Grid connection method and device of new energy station, readable storage medium and processor

Abstract

The invention discloses a grid connection method and device of a new energy station, a readable storage medium and a processor, and relates to the technical field of power control. The method comprises the steps that in response to a fault event of a new energy station, a fault repair result of the new energy station is determined, and the fault repair result comprises fault repair success or fault repair failure; in response to the fact that the fault repair result is successful in fault repair, determining a to-be-connected-grid state of the new energy station, the to-be-connected-grid state including a to-be-connected-grid normal state or a to-be-connected-grid abnormal state; in response to the to-be-grid-connected state being a to-be-grid-connected normal state, a grid-connected strategy of the new energy station is determined, and the grid-connected strategy is used for indicating a grid-connected rule of the new energy station; and performing grid connection on the new energy station according to the grid connection strategy. According to the invention, the technical problem of low grid connection efficiency after the fault of the new energy station is removed is solved.

Description

Technical Field

[0001] The present invention relates to the field of power control technology, and in particular to a grid-connected method, device, readable storage medium and processor for a new energy station. Background Art

[0002] At present, with the increasing severity of the global energy crisis and the increasing severity of environmental pollution and climate change, the development and utilization of new energy has become an important direction of the global energy strategy. New energy, especially renewable energy such as wind and solar energy, has received great attention from the world because of its clean, pollution-free and sustainable characteristics. However, the power generation characteristics of new energy are highly unstable and unpredictable. Especially when encountering faults, the grid-connected system of new energy may have problems such as frequent disconnection and power oscillation. Under the premise of ensuring the safety of the power grid, the rapid recovery and grid connection of new energy stations can be achieved. This can not only improve the utilization rate of new energy power generation and reduce the power generation loss caused by faults, but also enhance the power grid's ability to absorb new energy power generation and improve the operating efficiency of the entire new energy station. After the fault is eliminated, how to quickly achieve reconnection to the grid to reduce power outage time and reduce economic losses is a major challenge in the operation of new energy stations.

[0003] In the related technologies, new energy needs to be manually reconnected to the grid after the fault is removed, and the manual operation of the grid connection process takes a long time, and a large amount of power generation benefits will be lost under the condition of instantaneous fault of the grid connection line. Therefore, there is a technical problem of low grid connection efficiency after the fault of the new energy station is eliminated.

[0004] With regard to the technical problem of low grid-connection efficiency after the fault of the new energy station is resolved, no effective solution has been proposed so far. Summary of the invention

[0005] Embodiments of the present invention provide a method, device, readable storage medium and processor for connecting a new energy station to the grid, so as to at least solve the technical problem of low grid connection efficiency after the fault of the new energy station is resolved.

[0006] According to one aspect of an embodiment of the present invention, a method for connecting a new energy station to the grid is provided. The method may include: in response to a fault event occurring in the new energy station, determining a fault repair result of the new energy station, wherein the fault repair result includes a successful fault repair or a failed fault repair; in response to the fault repair result being a successful fault repair, determining a state of the new energy station to be connected to the grid, wherein the state of the new energy station to be connected to the grid includes a normal state of the new energy station to be connected to the grid, or an abnormal state of the new energy station to be connected to the grid; in response to the state of the new energy station to be connected to the grid being a normal state of the new energy station to be connected to the grid, determining a grid connection strategy for the new energy station, wherein the grid connection strategy is used to indicate a rule for connecting the new energy station to the grid; and connecting the new energy station to the grid according to the grid connection strategy.

[0007] Optionally, in response to the fault repair result being that the fault is repaired successfully, the grid-connected state of the new energy station is determined, including: in response to the fault repair result being that the fault is repaired successfully, respectively obtaining the voltage states of the high-voltage side bus and the low-voltage side bus in the new energy station, wherein the voltage state includes a voltage state or a no-voltage state; in response to the voltage state of the high-voltage side bus being a no-voltage state, or the voltage state of the low-voltage side bus being a voltage state, determining that the grid-connected state of the new energy station is an abnormal grid-connected state; in response to the voltage state of the high-voltage side bus being a voltage state, and the voltage state of the low-voltage side bus being a no-voltage state, determining that the grid-connected state of the new energy station is a normal grid-connected state.

[0008] Optionally, in response to the state of being connected to the grid being a normal state of being connected to the grid, determining the grid connection strategy of the new energy station, including: in response to the state of being connected to the grid being a normal state of being connected to the grid, identifying the lines to be connected to the grid in the new energy station; based on the lines to be connected to the grid, determining the grid connection strategy of the new energy station.

[0009] Optionally, based on the line to be connected to the grid, the grid-connection strategy of the new energy station is determined, including: obtaining the connection status of the line to be connected to the grid and the low-voltage side bus, wherein the connection status includes a normal connection status and an abnormal connection status; in response to the connection status being an abnormal connection status, determining the grid-connection strategy of the new energy station; in response to the connection status being a normal connection status, ending the grid-connection process of the new energy station.

[0010] Optionally, in response to a fault at the new energy station, determining a fault repair result of the new energy station includes: in response to a fault at the new energy station, obtaining a fault type of the fault; and in response to the fault type being a transient fault, determining a fault repair result of the fault.

[0011] Optionally, the grid-connection method of the new energy station further includes: in response to the state to be connected to the grid being an abnormal state, ending the grid-connection process of the new energy station.

[0012] According to another aspect of an embodiment of the present invention, a grid-connected device for a new energy station is also provided. The device may include: a first determination unit, for determining the fault repair result of the new energy station in response to a fault event occurring in the new energy station, wherein the fault repair result includes a successful fault repair or a failed fault repair; a second determination unit, for determining the grid-connected state of the new energy station in response to the fault repair result being a successful fault repair, wherein the grid-connected state includes a normal grid-connected state or an abnormal grid-connected state; a third determination unit, for determining the grid-connected strategy of the new energy station in response to the grid-connected state being a normal grid-connected state, wherein the grid-connected strategy is used to indicate the rules for grid-connecting the new energy station; and a grid-connected unit, for grid-connecting the new energy station according to the grid-connected strategy.

