Series-parallel hybrid flexible interconnection device and operation method thereof
By using a series-parallel hybrid flexible interconnection device and a regulating branch composed of multiple switching units, the problem of low power supply reliability in existing flexible interconnection devices during faults is solved, achieving fault-tolerant operation and high-reliability power supply.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA ELECTRIC POWER RESEARCH INSTITUTE CO LTD
- Filing Date
- 2025-12-05
- Publication Date
- 2026-04-17
AI Technical Summary
Existing flexible interconnection devices suffer from reduced power supply reliability in the distribution network and cannot operate in a fault-tolerant manner when the on-load regulating switch fails.
A series-parallel hybrid flexible interconnection device is adopted, including a first transformer, a second transformer, and a switch array regulating mechanism. Through the regulating branch composed of multiple switch units, fault-tolerant operation is achieved, and power supply reliability is improved.
Even if any switch unit fails, the device will not be taken out of operation, which improves the power supply reliability and regulation accuracy of the distribution network and meets the needs of different scenarios.
Smart Images
Figure CN121886571A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of flexible AC power distribution technology, specifically to a series-parallel hybrid flexible interconnection device and its operation method. Background Technology
[0002] With the large-scale integration of distributed photovoltaic power, electric vehicles, and various types of energy storage, the distribution network is gradually transforming into a comprehensive source-grid-load-storage network, significantly increasing the requirements for power supply reliability and operational flexibility. Flexible interconnection systems, as a key means to address these needs, can achieve shock-free interconnection of distribution lines and flexible power flow adjustment.
[0003] To achieve interconnection, related technologies typically employ interconnection devices such as phase-shifting transformers and Sensing transformers. These devices regulate the secondary windings of the parallel transformers through a regulating mechanism, creating combined voltages of different amplitudes and phases. The interconnection device is then connected in series with the feeder to regulate the power flow of the distribution line. The regulating mechanism uses on-load tap changers; however, because on-load tap changers lack fault-tolerant operation capabilities, a failure of any tap changer within the regulating mechanism will cause the interconnection device to shut down, resulting in the distribution network reverting to radial operation and reducing power supply reliability. Summary of the Invention
[0004] To address the problem of low power supply reliability in existing technologies, this application provides a series-parallel hybrid flexible interconnection device, which may include a first transformer, a second transformer, and a switch array regulating mechanism.
[0005] The first transformer is connected in series with the power distribution line, the second transformer is connected in parallel with the power distribution line, and the switch array regulating mechanism is connected to the second transformer.
[0006] The switch array adjustment mechanism includes multiple parallel adjustment branches, and each adjustment branch includes a first switch unit and a second switch unit connected in series.
[0007] In some possible implementations, the first switching unit may be a circuit breaker, a mechanical switch, or a semiconductor device.
[0008] The second switching unit uses a circuit breaker, mechanical switch, or semiconductor device.
[0009] In some other possible implementations, the first transformer includes a first primary winding and a first secondary winding. The first primary winding is coupled to the first secondary winding.
[0010] For example, the second transformer includes a second primary winding, a second secondary winding, a third secondary winding, and a fourth secondary winding.
[0011] The second, third, and fourth secondary windings are all coupled to the second primary winding.
[0012] Furthermore, this application also provides a method for operating a series-parallel hybrid flexible interconnection device, which may include: Retrieve the narrowly defined and broadly defined available gears of the hybrid series-parallel flexible interconnect device.
[0013] If there is a narrowly available operating position in the real-time operation mode of the series-parallel hybrid flexible interconnection device, the device will switch from the real-time operating position to the narrowly available position and continue to operate.
[0014] If the real-time operating position of the series-parallel hybrid flexible interconnection device does not have a narrowly defined available position but has a broadly defined available position, the power flow deviation rate of the series-parallel hybrid flexible interconnection device under the broadly defined available position is calculated based on the actual power value of the series-parallel hybrid flexible interconnection device under the broadly defined available position, and the series-parallel hybrid flexible interconnection device is controlled based on the power flow deviation rate of the series-parallel hybrid flexible interconnection device under the broadly defined available position.
