Secondary grid connection device and method for medium-voltage generator car

Abstract

The invention discloses a secondary grid connection device and method for a medium-voltage generator car. The device comprises the medium-voltage generator car, a grid connection control device and a load. The grid-connected control device is used for collecting power grid information of power equipment to be connected in a grid in real time and transmitting the power grid information to the medium-voltage power generation vehicle; the medium-voltage generator car is used for adjusting own power parameters according to the power grid information until the adjusted own power parameters of the medium-voltage generator car meet secondary grid-connected conditions, and sending a switching-on confirmation signal to the grid-connected control device, so that the grid-connected control device sends a switching-on confirmation signal to the grid-connected control device after receiving the switching-on confirmation signal, and the medium-voltage generator car sends the switching-on confirmation signal to the grid-connected control device after receiving the switching-on confirmation signal. Sending a closing operation signal to the to-be-connected power equipment; and the to-be-grid-connected power equipment is used for executing a switching-on operation according to the switching-on operation signal so as to realize secondary grid connection of the medium-voltage generator car and the to-be-grid-connected power equipment. According to the invention, the secondary grid connection process can be simplified, and the secondary grid connection efficiency of the medium-voltage generator car can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of grid-connected power generation vehicles, and in particular to a secondary grid-connected device and method for a medium-voltage power generation vehicle. Background Art

[0002] As society's demands for power supply reliability and continuity continue to increase, medium-voltage generator trucks are widely used in scenarios such as natural disaster relief and large-scale event support. While the existing primary grid-connection technology (inductive connection) for medium-voltage generator trucks has been refined, the existing secondary grid-connection technology (inductive disconnection) requires connecting cables to the power source to be connected to collect data and establish a temporary bypass. This method requires power maintenance personnel to complete cable laying (laying out and fixing), secondary wiring (wire stripping, terminal crimping, insulation treatment, etc.), and temporary bypass construction (wire jumpering, switch installation, etc.). The operation steps are cumbersome and highly dependent on the construction of power maintenance personnel. Furthermore, it cannot automatically collect grid information from the power equipment to be connected to the grid, and manual intervention is required during grid information collection, resulting in low secondary grid connection efficiency. Summary of the Invention

[0003] The embodiments of the present invention provide a medium-voltage generator vehicle secondary grid-connected device and method, which can simplify the secondary grid-connected process and improve the efficiency of the medium-voltage generator vehicle secondary grid-connected.

[0004] An embodiment of the present invention provides a medium-voltage generator vehicle secondary grid-connected device, comprising: a medium-voltage generator vehicle, a grid-connected control device, and a load;

[0005] The first end of the medium voltage generator vehicle is connected to the load, the second end of the medium voltage generator vehicle is connected to the first end of the grid connection control device, and the second end of the grid connection control device is connected to the power equipment to be connected to the grid;

[0006] The grid connection control device is used to collect grid information of the power equipment to be connected to the grid in real time and transmit the grid information to the medium voltage generator vehicle; wherein the grid information includes grid frequency, grid voltage amplitude and grid phase;

[0007] The medium-voltage generator car is configured to adjust its own power parameters according to the grid information until the adjusted power parameters of the medium-voltage generator car meet the secondary grid-connection conditions, and then send a closing confirmation signal to the grid-connection control device, so that the grid-connection control device sends a closing operation signal to the power equipment to be connected to the grid after receiving the closing confirmation signal; wherein the power parameters include the generator car frequency, the generator car voltage amplitude, and the generator car phase; the secondary grid-connection conditions include: the absolute value of the frequency deviation between the generator car frequency and the grid frequency is not greater than the frequency deviation threshold, the absolute value of the voltage deviation between the generator car voltage amplitude and the grid voltage amplitude is not greater than the voltage deviation threshold, and the generator car phase is consistent with the grid phase;

[0008] The power equipment to be connected to the grid is used to perform a closing operation according to a closing operation signal to achieve secondary grid connection between the medium-voltage power generation vehicle and the power equipment to be connected to the grid.

[0009] Furthermore, the power equipment to be connected to the grid includes overhead lines to be connected to the grid and switch cabinets to be connected to the grid;

[0010] The performing of the closing operation according to the closing operation signal to achieve secondary grid connection between the medium voltage generator vehicle and the power equipment to be grid-connected includes:

[0011] When the power equipment to be connected to the grid is an overhead line to be connected to the grid, the overhead line to be connected to the grid controls the distribution network switch of the overhead line to be connected to the grid to close according to the closing operation signal, thereby realizing the secondary grid connection between the medium-voltage power generation vehicle and the overhead line to be connected to the grid; wherein the distribution network switch includes a tie switch and a section switch;

[0012] When the power equipment to be connected to the grid is a switch cabinet to be connected to the grid, the switch cabinet to be connected to the grid controls the closing of the medium-voltage switchgear of the switch cabinet to be connected to the grid according to the closing operation signal, thereby realizing the secondary grid connection of the medium-voltage power generation vehicle and the switch cabinet to be connected to the grid; wherein, the medium-voltage switchgear includes: a medium-voltage circuit breaker and a load switch.