[0013] According to another aspect of an embodiment of the present invention, a computer-readable storage medium is also provided, which includes a stored program, wherein when the program is executed by a processor, the device where the storage medium is located is controlled to execute the grid-connected method of the new energy station in the embodiment of the present invention.

[0014] According to another aspect of an embodiment of the present invention, a processor is further provided, wherein the processor is used to run a program, wherein when the program is run, the method for connecting to the grid of a new energy station in an embodiment of the present invention is executed.

[0015] According to another aspect of the embodiments of the present invention, a computer program product is provided, which includes computer instructions, and when the computer instructions are executed by a processor, the method for connecting to the grid of a new energy station in the embodiments of the present invention is implemented.

[0016] In an embodiment of the present invention, in response to a fault event occurring in a new energy station, a fault repair result of the new energy station is determined, wherein the fault repair result includes a successful fault repair or a failed fault repair; in response to the fault repair result being a successful fault repair, the grid-connected state of the new energy station is determined, wherein the grid-connected state includes a normal grid-connected state or an abnormal grid-connected state; in response to the grid-connected state being a normal grid-connected state, a grid-connected strategy of the new energy station is determined, wherein the grid-connected strategy is used to indicate a rule for grid-connecting the new energy station; and the new energy station is grid-connected according to the grid-connected strategy. That is, the present invention determines the grid-connected state of the new energy station after the fault is repaired, determines the grid-connected strategy according to the grid-connected state, and then grid-connects the busbar and the collector on the busbar in the new energy station according to the grid-connected strategy, thereby solving the technical problem of low grid-connected efficiency after the fault of the new energy station is cleared, and achieving the technical effect of improving the grid-connected efficiency after the fault of the new energy station is cleared. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 is a flow chart of a grid-connected method for a new energy station according to an embodiment of the present invention;

[0019] Figure 2 This is a flow chart of a method for rapid grid connection step by step after a new energy station is disconnected according to an embodiment of the present invention;

[0020] Figure 3 It is a flowchart of a preferred solution of a method for rapid grid connection step by step after a new energy station is disconnected according to an embodiment of the present invention;

[0021] Figure 4is a schematic diagram of a main connection of a busbar connection new energy station according to an embodiment of the present invention;

[0022] Figure 5 is a schematic diagram of a key grid-connection process according to an embodiment of the present invention;

[0023] Figure 6 It is a schematic diagram of a grid-connected device for a new energy station according to an embodiment of the present invention. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0025] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, functional component or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, functional components or devices.

[0026] According to an embodiment of the present invention, an embodiment of a method for connecting a new energy station to the grid is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0027] Figure 1 is a flow chart of a method for connecting a new energy station to the grid according to an embodiment of the present invention. Figure 1 As shown, the method may include the following steps:

[0028] Step S101, in response to a fault event occurring at a new energy station, determining a fault repair result of the new energy station.

[0029] In the technical solution provided in the above step S101 of the present invention, the fault repair result includes a successful repair of the fault or a failed repair of the fault.

[0030] In this embodiment, when a fault occurs in the new energy station, a fault repair result of the new energy station is determined, wherein the fault repair result may also be referred to as a fault disconnection result.

[0031] Optionally, when a fault occurs in the new energy station, the fault type is obtained, wherein the fault type may be a transient fault (transient fault) or a permanent fault (permanent fault).

[0032] Optionally, after determining the fault type, when the fault type is a transient fault, a fault repair result of the fault is determined.

[0033] Step S102, in response to the fault repair result being that the fault is repaired successfully, determining the grid-connection state of the new energy station.

[0034] In the technical solution provided in the above step S102 of the present invention, the state to be connected to the grid includes a normal state to be connected to the grid, or an abnormal state to be connected to the grid.

[0035] In this embodiment, after the fault repair result of the new energy station is determined in step S101, when the fault repair result is that the fault is repaired successfully, the grid-connection state of the new energy station is determined.

[0036] Optionally, when the fault repair result is that the fault is repaired successfully, the voltage states of the high-voltage side bus and the low-voltage side bus in the new energy station are obtained respectively, wherein the voltage state includes a voltage state or a no-voltage state.

[0037] Optionally, when the voltage state of the high-voltage side bus is a no-voltage state, or the voltage state of the low-voltage side bus is a voltage state, it means that some inverter protections have failed to operate and the bus does not meet the conditions for grid connection. Based on this, it can be determined that the grid-connected state of the new energy station is an abnormal grid-connected state.

[0038] For example, if the bus voltage on the faulty high-voltage side is in an unrecovered state, that is, a no-voltage state, within the predetermined time period when the grid-connection function is opened, the grid-connection process is terminated, that is, the grid-connection state of the new energy station is determined to be an abnormal grid-connection state.

[0039] Optionally, when the voltage state of the high-voltage side bus is in a voltage state and the voltage state of the low-voltage side bus is in a no-voltage state, it means that the bus has the conditions for grid connection. Based on this, it can be determined that the grid-connected state of the new energy station is a normal state for grid connection.

[0040] For example, in the process of manual grid connection, in order to reduce the impact on the power grid and equipment, the order of high voltage first and low voltage later is generally followed to connect to the grid step by step. When the grid connection line fails, the line protection and new energy photovoltaic inverter protection are first activated. If the low-voltage side bus has no pressure at this time, the bus has the conditions for grid connection, that is, it can be determined that the grid connection state of the new energy station is the normal state of grid connection, and an order is issued to disconnect the collector side circuit breaker on it to prepare for the bus connection to the grid.

[0041] Step S103, in response to the state to be connected to the grid being the normal state to be connected to the grid, determining the grid connection strategy of the new energy station.

