A power supply restoration strategy and system for a flexible interconnected distribution network

Abstract

The present invention discloses a power supply restoration strategy and system for a flexible interconnected distribution network, which relates to the field of power system control, including obtaining distribution network data, connecting power supply areas to form a flexible interconnected distribution network FIDN through a flexible soft switch SOP, and constructing a distributed power generation model DG; switching the control mode of the flexible soft switch SOP according to the flexible interconnected distribution network FIDN to restore power supply, thereby achieving uninterrupted power supply to the power-lost area; formulating constraint conditions for node voltage amplitude under an uncertain environment based on a chance constraint method; reconstructing the distribution network topology according to the optimal topology and switching the flexible soft switch SOP control mode to restore power supply, thereby achieving power supply restoration of the flexible interconnected distribution network FIDN. The present invention provides a power supply restoration strategy for a flexible interconnected distribution network, establishes a stochastic optimization model for fault recovery of a flexible interconnected distribution network, and improves the efficiency of power restoration.

Description

Technical Field

[0001] The present invention relates to the field of power system control, and in particular to a power supply restoration strategy and system for a flexible interconnected distribution network. Background Art

[0002] Flexible interconnected distribution networks offer enhanced load transfer capabilities to faulty areas during fault conditions, enabling better power restoration. On the other hand, with the increasing proportion of distributed generation (DG) connected to the grid, the presence of renewable energy and load uncertainty can cause significant fluctuations in feeder power and voltage limits. Continuing to adhere to the original deterministic constraints during distribution network fault recovery would hinder the full utilization of distributed generation and make the recovery process more conservative. Therefore, fully leveraging the self-healing control support capabilities of the SOP and developing efficient power restoration strategies is crucial. Summary of the Invention

[0003] In view of the problem that when a high proportion of distributed power sources are connected to the grid during distribution network fault recovery, the original deterministic constraints of the existing technology are not fully matched with the existing distribution network fault recovery, the present invention is proposed.

[0004] Therefore, the problem to be solved by the present invention is how to provide a method for exploring the self-healing control support capability of SOP, achieving full matching of deterministic constraints with existing distribution network faults when a high proportion of distributed power sources are connected to the grid, and improving power supply recovery efficiency.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] In the first aspect, an embodiment of the present invention provides a power supply restoration strategy for a flexible interconnected distribution network, which includes acquiring distribution network data, connecting power supply areas through flexible soft switches SOP to form a flexible interconnected distribution network FIDN, and constructing a distributed power generation model DG; switching the control mode of the flexible soft switch SOP according to the flexible interconnected distribution network FIDN to restore power supply, thereby realizing uninterrupted power supply to the power-lost area; formulating constraint conditions for node voltage amplitudes under an uncertain environment based on a chance constraint method; reconstructing the distribution network topology according to the optimal topology and switching the flexible soft switch SOP control mode to restore power supply, thereby realizing power supply restoration of the flexible interconnected distribution network FIDN.

[0007] As a preferred solution for the power supply restoration strategy of a flexible interconnected distribution network described in the present invention, the characteristics of the flexible soft switch SOP include uninterrupted power transfer and intelligent regulation, connecting the tails of two power supply areas to form a flexible interconnected distribution network with flexible closed-loop operation; the power supply restoration strategy of the flexible interconnected distribution network FIDN takes the weighted sum of the maximum recovery of active load of normal nodes and the minimum system operation loss as the objective function, includes multiple constraints, and establishes a random optimization model for power supply restoration of the flexible interconnected distribution network FIDN.

[0008] As a preferred solution of the power supply restoration strategy of a flexible interconnected distribution network described in the present invention, the power supply restoration strategy of the flexible interconnected distribution network FIDN includes the following steps: obtaining the network parameters, operating fault parameters and distributed power generation parameters of the flexible interconnected distribution network FIDN after the disaster, and judging the location and operating status of the power-off area; judging whether the flexible soft switch SOP switches the control mode according to the location of the power-off area; optimizing the power supply restoration topology of the flexible interconnected distribution network FIDN according to the fault location and the distributed power generation parameters, and selecting the chance constraint method to establish the constraint conditions of the node voltage amplitude under the uncertain environment; transforming the power supply restoration model into a nonlinear constraint condition to obtain a mixed integer second-order cone programming model; reconstructing the network of the flexible interconnected distribution network FIDN according to the optimal network topology, connecting the power-off area and the upper power grid through a tie switch, and judging whether the flexible soft switch SOP switches the control mode.