[0015] In one possible implementation, the retrieval of narrowly and broadly available slots for a hybrid series-parallel flexible interconnect device includes: In the event of a failure in any switching unit of the series-parallel hybrid flexible interconnection device, a search algorithm is used to retrieve the narrowly defined and broadly defined available positions of the series-parallel hybrid flexible interconnection device under the real-time operating position.
[0016] Furthermore, if the following conditions are met: Then, the first available gear is the narrowly defined available gear in the real-time operating gear. Among them, , , This indicates the output voltage of the second secondary winding of phase A, phase B, and phase C of the second transformer in the real-time operating position of the series-parallel hybrid flexible interconnection device. , , This indicates the output voltage of the second secondary winding of phase A, phase B, and phase C of the second transformer in the first available range of the series-parallel hybrid flexible interconnection device.
[0017] If satisfied Then, the second available gear is the generalized available gear of the real-time operating gear. Among them, , , This indicates the output voltage of the second secondary winding of phase A, phase B, and phase C of the second transformer in the real-time operating position of the series-parallel hybrid flexible interconnection device. , , This indicates the output voltage of the second secondary winding of phase A, phase B, and phase C of the second transformer in the second available tap position of the series-parallel hybrid flexible interconnection device. Represents the unit adjustment vector. j Represents the imaginary unit. p Represents the coefficients of the rotation vector.
[0018] Optionally, the power flow deviation rate of the series-parallel hybrid flexible interconnect device under the generalized available range satisfies:
[0019] in, This represents the power flow deviation rate of a hybrid series-parallel flexible interconnect device under the broadly available range. This represents the actual active power of a hybrid series-parallel flexible interconnect device under the broadly available range. This represents the actual reactive power value of a hybrid series-parallel flexible interconnection device under the broadly available range. This represents the active power command value of the distribution network where the series-parallel hybrid flexible interconnection device is located. This represents the reactive power command value of the distribution network where the series-parallel hybrid flexible interconnection device is located.
[0020] For example, controlling a series-parallel hybrid flexible interconnect device based on the power flow deviation rate of the hybrid flexible interconnect device under the generalized available range includes: If the power flow deviation rate of the series-parallel hybrid flexible interconnection device under the generalized available range is greater than the preset power deviation threshold, the series-parallel hybrid flexible interconnection device will be taken out of operation.
[0021] If the power flow deviation rate of the series-parallel hybrid flexible interconnection device under the generalized available range is less than or equal to the preset power deviation threshold, the series-parallel hybrid flexible interconnection device will switch to the generalized available range with the smallest power flow deviation rate and continue to operate.
[0022] Compared with the prior art, the beneficial effects of this application are as follows: The series-parallel hybrid flexible interconnection device provided in this application may include a first transformer, a second transformer, and a switch array regulating mechanism. The first transformer is connected in series with the distribution line, the second transformer is connected in parallel with the distribution line, and the switch array regulating mechanism is connected to the second transformer. The switch array regulating mechanism includes multiple parallel regulating branches, each of which includes a first switch unit and a second switch unit connected in series. This application, through a switch array regulating mechanism composed of multiple first switch units and multiple second switch units, enables fault-tolerant operation of the series-parallel hybrid flexible interconnection device. Even if any switch unit fails, it will not directly cause the series-parallel hybrid flexible interconnection device to shut down, thus improving the power supply reliability of the distribution network.
[0023] In this application, both the first and second switching units can be circuit breakers, mechanical switches, or semiconductor devices. When a narrowly defined available tap exists, the system can switch from the real-time operating tap to the narrowly defined available tap, maintaining the continued normal operation of the series-parallel hybrid flexible interconnection device, thereby further improving the power supply reliability of the distribution network where the series-parallel hybrid flexible interconnection device is located.