[0042] In the technical solution provided in the above step S103 of the present invention, the grid connection strategy is used to indicate the rules for connecting the new energy station to the grid.

[0043] In this embodiment, after the waiting-for-grid-connection state of the new energy station is determined in step S102, when the waiting-for-grid-connection state is the waiting-for-grid-connection normal state, the grid-connection strategy of the new energy station is determined.

[0044] Optionally, when the state to be connected to the grid is the normal state to be connected to the grid, the line to be connected to the grid in the new energy station is identified. The line to be connected to the grid can also be called a collector line that meets the conditions for grid connection.

[0045] Optionally, the connection status of the line to be connected to the grid and the low-voltage side bus is obtained, wherein the connection status includes a normal connection status and an abnormal connection status; when the connection status is an abnormal connection status, the grid connection strategy of the new energy station is determined.

[0046] Optionally, when the connection state is an abnormal connection state, it indicates that the low-voltage side bus is disconnected from the collector, that is, all collectors on the low-voltage side bus that loses pressure are disconnected.

[0047] For example, when the collector switches on the low-voltage side bus are all tripped and the grounding transformer / station transformer switch and the neutral point position on the bus are both closed, determine the grid-connected strategy for the bus in the new energy station.

[0048] Optionally, when the connection status is a normal connection status, the grid connection process of the new energy station is ended.

[0049] Step S104, connecting the new energy station to the grid according to the grid connection strategy.

[0050] In the technical solution provided in the above step S104 of the present invention, after the grid connection strategy of the new energy station is determined in step S103, the new energy station is connected to the grid according to the grid connection strategy.

[0051] In this embodiment, the busbar in the new energy station is connected to the grid according to the grid connection strategy. After the busbar is connected to the grid, the collector on the busbar is connected to the grid.

[0052] For example, the main transformers / busbars are grouped and one group of main transformers / busbars is connected to the grid each time until the whole station is connected to the grid.

[0053] It should be noted that the above embodiments can be implemented through the grid-connected device of the new energy station.

[0054] In the above steps S101 to S104 of the present invention, in response to a fault event occurring in a new energy station, the fault repair result of the new energy station is determined, wherein the fault repair result includes a successful fault repair or a failed fault repair; in response to the fault repair result being a successful fault repair, the state to be connected to the grid of the new energy station is determined, wherein the state to be connected to the grid includes a normal state to be connected to the grid, or an abnormal state to be connected to the grid; in response to the state to be connected to the grid being a normal state to be connected to the grid, the grid connection strategy of the new energy station is determined, wherein the grid connection strategy is used to indicate the rules for connecting the new energy station to the grid; and the new energy station is connected to the grid according to the grid connection strategy. That is to say, the present invention determines the state to be connected to the grid of the new energy station after the fault is repaired, determines the grid connection strategy according to the state to be connected to the grid, and then connects the busbar in the new energy station and the collector on the busbar according to the grid connection strategy, thereby solving the technical problem of low grid connection efficiency after the fault of the new energy station is eliminated, and achieving the technical effect of improving the grid connection efficiency after the fault of the new energy station is eliminated.

[0055] The above method of this embodiment is further introduced below.

[0056] As an optional implementation method, in response to the fault repair result being a successful fault repair, determining the grid-connected state of the new energy station includes: in response to the fault repair result being a successful fault repair, respectively obtaining the voltage states of the high-voltage side bus and the low-voltage side bus in the new energy station, wherein the voltage state includes a voltage state or a no-voltage state; in response to the voltage state of the high-voltage side bus being a no-voltage state, or the voltage state of the low-voltage side bus being a voltage state, determining that the grid-connected state of the new energy station is an abnormal grid-connected state; in response to the voltage state of the high-voltage side bus being a voltage state, and the voltage state of the low-voltage side bus being a no-voltage state, determining that the grid-connected state of the new energy station is a normal grid-connected state.

[0057] In this embodiment, when the fault repair result is that the fault is repaired successfully, the voltage states of the high-voltage side bus and the low-voltage side bus in the new energy station are respectively obtained.

[0058] Optionally, when the voltage state of the high-voltage side bus is a no-voltage state, or the voltage state of the low-voltage side bus is a voltage state, the grid-connected state of the new energy station is determined to be an abnormal grid-connected state; when the voltage state of the high-voltage side bus is a voltage state, and the voltage state of the low-voltage side bus is a no-voltage state, the grid-connected state of the new energy station is determined to be a normal grid-connected state.

[0059] Optionally, the state to be connected to the grid is determined in advance, so as to avoid the personal and equipment safety risks caused by the device starting automatic grid connection during manual grid connection after a permanent fault.

[0060] As an optional implementation method, in response to the state of being connected to the grid being the normal state of being connected to the grid, determining the grid connection strategy of the new energy station, including: in response to the state of being connected to the grid being the normal state of being connected to the grid, identifying the lines to be connected to the grid in the new energy station; based on the lines to be connected to the grid, determining the grid connection strategy of the new energy station.

[0061] In this embodiment, when the state to be connected to the grid is the normal state to be connected to the grid, the lines to be connected to the grid in the new energy station are identified; according to the lines to be connected to the grid, the grid connection strategy of the new energy station is determined. The lines to be connected to the grid may also be collector lines. That is, when the state to be connected to the grid is the normal state to be connected to the grid, the collector lines that meet the grid connection conditions are identified.

[0062] Optionally, by identifying the lines to be connected to the grid, the grid connection strategy of the new energy station can be determined according to the specific conditions of the lines, including the grid connection time, grid connection method, etc., to ensure that the station is smoothly connected to the power grid.