[0009] As a preferred solution of the power supply restoration strategy of a flexible interconnected distribution network described in the present invention, the obtaining of network parameters, operating fault parameters and distributed power generation parameters of the post-disaster flexible interconnected distribution network FIDN and the determination of the location and operating conditions of the power-off area include the following steps: identifying the fault point according to the grid operating status provided by the grid data acquisition and monitoring control system, and calling the grid below the fault point the power-off area; constructing a distributed power source DG power generation model and determining whether there is a distributed power source DG in the power-off area; if so, determining whether the power-off area can form an island and operate independently based on the distributed power source DG power generation parameters and model; if not, the power-off area cannot operate independently; and determining whether there is a node in the power-off area connected to one side of the flexible soft switch SOP.

[0010] As a preferred solution of the power supply restoration strategy of a flexible interconnected distribution network described in the present invention, wherein: the determination of whether the flexible soft switch SOP switches the control mode according to the location of the power failure area includes the following steps: the control mode of the flexible soft switch SOP is initialized to P / QV DC / Q mode, and construct a mathematical model of the flexible soft switch SOP; divide the power-off area into the following scenarios according to the location of the power-off area: the power-off area is disconnected from the upper-level power grid but can operate independently, and there is a node in the power-off area that is connected to one side of the flexible soft switch SOP; the power-off area is disconnected from the upper-level power grid but can operate independently, and there is no node in the power-off area that is connected to one side of the flexible soft switch SOP; the power-off area is disconnected from the upper-level power grid and cannot operate independently, and there is a node in the power-off area that is connected to one side of the flexible soft switch SOP; the power-off area is disconnected from the upper-level power grid and cannot operate independently, and there is no node in the power-off area that is connected to one side of the flexible soft switch SOP; judge whether the control mode of the flexible soft switch SOP changes according to the scenario. If the power-off area scenario is that the power-off area is disconnected from the upper-level power grid and cannot operate independently, and there is a node in the power-off area that is connected to one side of the flexible soft switch SOP, then the control mode of the flexible soft switch SOP changes from P / QV DC / Q mode conversion to V / fV DC / Q mode, the rest of the scenes remain unchanged.

[0011] As a preferred solution of the power supply restoration strategy of a flexible interconnected distribution network described in the present invention, the power supply restoration model is transformed into a nonlinear constraint condition to obtain a mixed integer second-order cone programming model, which includes the following steps: performing a rotating cone relaxation on the nonlinear expression of the flexible soft switch SOP operation constraint condition to obtain a linear expression; performing a rotating cone relaxation on the nonlinear expression of the power flow constraint condition in the flexible interconnected distribution network FIDN to obtain a linear expression; using the sample mean approximation method and Monte Carlo sampling to transform the nonlinear constraint condition of the chance constraint into a linear expression.

[0012] As a preferred solution of the power supply restoration strategy of a flexible interconnected distribution network described in the present invention, wherein: the network reconstruction of the flexible interconnected distribution network FIDN according to the optimal network topology includes the following steps: determining the optimal topology according to the stochastic optimization model of the power supply restoration of the flexible interconnected distribution network FIDN, and reconstructing the network of the flexible interconnected distribution network FIDN through the tie switch; searching whether there is a line connected to the upper-level power grid at the node connected to the flexible soft switch SOP; if so, the control mode of the flexible soft switch SOP is P / QV DC / Q mode, if it does not exist, the soft switch SOP control mode is V / fV DC / Q mode.

[0013] Secondly, in order to further solve the security problems existing in the recovery of distribution network faults, the present invention provides a power supply restoration system for a flexible interconnected distribution network in an embodiment, which includes: a judgment module for obtaining data of the flexible interconnected distribution network FIDN after the disaster and judging whether the flexible soft switch SOP switches the control mode; a model construction module for constructing a random optimization model for power supply restoration of the flexible interconnected distribution network FIDN according to the objective function and constraints; a power supply restoration module for performing network reconstruction of the flexible interconnected distribution network FIDN according to the optimal network topology, and judging whether the flexible soft switch SOP switches the control mode to achieve power supply restoration of the flexible interconnected distribution network FIDN.

