Large-current test method and system for direct-current ice melting device

Abstract

The invention relates to a high-current test method and system for a direct-current ice melting device, and the method comprises the steps: obtaining a high-current test result of the direct-current ice melting device when an ice melting transformer of the direct-current ice melting device operates at each gear, the direct-current output side of the direct-current ice melting device is in short circuit, and the voltage, the active power and the reactive power of the input side of the direct-current ice melting device under the preset test current flow through a rectifier of the direct-current ice melting device; taking the gears of the voltage, the active power and the reactive power of the input side of the direct-current ice melting device meeting preset conditions as preset gears; and controlling the DC output side of the DC ice melting device to be in short circuit, adjusting the gear of an ice melting transformer of the DC ice melting device to a preset gear, and carrying out a test. According to the technical scheme of the invention, the large-current test can be completed under the condition that the internal wiring of the DC deicing device is not changed, and the on-site wiring workload can be remarkably reduced, so that the routine maintenance test of the DC deicing device is facilitated.

Description

Technical Field

[0001] The present disclosure relates to the field of electrical engineering technology, and in particular to a high current test method and system for a direct current ice melting device. Background Art

[0002] In recent years, my country has encountered multiple rounds of large-scale rain, snow and freezing weather, which has brought huge challenges to the safe operation and supply of power grids. DC de-icing is an important means to deal with icing disasters on transmission lines. When the line icing reaches a certain level, timely de-icing operations can effectively avoid icing disasters. Since 2008, China has deployed hundreds of DC de-icing devices for transmission lines, and the number has been growing rapidly in the past three years.

[0003] Since the de-icing device is an emergency equipment used only in the winter icing period, in order to ensure that the de-icing device can be put into use in time after the line is iced, it must be put into operation after commissioning tests are carried out after the de-icing device is installed; and since the de-icing device is only put into operation when de-icing is required during the icing period, routine maintenance tests must be carried out before winter every year to ensure that the de-icing device is in good condition and ready for use at any time. For this reason, the de-icing function test must be carried out when the de-icing device is not connected to the grid.

[0004] Because the rated capacity of mobile DC ice-melting devices for transmission lines is generally several megawatts or even hundreds of megawatts, it is difficult to obtain a large enough test system capacity under laboratory conditions to carry out full-power assessment tests of the ice-melting device. Since DC ice-melting devices are generally composed of core components such as transformers and rectifiers, the existing test methods are to test the transformer and rectifier monomers, with the focus on low-voltage and high-current tests and no-load boost tests on rectifier monomers. According to many years of experience in maintenance tests and field applications of DC ice-melting equipment, high-current tests are the key to assessing ice-melting devices and are also the key items that are most likely to discover defects and hidden dangers in the device. The current high-current test method for ice-melting devices is generally to conduct a single-body rectifier current flow test, that is, before the test, the connecting copper bus or cable between the ice-melting transformer and the rectifier is untied, and a low-voltage and high-current 12-pulse test transformer is temporarily connected to the input side of the rectifier as a boost transformer, and then added to the 12-pulse rectifier for high-current assessment, and the current waveform, temperature rise and control measurement data during the flow process are observed and compared with the expected values. After the test, normal wiring is restored. This method has the following problems: On the one hand, it requires a special 12-pulse current-raising test transformer and a large number of test connection cables. The test equipment is large, and the equipment transportation and lifting are troublesome, resulting in high test costs. On the other hand, the test current is large, the cables are bulky, the number of connectors is large, the on-site wiring task is heavy, and the test efficiency is low. Taking the current mainstream 18MW / 9kV / 2000A DC ice melting device as an example, its 12-pulse rectifier has a rated input current of 1864A. During the test, 18 LGJ-185 test cables are generally required to connect the test current-raising transformer and the rectifier under test. The cable length needs to connect the external current-raising transformer and the rectifier. The length of each test cable is generally not less than 10m. On-site wiring is troublesome. Generally, the current-passing test only takes 1-2 hours, but the wiring before the test and the recovery wiring after the test take 1-2 days. The workload of moving and wiring cables is time-consuming and labor-intensive, which restricts the low test efficiency. In addition, this method can only check the rectifier unit and cannot detect the overall current-carrying capacity of the DC ice-melting device. Moreover, the internal copper busbars or cables of the ice-melting device need to be disconnected before and after the test and restored after the test. Repeated disconnection and connection of the internal copper busbars of the ice-melting device during the maintenance process itself can easily bring new equipment hazards. Summary of the invention

[0005] In order to solve the above technical problems or at least partially solve the above technical problems, the present disclosure provides a high current test method and system for a DC ice melting device, which can complete the high current test without changing the internal wiring of the DC ice melting device, and can significantly reduce the workload of on-site wiring, thereby facilitating routine maintenance tests of the DC ice melting device.