[0063] As an optional implementation method, based on the line to be connected to the grid, the grid-connection strategy of the new energy station is determined, including: obtaining the connection status of the line to be connected to the grid and the low-voltage side bus, wherein the connection status includes a normal connection status and an abnormal connection status; in response to the connection status being an abnormal connection status, determining the grid-connection strategy of the new energy station; in response to the connection status being a normal connection status, ending the grid-connection process of the new energy station.

[0064] In this embodiment, the connection status of the line to be connected to the grid and the low-voltage side bus is obtained. When the connection status is an abnormal connection state, the grid connection strategy of the new energy station is determined; when the connection status is a normal connection state, the grid connection process of the new energy station is ended.

[0065] For example, when the bus is ready for grid connection, the collector circuit breaker on it is disconnected to prepare for the bus grid connection. That is, the connection mode between the collector on the bus and the bus is determined, and when the connection state is abnormal, the grid connection strategy of the new energy station is determined.

[0066] As an optional implementation method, in response to a fault at a new energy station, determining a fault repair result of the new energy station includes: in response to a fault at the new energy station, obtaining the fault type of the fault; in response to the fault type being a transient fault, determining the fault repair result of the fault.

[0067] In this embodiment, when a fault occurs in the new energy station, the fault type is obtained; when the fault type is a transient fault, the fault repair result of the fault is determined.

[0068] Optionally, in the power system, the probability of instantaneous faults is relatively high, even reaching 70% to 80% of line faults. After a transient fault occurs, the line reclosing switch operates and the circuit breaker recloses successfully, which will not cause a long-term power outage. Considering the longest time for line reclosing, the reclosing should also be completed within 10 seconds to restore the bus voltage. Therefore, in practical applications, the duration of the open grid-connection function should not be too long. It is recommended to set it to 15 seconds to avoid personal and equipment safety risks caused by the device starting automatic grid connection during manual grid connection after permanent faults.

[0069] As an optional implementation manner, the grid-connection method of the new energy station further includes: in response to the state to be connected to the grid being an abnormal state, ending the grid-connection process of the new energy station.

[0070] In this embodiment, when the state to be connected to the grid is an abnormal state, it means that the busbar does not meet the grid connection conditions. Based on this, the grid connection process of the new energy station is terminated.

[0071] It should be noted that the above embodiments can be implemented through the grid-connected device of the new energy station.

[0072] In this embodiment, in response to a fault event at a new energy station, the fault repair result of the new energy station is determined, wherein the fault repair result includes a successful fault repair or a failed fault repair; in response to the fault repair result being a successful fault repair, the grid-connected state of the new energy station is determined, wherein the grid-connected state includes a normal grid-connected state or an abnormal grid-connected state; in response to the grid-connected state being a normal grid-connected state, the grid-connected strategy of the new energy station is determined, wherein the grid-connected strategy is used to indicate the rules for grid-connecting the new energy station; and the new energy station is grid-connected according to the grid-connected strategy. That is, the present invention determines the grid-connected state of the new energy station after the fault is repaired, determines the grid-connected strategy according to the grid-connected state, and then grid-connects the busbar and the collector on the busbar in the new energy station according to the grid-connected strategy, thereby solving the technical problem of low grid-connected efficiency after the fault of the new energy station is removed, and achieving the technical effect of improving the grid-connected efficiency after the fault of the new energy station is removed.

[0073] The technical solution of the embodiment of the present invention is illustrated below in conjunction with preferred implementation modes.

[0074] At present, with the increasing severity of the global energy crisis and the increasing severity of environmental pollution and climate change, the development and utilization of new energy has become an important direction of the global energy strategy. New energy, especially renewable energy such as wind and solar energy, has received great attention from the world because of its clean, pollution-free and sustainable characteristics. However, the power generation characteristics of new energy are highly unstable and unpredictable. Especially when encountering faults, the grid-connected system of new energy may have problems such as frequent disconnection and power oscillation. Under the premise of ensuring the safety of the power grid, the rapid recovery and grid connection of new energy stations can be achieved. This can not only improve the utilization rate of new energy power generation and reduce the power generation loss caused by faults, but also enhance the power grid's ability to absorb new energy power generation and improve the operating efficiency of the entire new energy station. After the fault is eliminated, how to quickly achieve reconnection to the grid to reduce power outage time and reduce economic losses is a major challenge in the operation of new energy stations.

[0075] In the related technologies, new energy needs to be manually reconnected to the grid after the fault is removed, and the manual operation of the grid connection process takes a long time, and a large amount of power generation benefits will be lost under the condition of instantaneous fault of the grid connection line. Therefore, there is a technical problem of low grid connection efficiency after the fault of the new energy station is eliminated. There is no effective solution to the above technical problem of low grid connection efficiency after the fault of the new energy station is eliminated.

[0076] However, the embodiment of the present invention proposes a method for rapid grid connection step by step after the new energy station is disconnected. When the instantaneous fault protection of the grid-connected line is successfully reclosed and the voltage of the high-voltage side bus is restored, the collector line that meets the grid connection conditions is automatically identified and the electrical connection with the low-voltage side bus is disconnected. Then, the low-voltage side of the main transformer and the collector line are reclosed in a certain order to achieve rapid grid connection. This method can replace manual operation after the single instantaneous fault protection reclosing of the grid-connected line is successful, thereby solving the technical problem of low grid connection efficiency after the fault of the new energy station is eliminated, and achieving the technical effect of improving the grid connection efficiency after the fault of the new energy station is eliminated.

[0077] The embodiments of the present invention are further described below.

[0078] Figure 2 The flowchart of a method for rapid grid connection step by step after a new energy station is disconnected according to an embodiment of the present invention, the grid connection method comprises the following steps:

[0079] Step S201, detecting a fault in the grid-connected line of a new energy station, and cutting off the new energy station from becoming low and SVG.

