A DC transmission line fault simulation method and device based on PSS / E

Abstract

The present invention discloses a method and device for simulating faults of a direct current transmission line based on PSS / E, wherein the method comprises: constructing a T-type equivalent circuit model of a direct current transmission line in PSS / E; selecting a fault branch and judging whether the fault branch is enabled; if the fault branch is enabled, obtaining the derivative of the current in the smoothing reactor and the direct current transmission line reactor with respect to time according to the loop formed by the fault branch and the T-type equivalent circuit and the pre-selected positive current direction, so as to obtain the current value in the direct current transmission line; if the fault branch is not enabled, respectively calculating the derivative of the current in the smoothing reactor with respect to time according to the T-type equivalent circuit and the pre-selected positive current direction, so as to obtain the current value in the direct current transmission line. By constructing a T-type equivalent circuit and selecting a fault branch, calculating the current of each branch according to the loop formed by the two, accurately simulating the calculation of direct current and direct voltage, and providing technical support for system research and stable operation.

Description

Technical Field

[0001] The present invention relates to the technical field of power system simulation, and in particular to a method and device for simulating faults of a direct current transmission line based on PSS / E. Background Art

[0002] Although the development and application of high-voltage direct current transmission technology has solved the problem of unbalanced distribution of energy and power load, with the commissioning of more direct current projects and the increase in transmission distances, direct current transmission lines are facing more and more problems. Factors including man-made accidents, differences in geographical environments, and natural force majeure may damage transmission lines, posing a huge threat to the safe operation of the power system.

[0003] Faced with many problems, the simulation of DC line faults in DC engineering joint commissioning tests and safety and stability calculations is very important and indispensable. At present, the existing DC models provided by the PSS / E simulation tool do not have a complete DC fault restart function. In the system stability analysis and calculation, the impact of the DC model on the AC network can only be studied by manually switching between unlocking and locking. When simulating the DC line fault restart function through the manual switching method of unlocking-locking-unlocking, on the one hand, the operation is complicated, and the test personnel must have a full understanding of the timing of the restart logic; on the other hand, when simulating through manual switching, only the impact of the DC model on the AC network can be studied, and the electrical quantity changes of the DC model during the restart process cannot be accurately reflected. Summary of the invention

[0004] The purpose of the embodiment of the present invention is to provide a method and device for simulating a DC transmission line fault based on PSS / E. By building a T-type equivalent circuit in the DC transmission line and selecting a fault branch, the current of each branch is calculated according to a loop formed by each branch in the T-type equivalent circuit and the selected fault branch. The calculation of the DC current and DC voltage in the DC transmission system after the DC transmission line fault can be accurately simulated, which provides technical support for system research and stable operation, realizes the coordination of the restart logic of the DC transmission control and protection system and the safe and stable control system, and ensures the safe and stable operation of the power system.

[0005] To solve the above technical problems, a first aspect of an embodiment of the present invention provides a DC transmission line fault simulation method based on PSS / E, comprising the following steps:

[0006] Build a T-type equivalent circuit model of a DC transmission line in PSS / E;

[0007] Selecting a faulty branch and determining whether the faulty branch is enabled;

[0008] If the fault branch is enabled, the time derivative of the current in the smoothing reactor and the DC transmission line reactance is obtained according to the loop formed by the fault branch and the T-type equivalent circuit and the pre-selected positive direction of the current, so as to obtain the current value in the DC transmission line;

[0009] If the fault branch is not enabled, the derivative of the current in the smoothing reactor with respect to time is calculated according to the T-type equivalent circuit and the pre-selected positive direction of the current to obtain the current value in the DC transmission line;

[0010] The current and the time derivative of the current in the reactance of the DC transmission line are the same as the current and the time derivative of the current in the smoothing reactor.

[0011] Furthermore, the DC transmission line fault simulation method based on PSS / E also includes:

[0012] According to the current value in the DC transmission line, a DC voltage, active power and / or reactive power in the DC transmission line is obtained.

