A distributed power station domain collaborative control protection method and system

Abstract

The application provides a distributed power station field cooperative control protection method and system, the method comprises the following steps: collecting state quantity data of a power system; positioning the position of a low-voltage side pressureless bus according to the state quantity data; judging whether to send an action instruction according to an action logic; the action logic comprises line fault and action logic meeting a normal splitting function criterion, line fault and action logic not meeting the normal splitting function criterion, main transformer high-voltage side fault action logic and main transformer low-voltage side fault action logic; when the action instruction is sent, splitting is set, and small power lines on the low-voltage side pressureless bus are cut off. The application can realize automatic judgment of bus feeder functions needing splitting under different operation modes, automatic detection of small power line output states, and automatic recovery and grid connection after small power line splitting.

Description

Technical Field

[0001] This invention belongs to the field of power system relay protection technology, and particularly relates to a distributed power station regional collaborative control and protection method and system. Background Technology

[0002] Distributed energy resources have advantages such as low investment costs and flexible power generation methods, and their power generation and grid connection rates are gradually increasing. The new power system is showing a trend of "high proportion of renewable energy," leading to profound changes in the system's transient characteristics and posing new challenges to relay protection research.

[0003] After photovoltaic (PV) power is connected to the grid, the grid structure changes from a single-source radial network to a complex topology with dual or multiple power sources. Furthermore, its voltage and frequency support characteristics differ significantly from those of conventional units such as hydropower and thermal power. When the main power supply to the grid fails, PV power generation provides support for the bus voltage. The residual voltage on the bus directly affects the line protection devices' ability to determine if the reclosing re-closing condition is not met, the automatic transfer switch's voltage loss condition is not met, and the sensitivity of the fault tripping device is reduced. Incorrect protection actions will lead to the fault not being eliminated in a timely manner, expanding the power outage area, and greatly impacting power supply reliability.

[0004] The main problems with existing fault disconnection devices are: First, they require frequent operation under different operating modes and cannot automatically identify the operating mode; second, they are prone to accidental load disconnection and it is difficult to accurately disconnect small power lines; third, the grid connection time of disconnected small power lines is long, which is not conducive to the automatic recovery of small power lines. Summary of the Invention

[0005] The purpose of this invention is to propose a distributed power station domain collaborative control and protection method and system to realize the functions of automatically determining the bus feeder lines that need to be disconnected under different operating modes, automatically detecting the output status of small power lines, and automatically restoring grid connection after the small power lines are disconnected.

[0006] To achieve the above objectives, in a first aspect, embodiments of the present invention provide a distributed power station domain collaborative control and protection method, the method comprising: The state data collected from the power system includes at least input quantities, analog quantities, output quantities, and MMS network data. The location of the low-voltage side undervoltage busbar is determined based on the aforementioned status data. Based on the action logic, it is determined whether to send an action command; the action logic includes action logic for line faults that meet the criteria for conventional disconnection function, action logic for line faults that do not meet the criteria for conventional disconnection function, action logic for high-voltage side faults of main transformers, and action logic for low-voltage side faults of main transformers. When an action command is sent, the circuit is set to disconnect and the small power supply line on the low-voltage side undervoltage bus is cut off.

[0007] Furthermore, determining whether to send an action command based on the action logic includes: When the action logic is a line fault and meets the action logic of the conventional disconnection function, it is determined whether the phase voltage at the installation point of the current transformer on the low-voltage side undervoltage bus is greater than the first predetermined voltage. If it is greater, an action command is sent; otherwise, no action command is sent. When the action logic is a line fault and does not meet the action logic of the conventional disconnection function, it is determined whether there is line protection. If there is line protection, an action command is sent when both the line protection action signal and the line circuit breaker change signal are received simultaneously. If there is no line protection, when the line fault is a permanent fault, an action command is sent through the power direction discrimination element. When the line fault is a transient fault, it is determined whether the fault current at the installation point of the low-voltage side feeder line protection is less than the rated current and whether the phase voltage at the installation point of the current transformer on the low-voltage side undervoltage bus is greater than the second predetermined voltage. If these conditions are met, an action command is sent; otherwise, no action command is sent. When the action logic is the fault action logic of the high voltage side of the main transformer, it is determined whether the phase voltage at the installation point of the current transformer on the low voltage side undervoltage bus is greater than the third predetermined voltage. If it is greater, an action command is sent; otherwise, no action command is sent. When the action logic is the fault action logic of the low-voltage side of the main transformer, if the main transformer protection action signal and the low-voltage side circuit breaker change signal are received at the same time, an action command is sent.

