Low-frequency and low-voltage load reduction method and system based on source load attribute execution strategy

Abstract

The invention discloses a low-frequency and low-voltage load reduction method and system based on a source load attribute execution strategy, the method is applied to a low-frequency and low-voltage load reduction device provided with a line cut-allowed soft pressing plate corresponding to a controlled line, and the method comprises the following steps: collecting active power of the controlled line and recording corresponding positive and negative values; setting the switching permission soft pressing plate switching state of the controlled circuit according to the setting value list, and judging whether the setting is successful or not through double-confirmation logic; if the line cut-allowed soft pressing plate of the controlled line is input and the active power is greater than a set threshold value, setting the controlled line to be in a cut-allowed state and bringing the controlled line into a cuttable load capacity to set a tripping outlet matrix; and if the low-frequency or low-voltage fault of the system is identified, executing a load reduction strategy according to the set tripping outlet matrix. When a load reduction strategy is executed, an active line is automatically removed, meanwhile, a line cutting permission soft pressing plate is added, the remote switching and double-confirmation functions are supported, and the dynamic strategy adjustment requirement of a third defense line online monitoring system is met.

Description

Technical Field

[0001] This invention relates to power system protection technology, specifically to a low-frequency, low-voltage load reduction method and system based on source-load attribute execution strategy. Background Technology

[0002] In recent years, frequent large-scale power outages abroad have exposed the need for further optimization and improvement of the three lines of defense in the power system to prevent the escalation of accidents. With the construction and development of new power systems in China, the scale of distributed power source access on the load side is growing rapidly, and load volatility is increasing. The third line of defense of the power system, which is mainly composed of low-frequency and low-voltage load shedding devices, is facing severe challenges. For example, it is difficult to identify active lines, which may lead to the risk of erroneous power line disconnection, and there is a lack of system control conditions to make it difficult to adaptively adjust the device strategy. Therefore, it is urgent to propose a functional optimization and improvement scheme for low-frequency and low-voltage load shedding devices to adapt to the construction of the third line of defense under the new power system and improve the safety and stability control level of the power system. Summary of the Invention

[0003] The technical problem to be solved by this invention is to provide a low-frequency, low-voltage load reduction method and system based on source-load attribute execution strategy, which automatically removes active lines when executing the load reduction strategy, and adds a line cut-off soft pressure plate to support remote commissioning and decommissioning and "double confirmation" functions, so as to meet the dynamic strategy adjustment needs of the third line of defense online monitoring system.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A low-frequency, low-voltage load shedding method based on source-load attribute execution strategy is proposed. The method is applied to a low-frequency, low-voltage load shedding device, which is equipped with a line-cutting soft pressure plate corresponding to the controlled line. The method includes the following steps: Collect the active power of the controlled line and record the corresponding positive and negative values. If the positive and negative values ​​of the active power of the controlled line are inconsistent with the source and load attributes of the controlled line, the positive and negative values ​​of the active power of the controlled line are inverted. Obtain the setting sheet and set the enabling / disabling status of the line cut-off soft pressure plate of the controlled line according to the setting sheet, and determine whether the enabling / disabling status of the line cut-off soft pressure plate of the controlled line is set successfully through double confirmation logic; Obtain the status of the line cut-off soft switch and the value of active power of the controlled line. If the line cut-off soft switch of the controlled line is engaged and the active power is greater than the set threshold value, then set the controlled line to the cut-off state and include the controlled line in the cut-off load to adjust the trip output matrix. If a low-frequency or low-voltage fault is detected in the system, a load reduction strategy is executed according to the set trip output matrix.

[0005] Furthermore, when collecting the active power of the controlled line and recording the corresponding positive and negative values, the following is specifically included: if the controlled line is a load branch, the active power sent by the controlled line is recorded as a positive value; if the controlled line is a power supply branch, the active power sent by the controlled line is recorded as a negative value.

[0006] Furthermore, when setting the on / off status of the line cut-off soft switch of the controlled line according to the setting sheet, it includes: if the controlled line in the setting sheet is a new energy dedicated line connected to the grid, the line cut-off soft switch of the controlled line is set to the off state; if the controlled line in the setting sheet is a pure load feeder, the line cut-off soft switch of the controlled line is set to the on state.