[0013] Further, the determining whether the fault branch is enabled includes:

[0014] Determine whether a ground fault occurs at the head end of the DC transmission line and whether the DC current transmission direction is from the rectifier station to the inverter station;

[0015] When a ground fault occurs at the head end of the DC transmission line and the DC current transmission direction is from the rectifier station to the inverter station, the time derivatives of the current in the smoothing reactor and the DC transmission line reactor are respectively:

[0016]

[0017]

[0018] When a ground fault occurs at the head end of the DC transmission line and the DC current transmission direction is not from the rectifier station to the inverter station, the time derivatives of the current in the smoothing reactor and the DC transmission line reactor are respectively:

[0019]

[0020]

[0021] When there is no ground fault at the head end of the DC transmission line and the DC current is transmitted from the rectifier station to the inverter station, the derivatives of the current in the smoothing reactor with respect to time are respectively:

[0022]

[0023] When no ground fault occurs at the head end of the DC transmission line and the DC current transmission direction is not from the rectifier station to the inverter station, the time derivatives of the current in the smoothing reactor are respectively:

[0024]

[0025] Among them, i LS_R is the current close to the smoothing reactor on the rectifier side, u DC_R is the DC voltage on the rectifier side, R RS_R is the resistance of the smoothing reactor, L LC_R is the commutation reactance on the rectifier side, L LS_R is the reactance of the smoothing reactor, i L_R is the current flowing through the DC line, u C_C is the DC line to ground branch capacitance voltage, i C_C is the current flowing through the DC line to the ground branch, R R_C is the DC line to ground branch resistance, R R_R is the DC line resistance, L L_R is the DC line reactance.

[0026] Furthermore, when a ground fault occurs at the head end of the DC transmission line, the current value of the smoothing reactor and the current value in the DC transmission line reactor are respectively:

[0027]

[0028]

[0029] When there is no ground fault at the head end of the DC transmission line, the current value of the smoothing reactor is:

[0030]

[0031] Accordingly, a second aspect of an embodiment of the present invention provides a DC transmission line fault simulation device based on PSS / E, comprising:

[0032] Model building module, which is used to build a T-type equivalent circuit model of a DC transmission line in PSS / E;

[0033] A selection and judgment module is used to select a fault branch and judge whether the fault branch is enabled;

[0034] A first calculation module, which is used to obtain the time derivative of the current in the smoothing reactor and the DC transmission line reactance according to the loop formed by the fault branch and the T-type equivalent circuit and the pre-selected positive direction of the current when the fault branch is enabled, so as to obtain the current value in the DC transmission line;

[0035] A second calculation module, which is used to calculate the derivative of the current in the smoothing reactor with respect to time according to the T-type equivalent circuit and the pre-selected positive direction of the current when the fault branch is not enabled, so as to obtain the current value in the DC transmission line;

[0036] The current and the time derivative of the current in the reactance of the DC transmission line are the same as the current and the time derivative of the current in the smoothing reactor.

[0037] Furthermore, the DC transmission line fault simulation device based on PSS / E also includes:

[0038] A third calculation unit is used to obtain a DC voltage, active power and / or reactive power in the DC transmission line according to the current value in the DC transmission line.

[0039] Further, the acquisition module includes: a first judgment unit and a second judgment unit, the first calculation module includes: a first calculation unit and a second calculation unit, and the second calculation module includes: a third calculation unit and a fourth calculation unit;

[0040] The first judgment unit is used to judge whether a ground fault occurs at the head end of the DC transmission line;

[0041] The second judgment unit is used to judge whether the DC current transmission direction is from the rectifier station to the inverter station;

[0042] The first calculation unit is used to calculate the time derivatives of the current in the smoothing reactor and the DC transmission line reactance when a ground fault occurs at the head end of the DC transmission line and the DC current transmission direction is from the rectifier station to the inverter station, which are respectively:

[0043]

[0044]

[0045] The second calculation unit is used to calculate the time derivatives of the current in the smoothing reactor and the DC transmission line reactance when a ground fault occurs at the head end of the DC transmission line and the DC current transmission direction is not from the rectifier station to the inverter station, which are respectively:

[0046]

[0047]

[0048] The third calculation unit is used to calculate the time derivatives of the current in the smoothing reactor when no ground fault occurs at the head end of the DC transmission line and the DC current transmission direction is from the rectifier station to the inverter station:

[0049]