[0006] In a first aspect, the present disclosure provides a high current test method for a DC ice melting device, comprising:

[0007] Obtaining the voltage, active power and reactive power of the input side of the DC ice-melting device when the ice-melting transformer of the DC ice-melting device is operating at various gears, the DC output side of the DC ice-melting device is short-circuited and the rectifier of the DC ice-melting device flows through a preset test current;

[0008] The voltage, active power and reactive power at the input side of the DC ice-melting device satisfying the preset conditions are used as the preset gear of the ice-melting transformer;

[0009] Controlling the DC output side of the DC ice-melting device to be short-circuited, and adjusting the gear position of the ice-melting transformer to a preset gear position;

[0010] Controlling the test voltage source to gradually increase the output voltage of the test voltage source until the output current of the rectifier reaches the preset test current;

[0011] The output current of the rectifier is maintained at the preset test current for a preset time period, and based on the output current of the DC ice melting device belonging to a preset current range, and / or the operating temperature of the DC ice melting device belonging to a preset temperature range, it is determined that the DC ice melting device test is qualified.

[0012] Optionally, the step of obtaining the voltage, active power, and reactive power at the input side of the DC ice-melting device when the ice-melting transformer of the DC ice-melting device is operating at various gears, the DC output side of the DC ice-melting device is short-circuited, and a rectifier of the DC ice-melting device flows through a preset test current, includes:

[0013] Obtaining the short-circuit impedance of each gear of the ice-melting transformer of the DC ice-melting device;

[0014] Obtaining a conduction voltage drop of a rectifier of the DC ice melting device under the preset test current;

[0015] Building an equivalent electrical model of the DC ice melting device when the DC output side is short-circuited;

[0016] According to the equivalent electrical model, the short-circuit impedance of each gear of the ice-melting transformer of the DC ice-melting device and the conduction voltage drop of the rectifier of the DC ice-melting device under the preset test current, the voltage, active power and reactive power of the input side of the DC ice-melting device under the preset test current are obtained when the ice-melting transformer of the DC ice-melting device is operating at each gear, the DC output side of the DC ice-melting device is short-circuited and the rectifier of the DC ice-melting device flows through the DC ice-melting device.

[0017] Optionally, the step of taking the voltage, active power and reactive power at the input side of the DC ice melting device as the preset gear at which the voltage, active power and reactive power meet preset conditions includes:

[0018] The gear position at which the voltage at the input side of the DC ice melting device belongs to a preset voltage range, the active power is less than or equal to a first power threshold, and the reactive power is less than or equal to a second power threshold is used as a preset gear position.

[0019] Optionally, the high current test method for the DC ice melting device also includes:

[0020] Based on the fact that the output current of the DC ice melting device does not belong to the preset current range and / or the operating temperature of the DC ice melting device does not belong to the preset temperature range, it is determined that the DC ice melting device is operating abnormally, and control is performed to disconnect the electrical connection between the test voltage source and the external power supply.

[0021] Optionally, after determining that the DC ice melting device is qualified, the method further includes:

[0022] The voltage of the test voltage source is controlled to return to zero, so that the DC ice melting device is restored to the state before the test.

[0023] In a second aspect, the present disclosure further provides a high current test system for a DC ice melting device, comprising:

[0024] DC ice melting device and test platform;

[0025] The DC ice-melting device comprises: an ice-melting transformer, a rectifier and an ice-melting knife switch;

[0026] The secondary side of the ice-melting transformer is electrically connected to the input side of the rectifier, the output side of the rectifier is electrically connected to the input side of the ice-melting knife switch, the output side of the ice-melting knife switch serves as the output side of the DC ice-melting device, and the primary side of the ice-melting transformer serves as the input side of the DC ice-melting device;

[0027] The test platform comprises: a test voltage source and a capacitor bank;

[0028] The first end of the test voltage source is connected to an external power supply, and the second end of the test voltage source and the first end of the capacitor bank are both electrically connected to the primary side of the ice-melting transformer;

[0029] Wherein, when the output side of the DC ice-melting device is short-circuited and the ice-melting transformer of the DC ice-melting device is in a preset gear, the test voltage source is controlled to gradually increase the output voltage of the test voltage source until the output current of the rectifier reaches a preset current value, and the capacitor group is used to compensate for the internal impedance voltage drop of the ice-melting transformer.

[0030] Optionally, the high current test system for a DC ice melting device further comprises: a measuring protection device; the test platform further comprises: a test switch;

[0031] The test switch is connected in series between the test voltage source and the external power supply, the first end of the measurement protection device is electrically connected to the test switch, and the second end of the measurement protection device is electrically connected to the DC ice melting device;

[0032] The measuring and protecting device is used for controlling the on and off of the test switch according to the output current of the DC ice-melting device and / or the working temperature of the DC ice-melting device.

[0033] Optionally, the rated output voltage of the test voltage source and the rated voltage of the capacitor group are the voltage at the input side of the DC ice-melting device when the output side of the DC ice-melting device is short-circuited and the ice-melting transformer is in a preset gear, and the output current of the rectifier reaches the preset test current value; the rated output capacity of the test voltage source is the active power of the input side of the DC ice-melting device when the output side of the DC ice-melting device is short-circuited and the ice-melting transformer is in a preset gear, and the rated output capacity of the capacitor group is the reactive power of the input side of the DC ice-melting device when the output side of the DC ice-melting device is short-circuited and the ice-melting transformer is in a preset gear, and the output current of the rectifier reaches the preset test current.