[0007] Furthermore, when determining whether the line cut-off soft switch status of the controlled line is successfully set through double confirmation logic, specifically, the effective status remote signal of the controlled line's output is obtained. If both the effective status remote signal of the controlled line's output and the status of the line cut-off soft switch change accordingly, then the line cut-off soft switch status is successfully set. When either or both of the low-frequency load reduction or low-voltage load reduction functions are engaged, and the line cut-off soft switch of the controlled line is engaged, the status of the effective status remote signal of the output is 1; otherwise, it is 0.

[0008] Furthermore, before obtaining the enabled / disabled status of the line tripping soft switch and the active power value of the controlled line, the following steps are also included: The steps include: obtaining the status or control word of the soft switch for determining power flow direction; if the soft switch status or control word indicates that the power flow direction determination function is engaged, obtaining the enabled / disabled status of the line cut-off soft switch and the value of active power for the controlled line; if the soft switch status or control word indicates that the power flow direction determination function is disengaged, obtaining the enabled / disabled status of the line cut-off soft switch for the controlled line; and if the line cut-off soft switch for the controlled line is engaged, setting the controlled line to the cut-off state and including the controlled line in the cut-off load to adjust the trip output matrix.

[0009] Furthermore, when incorporating the controlled line into the switchable load to set the trip output matrix, the step of incorporating the controlled line into the low-frequency switchable load includes: If the low-frequency load reduction function is activated, and any bus is not under PT maintenance, PT disconnected, or frequency exceeding the limit, and the controlled line in the trip matrix of cycle a is set to 1, then the controlled line is included in the load shedding calculation of cycle a, and the sum of the current active power of each line branch set to 1 and in the allowable tripping state in the trip matrix of cycle a is calculated as the low-frequency load shedding of cycle a.

[0010] Furthermore, when incorporating the controlled line into the switchable load to set the trip output matrix, the step of incorporating the controlled line into the low-voltage switchable load includes: If the low-voltage load reduction function is activated, and any busbar is not under PT maintenance, PT disconnection, or frequency over-limit abnormality, and the controlled line in the trip matrix of cycle a is set to 1, then the controlled line is included in the load shedding calculation of cycle a, and the sum of the current active power of each line branch set to 1 and in the allowable shedding state in the trip matrix of cycle a is calculated as the low-voltage load shedding of cycle a.

[0011] Furthermore, when a low-frequency or low-voltage fault occurs in the system, specifically when the operating bus with no PT disconnection or frequency exceeding the limit meets the low-frequency or low-voltage fault operation conditions.

[0012] This invention also proposes a low-frequency, low-voltage load shedding system, including a line protection and control device, a load acquisition unit, and a low-frequency, low-voltage load shedding device. The load acquisition unit receives and extracts active power information of the entire station's controlled lines from the line protection and control device, and sends the extracted active power information to the low-frequency, low-voltage load shedding device. The low-frequency, low-voltage load shedding device is programmed or configured to execute the low-frequency, low-voltage load shedding method based on the source-load attribute execution strategy described in any one of the inventions.

[0013] Furthermore, the load acquisition unit communicates with the line protection and control device using the 61850 or 104 protocol to receive and extract the active power information of the controlled lines throughout the station. The load acquisition unit communicates with the low-frequency low-voltage load reduction device using the UDP or 104 protocol and sends the extracted line active power information to the low-frequency low-voltage load reduction device.

[0014] Compared with the prior art, the advantages of the present invention are as follows: This invention collects the active power of the controlled lines and records the corresponding positive and negative values. It then performs consistency checks and inversion processing based on "source-load attributes." Simultaneously, it sets controlled lines with active power exceeding a set threshold and enabled by the activation of the line cutoff soft switch, classifying them as cutoff-allowed and including them in the cutoff load list. This allows the acquisition of line power flow information to identify active lines, automatically removing them during load reduction strategies. Through an active power direction and source-load attribute matching mechanism, it accurately filters truly cutoff loads, avoiding accidental power supply or critical user disconnection.

[0015] This invention incorporates eligible lines into the tripping capacity to adjust the tripping output matrix, and specifically sets up line tripping soft pressure plates corresponding to the controlled lines. Through the dynamic correlation mechanism between the soft pressure plates and the load, real-time statistics of tripping capacity and flexible adjustment of the output matrix are achieved, improving the accuracy and adaptability of strategy execution.

