneficial effects can be achieved:

[0035] (1) In the fault direction discrimination method of the present invention, by using the voltage, current measured at the protection installation location, and the port voltage of the inverter power supply, the actually output positive-sequence reactive current of the inverter power supply and the positive-sequence reactive current reference value of the inverter power supply are calculated. By comparing the magnitude between the Euclidean distance between the actually output positive-sequence reactive current of the inverter power supply and the positive-sequence reactive current reference value of the inverter power supply and the setting value, the fault occurrence direction is judged. That is to say, this fault direction discrimination method of the present invention is based on the positive-sequence reactive current characteristics of the inverter power supply, is not affected by different fault ride-through control strategies of the inverter power supply, can accurately judge the fault direction, and effectively solves the problem that traditional directional elements cannot operate correctly when a fault occurs in the outgoing line of an inverter power supply station.

[0036] (2) Preferably, the fault discrimination method further includes calculating the scaled positive-sequence reactive current reference value of the inverter power supply, calculating the Euclidean distance between the scaled positive-sequence reactive current reference value and the actually output positive-sequence reactive current, and then determining the fault method, which can avoid problems such as errors in the positive-sequence reactive current reference value caused by factors such as differences in the positive-sequence reactive current proportionality coefficient and the actual grid-connected capacity of the inverter power supply, and further improve the accuracy of fault direction judgment. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a schematic flowchart of a method for discriminating the fault direction of an outgoing line of an inverter power supply station provided by an embodiment of the present invention.

[0038] Figure 2 is a schematic diagram of a typical outgoing line system of an inverter power supply station provided by an embodiment of the present invention.

[0039] Figure 3 When a phase A ground fault occurs at point F1 in the transmission system structure provided by the embodiment of the present invention, the waveforms of the positive-sequence reactive current actually output by the inverter-type power source and the reference value of the positive-sequence reactive current of the inverter-type power source are calculated.

[0040] Figure 4 When a phase A ground fault occurs at point F2 in the transmission system structure provided by the embodiment of the present invention, the waveforms of the positive-sequence reactive current actually output by the inverter-type power source and the reference value of the positive-sequence reactive current of the inverter-type power source are calculated. Detailed implementation manners

[0041] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0042] Aiming at the problem that traditional directional elements cannot operate correctly when a short-circuit fault occurs on the outgoing line of an inverter-type power source substation, the present invention proposes a method for discriminating the fault direction of the outgoing line of an inverter-type power source substation, and this discrimination method can reliably judge the fault direction of the outgoing line of an inverter-type power source substation.

[0043] As Figure 1 shown, it is a schematic flow chart of a method for discriminating the fault direction of the outgoing line of an inverter-type power source substation provided by the embodiment of the present invention, including the following steps:

[0044] Step S1: After a short-circuit fault occurs on the line, collect the voltage and current information at the protection installation location;

[0045] Step S2: Calculate the reference value of the positive-sequence reactive current of the inverter-type power source according to the voltage at the protection installation location;

[0046] Calculate the port voltage of the inverter-type power source according to the voltage and current at the protection installation location; calculate the positive-sequence reactive current actually output by the inverter-type power source according to the current at the protection installation location and the port voltage of the inverter-type power source;

[0047] Step S3: Calculate the Euclidean distance between the actually output positive-sequence reactive current and the reference value of the positive-sequence reactive current, compare the calculated Euclidean distance with the setting value, and determine the fault direction.

[0048] Specifically, in step S1, it further includes sending the collected voltage and current information at the protection installation location to an information processing unit for data processing, and decomposing the voltage and current information at the protection installation location to obtain the positive-sequence voltage information and positive-sequence current information at the protection installation location.

[0049] In an optional embodiment, in step S2, the positive-sequence reactive current reference value is calculated according to the grid connection requirements of the inverter power supply, and the actually output positive-sequence reactive current is calculated according to the positive-sequence voltage at the inverter power supply port and the positive-sequence current at the protection installation location, specifically including:

[0050] The calculation method for the positive-sequence reactive current reference value of the inverter power supply is:

[0051]

[0052] Among them, in formula (1), is the positive-sequence reactive current reference value of the inverter power supply after the fault, K Q1 and K Q2 are positive-sequence reactive current proportionality coefficients, U PCC1 is the amplitude of the positive-sequence voltage at the protection installation location, I b is the amplitude of the rated current of the inverter power supply substation.

[0053] The calculation method for the actually output positive-sequence reactive current of the inverter power supply is:

[0054]

[0055] Among them, in formula (2), is the actually output positive-sequence reactive current of the inverter power supply, u gα1 , u gβ1 are the α and β components of the positive-sequence voltage at the inverter power supply port, i α1 , i β1 are the α and β components of the positive-sequence current at the protection installation location.

