Method for determining voltage control and line resistance clipping range of direct current transmission system

Abstract

This application relates to a method and apparatus for determining the limiting range of line resistance in a DC transmission system, a voltage control method and apparatus for a DC transmission system, computer equipment, storage medium, and computer program product. The method includes: measuring and obtaining the line temperature and corresponding line resistance value of the DC transmission line; calculating and determining the maximum and minimum resistance values ​​of the line as the line temperature changes based on the line temperature and line resistance value; and determining the limiting range of the line resistance based on the maximum and minimum resistance values. Using this method can improve the stability of the DC transmission system.

Description

Technical Field

[0001] This application relates to the field of power technology, and in particular to a method and apparatus for determining the limiting range of line resistance in a DC transmission system, a voltage control method and apparatus for a DC transmission system, computer equipment, storage media, and computer program products. Background Technology

[0002] DC transmission systems are an important means of achieving long-distance cross-regional energy exchange, optimizing resource allocation, and transmitting clean energy. Currently, the steady state of DC transmission systems can be achieved by indirectly controlling the DC voltage of the inverter station to influence the DC voltage of the rectifier station.

[0003] However, during the steady-state control of a DC system, DC voltage control disorder may occur, which leads to low stability of the DC transmission system. Summary of the Invention

[0004] Based on this, it is necessary to provide a method and apparatus for determining the limiting range of line resistance of a DC transmission system, a voltage control method and apparatus for a DC transmission system, a computer device, a storage medium, and a computer program product that can improve the stability of a DC transmission system, in response to the above-mentioned technical problems.

[0005] In a first aspect, this application provides a method for determining the limiting range of the line resistance of a DC transmission system, the method comprising:

[0006] The line temperature and corresponding line resistance value of the DC transmission line are measured.

[0007] Based on the line temperature and the line resistance value, calculate and determine the maximum and minimum resistance values ​​of the line as the line temperature changes.

[0008] Based on the maximum resistance value and the minimum resistance value, the limiting range of the line resistance is determined.

[0009] In one embodiment, determining the limiting range of the line resistance based on the maximum resistance value and the minimum resistance value includes:

[0010] Determine the maximum line resistance error caused by voltage measurement error and current measurement error;

[0011] The limiting range of the line resistance is determined based on the maximum resistance value, the minimum resistance value, and the maximum line resistance error value.

[0012] In one embodiment, determining the maximum line resistance error value caused by voltage measurement error and current measurement error includes:

[0013] Based on the maximum voltage measurement error of the DC transmission line, the maximum voltage measurement deviation of the DC transmission line is determined, wherein the voltage measurement error includes the maximum voltage measurement error;

[0014] Based on the maximum measurement deviation of the line voltage, the minimum value of the DC line current, and the maximum current measurement error, the maximum line resistance error caused by the measurement error is determined, wherein the current measurement error includes the maximum current measurement error.

[0015] In one embodiment, the maximum measurement deviation of the line voltage is the product of the maximum voltage measurement error of the DC transmission line and the rated voltage of the DC transmission line.

[0016] In one embodiment, the maximum line resistance error value is twice the product of the sum of the maximum current measurement error and 1, and the ratio of the maximum line voltage measurement deviation to the minimum DC line current.

[0017] In one embodiment, determining the limiting range of the line resistance based on the maximum resistance value, the minimum resistance value, and the maximum line resistance error value includes:

[0018] If the minimum resistance value is greater than the maximum line resistance error value, the difference between the minimum resistance value and the maximum line resistance error value is determined as the lower limit of the limiting range, and the sum of the maximum resistance value and the maximum line resistance error value is determined as the upper limit of the limiting range.

[0019] In one embodiment, determining the limiting range of the line resistance based on the maximum resistance value, the minimum resistance value, and the maximum line resistance error value includes:

[0020] If the minimum resistance value is less than or equal to the maximum line resistance error value, the sum of the maximum resistance value and the maximum line resistance error value is determined as the upper limit of the limiting range, and the lower limit of the limiting range is set to 0.

[0021] In one embodiment, calculating and determining the maximum and minimum resistance values ​​of the line as a function of the line temperature, based on the line temperature and the line resistance value, includes:

[0022] The maximum resistance value is determined based on the line resistance value, the line temperature, the upper limit of the line temperature, and the line resistance temperature rise coefficient.

[0023] The minimum resistance value is determined based on the line resistance value, the line temperature, the lower limit of the line temperature, and the line resistance temperature rise coefficient.

[0024] In one embodiment, determining the maximum resistance value based on the line resistance value, the line temperature, the upper limit of the line temperature, and the line resistance temperature rise coefficient includes:

[0025] The maximum resistance value is the ratio of the sum of the line resistance value and the first parameter, where the first parameter is the sum of 1 and a first product, and the first product is the product of the difference between the line temperature and the upper limit of the line temperature and the temperature rise coefficient of the line resistance.

[0026] In one embodiment, determining the minimum resistance value based on the line resistance value, the line temperature, the lower limit of the line temperature, and the line resistance temperature rise coefficient includes:

[0027] The minimum resistance value is the ratio of the sum of the line resistance value and the second parameter, where the second parameter is the sum of 1 and a second product, and the second product is the product of the difference between the line temperature and the lower limit of the line temperature and the line resistance temperature rise coefficient.

[0028] Secondly, this application provides a device for determining the limiting range of line resistance in a DC transmission system. The device includes a measurement module, a calculation module, and a determination module.

[0029] The measurement module is used to measure and obtain the line temperature and corresponding line resistance value of the DC transmission line.

[0030] The calculation module is used to calculate and determine the maximum and minimum resistance values ​​of the line as the line temperature changes, based on the line temperature and the line resistance value.

[0031] The determining module is used to determine the limiting range of the line resistance based on the maximum resistance value and the minimum resistance value.

[0032] Thirdly, this application also provides a computer device. The computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to perform the following steps:

[0033] The line temperature and corresponding line resistance value of the DC transmission line are measured.

[0034] Based on the line temperature and the line resistance value, calculate and determine the maximum and minimum resistance values ​​of the line as the line temperature changes.