[0016] This invention acquires a setting sheet and sets the enabling / disabling status of the line-allowed soft switch plate for the controlled line according to the setting sheet. It then uses a double-confirmation logic to determine whether the enabling / disabling status of the line-allowed soft switch plate for the controlled line has been successfully set. It supports remote enabling / disabling and a "double-confirmation" function. Through a dual-confirmation mechanism of remote setting issuance and status feedback, it ensures the safety and reliability of remote operations, meeting the safety protection requirements of power monitoring systems.

[0017] This invention dynamically sets the soft pressure plate status by acquiring setting sheets, adjusts the trip output matrix based on real-time power flow, and executes load reduction strategies according to the adjusted trip output matrix after fault identification. Through dynamic adjustment of the entire process—remote setting updates, online adjustment of the output matrix, and real-time strategy execution—it meets the operational requirements of the power grid's third line of defense for rapid response and flexible adaptation to load reduction strategies. Attached Figure Description

[0018] Figure 1 This is a flowchart of a method according to an embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram showing the relationship between the active power of the line and the allowable shunt state. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention.

[0021] Existing low-frequency, low-voltage load shedding devices cannot identify active lines and adaptively adjust their strategies. They cannot distinguish between load lines, power lines, or out-of-service lines in real time, and there is a risk of mistakenly disconnecting power lines when the devices operate, further deteriorating the system frequency. In addition, existing low-frequency, low-voltage load shedding devices lack systematic remote control capabilities. When the regional low-frequency load shedding capacity is insufficient or excessive, real-time adjustment of the strategy cannot be achieved, and the effectiveness of the strategy cannot be guaranteed.

[0022] To address the aforementioned problems of existing low-frequency and low-voltage load shedding devices, this embodiment proposes a low-frequency and low-voltage load shedding method based on source-load attribute execution strategy. This method is applied to a low-frequency and low-voltage load shedding device equipped with line cut-off soft pressure plates corresponding to the controlled lines. The core idea is to identify active lines based on the line power flow information obtained from the station control layer network, automatically remove active lines when executing the load shedding strategy, and simultaneously calculate the load shedding capacity in real time and increase the line cut-off soft pressure plates. It supports remote commissioning and decommissioning and "double confirmation" functions, adapting to the dynamic strategy adjustment requirements of the third-line online monitoring system.

[0023] like Figure 1 As shown, the method includes the following steps: S1) Collect the active power of the controlled line X and record the corresponding positive and negative values. If the positive and negative values ​​of the active power of the controlled line X are inconsistent with the source-load attributes of the controlled line X, the positive and negative values ​​of the active power of the controlled line X shall be inverted. S2) Obtain the setting sheet and set the line cut-off soft switch of the controlled line X to the on / off state according to the setting sheet, and determine whether the line cut-off soft switch of the controlled line X is successfully set through double confirmation logic; obtain the line cut-off soft switch of the controlled line X and the active power value. If the line cut-off soft switch of the controlled line X is on and the active power is greater than the set threshold value, then set the controlled line X to the cut-off state. S3) If the controlled line X is in the tripping state, the controlled line X is included in the tripping load to set the tripping output matrix; S4) If a low-frequency or low-voltage fault is detected in the system, the load reduction strategy is executed according to the set trip output matrix.

[0024] Through the above steps, this embodiment can realize source and load attribute identification on the device side. In the event of a power grid accident, even if the device is interrupted in communication with the upstream, the device itself can complete the output strategy adjustment in real time, reducing the risk of further deterioration of system frequency and voltage due to accidental disconnection of power supply branches.

[0025] Through step S1 of this embodiment, the low-frequency low-voltage load reduction device is designed with line active power acquisition function. It can obtain the active power of the controlled line in the station by adding a load acquisition unit to interact with the line protection and control device based on the station control layer network.

[0026] The load acquisition unit and the line protection and control device can communicate using protocols such as 61850 or 104 to receive and extract information such as the active power of the controlled lines throughout the station.

[0027] Furthermore, the load acquisition unit and the low-frequency low-voltage load shedding device can communicate using protocols such as UDP or 104, and the extracted line active power and other information can be sent to the low-frequency low-voltage load shedding device in a "periodic + variable" manner.

[0028] Furthermore, through step S1 of this embodiment, the low-frequency low-voltage load shearing device is designed with a function to invert the active power of the line. The active power unit is specified as MW. When the active power is in the outward direction (the line is a load), it is a positive value; when the active power is in the inward direction (the line is a power source), it is a negative value. Therefore, when collecting the active power of the controlled line X and recording the corresponding positive and negative values, it specifically includes: if the controlled line X is a load branch, the active power sent by the controlled line X is recorded as a positive value; if the controlled line X is a power source branch, the active power sent by the controlled line X is recorded as a negative value.