[0008] Furthermore, the first predetermined voltage, the second predetermined voltage, and the third predetermined voltage are set according to the rated phase voltage of the low-voltage side bus.

[0009] Furthermore, the step of setting up disconnection and disconnecting the small power lines on the low-voltage side undervoltage bus when the action command is sent includes: setting up two rounds of disconnection when the action command is sent, and disconnecting the small power lines on the low-voltage side undervoltage bus in the order of the two rounds of disconnection.

[0010] Furthermore, the step of setting up two rounds of disconnection when sending the action command, and disconnecting the small power lines on the low-voltage side undervoltage bus in the order of the two rounds of disconnection, includes: The first round of disconnection is set according to the automatic detection function of the output status of the small power line or the preset interval; the automatic detection function of the output status of the small power line includes using the transformer low-voltage side feeder protection device to collect the power and direction of the small power line, and to determine the power supply status and magnitude of the small power line to the grid. A second round of disconnection is performed on all small power supply lines on the low-voltage side undervoltage bus.

[0011] Furthermore, locating the position of the low-voltage side undervoltage bus based on the state data further includes: Based on the circuit breaker's open / closed status, locate the section on the low-voltage side undervoltage busbar where the low-voltage side undervoltage fault occurred.

[0012] Furthermore, if the phase voltage at the transformer installation point on the low-voltage side undervoltage busbar returns to normal within a preset time and the disconnected small power supply line is detected to be without voltage, then the disconnected small power supply line is closed sequentially according to the circuit breaker's open / closed state.

[0013] Secondly, embodiments of the present invention provide a distributed power station domain collaborative control and protection system. The system includes: a data acquisition module, a busbar positioning module, a logic judgment module, and a protection action module. The data acquisition module is connected to the busbar positioning module, the logic judgment module, and the protection action module, respectively. The busbar positioning module is connected to the logic judgment module, and the logic judgment module is connected to the protection action module. The data acquisition module is used to acquire state data of the power system, which includes at least input quantities, analog quantities, output quantities and MMS network data. The busbar positioning module is used to locate the position of the low-voltage side undervoltage busbar based on the status data. The logic judgment module is used to determine whether to send an action command based on the action logic; the action logic includes action logic for line faults that meet the criteria for conventional disconnection function, action logic for line faults that do not meet the criteria for conventional disconnection function, action logic for high-voltage side faults of the main transformer, and action logic for low-voltage side faults of the main transformer. The protection action module is used to set up disconnection and disconnect the small power supply line on the low-voltage side undervoltage bus when an action command is sent.

[0014] Furthermore, the logic judgment module is also used for: When the action logic is a line fault and meets the action logic of the conventional disconnection function, it is determined whether the phase voltage at the installation point of the current transformer on the low-voltage side undervoltage bus is greater than the first predetermined voltage. If it is greater, an action command is sent; otherwise, no action command is sent. When the action logic is a line fault and does not meet the action logic of the conventional disconnection function, it is determined whether there is line protection. If there is line protection, an action command is sent when both the line protection action signal and the line circuit breaker change signal are received simultaneously. If there is no line protection, when the line fault is a permanent fault, an action command is sent through the power direction discrimination element. When the line fault is a transient fault, it is determined whether the fault current at the installation point of the low-voltage side feeder line protection is less than the rated current and whether the phase voltage at the installation point of the current transformer on the low-voltage side undervoltage bus is greater than the second predetermined voltage. If these conditions are met, an action command is sent; otherwise, no action command is sent. When the action logic is the fault action logic of the high voltage side of the main transformer, it is determined whether the phase voltage at the installation point of the current transformer on the low voltage side undervoltage bus is greater than the third predetermined voltage. If it is greater, an action command is sent; otherwise, no action command is sent. When the action logic is the fault action logic of the low-voltage side of the main transformer, if the main transformer protection action signal and the low-voltage side circuit breaker change signal are received at the same time, an action command is sent.

