Extra-high-voltage direct-current online valve group withdrawing method and system capable of self-adapting to trigger angle change

Abstract

The invention provides an ultra-high voltage direct current on-line valve group withdrawing method and system capable of self-adapting to trigger angle change, and the method comprises the steps: responding to a single valve group locking instruction; the inverter station sends a locking execution instruction to the rectifier station and configures the integral duration of an inverter-side trigger angle limiter and a delay locking execution moment according to an inverter-side steady-state trigger angle, an alternating-current voltage fluctuation ratio, an alternating-current frequency deviation and inter-station communication time delay; when the delay locking execution moment is reached, executing an inverter side locking process which comprises the step of adaptively adjusting the trigger angle movement rate based on the integral duration of an inverter side trigger angle limiter; and according to the rectification-side steady-state trigger angle and the direct current change rate, the rectification-side trigger angle limiter integral duration is configured, and a rectification-side locking process including self-adaptive adjustment of the trigger angle movement rate based on the rectification-side trigger angle limiter integral duration is executed immediately. According to the invention, disturbance of the online valve withdrawing group to the system can be reduced, and the operation stability of an AC-DC power grid is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of ultra-high voltage direct current (UHV DC) power transmission, and in particular to an ultra-high voltage direct current (UHV DC) online valve group withdrawal method and system with adaptive trigger angle change. Background Art

[0002] The UHV DC converter station is equipped with a double valve group on a single pole. When the double valve group is unlocked and running, one of the valve groups can be allowed to be withdrawn online. Under normal circumstances, the online exit process of the converter is as follows: after the valve group withdrawal command is issued, the trigger angle ALPHA_90 command (the locking timing command to move the trigger angle to 90°) is sent to the converter to be withdrawn, so that the voltage across the converter is zero; then the bypass pair is put into operation, and the bypass circuit breaker BPS (Bidirectional Power Switch) is closed to reduce the current flowing through the converter to zero; finally, the trigger pulse of the converter to be withdrawn is blocked. The specific online exit process of the converter is as follows: Figure 1 As shown, the inverter side converter is exited first, and then the rectifier side converter is exited to ensure that the inverter side voltage is not higher than the rectifier side during the online exit of the converter, and does not affect the current transmission of the operating converter valve.

[0003] However, when the existing UHV DC is withdrawn online, both the rectifier side and the inverter side simultaneously execute the command of moving the trigger angle to 90° at a fixed rate. However, the starting trigger angles of the rectifier side and the inverter side in actual operation are not consistent (the trigger angle operating range of the rectifier side is 12.5°~17.5°, and the arc extinction angle operating range of the inverter side is 17.5°~21.5°), which will lead to inconsistent time for the trigger angles on both sides to move to 90°; in addition, the redundant communication loop mechanism and communication delay problem adopted between stations will also lead to inconsistent starting time for the rectifier side and the inverter side to start executing the trigger angle movement command. That is, the existing UHV online valve group withdrawal method will lead to different trigger angle change rates on the rectifier side and the inverter side, which will cause inconsistent voltage changes in the two stations, which will not only cause a large disturbance to the DC current, but also affect the stability of the DC voltage and current when the bypass is turned on. Summary of the invention

[0004] The purpose of the present invention is to provide an ultra-high voltage direct current online valve group withdrawal method with adaptive trigger angle change, by combining the execution time alignment mechanism of the valve group locking instructions on both sides that delays the execution time of the trigger angle shift on the inverter side based on the inter-station communication delay with the adaptive synchronous trigger angle change mechanism that adaptively and reasonably configures the integral time length of the trigger angle limiter on the inverter side and the rectifier side based on the real-time operation conditions of the ultra-high voltage direct current transmission system and the alternating current system, so that when the valve group locking instruction is actually executed, the shift angle starting time of the rectifier side and the inverter side can be effectively aligned and the consistency of the time length for the shift angle on both sides to 90° can be ensured, so as to realize the adaptive synchronization of the trigger angle changes on both sides, effectively reduce the disturbance caused to the DC system by the valve group withdrawal during operation, and thus improve the operation stability of the AC and DC power grids.

[0005] In order to achieve the above-mentioned purpose, a method and system for online valve group withdrawal of ultra-high voltage direct current with adaptive trigger angle change are provided.

[0006] In a first aspect, an embodiment of the present invention provides a method for online valve group withdrawal of ultra-high voltage direct current with adaptive trigger angle change, the method comprising the following steps: In response to the single valve group locking instruction, the inverter station sends a locking execution instruction to the corresponding rectifier station, and configures the inverter side trigger angle limiter integration time and the delayed locking execution time according to the acquired inverter side steady-state trigger angle, AC voltage fluctuation rate, AC frequency deviation and inter-station communication delay, and executes the inverter side locking process when the delayed locking execution time is reached; the inverter side locking process includes adaptively adjusting the trigger angle movement rate based on the inverter side trigger angle limiter integration time; When the rectifier station receives the locking execution instruction, it configures the integration time of the trigger angle limiter on the rectifier side according to the acquired steady-state trigger angle and DC current change rate on the rectifier side, and immediately executes the locking process on the rectifier side; the locking process on the rectifier side includes adaptively adjusting the trigger angle movement rate based on the integration time of the trigger angle limiter on the rectifier side.