[0013] Furthermore, the second end of the grid connection control device is connected to the power equipment to be connected to the grid, including:

[0014] When the power equipment to be connected to the grid is a switch cabinet to be connected to the grid, the second end of the grid connection control device is connected to the secondary opening and closing circuit of the switch cabinet to be connected to the grid via a 485 communication line, and the second end of the grid connection control device is connected to the live display test hole of the switch cabinet to be connected to the grid via a 485 communication line;

[0015] When the power equipment to be connected to the grid is an overhead line to be connected to the grid, the second end of the grid connection control device is connected to the line of the overhead line to be connected to the grid through a 485 communication line, and the second end of the grid connection control device is connected to the opening and closing circuit of the feeder terminal unit of the overhead line to be connected to the grid through the 485 communication line.

[0016] Furthermore, the second end of the grid connection control device is connected to the power equipment to be connected to the grid, including:

[0017] When the power equipment to be connected to the grid is a switch cabinet to be connected to the grid, the second end of the grid connection control device establishes a wireless communication connection with the secondary opening and closing circuit of the switch cabinet to be connected to the grid, and the second end of the grid connection control device establishes a wireless communication connection with the live display test hole of the switch cabinet to be connected to the grid;

[0018] When the power equipment to be connected to the grid is an overhead line to be connected to the grid, the second end of the grid connection control device establishes a wireless communication connection with the line of the overhead line to be connected to the grid, and the second end of the grid connection control device establishes a wireless communication connection with the feeder terminal unit of the overhead line to be connected to the grid.

[0019] Furthermore, the medium voltage generator vehicle is also used for:

[0020] After the medium-voltage generator car and the power equipment to be connected to the grid are connected to the grid for the second time, the output power of the medium-voltage generator car is gradually reduced so that the load is powered by the power equipment to be connected to the grid instead of the medium-voltage generator car.

[0021] Furthermore, the second end of the medium voltage generator vehicle is connected to the first end of the grid connection control device, including:

[0022] The second end of the medium voltage generator vehicle is connected to the first end of the grid connection control device via a CAN to optical fiber communication line.

[0023] Furthermore, the frequency deviation threshold value is between 0 and 0.5 Hz.

[0024] Furthermore, the voltage deviation threshold value is between 0 and 10% of the grid voltage amplitude.

[0025] Based on the above-mentioned device embodiment, the present invention provides a corresponding method embodiment;

[0026] An embodiment of the present invention provides a secondary grid-connected method for a medium-voltage generator vehicle, which is applied to a grid-connected control device for a secondary grid-connected device of a medium-voltage generator vehicle;

[0027] The secondary grid-connected method for a medium-voltage generator vehicle comprises:

[0028] Real-time collection of grid information of the power equipment to be connected to the grid, and transmission of the grid information to the medium-voltage generator car, so that the medium-voltage generator car adjusts its own power parameters according to the grid information, until the adjusted power parameters of the medium-voltage generator car meet the secondary grid connection conditions, and then sends a closing confirmation signal to the grid connection control device; wherein, the grid information includes the grid frequency, the grid voltage amplitude and the grid phase; the power parameters include the generator car frequency, the generator car voltage amplitude and the generator car phase; the secondary grid connection conditions include: the absolute value of the frequency deviation between the generator car frequency and the grid frequency is not greater than the frequency deviation threshold, the absolute value of the voltage deviation between the generator car voltage amplitude and the grid voltage amplitude is not greater than the voltage deviation threshold, and the generator car phase is consistent with the grid phase;

[0029] After receiving the closing confirmation signal, a closing operation signal is sent to the power equipment to be connected to the grid, so that the power equipment to be connected to the grid performs a closing operation according to the closing operation signal, thereby realizing secondary grid connection between the medium voltage power generation vehicle and the power equipment to be connected to the grid.