[0029] Considering that the power sign may differ from the specified sign due to reverse connection of the PT or CT, the sign can be reversed at the device side to resolve the issue of the load or power supply active power sign differing from the theoretical value due to differences in PT or CT connection installation. During the installation and commissioning phase, when the received active power sign is inconsistent with the specified source-load attributes of the corresponding line, the active power of that line can be reversed by modifying parameters during further logic processing.

[0030] Through step S2 of this embodiment, the low-frequency low-voltage load shearing device is designed with a line active power direction determination function for enabling / disabling. This function can be enabled / disabling via a soft switch or control word. When this function is disabled, the line with the line cut-off soft switch engaged is in the cut-off state; when this function is enabled, the line is in the cut-off state only when the line cut-off soft switch is engaged and the active power is greater than a certain set threshold value Px.

[0031] In this embodiment, whether the line branch's allowable cut-off soft switch is engaged can be determined according to the setting sheet issued by the dispatcher. When setting the engagement / disengagement status of the line allowable cut-off soft switch of the controlled line X according to the setting sheet, it includes: if the controlled line X in the setting sheet is a new energy dedicated line connected to the grid, the line allowable cut-off soft switch of the controlled line X is set to the disengagement status; if the controlled line X in the setting sheet is a pure load feeder, the line allowable cut-off soft switch of the controlled line X is set to the engagement status.

[0032] In this embodiment, the line cut-off soft pressure plate is installed at line intervals in the low-frequency low-voltage load shedding device, supporting remote activation / deactivation and "double confirmation" functions. Therefore, a remote signaling function for the effective status of line X outlet is designed. The criterion is that when either the low-frequency load shedding or low-voltage load shedding function is activated, or both are activated, and the line X cut-off soft pressure plate is activated, the remote signaling status is 1; otherwise, it is 0. Furthermore, the "double confirmation" logic for the line cut-off soft pressure plate uses changes in both the line X line cut-off soft pressure plate's own status and the effective status of the line X outlet as the criterion for successful operation. Therefore, when determining whether the line cut-off soft switch status of the controlled line is successfully set through double confirmation logic, the specific method is to obtain the output effective status remote signal of the controlled line. If both the output effective status remote signal of the controlled line and the status of the line cut-off soft switch of the controlled line change accordingly, then the line cut-off soft switch status is successfully set. When either or both of the low-frequency load reduction or low-voltage load reduction functions are engaged, and the line cut-off soft switch of the controlled line is engaged, the status of the output effective status remote signal is 1; otherwise, it is 0.

[0033] In addition, before obtaining the on / off status of the line trip soft switch and the active power value of the controlled line, the following steps are also included: The steps include: obtaining the status or control word of the soft switch for determining power flow direction; if the soft switch status or control word indicates that the power flow direction determination function is engaged, obtaining the enabled / disabled status of the line cut-off soft switch and the value of active power for the controlled line; if the soft switch status or control word indicates that the power flow direction determination function is disengaged, obtaining the enabled / disabled status of the line cut-off soft switch for the controlled line; and if the line cut-off soft switch for the controlled line is engaged, setting the controlled line to the cut-off state and including the controlled line in the cut-off load to adjust the trip output matrix.

[0034] In step S2 of this embodiment, setting a threshold value Px as an active power dead zone setting is to prevent frequent abrupt changes in the load shedding state due to sampling errors or power flow direction fluctuations. Simultaneously, to ensure that the low-frequency low-voltage load shedding device can effectively shed the load and prevent the automatic standby power supply device from restoring power to the shedding load, the main and backup power lines must be disconnected together during load shedding. Lines in hot standby state have zero active power and should be disconnected. Therefore, lines with active power in the dead zone are allowed to be disconnected and should be disconnected when activated. A schematic diagram of the relationship between line active power and allowed-to-disconnect state is shown below. Figure 2 As shown.

[0035] Through step S3 of this embodiment, the low-frequency and low-voltage load shedding device calculates and uploads information such as the total amount of low-frequency load that can be shelved, the total amount of low-voltage load that can be shelved, the amount of low-frequency load that can be shelved in each round, and the amount of low-voltage load that can be shelved in each round, based on information such as the activation of low-frequency and low-voltage functions, the line shelving status, and the tripping matrix of each round.