[0034] Optionally, the DC ice melting device and the test platform are detachably electrically connected via a test cable.

[0035] In a third aspect, the present disclosure further provides a processing device, including a processor and a memory, wherein the processor executes the steps of the high current test method for a DC ice melting device as described in the first aspect by calling a program or instruction stored in the memory.

[0036] Compared with the prior art, the technical solution provided by the embodiments of the present disclosure has the following advantages:

[0037] The disclosed embodiments provide a high-current test method and system for a DC ice-melting device. The high-current test method for a DC ice-melting device includes obtaining the voltage, active power, and reactive power of the input side of the DC ice-melting device under a preset test current when the DC ice-melting device's ice-melting transformer is operating at various gears, the DC output side of the DC ice-melting device is short-circuited, and the rectifier of the DC ice-melting device flows through the DC ice-melting device; taking the gear at which the voltage, active power, and reactive power of the input side of the DC ice-melting device meet preset conditions as the preset gear; controlling the DC output side of the DC ice-melting device to be short-circuited, and adjusting the gear of the ice-melting transformer of the DC ice-melting device to the preset gear; controlling the test voltage source to gradually increase the output voltage of the test voltage source until the output current of the rectifier of the DC ice-melting device reaches the preset test current; maintaining the output current of the rectifier to reach the preset test current for a preset time, and determining that the DC ice-melting device is qualified based on the output current of the DC ice-melting device belonging to the preset current range and / or the operating temperature of the DC ice-melting device belonging to the preset temperature range. Therefore, by setting the input voltage, active power and reactive power of the DC ice melting device to the preset level as the preset level, the ice melting transformer is adjusted to the preset level and the test is carried out, the accuracy of the test is improved, and the large current test is completed without changing the internal wiring of the DC ice melting device, which can significantly reduce the workload of on-site wiring, thereby facilitating routine maintenance testing of the ice melting device. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0040] Figure 1 A schematic flow chart of a high current test method for a DC ice melting device provided in an embodiment of the present disclosure;

[0041] Figure 2 An equivalent electrical model of a DC ice melting device provided by an embodiment of the present disclosure when the DC output side is short-circuited;

[0042] Figure 3 A high current test system for a DC ice melting device provided in an embodiment of the present disclosure;

[0043] Figure 4 A schematic diagram of the structure of a processing device provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0044] In order to more clearly understand the above-mentioned objectives, features and advantages of the present disclosure, the scheme of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0045] In the following description, many specific details are set forth to facilitate a full understanding of the present disclosure, but the present disclosure may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present disclosure, rather than all of the embodiments.

[0046] The present disclosure provides a high current test method for a DC ice melting device. Figure 1 The present invention provides a flow chart of a high current test method for a DC ice melting device. The mode switching method can be applied to application scenarios where a high current test of a DC ice melting device is required. Figure 1 As shown, the high current test method for DC ice melting device includes:

[0047] S101, obtaining the voltage, active power, and reactive power of the input side of the DC ice-melting device under a preset test current flowing through the rectifier of the DC ice-melting device when the ice-melting transformer of the DC ice-melting device is operating at various gears and the DC output side of the DC ice-melting device is short-circuited.

[0048] Optionally, the input voltage, active power and reactive power of the DC ice-melting device under a preset test current is obtained when the ice-melting transformer of the DC ice-melting device operates at various gears, the DC output side of the DC ice-melting device is short-circuited and the rectifier of the DC ice-melting device flows through it, including: obtaining the short-circuit impedance of the ice-melting transformer of the DC ice-melting device at various gears; obtaining the conduction voltage drop of the rectifier of the DC ice-melting device under the preset test current; building an equivalent electrical model when the DC output side of the DC ice-melting device is short-circuited; according to the equivalent electrical model, the short-circuit impedance of the ice-melting transformer of the DC ice-melting device at various gears and the conduction voltage drop of the rectifier of the DC ice-melting device under the preset test current, obtaining the voltage, active power and reactive power of the input side of the DC ice-melting device under the preset test current when the ice-melting transformer of the DC ice-melting device operates at various gears, the DC output side of the DC ice-melting device is short-circuited and the rectifier of the DC ice-melting device flows through it.

[0049] Specifically, the short-circuit impedance of the ice-melting transformer is expressed as an equivalent resistance in series with reactance, and its value can be directly calculated from the short-circuit impedance, load loss, and parameters of the current gear marked on the transformer nameplate, simplified by per-unit value, and converted into actual value.

[0050] The inductive reactance and internal resistance in the transformer short-circuit impedance can be expressed as:

[0051] X 21 =U 1k %

[0052]

[0053] Among them, X 21 It represents the internal inductive reactance of the short-circuit impedance of the ice-melting transformer in the current gear, R 21 Indicates the internal resistance of the ice melting transformer in the short-circuit impedance at the current gear, U 1k % represents the impedance per unit value of the ice melting transformer at the current gear, P TN Indicates the load loss of the ice melting transformer at the current gear, S TN Indicates the output capacity of the ice-melting transformer at the current gear.