[0030] Furthermore, the power equipment to be connected to the grid includes overhead lines to be connected to the grid and switch cabinets to be connected to the grid;

[0031] The performing of the closing operation according to the closing operation signal to achieve secondary grid connection between the medium voltage generator vehicle and the power equipment to be grid-connected includes:

[0032] When the power equipment to be connected to the grid is an overhead line to be connected to the grid, the overhead line to be connected to the grid controls the distribution network switch of the overhead line to be connected to the grid to close according to the closing operation signal, thereby realizing the secondary grid connection between the medium-voltage power generation vehicle and the overhead line to be connected to the grid; wherein the distribution network switch includes a tie switch and a section switch;

[0033] When the power equipment to be connected to the grid is a switch cabinet to be connected to the grid, the switch cabinet to be connected to the grid controls the closing of the medium-voltage switchgear of the switch cabinet to be connected to the grid according to the closing operation signal, thereby realizing the secondary grid connection of the medium-voltage power generation vehicle and the switch cabinet to be connected to the grid; wherein, the medium-voltage switchgear includes: a medium-voltage circuit breaker and a load switch.

[0034] The following beneficial effects are achieved by implementing the present invention:

[0035] The present invention provides a secondary grid-connected device and method for a medium-voltage generator vehicle. The device includes a medium-voltage generator vehicle, a grid-connected control device, and a load. Before secondary grid connection, the first end of the medium-voltage generator vehicle is connected to the load, the second end of the medium-voltage generator vehicle is connected to the first end of the grid-connected control device, and the second end of the grid-connected control device is connected to the power equipment to be grid-connected. During secondary grid connection, the grid-connected control device collects grid information of the power equipment to be grid-connected in real time and transmits it to the medium-voltage generator vehicle. The medium-voltage generator vehicle adjusts its own power parameters based on the grid information until the adjusted power parameters of the medium-voltage generator vehicle meet the secondary grid connection conditions. The grid-connected control device then controls the power equipment to be grid-connected to perform a closing operation, thereby achieving secondary grid connection between the medium-voltage generator vehicle and the power equipment to be grid-connected. By adding a grid-connected control device between the medium-voltage generator vehicle and the power equipment to be connected to the grid, the connection part between the medium-voltage generator vehicle and the grid-connected control device can be reused. During the secondary grid connection, it is only necessary to establish a connection between the grid-connected control device and the power equipment to be connected to the grid, reducing the construction dependence on power maintenance personnel; in addition, the addition of the grid-connected control device allows the power information of the power equipment to be connected to the grid to be automatically and centrally collected through the grid control device, improving the efficiency of grid information collection and further improving the efficiency of secondary grid connection. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1The present invention provides a schematic structural diagram of a secondary grid-connected device for a medium-voltage power generation vehicle according to an embodiment of the present invention.

[0037] Figure 2 It is a schematic diagram of the secondary grid connection of a switch cabinet provided by an embodiment of the present invention.

[0038] Figure 3 It is a schematic diagram of secondary grid connection of overhead lines provided by one embodiment of the present invention.

[0039] Figure 4 The present invention provides a flow chart of a secondary grid-connected method for a medium-voltage generator vehicle according to an embodiment of the present invention. DETAILED DESCRIPTION

[0040] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0041] To make the objectives, technical solutions, and advantages of this application more clear, the technical solutions in this application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0043] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0044] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0045] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0046] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0047] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0048] like Figure 1 As shown, a medium voltage generator vehicle secondary grid-connected device provided by one embodiment of the present invention comprises: a medium voltage generator vehicle, a grid-connected control device and a load;

[0049] The first end (output interface) of the medium-voltage power generation vehicle is connected to the load, the second end (communication interface) of the medium-voltage power generation vehicle is connected to the first end (synchronization communication interface) of the grid connection control device, and the second end (sampling control interface) of the grid connection control device is connected to the power equipment to be connected to the grid;

[0050] The grid connection control device is used to collect grid information of the power equipment to be connected to the grid in real time and transmit the grid information to the medium voltage generator vehicle; wherein the grid information includes grid frequency, grid voltage amplitude and grid phase;

[0051] The medium-voltage generator car is configured to adjust its own power parameters according to the grid information until the adjusted power parameters of the medium-voltage generator car meet the secondary grid-connection conditions, and then send a closing confirmation signal to the grid-connection control device, so that the grid-connection control device sends a closing operation signal to the power equipment to be connected to the grid after receiving the closing confirmation signal; wherein the power parameters include the generator car frequency, the generator car voltage amplitude, and the generator car phase; the secondary grid-connection conditions include: the absolute value of the frequency deviation between the generator car frequency and the grid frequency is not greater than the frequency deviation threshold, the absolute value of the voltage deviation between the generator car voltage amplitude and the grid voltage amplitude is not greater than the voltage deviation threshold, and the generator car phase is consistent with the grid phase;

[0052] The power equipment to be connected to the grid is used to perform a closing operation according to a closing operation signal to achieve secondary grid connection between the medium-voltage power generation vehicle and the power equipment to be connected to the grid.