[0050] The fourth calculation unit is used for, when no ground fault occurs at the head end of the DC transmission line and the DC current transmission direction is not from the rectifier station to the inverter station, the derivatives of the current in the smoothing reactor with respect to time are respectively:

[0051]

[0052] Among them, i LS_R is the current close to the smoothing reactor on the rectifier side, u DC_R is the DC voltage on the rectifier side, R RS_R is the resistance of the smoothing reactor, L LC_R is the commutation reactance on the rectifier side, L LS_R is the reactance of the smoothing reactor, i L_R is the current flowing through the DC line, u C_C is the DC line to ground branch capacitance voltage, i C_C is the current flowing through the DC line to the ground branch, R R_C is the DC line to ground branch resistance, R R_R is the DC line resistance, L L_R is the DC line reactance.

[0053] Furthermore, when a ground fault occurs at the head end of the DC transmission line, the first calculation module calculates the current value of the smoothing reactor and the current value in the DC transmission line reactor as follows:

[0054]

[0055]

[0056] When there is no ground fault at the head end of the DC transmission line, the current value of the smoothing reactor of the second calculation module is:

[0057]

[0058] Accordingly, a third aspect of an embodiment of the present invention provides an electronic device, comprising: at least one processor; and a memory connected to the at least one processor; wherein the memory stores instructions executable by the one processor, and the instructions are executed by the one processor so that the at least one processor executes the above-mentioned PSS / E-based DC transmission line fault simulation method.

[0059] Accordingly, a fourth aspect of an embodiment of the present invention provides a computer-readable storage medium having computer instructions stored thereon, which, when executed by a processor, implement the above-mentioned PSS / E-based DC transmission line fault simulation method.

[0060] The above technical solution of the embodiment of the present invention has the following beneficial technical effects:

[0061] By building a T-type equivalent circuit in the DC transmission line and selecting the faulty branch, the current of each branch is calculated according to the loop formed by each branch in the T-type equivalent circuit and the selected faulty branch. The calculation of DC current and DC voltage in the DC transmission system after the DC transmission line fault can be accurately simulated, which provides technical support for system research and stable operation, realizes the coordination of the restart logic of the DC transmission control and protection system and the safe and stable control system, and ensures the safe and stable operation of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 is a flow chart of a DC transmission line fault simulation method based on PSS / E provided in an embodiment of the present invention;

[0063] Figure 2 is a schematic diagram of a T-type equivalent circuit provided by an embodiment of the present invention;

[0064] Figure 3 It is a logic diagram of a DC transmission line fault simulation method based on PSS / E provided in an embodiment of the present invention;

[0065] Figure 4 It is a module diagram of a DC power transmission line fault simulation device based on PSS / E provided in an embodiment of the present invention;

[0066] Figure 5 is a schematic diagram of a selection and judgment module provided by an embodiment of the present invention;

[0067] Figure 6 is a schematic diagram of a first computing module provided in an embodiment of the present invention;

[0068] Figure 7 It is a schematic diagram of a second computing module provided in an embodiment of the present invention.

[0069] Reference numerals:

[0070] 1. Model building module, 2. Selection and judgment module, 21. First judgment unit, 22. Second judgment unit, 3. First calculation module, 31. First calculation unit, 32. Second calculation unit, 4. Second calculation module, 41. Third calculation unit, 42. Fourth calculation unit, 5. Third calculation module. DETAILED DESCRIPTION

[0071] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0072] Figure 1 It is a flow chart of a DC transmission line fault simulation method based on PSS / E provided in an embodiment of the present invention.

[0073] Figure 2 It is a schematic diagram of a T-type equivalent circuit provided by an embodiment of the present invention.

[0074] Please refer to Figure 1 and Figure 2 According to a first aspect of an embodiment of the present invention, a method for simulating a DC transmission line fault based on PSS / E is provided, comprising the following steps:

[0075] S100, build a T-type equivalent circuit model of DC transmission line in PSS / E.

[0076] S200, selecting a faulty branch and determining whether the faulty branch is enabled.

[0077] S300, if the fault branch is enabled, the time derivative of the current in the smoothing reactor and the DC transmission line reactor is obtained according to the loop formed by the fault branch and the T-type equivalent circuit and the pre-selected positive direction of the current to obtain the current value in the DC transmission line.