[0056] The calculation method for the three-phase voltage at the inverter power supply port (i.e., the voltage at the inverter power supply port) is:

[0057]

[0058] Among them, in formula (3), u g is the three-phase voltage at the inverter port, u and i are the sampled values of the three-phase voltage and current at the protection installation location respectively, u g = [u ga , u gb , u gc T , u = [u a , u b , u c T , i = [i a , i b , i c T , L cs and L​​​cm are the self-inductance and mutual inductance of the current collector, respectively, and R cs and R cm are the self-resistance and mutual resistance of the current collector, respectively, and L mt is the equivalent inductance of the main transformer, and L st is the equivalent inductance of the box-type transformer, and k mt is the transformation ratio of the main transformer, and k st is the transformation ratio of the box-type transformer. The expression of matrix M is:

[0059] In an alternative embodiment, in step S3, the Euclidean distance is calculated between the actually output positive-sequence reactive current and the positive-sequence reactive current reference value, and the calculated Euclidean distance is compared with the set value to determine the fault direction, which specifically includes:

[0060] The calculation method for the Euclidean distance between the actually output positive-sequence reactive current and the positive-sequence reactive current reference value is:

[0061]

[0062] Among them, in formula (4), is the Euclidean distance between the actually output positive-sequence reactive current and the positive-sequence reactive current reference value, is the calculated value of the actually output positive-sequence reactive current at time t i moment, is the calculated value of the positive-sequence reactive current reference value at time t i moment, and I b is the rated current amplitude of the inverter-type power supply station.

[0063] For the protection against the inverter-type power supply, if the calculated Euclidean distance is less than the set value, it is judged that a forward fault has occurred, otherwise it is judged that a reverse fault has occurred; for the protection against the voltage source (i.e., the external system protection), if the calculated Euclidean distance is greater than the set value, it is judged that a forward fault has occurred, otherwise it is judged that a reverse fault has occurred.

[0064] Among them, the set value of the Euclidean distance is between 0 and 1, and 0.2 is recommended.

[0065] As Figure 2 shown, taking the outgoing line system of a typical inverter-type power supply station as an example, the outgoing line system of this inverter-type power supply station includes an inverter-type power supply station 1, a bus 2 behind the inverter-type power supply station, a protection 3 behind the inverter-type power supply station, a transmission line 4, a protection 5 behind the external system, a bus 6 behind the external system, and an external system 7.

[0066] For the above typical outgoing line system of an inverter-type power station, the above method is used to judge the fault direction of the protection 3 (protection M in this embodiment) of the inverter-type power station and the protection 5 (protection N in this embodiment) of the external system.

[0067] In step S2, in order to avoid errors in the positive-sequence reactive current reference value calculated by the protection due to factors such as the difference in the positive-sequence reactive current proportion coefficient and the actual grid-connected capacity of the inverter-type power source, the positive-sequence reactive current reference value at the protection of the inverter-type power station (i.e., protection M) is calculated as the "scaled" positive-sequence reactive current reference value:

[0068]

[0069] Among them, in formula (5), I Q is the "scaled" positive-sequence reactive current reference value, t i is the time for calculating the "scaling" coefficient k iq at each sampling moment at protection M within the time window, I lim is the sum of the short-circuit current limit values of each power source within the inverter-type power station.

[0070] k iq The calculation method is as follows:

[0071]

[0072] Among them, in formula (6), is the set of positive-sequence reactive current reference values of the inverter-type power source within a period of time after the fault, calculated through the above formula (1), t i ={t n -T L +1, t n -T L +2,..., t n}; is the set of actual positive-sequence reactive current values output by the inverter-type power source within a period of time after the fault, T L is the number of protection sampling points within the time window for calculating k iq , and t n is the current sampling moment.

[0073] In this embodiment, the calculation of the actual positive-sequence reactive current output at protection M of the inverter-type power station in step S2 is:

[0074]

[0075] Among them, in formula (7), is the positive-sequence reactive current actually output by the inverter power supply, u gα1 , u gβ1 are the α and β components of the positive-sequence voltage at the inverter power supply port, i mα1 , i mβ1 are the α and β components of the positive-sequence current at protection point M.

[0076] In this embodiment, the calculation of the three-phase voltage at the inverter power supply port of protection point M back to back with the inverter power supply station in step 2 is as follows:

[0077]

[0078] Among them, in formula (8), u g is the three-phase voltage of the inverter port, u m and i m are the sampled values of the three-phase voltage and current at protection point M respectively, u g = [u ga , u gb , u gc T , u m = [u ma , u mb , u mc T , i m = [i ma , i mb , i mc T , L cs and L cm are the self-inductance and mutual inductance of the collector line respectively, R cs and R cm are the self-resistance and mutual resistance of the collector line respectively, L mt is the equivalent inductance of the main transformer, L st is the equivalent inductance of the box-type transformer, k mt is the transformation ratio of the main transformer, k st is the transformation ratio of the box-type transformer. The expression of matrix M is:

[0079] In step 3 of this embodiment, the calculation of the Euclidean distance between the positive-sequence reactive current actually output by the inverter power supply at protection point M and the reference value of the positive-sequence reactive current is as follows:

[0080]

[0081] Among them, in formula (9), is and the average Euclidean distance of the per-unit value of I Q within a certain period of time after the fault, the calculation time window and the calculation of k iq ​​​have the same time window.