[0053] Specifically, in the present invention, a medium-voltage generator vehicle primarily refers to a 10kV generator vehicle. The first end of the medium-voltage generator vehicle is connected to the load via a cable. The connection to the load can be anywhere, regardless of the load connection location. The second end of the medium-voltage generator vehicle is connected to the grid connection control device.

[0054] In a preferred embodiment, the second end of the medium voltage generator vehicle is connected to the first end of the grid connection control device, including: the second end of the medium voltage generator vehicle is connected to the first end of the grid connection control device via a CAN to fiber optic communication line.

[0055] Specifically, in the present invention, the second end of the medium-voltage generator vehicle is connected to the first end of the grid-connected control device via a CAN-to-fiber optic communication line, without using cables for connection. On the one hand, this can reduce the cost of laying cables. On the other hand, the CAN-to-fiber optic communication line connection method can break through the transmission distance limitations of the traditional CAN bus and support flexible deployment. Medium-voltage generator vehicles are usually deployed in outdoor temporary power supply scenarios, and the distance between them and the grid-connected control device may be as long as several kilometers. If the traditional CAN bus is used, the transmission signal will be weakened during long-distance transmission. The use of a CAN-to-fiber optic communication line can solve the problem of weak signal transmission over long distances and ensure the stability of signal and data transmission between the medium-voltage generator vehicle and the grid-connected control device.

[0056] The second end of the grid-connected control device is connected to the power equipment to be connected to the grid. As a medium connecting the medium-voltage generator vehicle and the power equipment to be connected to the grid, the grid-connected control device plays a role in reducing the length of cable laying and protecting the medium-voltage generator vehicle.

[0057] The main function of the grid connection control device is to collect real-time grid information from the power equipment to be connected to the grid, including grid frequency, grid voltage amplitude, and grid phase, and transmit this collected grid information to the medium-voltage generator vehicle via message or signal encapsulation. Preferably, the grid information can be collected by a power supply information collection device deployed on the power equipment to be connected to the grid.

[0058] After receiving the grid information collected by the grid control device, the medium-voltage generator car uses it as an adjustment target and adjusts its own power parameters so that the medium-voltage generator car's own power parameters can meet the secondary grid connection conditions after adjustment. Among them, the secondary grid connection conditions require that the following three requirements be met at the same time: (1) the absolute value of the frequency deviation between the generator car frequency and the grid frequency is not greater than the frequency deviation threshold; (2) the absolute value of the voltage deviation between the generator car voltage amplitude and the grid voltage amplitude is not greater than the voltage deviation threshold; (3) the generator car phase is consistent with the grid phase.

[0059] In a preferred embodiment, the frequency deviation threshold value is between 0 and 0.5 Hz.

[0060] In a preferred embodiment, the voltage deviation threshold value is between 0 and 10% of the grid voltage amplitude.

[0061] Specifically, the value range of the frequency deviation threshold is (0, 0.5), and the value range of the voltage deviation threshold is (0, 10% of the grid voltage amplitude). The smaller the values ​​of the frequency deviation threshold and the voltage deviation threshold, the better. In the present invention, the frequency deviation threshold is selected as 0.1 Hz, and the voltage deviation threshold is selected as 5% of the grid voltage amplitude.

[0062] The medium-voltage generator vehicle analyzes the acquired grid information to obtain the grid frequency, grid voltage amplitude, and grid phase. It also obtains its own generator vehicle frequency, voltage amplitude, and phase. By comparing the generator vehicle frequency with the grid frequency, it determines the frequency deviation between the two frequencies. Based on this frequency deviation, the generator vehicle frequency is adjusted so that the absolute value of the difference between the adjusted generator vehicle frequency and the grid frequency is no greater than 0.1 Hz. Similarly, by comparing the generator vehicle voltage amplitude with the grid voltage amplitude, it determines the voltage deviation between the generator vehicle voltage amplitude and the grid voltage amplitude. Based on this voltage deviation, the generator vehicle voltage amplitude is adjusted so that the absolute value of the difference between the adjusted generator vehicle voltage amplitude and the grid voltage amplitude is no greater than 5% of the grid voltage amplitude. By calculating the phase difference between the generator vehicle phase and the grid phase, the generator vehicle phase is adjusted based on this phase difference so that the adjusted generator vehicle phase is consistent with the grid phase, or the phase difference between the generator vehicle phase and the grid phase is close to 0°.