[0007] Further, the step of configuring the inverter side trigger angle limiter integration time and delayed locking execution time according to the acquired inverter side steady-state trigger angle, AC voltage fluctuation rate, AC frequency deviation and inter-station communication delay includes: According to the inverter-side steady-state trigger angle, the AC voltage fluctuation rate and the AC frequency deviation, the preset target angle movement time is adjusted to obtain a first integration time, and the first integration time is configured as an integration time constant in the corresponding inverter-side trigger angle limiter; The delayed locking execution time is obtained according to the sum of the inter-station communication delay and the receiving time corresponding to the single valve group locking instruction.

[0008] Further, the first integration time is expressed as: In the formula, Indicates the duration of the first integral; Indicates the duration of the preset target angle movement; and represents a constant coefficient; and They represent the AC voltage fluctuation rate and AC frequency deviation respectively; Indicates the steady-state trigger angle of the inverter side.

[0009] Furthermore, the step of configuring the integral time length of the rectifier side trigger angle limiter according to the acquired rectifier side steady-state trigger angle and DC current change rate includes: According to the rectifier-side steady-state trigger angle and the DC current change rate, the preset target angle movement duration is adjusted to obtain a second integration duration, and the second integration duration is configured at the corresponding rectifier-side trigger angle limiter.

[0010] Further, the second integration time is expressed as: In the formula, Indicates the duration of the second integral; Indicates the duration of the preset target angle movement; represents a constant coefficient; Indicates the rate of change of DC current; Indicates the steady-state firing angle on the rectifier side.

[0011] Furthermore, the method further comprises: The inverter station periodically monitors the path communication delays of different communication paths with the rectifier station, obtains the minimum path communication delay within the monitoring period, switches the current inter-station communication path to the communication path corresponding to the minimum path communication delay, and updates the inter-station communication delay record according to the minimum path communication delay.

[0012] Furthermore, the inverter station periodically monitors the path communication delays of different communication paths with the rectifier station, and the step of obtaining the minimum path communication delay within the monitoring period includes: Periodically generate a path detection signal corresponding to each communication path based on a preset time interval, and simultaneously send the path detection signal to the rectifier station through the corresponding communication path; the path detection signal includes a path identifier and a sending time; Receiving the path detection response signal returned by the rectifier station through each communication path, and obtaining the corresponding path communication delay according to the receiving time of the path detection response signal and the response signal data; the response signal data includes the path identifier and the sending time in the corresponding path detection signal; According to the minimum value of the path communication delays of all communication paths, the minimum path communication delay within the monitoring period is obtained.

[0013] In a second aspect, an embodiment of the present invention provides an ultra-high voltage direct current online valve group withdrawal system with adaptive trigger angle change, the system comprising: The inverter station control module is used to respond to the single valve group locking instruction, send a locking execution instruction to the corresponding rectifier station, and configure the inverter side trigger angle limiter integration time and delayed locking execution time according to the acquired inverter side steady-state trigger angle, AC voltage fluctuation rate, AC frequency deviation and inter-station communication delay, and execute the inverter side locking process when the delayed locking execution time is reached; the inverter side locking process includes adaptively adjusting the trigger angle movement rate based on the inverter side trigger angle limiter integration time; The rectifier station control module is used to configure the integration time of the rectifier side trigger angle limiter according to the acquired steady-state trigger angle and DC current change rate of the rectifier side when receiving the lockout execution instruction, and immediately execute the rectifier side lockout process; the rectifier side lockout process includes adaptively adjusting the trigger angle movement rate based on the integration time of the rectifier side trigger angle limiter.

[0014] Furthermore, the inverter station control module is also used to periodically monitor the path communication delays of different communication paths between the rectifier stations, obtain the minimum path communication delay within the monitoring period, and switch the current inter-station communication path to the communication path corresponding to the minimum path communication delay, and update the inter-station communication delay record according to the minimum path communication delay; The rectifier station control module is also used to receive the path detection signal sent by the inverter station through different communication paths, generate a corresponding path detection response signal according to the path detection signal, and send the path detection response signal to the inverter station through the corresponding communication path.

[0015] Furthermore, the periodic monitoring of the path communication delays of different communication paths between the rectifier stations to obtain the minimum path communication delay within the monitoring period includes: Periodically generate a path detection signal corresponding to each communication path based on a preset time interval, and simultaneously send the path detection signal to the rectifier station through the corresponding communication path; the path detection signal includes a path identifier and a sending time; Receiving the path detection response signal returned by the rectifier station through each communication path, and obtaining the corresponding path communication delay according to the receiving time of the path detection response signal and the response signal data; the response signal data includes the path identifier and the sending time in the corresponding path detection signal; According to the minimum value of the path communication delays of all communication paths, the minimum path communication delay within the monitoring period is obtained.