[0082] In step 3 of this embodiment, when the calculated Euclidean distance at protection M satisfies it is determined that a forward fault occurs at M, otherwise it is determined as a reverse fault. K i is the setting value of the current direction criterion, set to 0.2.

[0083] In this embodiment, considering the waveform characteristics of the reference value and the response speed of the control system comprehensively, the time window is set to 30 ms.

[0084] Figure 3 are the waveforms of the positive-sequence reactive current actually output by the inverter power supply and the reference value of the positive-sequence reactive current of the inverter power supply calculated according to the measured voltage, current at protection M with an inverter power supply behind, and the voltage at the inverter power supply port when a phase A ground fault occurs at point F1 in the transmission system structure provided by the embodiment of the present invention. The Euclidean distance between the positive-sequence reactive current actually output by the inverter power supply and the positive-sequence reactive current of the inverter power supply is 0.077, which is less than the setting value of 0.2, and the direction element determines it as a forward fault.

[0085] Figure 4 are the waveforms of the positive-sequence reactive current actually output by the inverter power supply and the reference value of the positive-sequence reactive current of the inverter power supply calculated according to the measured voltage, current at protection M with an inverter power supply behind, and the voltage at the inverter power supply port when a phase A ground fault occurs at point F2 in the transmission system structure provided by the embodiment of the present invention. The Euclidean distance between the positive-sequence reactive current actually output by the inverter power supply and the positive-sequence reactive current of the inverter power supply is 1.572, which is greater than the setting value of 0.2, and the direction element determines it as a reverse fault.

[0086] From Figure 3 and Figure 4 it can be seen that the current direction criterion adopted by the present invention has high reliability.

[0087] According to another object of the present invention, the present invention also provides a fault direction discrimination system for the outgoing line of an inverter power supply substation, mainly including:

[0088] An acquisition unit, configured to acquire the voltage and current at the protection installation location after a short-circuit fault occurs on the line;

[0089] A calculation unit, configured to calculate the reference value of the positive-sequence reactive current of the inverter power supply; and calculate the voltage at the inverter power supply port according to the voltage and current at the protection installation location, and calculate the positive-sequence reactive current actually output by the inverter power supply according to the current at the protection installation location and the voltage at the inverter power supply port;

[0090] The fault direction determination unit is used to calculate the Euclidean distance between the actually output positive-sequence reactive current and the reference value of the positive-sequence reactive current, compare the Euclidean distance with the setting value, and determine the fault direction.

[0091] For the protection against the back-to-back inverter-type power source, if the Euclidean distance is less than the setting value, it is determined that a forward fault has occurred; otherwise, it is determined that a reverse fault has occurred.

[0092] For the protection against the back-to-back voltage source, if the Euclidean distance is greater than the setting value, it is determined that a forward fault has occurred; otherwise, it is determined that a reverse fault has occurred.

[0093] Among them, the actually output positive-sequence reactive current and the reference value of the positive-sequence reactive current in the calculation unit, as well as the calculation method of the Euclidean distance in the fault direction determination unit, are the same as the calculation methods in the fault direction discrimination method.

[0094] The present invention also provides a computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, each step in the above-mentioned fault direction discrimination method is implemented.

[0095] In the embodiment of the present invention, by using the measured voltage, current at the protection installation location and the voltage at the inverter-type power source port, the actually output positive-sequence reactive current of the inverter-type power source and the reference value of the positive-sequence reactive current of the inverter-type power source are calculated. According to the comparison between the Euclidean distance between the actually output positive-sequence reactive current of the inverter-type power source and the reference value of the positive-sequence reactive current of the inverter-type power source and the setting value, the fault occurrence direction is judged. The current direction criterion used in the present invention is not affected by different fault ride-through control strategies of the inverter-type power source, can accurately judge the fault direction, and effectively solves the problem that the traditional direction element cannot operate correctly when a fault occurs in the outgoing line of the inverter-type power source substation.