[0015] Furthermore, the protection action module is also used for: When an action command is sent, two rounds of disconnection are set up, and the small power lines on the low-voltage side undervoltage bus are disconnected in the order of the two rounds of disconnection.

[0016] This invention provides a distributed power station domain collaborative control and protection method and system. It collects power system status data; locates the position of the low-voltage side undervoltage bus based on the status data; and determines whether to send an action command based on action logic. The action logic includes action logic for line faults meeting the conventional disconnection function criteria, action logic for line faults not meeting the conventional disconnection function criteria, action logic for main transformer high-voltage side faults, and action logic for main transformer low-voltage side faults. When an action command is sent, disconnection is initiated, and the small power supply lines on the low-voltage side undervoltage bus are disconnected. This invention can automatically determine the bus feeder lines that need to be disconnected under different operating modes, automatically detect the output status of small power supply lines, and automatically restore grid connection after the small power supply lines are disconnected. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating a distributed power station domain collaborative control and protection method according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the 110kV internal bridge wiring provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of a fault disconnection device for 110kV internal bridge wiring provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of a 110kV internal bridge connection main transformer provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the automatic power output detection function of a small power line provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of the small power line disconnection and self-recovery function provided in an embodiment of the present invention; Figure 7 This is a system block diagram of a distributed power station domain collaborative control and protection system according to an embodiment of the present invention; Detailed Implementation To make the objectives, technical solutions, and beneficial effects of this application clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Obviously, the embodiments described below are only part of the embodiments of the present invention and are used to illustrate the present invention, but are not intended to limit the scope of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0018] In one embodiment, such as Figure 1 As shown, the present invention provides a distributed power station domain collaborative control and protection method, the method comprising: S11. Collect state data of the power system, wherein the state data includes at least input quantities, analog quantities, output quantities and MMS network data; This embodiment is applied to Figure 2 The 110kV internal bridge connection shown includes circuit breaker positions and protection action signals. Circuit breaker positions include incoming line circuit breaker positions, bridge section circuit breaker positions, main transformer high-voltage side circuit breaker positions, main transformer low-voltage side circuit breaker positions, and low-voltage section circuit breaker positions. Conventional stations connect to circuit breaker auxiliary contacts, while intelligent stations acquire circuit breaker positions via GOOSE. Protection action signals include line protection action signals, main transformer protection action signals, bridge section protection action signals, and low-voltage side section protection action signals. Conventional stations obtain these signals from the protection device hard contacts, while intelligent stations connect via GOOSE. Analog quantities include three-phase voltage, zero-sequence voltage, and three-phase current of the high-voltage side bus. Conventional stations are connected via cables, while intelligent stations are connected via SV. The output includes the opening and closing outputs of all small power line circuit breakers, which can be obtained via cable or GOOSE message, and is not limited by the type of substation.

[0019] MMS network data includes low-voltage side feeder circuit breakers, power, tripping and closing, and low-voltage side sectional circuit breakers. The MMS network data is converted into GOOSE messages through a communication device and sent to the data acquisition module. This embodiment collects various power grid system data, such as input quantities, analog quantities, output quantities, and MMS network data, and then locates the low-voltage side undervoltage bus in the subsequent process.

[0020] S12. Locate the position of the low-voltage side undervoltage busbar based on the state data; To further determine the specific location of the low-voltage side undervoltage busbar, this embodiment locates the section of the low-voltage side undervoltage busbar where the low-voltage side undervoltage fault occurred based on the circuit breaker's open / closed status. For example, if the current faulty busbar location is determined to be Bus I, the undervoltage of section 1 of the low-voltage side busbar is determined based on the circuit breaker's open / closed status. This embodiment can more accurately determine the specific location of the low-voltage side undervoltage busbar.