[0014] In a third aspect, an embodiment of the present invention provides a computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: when the computer program is executed by the processor, any step of a power supply restoration strategy for a flexible interconnected distribution network as described in the first aspect of the present invention is implemented.

[0015] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program is executed by a processor, it implements any step of a power supply restoration strategy for a flexible interconnected distribution network as described in the first aspect of the present invention.

[0016] The beneficial effects of the present invention are as follows: the present invention provides a power supply restoration strategy for a flexible interconnected distribution network and establishes a stochastic optimization model for fault recovery of a flexible interconnected distribution network, which is used to solve the problem of insufficient matching between the original deterministic constraints and the existing distribution network fault recovery when a high proportion of distributed power sources are connected to the grid, thereby improving the efficiency of power supply restoration. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort. Among them:

[0018] Figure 1 This is a power restoration flow chart of the present invention in Example 1.

[0019] Figure 2 This is a diagram of the power supply restoration system of the present invention in Example 2.

[0020] Figure 3 This is a diagram of the system reconstruction result of the present invention in Example 2. DETAILED DESCRIPTION

[0021] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0022] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0023] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0024] Example 1

[0025] Reference Figure 1 , which is the first embodiment of the present invention, provides a power supply restoration strategy for a flexible interconnected distribution network, including the following steps:

[0026] S1: Obtain distribution network data, connect the power supply areas through flexible soft switches (SOPs) to form a flexible interconnected distribution network (FIDN), and build a distributed power generation model (DG).

[0027] Preferably, the features of the flexible soft switch SOP include uninterrupted power transfer and intelligent regulation, connecting the tail ends of the two power supply areas to form a flexible interconnected distribution network with flexible closed-loop operation.

[0028] Preferably, the power supply restoration strategy of the flexible interconnected distribution network FIDN takes the weighted sum of maximizing the recovery of the active load of normal nodes and minimizing the system operation loss as the objective function, includes multiple constraints, and establishes a stochastic optimization model for power supply restoration of the flexible interconnected distribution network FIDN.

[0029] Specifically, such as Figure 1 The figure shows a schematic diagram of the power supply restoration process of the present invention. The power supply restoration strategy of the flexible interconnected distribution network FIDN includes the following steps: obtaining the network parameters, operating fault parameters and distributed power generation parameters of the flexible interconnected distribution network FIDN after the disaster, and determining the location and operating status of the power outage area.

[0030] The flexible soft switch SOP is judged whether to switch the control mode according to the position of the power-off area.

[0031] According to the fault location and distributed generation parameters, the power supply restoration topology of the flexible interconnected distribution network FIDN is optimized, and the chance constraint method is selected to establish the constraint conditions of the node voltage amplitude under uncertainty environment.

[0032] The power restoration model is transformed into a mixed integer second-order cone programming model by transforming nonlinear constraints.

[0033] The network of the flexible interconnected distribution network FIDN is reconstructed according to the optimal network topology, the power-off area and the upper power grid are connected through the tie switch, and it is determined whether the flexible soft switch SOP switches the control mode.

[0034] Furthermore, obtaining the network parameters, operating fault parameters and distributed power generation parameters of the post-disaster flexible interconnected distribution network FIDN and judging the location and operating status of the power-off area includes the following steps: identifying the fault point according to the grid operating status provided by the grid data acquisition and monitoring control system, and calling the grid below the fault point the power-off area.

[0035] Construct a distributed power generation DG power generation model and determine whether there is a distributed power generation DG in the power outage area. If so, determine whether the power outage area can form an island and operate independently based on the distributed power generation DG power generation parameters and model. If not, the power outage area cannot operate independently.

[0036] Determine whether there is a node in the power-off area connected to one side of the flexible soft switch SOP.

[0037] S2: Power supply is restored according to the control mode of the flexible soft switch SOP switched by the flexible interconnected distribution network FIDN, so as to achieve uninterrupted power supply to the power-lost area.

[0038] Specifically, judging whether the flexible soft switch SOP switches the control mode according to the position of the power-off area includes the following steps: the control mode of the flexible soft switch SOP is initialized to P / QV DC / Q mode, and construct a mathematical model of the flexible soft switch SOP. The mathematical model calculation formula of the flexible soft switch SOP is as follows:

[0039] P SOP,i +P SOP,j +P SOP,L,i +P SOP,L,j =0

[0040]

[0041]

[0042]

[0043] Among them, P SOP,i is the active power injected by SOP at node i; P SOP,j is the active power injected by SOP at node j; Q SOP,i is the reactive power injected by SOP at node i; Q SOP,jA is the reactive power injected by SOP at node j; SOP,i is the loss coefficient of SOP; A SOP,j is the loss coefficient of SOP; P SOP,L,i is the converter loss at node i; P SOP,L,j is the converter loss at node j; S SOP,i is the capacity of the converter connected to node j; S SOP,j is the capacity of the converter connected to node j.