[0078] S400: If the fault branch is not enabled, the time derivative of the current in the smoothing reactor is calculated according to the T-type equivalent circuit and the pre-selected positive direction of the current to obtain the current value in the DC transmission line.

[0079] The current and the time derivative of the current in the reactance of the DC transmission line are the same as the current and the time derivative of the current in the smoothing reactor.

[0080] Furthermore, the PSS / E-based DC transmission line fault simulation method further includes: obtaining a DC voltage, active power and / or reactive power in the DC transmission line according to a current value in the DC transmission line.

[0081] Figure 3 It is a logic diagram of a DC transmission line fault simulation method based on PSS / E provided in an embodiment of the present invention.

[0082] For details, please refer to Figure 3 , judging whether the fault branch is enabled, including: judging whether a ground fault occurs at the head end of the DC transmission line and whether the DC current transmission direction is from the rectifier station to the inverter station.

[0083] When a ground fault occurs at the head end of a DC transmission line and the DC current is transmitted from the rectifier station to the inverter station, the time derivatives of the current in the smoothing reactor and the DC transmission line reactor are:

[0084]

[0085]

[0086] When a ground fault occurs at the head end of a DC transmission line and the DC current transmission direction is not from the rectifier station to the inverter station, the time derivatives of the current in the smoothing reactor and the DC transmission line reactor are:

[0087]

[0088]

[0089] When there is no ground fault at the head end of the DC transmission line and the DC current transmission direction is from the rectifier station to the inverter station, the time derivatives of the current in the smoothing reactor are:

[0090]

[0091] When there is no ground fault at the head end of the DC transmission line and the DC current transmission direction is not from the rectifier station to the inverter station, the time derivatives of the current in the smoothing reactor are:

[0092]

[0093] Among them, i LS_R is the current close to the smoothing reactor on the rectifier side, u DC_R is the DC voltage on the rectifier side, R RS_R is the resistance of the smoothing reactor, L LC_R is the commutation reactance on the rectifier side, L LS_R is the reactance of the smoothing reactor, i L_R is the current flowing through the DC line, u C_C is the DC line to ground branch capacitance voltage, i C_C is the current flowing through the DC line to the ground branch, R R_C is the DC line to ground branch resistance, RR_R is the DC line resistance, L L_R is the DC line reactance.

[0094] Furthermore, when a ground fault occurs at the head end of the DC transmission line, the current value of the smoothing reactor and the current value in the DC transmission line reactor are respectively:

[0095]

[0096]

[0097] When there is no ground fault at the head end of the DC transmission line, the current value of the smoothing reactor is:

[0098]

[0099] Compared with the simulation method of the DC fault restart function in the existing PSS / E model, the embodiment of the present invention discloses a DC transmission line fault simulation method based on PSS / E, a T-type equivalent circuit of the DC transmission line is built in PSS / E, the fault branch is determined by selecting the fault position of the DC transmission line, and the current of each branch is calculated according to the loop formed by each branch in the T-type equivalent circuit and the selected fault branch, and then other electrical quantities of each node after the fault are calculated. Before applying the DC line fault, the current of each branch is calculated according to the three branches of the T-type equivalent circuit. After applying the DC line fault, the current of each branch is calculated according to the loop formed by the fault branch and the T-type equivalent circuit branch. After obtaining the current of each branch, the voltage and power of each node and other quantities are calculated. The present invention is not limited to use in PSS / E, and other electromechanical transient simulation software that can customize the model is also applicable. The above detection method can accurately simulate the calculation of DC current and DC voltage after the DC line fault in electromechanical transient simulation, providing technical tools for system research and stable calculation.

[0100] Figure 4 It is a module diagram of a PSS / E-based DC transmission line fault simulation device provided in an embodiment of the present invention.