[0063] When the medium-voltage generator vehicle adjusts its own power parameters to meet the secondary grid connection conditions, it sends a closing confirmation signal to the grid connection control device, informing it that it can control the power equipment to be connected to the grid to perform the closing operation and achieve grid connection. After receiving the closing confirmation signal, the grid connection control device sends a closing operation signal to the power equipment to be connected to the grid, informing it that it can close the circuit breaker and achieve grid connection.

[0064] In a preferred embodiment, the power equipment to be connected to the grid includes an overhead line to be connected to the grid and a switch cabinet to be connected to the grid;

[0065] The performing of the closing operation according to the closing operation signal to realize the secondary grid connection between the medium-voltage power generation vehicle and the power equipment to be connected to the grid includes: when the power equipment to be connected to the grid is an overhead line to be connected to the grid, the overhead line to be connected to the grid controls the distribution network switch of the overhead line to be connected to the grid to close according to the closing operation signal, thereby realizing the secondary grid connection between the medium-voltage power generation vehicle and the overhead line to be connected to the grid; wherein, the distribution network switch includes a connecting switch and a section switch; when the power equipment to be connected to the grid is a switch cabinet to be connected to the grid, the switch cabinet to be connected to the grid controls the medium-voltage switchgear of the switch cabinet to be connected to the grid to close according to the closing operation signal, thereby realizing the secondary grid connection between the medium-voltage power generation vehicle and the switch cabinet to be connected to the grid; wherein, the medium-voltage switchgear includes: a medium-voltage circuit breaker and a load switch.

[0066] Specifically, in the present invention, the power equipment to be connected to the grid mainly includes overhead lines to be connected to the grid and switch cabinets to be connected to the grid. Preferably, in addition to the overhead lines and switch cabinets provided by the present invention, the power equipment to be connected to the grid can be adjusted based on the equipment to be connected to the grid. When adjusting, it is only necessary to adjust the communication method between the grid control device and the power equipment to be connected to the grid, and they will not be listed one by one here.

[0067] When the grid-connected switchgear is used as the grid-connected power equipment, the connection structure diagram between it and the grid-connected control device is as follows: Figure 2 As shown in the figure, when the overhead line to be connected to the grid is used as the power equipment to be connected to the grid, the connection structure diagram between it and the grid control device is as follows: Figure 3 As shown. Among them, Figure 2 and Figure 3 The emergency power supply vehicle mentioned above is the medium voltage generator vehicle.

[0068] When the power equipment to be connected to the grid is a switchgear to be connected to the grid, if the switchgear to be connected to the grid receives a closing operation signal, the main device that receives the closing operation signal is the secondary opening and closing controller on the switchgear to be connected to the grid. After receiving the closing operation signal, the secondary opening controller automatically closes the medium-voltage switchgear, such as closing the medium-voltage circuit breaker or closing the load switch, to complete the closing operation of the switchgear to be connected to the grid.

[0069] When the power equipment to be connected to the grid is an overhead line to be connected to the grid, if the overhead line to be connected to the grid receives a closing operation signal, the main receiver of the closing operation signal is the feeder terminal unit in the overhead line to be connected to the grid. After receiving the closing operation signal, the feeder terminal unit automatically closes the distribution network switch, such as closing the connecting switch or closing the section switch.

[0070] In a preferred embodiment, the second end of the grid-connected control device is connected to the power equipment to be connected to the grid, including: when the power equipment to be connected to the grid is a switch cabinet to be connected to the grid, the second end of the grid-connected control device is connected to the secondary opening and closing circuit of the switch cabinet to be connected to the grid through a 485 communication line, and the second end of the grid-connected control device is connected to the live display test hole of the switch cabinet to be connected to the grid through a 485 communication line; when the power equipment to be connected to the grid is an overhead line to be connected to the grid, the second end of the grid-connected control device is connected to the line of the overhead line to be connected to the grid through a 485 communication line, and the second end of the grid-connected control device is connected to the opening and closing circuit of the feeder terminal unit of the overhead line to be connected to the grid through the 485 communication line.

[0071] Specifically, such as Figure 2 As shown, when the power equipment to be connected to the grid is a switchgear to be connected to the grid, the grid control device is connected to the secondary opening and closing circuit of the switchgear to be connected to the grid via a 485 communication line. This connection enables control of the secondary opening and closing controller. The grid control device is connected to the live display test hole of the switchgear to be connected to the grid via a 485 communication line. When the power equipment to be connected to the grid is an overhead line to be connected to the grid, the grid control device is connected to the line body of the overhead line to be connected to the grid via a 485 communication line. The grid control device is connected to the opening and closing circuit of the feeder terminal unit (FTU) of the overhead line to be connected to the grid via the 485 communication line. This connection enables control of the feeder terminal unit (FTU). The use of 485 communication lines has the advantage of low cost. Compared with laying cables, it can greatly reduce the construction cost between the medium-voltage generator vehicle and the power equipment to be connected to the grid.

