Dual-redundancy transformer neutral point direct current magnetic bias suppression device based on self-driving technology

Abstract

The invention provides a transformer neutral point direct current magnetic bias suppression device based on self-driving technology dual redundancy, and relates to the technical field of direct current magnetic bias governance, the device comprises a blocking capacitor, an eddy current self-driving switch, a controller, a temperature sensor and a bypass switch; one end of a self-driven coil in the eddy current self-driven switch is connected with the neutral point of the transformer, the other end of the self-driven coil is connected with one end of a blocking capacitor, and the other end of the blocking capacitor is grounded; movable and static contacts of the eddy current self-driven switch are connected in parallel with the blocking capacitor, and the bypass switch is connected in parallel with the blocking capacitor; the input end of the controller is electrically connected with the output end of the temperature sensor, and the controller is used for controlling the bypass switch to be switched on or switched off so as to respond to the working temperature of the blocking capacitor to control the bypass switch to act. In the process of generating a single-phase short-circuit fault, a large current flows through the eddy current disc of the eddy current self-driven switch, so that the eddy current self-driven switch is closed, the fault current flowing through the blocking capacitor is reduced, and the possibility of damage to the blocking capacitor is further reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of DC bias control, and in particular to a transformer neutral point DC bias suppression device based on self-driving technology and dual redundancy. Background Art

[0002] With the development of high-voltage and ultra-high-voltage direct current (UHVDC) transmission technology in my country, the number of DC projects in operation is increasing. In a DC transmission system operating with a single-stage earth return, current is injected into the earth through the grounding stage, forming a constant DC current field near the stage site. In this situation, the AC substations and power plants located near the DC grounding pole are at different DC potentials. When two AC substations are connected by an AC line and the neutral points of the main transformers at the two stations are directly grounded, the DC potential of the neutral points of the transformers at the two stations differs, resulting in DC magnetic bias.

[0003] Generally speaking, a DC bias suppression device used to control DC bias magnetism includes a DC blocking capacitor, which is connected in series between the neutral point of the transformer and the ground to reduce the impact of the ground potential on the neutral point potential of the transformer, thereby reducing the DC bias magnetism between the transformers.

[0004] However, during a single-phase short-circuit fault, a large fault current will flow through the DC blocking capacitor, which may damage the DC blocking capacitor. At the same time, under long-term working conditions, the DC blocking capacitor may be at a high operating temperature due to its own aging or poor heat dissipation performance. When the load current of the feeder is large, the DC blocking capacitor may be in a high operating temperature state, thereby increasing the possibility of damage to the DC blocking capacitor. Summary of the Invention

[0005] In order to reduce the possibility of damage to the DC blocking capacitor, the present application provides a transformer neutral point DC bias suppression device based on self-driving technology and dual redundancy.

[0006] The present application provides a transformer neutral point DC bias suppression device based on self-driving technology and dual redundancy, which adopts the following technical solutions: A transformer neutral point DC bias suppression device based on self-driven technology and dual redundancy, the device comprising a DC blocking capacitor, an eddy current self-driven switch, a controller, a temperature sensor, and a bypass switch; One end of the self-driving coil in the eddy current self-driven switch is connected to the neutral point of the transformer, the other end of the self-driving coil is connected to one end of the DC blocking capacitor, and the other end of the DC blocking capacitor is grounded; The moving and static contacts of the eddy current self-driven switch are connected in parallel with the DC blocking capacitor, and the bypass switch is connected in parallel with the DC blocking capacitor; The input end of the controller is electrically connected to the output end of the temperature sensor to receive the operating temperature of the DC blocking capacitor. The controller is used to control the bypass switch to be closed or closed to control the bypass switch action in response to the operating temperature of the DC blocking capacitor.

[0007] Optionally, the device further includes a high-energy zinc oxide component, which is connected in parallel to the DC blocking capacitor; the high-energy zinc oxide component includes a zinc oxide resistor and an energy-absorbing fuse, which are connected in series.