[0054] It should be noted that when the nameplate lacks short-circuit impedance data or the accuracy of the marked data is in doubt, a transformer short-circuit impedance tester can be used to directly measure the short-circuit impedance of the ice-melting transformer, which is not limited in this embodiment of the present disclosure.

[0055] The rectifier of the DC ice melting device may include, for example, a diode rectifier bridge, and the on-state voltage drop of the diode rectifier bridge may be calculated by referring to the diode data parameter table to measure its on-state voltage drop when a predetermined test current passes through it. Exemplarily, the on-state voltage drop of the diode rectifier bridge may also be directly measured when the output side of the DC ice melting device is short-circuited and an adjustable three-phase voltage is applied to the input side until the output current reaches the predetermined test current. In order to avoid complex modeling, it is preferred to directly measure the on-state voltage drop of the rectifier when the predetermined test current flows through it and record the value as U D .

[0056] Figure 2 The equivalent electrical model of a DC de-icing device provided in the embodiment of the present disclosure when the DC output side is short-circuited includes an equivalent rectifier and an equivalent de-icing transformer. For the sake of clear explanation, the equivalent rectifier is referred to as a rectifier and the equivalent de-icing transformer is referred to as an de-icing transformer in the embodiment of the present disclosure. Figure 2 As shown, the current relationship between the AC and DC sides of the rectifier is:

[0057] I2=k dc I dc =0.816I dc

[0058] Where, I2 represents the AC input current of the rectifier, I dc represents the DC output current of the rectifier, k dck represents the current conversion coefficient between the AC side and the DC side of the rectifier. For example, the rectifier in the DC ice melting device is a 6-pulse constant current rectifier structure. dc is set to a fixed value of 0.816. It will be appreciated that when other types of rectifiers are used, k dc It can be changed accordingly, so I won’t go into details here.

[0059] When the DC side of the DC ice melting device is short-circuited, the voltage and current relationship on the AC input side of the rectifier is:

[0060] U2=U D0 +r D I2

[0061] In which, taking the rectifier as a diode rectifier as an example, U2 represents the effective value of the rectifier's AC input voltage, U D0 It represents the equivalent voltage drop of the diode in the rectifier (not DC conduction, converted to effective value), r D It represents the equivalent resistance of the diode when it is turned on, and I2 represents the AC input current of the rectifier.

[0062] For the transformer, the voltage and current relationship between the primary and secondary sides of the transformer is:

[0063]

[0064] Among them, U1 represents the voltage on the primary input side of the ice-melting transformer, I1 represents the current on the primary input side of the ice-melting transformer, U2 represents the voltage on the secondary output side of the ice-melting transformer, I2 represents the current on the secondary output side of the ice-melting transformer, R1 represents the resistance inside the primary side of the ice-melting transformer, X1 represents the inductive reactance inside the primary side of the ice-melting transformer, R2 represents the resistance inside the secondary side of the ice-melting transformer, X2 represents the inductive reactance inside the secondary side of the ice-melting transformer, R 21 The internal impedance of the primary and secondary sides of the ice melting transformer is converted to the internal resistance of the primary side, X 21 It represents the internal inductive reactance when the internal impedance of the primary and secondary sides of the ice-melting transformer is uniformly converted to the primary side, that is, its short-circuit impedance. n represents the voltage transformation ratio between the primary and secondary sides of the ice-melting transformer. j represents the complex vector.

[0065] From the input side of the DC ice melting device, the total active power loss and reactive power loss absorbed by the DC ice melting device can be expressed as:

[0066]

[0067] Among them, P T Indicates the active power loss of the ice-melting transformer, P D Indicates the active power loss of the rectifier.

[0068] Since the rectifier does not absorb active power, the reactive power loss Q1 absorbed by the DC ice melting device as a whole is:

[0069] Q1=X 21 I2 2

[0070] The following is an example of a DC ice-melting device with a rated output parameter of 18MW / 9kV / 2000A. The ice-melting transformer in the DC ice-melting device is a 14.2MVA 12-pulse rectifier transformer. The preset test current of the DC ice-melting device is set to 2000A. According to the above steps and the nameplate parameters of the ice-melting transformer, the input voltage, current, active power and reactive power of the DC ice-melting device input side, that is, the primary side of the ice-melting transformer, can be obtained when the DC ice-melting device is conducting a large current test. The results are shown in Table 1, which includes the relevant parameters of the ice-melting transformer, the relevant parameters of the rectifier, and the relevant test parameters of the ice-melting transformer in various gears. It should be noted that the test conditions are that the ice-melting transformer is running at the corresponding gear, the DC output side of the DC ice-melting device is short-circuited, and the rectifier of the DC ice-melting device flows through the preset test current. The test conditions described in the subsequent embodiments can be understood in this way.

[0071] Table 1

[0072]

[0073] S102: The input voltage, active power and reactive power of the DC ice-melting device satisfying preset conditions are used as the preset gear of the ice-melting transformer.

