24-pulse dc machine set for testing performance of a locomotive and test method

Abstract

The present application belongs to the field of test power supply of traction locomotive, and particularly discloses a 24-pulse DC unit for performance test of traction locomotive, which comprises a self-coupled transformer, a first coil group and a second coil group axially split and arranged in parallel in the self-coupled transformer, a load tap changer electrically connected with the self-coupled transformer, and two parallel rectification branches electrically connected with the load tap changer; the rectification branch comprises a circuit breaker electrically connected with the load tap changer, a rectification transformer electrically connected with the circuit breaker, and a rectifier electrically connected with the rectification transformer; the self-coupled transformer leads into the incoming line end of the 24-pulse DC unit, and the rectifier leads out the outgoing line end of the 24-pulse DC unit. The present application has the characteristics of large capacity, wide voltage regulation range and high line reliability, and overcomes the problems of current limitation of voltage regulator, too many taps of phase-shifting coil and main coil which cannot be arranged in space, and the design is very simple.

Description

Technical Field

[0001] This invention belongs to the field of train test power supply technology, specifically relating to a 24-pulse DC generator set and test method for testing the performance of traction locomotives. Background Technology

[0002] Testing various performance indicators of the traction locomotive through a test circuit is an important means of verifying the locomotive's performance. The following are the requirements for the 24-pulse DC power supply used in traction locomotive performance testing:

[0003] 1. The required apparent (rated) capacity of the traction DC generator set is 6600 kVA;

[0004] 2. The traction rectifier unit needs to adopt a 24-pulse rectification method to effectively suppress harmonics;

[0005] 3. The DC output voltage can be adjusted from 1500V to approximately 1650V to complete the traction condition test in the voltage surge test; the DC output voltage can be adjusted from 1500V to approximately 1350V to complete the electrical condition test in the voltage surge test.

[0006] 4. The DC output voltage can be adjusted from 1000V to 1900V in 112.5V increments to complete voltage fluctuation tests;

[0007] 5. Remote control can be achieved through remote control, remote signaling, remote adjustment, and remote measurement.

[0008] The above requirements for traction DC generator sets mainly reflect the large power, wide voltage adjustment range, and numerous voltage levels required, with each level requiring 24-pulse rectification. Previously used 24-pulse traction rectifier generator sets had a basically fixed rated DC output voltage on the valve side, such as 750V or 1500V, which could not meet the test locomotive's requirements for adjusting the DC output voltage.

[0009] In existing technologies, 24-pulse rectification is typically achieved by combining two rectifier transformers and corresponding rectifiers. Specifically, the high-voltage grid side of the rectifier transformer includes two sets of coils connected in parallel with an extended delta connection, while the low-voltage valve side includes two axially split coils, one delta-connected and the other star-connected, forming a 6-phase 12-pulse rectifier transformer. The rectifier includes two 3-phase 6-pulse full-wave rectifier bridges, each forming an independent 6-pulse rectifier circuit. One rectifier bridge is connected to the valve-side Y-winding of the rectifier transformer, and the other is connected to the valve-side delta-winding. The two rectifier bridges are then connected in parallel to form a 12-pulse rectification. The grid-side windings of the two rectifier transformers are shifted by +7.5° and -7.5° respectively, resulting in a 15° phase angle difference between the valve-side voltages of the two transformers, which, through the rectifier, constitutes an equivalent 24-pulse rectification.

[0010] This DC generator set is only suitable for a small range of voltage regulation, and this voltage regulation is a non-excitation voltage regulation method. That is, when adjusting the tap position, the grid power supply must be cut off. This method is quite different from the actual working conditions of traction locomotive testing and cannot obtain more realistic test results. Summary of the Invention

[0011] This invention provides a 24-pulse DC generator set and test method for testing the performance of traction locomotives, in order to solve the problem that the current test power supply for traction locomotives cannot accurately simulate the test conditions of traction locomotives.

[0012] To solve the above-mentioned technical problems, the technical solution of the present invention is: a 24-pulse DC generator set for traction locomotive performance testing, comprising: an autotransformer, wherein the autotransformer includes a first coil group and a second coil group arranged in parallel with axial splitting; an on-load tap changer electrically connected to the autotransformer; and two parallel rectifier branches, wherein the rectifier branches are electrically connected to the on-load tap changer; each rectifier branch includes a circuit breaker electrically connected to the on-load tap changer, a rectifier transformer electrically connected to the circuit breaker, and a rectifier electrically connected to the rectifier transformer; the autotransformer leads out to the input terminal of the 24-pulse DC generator set, and the rectifier leads out to the output terminal of the 24-pulse DC generator set.