[0008] Optionally, the controller is preset with a method for maintaining components in a DC bias magnetization, the method comprising: Acquire current operating data of the DC blocking capacitor in real time, the current operating data including current operating temperature and current operating current, and compare the current operating temperature with a preset operating temperature threshold; If the current operating temperature is greater than the operating temperature threshold, the bypass switch connected in parallel to the DC blocking capacitor is controlled to be closed, and replacement requirement information of the DC blocking capacitor or closing current adjustment information of the bypass switch is generated.

[0009] Optionally, the eddy current self-driven DC bias suppression device is preset with a closing condition working current of the DC blocking capacitor when the bypass switch reaches the closing condition; The generating of the replacement requirement information of the DC blocking capacitor or the closing current adjustment information of the bypass switch includes: Acquire historical operating data of the DC blocking capacitor within a preset historical sampling period before the current moment, and generate an estimated stable operating current upper limit based on the operating temperature threshold and the historical operating data; If the estimated upper limit of the stable operating current is less than or equal to the closing condition operating current of the DC blocking capacitor, generating replacement requirement information of the DC blocking capacitor; If the estimated upper limit of the stable operating current is greater than the closing condition operating current, generating a normal operating peak current of the DC blocking capacitor according to the historical operating data and a preset safe operating temperature of the DC blocking capacitor; Closing current adjustment information of the bypass switch or replacement requirement information of the DC blocking capacitor is generated according to the normal working peak current and the closing condition working current.

[0010] Optionally, the generating, according to the normal operating peak current and the closing condition operating current, the closing current adjustment information of the bypass switch or the replacement requirement information of the DC blocking capacitor includes: If the normal working peak current is less than the closing condition working current, generating replacement requirement information of the DC blocking capacitor; If the normal working peak current is greater than or equal to the closing condition working current, the closing adjustment working current is calculated and generated according to the closing adjustment working current and the preset adjustable amount; If the normal working peak current is greater than or equal to the closing adjustment working current, generating closing current adjustment information of the bypass switch according to the closing adjustment working current; If the normal operating peak current is less than the closing adjustment operating current, replacement requirement information of the DC blocking capacitor is generated.

[0011] Optionally, generating an estimated upper limit of stable operating current according to the operating temperature threshold and the historical operating data includes: Acquire historical ambient temperature information of the DC blocking capacitor, and establish corresponding relationships between a plurality of the historical operating currents and a plurality of the historical ambient temperatures in the historical operating data at the time of data collection; Filtering out a valid ambient temperature peak value according to the historical ambient temperature information of the DC blocking capacitor and a preset valid sampling time; An estimated stable operating current upper limit is generated according to a plurality of target historical operating temperatures and a plurality of target historical operating currents corresponding to the operating temperature threshold and the effective ambient temperature peak.

[0012] Optionally, screening out a valid ambient temperature peak value according to the historical ambient temperature information of the DC blocking capacitor and a preset valid sampling time includes: According to the historical ambient temperature information, the occupation time of each historical ambient temperature within the historical sampling time before the current moment is divided; The plurality of occupancy times are sorted according to the magnitude of the plurality of historical ambient temperatures, and the plurality of occupancy times are compared with the effective sampling time in turn until the target occupancy time is greater than or equal to the limited sampling time, and the historical ambient temperature corresponding to the target occupancy time is taken as the effective ambient temperature peak.

[0013] Optionally, generating the estimated stable operating current upper limit according to the operating temperature threshold and a plurality of target historical operating temperatures and a plurality of target historical operating currents corresponding to the effective ambient temperature peak value includes: Acquire multiple target historical operating temperatures and multiple target historical operating currents corresponding to the effective ambient temperature peak value; Calculating and generating an actual operating current difference corresponding to each target historical operating temperature based on pre-stored theoretical operating data, a plurality of target historical operating temperatures, and a plurality of target historical operating currents, wherein the theoretical operating data includes a plurality of theoretical operating temperatures and corresponding plurality of theoretical operating currents; Calculating and generating a current growth difference variable between two adjacent target historical operating temperatures based on the multiple actual operating current differences; Calculating and generating an estimated current growth difference variable according to the plurality of current growth difference variables and the operating temperature threshold; Calculating and generating an estimated current difference value based on the estimated current growth difference value variable and a plurality of actual operating current differences; An estimated stable operating current upper limit is calculated and generated according to the estimated current difference, the operating current threshold, and the theoretical operating data.