[0036] The calculation logic for the shearable load in each low-frequency cycle is as follows: When the low-frequency low-voltage load shearing device is not locked, the low-frequency load shearing function is activated in that cycle, and any busbar is not under PT maintenance, PT disconnection, or frequency over-limit anomaly, the shearable load is the sum of the current active power of all line branches in that cycle with the output matrix set to 1 and in a shearing state. Conversely, if the low-frequency low-voltage load shearing device is locked, or the low-frequency load shearing function is deactivated in that cycle, or all buses are under PT maintenance, PT disconnection, or frequency over-limit anomaly, then the shearable load for that cycle is 0. Furthermore, the calculation logic for the total shearable load in low-frequency cycles is: the sum of the shearable loads in each low-frequency cycle.

[0037] Similarly, the calculation logic for the shearable load of each low-voltage cycle is as follows: When the low-frequency low-voltage load shearing device is not locked, the low-voltage load shearing function is activated and the cycle is not in operation, and any busbar is not under PT maintenance, PT disconnection, or frequency over-limit anomaly, the shearable load is the sum of the current active power of all line branches in the cycle with the output matrix set to 1 and in the allowable shearing state. Conversely, if the low-frequency low-voltage load shearing device is locked, or the low-voltage load shearing function is deactivated and the cycle is not in operation, or all busesbars are under PT maintenance, PT disconnection, or frequency over-limit anomaly, then the shearable load of that cycle is 0. Furthermore, the calculation logic for the total shearable load of low-voltage is: the sum of the shearable loads of each low-voltage cycle.

[0038] Therefore, when incorporating the controlled line into the switchable load to set the trip output matrix, the step of incorporating the controlled line into the low-frequency switchable load includes: If the low-frequency load reduction function is activated, and any bus is not under PT maintenance, PT disconnected, or frequency exceeding the limit, and the controlled line in the trip matrix of cycle a is set to 1, then the controlled line is included in the load shedding calculation of cycle a, and the sum of the current active power of each line branch set to 1 and in the allowable tripping state in the trip matrix of cycle a is calculated as the low-frequency load shedding of cycle a.

[0039] Furthermore, when incorporating the controlled line into the switchable load to set the trip output matrix, the step of incorporating the controlled line into the low-voltage switchable load includes: If the low-voltage load reduction function is activated, and any busbar is not under PT maintenance, PT disconnection, or frequency over-limit abnormality, and the controlled line in the trip matrix of cycle a is set to 1, then the controlled line is included in the load shedding calculation of cycle a, and the sum of the current active power of each line branch set to 1 and in the allowable shedding state in the trip matrix of cycle a is calculated as the low-voltage load shedding of cycle a.

[0040] In step S4 of this embodiment, to improve the reliability of the low-frequency and low-voltage load shedding device, when a low-frequency or low-voltage fault is detected in the system, specifically when the operating bus with no PT disconnection or frequency exceeding the limit meets the low-frequency or low-voltage fault operation conditions, the low-frequency and low-voltage load shedding device automatically removes the lines that are not allowed to be disconnected and then executes the load shedding strategy according to the set trip output matrix.

[0041] The following is a specific example to illustrate the effect of the method in this embodiment: A low-frequency, low-voltage load shedding device has functions such as low-frequency load shedding and low-voltage load shedding. Each function has multiple cycles and can support the shedding of X line bays. In order to achieve different numbers of line bays being tripped in different cycles, the number of trips in each cycle is controlled by the trip output matrix. If X is 16, then the trip output matrix of each cycle is a 16-bit binary number, which corresponds to the outputs of line bays 1 to 16 from low to high bits. Its setting range is 0000 to FFFF in hexadecimal.

[0042] When the first round of low-frequency load shedding requires tripping lines 1-8, the tripping output matrix setting for this round is set to 00FF. If steps S1 to S3 are executed, the active power of lines 1-7 is P1-P7 respectively, which is greater than the set threshold value Px; the active power of line 8 is P8, which is less than the set threshold value Px. Therefore, lines 1-7 are allowed to be tripped, and line 8 is not allowed to be tripped. Under normal conditions and with the function activated for this round, the load shedding capacity for this round is P1+P2+......+P7. Conversely, if there is an abnormality or the function is not activated for this round, the load shedding capacity for this round is 0.