[0013] In a preferred embodiment of the present invention, the first coil group and the second coil group have the same structure; the first coil group is Y-shaped and includes a first phase coil, a second phase coil and a third phase coil with corresponding tap points; the tap points in the first coil group are connected to the corresponding tap points in the second coil group; wherein the tap point connected to the first phase coil leads to a secondary side a contact point, the tap point connected to the second phase coil leads to a secondary side b contact point, and the tap point connected to the third phase coil leads to a secondary side c contact point.

[0014] In a preferred embodiment of the present invention, the on-load tap changer is provided with nine tap stages, and the output voltage difference of the DC unit between two adjacent tap stages is 112.5V.

[0015] In a preferred embodiment of the present invention, the rectifier includes a first rectifier and a second rectifier. The rectifier includes a first output terminal and a second output terminal. The first output terminal of the first rectifier is led out as the positive output terminal of the 24-pulse DC generator. The second output terminal of the first rectifier is connected to the first output terminal of the second rectifier. The second output terminal of the second rectifier is led out as the negative output terminal of the 24-pulse DC generator.

[0016] The present invention also includes a method for testing the performance of a traction locomotive, which uses the 24-pulse DC generator set used for testing the performance of the traction locomotive.

[0017] In a preferred embodiment of the present invention, the following steps are included:

[0018] S1: Determine the target output DC voltage value of the rectifier according to the performance test requirements, and determine the valve-side no-load voltage value of the rectifier transformer from the target output DC voltage value;

[0019] S2: Determine the grid-side input voltage of the rectifier transformer based on the valve-side no-load voltage value of the rectifier transformer;

[0020] S3: Determine the voltage and current values ​​corresponding to each tap on the secondary side of the autotransformer based on the grid-side input voltage value of the rectifier transformer;

[0021] S4: The autotransformer is powered by the primary side rated voltage, and the actual output DC voltage of the rectifier is the target output DC voltage. This is used to perform performance testing on the power supply to the traction locomotive.

[0022] In a preferred embodiment of the present invention, in step S1:

[0023] Obtain the specified no-load DC voltage using equation (1) :

[0024] (1)

[0025] Of this, 6% represents the voltage regulation rate of the rectifier unit. This is the rated voltage of the rectifier unit;

[0026] The 24-pulse ideal no-load DC voltage is obtained by equation (2). :

[0027] (2)

[0028] in, To define the no-load DC voltage;

[0029] The rated no-load voltage on the valve side of the rectifier transformer is obtained by formula (3). With 24 pulses ideal no-load DC voltage Physical relationship:

[0030] (3)

[0031] in, Angular frequency;

[0032] The rated no-load voltage on the valve side of the rectifier transformer is obtained according to equation (4). :

[0033] (4).

[0034] In a preferred embodiment of the present invention, in step S2:

[0035] Referring to formula (5), determine the rated voltage of the grid side and the rated voltage of the valve side of the rectifier transformer according to the actual working conditions. Based on the relationship between the primary and secondary voltages of the transformer and the turns ratio, calculate the voltage required to be input to each tap of the grid side of the rectifier transformer, that is, the voltage value required to be output to each tap of the secondary side of the autotransformer.

[0036] (5)

[0037] in, This refers to the voltage transformation ratio between the grid side and the valve side of the rectifier transformer. This refers to the number of turns in the rated tap winding on the grid side of the rectifier transformer. This refers to the number of turns in the valve-side winding of the rectifier transformer. This is the rated no-load voltage on the grid side of the rectifier transformer. This refers to the rated no-load voltage on the valve side of the rectifier transformer. The voltages required to be output from the valve side of the rectifier transformer. represents the voltage levels that need to be input to the grid side of the rectifier transformer, and n represents the tap level of the on-load tap changer.

[0038] In a preferred embodiment of the present invention, in step S3, the primary side rated current value is obtained according to equation (6). :

[0039] (6)

[0040] in, This refers to the rated capacity of the autotransformer. This is the rated voltage of the primary side of the autotransformer.