[0072] In another parallel embodiment, the second end of the grid-connected control device is connected to the power equipment to be connected to the grid, including: when the power equipment to be connected to the grid is a switch cabinet to be connected to the grid, the second end of the grid-connected control device establishes a wireless communication connection with the secondary opening and closing circuit of the switch cabinet to be connected to the grid, and the second end of the grid-connected control device establishes a wireless communication connection with the live display test hole of the switch cabinet to be connected to the grid; when the power equipment to be connected to the grid is an overhead line to be connected to the grid, the second end of the grid-connected control device establishes a wireless communication connection with the line of the overhead line to be connected to the grid, and the second end of the grid-connected control device establishes a wireless communication connection with the feeder terminal unit of the overhead line to be connected to the grid.

[0073] Specifically, in addition to the aforementioned connection via 485 communication lines, wireless transmission, such as 4G and 5G wireless communications, can also be used between the grid-connected control device and the power equipment to be connected to the grid to transmit grid information and control signals. Wireless transmission offers greater flexibility than 485 communication line routing, but is limited by transmission distance. Therefore, the optimal communication method can be selected based on the distance between the grid-connected control device and the power equipment to be connected to the grid.

[0074] In a preferred embodiment, the medium-voltage generator vehicle is also used to: after the medium-voltage generator vehicle and the power equipment to be connected to the grid are connected for the second time, reduce the output power of the medium-voltage generator vehicle so that the load is switched from being powered by the medium-voltage generator vehicle to being powered by the power equipment to be connected to the grid.

[0075] Specifically, after the secondary grid connection is completed, the medium-voltage generator car needs to gradually reduce its output power so that the load connected to the medium-voltage generator car is smoothly switched from being jointly powered by the medium-voltage generator car and the power grid (i.e., the power grid connected to the power equipment to be connected to the grid) to being powered only by the power grid. When the output power of the medium-voltage generator car decreases to 0, the load is only powered by the power grid, and the medium-voltage generator car is shut down, realizing the transition of load power supply from power supply by the medium-voltage generator car to power supply by the power grid.

[0076] Based on the above-mentioned device embodiment, the present invention provides a corresponding method embodiment.

[0077] like Figure 4 As shown, an embodiment of the present invention provides a medium voltage generator vehicle secondary grid connection method, which is applied to the grid connection control device of the above medium voltage generator vehicle secondary grid connection device;

[0078] The secondary grid-connected method for a medium-voltage generator vehicle comprises:

[0079] Step S1: collecting grid information of the power equipment to be connected to the grid in real time, and transmitting the grid information to the medium-voltage generator car, so that the medium-voltage generator car adjusts its own power parameters according to the grid information, until the adjusted power parameters of the medium-voltage generator car meet the secondary grid connection conditions, and then sends a closing confirmation signal to the grid connection control device; wherein, the grid information includes grid frequency, grid voltage amplitude and grid phase; the power parameters include generator car frequency, generator car voltage amplitude and generator car phase; the secondary grid connection conditions include: the absolute value of the frequency deviation between the generator car frequency and the grid frequency is not greater than the frequency deviation threshold, the absolute value of the voltage deviation between the generator car voltage amplitude and the grid voltage amplitude is not greater than the voltage deviation threshold, and the generator car phase is consistent with the grid phase;

[0080] Step S2: After receiving the closing confirmation signal, a closing operation signal is sent to the power equipment to be connected to the grid, so that the power equipment to be connected to the grid performs a closing operation according to the closing operation signal, thereby realizing secondary grid connection between the medium voltage generator vehicle and the power equipment to be connected to the grid.

[0081] In a preferred embodiment, the power equipment to be connected to the grid includes an overhead line to be connected to the grid and a switch cabinet to be connected to the grid;

[0082] The performing of the closing operation according to the closing operation signal to achieve secondary grid connection between the medium voltage generator vehicle and the power equipment to be grid-connected includes:

[0083] When the power equipment to be connected to the grid is an overhead line to be connected to the grid, the overhead line to be connected to the grid controls the distribution network switch of the overhead line to be connected to the grid to close according to the closing operation signal, thereby realizing the secondary grid connection between the medium-voltage power generation vehicle and the overhead line to be connected to the grid; wherein the distribution network switch includes a tie switch and a section switch;

[0084] When the power equipment to be connected to the grid is a switch cabinet to be connected to the grid, the switch cabinet to be connected to the grid controls the closing of the medium-voltage switchgear of the switch cabinet to be connected to the grid according to the closing operation signal, thereby realizing the secondary grid connection of the medium-voltage power generation vehicle and the switch cabinet to be connected to the grid; wherein, the medium-voltage switchgear includes: a medium-voltage circuit breaker and a load switch.