[0014] Optionally, calculating and generating an estimated current growth difference variable based on the plurality of current growth difference variables and the operating temperature threshold includes: Calculating and generating an average unit current growth difference variable at a unit growth temperature based on the plurality of current growth difference variables; An estimated current growth difference variable is generated by calculation according to the estimated operating temperature difference between the operating temperature threshold and the adjacent target historical operating temperature, and the unit growth difference variable.

[0015] In summary, this application includes at least one of the following beneficial technical effects: When a single-phase short-circuit fault occurs, a large current flows through the eddy current disk of the eddy current self-driven switch, causing the eddy current self-driven switch to close, reducing the fault current flowing through the DC blocking capacitor. At the same time, the temperature sensor feeds back the monitored operating temperature of the DC blocking capacitor to the controller. When the controller identifies that the operating temperature of the DC blocking capacitor reaches the operating temperature threshold of the DC blocking capacitor, the controller controls the bypass switch to close, thereby reducing the current flowing through the DC blocking capacitor and further reducing the possibility of damage to the DC blocking capacitor. In this application, by calculating the unit growth difference variable, the possibility of inaccurate collection of some historical data, which leads to large data estimation gaps, is reduced. At the same time, the theoretical working data is used as a reference, and the estimated current difference generated by the unit growth difference variable is calculated to increase the accuracy of the estimated stable working current upper limit. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 This is a circuit diagram of a DC bias suppression device provided in an embodiment of the present application.

[0018] Figure 2 It is a flow chart of a method for maintaining components of a DC bias suppression device provided in an embodiment of the present application.

[0019] Figure 3 This is a flow chart of generating replacement requirement information or closing current adjustment information provided by an embodiment of the present application.

[0020] Figure 4 This is a flow chart of generating an estimated upper limit of a stable operating current provided in an embodiment of the present application.

[0021] Figure 5 This is another flowchart of generating an estimated upper limit of a stable operating current provided in an embodiment of the present application. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the present invention clearer, the following Figure 1-5 The embodiments of the present invention are described in further detail.

[0023] An embodiment of the present application provides a transformer neutral point DC bias suppression device with dual redundancy based on self-driven technology, including a DC blocking capacitor, an eddy current self-driven switch, a controller, a temperature sensor, a bypass switch, and a high-energy zinc oxide component.

[0024] One end of the self-driven coil in the eddy current self-driven switch is connected to the neutral point of the transformer, and the other end is connected to one end of the DC blocking capacitor, the other end of which is grounded. The moving and static contacts of the eddy current self-driven switch are connected in parallel with the DC blocking capacitor, and a temperature sensor is used to monitor the operating temperature of the DC blocking capacitor. A bypass switch is connected in parallel with the DC blocking capacitor. During a single-phase short-circuit fault, a large current flows through the eddy current disc of the eddy current self-driven switch, causing the eddy current self-driven switch to close, reducing the fault current flowing through the DC blocking capacitor.

[0025] The input end of the controller is electrically connected to the output end of the temperature sensor. The temperature sensor feeds back the monitored operating temperature of the DC blocking capacitor to the controller. The control end of the controller is electrically connected to the control end of the bypass switch. When the controller identifies the operating temperature of the DC blocking capacitor and reaches the operating temperature threshold of the DC blocking capacitor, the controller controls the bypass switch to close, thereby reducing the current flowing through the DC blocking capacitor and reducing the possibility of damage to the DC blocking capacitor.

[0026] The high-energy zinc oxide component is connected in parallel with the DC isolation capacitor. The high-energy zinc oxide component includes a zinc oxide resistor and an energy-absorbing fuse, and the zinc oxide resistor and the energy-absorbing fuse are connected in series.

[0027] The controller of the embodiment of the present application is pre-set with a method for maintaining devices in DC bias magnetization. The method is applied to a transformer neutral point DC bias magnetization suppression device with dual redundancy based on self-drive technology. The executor of the method can be the controller in the DC bias magnetization suppression device.