[0080] In this embodiment, common faults in the new energy station are identified and the power supply line is isolated from the main grid. Among them, cutting off the low voltage side circuit breaker of the main transformer of the new energy station refers to disconnecting the circuit breaker of the low voltage side of the main transformer of the new energy station, and cutting off the SVG refers to disconnecting the SVG circuit breaker of the new energy station.

[0081] Step S202, the single-instantaneous fault is eliminated, the protection reclosing is successful, and the high-voltage side bus voltage is restored.

[0082] In this embodiment, the instantaneous fault is eliminated, the protection reclosing is successful, and it is determined that the high-voltage side bus voltage is restored.

[0083] Optionally, in the grid-connected lines of new energy stations, the probability of instantaneous faults is relatively high, even reaching 70% to 80% of line faults. After a transient fault occurs, the line reclosing switch operates and the circuit breaker recloses successfully, which will not cause a long power outage on the line. Considering the longest time taken for line reclosing, the reclosing should also be completed within 10 seconds to restore the bus voltage. Therefore, in practical applications, the duration of the open grid-connected function should not be too long. It is recommended to set it to 15 seconds to avoid personal and equipment safety risks caused by the device starting automatic grid-connected during manual grid-connected operation after a permanent fault.

[0084] Step S203, identifying a collector line that meets the grid connection conditions.

[0085] In this embodiment, a collector line that meets the grid connection conditions is identified to prepare for busbar grid connection.

[0086] Optionally, in the process of manual grid connection, in order to reduce the impact on the power grid and equipment, the order of high voltage first and low voltage later is generally followed to connect to the grid step by step. When the grid connection line fails, the line protection and new energy photovoltaic inverter protection are first activated. If the low-voltage side busbar still has pressure at this time, it means that some inverter protections have failed to operate, and the busbar does not meet the grid connection conditions; on the contrary, if the low-voltage side busbar has no pressure at this time, the busbar meets the grid connection conditions, and an order is issued to disconnect the collector side circuit breaker on it to prepare for the busbar grid connection.

[0087] Step S204, connecting the low voltage side busbar to the grid.

[0088] In this embodiment, for the low-voltage side busbar that meets the grid-connected conditions, when the collector switches on the low-voltage side busbar are all tripped and the grounding transformer / station transformer switch and the neutral point position on the busbar are all in the closed position, a command is issued to close the low-voltage side switch of the main transformer corresponding to the busbar, and it is detected whether its voltage is restored, thereby completing the grid-connected operation of the low-voltage side busbar.

[0089] Step S205, connecting the collector line on the low-voltage side busbar of the grid.

[0090] In this embodiment, the grid connection of the collector line on the grid-connected busbar is carried out to prevent the collector line switch from closing due to a fault or the collector line overcurrent protection from being activated when the box-type transformer is charging. A strategy of closing the switches one by one at intervals of 1 second is adopted during the grid connection process of the collector line.

[0091] Step S206, complete the whole station grid connection.

[0092] In this embodiment, all buses and collectors to be connected to the grid are connected to the grid. To ensure the safety of equipment during the grid connection process and prevent the problem of being unable to distinguish faulty equipment due to simultaneous grid connection of different buses, the main transformers / busbars are grouped and one group of main transformers / busbars is connected to the grid each time until the whole station is connected to the grid.

[0093] In this embodiment, when a system fault is detected, the SVG switch connected to the low-voltage side of the main transformer and the low-voltage bus is tripped. When the grid-connected line instantaneous fault protection is successfully reclosed and the high-voltage bus voltage is restored, all collectors on the low-voltage bus that has lost voltage are de-energized. After that, when the station transformer / grounding transformer switch and the neutral point switch are in the closed position, the low-voltage side of the main transformer is closed. If the low-voltage bus voltage is restored, the collector switches are closed one by one at specific intervals.

[0094] Optionally, a system for rapid step-by-step grid-connection after a new energy station is decoupled may include: collecting the three-phase voltage of the high-voltage side bus, the open triangle voltage, the line voltage and three-phase current of the grid-connected line, and the three-phase voltage of the low-voltage side bus; collecting the circuit breaker position signals of the grid-connected line, the high-voltage side of the main transformer, the low-voltage side of the main transformer, the collector line and the SVG trolley, the circuit breaker position signal of the grounding transformer or station transformer, the neutral point switch position signal, and the collector line closing position signal; connecting to the low-voltage side of the main transformer, the collector line tripping / closing circuit, and the SVG tripping circuit.

[0095] Figure 3 This is a flowchart of a preferred solution of a method for rapid grid connection step by step after a new energy station is disconnected according to an embodiment of the present invention. The grid connection method includes the following steps:

[0096] Step S301, whether the fault disconnection criterion is met.

[0097] In this embodiment, it is determined whether the fault tripping criterion is met. If so, step S302 is executed; if not, the process ends.

[0098] Step S302, cutting off the low-voltage side switch of the main transformer and the SVG switch.

[0099] In this embodiment, the fault disconnection and removal becomes low or SVG during the switch tripping waiting delay time Tt. As a preferred solution, Tt can be 0.3s.

[0100] Step S303, whether both the low and SVG are tripped.

[0101] In this embodiment, it is determined whether both the low and SVG are tripped. If both are tripped, step S304 is executed. If neither is tripped, the process ends.

[0102] Step S304: Check whether the high-voltage side bus is restored.

[0103] In this embodiment, during the time period Tbw when the grid-connection function is open, it is determined whether the high-voltage side bus is restored. If restored, step S305 is executed. If not restored, the process ends.

[0104] Optionally, if the bus voltage on the fault high-voltage side is not restored within the grid-connection function opening time Tbw, the grid-connection process is terminated. If the voltage of any line of the fault high-voltage side bus is greater than the bus voltage recovery set value Uyy for the bus voltage recovery confirmation delay Tyy, the next step is entered.

[0105] Optionally, as a preferred solution, after the decoupling action, Tbw can be 15s, Uyy can be 0.7 times the rated voltage, and Tyy can be 1s.

