Novel power distribution system source network load storage coordinated planning method considering fault scene

Abstract

The invention discloses a novel power distribution system source network load storage coordinated planning method considering a fault scene, and relates to the field of power distribution, and the method comprises the steps: 1, building a target function of a novel power distribution system source network load storage coordinated planning model, which comprises an investment stage and an operation stage; 2, establishing a coordination optimization model of the novel power distribution system in a normal operation scene, wherein the coordination optimization model mainly comprises mathematical models of source network load storage components; 3, establishing a novel power distribution system recovery model in the fault operation scene, wherein the model mainly comprises a plurality of fault recovery stages; 4, solving the novel power distribution system source network load storage coordination plan to obtain the optimal configuration; and 5, establishing an evaluation system to demonstrate the improvement effect of the SOP access on the operation of the distribution network, and selecting a proper planning result. According to the invention, the fault scene is innovatively incorporated into the source-network-load-storage coordinated planning, and the fault resistance level and the fault recovery capability of the novel power distribution system are improved.

Description

Technical Field

[0001] The present invention relates to a power distribution system planning, and in particular to a novel power distribution system source-grid-load-storage coordination planning method taking fault scenarios into consideration. Background Art

[0002] The coordinated operation of the source, grid, load and storage of the new distribution system can give full play to the flexibility of each component and keep the entire distribution system in a better state. First of all, on the source side, unlike the traditional distribution system, the source side of the new distribution system is mainly distributed renewable energy, mainly wind power, photovoltaic and other renewable energy. On the grid side, the traditional distribution line needs to always keep the system open-loop and radial structure operation when designing, while the use of SOP allows the two ends of the distribution system to distribute the flow more accurately, changing the operation mode of the traditional distribution grid. On the load side, the traditional distribution system adopts the source following the load, and the new distribution system integrates the load, electricity price measures and demand-side response of each node. On the energy storage side, it is mainly composed of various energy storage devices, which use energy storage to smooth the output fluctuations of distributed renewable energy and provide a certain load recovery capability under faults.

[0003] Unlike traditional distribution systems that only consider line flows and power distribution, the coordinated planning of new distribution systems needs to further integrate and coordinate various flexible resources to meet the operating conditions of the system, including the site selection and capacity determination of distributed renewable energy, grid topology, load on the load side, and coordination of SOP and RCS. Many experts and scholars have conducted relevant research on the site selection and capacity determination of distributed renewable energy in distribution networks and the planning of soft switches, but few have focused on the coordinated planning of new distribution systems to improve system resilience. There are many uncertainties in the actual operation of distribution systems, which are easily affected by extreme weather and natural disasters. Therefore, it is very necessary to study the coordinated planning of source, grid, load and storage for new distribution systems that consider fault scenarios to improve the economy of system planning and fault recovery capabilities. Summary of the invention

[0004] The purpose of the present invention is to provide a new distribution system source-grid-load-storage coordinated planning method taking into account fault scenarios, which can significantly improve the economy and fault recovery capability of system planning to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A new distribution system source-grid-load-storage coordinated planning method considering fault scenarios, step 1: establishing the objective function of the new distribution system source-grid-load-storage coordinated planning model.

[0007] Detailed process: The objective function is shown in formula (1a), which consists of two parts: investment cost and operating cost:

[0008]

[0009]

[0010]

[0011]

[0012] In formula (1a): obj is the objective function to be optimized, C inv , C op , C f are the investment cost, operation cost and load loss cost of the distribution network under fault scenarios, r and x are the annual investment interest rate and investment period, respectively. Represents the unit investment cost of wind power, photovoltaic power, energy storage battery, soft switch, line length and SVG respectively. Represents the expansion cost, new construction cost and RCS installation cost of the substation; Ω wt ,Ω pv ,Ω es ,Ω sop ,Ω svg ,Ω L ,Ω sub ,Ω esub ,Ω RCS Represents the construction lines and nodes of wind power, photovoltaic power, energy storage battery, soft switch, SVG, line, new substation, expandable substation and RCS respectively; WT i PV i ,ES i SVG i , Respectively represent the installed capacity of wind power, photovoltaic power, energy storage, and SVG at the i-th node, and whether to expand or build a new substation at the node; SOP ij , l ij 、x ij , are binary variables representing the capacity of SOP installed on line ij, the length of the line, whether line ij is built, and whether RCS is installed. In formula (1c): S is the number of normal scenarios, ρ s is the probability of the corresponding scene occurring; are the power of wind and solar power abandonment, battery discharge, battery charging, substation power purchase and load shedding at node i at time t under scenario s; are the annual maintenance costs of wind power, photovoltaic power and SOP under unit capacity respectively; f wt 、f pv 、f n , are the unit wind curtailment, solar curtailment, load shedding and battery degradation costs respectively; p t and is the electricity price of the substation at time t and the annual maintenance cost of each line. In formula (1d): S f is the number of failure scenarios, ρ sf is the probability of the corresponding failure scenario, T R is the maximum fault recovery time after a fault occurs; and are the load loss penalty cost of the corresponding faulty node and the load lost by node i due to the fault at time t, respectively.