[0044] The power outage area is divided into the following scenarios according to its location: the power outage area is disconnected from the upper-level power grid but can operate independently, and there is a node in the power outage area connected to the SOP side of the flexible soft switch; the power outage area is disconnected from the upper-level power grid but can operate independently, and there is no node in the power outage area connected to the SOP side of the flexible soft switch; the power outage area is disconnected from the upper-level power grid and cannot operate independently, and there is a node in the power outage area connected to the SOP side of the flexible soft switch; the power outage area is disconnected from the upper-level power grid and cannot operate independently, and there is no node in the power outage area connected to the SOP side of the flexible soft switch.

[0045] Determine whether the control mode of the flexible soft switch SOP changes according to the scenario. If the power failure area scenario is that the power failure area is disconnected from the upper level power grid and cannot operate independently, and there is a node in the power failure area connected to one side of the flexible soft switch SOP, the control mode of the flexible soft switch SOP changes from P / QV DC / Q mode conversion to V / fV DC / Q mode, the rest of the scenes remain unchanged.

[0046] S3: Formulate the constraint conditions of node voltage amplitude under uncertainty environment based on the chance constraint method. Preferably, the objective function of the stochastic optimization model of power supply restoration of flexible interconnected distribution network FIDN is as follows:

[0047] min F=-λ D f D +λ R f R

[0048]

[0049]

[0050] Among them, f D The system active load is restored; f R is the system loss; D f D The weight coefficient of R f R The weight coefficient and λ D >>λR ; N is the set of all nodes; B is the set of all branches; P Load,i is the active power consumed by the load at node i; r ij is the resistance value of branch ij; is the square of the current amplitude on branch ij; P SOP,L,i is the loss caused by the SOP connected to node i; α i is the load factor on recoverable node i, α i ∈[0,1];Ω i is the importance coefficient of the load at location i, where the first-level load is 3, the second-level load is 2, and the third-level load is 1.

[0051] Furthermore, the topology constraint calculation formula is as follows:

[0052] B n ∈V,n∈{1,2}

[0053] Among them, B n is the network topology of the nth power supply area; V is the radial network topology.

[0054] Furthermore, the power flow constraint calculation formula is as follows:

[0055]

[0056]

[0057]

[0058] P i =P DG,i +P SOP,i -α i P Load,i

[0059] Q i =Q DG,i +Q SOP,i -α i Q Load,i

[0060] Among them, V i is the voltage amplitude at node i; V j is the voltage amplitude at node j; P ij is the active power flowing from node i to node j on branch ij; Q ij is the reactive power flowing from node i to node j on branch ij; x ij is the reactance value of branch ij; P i is the sum of active power injected into node i; Q i is the sum of reactive power injected into node i; P DG,iis the active power injected by the distributed generation at node i; Q DG,i is the reactive power injected by the distributed generation at node i; Q Load,i is the reactive power consumed by the load at node i.

[0061] Furthermore, the calculation formula for distribution network operation constraints is as follows:

[0062] Pr{V i ≥V imin}≥β V

[0063] Pr{V i ≤V imax}≥β V

[0064]

[0065] Among them, V imin V is the minimum allowable value of the node voltage when the system is running; imax I is the maximum allowable value of the node voltage when the system is running; max is the maximum allowable value of the system branch current, Pr{·} is the chance constraint; β is the confidence level of the chance constraint, and its value range is [0,1].

[0066] Furthermore, the SOP operation constraints are in addition to the formula shown in the model, V / fV DC / Q mode also includes the following constraints:

[0067]

[0068]

[0069] in, is the SOP fault side control voltage; V o It is the minimum per-unit value of the fault-side node voltage, which is 1.0.

[0070] Furthermore, the calculation formula for the switching times constraint is as follows:

[0071] K T ≤K max

[0072] Among them, K T is the total number of switch actions during the reconstruction process; K max The maximum number of switch actions allowed during the reconstruction process.