[0106] Step S305, whether there is a low-voltage busbar with pressure loss.

[0107] In this embodiment, it is determined whether there is a low-voltage busbar with depressurization. If so, step S306 is executed; if not, the process ends.

[0108] Optionally, the state of the low-voltage side busbar brought by the fault clearing is judged. If there is no low-voltage side busbar that has pressure before starting and loses pressure after starting, the grid connection process is terminated.

[0109] Step S306, cutting off the collector connected to the low-voltage busbar that has lost pressure.

[0110] In this embodiment, the collector connected to the low-voltage busbar with depressurization is cut off. That is, if there is a low-voltage busbar with depressurization, the collector switch running on it is tripped.

[0111] Step S307, whether all collectors on the low-voltage bus are tripped.

[0112] In this embodiment, it is determined whether all the collectors on the low-voltage side busbar are tripped. If they are tripped, step S308 is executed; if not, step S313 is executed.

[0113] Optionally, if any of the collector switches ordered to be cut off refuses to trip, the low-voltage side busbar will be removed from the grid-connected process; if all the collectors connected to any of the above busbars are tripped, the corresponding state will be marked as pending closing state, and the next step will be entered.

[0114] Step S308, determining whether the closing and grid connection is successful.

[0115] In this embodiment, it is determined whether the closing and grid connection is successful. If the low-voltage side bus voltage recovery information is successfully obtained, if not, step S313 is executed.

[0116] Optionally, a circuit breaker with a smaller sequence number among the circuit breakers to be closed is selected, a closing command is issued, and low-voltage side bus voltage recovery information is obtained.

[0117] Step S309: Check whether the low voltage side bus voltage is restored.

[0118] In this embodiment, it is determined whether the low-voltage side bus voltage is restored within the component closing interval time Tjg during the grid-connected process. If restored, step S310 is executed; if not, step S313 is executed.

[0119] Step S310, merging the collectors on the low-voltage side busbar.

[0120] In this embodiment, the collectors on the low-voltage side busbar are combined, that is, the collectors on the low-voltage side busbar are combined one by one.

[0121] Optionally, if the bus voltage of any phase is greater than the Uyy value and lasts for 200ms during the Tjg time, and the post-acceleration condition is not met during this period, then proceed to the next step. As a preferred solution, Tjg is 1s.

[0122] Step S311, determine whether the grid-connected busbar is overcurrent or the closed collector is tripped.

[0123] In this embodiment, it is determined whether the grid-connected busbar is overcurrent or the closed collector is tripped. If it is tripped, step S314 is executed; if it is not tripped, step S312 is executed.

[0124] Step S312: Whether the total number of closed collectors is less than the number of collectors on the busbar.

[0125] In this embodiment, it is determined whether the total number of closed collectors m is less than the number of collectors on the bus n, that is, it is determined whether all collectors on the bus are closed. If the total number of collectors m is less than the number of collectors on the bus n, step S310 is executed; if the total number of collectors m is not less than the number of collectors on the bus n, step S313 is executed.

[0126] Step S313: whether the number of merged buses is less than the number of main transformers.

[0127] In this embodiment, it is determined whether the number of merged busbars is less than the number of main transformers, that is, it is determined whether all the transformers to be closed and the collectors on their corresponding low-voltage side buses have been connected to the grid. If the number of merged busbars is less than the number of main transformers, step S307 is executed. If the number of merged busbars is not less than the number of main transformers, the process ends.

[0128] Step S314, record the number of tripped collector lines.

[0129] In this embodiment, the number of tripped collector lines is recorded and the grid connection process is ended.

[0130] In this embodiment, in order to avoid the expansion of accidents caused by grid connection at the fault point, the device is configured with the "accelerated cutting after closing the fault" function. In particular, if any of the following conditions are met, the "accelerated cutting after closing the fault" function is opened in Tjg: for the scenario of low-voltage switch closing, if any phase of the fault current is greater than the accelerated cutting current threshold Ihjs1 after the low-voltage switch closing, and the condition is always met until the low-voltage switch closing and fault accelerated cutting delay Thjs1, the low-voltage switch that was closed before is accelerated to trip and the grid connection is terminated. For the scenario of collector closing, if any phase of the fault current is greater than the accelerated cutting current threshold Ihjs2 after the collector closing, and the condition is always met until the collector closing and fault accelerated cutting delay Thjs2, the collector that was closed before is accelerated to trip and the grid connection is terminated. For the scenario of collector closing, if the collector box becomes charged after the scene of collector closing, it may cause the collector overcurrent III stage action. If it is detected that the collector switch that has been connected to the grid changes from closing to opening, the entire grid connection process is stopped.

[0131] In this embodiment, the grid-connected control process of the present invention also includes collecting the closing position and post-closing position signals of the collector. In the non-starting state, it is judged to be a normal state when and only when the closing position and the post-closing position are both 1. In other states, the closing position and the post-closing position signals are inconsistent after a 5s delay, and the grid-connected function is locked.

[0132] The effectiveness of the present invention is verified by comparing the present invention with the traditional method.

[0133] In this embodiment, Table 1 is a comparative diagram of the method of the present invention and the traditional manual grid connection method. As shown in Table 1, the fault disconnection of new energy needs to be configured with a fault disconnection device, and the market price of a single device is about 60,000 yuan; the step-by-step grid connection of new energy currently adopts the method of manual investment and withdrawal, and a single station takes an average of about 2 hours to achieve new energy grid connection and power generation. From Table 1, it can be seen that in terms of construction, the newly developed new energy fault disconnection and fast grid connection device is expected to have a market price of about 80,000 yuan due to the advanced technology and the increase in hardware costs. The market unit price is increased by 20,000 yuan relative to the cost, but the fast grid connection can increase the grid connection time after the new energy station is disconnected from an average of 2 hours to within a few seconds. Calculated based on the capacity of a single new energy station of 100MW, the power generation is 200,000 kWh in 2 hours, and the average on-grid electricity price is 0.45 yuan per kWh, which increases the power generation income by 90,000 yuan; within the 10-year life cycle of the device, 10 grid connections will increase the income by 900,000 yuan, far exceeding the additional purchase cost of 20,000 yuan for the device.