[0016] The present invention provides an ultra-high voltage direct current online valve group withdrawal method and system with adaptive trigger angle change. The method realizes that in response to a single valve group locking instruction, an inverter station sends a locking execution instruction to a corresponding rectifier station, and configures the inverter side trigger angle limiter integration time and the delayed locking execution time according to the acquired inverter side steady-state trigger angle, AC voltage fluctuation rate, AC frequency deviation and station-to-station communication delay. When the delayed locking execution time is reached, the inverter side locking process including adaptively adjusting the trigger angle moving rate based on the inverter side trigger angle limiter integration time is executed, and when the rectifier station receives the locking execution instruction, the rectifier side trigger angle limiter integration time is configured according to the acquired rectifier side steady-state trigger angle and DC current change rate, and the rectifier side locking process including adaptively adjusting the trigger angle moving rate based on the rectifier side trigger angle limiter integration time is immediately executed. Compared with the prior art, the method for online valve group withdrawal of UHV DC with adaptive trigger angle change combines the execution time alignment mechanism of the valve group locking instructions on both sides that delays the execution time of the shifting trigger angle on the inverter side based on the inter-station communication delay with the adaptive synchronous trigger angle change mechanism that adaptively and reasonably configures the integral time length of the trigger angle limiter on the inverter side and the rectifier side based on the real-time operation conditions of the UHV DC transmission system and the AC system. When the valve group locking instruction is actually executed, the shift angle starting time of the rectifier side and the inverter side can be effectively aligned and the consistency of the time length for the shift angle on both sides to 90° can be ensured, so as to realize the adaptive synchronization of the trigger angle changes on both sides, effectively reduce the disturbance caused by the valve group withdrawal during operation to the DC system, and thus improve the operation stability of the AC and DC power grids. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the converter online withdrawal process in the existing UHV DC online valve group withdrawal method; Figure 2 It is a flow chart of a method for online valve group withdrawal of ultra-high voltage direct current with adaptive trigger angle change in an embodiment of the present invention; Figure 3 It is a schematic diagram of the converter online withdrawal process in the UHV DC online valve group withdrawal method with adaptive trigger angle change in an embodiment of the present invention; Figure 4 It is a structural schematic diagram of an ultra-high voltage direct current online valve withdrawal system with adaptive trigger angle change in an embodiment of the present invention. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and beneficial effects of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. Obviously, the embodiments described below are part of the embodiments of the present invention and are only used to illustrate the present invention, but are not used to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] The method for online valve group withdrawal of ultra-high voltage direct current with adaptive trigger angle change provided by the present invention can be understood as a method for withdrawing the valve group of ultra-high voltage direct current with adaptive trigger angle change, which is based on the current application status that when withdrawing the valve group of ultra-high voltage direct current with adaptive trigger angle change, the direct current system is disturbed due to the inconsistent execution command time and trigger angle change rate between the rectifier side and the inverter side, which affects the operation stability of the AC and DC power grid. The method can solve the problems of inconsistent execution command time and trigger angle change rate between the rectifier side and the inverter side at the same time, so as to achieve an online valve group withdrawal scheme with adaptive synchronization of trigger angle changes on both sides. The following embodiments will explain the method for online valve group withdrawal of ultra-high voltage direct current with adaptive trigger angle change of the present invention in detail.

[0020] In one embodiment, Figure 2 As shown, a method for online valve group withdrawal of ultra-high voltage direct current with adaptive trigger angle change is provided, comprising the following steps: S11. In response to the single valve group locking instruction, the inverter station sends a locking execution instruction to the corresponding rectifier station, and configures the inverter side trigger angle limiter integration time and the delayed locking execution time according to the acquired inverter side steady-state trigger angle, AC voltage fluctuation rate, AC frequency deviation and inter-station communication delay, and executes the inverter side locking process when the delayed locking execution time is reached; the inverter side locking process includes adaptively adjusting the trigger angle movement rate based on the inverter side trigger angle limiter integration time; wherein, the single valve group locking instruction can be understood as a single valve group online exit instruction issued by the corresponding control system in the UHV DC transmission system based on the actual system operation status, which will not be repeated here.

[0021] exist Figure 1In the actual converter online exit process shown in the figure, when the inverter station receives the single valve group locking instruction and starts to execute it, it will simultaneously send a message to the rectifier station that it has executed the locking. Then, after the rectifier station confirms that the locking has been executed on the station, it starts to execute the locking process of its own station. However, considering that there will inevitably be communication delays in the inter-station communication between the inverter station and the rectifier station in the actual system operation, the deviation between the starting time of the rectifier station executing the locking process and the starting time of the inverter executing the locking process is too large, which will cause a large difference in the movement of the trigger angles of the two stations when the locking process is executed on both sides, thereby causing a large disturbance to the DC voltage and DC current. In order to align the starting time of the execution of the locking instruction by the two stations as much as possible, this embodiment preferably sets the communication delay between the inverter station and the rectifier station obtained based on the monitoring. The signal delay delays the start time of the inverter station executing the locking process; at the same time, considering that the steady-state trigger angles on both sides of the rectifier station and the inverter station are not consistent in actual system operation, if the same ALPHA_90 execution rate is directly set on both sides, the actual time for the angle to move to 90° on both sides may also be inconsistent. In order to ensure that when the rectifier station and the inverter station start to execute the locking process at the same time, the actual time for the angle to move to 90° on both sides is as consistent as possible, this embodiment preferably optimizes the integral time of the trigger angle limiter on the inverter station side based on the interaction between the actual UHV DC transmission system and the AC system, so as to limit the total time for the inverter station to move from the current steady-state trigger angle to the trigger angle target value of 90°.