[0021] S13. Determine whether to send an action command based on the action logic; the action logic includes action logic for line faults that meet the criteria for conventional disconnection function, action logic for line faults that do not meet the criteria for conventional disconnection function, action logic for high-voltage side faults of the main transformer, and action logic for low-voltage side faults of the main transformer. Specifically, when the action logic is a line fault and meets the action logic of the conventional disconnection function, it is determined whether the phase voltage at the installation point of the current transformer on the low-voltage side undervoltage bus is greater than the first predetermined voltage. If it is greater, an action command is sent; otherwise, no action command is sent. In this embodiment, the conventional tripping function's action logic includes satisfying one of the following: low-frequency action criterion, low-voltage action criterion, over-frequency action criterion, over-voltage action criterion, and zero-sequence overvoltage protection action criterion. The first predetermined voltage can be based on the rated phase voltage of the low-voltage side bus. U n Set it, for example, to 0.2. U n When the phase voltage at the installation point of the low-voltage side bus voltage transformer U <0.2 U n When the residual voltage on the busbar does not affect the reclosing and automatic transfer switching operations, the device will not operate; when U >0.2 U n At this time, it affects the reclosing or automatic transfer switch operation logic, causing the device to operate.

[0022] When the action logic is a line fault and does not meet the action logic of the conventional disconnection function, it is determined whether there is line protection. If there is line protection, an action command is sent when both the line protection action signal and the line circuit breaker change signal are received simultaneously. If there is no line protection, when the line fault is a permanent fault, an action command is sent through the power direction discrimination element. When the line fault is a transient fault, it is determined whether the fault current at the installation point of the low-voltage side feeder line protection is less than the rated current and whether the phase voltage at the installation point of the current transformer on the low-voltage side undervoltage bus is greater than the second predetermined voltage. If these conditions are met, an action command is sent; otherwise, no action command is sent. In this embodiment, the second predetermined voltage can be based on the rated phase voltage of the low-voltage side bus. U n Set it, for example, to 0.7. U n The predetermined current can be based on the rated current at the installation location of the low-voltage side feeder line protection. I n Set it, for example, to 0.03. I n When the fault current at the installation point of the low-voltage side feeder line protection I From 0.2 I n The above suddenly dropped to 0.03 I n and U >0.7 U n The device operates after a time delay.

[0023] When the action logic is the fault action logic of the high voltage side of the main transformer, it is determined whether the phase voltage at the installation point of the current transformer on the low voltage side undervoltage bus is greater than the third predetermined voltage. If it is greater, an action command is sent; otherwise, no action command is sent. In this embodiment, the third predetermined voltage can be based on the rated phase voltage of the low-voltage side bus. U n Set it, for example, to 0.3. U n ,when U <0.3 U n When the residual voltage of the busbar does not affect the automatic transfer switch operation, the device will not operate; when U >0.3 U n At that time, it affects the automatic switching logic of the backup device, causing the device to operate.

[0024] When the action logic is the fault action logic of the low-voltage side of the main transformer, if the main transformer protection action signal and the low-voltage side circuit breaker change signal are received at the same time, an action command is sent.

[0025] This embodiment, through the above-described action logic, can automatically identify and detect various fault conditions.

[0026] S14. When the action command is sent, the circuit is set to disconnect and the small power supply line on the low-voltage side undervoltage bus is disconnected.

[0027] The fault resolution device in this embodiment is as follows: Figure 3 As shown, in order to completely disconnect the small power supply lines, this embodiment sets up two rounds of disconnection, and disconnects the small power supply lines on the low-voltage side undervoltage bus in the order of the two rounds of disconnection. Specifically, the first round of disconnection is set according to the automatic detection function of the output status of the small power supply lines or a preset interval; the automatic detection function of the output status of the small power supply lines includes using the transformer low-voltage side feeder protection device to collect the power and direction of the small power supply lines, and to determine the power supply status and magnitude of the small power supply lines to the grid; A second round of disconnection is performed on all small power supply lines on the low-voltage side undervoltage bus.

[0028] To restore the disconnected minor power supply line, this embodiment determines that if the phase voltage at the transformer installation point on the low-voltage side undervoltage busbar returns to normal within a preset time and the disconnected minor power supply line is detected to be without voltage, then the disconnected minor power supply line is closed sequentially according to the circuit breaker's open / closed state. This embodiment ensures the safety of the closing operation by closing the circuit breaker only after detecting the lack of voltage in the minor power supply line.