[0074] Optionally, the gear position at which the voltage, active power and reactive power on the input side of the DC ice melting device meet preset conditions is used as the preset gear position, including: the gear position at which the voltage on the input side of the DC ice melting device belongs to a preset voltage range, the active power is less than or equal to a first power threshold, and the reactive power is less than or equal to a second power threshold is used as the preset gear position.

[0075] Specifically, the input voltage, active power and reactive power of the DC ice melting device under each gear can be compared, and the gear that is most easily implemented is selected as the preset gear, and the input voltage, active power and reactive power of the DC ice melting device corresponding to this time are recorded. The gear that is most easily implemented is the gear that is easiest to build a test voltage source under test conditions. For example, a preset voltage range, a first power threshold and a second power threshold can be set in advance according to the test conditions, and a gear in which the input voltage of the DC ice melting device belongs to the preset voltage range, the active power is less than or equal to the first power threshold, and the reactive power is less than or equal to the second power threshold is used as the preset gear.

[0076] For example, according to the data in Table 1, the lowest gear of the ice melting transformer, that is, the gear with a secondary side voltage of 1040V, is used as the preset gear, and all its input voltages, active power and reactive power are the smallest, which is also the easiest to achieve under laboratory conditions. At this time, when a large current test is carried out at the preset gear, the input voltage of the DC ice melting device is 265V, the active power is 339kW, and the reactive power is 196kvar.

[0077] S103, controlling the DC output side of the DC ice-melting device to be short-circuited, and adjusting the gear position of the ice-melting transformer to a preset gear position.

[0078] Exemplarily, controlling the short circuit of the DC output side of the DC ice-melting device may be to connect a three-phase ice-melting short circuit wire between three phases of the DC output side of the DC ice-melting device, and the current passing through the short circuit wire is not less than a preset test current.

[0079] S104, controlling the test voltage source to gradually increase the output voltage of the test voltage source until the output current of the rectifier reaches a preset test current.

[0080] Exemplarily, the output voltage of the test voltage source is gradually increased from zero until it is observed that the output current of the rectifier reaches a preset test current.

[0081] S105. Maintaining the state where the output current of the rectifier reaches a preset test current for a preset time period, and determining that the DC ice melting device has passed the test based on that the output current of the DC ice melting device belongs to a preset current range and / or that the operating temperature of the DC ice melting device belongs to a preset temperature range.

[0082] Specifically, the output current of the rectifier is maintained to reach a preset test current for a certain preset time, and the output current of the DC ice melting device is continuously monitored within the preset time, and the output current is compared with the preset current interval. If the output current belongs to the preset current interval, it is determined that the DC ice melting device has passed the test. And / or, the working temperature of the DC ice melting device is continuously monitored within the preset time, and the working temperature is compared with the preset temperature interval. If the working temperature belongs to the preset temperature interval, it is determined that the DC ice melting device has passed the test.

[0083] It should be noted that the preset duration, preset current range and preset temperature range can be set according to the actual test requirements of the DC ice melting device, and the embodiments of the present disclosure are not limited to this.

[0084] Optionally, the high current test method for a DC ice melting device further includes: based on the output current of the DC ice melting device not belonging to a preset current range, and / or the operating temperature of the DC ice melting device not belonging to a preset temperature range, determining that the DC ice melting device is operating abnormally, and controlling to disconnect the electrical connection between the test voltage source and the external power supply.

[0085] Specifically, when the output current of the DC ice melting device does not belong to the preset current range, and / or the operating temperature of the DC ice melting device does not belong to the preset temperature range, it means that the DC ice melting device is operating abnormally, and the electrical connection between the test voltage source and the external power supply is disconnected to avoid burning the DC ice melting device, and the staff can be prompted to perform maintenance.

[0086] Optionally, after determining that the DC ice melting device has passed the test, the method further includes: controlling the voltage of the test voltage source to return to zero, so that the DC ice melting device returns to a state before the test.

[0087] Specifically, after the test is completed, the voltage of the test voltage source is adjusted to zero and the power is turned off, the test cable is removed, and the DC ice melting device is restored to the initial state of normal operation, and the high current test of the DC ice melting device is completed.

[0088] The high-current test method for a DC ice-melting device provided in the embodiment of the present disclosure improves the accuracy of the test by setting the input voltage, active power and reactive power of the DC ice-melting device to a gear that meets preset conditions as a preset gear, adjusting the ice-melting transformer to the preset gear and conducting the test during the test, and completing the high-current test without changing the internal wiring of the DC ice-melting device, which can significantly reduce the workload of on-site wiring, thereby facilitating routine maintenance testing of the ice-melting device.