[0035] Based on the maximum resistance value and the minimum resistance value, the limiting range of the line resistance is determined.

[0036] Fourthly, this application also provides a computer-readable storage medium. The computer-readable storage medium stores a computer program thereon, which, when executed by a processor, performs the following steps:

[0037] The line temperature and corresponding line resistance value of the DC transmission line are measured.

[0038] Based on the line temperature and the line resistance value, calculate and determine the maximum and minimum resistance values ​​of the line as the line temperature changes.

[0039] Based on the maximum resistance value and the minimum resistance value, the limiting range of the line resistance is determined.

[0040] Fifthly, this application also provides a computer program product. The computer program product includes a computer program that, when executed by a processor, performs the following steps:

[0041] The line temperature and corresponding line resistance value of the DC transmission line are measured.

[0042] Based on the line temperature and the line resistance value, calculate and determine the maximum and minimum resistance values ​​of the line as the line temperature changes.

[0043] Based on the maximum resistance value and the minimum resistance value, the limiting range of the line resistance is determined.

[0044] The aforementioned method, apparatus, computer equipment, storage medium, and computer program product for determining the limiting range of line resistance in a DC transmission system acquires and measures the line temperature and corresponding line resistance value of the DC transmission line. Based on the line temperature and line resistance value, it calculates and determines the maximum and minimum resistance values ​​as the line temperature changes, and then determines the limiting range of the line resistance based on these maximum and minimum resistance values. Thus, by considering the DC transmission line temperature and determining the limiting range of the line resistance based on the maximum and minimum resistance values ​​as the line temperature changes, the controllability in the event of DC voltage control disturbances can be improved, thereby enhancing the stability of the DC transmission system.

[0045] Sixthly, this application provides a voltage control method for a DC transmission system, the method comprising:

[0046] The line temperature of the DC transmission line, as well as the corresponding line resistance and DC current value, are measured and obtained.

[0047] Based on the line temperature and the line resistance value, calculate and determine the maximum and minimum resistance values ​​of the line as the line temperature changes.

[0048] Based on the maximum resistance value and the minimum resistance value, the limiting range of the line resistance is determined;

[0049] The line voltage drop of the DC transmission line is determined based on the limiting range of the line resistance and the DC current value.

[0050] Based on the line voltage drop and the inverter station's constant DC voltage, the rated value of the rectifier station's DC voltage is controlled.

[0051] In a seventh aspect, this application provides a voltage control device for a DC transmission system. The device includes a limit range determination device for the line resistance of the DC transmission system, a processing module, and a control module. The limit range determination device for the line resistance of the DC transmission system includes a measurement module, a calculation module, and a determination module.

[0052] The measurement module is used to measure and obtain the line temperature of the DC transmission line and the corresponding line resistance value and DC current value.

[0053] The calculation module is used to calculate and determine the maximum and minimum resistance values ​​of the line as the line temperature changes, based on the line temperature and the line resistance value.

[0054] The determining module is used to determine the limiting range of the line resistance based on the maximum resistance value and the minimum resistance value;

[0055] The processing module is used to determine the line voltage drop of the DC transmission line based on the limiting range of the line resistance and the DC current value.

[0056] The control module is used to control the rated value of the DC voltage of the rectifier station based on the line voltage drop and the DC voltage of the inverter station.

[0057] Eighthly, this application also provides a computer device. The computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to perform the following steps:

[0058] The line temperature of the DC transmission line, as well as the corresponding line resistance and DC current value, are measured and obtained.

[0059] Based on the line temperature and the line resistance value, calculate and determine the maximum and minimum resistance values ​​of the line as the line temperature changes.

[0060] Based on the maximum resistance value and the minimum resistance value, the limiting range of the line resistance is determined;

[0061] The line voltage drop of the DC transmission line is determined based on the limiting range of the line resistance and the DC current value.

[0062] Based on the line voltage drop and the inverter station's constant DC voltage, the rated value of the rectifier station's DC voltage is controlled.

[0063] Ninthly, this application also provides a computer-readable storage medium. The computer-readable storage medium stores a computer program thereon, which, when executed by a processor, performs the following steps:

[0064] The line temperature of the DC transmission line, as well as the corresponding line resistance and DC current value, are measured and obtained.

[0065] Based on the line temperature and the line resistance value, calculate and determine the maximum and minimum resistance values ​​of the line as the line temperature changes.

[0066] Based on the maximum resistance value and the minimum resistance value, the limiting range of the line resistance is determined;

[0067] The line voltage drop of the DC transmission line is determined based on the limiting range of the line resistance and the DC current value.

[0068] Based on the line voltage drop and the inverter station's constant DC voltage, the rated value of the rectifier station's DC voltage is controlled.

[0069] Tenthly, this application also provides a computer program product. The computer program product includes a computer program that, when executed by a processor, performs the following steps:

[0070] The line temperature of the DC transmission line, as well as the corresponding line resistance and DC current value, are measured and obtained.

[0071] Based on the line temperature and the line resistance value, calculate and determine the maximum and minimum resistance values ​​of the line as the line temperature changes.

[0072] Based on the maximum resistance value and the minimum resistance value, the limiting range of the line resistance is determined;

[0073] The line voltage drop of the DC transmission line is determined based on the limiting range of the line resistance and the DC current value.

[0074] Based on the line voltage drop and the inverter station's constant DC voltage, the rated value of the rectifier station's DC voltage is controlled.

[0075] The voltage control method, device, computer equipment, storage medium, and computer program product of the aforementioned DC transmission system obtain the line temperature, corresponding line resistance, and DC current value of the DC transmission line by measurement. Based on the line temperature and line resistance value, the maximum and minimum resistance values ​​of the line as a function of the line temperature are calculated and determined. Based on the maximum and minimum resistance values, the limiting range of the line resistance can be determined. Based on the limiting range of the line resistance and the DC current value, the line voltage drop of the DC transmission line can be determined. Furthermore, based on the line voltage drop and the rated DC voltage of the inverter station, the rated DC voltage of the rectifier station can be controlled. In this way, on the one hand, the stability of the DC power of the rectifier station can be ensured, and on the other hand, the stability of the DC voltage of the inverter station can be ensured, thereby improving the stability of the DC transmission system. Attached Figure Description

[0076] Figure 1 This is an application environment diagram of a method for determining the limiting range of line resistance in a DC transmission system, as shown in one embodiment.