[0028] The following will be combined with specific implementation methods, such as Figure 2 The processing flow shown in the figure is described in detail, and the content can be as follows: Step S101 , obtaining current operating data of the DC blocking capacitor in real time, the current operating data including current operating temperature and current operating current, and comparing the current operating temperature with a preset operating temperature threshold.

[0029] In practice, when the three-phase currents at the transformer neutral point are unequal, a current flows through the transformer neutral point. This can occur, for example, when single-phase loads predominate in residential and commercial power distribution systems, or when nonlinear loads such as inverters, LED power supplies, and UPS generate third-order harmonics. The controller collects data on the DC blocking capacitor's operating status during normal operation to determine and estimate its stable operation.

[0030] The controller obtains the current working data of the DC blocking capacitor in real time, wherein the current working data includes the current working temperature and the current working current.

[0031] The controller then compares the current operating current with the DC blocking capacitor's preset operating temperature threshold. This threshold can be sourced from the capacitor's data sheet or user-defined. If the current operating temperature exceeds the threshold, the blocking capacitor is operating at a high temperature.

[0032] Step S102: If the current operating temperature is greater than the operating temperature threshold, the bypass switch connected in parallel to the DC blocking capacitor is controlled to be closed, and replacement requirement information of the DC blocking capacitor or closing current adjustment information of the bypass switch is generated.

[0033] In implementation, if the controller identifies that the current operating temperature is greater than the operating temperature threshold, the controller controls the bypass switch to close, thereby reducing the current flowing through the DC blocking capacitor, thereby reducing the possibility of damage to the DC blocking capacitor.

[0034] Furthermore, the controller may reduce the possibility of the DC blocking capacitor operating in a high-temperature state again by replacing the DC blocking capacitor or reducing the closing current of the bypass switch.

[0035] Specifically, in step S102, there is also the following Figure 3 The processing shown in the figure is as follows: Step S201 , obtaining historical operating data of the DC blocking capacitor within a preset historical sampling period before the current moment, and generating an estimated upper limit of a stable operating current according to an operating temperature threshold and the historical operating data.

[0036] In implementation, in order to facilitate the acquisition of the correspondence between the working current of the DC blocking capacitor and the closing current of the bypass switch, in this application, the working current corresponding to the DC blocking capacitor when the bypass switch is closed in the DC bias suppression device can be obtained in advance in the laboratory. Here, the working current corresponding to the DC blocking capacitor is called the closing condition working current.

[0037] Then the controller obtains historical operating data of the plurality of DC blocking capacitors within a historical sampling period before the current moment, wherein the historical operating data includes historical operating currents and historical operating temperatures of the DC blocking capacitors.

[0038] The controller then uses the historical operating current and historical operating temperature in the historical operating data to calculate the operating current corresponding to the DC blocking capacitor when the DC blocking capacitor reaches the operating temperature threshold. The operating current corresponding to the DC blocking capacitor here is called the estimated stable operating current upper limit.

[0039] Step S202 : If the estimated upper limit of the stable operating current is less than or equal to the closing condition operating current of the DC blocking capacitor, then generating replacement requirement information of the DC blocking capacitor.

[0040] In implementation, the controller compares the estimated upper limit of stable operating current with the operating current under closing conditions; If the estimated upper limit of the stable operating current is less than or equal to the operating current under the closing condition, it can be understood that when the operating current of the DC blocking capacitor reaches the estimated upper limit of the stable operating current, that is, when the operating temperature of the DC blocking capacitor can reach the operating threshold, the bypass switch does not meet the closing condition. At this time, the controller generates a replacement request information requesting the replacement of the DC blocking capacitor.

[0041] Step S203: If the estimated upper limit of the stable operating current is greater than the operating current under the closing condition, a normal operating peak current of the DC blocking capacitor is generated according to historical operating data and a preset safe operating temperature of the DC blocking capacitor.