[0089] Figure 3 A high current test system for a DC ice melting device is provided in an embodiment of the present disclosure, such as Figure 3 As shown, a high current test system for a DC ice-melting device comprises: a DC ice-melting device 1 and a test platform 2; the DC ice-melting device 1 comprises: an ice-melting transformer 11, a rectifier 12 and an ice-melting knife switch 13; the secondary side of the ice-melting transformer 11 is electrically connected to the input side of the rectifier 12, the output side of the rectifier 12 is electrically connected to the input side of the ice-melting knife switch 13, the output side of the ice-melting knife switch 13 serves as the output side of the DC ice-melting device 1, and the primary side of the ice-melting transformer 11 serves as the input side of the DC ice-melting device 1;

[0090] The test platform 2 includes: a test voltage source 21 and a capacitor group 22; the first end of the test voltage source 21 is connected to an external power supply, and the second end of the test voltage source 21 and the first end of the capacitor group 22 are both electrically connected to the primary side of the ice-melting transformer 11; wherein, the test voltage source 21 is used to be controlled to gradually increase the output voltage of the test voltage source 21 when the output side of the DC ice-melting device 1 is short-circuited and the ice-melting transformer 11 of the DC ice-melting device 1 is in a preset gear, until the output current of the rectifier 12 reaches the preset test current, and the capacitor group 22 is used to compensate for the internal impedance voltage drop of the ice-melting transformer 11.

[0091] Figure 3exemplarily shows that the test voltage source 21 and the capacitor bank 22 are connected in parallel, one end of the capacitor bank 22 and the second end of the test voltage source 21 are both electrically connected to the primary side of the ice melting transformer 11, and the other end of the capacitor bank 22 is closed. Compared with the connection mode of the test voltage source 21 and the capacitor bank 22 in series, the parallel connection of the test voltage source 21 and the capacitor bank 22 simplifies the connection mode of the capacitor bank 22, that is, it is easier to connect the capacitor bank 22 to the test platform, making the construction of the high current test system for the DC ice melting device 1 simpler.

[0092] During the high current test, the three-phase ice-melting short-circuit wire 6 can be connected between the three phases on the DC output side of the DC ice-melting device 1, and its current flow is not less than the preset test current. The test voltage source 21 is used to be short-circuited at the output side of the DC ice-melting device 1 and the ice-melting transformer 11 of the DC ice-melting device 1 is in a preset gear, and is controlled to gradually increase the output voltage of the test voltage source 21 until the output current of the rectifier 12 reaches the preset current value. The capacitor bank 22 is used to compensate for the internal impedance voltage drop of the ice-melting transformer 11 during the test. The power supply capacity required by the test platform 2 only needs to be not less than the active power consumption of the DC ice-melting device 1 at the preset gear, thereby reducing the power supply capacity demand of the test platform 2.

[0093] Alternatively, if Figure 3 As shown, the high current test system of the DC ice melting device also includes: a measuring protection device 3, and the test platform 2 also includes a test switch 23; the test switch 23 is connected in series between the test voltage source 21 and the external power supply, the first end of the measuring protection device 3 is electrically connected to the test switch 23, and the second end of the measuring protection device 3 is electrically connected to the DC ice melting device 1; the measuring protection device 3 is used to control the on and off of the test switch 23 according to the output current of the DC ice melting device 1, and / or the working temperature of the DC ice melting device 1.

[0094] Specifically, Figure 3 As shown, the measuring and protecting device 3 is electrically connected to the DC ice melting device 1 and the test switch 23, respectively. The measuring and protecting device 3 can detect the output current of the DC ice melting device 1. When the measuring and protecting device 3 detects that the output current is greater than the preset current threshold, the test switch 23 can be controlled to be disconnected to disconnect the electrical connection between the test voltage source 21 and the external power supply to avoid burning the DC ice melting device 1. The measuring and protecting device 3 can also detect the working temperature of the DC ice melting device 1. When the measuring and protecting device 3 detects that the working temperature is greater than the preset temperature threshold, the test switch 23 can be controlled to be disconnected to disconnect the electrical connection between the test voltage source 21 and the external power supply to avoid burning the DC ice melting device 1. Exemplarily, the measuring and protecting device 3 can be electrically connected to the test switch 23 through the protection trip signal line 4, thereby improving the reliability of the high current test system for the DC ice melting device 1 by using the measuring and protecting device 3 and the test switch 23.

[0095] Alternatively, if Figure 3 As shown, the rated output voltage of the test voltage source 21 and the rated voltage of the capacitor group 22 are the voltage of the input side of the DC ice-melting device 1 under the preset test current value when the output side of the DC ice-melting device 1 is short-circuited and the ice-melting transformer 11 of the DC ice-melting device 1 is at the preset gear, and the output current of the rectifier 12 reaches the active power of the input side of the DC ice-melting device 1 under the preset test current when the output side of the DC ice-melting device 1 is short-circuited and the ice-melting transformer 11 of the DC ice-melting device 1 is at the preset gear, and the rated output capacity of the capacitor group 22 is the reactive power of the input side of the DC ice-melting device 1 under the preset test current when the output side of the DC ice-melting device 1 is short-circuited and the ice-melting transformer 11 of the DC ice-melting device 1 is at the preset gear, and the output current of the rectifier 12 reaches the reactive power of the input side of the DC ice-melting device 1 under the preset test current.