[0077] Figure 2 This is a flowchart illustrating a method for determining the limiting range of line resistance in a DC transmission system in one embodiment.

[0078] Figure 3 A flowchart illustrating the process of determining the limiting range of line resistance based on the maximum and minimum resistance values;

[0079] Figure 4 This is a flowchart illustrating a voltage control method for a DC transmission system in one embodiment.

[0080] Figure 5 This is a structural block diagram of a device for determining the limiting range of line resistance in a DC transmission system, as shown in one embodiment.

[0081] Figure 6 This is a structural block diagram of a voltage control device for a DC transmission system in one embodiment;

[0082] Figure 7 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0083] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0084] DC transmission systems are an important means of achieving long-distance, cross-regional energy exchange, optimizing resource allocation, and transmitting clean energy. Typically, a DC transmission system includes a rectifier station and an inverter station. The rectifier station ensures the stability of DC power by controlling the DC current, while the inverter station ensures the stability of DC voltage by controlling the DC voltage. For example, a DC transmission system is a high-voltage DC transmission system.

[0085] Currently, the steady state of a high-voltage direct current (HVDC) transmission system can be achieved by indirectly controlling the DC voltage of the inverter station to influence the DC voltage of the rectifier station. The purpose of controlling the DC voltage of the inverter station is to keep the DC voltage of the rectifier station at its rated value. Since the inverter station cannot directly control the DC voltage of the rectifier station, it can indirectly control the DC voltage of the rectifier station by changing the DC voltage of the inverter station. That is, the DC voltage of the inverter station is set to be equal to the difference between the DC voltage of the rectifier station and the voltage drop of the DC transmission line.

[0086] Typically, the line voltage drop of a DC transmission line is not a fixed value, but is calculated based on the DC voltage of the rectifier station, the DC voltage of the inverter station, and the DC current. The calculation process is as follows: 1) Subtract the DC voltage of the inverter station from the DC voltage of the rectifier station, and then divide by the DC current to obtain the line resistance value; 2) Limit the line resistance value to obtain the output value of the line resistance; 3) Multiply the output value of the line resistance by the DC current to obtain the line voltage drop.

[0087] In the above calculation method, if the line resistance value is not limited, it may lead to DC voltage control disorder. Although the line resistance value is limited to avoid DC voltage control disorder, the influence of the line temperature of the DC transmission line on the limiting range is not taken into account. This may result in the output value of the line resistance not being within a reasonable limiting range, leading to low accuracy of the obtained limiting range and low controllability in the event of DC voltage control disorder, thus resulting in low stability of the high voltage DC transmission system.

[0088] In view of this, the method for determining the limiting range of line resistance in a DC transmission system provided in this application embodiment can be applied to, for example... Figure 1The application environment is illustrated. The high-voltage direct current (HVDC) transmission system 102 includes a rectifier station 104 and an inverter station 106, connected by a DC transmission line 108. The line temperature and corresponding line resistance value of the DC transmission line are obtained through measurement. Based on the line temperature and resistance value, the maximum and minimum resistance values ​​as a function of line temperature are calculated. Based on these maximum and minimum resistance values, a limiting range for the line resistance is determined. Thus, considering the line temperature of the DC transmission line, the limiting range for the line resistance, determined based on the maximum and minimum resistance values ​​as a function of line temperature, can improve controllability in cases of DC voltage control disturbances, thereby enhancing the stability of the DC transmission system.

[0089] In one embodiment, such as Figure 2 As shown, a method for determining the limiting range of line resistance in a DC transmission system is provided, which can be applied to... Figure 1 The following steps are used as an example of the high-voltage direct current transmission system 102:

[0090] S202, measures the line temperature and corresponding line resistance of the DC transmission line.

[0091] Specifically, the line temperature of a DC transmission line can be measured using a temperature measuring instrument or other types of equipment used to measure line temperature, and the line resistance value can be measured using a digital multimeter, clamp meter, or other types of equipment used to measure line resistance value; alternatively, a universal device can be used to measure both the line temperature and the corresponding line resistance value of the DC transmission line. When the length of the DC transmission line is divided into multiple segments, the line temperature can refer to the average temperature of the multiple segments of the DC transmission line.

[0092] S204, based on the line temperature and line resistance value, calculate and determine the maximum and minimum resistance values ​​of the line as the line temperature changes.

[0093] In this embodiment, the maximum resistance value can be determined based on the line resistance value, line temperature, upper limit of line temperature, and line resistance temperature rise coefficient. Specifically, the maximum resistance value is the ratio of the sum of the line resistance value and the first parameter, where the first parameter is the sum of 1 and a first product, and the first product is the product of the difference between the line temperature and the upper limit of line temperature and the line resistance temperature rise coefficient.

[0094] Where the maximum resistance is represented as R max The line resistance value is expressed as R. TL Line temperature is represented as TL, and the upper limit of line temperature is represented as T. maxWhen the line resistance temperature rise coefficient is expressed as β, the first product satisfies the following formula: First product = (TL - T) max If )×β, then

[0095] For example, R TL =3.66Ω, TL=30℃, T max =50℃, β=0.0036(1 / ℃), then

[0096] In this embodiment, the minimum resistance value can be determined based on the line resistance value, line temperature, lower limit of line temperature, and line resistance temperature rise coefficient. Specifically, the minimum resistance value is the ratio of the sum of the line resistance value and the second parameter, where the second parameter is the sum of 1 and the second product, and the second product is the product of the difference between the line temperature and the lower limit of line temperature and the line resistance temperature rise coefficient.