[0085] The following beneficial effects are achieved by implementing the present invention:

[0086] 1. Reduce cable laying and lower the investment cost and implementation difficulty of secondary grid connection.

[0087] 2. Reduce the restrictions on secondary grid connection caused by the distance between the medium-voltage generator vehicle and the power equipment to be connected to the grid, and improve the convenience of secondary grid connection.

[0088] 3. The grid information of the power equipment to be connected to the grid is automatically and centrally collected through the grid connection control device, which can simplify the secondary grid connection process, reduce manual dependence, and improve the efficiency of the secondary grid connection of the medium-voltage generator vehicle.

[0089] It should be noted that the device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed across multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the present embodiment. In addition, in the drawings of the device embodiments provided by the present invention, the connection relationship between the modules indicates that there is a communication connection between them, which may be specifically implemented as one or more communication buses or signal lines. A person of ordinary skill in the art can understand and implement the present invention without inventive effort.

[0090] Those skilled in the art will clearly understand that for the sake of convenience and brevity, the specific working process of the device described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0091] The above is a preferred embodiment 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 are also considered to be within the scope of protection of the present invention.

Claims

1. A medium voltage generator secondary grid-connected device, characterized in that: include: Medium voltage generator vehicles, grid connection control devices and loads; The first end of the medium voltage generator vehicle is connected to the load, the second end of the medium voltage generator vehicle is connected to the first end of the grid connection control device, and the second end of the grid connection control device is connected to the power equipment to be connected to the grid; The grid connection control device is used to collect grid information of the power equipment to be connected to the grid in real time and transmit the grid information to the medium voltage generator vehicle; wherein the grid information includes grid frequency, grid voltage amplitude and grid phase; The medium-voltage generator car is configured to adjust its own power parameters according to the grid information until the adjusted power parameters of the medium-voltage generator car meet the secondary grid-connection conditions, and then send a closing confirmation signal to the grid-connection control device, so that the grid-connection control device sends a closing operation signal to the power equipment to be connected to the grid after receiving the closing confirmation signal; wherein the power parameters include the generator car frequency, the generator car voltage amplitude, and the generator car phase; the secondary grid-connection conditions include: the absolute value of the frequency deviation between the generator car frequency and the grid frequency is not greater than the frequency deviation threshold, the absolute value of the voltage deviation between the generator car voltage amplitude and the grid voltage amplitude is not greater than the voltage deviation threshold, and the generator car phase is consistent with the grid phase; The power equipment to be connected to the grid is used to perform a closing operation according to a closing operation signal to achieve secondary grid connection between the medium-voltage power generation vehicle and the power equipment to be connected to the grid.

2. A medium voltage generator vehicle secondary grid connection device according to claim 1, characterized in that: The power equipment to be connected to the grid includes overhead lines to be connected to the grid and switch cabinets to be connected to the grid; The performing of the closing operation according to the closing operation signal to achieve secondary grid connection between the medium voltage generator vehicle and the power equipment to be grid-connected includes: When the power equipment to be connected to the grid is an overhead line to be connected to the grid, the overhead line to be connected to the grid controls the distribution network switch of the overhead line to be connected to the grid to close according to the closing operation signal, thereby realizing the secondary grid connection between the medium-voltage power generation vehicle and the overhead line to be connected to the grid; wherein the distribution network switch includes a tie switch and a section switch; When the power equipment to be connected to the grid is a switch cabinet to be connected to the grid, the switch cabinet to be connected to the grid controls the closing of the medium-voltage switchgear of the switch cabinet to be connected to the grid according to the closing operation signal, thereby realizing the secondary grid connection of the medium-voltage power generation vehicle and the switch cabinet to be connected to the grid; wherein, the medium-voltage switchgear includes: a medium-voltage circuit breaker and a load switch.

3. A medium voltage generator vehicle secondary grid connection device according to claim 2, characterized in that: The second end of the grid connection control device is connected to the power equipment to be connected to the grid, including: When the power equipment to be connected to the grid is a switch cabinet to be connected to the grid, the second end of the grid connection control device is connected to the secondary opening and closing circuit of the switch cabinet to be connected to the grid via a 485 communication line, and the second end of the grid connection control device is connected to the live display test hole of the switch cabinet to be connected to the grid via a 485 communication line; When the power equipment to be connected to the grid is an overhead line to be connected to the grid, the second end of the grid connection control device is connected to the line of the overhead line to be connected to the grid through a 485 communication line, and the second end of the grid connection control device is connected to the opening and closing circuit of the feeder terminal unit of the overhead line to be connected to the grid through the 485 communication line.