[0041] The voltage and current values ​​of each stage on the secondary side of the autotransformer are obtained according to equation (7):

[0042] (7)

[0043] in, This refers to the rated capacity of the autotransformer. These are the voltage values ​​of each stage on the secondary side of the autotransformer. .

[0044] In a preferred embodiment of the present invention, the nine tap stages of the on-load tap changer correspond to the nine output voltages of the DC generator set, from low to high as follows: 1000V / 1112.5V / 1225V / 1337.5V / 1450V / 1562.5V / 1675V / 1787.5V / 1900V; the above voltage values ​​correspond to the 9th to 1st positions of the on-load tap changer, with the 9th position being the lowest position and the 1st position being the highest position.

[0045] In a preferred embodiment of the present invention, when the on-load tap changer is in positions 9, 8, and 7, the capacity of the autotransformer is set to 4400 kVA; when the on-load tap changer is in other positions, the capacity of the autotransformer is set to 6600 kVA.

[0046] In a preferred embodiment of the present invention, the voltage and current values ​​corresponding to the secondary side of the autotransformer at each gear position are calculated through steps S1-S3, and compiled into a table. During testing, the corresponding on-load switch adjustment gear position can be obtained by directly looking up the table based on the target output DC voltage value.

[0047] In a preferred embodiment of the present invention, when conducting a voltage surge test, under simulated traction conditions, the on-load tap changer is adjusted from 4 to 3 based on the target output DC voltage of 1500V to 1650V by referring to a table; under simulated electrical conditions, the on-load tap changer is adjusted from 4 to 6 based on the target output DC voltage of 1500V to 1350V by referring to a table.

[0048] In a preferred embodiment of the present invention, when conducting a voltage fluctuation test, the on-load tap changer is adjusted repeatedly from 1000V to 1900V based on the target output DC voltage value. The tap changer is then adjusted from level 9 to level 1 by referring to a table, and then from level 1 to level 9 again, and this process is repeated 3 times.

[0049] In a preferred embodiment of the present invention, the gear position is adjusted by remote control, remote signaling, remote adjustment or remote measurement of the on-load tap changer.

[0050] The technical solution provided by this invention has the following beneficial effects while retaining the functions of a 24-pulse rectifier unit:

[0051] 1) It features large capacity, wide voltage regulation range, and high line reliability;

[0052] 2) The rectifier unit can achieve synchronous voltage regulation and step voltage regulation, and can realize multiple sudden increases or decreases in voltage.

[0053] 3) It eliminates the problem of current limitation in voltage regulator controllers, and can achieve a wide range of DC voltage regulation from 1000V to 1900V on the valve side of the rectifier unit;

[0054] 4) It can realize on-site manual and remote control online gear adjustment, and on-site and remote control can be controlled separately;

[0055] 5) It overcomes the problem of too many taps in the rectifier transformer's phase-shifting coil and main coil, which cannot be arranged in space, and the rectifier unit design is very simple. Attached Figure Description

[0056] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained from these drawings without creative effort.

[0057] Figure 1 This is a wiring diagram of a 24-pulse DC generator set for traction locomotive performance testing as described in one embodiment of the present invention;

[0058] Figure 2 This is a schematic diagram of the wiring between the autotransformer and the on-load tap changer in a 24-pulse DC generator set used for traction locomotive performance testing, as described in one embodiment of the present invention.

[0059] In the figure: 1 - autotransformer; 2 - on-load tap changer; 3 - circuit breaker; 4 - rectifier transformer; 5 - rectifier. Detailed Implementation

[0060] To facilitate understanding, the design method of a 24-pulse traction DC generator set is described below with reference to embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation and positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0061] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0062] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0063] The 24-pulse DC generator set used for traction locomotive performance testing described in this invention has its input terminal connected to an autotransformer feeder cabinet, which supplies power to the generator set. The output terminal of the generator set is connected to the power module of the traction locomotive to supply power to the traction locomotive.

[0064] like Figure 1 As shown, the 24-pulse DC generator set used for traction locomotive performance testing includes an autotransformer 1, an on-load tap changer 2, and two parallel rectifier branches. The rectifier branches include a circuit breaker 3, a rectifier transformer 4, and a rectifier 5.

[0065] The output terminal of the autotransformer 1 is connected to the input terminal of the on-load tap changer 2. Each contact point is divided into two terminals, which can effectively reduce the probability of local overheating and reduce safety hazards.