[0024] In this application, the first and second switching units can be flexibly selected according to the application scenarios of the series-parallel hybrid flexible interconnection device, taking into account the requirements for the response speed, overcurrent capacity, and withstand voltage of the device, so as to meet the differentiated needs of different scenarios for technical economy and regulation performance.
[0025] This application does not require additional backup redundant modules. While meeting the required adjustment accuracy, it improves the fault-tolerant operation capability of the series-parallel hybrid flexible interconnection device under fault conditions, providing technical support for improving the power supply reliability of the distribution network. It has significant engineering application value and promotion prospects. Attached Figure Description
[0026] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0027] Figure 1 This is a schematic structural diagram of a series-parallel hybrid flexible interconnection device in the embodiments of this application; Figure 2 This is a schematic structural diagram of a switch array adjustment mechanism in an embodiment of this application; Figure 3 This is a schematic flowchart illustrating an operation method of a series-parallel hybrid flexible interconnection device in this application. Figure 4 This is a schematic diagram illustrating the narrowly defined and broadly defined available gear positions in the embodiments of this application; Figure 5 This is a schematic flowchart illustrating an operation method of a series-parallel hybrid flexible interconnection device in this application. Detailed Implementation
[0028] The technical solutions in this application will now be described with reference to the accompanying drawings.
[0029] The terms "first," "second," etc., used in the specification, embodiments, claims, and drawings of this application are for distinguishing purposes only and should not be construed as indicating or implying relative importance or order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, such as including a series of steps or units. A method, system, product, or apparatus is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or apparatuses.
[0030] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.
[0031] Example 1 Embodiment 1 of this application provides a series-parallel hybrid flexible interconnection device (hereinafter referred to as the device), such as Figure 1 As shown. The device 100 includes a first transformer 1, a second transformer 2, and a switch array adjustment mechanism 3.
[0032] The first transformer 1 is connected in series with the power distribution line, and the second transformer 2 is connected in parallel with the power distribution line. The switch array regulating mechanism 3 is connected to the second transformer 2. Therefore, the first transformer 1 can be called a series transformer, and the second transformer 2 can be called a parallel transformer.
[0033] Figure 1 middle, U 1A ,U 1B , U 1C This indicates the three-phase voltage at the first terminal of the device. U 2A , U 2B , U 2C This indicates the three-phase voltage at the second terminal of the device. U TA , U TB , U TC These represent A-phase series transformer, B-phase series transformer, and C-phase series transformer, respectively. U PA , U PB , U PC These represent the parallel transformers of phase A, phase B, and phase C, respectively. Aa represents the second secondary winding of phase A of the second transformer, Ab represents the third secondary winding of phase A of the second transformer, and Ac represents the fourth secondary winding of phase A of the second transformer. Ba represents the second secondary winding of phase B of the second transformer, Bb represents the third secondary winding of phase B of the second transformer, and Bc represents the fourth secondary winding of phase B of the second transformer. Ca represents the second secondary winding of phase C of the second transformer, Cb represents the third secondary winding of phase C of the second transformer, and Cc represents the fourth secondary winding of phase C of the second transformer. It should be noted that the output voltage of the series-parallel hybrid flexible interconnection device is symmetrical across all three phases.
[0034] In some possible implementations, the first transformer (i.e., the A-phase series transformer, the B-phase series transformer, and the C-phase series transformer) includes a first primary winding and a first secondary winding. The first primary winding is coupled to the first secondary winding. That is, the first transformer can be a two-winding transformer. The first transformer can connect the voltage vector of the parallel transformer combination in series and superimpose it onto the distribution line according to a set turns ratio, isolating the distribution network from the switch array regulating mechanism.