[0042] In implementation, the controller compares the estimated upper limit of stable operating current with the operating current under closing conditions; If the estimated upper limit of the stable operating current is greater than the operating current under the closing condition, the controller will use the historical operating current and historical operating temperature in the historical operating data to calculate the operating current corresponding to the DC blocking capacitor when the DC blocking capacitor reaches the safe operating temperature. The operating current corresponding to the DC blocking capacitor here is called the normal operating peak current.

[0043] The safe operating temperature is the temperature at which the DC blocking capacitor can operate in a stable state for a long period of time. This safe operating temperature can be obtained from the DC blocking capacitor's data sheet or set by the user. The safe operating temperature must be lower than the operating temperature threshold, and the normal operating peak current must be lower than the estimated upper limit of the stable operating current.

[0044] Step S204 : generating closing current adjustment information of the bypass switch or replacement requirement information of the DC blocking capacitor according to the normal working peak current and the closing condition working current.

[0045] During implementation, after calculating and generating the normal working peak current, the controller uses the normal working peak current and the closing adjustment working current to determine whether the closing current needs to be adjusted or the closing capacitor needs to be replaced.

[0046] Specifically, in step S204, the following processing is also performed, and the operation flow is as follows: If the normal working peak current is less than the working current under the closing condition, the replacement requirement information of the DC blocking capacitor is generated; If the normal working peak current is greater than or equal to the closing condition working current, the closing adjustment working current is calculated and generated according to the closing adjustment working current and the preset adjustable amount; If the normal working peak current is greater than or equal to the closing adjustment working current, the closing current adjustment information of the bypass switch is generated according to the closing condition working current; If the normal working peak current is less than the closing adjustment working current, the replacement requirement information of the DC blocking capacitor is generated.

[0047] In implementation, the controller first compares the normal operating peak current with the closing condition operating current. The comparison results have the following two situations: Case 1: If the normal operating peak current is lower than the closing condition operating current, a replacement requirement for the DC blocking capacitor is generated. Understandably, in Case 1, when the DC blocking capacitor reaches the normal operating peak current, that is, when the DC blocking capacitor reaches the safe operating temperature, the bypass switch has not yet reached the closing condition, so the DC blocking capacitor needs to be replaced. Case 2: If the normal working peak current is greater than or equal to the closing condition working current, the closing condition working current is subtracted from the preset adjustable amount to calculate the closing adjustment working current; Furthermore, in case 2, the normal working peak current and the closing adjustment working current are compared. The comparison results show the following two situations: Case 2.1: If the normal operating peak current is greater than or equal to the closing adjustment operating current, closing current adjustment information for the bypass switch is generated based on the closing adjustment operating current. It can be understood that by adjusting the closing current of the bypass switch, the bypass switch can be bypassed to achieve closing conditions when the DC blocking capacitor has not reached a safe operating temperature. Case 2.2: If the normal operating peak current is less than the closing adjustment operating current, information on the replacement requirement of the DC blocking capacitor is generated. It is understandable that by adjusting the closing current of the bypass switch, when the DC blocking capacitor reaches the safe operating temperature, the bypass switch still does not meet the closing condition. At this time, the DC blocking capacitor is unable to meet the actual working requirements, so it needs to be replaced.

[0048] Optionally, in step S201, there is also Figure 4 The specific operation process is as follows: Step S301 : acquiring historical ambient temperature information of the DC blocking capacitor, and establishing corresponding relationships between a plurality of historical operating currents and a plurality of historical ambient temperatures in the historical operating data at the time of data collection.

[0049] During implementation, the controller obtains historical ambient temperature information of the DC blocking capacitor within a historical sampling period prior to the current moment. The historical ambient temperature information includes multiple historical ambient temperatures and corresponding data collection times. Furthermore, the controller establishes a correspondence between the multiple historical ambient temperatures and multiple historical operating currents in the historical operating data based on the data collection times, and simultaneously establishes a correspondence between the multiple historical ambient temperatures and multiple historical operating temperatures in the historical operating data.

[0050] Step S302 : Filter out the effective ambient temperature peak value according to the historical ambient temperature information of the DC blocking capacitor and the preset effective sampling time.

[0051] In implementation, the controller calculates the duration of each historical ambient temperature based on multiple historical ambient temperatures in the historical ambient temperature information, and compares the duration with the effective sampling duration to screen out the effective ambient temperature peak.