[0013] Step 2: Establish a “source-grid-load-storage” optimization mathematical model including SOP under normal scenarios.

[0014] First, the source side is modeled. In this invention, wind power and photovoltaic power are considered as distributed power sources connected to the distribution network, and SOP is used as a regulating power electronic device to balance the power flow distribution level in the distribution system. In order to better balance the reactive power and voltage distribution level in the system, SVG is also considered as a reactive power regulation device. The output characteristics of wind power and photovoltaic power are shown in equations (2a) and (2b):

[0015]

[0016]

[0017] In formula (2a), v ay 、v cin 、v rate 、v cof They are respectively the wind turbine’s current operating wind speed, cut-in wind speed, rated wind speed, and cut-out wind speed. is the rated power of the wind turbine. In formula (2b), sc is the current light intensity, SC rate is the light intensity when the photovoltaic module reaches the rated power, is the rated power of the PV module.

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024] Formula (2c) (2d) represents the maximum capacity of the corresponding distributed power source that can be installed at the node, where They are binary variables indicating whether wind power and photovoltaic power are installed at the node; are the maximum allowed wind power and photovoltaic capacity installed at the node. (2e)-(2f) are the power balance constraints of wind and photovoltaic output, where is the actual wind power and photovoltaic power consumption at time t under scenario s, the abandoned wind and photovoltaic power, and the unit output of wind power and photovoltaic power at the current time. (2g)(2h) is the maximum wind and photovoltaic abandonment constraint, where λ PV and λ WT is the maximum allowable wind and solar power abandonment rate of the system.

[0025] SVG is a reactive power compensation device that can achieve continuous regulation of reactive power, optimize voltage distribution in the distribution system and power transmission level in the line.

[0026]

[0027]

[0028] Formula (2i) is the installation capacity and location constraints of SVG, is a binary variable indicating whether SVG is installed at node i. is the maximum allowed installed SVG capacity at node i; Formula (2j) is the output power constraint of SVG, is the reactive power output of node i at time t in scenario s, β min and β max They are the down-scaling factor and up-scaling factor of SVG output respectively.

[0029] In addition to using distributed power sources, the power distribution system also needs to obtain power from the main grid to compensate for the intermittent output of distributed renewable energy and adjust the peak-to-valley difference of the power distribution system. The present invention considers the construction and expansion of substations to meet the operation of the power distribution system.

[0030]

[0031]

[0032] Formulas (2k)-(2l) are the capacity constraints of the substation. Reactive power provided to the substation, K sub is the maximum load of the substation, They are the newly built rated capacity of the substation at node i, the initial capacity of the substation and the expandable rated capacity of the substation.

[0033] Figure 2.1 is the physical structure diagram of the flexible soft switch. SOP, as a back-to-back power electronic device, consists of two converters, VSC1 and VSC2. A capacitor is connected in parallel between the two converters to provide reactive power to the nodes at both ends of the feeder.

[0034]

[0035]

[0036]

[0037]

[0038]

[0039] Formula (2m)-(2q) is the mathematical model of SOP during operation. They are respectively the active power, reactive power, active power loss, capacity and loss coefficient of the converter at node i connected to the soft switch in scenario s at time t. Formula (2m) is the power balance constraint inside the SOP; (2n) and (2o) are the active power losses at both ends of the SOP; (2p)-(2q) are the capacity constraints of the converter equipment at the SOP access point.