[0097] Where the minimum resistance value is represented as R min The line resistance value is expressed as R. TL Line temperature is denoted as TL, and the lower limit of line temperature is denoted as T. min When the line resistance temperature rise coefficient is expressed as β, the second product satisfies the following formula: Second product = (TL - T) min If )×β, then

[0098] For example, R TL =3.66Ω, TL=30℃, T max = -20℃, β = 0.0036 (1 / ℃), then

[0099] S206 determines the limiting range of the line resistance based on the maximum and minimum resistance values.

[0100] In this embodiment, after determining the limiting range of the line resistance based on the maximum and minimum resistance values, the controllability of DC voltage control disorder can be improved based on the limiting range of the line resistance.

[0101] It should be noted that the process of determining the limiting range of the line resistance can be a real-time calculation process or a process of repeatedly executing S202 to S206 after a preset time. It can be set according to the actual application scenario and is not limited here.

[0102] In summary, this embodiment acquires the line temperature and corresponding line resistance value of the DC transmission line through measurement. Based on the line temperature and line resistance value, the maximum and minimum resistance values ​​of the line as a function of the line temperature are calculated and determined. Based on these maximum and minimum resistance values, a limiting range for the line resistance is determined. Thus, considering the DC transmission line temperature, the limiting range for the line resistance obtained based on the maximum and minimum resistance values ​​as a function of the line temperature can improve the controllability in the event of DC voltage control disturbances, thereby improving the stability of the DC transmission system.

[0103] It is understandable that DC transmission lines are affected by line temperature, causing the line resistance to change with temperature. Furthermore, assuming the normal measurement errors for both voltage and current in a DC transmission line are 2‰, taking a 5000MW bipolar ±800kV DC project as an example, the calculated error for the line voltage would be ±1.6kV. Further, when the rated rectified voltage of the rectifier station is expressed as U... rec The DC voltage of the inverter station is expressed as U. inv DC current is expressed as I line At that time, according to The resistance calculation error caused by the measurement error can be obtained. It is evident that measurement errors can also affect the calculated resistance of a circuit.

[0104] Furthermore, as the length of DC lines in multi-terminal DC applications is divided into multiple segments, the length of a single DC line segment decreases. This reduces the range of variation of line resistance with line temperature, increases the impact of measurement errors, and may result in unreasonable line resistance limits even under normal measurement error conditions.

[0105] Based on this, in one embodiment, such as Figure 3 The diagram shows a flowchart for determining the limiting range of the line resistance based on the maximum and minimum resistance values. Figure 3 The method shown further defines S206 and may include the following steps:

[0106] S302, determine the maximum line resistance error value caused by voltage measurement error and current measurement error.

[0107] In this embodiment, the voltage measurement error includes the maximum voltage measurement error, and the current measurement error includes the maximum current measurement error. Specifically, determining the maximum line resistance error caused by the voltage measurement error and the current measurement error includes: determining the maximum line voltage measurement deviation of the DC transmission line based on the maximum voltage measurement error of the DC transmission line; and determining the maximum line resistance error caused by the measurement error based on the maximum line voltage measurement deviation, the minimum DC line current, and the maximum current measurement error.

[0108] Among them, the maximum measurement deviation of line voltage is the product of the maximum voltage measurement error of DC transmission line and the rated voltage of DC transmission line; the maximum line resistance error value is twice the product of the sum of the maximum current measurement error and 1, and the ratio of the maximum measurement deviation of line voltage to the minimum value of DC line current.

[0109] Specifically, when the maximum measurement deviation of the line voltage is expressed as U err The maximum error in voltage measurement for DC transmission lines is expressed as M. U The rated voltage of a DC transmission line is expressed as U. N The maximum line resistance error value is expressed as R. err The minimum value of DC line current is expressed as I. N The maximum error in current measurement is expressed as M. I At that time, U err Satisfy the following formula: U err =M U ×U N R err Satisfy the following formula:

[0110] For example, U N =800kV, M U =0.2%, I N =2.5kA, M I =0.2%, then U err =800kV × 0.2% = 1.6kV, then

[0111] S304 determines the limiting range of the line resistance based on the maximum resistance value, the minimum resistance value, and the maximum line resistance error value.

[0112] Specifically, in one implementation, the limiting range of the line resistance is determined based on the maximum resistance value, the minimum resistance value, and the maximum line resistance error value, including: if the minimum resistance value is greater than the maximum line resistance error value, the difference between the minimum resistance value and the maximum line resistance error value is determined as the lower limit of the limiting range, and the sum of the maximum resistance value and the maximum line resistance error value is determined as the upper limit of the limiting range;

[0113] Specifically, in another implementation, the limiting range of the line resistance is determined based on the maximum resistance value, the minimum resistance value, and the maximum line resistance error value, including: if the minimum resistance value is less than or equal to the maximum line resistance error value, the sum of the maximum resistance value and the maximum line resistance error value is determined as the upper limit of the limiting range, and the lower limit of the limiting range is set to 0.

[0114] Where the minimum resistance value is represented as R min The maximum resistance is represented by R. max The maximum line resistance error value is expressed as R. err When, if R min >R err At that time, R min With R err The difference is determined as the lower limit of the amplitude limiting range, and R is set as the lower limit of the amplitude limiting range. max With R err The sum of is determined as the upper limit of the amplitude limit range, that is, if R min >R err When the line resistance is limited, the limiting range can be expressed as [R]. min -R err R max +R err ]; or, if R min ≤R err At that time, R max With R err The sum of is determined as the upper limit of the limiting range, and the lower limit of the limiting range is set to 0. That is, if R min ≤R err When the line resistance is limited, the limiting range can be expressed as [0, R]. max +R err ].

[0115] For example, R max =3.94Ω, R min =3.10Ω, R err = 1.28256Ω, R min >R err Then the limiting range of the line resistance is [1.81744Ω, 5.22256Ω].

[0116] In summary, this embodiment determines the maximum line resistance error caused by voltage and current measurement errors. Then, based on the maximum resistance, the minimum resistance, and the maximum line resistance error, the limiting range of the line resistance can be determined. By considering the impact of line temperature and measurement errors on the calculated line resistance of the DC transmission line, the accurate calculation of the limiting range of the line resistance in the DC transmission system can be achieved. This improves the accuracy of the obtained limiting range, ensures that the line resistance does not exhibit significant abnormalities under normal conditions, maintains the control stability of the DC line voltage, and further enhances the stability of the DC transmission system.