[0029] by Figure 4 Taking the 110kV inner bridge + line transformer main wiring as an example, a specific embodiment of the present invention is as follows: When the fault point is at f1 and one of the following criteria is met: low-frequency action criterion, low-voltage action criterion, over-frequency action criterion, over-voltage action criterion, or zero-sequence over-voltage protection action criterion of the conventional disconnection device, the bus positioning module determines that the low-voltage side section 1 bus is undervoltage based on the current fault bus being bus I, combined with the circuit breaker 1DL closed position, circuit breaker 4DL closed position, and circuit breaker 7DL open position sent by the data acquisition module, and sends this to the logic judgment module; the logic judgment module determines whether to disconnect the small power supply line on section 1 bus based on the undervoltage bus voltage criterion: when U < 0.2Un, the residual voltage of the bus does not affect the reclosing and automatic transfer operation, and the device does not operate; when U > 0.2Un, it affects the reclosing or automatic transfer operation logic, and sends a device operation message to the protection action module; after receiving the message, the protection action module sets up two rounds of disconnection: such as Figure 5 As shown, the first round of disconnection is based on the automatic detection function of the output status of small power supply lines or disconnection at specified intervals; after the first round of disconnection, if the busbar has voltage but has not returned to normal, the second round of disconnection is initiated, disconnecting all small power supply lines on busbar 1; after the voltage returns to normal within the expected time, the disconnected lines are detected to be de-energized, as shown. Figure 6As shown, the protection action module closes and disconnects the small power supply lines in sequence according to the circuit breaker position and the small power supply line Ux criterion sent by the data acquisition module; the small power supply line Ux criterion is to detect that the line is de-energized.

[0030] In another specific embodiment, when the fault point is at f1, and line protection is installed but the conventional disconnection device's low-frequency action criterion, low-voltage action criterion, over-frequency action criterion, over-voltage action criterion, and zero-sequence over-voltage protection action criterion are all not met, the bus positioning module, based on the current faulty bus being bus I, and combined with the circuit breaker 1DL closed, circuit breaker 4DL closed, and circuit breaker 7DL open positions sent by the data acquisition module, determines that the low-voltage side bus section 1 is undervoltage and sends this to the logic judgment module; the logic judgment module, upon simultaneously receiving the line protection action signal and the line circuit breaker position change, sends a device action message to the protection action module; after receiving the message, the protection action module sets up two rounds of disconnection: such as Figure 5 As shown, the first round of disconnection is based on the automatic detection function of the output status of small power supply lines or disconnection at specified intervals; after the first round of disconnection, if the busbar has voltage but has not returned to normal, the second round of disconnection is initiated, disconnecting all small power supply lines on busbar 1; after the voltage returns to normal within the expected time, the disconnected lines are detected to be de-energized, as shown. Figure 6 As shown, the protection action module closes and disconnects the small power supply lines according to the circuit breaker position and small power supply line Ux criterion sequence sent by the data acquisition module. In another specific embodiment, a transient fault occurs at f1. Without additional line protection, the conventional tripping device fails to meet the following criteria: low-frequency operation, low-voltage operation, over-frequency operation, over-voltage operation, and zero-sequence over-voltage protection operation. The busbar location module, based on the current faulty busbar being bus 1, and combined with the circuit breaker 1DL closed, circuit breaker 4DL closed, and circuit breaker 7DL open positions sent by the data acquisition module, determines that a section of the low-voltage side busbar is undervoltage and sends this information to the logic judgment module. The logic judgment module determines that the current suddenly drops from greater than 0.2In to 0.03In, and the voltage is greater than 0.7Un, and activates the delay device. After receiving the message, the protection action module sets up two rounds of tripping: as follows... Figure 5 As shown, the first round of disconnection is based on the automatic detection function of the output status of small power supply lines or disconnection at specified intervals; after the first round of disconnection, if the busbar has voltage but has not returned to normal, the second round of disconnection is initiated, disconnecting all small power supply lines on busbar 1; after the voltage returns to normal within the expected time, the disconnected lines are detected to be de-energized, as shown. Figure 6 As shown, the protection action module closes and disconnects the small power supply lines according to the circuit breaker position and small power supply line Ux criterion sequence sent by the data acquisition module. In another specific embodiment, a fault occurs on the high-voltage side of the main transformer (f2). The bus positioning module, based on the current faulty bus being bus II, and combined with the circuit breaker 2DL (closed), circuit breaker 5DL (open), circuit breaker 6DL (open), and circuit breaker 7DL (open) signals sent by the data acquisition module, determines that two sections of the low-voltage side busbar are undervoltage and sends this information to the logic judgment module. The logic judgment module confirms the fault on the high-voltage side of the main transformer based on the main transformer protection action signal and the high-voltage side voltage being 0. Based on the low-voltage side busbar voltage criterion, when... U <0.3 U n When the residual voltage of the busbar does not affect the automatic transfer switch operation, the device will not operate; when U >0.3 U n When this affects the automatic transfer switch logic, the device sends an action message to the protection action module; upon receiving the message, the protection action module sets up two rounds of disconnection: such as... Figure 5 As shown, the first round of disconnection is based on the automatic detection function of the output status of small power supply lines or disconnection at specified intervals; after the first round of disconnection, if the busbar has voltage but has not returned to normal, the second round of disconnection is initiated, disconnecting all small power supply lines on busbar 1; after the voltage returns to normal within the expected time, the disconnected lines are detected to be de-energized, as shown. Figure 6 As shown, the protection action module closes and disconnects the small power supply lines according to the circuit breaker position and small power supply line Ux criterion sequence sent by the data acquisition module. In another specific embodiment, a low-voltage side fault occurs on bus f3. The bus location module, based on the current faulty bus being bus II, and combined with the data acquisition module's signals of circuit breaker 8DL (closed), circuit breaker 9DL (closed), circuit breaker 10DL (closed), and circuit breaker 6DL (open), determines that the low-voltage side bus sections 2 and 3 are undervoltage and sends this information to the logic judgment module. The logic judgment module, through the main transformer protection action signal and the high-voltage side voltage returning to normal after the protection action, determines that the fault is on the main transformer's low-voltage side. Upon simultaneously receiving the main transformer protection action signal and the low-voltage side circuit breaker position change, it sends a device action message to the protection action module. After receiving the message, the protection action module sets up two rounds of disconnection: such as... Figure 5 As shown, the first round of disconnection is based on the automatic detection function of the output status of small power supply lines or disconnection at specified intervals; after the first round of disconnection, if the busbar has voltage but has not returned to normal, the second round of disconnection is initiated, disconnecting all small power supply lines on busbar 1; after the voltage returns to normal within the expected time, the disconnected lines are detected to be de-energized, as shown. Figure 6 As shown, the protection action module closes and disconnects the small power supply line according to the circuit breaker position and small power supply line Ux criterion sequence sent by the data acquisition module.