[0040] Next is the modeling of the grid-side model. The distribution network needs to always maintain radial operation. The network topology constraints of newly built substations and newly added load nodes are as follows:

[0041]

[0042]

[0043]

[0044]

[0045] |y ij |≤(nn s0 )x ij ,(i,j)∈Ω L (3e)

[0046] In formula (3a), N is the number of newly added load nodes. This constraint means that the number of newly added load nodes must be equal to the number of newly added lines to ensure that the lines are radial. However, this constraint alone cannot satisfy the requirement that the distribution network containing distributed power sources maintains radial operation. The access of distributed power sources will cause node island operation and even lead to the emergence of a ring network. Therefore, constraints (3b)-(3e) are required for further restrictions. In constraint (3b), y ij is the virtual power flow from node i to node j, n is the number of nodes in the line, ns0 is the number of existing substations in the network. This constraint limits the maximum virtual power flow that can be generated by the existing substation nodes. Constraint (3c) indicates that when the node is a newly built substation node, the constraint degenerates to the substation node shown in (3b). When the substation node is not built, the constraint degenerates to the virtual load node in (3d). Constraint (3d) indicates that when the node is a load node, the sum of the virtual power flows passing through the node is -1, that is, it is a virtual load. Constraint (3e) indicates that when the line is put into construction, the virtual power flow can be transmitted on the line, otherwise it cannot be transmitted.

[0047] When power is transmitted in the distribution network, it is necessary to meet relevant power flow constraints. In this invention, a linearized DistFlow power flow model is adopted, and the non-convex terms of network loss are ignored to simplify the complexity of the final model calculation. At present, existing literature has confirmed that in the planning of the distribution network, the final result is less affected by the factors of network loss, and the influence of network loss on the planning result can be ignored.

[0048]

[0049]

[0050]

[0051]

[0052] U min ≤U i,t,s ≤U max i∈Ω n (3j)

[0053]

[0054] Formula (3f) and Formula (3g) are the active and reactive power balance constraints of the node. P ij,t,s , Q ij,t,s are respectively the active and reactive power injected into node i at time t in scenario s, the active load and reactive load of the node, and the active and reactive power transmitted from node i to node j. Equations (3h)-(3i) are the DistFlow power flow models after linearization with network loss ignored, where U i,t,s ,M, V0 is the voltage of node i at time t in scenario s, a sufficiently large positive number, the impedance and inductance of the line between nodes ij, and the calibrated voltage of the distribution system. Formula (3j) is a safety constraint to ensure that the voltage of each node is within the allowable range, where U min and U max is the upper and lower voltage limits allowed by the node. Formula (3k) is the capacity constraint of the line, where S ijis the maximum capacity of the transmission line.

[0055] On the load side, the excessive load response is considered to be reduced under the condition of demand-side response, where the load reduction amount is related to the load level, as shown in equation (3l). Equations (3m)-(3n) are the active and reactive power injected into each node in the distribution system.

[0056]

[0057]

[0058]

[0059] In formula (31), ξ i is the maximum load reduction ratio at node i, and its value is related to the load level. is the active power reduced by node i at time t in scenario s. Equations (3m)-(3n) are the active and reactive powers injected into the node, where is the power of the electric vehicle battery swap station at node i at time t in scenario s.

[0060] Finally, there are the constraints on the location and capacity of energy storage and electric vehicle swap stations. The mathematical model of the electric vehicle swap station is similar to that of energy storage, and can be regarded as an energy storage device that can only be charged. Equations (4a)-(4f) are the charging and discharging constraints of energy storage batteries:

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067] Formula (4a) is the installation constraint of the energy storage battery. and is a binary variable indicating whether energy storage is installed at node i and the maximum energy storage installation capacity allowed at the node. Equations (4b)-(4d) are the operating state constraints of the energy storage battery, where is a binary variable representing the battery charging and discharging status; k ch , k dis is the charge and discharge depth of the energy storage battery. Equations (4e)-(4f) are the capacity constraints of the energy storage battery charge and discharge. ηch , η ch is the amount of electricity stored in the energy storage battery at node i at time t in scenario s, and the battery charging and discharging efficiency.

[0068] The site selection of electric vehicle battery swap stations is similar to the planning of energy storage batteries. There are generally several nodes to be selected for the site selection of electric vehicle battery swap stations. The specific site selection constraints are as follows:

[0069]

[0070]

[0071] Formula (4g) is the location constraint of electric vehicles. represents the location set of the i-th electric vehicle swap station, is a binary variable for whether to select a site for construction; Ω ev is the set of battery swap stations to be sited. Formula (4h) is the power constraint on the node after the battery swap station is sited.