[0035] For example, the second transformer (i.e., the parallel transformers of phase A, phase B, and phase C) includes a second primary winding, a second secondary winding, a third secondary winding, and a fourth secondary winding. The second, third, and fourth secondary windings are all coupled to the second primary winding. In other words, the second transformer can be a four-winding transformer. The primary winding is energized by the system phase voltage, and the three secondary windings (such as Aa, Ab, and Ac of phase A) all have taps, allowing for different turns combinations via a switch array.
[0036] Optional, such as Figure 2As shown, the switch array adjustment mechanism 3 includes multiple parallel adjustment branches.
[0037] Each regulating branch includes a first switching unit S1 and a second switching unit S2 connected in series.
[0038] Optionally, the first switching unit S1 and the second switching unit S2 can be selected from circuit breakers, mechanical switches, or semiconductor devices according to the application scenario's requirements for response speed, overcurrent capacity, withstand voltage capacity, etc., to meet the differentiated needs of different scenarios for technical economy and regulation performance. By controlling the opening and closing of the switching units, the connection mode of the secondary winding of the parallel transformer can be flexibly combined to realize the tap adjustment function.
[0039] Example 2 Embodiment 2 of this application provides an operation method for a series-parallel hybrid flexible interconnection device. For example... Figure 3 As shown, the running method 200 may include: Step S1: Retrieve the narrowly defined and broadly defined available positions of the series-parallel hybrid flexible interconnect device.
[0040] Step S2: If there is a narrowly available operating position in the real-time operation mode of the series-parallel hybrid flexible interconnection device, the series-parallel hybrid flexible interconnection device switches from the real-time operating position to the narrowly available position and continues to operate.
[0041] Step S3: If the real-time operating position of the series-parallel hybrid flexible interconnection device does not have a narrowly defined available position but has a broadly defined available position, calculate the power flow deviation rate of the series-parallel hybrid flexible interconnection device under the broadly defined available position based on the actual power value of the series-parallel hybrid flexible interconnection device under the broadly defined available position, and control the series-parallel hybrid flexible interconnection device based on the power flow deviation rate of the series-parallel hybrid flexible interconnection device under the broadly defined available position.
[0042] In one possible implementation, step S1 involves retrieving both the narrowly defined and broadly defined available slots for a hybrid series-parallel flexible interconnect device, including: In the event of a failure in any switching unit of a series-parallel hybrid flexible interconnection device, a search algorithm (which may be a pruning search algorithm, an enumeration algorithm, a depth-first search algorithm, etc.) is used to retrieve the narrowly defined and broadly defined available positions of the series-parallel hybrid flexible interconnection device under the real-time operating position.
[0043] Furthermore, if the following conditions are met: Then, the first available gear is the narrowly defined available gear in the real-time operating gear. Among them, , , This indicates the output voltages of the second secondary windings of phase A, phase B, and phase C of the second transformer in the real-time operating position of the series-parallel hybrid flexible interconnection device. , , This indicates the output voltage of the second secondary winding of phase A, phase B, and phase C of the second transformer in the first available position of the series-parallel hybrid flexible interconnection device.
[0044] In other words, for the first combination of switching units corresponding to the real-time operating position of the series-parallel hybrid flexible interconnection device, it is necessary to check whether there exists a first available position composed of any second combination of different switching units that satisfies the requirement. If it exists, then the first available gear is the narrowly defined available gear in the real-time operating gear.
[0045] If satisfied Then, the second available gear is the generalized available gear of the real-time operating gear. Among them, , , This indicates the output voltage of the second secondary winding of phase A, phase B, and phase C of the second transformer in the second available tap position of the series-parallel hybrid flexible interconnection device. Represents the unit adjustment vector. j Represents the imaginary unit. p The coefficients of the rotation vector are represented. .
[0046] In other words, for the first combination of switching units corresponding to the current operating position of the series-parallel hybrid flexible interconnection device, it is necessary to search whether there exists a second available position composed of any different second combination of switching units that satisfies the requirement. If it exists, then the second available gear is the generalized available gear of the currently running gear.