[0031] Compared with the prior art, the present invention realizes the functions of automatically determining the bus feeder lines that need to be disconnected under different operating modes, automatically detecting the output status of small power lines, and automatically restoring grid connection after the small power lines are disconnected.

[0032] Based on the above-described distributed power station domain collaborative control and protection method, this invention also provides a distributed power station domain collaborative control and protection system, such as... Figure 7 As shown, the system includes: a data acquisition module 1, a busbar positioning module 2, a logic judgment module 3, and a protection action module 4. The data acquisition module 1 is connected to the busbar positioning module 2, the logic judgment module 3, and the protection action module 4, respectively. The busbar positioning module 2 is connected to the logic judgment module 3, and the logic judgment module 3 is connected to the protection action module 4. The data acquisition module 1 is used to acquire the state data of the power system, which includes at least input quantities, analog quantities, output quantities and MMS network data. The busbar positioning module 2 is used to locate the position of the low-voltage side undervoltage busbar based on the status data. The logic judgment module 3 is used to determine whether to send an action command based on the action logic; the action logic includes line fault and the action logic that meets the conventional disconnection function criteria, line fault and the action logic that does not meet the conventional disconnection function criteria, main transformer high voltage side fault action logic, and main transformer low voltage side fault action logic. The protection action module 4 is used to set up disconnection and disconnect the small power supply line on the low-voltage side undervoltage bus when an action command is sent.