[0117] In conjunction with the above, in one embodiment, such as Figure 4 As shown, a voltage control method for a DC transmission system is provided, which is applied to... Figure 1 Taking the high-voltage direct current transmission system 102 as an example, the method may include the following steps:

[0118] S402 measures and obtains the line temperature of a DC transmission line, as well as the corresponding line resistance and DC current values.

[0119] S404, based on the line temperature and line resistance value, calculates and determines the maximum and minimum resistance values ​​of the line as the line temperature changes.

[0120] S406 determines the limiting range of line resistance based on the maximum and minimum resistance values.

[0121] In this embodiment, the contents of S402 to S406 can be adapted to the description of the contents of S202 to S206, and will not be repeated here.

[0122] S408 determines the line voltage drop of a DC transmission line based on the limiting range of the line resistance and the DC current value.

[0123] Specifically, the output value of the line resistance can be determined within the limiting range of the line resistance, and then the product of the output value of the line resistance and the DC current value can be determined as the line voltage drop of the DC transmission line.

[0124] For example, the line resistance is limited to [1.81744Ω, 5.22256Ω], the DC current is 5kA, and the output value of the line resistance can be any value within this limited range. For example, if the output value of the line resistance is 3Ω, then the line voltage drop of the DC transmission line is 15kV.

[0125] S410 controls the rated DC voltage of the rectifier station based on the line voltage drop and the inverter station's constant DC voltage.

[0126] Specifically, the rated DC voltage of the rectifier station is the sum of the line voltage drop and the inverter station's rated DC voltage. Therefore, based on the line voltage drop and the inverter station's rated DC voltage, the rated DC voltage of the rectifier station can be controlled.

[0127] In summary, this embodiment measures the line temperature, corresponding line resistance, and DC current of the DC transmission line. Based on the line temperature and resistance, the maximum and minimum resistance values ​​as the line temperature changes are calculated. Based on these maximum and minimum resistance values, the limiting range of the line resistance can be determined. Based on the limiting range of the line resistance and the DC current value, the line voltage drop of the DC transmission line can be determined. Furthermore, based on the line voltage drop and the rated DC voltage of the inverter station, the rated DC voltage of the rectifier station can be controlled. This ensures the stability of both the DC power of the rectifier station and the DC voltage of the inverter station, thereby improving the stability of the high-voltage DC transmission system.

[0128] Based on the same inventive concept, this application also provides a device for determining the limiting range of line resistance in a DC transmission system, used to implement the method for determining the limiting range of line resistance in the DC transmission system described above. The solution provided by this device is similar to the solution described in the above method. Therefore, the specific limitations of one or more embodiments of the device for determining the limiting range of line resistance in a DC transmission system provided below can be found in the limitations of the method for determining the limiting range of line resistance in a DC transmission system described above, and will not be repeated here.

[0129] In one embodiment, such as Figure 5 As shown, a device 500 for determining the limiting range of line resistance in a DC transmission system is provided. The device includes: a measurement module 502, a calculation module 504, and a determination module 506, wherein:

[0130] The measurement module is used to measure and obtain the line temperature and corresponding line resistance value of the DC transmission line.

[0131] The calculation module is used to calculate and determine the maximum and minimum resistance values ​​of the line as the line temperature changes, based on the line temperature and the line resistance value.

[0132] The determination module is used to determine the limiting range of the line resistance based on the maximum and minimum resistance values.

[0133] In one embodiment, the determining module is further configured to determine the maximum line resistance error value caused by voltage measurement error and current measurement error; and to determine the limiting range of the line resistance based on the maximum resistance value, the minimum resistance value and the maximum line resistance error value.

[0134] In one embodiment, the determining module is further configured to determine the maximum measurement deviation of the line voltage of the DC transmission line based on the maximum voltage measurement error of the DC transmission line, wherein the voltage measurement error includes the maximum voltage measurement error; and to determine the maximum line resistance error value caused by the measurement error based on the maximum line voltage measurement deviation, the minimum DC line current, and the maximum current measurement error, wherein the current measurement error includes the maximum current measurement error.

[0135] In one embodiment, the maximum measurement deviation of the line voltage is the product of the maximum voltage measurement error of the DC transmission line and the rated voltage of the DC transmission line.

[0136] In one embodiment, the maximum line resistance error value is twice the product of the sum of the maximum current measurement error and 1, and the ratio of the maximum line voltage measurement deviation to the minimum DC line current.

[0137] In one embodiment, the determining module is further configured to, if the minimum resistance value is greater than the maximum line resistance error value, determine the difference between the minimum resistance value and the maximum line resistance error value as the lower limit of the limiting range, and determine the sum of the maximum resistance value and the maximum line resistance error value as the upper limit of the limiting range.

[0138] In one embodiment, the determining module is further configured to, if the minimum resistance value is less than or equal to the maximum line resistance error value, determine the sum of the maximum resistance value and the maximum line resistance error value as the upper limit of the limiting range, and set the lower limit of the limiting range to 0.

[0139] In one embodiment, the calculation module is further configured to determine the maximum resistance value based on the line resistance value, line temperature, upper limit of line temperature, and line resistance temperature rise coefficient; and to determine the minimum resistance value based on the line resistance value, line temperature, lower limit of line temperature, and line resistance temperature rise coefficient.

[0140] In one embodiment, the maximum resistance is the ratio of the sum of the line resistance value and the first parameter, where the first parameter is the sum of 1 and a first product, and the first product is the product of the difference between the line temperature and the upper limit of the line temperature and the line resistance temperature rise coefficient.

[0141] In one embodiment, the minimum resistance value is the ratio of the sum of the line resistance value and the second parameter, which is the sum of 1 and a second product, and the second product is the product of the difference between the line temperature and the lower limit of the line temperature and the line resistance temperature rise coefficient.