[0022] In this embodiment, the steady-state trigger angle on the inverter side can be understood as the trigger angle value when the inverter station is running when receiving the single valve group locking command; the corresponding AC voltage fluctuation rate and AC frequency deviation can be understood as the voltage fluctuation and frequency deviation in the AC system that interacts with the ultra-high voltage direct current transmission system. The specific data acquisition can be obtained by deploying corresponding measurement equipment for measurement and analysis or based on the analysis of relevant data collected in the existing monitoring system, which is not specifically limited here. The corresponding inter-station communication delay can be understood as the duration of a round-trip communication between the inverter station and the rectifier station, which can be obtained by configuring the corresponding communication delay detection logic at the inverter end. Specifically, the steps of configuring the integral duration of the inverter side trigger angle limiter and the delayed locking execution time according to the acquired steady-state trigger angle on the inverter side, AC voltage fluctuation rate, AC frequency deviation and inter-station communication delay include: According to the steady-state trigger angle on the inverter side, the AC voltage fluctuation rate and the AC frequency deviation, the preset target angle moving time is adjusted to obtain a first integral time, and the first integral time is configured as an integral time constant on the corresponding inverter side trigger angle limiter; wherein, the preset target angle moving time can be understood as the expected time to move from the stable trigger angle to 90°, which is pre-set according to actual application requirements and is not specifically limited here.

[0023] Taking into account that in actual applications, AC system voltage fluctuations may cause DC system transmission power fluctuations and AC system frequency deviations may cause output deviations of transmission machinery, thereby affecting the stable operation of the DC system. In order to maintain the stability of the coordinated operation of the AC and DC power grids, this embodiment preferably considers the influence of the AC voltage fluctuation rate and the AC frequency deviation on the trigger angle adjustment when executing the trigger angle movement to determine the estimated execution time of the inverter side moving from the stable trigger angle to 90°, so that the trigger angle adjustment of the inverter side is more accurate and reliable; specifically, the first integral time is expressed as: In the formula, Indicates the duration of the first integral; Indicates the preset target angle movement time, which can be set according to actual application requirements; and It represents the constant coefficient, which can be set according to actual application requirements and is not specifically limited here; and They represent the AC voltage fluctuation rate and AC frequency deviation respectively.

[0024] In this embodiment, the integral time constant value of the inverter-side trigger angle limiter is designed by adjusting the preset target angle movement time based on the actual steady-state trigger angle, taking into account the close interactive influence between the UHV DC transmission system and the AC system. This can not only achieve reasonable control of the inverter station trigger angle movement time based on the preset target angle movement time, but also take into account the maintenance of stable operation and power output of the AC and DC power grids.

[0025] The delayed locking execution time is obtained by adding the inter-station communication delay and the receiving time corresponding to the single valve group locking instruction; that is, Figure 3 As shown, the time obtained by delaying the reception time corresponding to the single valve group locking instruction by a time length corresponding to the inter-station communication delay is used as the execution time of the inverter side starting the inverter side locking process.

[0026] S12. When the rectifier station receives the locking execution instruction, it configures the integration time of the trigger angle limiter on the rectifier side according to the acquired steady-state trigger angle and DC current change rate on the rectifier side, and immediately executes the locking process on the rectifier side; the locking process on the rectifier side includes adaptively adjusting the trigger angle movement rate based on the integration time of the trigger angle limiter on the rectifier side.

[0027] like Figure 1As shown, after the rectifier station side receives the message sent by the inverter station side that the locking has been executed, it will start to execute the locking process of this station. In order to ensure that the time for the actual angle shift to 90° is consistent with the inverter station side as much as possible, this embodiment preferably optimizes the integral time of the trigger angle limiter on the inverter station side based on the actual operating status of the ultra-high voltage direct current transmission system, so as to limit the total time for the rectifier station to move from the current steady-state trigger angle to the trigger angle target value of 90°.