[0134] Table 1 Comparison between the method of the present invention and the traditional manual grid connection method

[0135]

[0136] Optionally, Figure 4 is a schematic diagram of a main connection of a busbar connection new energy station according to an embodiment of the present invention, such as Figure 4As shown, each line has a corresponding line switch, that is, Figure 4 The part represented by numbers, among which 1329, 1101 and 1102 represent circuit breakers. When a single-instantaneous fault occurs on the Yuanba line, the line reclosing success and the timing of the grid-connected process of the new energy station are as follows: 0ms: line fault; 60ms: line protection action trips the 1329 circuit breaker; 100ms: inverter protection action; 1800ms: fault decoupling action trips #1 low 301, #2 low 302, #1SVG353, #2SVG355; 2100ms: line reclosing action closes the 1329 circuit breaker; 3100ms: the grid-connected device issues an order to cut collectors 1 to 11, i.e. 311 to 321; 3140ms: the collectors are detected to be evenly spaced, and an order is issued to close #1 low 301; 4140ms: collector 1 is combined, i.e. 311 switch is closed; 5140ms: collector 2 is combined , i.e. switch 312 is closed; 6140ms: collector line 3, i.e. switch 313 is closed; 7140ms: collector line 4, i.e. switch 314 is closed; 8140ms: collector line 5, i.e. switch 315 is closed; 9140ms: collector line 6, i.e. switch 316 is closed; 10140ms: closing #2 becomes low 302; 11140ms: collector line 7, i.e. switch 317 is closed; 12140ms: collector line 8, i.e. switch 318 is closed; 13140ms: collector line 9, i.e. switch 319 is closed; 14140ms: collector line 10, i.e. switch 320 is closed; 15140ms: collector line 11, i.e. switch 321 is closed; 16140ms: grid connection is completed.

[0137] Optionally, Figure 5 is a schematic diagram of a key grid-connected process according to an embodiment of the present invention, such as Figure 5 As shown, 1. The reclosing is successfully restored and the bus voltage is restored, 2. All collectors are cut off, 3. #1 becomes low, 4. Collectors are closed one by one, 5. #2 becomes low, 6. Collectors are closed one by one.

[0138] In this embodiment, when the grid-connected line instantaneous fault protection reclosing is successful and the high-voltage side bus voltage is restored, the collector line that meets the grid-connected conditions is automatically identified and the electrical connection with the low-voltage side bus is disconnected, and then the low-voltage side of the main transformer and the collector line are reclosed in a certain order to achieve rapid grid connection. This method can replace manual operation after the grid-connected line single instantaneous fault protection reclosing is successful, thereby solving the technical problem of low grid-connected efficiency after the new energy station fault is eliminated, and achieving the technical effect of improving the grid-connected efficiency after the new energy station fault is eliminated.

[0139] According to an embodiment of the present invention, a grid-connected device for a new energy station is also provided. It should be noted that the grid-connected device for a new energy station can be used to execute the grid-connected method for a new energy station in the method embodiment.

[0140] Figure 6 Schematic diagram of a grid-connected device for a new energy station according to an embodiment of the present invention. Figure 6 As shown, the grid-connected device 600 of the new energy station may include: a first determination unit 601 , a second determination unit 602 , a third determination unit 603 and a grid-connected unit 604 .

[0141] The first determining unit 601 is used to determine a fault repair result of the new energy station in response to a fault event occurring in the new energy station, wherein the fault repair result includes a successful fault repair or a failed fault repair.

[0142] The second determining unit 602 is used to determine the grid-connected state of the new energy station in response to the fault repair result being that the fault is repaired successfully, wherein the grid-connected state includes a normal grid-connected state or an abnormal grid-connected state.

[0143] The third determining unit 603 is used to determine the grid connection strategy of the new energy station in response to the grid connection state being the normal grid connection state, wherein the grid connection strategy is used to indicate the rules for connecting the new energy station to the grid.

[0144] The grid connection unit 604 is used to connect the new energy station to the grid according to the grid connection strategy.

[0145] Optionally, the second determination unit 602 may include: a first acquisition module, used to obtain the voltage states of the high-voltage side bus and the low-voltage side bus in the new energy station in response to the fault repair result being successful fault repair, wherein the voltage state includes a voltage state or a no-voltage state; a first determination module, used to determine that the grid-connected state of the new energy station is an abnormal grid-connected state in response to the voltage state of the high-voltage side bus being a no-voltage state, or the voltage state of the low-voltage side bus being a voltage state; a second determination module, used to determine that the grid-connected state of the new energy station is a normal grid-connected state in response to the voltage state of the high-voltage side bus being a voltage state, and the voltage state of the low-voltage side bus being a no-voltage state.

[0146] Optionally, the third determination unit 603 may include: an identification module, used to identify the lines to be connected to the grid in the new energy station in response to the state to be connected to the grid being the normal state to be connected to the grid; a third determination module, used to determine the grid connection strategy of the new energy station based on the lines to be connected to the grid.

[0147] Optionally, the third determination module may include: an acquisition submodule, used to obtain the connection status of the line to be connected to the grid and the low-voltage side bus, wherein the connection status includes a normal connection status and an abnormal connection status; a determination submodule, used to determine the grid connection strategy of the new energy station in response to the connection status being an abnormal connection status; and an ending submodule, used to end the grid connection process of the new energy station in response to the connection status being a normal connection status.