[0096] Specifically, Figure 3 As shown, taking the data in Table 1 in the above embodiment as an example, it is calculated that when the output side of the DC ice-melting device 1 is short-circuited and the ice-melting transformer 11 of the DC ice-melting device 1 is in the preset gear, the input side voltage of the DC ice-melting device 1, that is, the primary voltage of the ice-melting transformer 11, is 265V, the input side current of the DC ice-melting device 1, that is, the primary current of the ice-melting transformer 11, is 339A, the input side active power of the DC ice-melting device 1, that is, the primary active power of the ice-melting transformer 11, is 91kW, and the input side reactive power of the DC ice-melting device 1, that is, the primary reactive power of the ice-melting transformer 11, is 196kvar. The ice-melting test voltage source 21 is selected as a conventional voltage regulator, whose rated output voltage is set to 265V and the rated output capacity is 91KVA respectively; the capacitor bank 22 has a rated voltage of 265V and a rated capacity equal to 196kvar.

[0097] Alternatively, if Figure 3 As shown, the DC ice melting device 1 and the test platform 2 are detachably electrically connected via a test cable 5 .

[0098] Specifically, Figure 3 As shown, when conducting a high current test, the current through the test cable 5 is much smaller than the rated input current of the rectifier 12, thereby greatly reducing the current requirement of the test cable 5 and the number of cables, and facilitating on-site cable wiring.

[0099] In addition, when conducting a high current test, there is no need to untie the internal wiring of the DC ice melting device 1, and the DC ice melting device 1 is kept normally connected, thereby avoiding the hidden dangers caused by disconnecting the wiring during the test; and the workload of on-site wiring is greatly reduced.

[0100] After the test is finished, the test cable 5 between the DC ice-melting device 1 and the test platform 2 is removed, and the DC ice-melting device 1 is restored to a normal connection state.

[0101] In some embodiments, the test voltage source 21 and the capacitor bank 22 may be integrated into a whole, thereby avoiding temporary connection of the capacitor bank wiring during the test and reducing the engineering workload of the test.

[0102] The present disclosure also provides a processing device, Figure 4 A schematic diagram of the structure of a processing device provided in an embodiment of the present disclosure. Figure 4 As shown, the processing device includes a processor and a memory. The processor executes the steps of the high current test method for a DC ice melting device as described in the above embodiment by calling the program or instructions stored in the memory. Therefore, it has the beneficial effects described in the above embodiment and will not be repeated here.

[0103] like Figure 4 As shown, the processing device may include at least one processor 401, at least one memory 402, and at least one communication interface 403. The various components in the processing device are coupled together via a bus system 404. The communication interface 403 is used to transmit information with external devices. It is understood that the bus system 404 is used to achieve connection and communication between these components. In addition to the data bus, the bus system 404 also includes a power bus, a control bus, and a status signal bus. However, for the sake of clarity, the bus system 404 is not described in detail. Figure 4 Various buses are labeled as bus system 404 .

[0104] It can be understood that the memory 402 in this embodiment can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories. In some embodiments, the memory 402 stores the following elements: executable units or data structures, or their subsets, or their extended sets of operating systems and applications. In the embodiment of the present disclosure, the processor 401 executes the steps of each embodiment of the high current test method for a DC ice melting device provided in the embodiment of the present disclosure by calling the program or instruction stored in the memory 402.

[0105] The high current test method for a DC ice melting device provided in the embodiment of the present disclosure can be applied to the processor 401, or implemented by the processor 401. The processor 401 can be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by an integrated logic circuit of hardware in the processor 401 or instructions in the form of software. The above-mentioned processor 401 can be a general-purpose processor, a digital signal processor (Digital Signal Processor, DSP), an application-specific integrated circuit (Application Specific Integrated Circuit, ASIC), a field programmable gate array (Field Programmable Gate Array, FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc.

[0106] The steps of the high current test method for a DC ice melting device provided in the embodiment of the present disclosure can be directly embodied as being executed by a hardware decoding processor, or can be executed by a combination of hardware and software units in the decoding processor. The software unit can be located in a mature storage medium in the art, such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory 402, and the processor 401 reads the information in the memory 402 and completes the steps of the method in combination with its hardware.

[0107] The processing device may also include one entity component, or multiple entity components, to implement the design of the railway traction network system according to the instructions generated by the processor 401 when executing the high current test method for the DC ice melting device provided in the embodiment of the present application. Different entity components can be set in the processing device, or outside the processing device, such as a cloud server, etc. Each entity component cooperates with the processor 401 and the memory 402 to implement the functions of the processing device in this embodiment.

[0108] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0109] The above are only specific embodiments of the present disclosure, so that those skilled in the art can understand or implement the present disclosure. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not be limited to these embodiments herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high current test method for a DC ice melting device, characterized in that: include: Obtaining the voltage, active power and reactive power of the input side of the DC ice-melting device when the ice-melting transformer of the DC ice-melting device is operating at various gears, the DC output side of the DC ice-melting device is short-circuited and the rectifier of the DC ice-melting device flows through a preset test current; The voltage, active power and reactive power at the input side of the DC ice-melting device satisfying the preset conditions are used as the preset gear of the ice-melting transformer; Controlling the DC output side of the DC ice-melting device to be short-circuited, and adjusting the gear position of the ice-melting transformer to a preset gear position; Controlling the test voltage source to gradually increase the output voltage of the test voltage source until the output current of the rectifier reaches the preset test current; The output current of the rectifier is maintained at the preset test current for a preset time period, and based on the output current of the DC ice melting device belonging to a preset current range, and / or the operating temperature of the DC ice melting device belonging to a preset temperature range, it is determined that the DC ice melting device test is qualified.