[0028] In this embodiment, the steady-state trigger angle on the rectifier side can be understood as the trigger angle value when the rectifier station is running when receiving the single valve group locking command; the corresponding DC current change rate can be understood as the DC current change of the ultra-high voltage DC transmission system. The specific data acquisition can also be obtained by deploying corresponding measurement equipment for measurement and analysis or based on the analysis of relevant data collected in the existing monitoring system, which is not specifically limited here. Specifically, the steps of configuring the integral time length of the trigger angle limiter on the rectifier side according to the acquired steady-state trigger angle and DC current change rate of the rectifier side include: According to the steady-state trigger angle on the rectifier side and the rate of change of the DC current, the preset target angle movement time is adjusted to obtain a second integral time, and the second integral time is configured at the corresponding rectifier side trigger angle limiter; wherein, the preset target angle movement time can be understood as being pre-set according to actual application requirements, and the expected time from the stable trigger angle to 90° needs to be consistent with the preset target angle movement time used on the inverter side.

[0029] Taking into account that in practical applications, the DC current change rate directly reflects whether the operating state of the UHV DC transmission system is stable. For example, if the DC current change rate is large, it is necessary to appropriately speed up the trigger angle adjustment rate to reach the system stable state faster. In order to maintain the stable operation and power output of the DC system, this embodiment preferably considers the influence of the DC current change rate on the trigger angle adjustment when executing the trigger angle movement to determine the estimated execution time of the rectifier side moving from the stable trigger angle to 90°, so that the trigger angle adjustment of the rectifier side is more accurate and reliable; specifically, the second integral time is expressed as: In the formula, Indicates the duration of the second integral; Indicates the duration of the preset target angle movement; represents a constant coefficient; Indicates the rate of change of DC current; Indicates the steady-state firing angle on the rectifier side.

[0030] In this embodiment, the integral time constant value of the rectifier-side trigger angle limiter is designed in a manner that adjusts the preset target angle moving time based on the actual steady-state trigger angle, while taking into account the operating status of the UHV DC transmission system. This not only enables reasonable control of the inverter station trigger angle moving time based on the preset target angle moving time, but also allows for stable and reliable operation of the DC system.

[0031] In response to a single valve group locking instruction provided by an embodiment of the present invention, an inverter station sends a locking execution instruction to a corresponding rectifier station, and configures the inverter side trigger angle limiter integral time and delayed locking execution time according to the acquired inverter side steady-state trigger angle, AC voltage fluctuation rate, AC frequency deviation and inter-station communication delay. When the delayed locking execution time is reached, an inverter side locking process of adaptively adjusting the trigger angle movement rate based on the inverter side trigger angle limiter integral time is executed, and when the rectifier station receives the locking execution instruction, the rectifier station adjusts the trigger angle movement rate based on the acquired rectifier side steady-state trigger angle and The technical solution of configuring the integral time of the trigger angle limiter on the rectifier side according to the DC current change rate and immediately executing the rectifier side locking process including adaptively adjusting the trigger angle moving rate based on the integral time of the trigger angle limiter on the rectifier side can effectively solve the problems of inconsistent execution command time and inconsistent trigger angle change rate between the rectifier side and the inverter side when the existing UHV line valve group is withdrawn, and can ensure the consistency of the start and end time of the execution of the ALPHA_90 instruction on the rectifier side and the inverter side, reduce the disturbance caused by the withdrawal of the valve group on the DC system during operation, and effectively improve the operation stability of the AC and DC power grids.

[0032] In principle, the method of detecting the communication delay between the inverter station and the rectifier station can be implemented by using the relevant existing technology. However, considering that the redundant communication loop mechanism between the inverter station and the rectifier station only realizes the communication fault protection strategy of switching to the backup path when the main communication path fails, in actual application, the problem of reducing the transmission and execution efficiency of the valve group locking instruction due to the large communication delay of the communication path in use may occur. In order to ensure the consistency of the start and end times of the instruction to effectively align the trigger angle to 90° on the rectifier side and the inverter side, and effectively improve the execution efficiency of the valve group withdrawal, this embodiment preferably adopts a multi-path fusion delay detection and path switching mechanism on the inverter station side, and The station can use redundant communication paths based on optical fiber, microwave and power line carrier as carriers. The communication equipment on both sides configures corresponding communication parameters (such as bandwidth, frequency, modulation mode, etc.), priority and corresponding hardware communication interface for each communication path, and is equipped with corresponding optical fiber interface modules, microwave transceiver modules and power line carrier communication modules, etc., which can realize signal modulation, demodulation, encoding and decoding functions and do not interfere with each other. Independent signal processing modules, and based on the different communication delays of different communication paths in actual application scenarios, the path with the smallest communication delay is selected as the instruction transmission path to maximize the communication efficiency in actual applications. Specifically, the method also includes: The inverter station periodically monitors the path communication delays of different communication paths with the rectifier station, obtains the minimum path communication delay within the monitoring period, switches the current inter-station communication path to the communication path corresponding to the minimum path communication delay, and updates the inter-station communication delay record according to the minimum path communication delay; wherein, the period of the inverter station monitoring the path communication delay of each communication path between the rectifier station can be set based on the stability of each communication path in actual application. For example, for a relatively stable situation, a longer time can be set to trigger a delay monitoring, and vice versa, a shorter time can be set to trigger a monitoring. The minimum path communication delay obtained from each periodic monitoring can be used as a condition for the inverter station to select the optimal communication path and switch the communication path with the rectifier station, and can also be used as a basis for setting the delayed locking execution time when it receives a single valve group locking instruction.