[0052] Specifically, there are the following processing methods: Based on the historical ambient temperature information, the occupation time of each historical ambient temperature before the current moment within the historical sampling time is divided; The multiple occupancy times are sorted according to the magnitude of the multiple historical ambient temperatures, and the multiple occupancy times are compared with the effective sampling time in turn until the target occupancy time is greater than or equal to the limited sampling time. The historical ambient temperature corresponding to the target occupancy time is taken as the effective ambient temperature peak.

[0053] During implementation, the controller uses the historical ambient temperatures in the historical ambient temperature information to count the existence time of each historical ambient temperature within the historical sampling time before the current moment. The existence time here is called the occupancy time.

[0054] The controller then sorts the occupancy durations from highest to lowest according to their corresponding historical ambient temperatures and compares the sorted occupancy durations with the valid sampling durations. This occupancy duration is considered the target occupancy duration until it reaches a value greater than or equal to the valid sampling duration. The historical ambient temperature corresponding to the target occupancy duration is then used as the peak valid ambient temperature.

[0055] Step S303 : generating an estimated upper limit of a stable operating current according to a plurality of target historical operating temperatures and a plurality of target historical operating currents corresponding to the operating temperature threshold and the effective ambient temperature peak value.

[0056] During implementation, the controller uses multiple historical operating temperatures and multiple historical operating currents corresponding to the effective ambient temperature peak to infer the estimated stable operating current upper limit under the operating temperature threshold. Here, the multiple historical operating temperatures and multiple historical operating currents corresponding to the effective ambient temperature peak are referred to as target historical operating temperatures and target historical operating currents, respectively.

[0057] Specifically, in step S303, there is also the following Figure 5 The processing shown in the figure is as follows: Step S401 : obtaining a plurality of target historical operating temperatures and a plurality of target historical operating currents corresponding to effective ambient temperature peak values.

[0058] During implementation, the controller first matches multiple target historical operating temperatures and target historical operating currents corresponding to the effective ambient temperature peak values ​​from the historical operating data.

[0059] Step S402, based on pre-stored theoretical operating data, multiple target historical operating temperatures and multiple target historical operating currents, calculate and generate the actual operating current difference corresponding to each target historical operating temperature, where the theoretical operating data includes multiple theoretical operating temperatures and corresponding multiple theoretical operating currents.

[0060] In implementation, the controller pre-stores theoretical working data of the DC bias magnetic device, and the theoretical working data refers to working data of the DC blocking capacitor measured under a constant temperature condition of 25° C. in a laboratory.

[0061] The controller will match the corresponding theoretical operating current and theoretical operating temperature in the theoretical operating data with each target historical operating current, and then calculate and generate multiple actual operating current difference values ​​by subtracting the target historical operating temperature corresponding to the target historical operating current from the theoretical operating temperature.

[0062] Step S403 : calculating and generating a current growth difference variable between two adjacent target historical operating temperatures based on the multiple actual operating current differences.

[0063] In implementation, the controller sorts multiple actual operating current differences according to the size of the historical operating temperature, and then calculates the difference between the actual operating current differences corresponding to two adjacent historical operating temperatures, which is called the current growth difference variable.

[0064] Step S404 : calculating and generating an estimated current growth difference variable based on the multiple current growth difference variables and the operating temperature threshold.

[0065] In implementation, the controller first selects an adjacent target historical operating temperature that is closest to the operating temperature threshold from a plurality of target historical operating temperatures.

[0066] Then, a current growth difference variable between the adjacent target historical operating temperature and the operating temperature threshold is calculated through multiple current growth difference variables, which is referred to as an estimated current growth difference variable.

[0067] Specifically, the processing flow of step S204 is as follows: Calculating and generating an average unit current growth difference variable at a unit growth temperature based on a plurality of current growth difference variables; An estimated current growth difference variable is calculated based on an estimated operating temperature difference between the operating temperature threshold and an adjacent target historical operating temperature and a unit growth difference variable.