[0073] Specifically, the power restoration model is transformed into a nonlinear constraint condition to obtain a mixed integer second-order cone programming model, which includes the following steps: the nonlinear expression of the flexible soft switch SOP operation constraint condition is subjected to rotating cone relaxation to obtain the linear expression as follows:

[0074]

[0075]

[0076]

[0077]

[0078] The nonlinear equation of the power flow constraint in the flexible interconnected distribution network FIDN is relaxed by rotating cone, and the linear equation is obtained as follows:

[0079]

[0080] Using the sample mean approximation method and Monte Carlo sampling, the chance constraint is transformed into a nonlinear constraint condition to obtain the linear formula as follows:

[0081] V imin -|V i,s |≤K·Z vmin,s

[0082] |V i,s |-V imax ≤K·Z vmax,s

[0083]

[0084]

[0085] Z vmin,s ,Z vmax,s ∈{0,1},s=1,2,…,N s

[0086] Among them, N s is the number of sampling scenes; V i,s is the voltage amplitude of node i in the sth sampling scenario; K is a value that ensures that when Z vmin,s and Z vmax,s When it is 1, V imin -|V i,s |≤K·Z vmin,s and |V i,s |-V imax ≤K·Z vmax,s A positive value that must hold true; Z vmin,s = 0 means in the sth sampling scenario, V imin -|V i,s |≤0;Z vmin,s =1 for V i,s There are no restrictions.

[0087] S4: Reconstruct the distribution network topology according to the optimal topology and switch to the flexible soft switch SOP control mode to restore power supply, thereby realizing power supply restoration of the flexible interconnected distribution network FIDN.

[0088] Specifically, the network reconstruction of the flexible interconnected distribution network FIDN according to the optimal network topology includes the following steps: determining the optimal topology according to the flexible interconnected distribution network FIDN power supply restoration stochastic optimization model, and reconstructing the flexible interconnected distribution network FIDN network through the tie switch.

[0089] Search whether there is a line connected to the upper-level power grid at the node connected to the flexible soft switch SOP.

[0090] If it exists, the soft switch SOP control mode is P / QV DC / Q mode, if it does not exist, the soft switch SOP control mode is V / fV DC / Q mode.

[0091] This embodiment also provides a power supply restoration system for a flexible interconnected distribution network, including: a judgment module, used to obtain data of the flexible interconnected distribution network FIDN after a disaster, and determine whether the flexible soft switch SOP switches the control mode; a model construction module, used to construct a stochastic optimization model for power supply restoration of the flexible interconnected distribution network FIDN based on the objective function and constraints; a power supply restoration module, used to perform network reconstruction of the flexible interconnected distribution network FIDN according to the optimal network topology, and determine whether the flexible soft switch SOP switches the control mode to achieve power supply restoration of the flexible interconnected distribution network FIDN.

[0092] This embodiment also provides a computer device, which is suitable for a power supply restoration strategy of a flexible interconnected distribution network, including: a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute computer-executable instructions to implement a power supply restoration strategy of a flexible interconnected distribution network proposed in the above embodiment.

[0093] The computer device may be a terminal, comprising a processor, a memory, a communication interface, a display screen and an input device connected via a system bus. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device comprises a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner may be achieved through WIFI, an operator network, NFC (near field communication) or other technologies. The display screen of the computer device may be a liquid crystal display or an electronic ink display screen, and the input device of the computer device may be a touch layer covering the display screen, or a button, trackball or touchpad provided on the housing of the computer device, or an external keyboard, touchpad or mouse.

[0094] This embodiment also provides a storage medium having a computer program stored thereon, which, when executed by a processor, implements a power supply restoration strategy for a flexible interconnected distribution network as proposed in the above embodiment; the storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, disk or optical disk.

[0095] In summary, the present invention provides a power supply restoration strategy for a flexible interconnected distribution network and establishes a stochastic optimization model for fault recovery of a flexible interconnected distribution network, which is used to solve the problem of insufficient matching between the original deterministic constraints and the existing distribution network fault recovery when a high proportion of distributed power sources are connected to the grid, thereby improving the efficiency of power supply restoration.

[0096] Example 2

[0097] Reference Figure 2 and Figure 3This is the second embodiment of the present invention. Different from the first embodiment, in order to verify its beneficial effects, the present invention analyzes the power supply recovery capability from different confidence levels and different control modes of the flexible soft switch SOP based on the proposed strategy. In order to make the present invention clearer and more intuitive, a "hand-in-hand" IEEE-33 node network is constructed using a two-terminal flexible soft switch SOP for simulation verification.