[0047] The specific process of determining the first available gear as the narrowly defined available gear for real-time operation and the second available gear as the broadly defined available gear for real-time operation in the embodiments of this application is taken as an example of phase A. The same applies to phases B and C. The embodiments of this application do not limit this process.
[0048] You can refer to the narrowly defined and broadly defined available gears. Figure 4 . Figure 4 In the diagram, the green circle at the center of the small hexagon indicates the real-time operating gear, which coincides with the narrowly defined available gear. The red circle indicates the broadly defined available gear.
[0049] Optionally, in step S2, the power flow deviation rate of the series-parallel hybrid flexible interconnection device under the generalized available range satisfies:
[0050] in, This represents the power flow deviation rate of a hybrid series-parallel flexible interconnect device under the broadly available range. This represents the actual active power of a hybrid series-parallel flexible interconnect device under the broadly available range. This represents the actual reactive power value of a hybrid series-parallel flexible interconnection device under the broadly available range. This represents the active power command value of the distribution network where the series-parallel hybrid flexible interconnection device is located. This represents the reactive power command value of the distribution network where the series-parallel hybrid flexible interconnection device is located.
[0051] For example, in step S3, controlling the series-parallel hybrid flexible interconnect device based on the power flow deviation rate of the series-parallel hybrid flexible interconnect device under the generalized available range includes: If the power flow deviation rate of a series-parallel hybrid flexible interconnection device is within the broadly available range... Greater than the preset power deviation threshold That is, satisfying > If the series-parallel hybrid flexible interconnection device is shut down, it will be taken out of operation.
[0052] If the power flow deviation rate of the series-parallel hybrid flexible interconnection device is less than or equal to the preset power deviation threshold under the generalized available range, then it satisfies the requirement. ≤ Then, the series-parallel hybrid flexible interconnection device switches to the generalized available gear with the smallest power flow deviation rate and continues to operate.
[0053] Of course, the operating method provided in this application can also be followed Figure 5 The flowchart implementation can specifically include the following steps: Step S1: A fault occurs in any switching unit of the series-parallel hybrid flexible interconnection device.
[0054] Step S2: Search for available gears under the current running gear.
[0055] Step S3: Determine if there is a narrowly defined available gear. If yes, proceed to step S8; otherwise, proceed to step S4.
[0056] Step S4: Determine if a generalized available gear exists. If yes, proceed to step S5. Otherwise, the series-parallel hybrid flexible interconnection device will exit operation.
[0057] Step S5: Calculate the power flow deviation .
[0058] Step S6: Determine if the power flow deviation is satisfied. Less than or equal to the power deviation threshold If yes, proceed to step S7; otherwise, exit the series-parallel hybrid flexible interconnection device.
[0059] Step S7: The series-parallel hybrid flexible interconnection device switches to the generalized available gear with the smallest power flow deviation rate and continues to operate.
[0060] Step S8: Switch from the real-time running gear to the narrowly defined available gear and continue running.
[0061] The above are merely embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application shall be included within the scope of the claims of this application pending approval.
Claims
1. A series-parallel hybrid flexible interconnection device, characterized in that, Includes a first transformer, a second transformer, and a switch array regulating mechanism; The first transformer is connected in series with the power distribution line, the second transformer is connected in parallel with the power distribution line, and the switch array adjustment mechanism is connected to the second transformer; The switch array adjustment mechanism includes multiple parallel adjustment branches, and each adjustment branch includes a first switch unit and a second switch unit connected in series.
2. The series-parallel hybrid flexible interconnection device according to claim 1, characterized in that, The first switching unit uses a circuit breaker, a mechanical switch, or a semiconductor device; The second switching unit employs a circuit breaker, a mechanical switch, or a semiconductor device.
3. The series-parallel hybrid flexible interconnection device according to claim 1, characterized in that, The first transformer includes a first primary winding and a first secondary winding; the first primary winding is coupled to the first secondary winding.