[0043] In step S4, when executing the load reduction strategy for this round, only lines 1 to 7 are tripped, thereby automatically eliminating lines that are not allowed to be tripped. However, for traditional low-frequency low-voltage load reduction devices, when the first round of low-frequency load reduction requires tripping lines 1 to 8, the tripping output matrix setting for this round is set to 00FF. When executing the load reduction strategy for this round, lines 1 to 8 are directly tripped, and active lines cannot be automatically eliminated when executing the load reduction strategy.

[0044] Furthermore, this embodiment also proposes a low-frequency, low-voltage load shedding system, including a line protection and control device, a load acquisition unit, and a low-frequency, low-voltage load shedding device. The low-frequency, low-voltage load shedding device is programmed or configured to execute the low-frequency, low-voltage load shedding method based on source-load attribute execution strategy described in this embodiment. The load acquisition unit receives and extracts the active power information of all controlled lines in the station from the line protection and control device, and sends the extracted active power information to the low-frequency, low-voltage load shedding device. Specifically, the load acquisition unit communicates with the line protection and control device using the 61850 or 104 protocol to receive and extract the active power information of all controlled lines in the station, and the load acquisition unit communicates with the low-frequency, low-voltage load shedding device using the UDP or 104 protocol, and sends the extracted active power information to the low-frequency, low-voltage load shedding device.

[0045] In summary, this invention proposes a low-frequency, low-voltage load reduction method based on source-load attribute execution strategy, applies it to low-frequency, low-voltage load reduction devices, and also proposes a corresponding low-frequency, low-voltage load reduction system. By collecting line information, it addresses the problems of erroneous and over-cutting caused by the inability to perceive the source-load status at the line end, achieving adaptive identification of active lines and adaptive adjustment of the load reduction scheme. Simultaneously, it calculates the cuttable load in real time and designs a line cut-off soft pressure plate, supporting remote deployment and deactivation and "double confirmation" functions. This provides strong support for achieving overall observability, measurability, and controllability of the third line of defense system. Compared with existing technologies, it has the following advantages: (1) It has the ability to identify the source and load attributes of the line. When a low-frequency or low-voltage fault is detected in the system, it automatically removes the branch that cannot be cut off, effectively preventing the problem of further deterioration of the power grid system caused by the cutting off of the power supply branch.

[0046] (2) Based on the station control layer network, the power flow information of the line is obtained to identify the active line. No additional cables are needed for the renovation and expansion project, which is convenient for renovation and upgrading.

[0047] (3) It can transmit the total amount of low-frequency load that can be cut off, the total amount of low-voltage load that can be cut off, the amount of low-frequency load that can be cut off in each cycle, and the amount of low-voltage load that can be cut off in each cycle, providing strong support for the third line of defense to be observable and measurable.

[0048] (4) Each line is designed with an independent line cut-off soft pressure plate, which supports remote deployment and withdrawal and "double confirmation" functions, providing a basis for real-time adjustment and controllability of the third line of defense strategy.

[0049] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-readable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create a machine for implementing the process. Figure 1 One or more processes and / or boxes Figure 1The computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The functions specified in one or more boxes. These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable apparatus for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0050] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A low-frequency, low-voltage load shedding method based on source load attribute execution strategy, characterized in that, The method is applied to a low-frequency, low-voltage load shearing device, which is equipped with a line cut-off soft pressure plate corresponding to the controlled line. The method includes the following steps: Collect the active power of the controlled line and record the corresponding positive and negative values. If the positive and negative values ​​of the active power of the controlled line are inconsistent with the source and load attributes of the controlled line, the positive and negative values ​​of the active power of the controlled line are inverted. Obtain the setting sheet and set the enabling / disabling status of the line cut-off soft pressure plate of the controlled line according to the setting sheet, and determine whether the enabling / disabling status of the line cut-off soft pressure plate of the controlled line is set successfully through double confirmation logic; Obtain the status of the line cut-off soft switch and the value of active power of the controlled line. If the line cut-off soft switch of the controlled line is engaged and the active power is greater than the set threshold value, then set the controlled line to the cut-off state and include the controlled line in the cut-off load to adjust the trip output matrix. If a low-frequency or low-voltage fault is detected in the system, a load reduction strategy is executed according to the set trip output matrix.

2. The low-frequency, low-voltage load shedding method based on source-load attribute execution strategy according to claim 1, characterized in that, When collecting the active power of the controlled line and recording the corresponding positive and negative values, the following is specifically included: if the controlled line is a load branch, the active power sent by the controlled line is recorded as a positive value; if the controlled line is a power supply branch, the active power sent by the controlled line is recorded as a negative value.