[0101] Accordingly, please refer to Figure 4 According to a second aspect of an embodiment of the present invention, a DC transmission line fault simulation device based on PSS / E is provided, comprising:

[0102] Model building module 1, which is used to build a T-type equivalent circuit model of a DC transmission line in PSS / E;

[0103] A selection and judgment module 2 is used to select a fault branch and judge whether the fault branch is enabled;

[0104] A first calculation module 3 is used to obtain the time derivative of the current in the smoothing reactor and the DC transmission line reactance according to the loop formed by the fault branch and the T-type equivalent circuit and the pre-selected positive direction of the current when the fault branch is enabled, so as to obtain the current value in the DC transmission line;

[0105] A second calculation module 4 is used to calculate the time derivative of the current in the smoothing reactor according to the T-type equivalent circuit and the pre-selected positive direction of the current when the fault branch is not enabled, so as to obtain the current value in the DC transmission line;

[0106] The current and the time derivative of the current in the reactance of the DC transmission line are the same as the current and the time derivative of the current in the smoothing reactor.

[0107] Furthermore, the DC transmission line fault simulation device based on PSS / E also includes: a third calculation unit 5, which is used to obtain the DC voltage, active power and / or reactive power in the DC transmission line according to the current value in the DC transmission line.

[0108] Figure 5 It is a schematic diagram of a selection and judgment module provided in an embodiment of the present invention.

[0109] Figure 6 It is a schematic diagram of a first computing module provided in an embodiment of the present invention.

[0110] Figure 7 It is a schematic diagram of a second computing module provided in an embodiment of the present invention.

[0111] For details, please refer to Figure 5 , Figure 6 and Figure 7 The acquisition judgment module 2 includes: a first judgment unit 21 and a second judgment unit 22 , the first calculation module includes 3: a first calculation unit 31 and a second calculation unit 32 , and the second calculation module includes 4: a third calculation unit 41 and a fourth calculation unit 42 .

[0112] The first judgment unit 21 is used to judge whether a ground fault occurs at the head end of the DC transmission line; the second judgment unit 22 is used to judge whether the DC current transmission direction is from the rectifier station to the inverter station.

[0113] The first calculation unit 31 is used to calculate the time derivatives of the current in the smoothing reactor and the DC transmission line reactor when a ground fault occurs at the head end of the DC transmission line and the DC current transmission direction is from the rectifier station to the inverter station, which are respectively:

[0114]

[0115]

[0116] The second calculation unit 32 is used to calculate the time derivatives of the current in the smoothing reactor and the DC transmission line reactor when a ground fault occurs at the head end of the DC transmission line and the DC current transmission direction is not from the rectifier station to the inverter station, which are respectively:

[0117]

[0118]

[0119] The third calculation unit 41 is used to calculate the time derivative of the current in the smoothing reactor when there is no ground fault at the head end of the DC transmission line and the DC current transmission direction is from the rectifier station to the inverter station:

[0120]

[0121] The fourth calculation unit 42 is used for, when there is no ground fault at the head end of the DC transmission line and the DC current transmission direction is not from the rectifier station to the inverter station, the derivatives of the current in the smoothing reactor with respect to time are:

[0122]

[0123] Among them, i LS_R is the current close to the smoothing reactor on the rectifier side, u DC_R is the DC voltage on the rectifier side, R RS_R is the resistance of the smoothing reactor, L LC_R is the commutation reactance on the rectifier side, L LS_R is the reactance of the smoothing reactor, i L_R is the current flowing through the DC line, u C_C is the DC line to ground branch capacitance voltage, i C_C is the current flowing through the DC line to the ground branch, R R_C is the DC line to ground branch resistance, R R_R is the DC line resistance, L L_R is the DC line reactance.

[0124] Furthermore, when a ground fault occurs at the head end of the DC transmission line, the first calculation module 3 calculates the current value of the smoothing reactor and the current value in the DC transmission line reactor as follows:

[0125]

[0126]

[0127] Second calculation module 4 When there is no ground fault at the head end of the DC transmission line, the current value of the smoothing reactor is:

[0128]

[0129] Accordingly, a third aspect of an embodiment of the present invention provides an electronic device, comprising: at least one processor; and a memory connected to the at least one processor; wherein the memory stores instructions that can be executed by a processor, and the instructions are executed by a processor so that the at least one processor executes the above-mentioned PSS / E-based DC transmission line fault simulation method.