[0066] Reference Figure 1 and Figure 2 As shown, the on-load tap changer 2 has a total of nine tap stages. The on-load tap changer 2 has two output terminals, each connected to a rectifier branch. The output terminals of the on-load tap changer 2 are connected to the input terminals of the circuit breaker 3, which in turn are connected to the input terminals of the rectifier transformer 4. The output terminals of the rectifier transformer 4 are connected to the input terminals of the rectifier 5. The rectifier 4 includes a first rectifier and a second rectifier. Each rectifier 4 includes a first output terminal and a second output terminal. The first output terminal of the first rectifier is connected to the positive output terminal of the 24-pulse DC generator set. The second output terminal of the first rectifier is connected to the first output terminal of the second rectifier, and the second output terminal of the second rectifier is connected to the negative output terminal of the 24-pulse DC generator set.

[0067] Reference Figure 2 As shown, the autotransformer 1 of this invention has two coil groups, including a first coil group and a second coil group, which are axially split and connected in parallel. This structure effectively reduces the difficulty of single-coil winding and reduces eddy current losses in the conductors. The first coil group and the second coil group have the same structure. Taking the first coil group as an example, the first coil group is Y-shaped and includes a first-phase coil, a second-phase coil, and a third-phase coil with corresponding tap stages. The tap points in the first coil group are connected to the corresponding tap points in the second coil group. The tap point in the first-phase coil leads to the secondary side a contact, the tap point in the second-phase coil leads to the secondary side b contact, and the tap point in the third-phase coil leads to the secondary side c contact.

[0068] In summary, the output terminal of the on-load tap changer 2 is connected to the grid-side input terminals of the two rectifier transformers 4 via disconnecting switches. Therefore, the capacity of each rectifier transformer 4 is 3300kVA. The primary windings of the two rectifier transformers 4, which operate in parallel or in series, are shifted by +7.5° and -7.5° respectively, so that the phase angle difference of the valve-side voltage of the two rectifier transformers 4 is 15°. Through the rectifier 5, an equivalent 24-pulse rectification is formed, which can effectively suppress harmonics on the grid voltage side. The two rectifiers 5 in this invention are connected in series for output.

[0069] The present invention discloses a test method for a 24-pulse DC generator set used for traction locomotive performance testing, which mainly includes the following steps.

[0070] 1. Obtain the agreed no-load DC voltage value based on the rated voltage value of the rectifier unit.

[0071] Since the test power supply input is 6kV, the actual input voltage range is 5.3kV to 6.5kV due to grid voltage fluctuations. Utilizing the multi-stage output capability of the autotransformer, a 9-stage tap is set on the secondary side of the autotransformer. By adjusting the on-load tap changer, different DC voltage output requirements on the rectifier's DC side can be met. The DC voltage output for each stage is calculated based on the DC voltage step size, which is determined to be 112.5V (DC). The DC voltage tap positions are shown in Table 1.

[0072] Table 1 DC tap voltage of each position of the rectifier unit

[0073] The DC voltage is achieved by two rectifier units connected in series. The DC tap voltage of each rectifier unit is shown in Table 2.

[0074] Table 2 DC tap voltage for each rectifier unit

[0075] Obtain the specified no-load DC voltage using equation (1) :

[0076] (1)

[0077] Of this, 6% represents the voltage regulation rate of the rectifier unit. This is the rated voltage of the rectifier unit.

[0078] Next, based on the agreed no-load DC voltage value, obtain the 24-pulse ideal no-load DC voltage value;

[0079] The 24-pulse ideal no-load DC voltage is obtained by equation (2). :

[0080] (2)

[0081] in, The unloaded DC voltage is specified.

[0082] Then, based on the ideal no-load DC voltage value of 24 pulses, obtain the no-load voltage value on the valve side of the rectifier transformer;

[0083] The open-circuit voltage on the valve side of the rectifier transformer is obtained by equation (3). With 24 pulses ideal no-load DC voltage Physical relationship:

[0084] (3)

[0085] in, Angular frequency;

[0086] Therefore, we can obtain equation (4):

[0087] (4)

[0088] The open-circuit voltage on the valve side of the rectifier transformer is obtained according to equation (4). .