2. The high current test method for a DC ice melting device according to claim 1, characterized in that: The step of obtaining the voltage, active power and reactive power of the input side of the DC ice-melting device when the ice-melting transformer of the DC ice-melting device is operating at various gears, the DC output side of the DC ice-melting device is short-circuited and the rectifier of the DC ice-melting device flows through a preset test current, includes: Obtaining the short-circuit impedance of each gear of the ice-melting transformer of the DC ice-melting device; Obtaining a conduction voltage drop of a rectifier of the DC ice melting device under the preset test current; Building an equivalent electrical model of the DC ice melting device when the DC output side is short-circuited; According to the equivalent electrical model, the short-circuit impedance of each gear of the ice-melting transformer of the DC ice-melting device and the conduction voltage drop of the rectifier of the DC ice-melting device under the preset test current, the voltage, active power and reactive power of the input side of the DC ice-melting device under the preset test current are obtained when the ice-melting transformer of the DC ice-melting device is operating at each gear, the DC output side of the DC ice-melting device is short-circuited and the rectifier of the DC ice-melting device flows through the DC ice-melting device.

3. The high current test method for a DC ice melting device according to claim 1, characterized in that: The step of using the voltage, active power and reactive power at the input side of the DC ice melting device that meet preset conditions as the preset gear of the ice melting transformer includes: The gear position at which the voltage at the input side of the DC ice melting device belongs to a preset voltage range, the active power is less than or equal to a first power threshold, and the reactive power is less than or equal to a second power threshold is used as a preset gear position.

4. The high current test method for a DC ice melting device according to claim 1, characterized in that: Also includes: Based on the fact that the output current of the DC ice melting device does not belong to the preset current range and / or the operating temperature of the DC ice melting device does not belong to the preset temperature range, it is determined that the DC ice melting device is operating abnormally, and control is performed to disconnect the electrical connection between the test voltage source and the external power supply.

5. The high current test method for a DC ice melting device according to claim 1, characterized in that: After determining that the DC ice melting device has passed the test, the method further includes: The voltage of the test voltage source is controlled to return to zero, so that the DC ice melting device is restored to the state before the test.

6. A high current test system for a DC ice melting device, characterized in that: include: DC ice melting device and test platform; The DC ice-melting device comprises: an ice-melting transformer, a rectifier and an ice-melting knife switch; The secondary side of the ice-melting transformer is electrically connected to the input side of the rectifier, the output side of the rectifier is electrically connected to the input side of the ice-melting knife switch, the output side of the ice-melting knife switch serves as the output side of the DC ice-melting device, and the primary side of the ice-melting transformer serves as the input side of the DC ice-melting device; The test platform comprises: a test voltage source and a capacitor bank; The first end of the test voltage source is connected to an external power supply, and the second end of the test voltage source and the first end of the capacitor bank are both electrically connected to the primary side of the ice-melting transformer; Wherein, when the output side of the DC ice-melting device is short-circuited and the ice-melting transformer of the DC ice-melting device is in a preset gear, the test voltage source is controlled to gradually increase the output voltage of the test voltage source until the output current of the rectifier reaches a preset current value, and the capacitor group is used to compensate for the internal impedance voltage drop of the ice-melting transformer.

7. The high current test system for a DC ice melting device according to claim 6, characterized in that: It also includes: a measuring protection device; the test platform also includes: a test switch; The test switch is connected in series between the test voltage source and the external power supply, the first end of the measurement protection device is electrically connected to the test switch, and the second end of the measurement protection device is electrically connected to the DC ice melting device; The measuring and protecting device is used for controlling the on and off of the test switch according to the output current of the DC ice-melting device and / or the working temperature of the DC ice-melting device.

8. The high current test system for a DC ice melting device according to claim 6, characterized in that: The rated output voltage of the test voltage source and the rated voltage of the capacitor bank are that when the output side of the DC ice-melting device is short-circuited and the ice-melting transformer is in a preset gear, the output current of the rectifier reaches the voltage on the input side of the DC ice-melting device under a preset test current; the rated output capacity of the test voltage source is that when the output side of the DC ice-melting device is short-circuited and the ice-melting transformer is in a preset gear, the output current of the rectifier reaches the active power on the input side of the DC ice-melting device under a preset test current; the rated output capacity of the capacitor bank is that when the output side of the DC ice-melting device is short-circuited and the ice-melting transformer is in a preset gear, the output current of the rectifier reaches the reactive power on the input side of the DC ice-melting device under a preset test current.

9. The high current test system of the DC ice melting device according to claim 6, characterized in that: The DC ice melting device and the test platform are detachably electrically connected via a test cable.

10. A processing device, characterized in that: The invention comprises a processor and a memory, wherein the processor executes the steps of the high current test method for a DC ice melting device as claimed in any one of claims 1 to 5 by calling a program or instruction stored in the memory.

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