[0130] Accordingly, a fourth aspect of an embodiment of the present invention provides a computer-readable storage medium having computer instructions stored thereon, which, when executed by a processor, implement the above-mentioned PSS / E-based DC transmission line fault simulation method.

[0131] The embodiment of the present invention aims to protect a method and device for simulating faults of a DC transmission line based on PSS / E, wherein the method comprises the following steps: constructing a T-type equivalent circuit model of a DC transmission line in PSS / E; selecting a fault branch and determining whether the fault branch is enabled; if the fault branch is enabled, obtaining the time derivative of the current in the smoothing reactor and the DC transmission line reactance according to the loop formed by the fault branch and the T-type equivalent circuit and the pre-selected positive direction of the current, so as to obtain the current value in the DC transmission line; if the fault branch is not enabled, calculating the time derivative of the current in the smoothing reactor according to the T-type equivalent circuit and the pre-selected positive direction of the current, so as to obtain the current value in the DC transmission line; wherein the current in the reactance of the DC transmission line and the time derivative of the current are the same as the current and the time derivative of the current in the smoothing reactor. The above technical scheme has the following effects:

[0132] By building a T-type equivalent circuit in the DC transmission line and selecting the faulty branch, the current of each branch is calculated according to the loop formed by each branch in the T-type equivalent circuit and the selected faulty branch. The calculation of DC current and DC voltage in the DC transmission system after the DC transmission line fault can be accurately simulated, which provides technical support for system research and stable operation, realizes the coordination of the restart logic of the DC transmission control and protection system and the safe and stable control system, and ensures the safe and stable operation of the power system.

[0133] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and do not constitute a limitation of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the appended claims, or the equivalent forms of such scope and boundaries.

Claims

1. A DC transmission line fault simulation method based on PSS / E, characterized in that: The steps include: Build a T-type equivalent circuit model of a DC transmission line in PSS / E; Selecting a faulty branch and determining whether the faulty branch is enabled; If the fault branch is enabled, the time derivative of the current in the smoothing reactor and the DC transmission line reactance is obtained according to the loop formed by the fault branch and the T-type equivalent circuit and the pre-selected positive direction of the current, so as to obtain the current value in the DC transmission line; If the fault branch is not enabled, the derivative of the current in the smoothing reactor with respect to time is calculated according to the T-type equivalent circuit and the pre-selected positive direction of the current to obtain the current value in the DC transmission line; The current and the time derivative of the current in the reactance of the DC transmission line are the same as the current and the time derivative of the current in the smoothing reactor.

2. The method for simulating a DC power transmission line fault based on PSS / E according to claim 1, characterized in that: Also includes: According to the current value in the DC transmission line, a DC voltage, active power and / or reactive power in the DC transmission line is obtained.

3. The method for simulating DC transmission line faults based on PSS / E according to claim 1, characterized in that: The determining whether the fault branch is enabled includes: Determine whether a ground fault occurs at the head end of the DC transmission line and whether the DC current transmission direction is from the rectifier station to the inverter station; When a ground fault occurs at the head end of the DC transmission line and the DC current transmission direction is from the rectifier station to the inverter station, the time derivatives of the current in the smoothing reactor and the DC transmission line reactor are respectively: When a ground fault occurs at the head end of the DC transmission line and the DC current transmission direction is not from the rectifier station to the inverter station, the time derivatives of the current in the smoothing reactor and the DC transmission line reactor are respectively: When there is no ground fault at the head end of the DC transmission line and the DC current is transmitted from the rectifier station to the inverter station, the derivatives of the current in the smoothing reactor with respect to time are respectively: When no ground fault occurs at the head end of the DC transmission line and the DC current transmission direction is not from the rectifier station to the inverter station, the time derivatives of the current in the smoothing reactor are respectively: Among them, i LS_R is the current close to the smoothing reactor on the rectifier side, u DC_R is the DC voltage on the rectifier side, R RS_R is the resistance of the smoothing reactor, L LC_R is the commutation reactance on the rectifier side, L LS_R is the reactance of the smoothing reactor, i L_R is the current flowing through the DC line, u C_C is the DC line to ground branch capacitance voltage, i C_C is the current flowing through the DC line to the ground branch, R R_C is the DC line to ground branch resistance, R R_R is the DC line resistance, L L_R is the DC line reactance.