[0033] In order to ensure the reliability of obtaining the minimum path communication delay and the optimal communication path between the inverter station and the rectifier station, in this embodiment, a unique path identifier is preferably set for each communication path on the inverter station side. The path identifier can be set to a coding sequence including a timestamp, a random number and a communication protocol. In practical applications, a corresponding path identifier can be generated for each communication path based on a programmable logic device (such as FPGA) or other technology that can implement this function, so as to accurately statistically analyze the communication delay of different communication paths; specifically, the inverter station periodically monitors the path communication delay of different communication paths with the rectifier station, and the step of obtaining the minimum path communication delay within the monitoring period includes: A path detection signal corresponding to each communication path is periodically generated based on a preset time interval, and the path detection signal is simultaneously sent to the rectifier station through the corresponding communication path; the path detection signal includes a path identifier and a sending time, and other information can be added according to actual application requirements; in actual applications, the path identifier in the path detection signal can be embedded in the corresponding detection signal by calling a corresponding path identifier generation module (such as a hardware circuit) to generate a unique identifier, and then the signal is modulated and encoded based on application requirements to adapt to the transmission requirements of the corresponding communication path. For example, for an optical fiber communication path, optical modulation technology is used to load the signal onto an optical carrier, and radio frequency modulation is performed on a microwave communication path.

[0034] Receive the path detection response signal returned by the rectifier station through each communication path, and obtain the corresponding path communication delay according to the receiving time of the path detection response signal and the response signal data; wherein, the path detection response signal can be understood as the path detection signal sent by the inverter station through each communication path received by the rectifier station, and the response signal is regenerated based on the content of the path detection signal obtained by parsing and identifying the path detection signal; the corresponding response signal data may include the path identification and sending time in the corresponding path detection signal, and may also include other data content set according to application requirements. In actual applications, after the inverter station receives the path detection response signal returned by the rectifier station through each communication path, the corresponding response signal data can be obtained by demodulating and decoding each path detection response signal, and then the communication delay of the current detection cycle of the communication path corresponding to the path identification can be obtained based on the difference between the receiving time of the path detection response signal and the sending time of the path detection signal in the response signal data. It should be noted that the inverter station side can be equipped with high-precision time recording hardware on each communication interface, such as a timer chip based on a quartz crystal oscillator (with an accuracy of nanoseconds), to record the time at the moment the signal is received, and through the hardware clock synchronization mechanism, each timer is synchronized with the system clock to ensure the accuracy and comparability of the delay statistics of each communication path.

[0035] According to the minimum value of the path communication delays of all communication paths, the minimum path communication delay within the monitoring period is obtained.

[0036] The embodiment of the present invention configures a multi-path fusion delay detection and path switching mechanism on the inverter station side to periodically monitor the communication delay between stations to switch the communication path between the inverter station and the rectifier station and update the communication delay record between stations, and sends a locking execution instruction to the corresponding rectifier station after the inverter station receives the single valve group locking instruction, configures the inverter side trigger angle limiter integral time and the delayed locking execution time according to the acquired inverter side steady-state trigger angle, AC voltage fluctuation rate, AC frequency deviation and inter-station communication delay, and executes the bracket based on the inverter side trigger angle limiter integral time adaptive adjustment trigger when the delayed locking execution time is reached. The inverter side locking process of the trigger angle moving rate, and when the rectifier station receives the locking execution instruction, the rectifier side trigger angle limiter integration time is configured according to the acquired rectifier side steady-state trigger angle and DC current change rate, and the rectifier side locking process including adaptively adjusting the trigger angle moving rate based on the rectifier side trigger angle limiter integration time is immediately executed. This scheme can not only ensure the consistency of the start and end times of the execution of the ALPHA_90 instruction on the rectifier side and the inverter side, reduce the disturbance caused by the valve withdrawal group to the DC system during operation, effectively improve the operation stability of the AC and DC power grids, but also effectively improve the execution efficiency of the online valve withdrawal group.

[0037] It should be noted that although the steps in the above flowchart are shown in sequence according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders.

[0038] In one embodiment, Figure 4 As shown, a UHV DC online valve group withdrawal system with adaptive trigger angle change is provided, and the system comprises: The inverter station control module 1 is used to respond to the single valve group locking instruction, send a locking execution instruction to the corresponding rectifier station, and configure the inverter side trigger angle limiter integration time and delayed locking execution time according to the acquired inverter side steady-state trigger angle, AC voltage fluctuation rate, AC frequency deviation and inter-station communication delay, and execute the inverter side locking process when the delayed locking execution time is reached; the inverter side locking process includes adaptively adjusting the trigger angle movement rate based on the inverter side trigger angle limiter integration time; The rectifier station control module 2 is used to configure the integration time of the rectifier side trigger angle limiter according to the acquired steady-state trigger angle and DC current change rate of the rectifier side when receiving the locking execution instruction, and immediately execute the rectifier side locking process; the rectifier side locking process includes adaptively adjusting the trigger angle movement rate based on the integration time of the rectifier side trigger angle limiter.