[0096] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for discriminating the fault direction of the outgoing line of an inverter-type power station, characterized in that, Including: Step S1: After a short-circuit fault occurs in the line, collect the voltage and current at the protection installation location; Step S2: Calculate the reference value of the positive-sequence reactive current of the inverter power supply; And calculate the port voltage of the inverter power supply based on the voltage and current at the protection installation location, and calculate the actually output positive-sequence reactive current of the inverter power supply based on the current at the protection installation location and the port voltage of the inverter power supply; Step S3: Calculate the Euclidean distance between the actually output positive-sequence reactive current and the reference value of the positive-sequence reactive current, compare the Euclidean distance with the setting value, and determine the fault direction; It also includes calculating the scaled positive-sequence reactive current reference value of the inverter power supply I Q , calculating the scaled positive-sequence reactive current reference value I Q and the Euclidean distance between the actual output positive-sequence reactive current, and comparing the Euclidean distance with a set value to determine the fault direction; wherein, the scaled positive-sequence reactive current reference value I Q is: Wherein, t i are the sampling moments at the protection installation location within the time window, k iq is the scaling factor, is the set of reference values of the positive-sequence reactive current of the inverter power supply within the time window, I lim is the sum of the short-circuit current limit values of each power supply within the substation of the inverter power supply; Wherein: In the formula, is the set of positive-sequence reactive current values actually output by the inverter power supply within the time window.

2. The fault direction discrimination method according to claim 1, wherein For the protection against the inverter power supply, if the Euclidean distance is less than the setting value, it is determined that a forward fault has occurred, otherwise it is determined that a reverse fault has occurred.

3. The fault direction discrimination method according to claim 1, characterized in that For the protection against the voltage source, if the Euclidean distance is greater than the setting value, it is determined that a forward fault has occurred, otherwise it is determined that a reverse fault has occurred.

4. The fault direction discrimination method according to claim 1, characterized in that, The voltage of the inverter power supply port u g is as follows: Wherein, u and i are respectively the sampled values of the voltage and current at the protection installation location, where u g = u ga , u gb , u gc T , u = u a , u b , u c T , i = i a , i b , i c T , L cs and L cm are respectively the self-inductance and mutual inductance of the collector line, R cs and R cm are respectively the self-resistance and mutual resistance of the collector line, L mt is the equivalent inductance of the main transformer, L st is the equivalent inductance of the box-type transformer, k mt is the transformation ratio of the main transformer, k st is the transformation ratio of the box-type transformer. The expression of the matrix is: .​​​ 5. The fault direction discrimination method according to claim 4, characterized in that, The actual output positive-sequence reactive current is as follows: Among them, , are the α and β components of the positive-sequence voltage of the inverter power supply port, , are the α and β components of the positive-sequence current at the protection installation location.

6. The fault direction discrimination method according to claim 1, wherein The positive-sequence reactive current reference value of the inverter power supply is calculated based on the voltage at the protection installation point, and the calculation method is as follows: Among them, K Q1 and K Q2 are the positive-sequence reactive current proportion coefficients, U PCC1 is the positive-sequence voltage amplitude at the protection installation location, I b is the rated current amplitude of the inverter-type power source station.

7. The fault direction discrimination method according to claim 1, characterized in that The calculation method of the Euclidean distance is: Wherein, is the Euclidean distance between the actual output positive-sequence reactive current and the positive-sequence reactive current reference value, is the calculated value of the actual output positive-sequence reactive current at t i moment, is the calculated value of the positive-sequence reactive current reference value at t i moment, I b is the rated current amplitude of the inverter-type power supply station.

8. An inverter-type power station outgoing line fault direction discrimination system, characterized in that, Including: A collection unit for collecting the voltage and current at the protection installation location after a short-circuit fault occurs in the line; A calculation unit for calculating the reference value of the positive-sequence reactive current of the inverter power supply; And calculating the port voltage of the inverter power supply based on the voltage and current at the protection installation location, and calculating the actually output positive-sequence reactive current of the inverter power supply based on the current at the protection installation location and the port voltage of the inverter power supply; A fault direction determination unit for calculating the Euclidean distance between the actually output positive-sequence reactive current and the reference value of the positive-sequence reactive current, comparing the Euclidean distance with the setting value, and determining the fault direction; It also includes calculating the positive-sequence reactive current reference value after scaling of the inverter power supply I Q , calculating the positive-sequence reactive current reference value after scaling I Q and the Euclidean distance between the positive-sequence reactive current actually output, and comparing the Euclidean distance with a set value to determine the fault direction; wherein, the positive-sequence reactive current reference value after scaling I Q is as follows: Wherein, t i are the sampling moments at the protection installation location within the time window, k iq is the scaling factor, is the set of positive-sequence reactive current reference values of the inverter-type power source within the time window, I lim is the sum of the short-circuit current limit values of each power source within the substation of the inverter-type power source; Wherein: Wherein, is the set of positive-sequence reactive current values actually output by the inverter power supply within the time window.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by a processor, it implements the fault direction discrimination method according to any one of claims 1-7.

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