[0033] In another embodiment, the logic judgment module 3 is further configured to: When the action logic is a line fault and meets the action logic of the conventional disconnection function, it is determined whether the phase voltage at the installation point of the current transformer on the low-voltage side undervoltage bus is greater than the first predetermined voltage. If it is greater, an action command is sent; otherwise, no action command is sent. When the action logic is a line fault and does not meet the action logic of the conventional disconnection function, it is determined whether there is line protection. If there is line protection, an action command is sent when both the line protection action signal and the line circuit breaker change signal are received simultaneously. If there is no line protection, when the line fault is a permanent fault, an action command is sent through the power direction discrimination element. When the line fault is a transient fault, it is determined whether the fault current at the installation point of the low-voltage side feeder line protection is less than the rated current and whether the phase voltage at the installation point of the current transformer on the low-voltage side undervoltage bus is greater than the second predetermined voltage. If these conditions are met, an action command is sent; otherwise, no action command is sent. When the action logic is the fault action logic of the high voltage side of the main transformer, it is determined whether the phase voltage at the installation point of the current transformer on the low voltage side undervoltage bus is greater than the third predetermined voltage. If it is greater, an action command is sent; otherwise, no action command is sent. When the action logic is the fault action logic of the low-voltage side of the main transformer, if the main transformer protection action signal and the low-voltage side circuit breaker change signal are received at the same time, an action command is sent.

[0034] In another embodiment, the protection action module 4 is further configured to: When an action command is sent, two rounds of disconnection are set up, and the small power lines on the low-voltage side undervoltage bus are disconnected in the order of the two rounds of disconnection.

[0035] For specific limitations regarding a distributed power station domain collaborative control and protection system, please refer to the limitations of a distributed power station domain collaborative control and protection method described above, which will not be repeated here. Each module in the above system can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the corresponding operations of each module.

[0036] In summary, this invention provides a distributed power station domain collaborative control and protection method and system. It collects state data of the power system; locates the position of the low-voltage side undervoltage bus based on the state data; and determines whether to send an action command based on action logic. The action logic includes action logic for line faults meeting the conventional disconnection function criteria, action logic for line faults not meeting the conventional disconnection function criteria, action logic for main transformer high-voltage side faults, and action logic for main transformer low-voltage side faults. When an action command is sent, disconnection is initiated, and the small power supply lines on the low-voltage side undervoltage bus are disconnected. This invention can automatically determine the bus feeder lines that need to be disconnected under different operating modes, automatically detect the output status of small power supply lines, and automatically restore grid connection after the small power supply lines are disconnected.

[0037] The various embodiments in this specification are described in a progressive manner. For directly identical or similar parts of the embodiments, refer to each other. Each embodiment focuses on its differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. It should be noted that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification.

[0038] The embodiments described above are merely preferred embodiments of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various improvements and substitutions without departing from the technical principles of this invention, and these improvements and substitutions should also be considered within the scope of protection of this application. Therefore, the scope of protection of this patent application should be determined by the scope of the claims.

Claims

1. A distributed power station domain collaborative control and protection method, characterized in that, The method includes: Collect state data of the power system, which includes at least input quantities, analog quantities, output quantities, and MMS network data; The location of the low-voltage side undervoltage busbar is determined based on the aforementioned status data. Based on the action logic, it is determined whether to send an action command; the action logic includes action logic for line faults that meet the criteria for conventional disconnection function, action logic for line faults that do not meet the criteria for conventional disconnection function, action logic for high-voltage side faults of main transformers, and action logic for low-voltage side faults of main transformers. When the action command is sent, the disconnection is set and the small power supply line on the low-voltage side undervoltage bus is disconnected; The step of determining whether to send an action command based on the action logic includes: When the action logic is a line fault and meets the action logic of the conventional disconnection function, it is determined whether the phase voltage at the installation point of the current transformer on the low-voltage side undervoltage bus is greater than the first predetermined voltage. If it is greater, an action command is sent; otherwise, no action command is sent. When the action logic is a line fault and does not meet the action logic of the conventional disconnection function, it is determined whether there is line protection. If there is line protection, an action command is sent when both the line protection action signal and the line circuit breaker change signal are received simultaneously. If there is no line protection, when the line fault is a permanent fault, an action command is sent through the power direction discrimination element. When the line fault is a transient fault, it is determined whether the fault current at the installation point of the low-voltage side feeder line protection is less than the rated current and whether the phase voltage at the installation point of the current transformer on the low-voltage side undervoltage bus is greater than the second predetermined voltage. If these conditions are met, an action command is sent; otherwise, no action command is sent. When the action logic is the fault action logic of the high voltage side of the main transformer, it is determined whether the phase voltage at the installation point of the current transformer on the low voltage side undervoltage bus is greater than the third predetermined voltage. If it is greater, an action command is sent; otherwise, no action command is sent. The first predetermined voltage, the second predetermined voltage and the third predetermined voltage are set according to the rated phase voltage of the low voltage side bus. When the action logic is the fault action logic of the low-voltage side of the main transformer, if the main transformer protection action signal and the low-voltage side circuit breaker change signal are received at the same time, an action command is sent. When an action command is sent, setting up disconnection and cutting off the small power lines on the low-voltage side undervoltage bus includes: When an action command is sent, two rounds of disconnection are set up, and the small power lines on the low-voltage side undervoltage bus are disconnected in the order of the two rounds of disconnection. When an action command is sent, setting up two rounds of disconnection and cutting off the small power lines on the low-voltage side undervoltage bus in the order of the two rounds of disconnection includes: The first round of disconnection is set according to the automatic detection function of the output status of the small power line or the preset interval; the automatic detection function of the output status of the small power line includes using the transformer low-voltage side feeder protection device to collect the power and direction of the small power line, and to determine the power supply status and magnitude of the small power line to the grid. A second round of disconnection is performed on all small power supply lines on the low-voltage side undervoltage bus.