[0089] Table 3 is compiled based on the rated voltage of the rectifier unit, the agreed no-load DC voltage value, the ideal no-load DC voltage value of 24 pulses, and the no-load voltage value of the rectifier transformer valve side.

[0090] Table 3 No-load voltage of each rectifier unit

[0091] 2. First, obtain the grid-side input voltage value of the rectifier transformer based on the primary and secondary turns ratio of the transformer.

[0092] Based on actual operating conditions, the rated open-circuit voltage on the valve side of the rectifier transformer is set to 615V, and the rated open-circuit voltage on the grid side is set to 9377V. Considering voltage fluctuations and to improve output voltage accuracy, the tap position on the primary side of the rectifier transformer is retained, with a setting value of ±2×3%.

[0093] Referring to equation (5), based on the ratio of the primary and secondary sides of the transformer, the voltage that needs to be input to the grid side of the rectifier transformer, i.e. the voltage that needs to be output from the secondary side of the autotransformer, is calculated in sequence.

[0094] (5)

[0095] in, This refers to the voltage transformation ratio between the grid side and the valve side of the rectifier transformer. This refers to the number of turns in the rated tap winding on the grid side of the rectifier transformer. This refers to the number of turns in the valve-side winding of the rectifier transformer. This is the rated no-load voltage on the grid side of the rectifier transformer. This refers to the rated no-load voltage on the valve side of the rectifier transformer. The voltages required to be output from the valve side of the rectifier transformer. represents the voltage levels that need to be input to the grid side of the rectifier transformer, and n represents the tap level of the on-load tap changer.

[0096] The valve-side voltage, grid-side voltage, and secondary-side voltage of the rectifier transformer at different tap levels are summarized in Table 4.

[0097] Table 4. Secondary voltage values ​​of autotransformers

[0098] Based on the actual working conditions, all the above values ​​meet the safety requirements.

[0099] 3. Based on the input voltage value of the rectifier transformer grid side, obtain the rated current value of the primary side of the autotransformer and the corresponding current value of each tap on the secondary side.

[0100] Since the rated capacity of the autotransformer is 6600kVA, the rated primary current value is obtained according to equation (6). :

[0101] (6)

[0102] in, Rated capacity kVA, The primary side rated voltage V; then, according to equation (7), the current values ​​of each position on the secondary side are obtained. :

[0103] (7)

[0104] in, For rated capacity, This is the output voltage of the secondary side of the autotransformer, and also the input voltage of each tap on the grid side of the rectifier transformer.

[0105] 4. Compile a table based on the primary and secondary current values ​​of different taps of the autotransformer.

[0106] Table 5 Primary and secondary current values ​​of autotransformers

[0107] Since the maximum current limit of the on-load tap changer is 500A, and considering the actual operating conditions, the autotransformer at speeds 9 through 7 will reduce its power output to 4400kVA. At this point, the input and output voltages and capacity of the autotransformer are all determined. These are summarized in Table 6.

[0108] Table 6 Input and Output Voltages and Capacities of Autotransformers

[0109] The magnetic flux density of the rectifier transformer should be designed according to the highest tap voltage of 11405V. The cross-sectional area of ​​the conductors on the grid side and valve side should be considered according to the grid side input voltage of 8020V. The capacity of the 9th to 7th taps is 4400kVA.

[0110] Referring to the table above, the autotransformer can be designed as needed.

[0111] 5. Conduct a voltage surge test. With the train operating in traction / electric mode, rapidly adjust the grid voltage using a remote voltage regulator under the following conditions: In traction mode, adjust the grid voltage from 1500V to approximately 1650V, i.e., adjust the on-load tap changer from position 4 to position 3, with the autotransformer's input voltage from 9377V to 10063V. In electric mode, adjust the grid voltage from 1500V to approximately 1350V, i.e., adjust the on-load tap changer from position 4 to position 6, with the autotransformer's input voltage from 9377V to 8020V. Fine-tune the voltage using the rectifier transformer's own tap position to meet actual operating conditions. It should be noted that the autotransformer's voltage is adjusted remotely via on-load tap changer, remote control, remote signaling, remote adjustment, or remote measurement.

[0112] 6. Conduct a voltage fluctuation test by adjusting the mains voltage from 1000V to 1900V, and then from 1900V back to 1000V. Referring to Table 1, the voltage is adjusted step by step from level 9 to level 1, and then from level 1 back to level 9, with an adjustment step size of 112.5V. One round trip of voltage adjustment is considered one test, and the test is performed a total of 3 times.