[0039] In one embodiment, the inverter station control module 1 is also used to periodically monitor the path communication delays of different communication paths between the rectifier stations, obtain the minimum path communication delay within the monitoring period, and switch the current inter-station communication path to the communication path corresponding to the minimum path communication delay, and update the inter-station communication delay record according to the minimum path communication delay.

[0040] Specifically, the inverter station periodically monitors the path communication delays of different communication paths with the rectifier station, and the step of obtaining the minimum path communication delay within the monitoring period includes: Periodically generate a path detection signal corresponding to each communication path based on a preset time interval, and simultaneously send the path detection signal to the rectifier station through the corresponding communication path; the path detection signal includes a path identifier and a sending time; Receiving the path detection response signal returned by the rectifier station through each communication path, and obtaining the corresponding path communication delay according to the receiving time of the path detection response signal and the response signal data; the response signal data includes the path identifier and the sending time in the corresponding path detection signal; According to the minimum value of the path communication delays of all communication paths, the minimum path communication delay within the monitoring period is obtained.

[0041] The rectifier station control module 2 is also used to receive the path detection signal sent by the inverter station through different communication paths, generate a corresponding path detection response signal according to the path detection signal, and send the path detection response signal to the inverter station through the corresponding communication path.

[0042] For the specific definition of the UHV DC online valve group withdrawal system with adaptive trigger angle change, please refer to the definition of the UHV DC online valve group withdrawal method with adaptive trigger angle change in the above text, and the corresponding technical effects can also be obtained equivalently, which will not be repeated here. Each module in the above-mentioned UHV DC online valve group withdrawal system with adaptive trigger angle change can be fully or partially implemented by software, hardware and a combination thereof. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above-mentioned modules.

[0043] In summary, an embodiment of the present invention provides an ultra-high voltage direct current online valve group withdrawal method and system with adaptive trigger angle changes. The ultra-high voltage direct current online valve group withdrawal method with adaptive trigger angle changes configures a multi-path fusion delay detection and path switching mechanism on the inverter station side to periodically monitor the communication delay between stations to switch the communication path between the inverter station and the rectifier station and update the communication delay record between stations, and combines the execution time alignment mechanism of the valve group locking instructions on both sides that delays the inverter side to execute the shift trigger angle based on the inter-station communication delay with the adaptive synchronization trigger angle change mechanism that adaptively and reasonably configures the integral time length of the trigger angle limiter on the inverter side and the rectifier side based on the real-time operation conditions of the ultra-high voltage direct current transmission system and the AC system, so that when the valve group locking instruction is actually executed, the shift angle starting time of the rectifier side and the inverter side can be effectively aligned and the consistency of the time length of the shift angle on both sides to 90° can be ensured, so as to realize the adaptive synchronization of the trigger angle changes on both sides, effectively reduce the disturbance caused by the valve group withdrawal during operation to the DC system, improve the operation stability of the AC and DC power grids, and effectively improve the execution efficiency of the online valve group withdrawal.

[0044] Each embodiment in this specification is described in a progressive manner, and the same or similar parts of each embodiment can be directly referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. It should be noted that the technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0045] The above-mentioned embodiments only express several preferred implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principle of the present invention, and these improvements and substitutions should also be regarded as the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for online valve group withdrawal of ultra-high voltage direct current with adaptive trigger angle change, characterized in that: The method comprises the following steps: In response to the single valve group locking instruction, the inverter station sends a locking execution instruction to the corresponding rectifier station, and configures the inverter side trigger angle limiter integration time and the delayed locking execution time according to the acquired inverter side steady-state trigger angle, AC voltage fluctuation rate, AC frequency deviation and inter-station communication delay, and executes the inverter side locking process when the delayed locking execution time is reached; the inverter side locking process includes adaptively adjusting the trigger angle movement rate based on the inverter side trigger angle limiter integration time; When the rectifier station receives the locking execution instruction, it configures the integration time of the trigger angle limiter on the rectifier side according to the acquired steady-state trigger angle and DC current change rate on the rectifier side, and immediately executes the locking process on the rectifier side; the locking process on the rectifier side includes adaptively adjusting the trigger angle movement rate based on the integration time of the trigger angle limiter on the rectifier side.

2. The method for online valve group withdrawal of ultra-high voltage direct current with adaptive trigger angle change according to claim 1, characterized in that: The step of configuring the inverter side trigger angle limiter integration time and delayed locking execution time according to the acquired inverter side steady-state trigger angle, AC voltage fluctuation rate, AC frequency deviation and inter-station communication delay comprises: According to the inverter-side steady-state trigger angle, the AC voltage fluctuation rate and the AC frequency deviation, the preset target angle movement time is adjusted to obtain a first integration time, and the first integration time is configured as an integration time constant in the corresponding inverter-side trigger angle limiter; The delayed locking execution time is obtained according to the sum of the inter-station communication delay and the receiving time corresponding to the single valve group locking instruction.