[0072] Step 3: Establish a new distribution system recovery model under fault operation scenarios.

[0073] Detailed process: Since the power distribution system is an integrated whole, a line fault will directly affect the normal operation of other components of the power distribution system. When a power distribution system fault occurs, the remote control switch (RCS) can isolate the fault and prevent the fault from spreading, so as to ensure the normal operation of most nodes in the power distribution system.

[0074] The first is the isolation phase after the fault occurs. When a fault occurs in the distribution system, the RCS can isolate the fault on the line and prevent the further spread of the accident. In the isolation phase, constraints (5a)-(5d) are satisfied.

[0075]

[0076]

[0077]

[0078]

[0079] 0≤a ij ≤x ij (i,j)∈Ω L (5e)

[0080] Formula (5a) represents the line fault constraint, f ij,s 1 indicates that line ij fails in the sth scenario; a ij It is a binary variable for installing RCS. 1 means that line ij has installed RCS. is the connection status of line ij after the fault occurs, T f is the time period during which the fault occurs. Equations (5b)-(5d) are fault isolation diffusion constraints, where Indicates that node i is in scene s T f The state variable of whether there is a fault at the moment, these four constraints can simulate the fault diffusion process of the distribution system and the blocking state of RCS to the fault. Formula (5e) shows that RCS can only be installed on the line, and RCS cannot be installed on the line without planning.

[0081] In the fault scenario, the node failure will directly affect the normal operation of distributed power supply, energy storage, SOP and other power electronic equipment. After the fault occurs, it is necessary to cut it out from the fault location to protect the safety of the equipment. The specific constraint model after the fault is shown in equations (5f)-(5n):

[0082]

[0083]

[0084]

[0085]

[0086]

[0087]

[0088]

[0089]

[0090]

[0091] Formulas (5f)-(5n) are the output constraints of wind turbines, photovoltaic units, battery energy storage, SVG, SOP, new substations, and expanded substations under fault scenarios. After a fault occurs, the system needs to cut off a certain amount of load to ensure the normal operation of the remaining systems. In the fault scenario, the load loss must meet constraints (5o)-(5p):

[0092]

[0093]

[0094] When a distribution system fails, the post-fault recovery process must be considered to determine the maximum power supply recovery plan for the distribution system. When the corresponding line is repaired, the node fault is cleared. During the repair process, constraints (5q)-(5v) are satisfied:

[0095]

[0096]

[0097] n i,t,s ≥n i,t+1,s i∈Ω n (5s)

[0098]

[0099]

[0100]

[0101] Formula (5q) represents the constraint on the maximum number of lines restored per hour, where R is the maximum number of lines that can be restored per hour; Formula (5r) is the line repair constraint, T re is the period of complete fault repair, indicating that all faulty lines must be repaired within a specified time after the fault occurs; Formulas (5s)-(5t) are fault recovery constraints. During the line repair process, the faults of the nodes at both ends of the faulty line are cleared when the line is repaired, where Ω F is the set where the faulty line is located; formulas (5u)-(5v) ensure that the fault states of the two ends of the same line are the same without installing RCS during the fault recovery process. After installing RCS, if a fault occurs at one end of the line, it can be isolated.

[0102] Step 4: Solve the source-grid-load-storage coordination planning of the new distribution system.

[0103] Specific process: The objective function in step 1 and the constraints in the normal operation scenario and the fault operation scenario in steps 2-3 are modeled in MATLAB using YALMIP, and solved using the commercial solver Cplex.

[0104] Step 5: Establish an evaluation system to demonstrate the role of SOP access in improving distribution network operation.

[0105] Specific process: After obtaining the optimal configuration capacity of the system, calculate the values ​​of various indicators of the system with and without SOP access, and compare the indicators to prove that the system can achieve better performance with SOP access.

[0106]

[0107]

[0108]

[0109]

[0110]

[0111] In formula (6a), L mean is the maximum average load level of the line channel; V in formula (6b) mean is the maximum average voltage deviation level of the system during operation, where V norm is the system's nominal voltage; in formula (6c) represents the maximum load loss ratio in all scenarios after a system failure; in formula (6d) It represents the average time required for load recovery under all fault scenarios. is the time for the load to be fully restored under fault scenario s. Formula (6e) represents the average recovery rate of the system load at a single moment under fault scenario.