[0142] Based on the same inventive concept, this application also provides a voltage control device for a DC transmission system for implementing the voltage control method of the DC transmission system described above. The solution provided by this device is similar to the solution described in the above method. Therefore, the specific limitations in one or more embodiments of the voltage control device for a DC transmission system provided below can be found in the limitations of the voltage control method for the DC transmission system described above, and will not be repeated here.

[0143] In one embodiment, such as Figure 6 As shown, a voltage control device for a DC transmission system is provided, comprising: a limiting range determination device 500 for the line resistance of the DC transmission system, a processing module 602, and a control module 604. The limiting range determination device 500 for the line resistance of the DC transmission system includes: a measurement module 502, a calculation module 504, and a determination module 506, wherein:

[0144] The measurement module 502 is used to measure and obtain the line temperature of the DC transmission line and the corresponding line resistance and DC current value.

[0145] The calculation module 504 is used to calculate and determine the maximum and minimum resistance values ​​of the line as the line temperature changes, based on the line temperature and the line resistance value.

[0146] The determination module 506 is used to determine the limiting range of the line resistance based on the maximum and minimum resistance values.

[0147] The processing module 602 is also used to determine the line voltage drop of the DC transmission line based on the limiting range of the line resistance and the DC current value.

[0148] The control module 604 is used to control the rated value of the DC voltage of the rectifier station based on the line voltage drop and the constant DC voltage of the inverter station.

[0149] The various modules in the aforementioned device for determining the limiting range of line resistance in a DC transmission system or the voltage control device for a DC transmission system can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in hardware or independently of the processor in a computer device, or stored in software in the memory of a computer device, so that the processor can call and execute the corresponding operations of each module.

[0150] In one embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be as follows: Figure 7As shown, the computer device includes a processor, memory, and a network interface connected via a system bus. The processor provides computing and control capabilities. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The network interface is used to communicate with external terminals via a network connection. When executed by the processor, the computer program implements a method for determining the limiting range of the line resistance of a DC transmission system or a voltage control method for a DC transmission system.

[0151] Those skilled in the art will understand that Figure 7 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0152] In one embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to perform the following steps:

[0153] The line temperature and corresponding line resistance value of the DC transmission line are measured.

[0154] Based on the line temperature and line resistance value, calculate and determine the maximum and minimum resistance values ​​of the line as the line temperature changes.

[0155] The limiting range of the line resistance is determined based on the maximum and minimum resistance values.

[0156] In one embodiment, the processor further performs the following steps when executing the computer program:

[0157] Determine the maximum line resistance error caused by voltage measurement error and current measurement error;

[0158] The limiting range of the line resistance is determined based on the maximum resistance value, the minimum resistance value, and the maximum line resistance error value.

[0159] In one embodiment, the processor further performs the following steps when executing the computer program:

[0160] Based on the maximum voltage measurement error of DC transmission lines, the maximum measurement deviation of line voltage of DC transmission lines is determined, and the voltage measurement error includes the maximum voltage measurement error;

[0161] Based on the maximum measurement deviation of the line voltage, the minimum value of the DC line current, and the maximum error of the current measurement, determine the maximum line resistance error caused by the measurement error. The current measurement error includes the maximum error of the current measurement.

[0162] In one embodiment, the processor further performs the following steps when executing the computer program:

[0163] The maximum measurement deviation of line voltage is the product of the maximum voltage measurement error of the DC transmission line and the rated voltage of the DC transmission line.

[0164] In one embodiment, the processor further performs the following steps when executing the computer program:

[0165] The maximum line resistance error is twice the product of the sum of the maximum current measurement error and 1, and the ratio of the maximum line voltage measurement deviation to the minimum DC line current.

[0166] In one embodiment, the processor further performs the following steps when executing the computer program:

[0167] If the minimum resistance value is greater than the maximum line resistance error value, the difference between the minimum resistance value and the maximum line resistance error value is determined as the lower limit of the limiting range, and the sum of the maximum resistance value and the maximum line resistance error value is determined as the upper limit of the limiting range.

[0168] In one embodiment, the processor further performs the following steps when executing the computer program:

[0169] If the minimum resistance value is less than or equal to the maximum line resistance error value, the sum of the maximum resistance value and the maximum line resistance error value is determined as the upper limit of the limiting range, and the lower limit of the limiting range is set to 0.

[0170] In one embodiment, the processor further performs the following steps when executing the computer program:

[0171] The maximum resistance value is determined based on the line resistance value, line temperature, upper limit of line temperature, and line resistance temperature rise coefficient.

[0172] The minimum resistance value is determined based on the line resistance value, line temperature, lower limit of line temperature, and line resistance temperature rise coefficient.

[0173] In one embodiment, the processor further performs the following steps when executing the computer program:

[0174] The maximum resistance is the ratio of the sum of the line resistance value and the first parameter. The first parameter is the sum of 1 and the first product, which is the product of the difference between the line temperature and the upper limit of the line temperature and the line resistance temperature rise coefficient.

[0175] In one embodiment, the processor further performs the following steps when executing the computer program:

[0176] The minimum resistance is the ratio of the sum of the line resistance and the second parameter. The second parameter is the sum of 1 and the second product, which is the product of the difference between the line temperature and the lower limit of the line temperature and the line resistance temperature rise coefficient.

[0177] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, the computer program performing the following steps when executed by a processor:

[0178] The line temperature and corresponding line resistance value of the DC transmission line are measured.

[0179] Based on the line temperature and line resistance value, calculate and determine the maximum and minimum resistance values ​​of the line as the line temperature changes.

[0180] The limiting range of the line resistance is determined based on the maximum and minimum resistance values.

[0181] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0182] Determine the maximum line resistance error caused by voltage measurement error and current measurement error;

[0183] The limiting range of the line resistance is determined based on the maximum resistance value, the minimum resistance value, and the maximum line resistance error value.