[0068] In implementation, the controller calculates and generates an average unit current increase difference variable at a unit increase temperature based on a temperature difference between two adjacent target historical operating temperatures and a current increase variable.

[0069] Then, the operating temperature threshold is subtracted from the historical operating temperature of the adjacent target to calculate the estimated operating temperature difference, and then the estimated temperature difference is multiplied by the unit growth difference variable to calculate the estimated current growth difference variable.

[0070] Step S405 , calculating and generating an estimated current difference value based on the estimated current growth difference value variable and a plurality of actual operating current differences.

[0071] In implementation, the controller adds the estimated current growth difference variable and the actual operating current difference corresponding to the adjacent target historical operating temperature to calculate and generate the estimated current difference.

[0072] Step S406 , calculating and generating an estimated upper limit of the stable operating current according to the estimated current difference, the operating current threshold, and the theoretical operating data.

[0073] During implementation, the controller matches the theoretical working current corresponding to the working current threshold in the theoretical working data, and then adds the estimated current difference and the theoretical working current to calculate and generate the estimated working current upper limit.

[0074] In this application, by calculating the unit growth difference variable, the possibility of inaccurate collection of some historical data, which leads to large data estimation gaps, is reduced. At the same time, the theoretical working data is used as a reference, and the estimated current difference generated by the unit growth difference variable is calculated to increase the accuracy of the estimated stable working current upper limit.

[0075] The controllers provided in the embodiments of the present application may vary significantly due to different configurations or performance, and may include one or more central processing units (e.g., one or more processors) and memories, and one or more storage media (e.g., one or more mass storage devices) for storing applications or data. The memories and storage media may be either transient or persistent. The program stored on the storage medium may include one or more modules (not shown in the figure), each of which may include a series of instruction operations on the controller.

[0076] The controller may also include one or more power supplies, one or more wired or wireless network interfaces, one or more input and output interfaces, one or more keyboards, and / or one or more operating systems.

[0077] The controller may include a memory and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by one or more processors to perform the processing of the controller.

[0078] Those skilled in the art will understand that all or part of the steps to implement the above embodiments may be accomplished by hardware, or may be accomplished by instructing the relevant hardware through a program, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, etc.

[0079] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

[0080] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A transformer neutral point DC bias suppression device based on self-driven dual redundancy technology, characterized by: The device includes a DC blocking capacitor, an eddy current self-driven switch, a controller, a temperature sensor and a bypass switch; One end of the self-driving coil in the eddy current self-driven switch is connected to the neutral point of the transformer, the other end of the self-driving coil is connected to one end of the DC blocking capacitor, and the other end of the DC blocking capacitor is grounded; The moving and static contacts of the eddy current self-driven switch are connected in parallel with the DC blocking capacitor, and the bypass switch is connected in parallel with the DC blocking capacitor; The input end of the controller is electrically connected to the output end of the temperature sensor to receive the operating temperature of the DC blocking capacitor. The controller is used to control the bypass switch to be closed or closed to control the bypass switch action in response to the operating temperature of the DC blocking capacitor.

2. The device according to claim 1, characterized in that: The device further comprises a high-energy zinc oxide component, which is connected in parallel to the DC blocking capacitor; the high-energy zinc oxide component comprises a zinc oxide resistor and an energy-absorbing fuse, which are connected in series.

3. The device according to claim 1, characterized in that The controller is pre-set with a method for maintaining components in DC bias magnetization, the method comprising: Acquire current operating data of the DC blocking capacitor in real time, the current operating data including current operating temperature and current operating current, and compare the current operating temperature with a preset operating temperature threshold; If the current operating temperature is greater than the operating temperature threshold, the bypass switch connected in parallel to the DC blocking capacitor is controlled to be closed, and replacement requirement information of the DC blocking capacitor or closing current adjustment information of the bypass switch is generated.