4. The method for simulating DC transmission line faults based on PSS / E according to claim 3, characterized in that: When a ground fault occurs at the head end of the DC transmission line, the current value of the smoothing reactor and the current value in the DC transmission line reactor are respectively: When there is no ground fault at the head end of the DC transmission line, the current value of the smoothing reactor is:

5. A DC transmission line fault simulation device based on PSS / E, characterized in that: include: Model building module, which is used to build a T-type equivalent circuit model of a DC transmission line in PSS / E; A selection and judgment module is used to select a fault branch and judge whether the fault branch is enabled; A first calculation module, which is used to obtain the time derivative of the current in the smoothing reactor and the DC transmission line reactance according to the loop formed by the fault branch and the T-type equivalent circuit and the pre-selected positive direction of the current when the fault branch is enabled, so as to obtain the current value in the DC transmission line; A second calculation module, which is used to calculate the derivative of the current in the smoothing reactor with respect to time according to the T-type equivalent circuit and the pre-selected positive direction of the current when the fault branch is not enabled, so as to obtain the current value in the DC transmission line; The current and the time derivative of the current in the reactance of the DC transmission line are the same as the current and the time derivative of the current in the smoothing reactor.

6. The PSS / E-based DC transmission line fault simulation device according to claim 5, characterized in that: Also includes: A third calculation unit is used to obtain a DC voltage, active power and / or reactive power in the DC transmission line according to the current value in the DC transmission line.

7. The PSS / E-based DC transmission line fault simulation device according to claim 5, characterized in that: The selection and judgment module includes: a first judgment unit and a second judgment unit, the first calculation module includes: a first calculation unit and a second calculation unit, and the second calculation module includes: a third calculation unit and a fourth calculation unit; The first judgment unit is used to judge whether a ground fault occurs at the head end of the DC transmission line; The second judgment unit is used to judge whether the DC current transmission direction is from the rectifier station to the inverter station; The first calculation unit is used to calculate the time derivatives of the current in the smoothing reactor and the DC transmission line reactance when a ground fault occurs at the head end of the DC transmission line and the DC current transmission direction is from the rectifier station to the inverter station, which are respectively: The second calculation unit is used to calculate the time derivatives of the current in the smoothing reactor and the DC transmission line reactance when a ground fault occurs at the head end of the DC transmission line and the DC current transmission direction is not from the rectifier station to the inverter station, which are respectively: The third calculation unit is used to calculate the time derivatives of the current in the smoothing reactor when no ground fault occurs at the head end of the DC transmission line and the DC current transmission direction is from the rectifier station to the inverter station: The fourth calculation unit is used for, when no ground fault occurs at the head end of the DC transmission line and the DC current transmission direction is not from the rectifier station to the inverter station, the derivatives of the current in the smoothing reactor with respect to time are respectively: Among them, i LS_R is the current close to the smoothing reactor on the rectifier side, u DC_R is the DC voltage on the rectifier side, R RS_R is the resistance of the smoothing reactor, L LC_R is the commutation reactance on the rectifier side, L LS_R is the reactance of the smoothing reactor, i L_R is the current flowing through the DC line, u C_C is the DC line to ground branch capacitance voltage, i C_C is the current flowing through the DC line to the ground branch, R R_C is the DC line to ground branch resistance, R R_R is the DC line resistance, L L_R is the DC line reactance.

8. The PSS / E-based DC transmission line fault simulation device according to claim 7, characterized in that: When a ground fault occurs at the head end of the DC transmission line, the first calculation module calculates the current value of the smoothing reactor and the current value in the DC transmission line reactor to be: When no ground fault occurs at the head end of the DC transmission line, the current value of the smoothing reactor of the second calculation module is:

9. An electronic device, characterized in that: include: at least one processor; and a memory connected to the at least one processor; wherein the memory stores instructions executable by the one processor, and the instructions are executed by the one processor so that the at least one processor executes the above-mentioned PSS / E-based DC transmission line fault simulation method.

10. A computer-readable storage medium, characterized in that: Computer instructions are stored thereon, and when the instructions are executed by the processor, the above-mentioned PSS / E-based DC transmission line fault simulation method is implemented.

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