[0184] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0185] Based on the maximum voltage measurement error of DC transmission lines, the maximum measurement deviation of line voltage of DC transmission lines is determined, and the voltage measurement error includes the maximum voltage measurement error;

[0186] Based on the maximum measurement deviation of the line voltage, the minimum value of the DC line current, and the maximum error of the current measurement, determine the maximum line resistance error caused by the measurement error. The current measurement error includes the maximum error of the current measurement.

[0187] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0188] The maximum measurement deviation of line voltage is the product of the maximum voltage measurement error of the DC transmission line and the rated voltage of the DC transmission line.

[0189] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0190] The maximum line resistance error is twice the product of the sum of the maximum current measurement error and 1, and the ratio of the maximum line voltage measurement deviation to the minimum DC line current.

[0191] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0192] If the minimum resistance value is greater than the maximum line resistance error value, the difference between the minimum resistance value and the maximum line resistance error value is determined as the lower limit of the limiting range, and the sum of the maximum resistance value and the maximum line resistance error value is determined as the upper limit of the limiting range.

[0193] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0194] If the minimum resistance value is less than or equal to the maximum line resistance error value, the sum of the maximum resistance value and the maximum line resistance error value is determined as the upper limit of the limiting range, and the lower limit of the limiting range is set to 0.

[0195] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0196] The maximum resistance value is determined based on the line resistance value, line temperature, upper limit of line temperature, and line resistance temperature rise coefficient.

[0197] The minimum resistance value is determined based on the line resistance value, line temperature, lower limit of line temperature, and line resistance temperature rise coefficient.

[0198] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0199] The maximum resistance is the ratio of the sum of the line resistance value and the first parameter. The first parameter is the sum of 1 and the first product, which is the product of the difference between the line temperature and the upper limit of the line temperature and the line resistance temperature rise coefficient.

[0200] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0201] The minimum resistance is the ratio of the sum of the line resistance and the second parameter. The second parameter is the sum of 1 and the second product, which is the product of the difference between the line temperature and the lower limit of the line temperature and the line resistance temperature rise coefficient.

[0202] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, performs the following steps:

[0203] The line temperature and corresponding line resistance value of the DC transmission line are measured.

[0204] Based on the line temperature and line resistance value, calculate and determine the maximum and minimum resistance values ​​of the line as the line temperature changes.

[0205] The limiting range of the line resistance is determined based on the maximum and minimum resistance values.

[0206] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0207] Determine the maximum line resistance error caused by voltage measurement error and current measurement error;

[0208] The limiting range of the line resistance is determined based on the maximum resistance value, the minimum resistance value, and the maximum line resistance error value.

[0209] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0210] Based on the maximum voltage measurement error of DC transmission lines, the maximum measurement deviation of line voltage of DC transmission lines is determined, and the voltage measurement error includes the maximum voltage measurement error;

[0211] Based on the maximum measurement deviation of the line voltage, the minimum value of the DC line current, and the maximum error of the current measurement, determine the maximum line resistance error caused by the measurement error. The current measurement error includes the maximum error of the current measurement.

[0212] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0213] The maximum measurement deviation of line voltage is the product of the maximum voltage measurement error of the DC transmission line and the rated voltage of the DC transmission line.

[0214] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0215] The maximum line resistance error is twice the product of the sum of the maximum current measurement error and 1, and the ratio of the maximum line voltage measurement deviation to the minimum DC line current.

[0216] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0217] If the minimum resistance value is greater than the maximum line resistance error value, the difference between the minimum resistance value and the maximum line resistance error value is determined as the lower limit of the limiting range, and the sum of the maximum resistance value and the maximum line resistance error value is determined as the upper limit of the limiting range.

[0218] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0219] If the minimum resistance value is less than or equal to the maximum line resistance error value, the sum of the maximum resistance value and the maximum line resistance error value is determined as the upper limit of the limiting range, and the lower limit of the limiting range is set to 0.

[0220] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0221] The maximum resistance value is determined based on the line resistance value, line temperature, upper limit of line temperature, and line resistance temperature rise coefficient.

[0222] The minimum resistance value is determined based on the line resistance value, line temperature, lower limit of line temperature, and line resistance temperature rise coefficient.

[0223] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0224] The maximum resistance is the ratio of the sum of the line resistance value and the first parameter. The first parameter is the sum of 1 and the first product, which is the product of the difference between the line temperature and the upper limit of the line temperature and the line resistance temperature rise coefficient.

[0225] In one embodiment, when the computer program is executed by a processor, it further performs the following steps:

[0226] The minimum resistance is the ratio of the sum of the line resistance and the second parameter. The second parameter is the sum of 1 and the second product, which is the product of the difference between the line temperature and the lower limit of the line temperature and the line resistance temperature rise coefficient.

[0227] In one embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to perform the following steps:

[0228] The line temperature of the DC transmission line, as well as the corresponding line resistance and DC current value, are measured and obtained.

[0229] Based on the line temperature and line resistance value, calculate and determine the maximum and minimum resistance values ​​of the line as the line temperature changes.

[0230] Determine the limiting range of the line resistance based on the maximum and minimum resistance values;

[0231] Determine the line voltage drop of the DC transmission line based on the limiting range of the line resistance and the DC current value;

[0232] The rated value of the DC voltage of the rectifier station is controlled based on the line voltage drop and the constant DC voltage of the inverter station.

[0233] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, the computer program performing the following steps when executed by a processor:

[0234] The line temperature of the DC transmission line, as well as the corresponding line resistance and DC current value, are measured and obtained.

[0235] Based on the line temperature and line resistance value, calculate and determine the maximum and minimum resistance values ​​of the line as the line temperature changes.

[0236] Determine the limiting range of the line resistance based on the maximum and minimum resistance values;

[0237] Determine the line voltage drop of the DC transmission line based on the limiting range of the line resistance and the DC current value;

[0238] The rated value of the DC voltage of the rectifier station is controlled based on the line voltage drop and the constant DC voltage of the inverter station.

[0239] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, performs the following steps:

[0240] The line temperature of the DC transmission line, as well as the corresponding line resistance and DC current value, are measured and obtained.

[0241] Based on the line temperature and line resistance value, calculate and determine the maximum and minimum resistance values ​​of the line as the line temperature changes.