2. The distributed power station domain collaborative control and protection method according to claim 1, characterized in that, The step of locating the position of the low-voltage side undervoltage bus based on the state data further includes: Based on the circuit breaker's open / closed status, locate the section on the low-voltage side undervoltage busbar where the low-voltage side undervoltage fault occurred.

3. The distributed power station domain collaborative control and protection method according to claim 2, characterized in that, When an action command is sent, after setting up disconnection and cutting off the small power lines on the low-voltage side undervoltage bus, the following steps are included: If the phase voltage at the transformer installation point on the low-voltage side undervoltage busbar returns to normal within a preset time and the disconnected small power supply line is detected to be without voltage, then the disconnected small power supply line is closed sequentially according to the circuit breaker's open / closed state.

4. A distributed power station domain collaborative control and protection system, characterized in that, The system includes: a data acquisition module, a busbar positioning module, a logic judgment module, and a protection action module. The data acquisition module is connected to the busbar positioning module, the logic judgment module, and the protection action module, respectively. The busbar positioning module is connected to the logic judgment module, and the logic judgment module is connected to the protection action module. The data acquisition module is used to acquire state data of the power system, which includes at least input quantities, analog quantities, output quantities and MMS network data. The busbar positioning module is used to locate the position of the low-voltage side undervoltage busbar based on the status data. The logic judgment module is used to determine whether to send an action command based on the action logic; the action logic includes action logic for line faults that meet the criteria for conventional disconnection function, action logic for line faults that do not meet the criteria for conventional disconnection function, action logic for high-voltage side faults of the main transformer, and action logic for low-voltage side faults of the main transformer. The protection action module is used to set up disconnection and disconnect the small power supply line on the low-voltage side undervoltage bus when an action command is sent. The logic judgment module is also used for: When the action logic indicates a line fault and meets the conventional tripping function criteria, it determines whether the phase voltage at the installation point of the current transformer on the low-voltage side undervoltage busbar is greater than a first predetermined voltage. If it is greater, an action command is sent; otherwise, no action command is sent. When the action logic indicates a line fault but does not meet the conventional tripping function criteria, it determines whether line protection exists. If line protection exists, an action command is sent when both a line protection action signal and a line circuit breaker position change signal are received simultaneously. If no line protection exists, an action command is sent via the power direction discrimination element when the line fault is a permanent fault. In the event of a transient fault, it is determined whether the fault current at the low-voltage side feeder line protection installation point is less than the rated current and whether the phase voltage at the instrument transformer installation point on the low-voltage side undervoltage busbar is greater than the second predetermined voltage. If these conditions are met, an action command is sent; otherwise, no action command is sent. When the action logic is the main transformer high-voltage side fault action logic, it is determined whether the phase voltage at the instrument transformer installation point on the low-voltage side undervoltage busbar is greater than the third predetermined voltage. If this is greater, an action command is sent; otherwise, no action command is sent. When the action logic is the main transformer low-voltage side fault action logic, if both the main transformer protection action signal and the low-voltage side circuit breaker position change signal are received simultaneously, an action command is sent. The protection action module is also used for: When an action command is sent, two rounds of disconnection are set up, and the small power lines on the low-voltage side undervoltage bus are disconnected in the order of the two rounds of disconnection.

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