[0148] Optionally, the first determination unit 601 may include: a second acquisition module, used to obtain the fault type of the fault in response to a fault occurring in the new energy station; and a fourth determination module, used to determine the fault repair result of the fault in response to the fault type being a transient fault.

[0149] Optionally, the grid-connected device 600 of the new energy station may include: a termination unit, configured to terminate the grid-connected process of the new energy station in response to the grid-connected state being an abnormal state.

[0150] In this embodiment, in response to a fault event at a new energy station, the fault repair result of the new energy station is determined, wherein the fault repair result includes a successful fault repair or a failed fault repair; in response to the fault repair result being a successful fault repair, the grid-connected state of the new energy station is determined, wherein the grid-connected state includes a normal grid-connected state or an abnormal grid-connected state; in response to the grid-connected state being a normal grid-connected state, the grid-connected strategy of the new energy station is determined, wherein the grid-connected strategy is used to indicate the rules for grid-connecting the new energy station; and the new energy station is grid-connected according to the grid-connected strategy. That is, the present invention determines the grid-connected state of the new energy station after the fault is repaired, determines the grid-connected strategy according to the grid-connected state, and then grid-connects the busbar and the collector on the busbar in the new energy station according to the grid-connected strategy, thereby solving the technical problem of low grid-connected efficiency after the fault of the new energy station is removed, and achieving the technical effect of improving the grid-connected efficiency after the fault of the new energy station is removed.

[0151] According to an embodiment of the present invention, there is further provided a computer-readable storage medium, the storage medium comprising a stored program, wherein the program executes the grid-connected method of the new energy station in the method embodiment.

[0152] According to an embodiment of the present invention, a processor is further provided, the processor being used to run a program, wherein when the program is run, the grid-connection method of the new energy station in the method embodiment is executed.

[0153] According to an embodiment of the present invention, a computer program product is further provided. The computer program product includes computer instructions. When the computer instructions are executed by a processor, the grid-connected method of the new energy station in the method embodiment is implemented.

[0154] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0155] In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0156] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0157] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed over multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0158] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0159] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent functional component, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software functional component, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, disk or optical disk, etc., which can store program codes.

[0160] The above are only preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for connecting a new energy station to the grid, characterized in that: include: In response to a fault event occurring at a new energy station, determining a fault repair result of the new energy station, wherein the fault repair result includes a success in repairing the fault or a failure in repairing the fault; In response to the fault repair result being that the fault is repaired successfully, determining a grid-connected state of the new energy station, wherein the grid-connected state includes a normal grid-connected state or an abnormal grid-connected state; In response to the state to be connected to the grid being the normal state to be connected to the grid, determining a grid connection strategy for the new energy station, wherein the grid connection strategy is used to indicate a rule for connecting the new energy station to the grid; According to the grid-connected strategy, the new energy station is connected to the grid.

2. The method according to claim 1, characterized in that In response to the fault repair result being that the fault is repaired successfully, determining the grid-connection state of the new energy station includes: In response to the fault repair result being that the fault is repaired successfully, respectively obtaining voltage states of the high-voltage side bus and the low-voltage side bus in the new energy station, wherein the voltage state includes a voltage state or a no-voltage state; In response to the voltage state of the high-voltage side bus being the no-voltage state, or the voltage state of the low-voltage side bus being the voltage state, determining that the grid-connected state of the new energy station is the abnormal grid-connected state; In response to the voltage state of the high-voltage side bus being the voltage state and the voltage state of the low-voltage side bus being the no-voltage state, it is determined that the grid-connected state of the new energy station is the normal grid-connected state.

3. The method according to claim 1, characterized in that In response to the state to be connected to the grid being the normal state to be connected to the grid, determining a grid connection strategy for the new energy station includes: In response to the state to be connected to the grid being the normal state to be connected to the grid, identifying a line to be connected to the grid in the new energy station; Based on the line to be connected to the grid, the grid connection strategy of the new energy station is determined.

4. The method according to claim 3, characterized in that Determining the grid connection strategy of the new energy station based on the line to be connected to the grid includes: Acquire the connection status between the line to be connected to the grid and the low-voltage side bus, wherein the connection status includes a normal connection status and an abnormal connection status; In response to the connection state being the abnormal connection state, determining the grid connection strategy of the new energy station; In response to the connection state being the normal connection state, the grid connection process of the new energy station is ended.

5. The method according to claim 1, characterized in that In response to a new energy station having a fault, determining a fault repair result of the new energy station includes: In response to the fault occurring in the new energy station, obtaining a fault type of the fault; In response to the fault type being a transient fault, the fault repair result of the fault is determined.

6. The method according to claim 3, characterized in that The method further comprises: In response to the state to be connected to the grid being the abnormal state, the grid connection process of the new energy station is terminated.

7. A grid-connected device for a new energy station, characterized in that: include: A first determining unit, configured to determine a fault repair result of the new energy station in response to a fault event occurring at the new energy station, wherein the fault repair result includes a success in repairing the fault or a failure in repairing the fault; A second determining unit is configured to determine, in response to the fault repair result being that the fault is repaired successfully, a grid-connected state of the new energy station, wherein the grid-connected state includes a normal grid-connected state or an abnormal grid-connected state; A third determining unit is configured to determine a grid connection strategy for the new energy station in response to the state to be connected to the grid being the normal state to be connected to the grid, wherein the grid connection strategy is used to indicate a rule for connecting the new energy station to the grid; A grid-connected unit is used to connect the new energy station to the grid according to the grid-connected strategy.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored program, wherein when the program is executed by a processor, the device where the storage medium is located is controlled to execute the method according to any one of claims 1 to 6.

9. A processor, characterized in that: The processor is used to run a program, wherein the program executes the method according to any one of claims 1 to 6 when running.

10. A computer program product, characterized in that The computer program product comprises computer instructions, which implement the method according to any one of claims 1 to 6 when executed by a processor.

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