4. The method according to claim 3, characterized in that The eddy current self-driven DC bias suppression device is preset with a closing condition working current of the DC blocking capacitor when the bypass switch reaches the closing condition; The generating of the replacement requirement information of the DC blocking capacitor or the closing current adjustment information of the bypass switch includes: Acquire historical operating data of the DC blocking capacitor within a preset historical sampling period before the current moment, and generate an estimated stable operating current upper limit based on the operating temperature threshold and the historical operating data; If the estimated upper limit of the stable operating current is less than or equal to the closing condition operating current of the DC blocking capacitor, generating replacement requirement information of the DC blocking capacitor; If the estimated upper limit of the stable operating current is greater than the closing condition operating current, generating a normal operating peak current of the DC blocking capacitor according to the historical operating data and a preset safe operating temperature of the DC blocking capacitor; Closing current adjustment information of the bypass switch or replacement requirement information of the DC blocking capacitor is generated according to the normal working peak current and the closing condition working current.

5. The method according to claim 4, characterized in that The generating, according to the normal working peak current and the closing condition working current, the closing current adjustment information of the bypass switch or the replacement requirement information of the DC blocking capacitor includes: If the normal working peak current is less than the closing condition working current, generating replacement requirement information of the DC blocking capacitor; If the normal working peak current is greater than or equal to the closing condition working current, the closing adjustment working current is calculated and generated according to the closing adjustment working current and the preset adjustable amount; If the normal working peak current is greater than or equal to the closing adjustment working current, generating closing current adjustment information of the bypass switch according to the closing adjustment working current; If the normal working peak current is less than the closing adjustment working current, replacement requirement information of the DC blocking capacitor is generated.

6. The method according to claim 4, characterized in that The generating, according to the operating temperature threshold and the historical operating data, an estimated upper limit of the stable operating current includes: Acquire historical ambient temperature information of the DC blocking capacitor, and establish corresponding relationships between a plurality of the historical operating currents and a plurality of the historical ambient temperatures in the historical operating data at the time of data collection; Filtering out a valid ambient temperature peak value according to the historical ambient temperature information of the DC blocking capacitor and a preset valid sampling time; An estimated stable operating current upper limit is generated according to a plurality of target historical operating temperatures and a plurality of target historical operating currents corresponding to the operating temperature threshold and the effective ambient temperature peak.

7. The method according to claim 6, characterized in that The filtering out of the effective ambient temperature peak value according to the historical ambient temperature information of the DC blocking capacitor and a preset effective sampling time includes: According to the historical ambient temperature information, the occupation time of each historical ambient temperature within the historical sampling time before the current moment is divided; The plurality of occupancy times are sorted according to the magnitude of the plurality of historical ambient temperatures, and the plurality of occupancy times are compared with the effective sampling time in turn until the target occupancy time is greater than or equal to the limited sampling time, and the historical ambient temperature corresponding to the target occupancy time is taken as the effective ambient temperature peak.

8. The method according to claim 7, characterized in that The generating of the estimated stable operating current upper limit according to the operating temperature threshold and the multiple target historical operating temperatures and multiple target historical operating currents corresponding to the effective ambient temperature peak value includes: Acquire multiple target historical operating temperatures and multiple target historical operating currents corresponding to the effective ambient temperature peak value; Calculating and generating an actual operating current difference corresponding to each target historical operating temperature based on pre-stored theoretical operating data, a plurality of target historical operating temperatures, and a plurality of target historical operating currents, wherein the theoretical operating data includes a plurality of theoretical operating temperatures and corresponding plurality of theoretical operating currents; Calculating and generating a current growth difference variable between two adjacent target historical operating temperatures based on the multiple actual operating current differences; Calculating and generating an estimated current growth difference variable according to the plurality of current growth difference variables and the operating temperature threshold; Calculating and generating an estimated current difference value based on the estimated current growth difference value variable and a plurality of actual operating current differences; An estimated stable operating current upper limit is calculated and generated according to the estimated current difference, the operating current threshold, and the theoretical operating data.

9. The method according to claim 8, characterized in that The step of calculating and generating an estimated current growth difference variable based on the plurality of current growth difference variables and the operating temperature threshold comprises: Calculating and generating an average unit current growth difference variable at a unit growth temperature based on the plurality of current growth difference variables; An estimated current growth difference variable is generated by calculation according to the estimated operating temperature difference between the operating temperature threshold and the adjacent target historical operating temperature, and the unit growth difference variable.

Images