4. The series-parallel hybrid flexible interconnection device according to claim 1, characterized in that, The second transformer includes a second primary winding, a second secondary winding, a third secondary winding, and a fourth secondary winding; The second secondary winding, the third secondary winding, and the fourth secondary winding are all coupled to the second primary winding.
5. A method for operating a series-parallel hybrid flexible interconnection device as described in any one of claims 1 to 4, characterized in that, include: Search for the narrowly defined and broadly defined available ranges of hybrid series-parallel flexible interconnect devices; If the real-time operating mode of the series-parallel hybrid flexible interconnection device has the narrowly available mode, the series-parallel hybrid flexible interconnection device switches from the real-time operating mode to the narrowly available mode and continues to operate; If the real-time operating position of the series-parallel hybrid flexible interconnection device does not have the narrowly defined available position but has the broadly defined available position, the power flow deviation rate of the series-parallel hybrid flexible interconnection device under the broadly defined available position is calculated based on the actual power value of the series-parallel hybrid flexible interconnection device under the broadly defined available position, and the series-parallel hybrid flexible interconnection device is controlled based on the power flow deviation rate of the series-parallel hybrid flexible interconnection device under the broadly defined available position.
6. The operating method according to claim 5, characterized in that, The narrowly defined and broadly defined available ranges of the retrieval serial-parallel hybrid flexible interconnect device include: In the event of a failure in any switching unit of the series-parallel hybrid flexible interconnection device, a search algorithm is used to retrieve the narrowly defined and broadly defined available positions of the series-parallel hybrid flexible interconnection device under the real-time operating position.
7. The operating method according to claim 6, characterized in that, If the following conditions are met: Then, the first available gear is the narrowly defined available gear of the real-time operating gear; wherein, , , This indicates the output voltage of the second secondary winding of phase A, phase B, and phase C of the second transformer in the real-time operating position of the series-parallel hybrid flexible interconnection device. , , This indicates the output voltage of the second secondary winding of phase A, phase B, and phase C of the second transformer in the first available range of the series-parallel hybrid flexible interconnection device.
8. The operating method according to claim 6, characterized in that, If satisfied Then, the second available gear is the generalized available gear of the real-time operating gear; wherein, , , This indicates the output voltage of the second secondary winding of phase A, phase B, and phase C of the second transformer in the real-time operating position of the series-parallel hybrid flexible interconnection device. , , This indicates the output voltage of the second secondary winding of phase A, phase B, and phase C of the second transformer in the second available range of the series-parallel hybrid flexible interconnection device. Represents the unit adjustment vector. j Represents the imaginary unit. p Represents the coefficients of the rotation vector.
9. The operating method according to claim 5, characterized in that, The power flow deviation rate of the series-parallel hybrid flexible interconnection device under the generalized available range satisfies: in, This represents the power flow deviation rate of the series-parallel hybrid flexible interconnect device under the generalized available range. This represents the actual active power value of the series-parallel hybrid flexible interconnection device under the generalized available range. This represents the actual reactive power value of the series-parallel hybrid flexible interconnection device under the generalized available range. This represents the active power command value of the distribution network where the series-parallel hybrid flexible interconnection device is located. This represents the reactive power command value of the distribution network where the series-parallel hybrid flexible interconnection device is located.
10. The operating method according to claim 5, characterized in that, The step of controlling the series-parallel hybrid flexible interconnection device based on the power flow deviation rate of the series-parallel hybrid flexible interconnection device under the generalized available range includes: If the power flow deviation rate of the series-parallel hybrid flexible interconnection device under the generalized available range is greater than the preset power deviation threshold, the series-parallel hybrid flexible interconnection device will be taken out of operation. If the power flow deviation rate of the series-parallel hybrid flexible interconnection device under the generalized available position is less than or equal to the preset power deviation threshold, the series-parallel hybrid flexible interconnection device switches to the generalized available position with the smallest power flow deviation rate and continues to operate.