[0098] like Figure 2 The figure shows the power supply restoration system of the present invention. Due to the uncertainty of wind power and photovoltaic power, which seriously affects the power supply restoration process of the system, the chance constraint method is selected for processing, and different confidence levels are selected for comparative analysis. By assuming that the 2-3 branch in the system fails, the wind power rated power is taken as 200kW, and the photovoltaic rated power is taken as 300kW. The specific research results are shown in Table 1.

[0099] Table 1 Comparison of power restoration results at different confidence levels

[0100]

[0101] like Figure 3 The figure shows the system reconstruction result of the present invention. By assuming that the 10-11 branch in the system fails and the wind power and photovoltaic parameters remain unchanged, the influence of the two SOP control modes on the power supply recovery of FIDN is verified. The specific scenarios are as follows: the load in the power supply area 1 is set to 0.7 times the original load, the load in the power supply area 2 remains unchanged, reconstruction occurs after the fault, and the SOP control mode is P / Q-VDC / Q control; the load in the power supply area 1 is set to 0.7 times the original load, the load in the power supply area 2 remains unchanged, no reconstruction occurs after the fault, and the SOP control mode is V / f-VDC / Q control; the load in the power supply area 1 remains unchanged, the load in the power supply area 2 is set to 0.7 times the original load, and reconstruction occurs after the fault, and the SOP control mode is P / Q-VDC / Q control; the load in the power supply area 1 remains unchanged, the load in the power supply area 2 is set to 0.7 times the original load, and reconstruction occurs after the fault, and the SOP control mode is V / f-VDC / Q control.

[0102] Table 2 shows the power restoration effect in the above scenario.

[0103] Table 2 Comparison of power restoration results in different scenarios

[0104]

[0105] In summary, examples have verified that the present invention can solve the uncertainty problem of distributed power sources DG in the flexible interconnected distribution network FIDN. Through different control modes of the flexible soft switch SOP, it is realized that when a fault occurs, the power-off area is first urgently restored using the V / f-VDC / Q control mode. After determining the optimal topology, the power-off area and the non-power-off area are reconstructed and connected, and the P / Q-VDC / Q control method is used to achieve more efficient power supply recovery.

[0106] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A power supply restoration strategy for a flexible interconnected distribution network, characterized by: include: Obtain distribution network data, connect the power supply areas through flexible soft switching (SOP) to form a flexible interconnected distribution network (FIDN), and build a distributed power generation (DG) model; Switching the control mode of the flexible soft switch SOP according to the flexible interconnected distribution network FIDN to restore power supply, thereby realizing uninterrupted power supply to the power-lost area; The constraint conditions of node voltage amplitude under uncertainty environment are formulated based on the chance constraint method; Reconstruct the distribution network topology according to the optimal topology and switch the flexible soft switch SOP control mode to restore power supply, thereby realizing power supply restoration of the flexible interconnected distribution network FIDN; The features of the flexible soft switch SOP include uninterrupted power transfer and intelligent regulation, connecting the tail ends of two power supply areas to form a flexible interconnected distribution network with flexible closed-loop operation; The power supply restoration strategy of the flexible interconnected distribution network (FIDN) takes the weighted sum of the maximum recovery of active load of normal nodes and the minimum system operation loss as the objective function, includes multiple constraints, and establishes a stochastic optimization model for the power supply restoration of the flexible interconnected distribution network (FIDN). The power supply restoration strategy of the flexible interconnected distribution network FIDN includes the following steps: Obtain network parameters, operating fault parameters, and distributed generation parameters of the post-disaster flexible interconnected distribution network (FIDN) to determine the location and operating status of the power outage area; Determine whether the flexible soft switch SOP switches the control mode based on the location of the power-off area; According to the fault location and distributed generation parameters, the power supply restoration topology of the flexible interconnected distribution network (FIDN) is optimized, and the constraint conditions of the node voltage amplitude under uncertainty are established by using the chance constraint method. The power restoration model is transformed into a mixed integer second-order cone programming model through nonlinear constraint conditions. The network of the flexible interconnected distribution network FIDN is reconstructed according to the optimal network topology, the power-off area and the upper power grid are connected through the tie switch, and it is determined whether the flexible soft switch SOP switches the control mode.