[0242] Determine the limiting range of the line resistance based on the maximum and minimum resistance values;

[0243] Determine the line voltage drop of the DC transmission line based on the limiting range of the line resistance and the DC current value;

[0244] The rated value of the DC voltage of the rectifier station is controlled based on the line voltage drop and the constant DC voltage of the inverter station.

[0245] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0246] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0247] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for determining the limiting range of line resistance in a DC transmission system, characterized in that, The method includes: The line temperature and corresponding line resistance value of the DC transmission line are measured. Based on the line temperature and the line resistance value, calculate and determine the maximum and minimum resistance values ​​of the line as the line temperature changes. Based on the maximum resistance value and the minimum resistance value, the limiting range of the line resistance is determined; The step of calculating and determining the maximum and minimum resistance values ​​of the line as a function of the line temperature, based on the line temperature and the line resistance value, includes: The maximum resistance is determined based on the line resistance value, the line temperature, the upper limit of the line temperature, and the line resistance temperature rise coefficient; the maximum resistance is the ratio of the sum of the line resistance value and the first parameter, where the first parameter is the sum of 1 and a first product, and the first product is the product of the difference between the line temperature and the upper limit of the line temperature and the line resistance temperature rise coefficient. The minimum resistance value is determined based on the line resistance value, the line temperature, the lower limit of the line temperature, and the line resistance temperature rise coefficient; the minimum resistance value is the ratio of the sum of the line resistance value and the second parameter, the second parameter being the sum of 1 and a second product, the second product being the product of the difference between the line temperature and the lower limit of the line temperature and the line resistance temperature rise coefficient. The step of determining the limiting range of the line resistance based on the maximum resistance value and the minimum resistance value includes: Determine the maximum line resistance error caused by voltage measurement error and current measurement error; The limiting range of the line resistance is determined based on the maximum resistance value, the minimum resistance value, and the maximum line resistance error value.

2. The method according to claim 1, characterized in that, Determining the maximum line resistance error value caused by voltage measurement error and current measurement error includes: Based on the maximum voltage measurement error of the DC transmission line, the maximum voltage measurement deviation of the DC transmission line is determined, wherein the voltage measurement error includes the maximum voltage measurement error; Based on the maximum measurement deviation of the line voltage, the minimum value of the DC line current, and the maximum current measurement error, the maximum line resistance error caused by the measurement error is determined, wherein the current measurement error includes the maximum current measurement error.

3. The method according to claim 2, characterized in that, The maximum measurement deviation of the line voltage is the product of the maximum voltage measurement error of the DC transmission line and the rated voltage of the DC transmission line.

4. The method according to claim 2, characterized in that, The maximum line resistance error value is twice the product of the sum of the maximum current measurement error and 1, and the ratio of the maximum line voltage measurement deviation to the minimum DC line current.

5. The method according to claim 1, characterized in that, Determining the limiting range of the line resistance based on the maximum resistance value, the minimum resistance value, and the maximum line resistance error value includes at least one of the following: First item: If the minimum resistance value is greater than the maximum line resistance error value, the difference between the minimum resistance value and the maximum line resistance error value is determined as the lower limit of the limiting range, and the sum of the maximum resistance value and the maximum line resistance error value is determined as the upper limit of the limiting range. Second item: If the minimum resistance value is less than or equal to the maximum line resistance error value, the sum of the maximum resistance value and the maximum line resistance error value is determined as the upper limit of the limiting range, and the lower limit of the limiting range is set to 0.

6. The method according to claim 1, characterized in that, The method further includes: The line temperature of the DC transmission line is obtained by measuring the temperature with a temperature measuring instrument, and the line resistance value is obtained by measuring the digital multimeter.

7. The method according to claim 1, characterized in that, The DC transmission line comprises multiple sections; the method further includes: The average temperature of multiple line segments is determined as the line temperature of the DC transmission line.

8. A voltage control method for a DC transmission system, characterized in that, The method includes: The line temperature of the DC transmission line, as well as the corresponding line resistance and DC current value, are measured and obtained. Based on the line temperature and the line resistance value, calculate and determine the maximum and minimum resistance values ​​of the line as the line temperature changes. Based on the maximum resistance value and the minimum resistance value, the limiting range of the line resistance is determined; The line voltage drop of the DC transmission line is determined based on the limiting range of the line resistance and the DC current value. Based on the line voltage drop and the inverter station's constant DC voltage, the rated value of the rectifier station's DC voltage is controlled; The step of calculating and determining the maximum and minimum resistance values ​​of the line as a function of the line temperature, based on the line temperature and the line resistance value, includes: The maximum resistance is determined based on the line resistance value, the line temperature, the upper limit of the line temperature, and the line resistance temperature rise coefficient; the maximum resistance is the ratio of the sum of the line resistance value and the first parameter, where the first parameter is the sum of 1 and a first product, and the first product is the product of the difference between the line temperature and the upper limit of the line temperature and the line resistance temperature rise coefficient. The minimum resistance value is determined based on the line resistance value, the line temperature, the lower limit of the line temperature, and the line resistance temperature rise coefficient; the minimum resistance value is the ratio of the sum of the line resistance value and the second parameter, the second parameter being the sum of 1 and a second product, the second product being the product of the difference between the line temperature and the lower limit of the line temperature and the line resistance temperature rise coefficient. The step of determining the limiting range of the line resistance based on the maximum resistance value and the minimum resistance value includes: Determine the maximum line resistance error caused by voltage measurement error and current measurement error; The limiting range of the line resistance is determined based on the maximum resistance value, the minimum resistance value, and the maximum line resistance error value.

9. The method according to claim 8, characterized in that, Determining the line voltage drop of the DC transmission line based on the limiting range of the line resistance and the DC current value includes: The output value of the line resistance is determined from the limiting range of the line resistance; The product of the output value of the line resistance and the value of the DC current is determined as the line voltage drop of the DC transmission line.

10. The method according to claim 8, characterized in that, The rated DC voltage of the rectifier station is the sum of the line voltage drop and the rated DC voltage of the inverter station.

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