4. A medium voltage generator vehicle secondary grid connection device according to claim 2, characterized in that: The second end of the grid connection control device is connected to the power equipment to be connected to the grid, including: When the power equipment to be connected to the grid is a switch cabinet to be connected to the grid, the second end of the grid connection control device establishes a wireless communication connection with the secondary opening and closing circuit of the switch cabinet to be connected to the grid, and the second end of the grid connection control device establishes a wireless communication connection with the live display test hole of the switch cabinet to be connected to the grid; When the power equipment to be connected to the grid is an overhead line to be connected to the grid, the second end of the grid connection control device establishes a wireless communication connection with the line of the overhead line to be connected to the grid, and the second end of the grid connection control device establishes a wireless communication connection with the feeder terminal unit of the overhead line to be connected to the grid.

5. A medium voltage generator vehicle secondary grid connection device according to claim 1, characterized in that: The medium voltage generator vehicle is also used for: After the medium-voltage generator car and the power equipment to be connected to the grid are connected to the grid for the second time, the output power of the medium-voltage generator car is gradually reduced so that the load is powered by the power equipment to be connected to the grid instead of the medium-voltage generator car.

6. A medium voltage generator vehicle secondary grid connection device according to claim 1, characterized in that: The second end of the medium voltage generator vehicle is connected to the first end of the grid connection control device, including: The second end of the medium voltage generator vehicle is connected to the first end of the grid connection control device via a CAN to optical fiber communication line.

7. A medium voltage generator vehicle secondary grid connection device according to claim 1, characterized in that: The frequency deviation threshold value is between 0 and 0.5 Hz.

8. The medium voltage generator vehicle secondary grid connection device according to claim 1, characterized in that: The voltage deviation threshold value is between 0 and 10% of the grid voltage amplitude.

9. A method for secondary grid connection of a medium voltage generator vehicle, characterized in that: A grid-connected control device for a secondary grid-connected device for a medium-voltage generator vehicle as claimed in any one of claims 1 to 8; The secondary grid-connected method for a medium-voltage generator vehicle comprises: Real-time collection of grid information of the power equipment to be connected to the grid, and transmission of the grid information to the medium-voltage generator car, so that the medium-voltage generator car adjusts its own power parameters according to the grid information, until the adjusted power parameters of the medium-voltage generator car meet the secondary grid connection conditions, and then sends a closing confirmation signal to the grid connection control device; wherein, the grid information includes the grid frequency, the grid voltage amplitude and the grid phase; the power parameters include the generator car frequency, the generator car voltage amplitude and the generator car phase; the secondary grid connection conditions include: the absolute value of the frequency deviation between the generator car frequency and the grid frequency is not greater than the frequency deviation threshold, the absolute value of the voltage deviation between the generator car voltage amplitude and the grid voltage amplitude is not greater than the voltage deviation threshold, and the generator car phase is consistent with the grid phase; After receiving the closing confirmation signal, a closing operation signal is sent to the power equipment to be connected to the grid, so that the power equipment to be connected to the grid performs a closing operation according to the closing operation signal, thereby realizing secondary grid connection between the medium voltage power generation vehicle and the power equipment to be connected to the grid.

10. A method for secondary grid connection of a medium voltage generator vehicle according to claim 9, characterized in that: The power equipment to be connected to the grid includes overhead lines to be connected to the grid and switch cabinets to be connected to the grid; The performing of the closing operation according to the closing operation signal to achieve secondary grid connection between the medium voltage generator vehicle and the power equipment to be grid-connected includes: When the power equipment to be connected to the grid is an overhead line to be connected to the grid, the overhead line to be connected to the grid controls the distribution network switch of the overhead line to be connected to the grid to close according to the closing operation signal, thereby realizing the secondary grid connection between the medium-voltage power generation vehicle and the overhead line to be connected to the grid; wherein the distribution network switch includes a tie switch and a section switch; When the power equipment to be connected to the grid is a switch cabinet to be connected to the grid, the switch cabinet to be connected to the grid controls the closing of the medium-voltage switchgear of the switch cabinet to be connected to the grid according to the closing operation signal, thereby realizing the secondary grid connection of the medium-voltage power generation vehicle and the switch cabinet to be connected to the grid; wherein, the medium-voltage switchgear includes: a medium-voltage circuit breaker and a load switch.

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