2. The power supply restoration strategy for a flexible interconnected distribution network according to claim 1, characterized in that: The method of obtaining network parameters, operating fault parameters and distributed power generation parameters of the post-disaster flexible interconnected distribution network FIDN and determining the location and operating status of the power outage area includes the following steps: Identify the fault point based on the grid operation status provided by the grid data acquisition and monitoring control system, and call the grid below the fault point the power outage area; Construct a distributed power generation (DG) generation model and determine whether there is a distributed power generation (DG) in the power outage area. If so, determine whether the power outage area can form an island and operate independently based on the distributed power generation (DG) generation parameters and model. If not, the power outage area cannot operate independently. Determine whether there is a node in the power-off area connected to one side of the flexible soft switch SOP.

3. The power supply restoration strategy for a flexible interconnected distribution network according to claim 2, characterized in that: The method of judging whether the flexible soft switch SOP switches the control mode according to the position of the power-off area includes the following steps: The control mode of the soft switch SOP is initialized to P / QV DC / Q mode, and construct a mathematical model of flexible soft switching SOP; The power outage area is divided into the following scenarios based on its location: The power-off area is disconnected from the upper-level power grid but can operate independently, and there are nodes in the power-off area that are connected to one side of the flexible soft switch SOP; The power-off area is disconnected from the upper-level power grid but can operate independently, and there is no node in the power-off area connected to one side of the flexible soft switch SOP; The power-off area is disconnected from the upper-level power grid and cannot operate independently, and there are nodes in the power-off area that are connected to one side of the flexible soft switch SOP; The power-off area is disconnected from the upper-level power grid and cannot operate independently, and there is no node in the power-off area connected to one side of the flexible soft switch SOP; Determine whether the control mode of the flexible soft switch SOP changes according to the scenario. If the power failure area scenario is that the power failure area is disconnected from the upper level power grid and cannot operate independently, and there is a node in the power failure area connected to one side of the flexible soft switch SOP, the control mode of the flexible soft switch SOP changes from P / QV DC / Q mode conversion to V / fV DC / Q mode, the rest of the scenes remain unchanged.

4. A power supply restoration strategy for a flexible interconnected distribution network according to claim 3, characterized in that: The power restoration model is subjected to nonlinear constraint transformation to obtain a mixed integer second-order cone programming model, which includes the following steps: The nonlinear equation of the flexible soft switch SOP operation constraint is relaxed by rotating cone to obtain the linear equation; The nonlinear formula of the power flow constraint in the flexible interconnected distribution network FIDN is relaxed by rotating cone to obtain the linear formula. The sample mean approximation method is used and Monte Carlo sampling is used to transform the nonlinear constraint conditions of the chance constraint into a linear form.

5. The power supply restoration strategy for a flexible interconnected distribution network according to claim 4, characterized in that: The network reconstruction of the flexible interconnected distribution network FIDN according to the optimal network topology includes the following steps: The optimal topology is determined based on the stochastic optimization model of power restoration in the flexible interconnected distribution network (FIDN), and the flexible interconnected distribution network (FIDN) network is reconfigured through tie switches. Search whether the node connected to the flexible soft switch SOP has a line connected to the upper-level power grid; If it exists, the soft switch SOP control mode is P / QV DC / Q mode, if it does not exist, the soft switch SOP control mode is V / fV DC / Q mode.

6. A power supply restoration system for a flexible interconnected distribution network, based on a power supply restoration strategy for a flexible interconnected distribution network according to any one of claims 1 to 5, characterized in that: include, The judgment module is used to obtain the data of the post-disaster flexible interconnected distribution network FIDN and determine whether the flexible soft switch SOP switches the control mode; A model building module is used to build a stochastic optimization model for power restoration of the flexible interconnected distribution network (FIDN) based on the objective function and constraints; The power supply restoration module is used to reconstruct the network of the flexible interconnected distribution network FIDN according to the optimal network topology, and to determine whether the flexible soft switch SOP switches the control mode to realize the power supply restoration of the flexible interconnected distribution network FIDN.

7. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the processor implements the steps of a power supply restoration strategy for a flexible interconnected distribution network as described in any one of claims 1 to 5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of a power supply restoration strategy for a flexible interconnected distribution network as described in any one of claims 1 to 5 are implemented.

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