3. The low-frequency, low-voltage load shedding method based on source-load attribute execution strategy according to claim 1, characterized in that, When setting the line cut-off soft switch status of the controlled line according to the setting sheet, the following applies: if the controlled line in the setting sheet is a new energy dedicated line connected to the grid, the line cut-off soft switch of the controlled line is set to the off state; if the controlled line in the setting sheet is a pure load feeder, the line cut-off soft switch of the controlled line is set to the on state.

4. The low-frequency, low-voltage load shedding method based on source-load attribute execution strategy according to claim 1, characterized in that, When determining whether the line cut-off soft switch status of the controlled line is successfully set by double confirmation logic, specifically by obtaining the output effective status remote signal of the controlled line, if both the output effective status remote signal and the line cut-off soft switch status of the controlled line change accordingly, then the line cut-off soft switch status is successfully set. When either or both of the low-frequency load reduction or low-voltage load reduction functions are engaged, and the line cut-off soft switch of the controlled line is engaged, the status of the output effective status remote signal is 1; otherwise, it is 0.

5. The low-frequency, low-voltage load shedding method based on source-load attribute execution strategy according to claim 1, characterized in that, Before obtaining the controllable line's allowable switching status and active power values, the following steps are also included: The steps include: obtaining the status or control word of the soft switch for determining power flow direction; if the soft switch status or control word indicates that the power flow direction determination function is engaged, obtaining the enabled / disabled status of the line cut-off soft switch and the value of active power for the controlled line; if the soft switch status or control word indicates that the power flow direction determination function is disengaged, obtaining the enabled / disabled status of the line cut-off soft switch for the controlled line; and if the line cut-off soft switch for the controlled line is engaged, setting the controlled line to the cut-off state and including the controlled line in the cut-off load to adjust the trip output matrix.

6. The low-frequency, low-voltage load shedding method based on source-load attribute execution strategy according to claim 1, characterized in that, When incorporating the controlled line into the switchable load to set the trip output matrix, the step of incorporating the controlled line into the low-frequency switchable load includes: If the low-frequency load reduction function is activated, and any bus is not under PT maintenance, PT disconnected, or frequency exceeding the limit, and the controlled line in the trip matrix of cycle a is set to 1, then the controlled line is included in the load shedding calculation of cycle a, and the sum of the current active power of each line branch set to 1 and in the allowable tripping state in the trip matrix of cycle a is calculated as the low-frequency load shedding of cycle a.

7. The low-frequency, low-voltage load shedding method based on source-load attribute execution strategy according to claim 1, characterized in that, When incorporating the controlled line into the shelvable load to set the trip output matrix, the process includes the step of incorporating the controlled line into the low-voltage shelvable load, including: If the low-voltage load reduction function is activated, and any busbar is not under PT maintenance, PT disconnection, or frequency over-limit abnormality, and the controlled line in the trip matrix of cycle a is set to 1, then the controlled line is included in the load shedding calculation of cycle a, and the sum of the current active power of each line branch set to 1 and in the allowable shedding state in the trip matrix of cycle a is calculated as the low-voltage load shedding of cycle a.

8. The low-frequency, low-voltage load shedding method based on source-load attribute execution strategy according to claim 1, characterized in that, When a low-frequency or low-voltage fault is identified in the system, specifically, the operating bus with no PT disconnection or frequency exceeding the limit meets the low-frequency or low-voltage fault operation conditions.

9. A low-frequency, low-voltage load shearing system, characterized in that, The system includes a line protection and control device, a load acquisition unit, and a low-frequency, low-voltage load reduction device. The load acquisition unit receives and extracts the active power information of the entire station's controlled lines from the line protection and control device, and sends the extracted active power information to the low-frequency, low-voltage load reduction device. The low-frequency, low-voltage load reduction device is programmed or configured to execute the low-frequency, low-voltage load reduction method based on source-load attribute execution strategy as described in any one of claims 1 to 8.

10. The low-frequency, low-voltage load shearing system according to claim 9, characterized in that, The load acquisition unit communicates with the line protection and control device using the 61850 or 104 protocol to receive and extract the active power information of the controlled lines throughout the station. The load acquisition unit communicates with the low-frequency low-voltage load reduction device using the UDP or 104 protocol and sends the extracted line active power information to the low-frequency low-voltage load reduction device.

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