3. The method for online valve group withdrawal of UHV DC with adaptive trigger angle change according to claim 2, characterized in that: The first integration duration is expressed as: In the formula, Indicates the duration of the first integral; Indicates the duration of the preset target angle movement; and represents a constant coefficient; and They represent the AC voltage fluctuation rate and AC frequency deviation respectively; Indicates the steady-state trigger angle of the inverter side.

4. The method for online valve group withdrawal of UHV DC with adaptive trigger angle change according to claim 1, characterized in that: The step of configuring the integral time length of the rectifier side trigger angle limiter according to the acquired rectifier side steady-state trigger angle and DC current change rate comprises: According to the rectifier-side steady-state trigger angle and the DC current change rate, the preset target angle movement duration is adjusted to obtain a second integration duration, and the second integration duration is configured at the corresponding rectifier-side trigger angle limiter.

5. The method for online valve group withdrawal of UHV DC with adaptive trigger angle change according to claim 4, characterized in that: The second integration time is expressed as: In the formula, Indicates the duration of the second integral; Indicates the duration of the preset target angle movement; represents a constant coefficient; Indicates the rate of change of DC current; Indicates the steady-state firing angle on the rectifier side.

6. The method for online valve group withdrawal of UHV DC with adaptive trigger angle change according to claim 1, characterized in that: The method further comprises: The inverter station periodically monitors the path communication delays of different communication paths with the rectifier station, obtains the minimum path communication delay within the monitoring period, switches the current inter-station communication path to the communication path corresponding to the minimum path communication delay, and updates the inter-station communication delay record according to the minimum path communication delay.

7. The method for online valve group withdrawal of UHV DC with adaptive trigger angle change according to claim 6, characterized in that: The inverter station periodically monitors the path communication delays of different communication paths between the inverter station and the rectifier station, and the step of obtaining the minimum path communication delay within the monitoring period includes: Periodically generate a path detection signal corresponding to each communication path based on a preset time interval, and simultaneously send the path detection signal to the rectifier station through the corresponding communication path; the path detection signal includes a path identifier and a sending time; Receiving the path detection response signal returned by the rectifier station through each communication path, and obtaining the corresponding path communication delay according to the receiving time of the path detection response signal and the response signal data; the response signal data includes the path identifier and the sending time in the corresponding path detection signal; According to the minimum value of the path communication delays of all communication paths, the minimum path communication delay within the monitoring period is obtained.

8. An ultra-high voltage direct current online valve group withdrawal system with adaptive trigger angle change, characterized in that: The system comprises: The inverter station control module is used to respond to the single valve group locking instruction, send a locking execution instruction to the corresponding rectifier station, and configure the inverter side trigger angle limiter integration time and delayed locking execution time according to the acquired inverter side steady-state trigger angle, AC voltage fluctuation rate, AC frequency deviation and inter-station communication delay, and execute the inverter side locking process when the delayed locking execution time is reached; the inverter side locking process includes adaptively adjusting the trigger angle movement rate based on the inverter side trigger angle limiter integration time; The rectifier station control module is used to configure the integration time of the rectifier side trigger angle limiter according to the acquired steady-state trigger angle and DC current change rate of the rectifier side when receiving the lockout execution instruction, and immediately execute the rectifier side lockout process; the rectifier side lockout process includes adaptively adjusting the trigger angle movement rate based on the integration time of the rectifier side trigger angle limiter.

9. The UHV DC online valve withdrawal system with adaptive trigger angle change according to claim 8, characterized in that: The inverter station control module is further used to periodically monitor the path communication delays of different communication paths between the rectifier stations, obtain the minimum path communication delay within the monitoring period, switch the current inter-station communication path to the communication path corresponding to the minimum path communication delay, and update the inter-station communication delay record according to the minimum path communication delay; The rectifier station control module is also used to receive the path detection signal sent by the inverter station through different communication paths, generate a corresponding path detection response signal according to the path detection signal, and send the path detection response signal to the inverter station through the corresponding communication path.

10. The UHV DC online valve withdrawal system with adaptive trigger angle change according to claim 9, characterized in that: The periodic monitoring of the path communication delays of different communication paths between the rectifier stations to obtain the minimum path communication delay within the monitoring period includes: Periodically generate a path detection signal corresponding to each communication path based on a preset time interval, and simultaneously send the path detection signal to the rectifier station through the corresponding communication path; the path detection signal includes a path identifier and a sending time; Receiving the path detection response signal returned by the rectifier station through each communication path, and obtaining the corresponding path communication delay according to the receiving time of the path detection response signal and the response signal data; the response signal data includes the path identifier and the sending time in the corresponding path detection signal; According to the minimum value of the path communication delays of all communication paths, the minimum path communication delay within the monitoring period is obtained.

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