[0113] This invention, while retaining the functions of a 24-pulse rectifier unit, offers advantages such as large capacity, wide voltage regulation range, high line reliability, synchronous and step-by-step voltage regulation of the rectifier unit, overcoming the current limitations of the voltage regulator controller (on-load tap changer), and separate on-site and remote control capabilities. This invention overcomes the current limitations of the voltage regulator controller (on-load tap changer), enabling wide-range voltage regulation of the rectifier unit's valve-side DC voltage output from 1000V to 1900V. It allows for on-site manual and remote online gear adjustment, and through secondary software development, step-by-step gear adjustment can be achieved, enabling multiple sudden increases and decreases. Simultaneously, it overcomes the limitations of the rectifier transformer's phase-shifting coils and main coil taps, which restrict space arrangement, maintaining the simplicity of the rectifier unit design.

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A 24-pulse DC generator set for performance testing of traction locomotives, characterized in that, include: An autotransformer, wherein the autotransformer includes a first coil group and a second coil group that are axially split and connected in parallel; An on-load tap changer electrically connected to the autotransformer; And two parallel rectifier branches, which are electrically connected to the on-load tap changer; The rectifier branch includes a circuit breaker electrically connected to an on-load tap changer, a rectifier transformer electrically connected to the circuit breaker, and a rectifier electrically connected to the rectifier transformer. The autotransformer leads out to the input terminal of the 24-pulse DC generator set, and the rectifier leads out to the output terminal of the 24-pulse DC generator set; The first coil group and the second coil group have the same structure; The first coil group is Y-shaped and includes a first phase coil, a second phase coil, and a third phase coil with one-to-one tap points; The tap point in the first coil group is connected to the corresponding tap point in the second coil group; The tap connected to the first phase coil leads to the secondary side a contact, the tap connected to the second phase coil leads to the secondary side b contact, and the tap connected to the third phase coil leads to the secondary side c contact. The rectifier in one rectifier branch is the first rectifier, and the rectifier in the other rectifier branch is the second rectifier. The rectifier includes a first output terminal and a second output terminal. The first output terminal of the first rectifier is led out to the positive output terminal of the 24-pulse DC generator. The second output terminal of the first rectifier is connected to the first output terminal of the second rectifier. The second output terminal of the second rectifier is led out to the negative output terminal of the 24-pulse DC generator. The method for testing the performance of traction locomotives using the 24-pulse DC generator set includes the following steps: S1: Determine the target output DC voltage value of the rectifier according to the performance test requirements, and determine the valve-side no-load voltage value of the rectifier transformer from the target output DC voltage value; S2: Determine the grid-side input voltage of the rectifier transformer based on the valve-side no-load voltage value of the rectifier transformer; S3: Determine the voltage and current values ​​of each tap on the secondary side of the autotransformer based on the grid-side input voltage value of the rectifier transformer; S4: The autotransformer is powered by the primary side rated voltage, and the actual output DC voltage of the rectifier is the target output DC voltage. This is used to perform performance testing on the power supply to the traction locomotive.

2. The 24-pulse DC generator set for traction locomotive performance testing according to claim 1, characterized in that, The on-load tap changer has nine tap stages, and the output voltage difference of the DC unit between two adjacent tap stages is 112.5V.

3. A test method for a 24-pulse DC generator set used for performance testing of traction locomotives, characterized in that, The 24-pulse DC generator set for traction locomotive performance testing as described in claim 1 or 2 includes the following steps: S1: Determine the target output DC voltage value of the rectifier according to the performance test requirements, and determine the valve-side no-load voltage value of the rectifier transformer from the target output DC voltage value; S2: Determine the grid-side input voltage of the rectifier transformer based on the valve-side no-load voltage value of the rectifier transformer; S3: Determine the voltage and current values ​​of each tap on the secondary side of the autotransformer based on the grid-side input voltage value of the rectifier transformer; S4: The autotransformer is powered by the primary side rated voltage, and the actual output DC voltage of the rectifier is the target output DC voltage. This is used to perform performance testing on the power supply to the traction locomotive.

4. The test method for a 24-pulse DC generator set for traction locomotive performance testing according to claim 3, characterized in that, In step S1: Obtain the specified no-load DC voltage using equation (1) : （1） Of this, 6% represents the voltage regulation rate of the rectifier unit. This is the rated voltage of the rectifier unit; The 24-pulse ideal no-load DC voltage is obtained by equation (2). : (2) in, To define the no-load DC voltage; The rated no-load voltage on the valve side of the rectifier transformer is obtained by formula (3). With 24 pulses ideal no-load DC voltage Physical relationship: （3） in, Angular frequency; The rated no-load voltage on the valve side of the rectifier transformer is obtained according to equation (4). : （4）。 5. The test method for a 24-pulse DC generator set for traction locomotive performance testing according to claim 4, characterized in that, In step S2: Referring to formula (5), determine the rated voltage of the grid side and the rated voltage of the valve side of the rectifier transformer according to the actual working conditions. Based on the relationship between the primary and secondary voltages of the transformer and the turns ratio, calculate the voltage required to be input to each tap of the grid side of the rectifier transformer, that is, the voltage value required to be output to each tap of the secondary side of the autotransformer. （5） in, This refers to the voltage transformation ratio between the grid side and the valve side of the rectifier transformer. This refers to the number of turns in the rated tap winding on the grid side of the rectifier transformer. This refers to the number of turns in the valve-side winding of the rectifier transformer. This is the rated no-load voltage on the grid side of the rectifier transformer. This refers to the rated no-load voltage on the valve side of the rectifier transformer. The voltages required to be output from the valve side of the rectifier transformer. represents the voltage levels that need to be input to the grid side of the rectifier transformer, and n represents the tap level of the on-load tap changer.

6. The test method for a 24-pulse DC generator set for traction locomotive performance testing according to claim 5, characterized in that, In step S3, the rated current value of the primary side of the autotransformer is obtained according to equation (6). : （6） in, This refers to the rated capacity of the autotransformer. This is the rated no-load voltage of the primary side of the autotransformer; The current values ​​of each stage on the secondary side of the autotransformer are obtained according to equation (7): （7） in, This refers to the rated capacity of the autotransformer. These are the no-load voltage values ​​of each stage on the secondary side of the autotransformer. .

7. The test method for a 24-pulse DC generator set for traction locomotive performance testing according to claim 3, characterized in that, The nine tap stages of the on-load tap changer correspond to the nine output voltage positions of the DC generator set, from low to high as follows: 1000V / 1112.5V / 1225V / 1337.5V / 1450V / 1562.5V / 1675V / 1787.5V / 1900V. The above voltage values ​​correspond to positions 9 to 1 of the on-load tap changer, with position 9 being the lowest and position 1 being the highest.

8. The test method for a 24-pulse DC generator set for traction locomotive performance testing according to claim 7, characterized in that, When the on-load tap changer is in positions 9, 8, and 7, the capacity of the autotransformer is set to 4400 kVA. When the on-load tap changer is in other positions, the capacity of the autotransformer is set to 6600 kVA.

9. The test method for a 24-pulse DC generator set for traction locomotive performance testing according to claim 3, characterized in that: The secondary voltage value of the autotransformer corresponding to the target output DC voltage value of the rectifier in each gear position is calculated through steps S1-S3 and compiled into a table. During testing, the corresponding on-load tap changer adjustment gear can be obtained by directly looking up the table based on the target output DC voltage value.

10. A test method for a 24-pulse DC generator set for traction locomotive performance testing according to claim 7, characterized in that, When conducting voltage surge tests, under simulated traction conditions, the target output DC voltage is adjusted from 1500V to 1650V, and the on-load tap changer is adjusted from position 4 to position 3 by referring to the table; under simulated electrical conditions, the target output DC voltage is adjusted from 1500V to 1350V, and the on-load tap changer is adjusted from position 4 to position 6 by referring to the table.

11. The test method for a 24-pulse DC generator set for traction locomotive performance testing according to claim 7, characterized in that, When conducting voltage fluctuation tests, the target output DC voltage value is adjusted back and forth from 1000V to 1900V. The on-load tap changer is adjusted step by step from 9th position to 1st position, and then from 1st position to 9th position, and this process is repeated 3 times.

12. The test method for a 24-pulse DC generator set for traction locomotive performance testing according to claim 3, characterized in that, Adjust the tap position using an on-load tap changer via remote control, remote signaling, remote adjustment, or remote measurement.

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