[0112] Compared with the prior art, the beneficial effects of the present invention are: (1) the fault scenarios are innovatively incorporated into the coordinated planning of source, grid, load and storage, thereby improving the fault resistance level and fault recovery capability of the new distribution system; (2) multiple links of the new distribution system including source, grid, load and storage, including SOP and RCS, are jointly planned, and a reasonable evaluation system is established, which can achieve a better balance between the economy and fault recovery capability of the distribution network, and has good engineering application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0113] Figure 1 Schematic diagram of the flow chart of the new distribution system source-grid-load-storage coordination planning method considering fault scenarios.

[0114] Figure 2 Schematic diagram of the electrical structure of the flexible soft switch physical structure in the new distribution system source-grid-load-storage coordinated planning method considering fault scenarios.

[0115] Figure 3 This is the Portugal54 node network topology diagram in the implementation example of the new distribution system source-grid-load-storage coordination planning method considering fault scenarios.

[0116] Figure 4 This is a "source-grid-load-storage" planning result diagram containing SOP in the implementation example of the source-grid-load-storage coordinated planning method for a new distribution system considering fault scenarios.

[0117] Figure 5 This is a distribution network planning result diagram without SOP access in the implementation example of the source-grid-load-storage coordinated planning method for a new distribution system considering fault scenarios. DETAILED DESCRIPTION

[0118] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0119] See also Figure 1 In an embodiment of the present invention, a new distribution system source-grid-load-storage coordinated planning method considering fault scenarios, step 1: establishing an objective function of a new distribution system source-grid-load-storage coordinated planning model.

[0120] Detailed process: The investment planning objective function based on the distribution network is shown in formula (1a), which consists of two parts: investment cost and operating cost:

[0121]

[0122]

[0123]

[0124]

[0125] In formula (1a): obj is the objective function to be optimized, C inv , C op , C f are the investment cost, operation cost and load loss cost of the distribution network under fault scenarios, r and x are the annual investment interest rate and investment period, respectively. Represents the unit investment cost of wind power, photovoltaic power, energy storage battery, soft switch, line length and SVG respectively. Represents the expansion cost, new construction cost and RCS installation cost of the substation; Ω wt ,Ω pv ,Ω es ,Ω sop ,Ω svg ,Ω L ,Ω sub ,Ω esub ,Ω RCS Represents the construction lines and nodes of wind power, photovoltaic power, energy storage battery, soft switch, SVG, line, new substation, expandable substation and RCS respectively; WT i PV i ,ES i SVG i , Respectively represent the installed capacity of wind power, photovoltaic power, energy storage, and SVG at the i-th node, and whether to expand or build a new substation at the node; SOP ij , l ij 、x ij , are binary variables representing the capacity of SOP installed on line ij, the length of the line, whether line ij is built, and whether RCS is installed. In formula (1c): S is the number of normal scenarios, ρ s is the probability of the corresponding scene occurring; are the power of wind and solar power abandonment, battery discharge, battery charging, substation power purchase and load shedding at node i at time t under scenario s; are the annual maintenance costs of wind power, photovoltaic power and SOP under unit capacity respectively; f wt 、f pv 、f n , are the unit wind curtailment, solar curtailment, load shedding and battery degradation costs respectively; p t and is the electricity price of the substation at time t and the annual maintenance cost of each line. In formula (1d): S f is the number of failure scenarios, ρ sf is the probability of the corresponding failure scenario, T R is the maximum fault recovery time after a fault occurs; and are the load loss penalty cost of the corresponding faulty node and the load lost by node i due to the fault at time t, respectively.

[0126] Step 2: Establish a coordinated optimization model for the new distribution system under normal operation scenarios.

[0127] First, the source side is modeled. In this invention, wind power and photovoltaic power are considered as distributed power sources connected to the distribution network, and SOP is used as a regulating power electronic device to balance the power flow distribution level in the distribution system. In order to better balance the reactive power and voltage distribution level in the system, SVG is also considered as a reactive power regulation device. The output characteristics of wind power and photovoltaic power are shown in equations (2a) and (2b):

[0128]

[0129]

[0130] In formula (2a), v ay 、v cin 、v rate 、v cof They are respectively the wind turbine’s current operating wind speed, cut-in wind speed, rated wind speed, and cut-out wind speed. is the rated power of the wind turbine. In formula (2b), sc is the current light intensity, SC rate is the light intensity when the photovoltaic module reaches the rated power, is the rated power of the PV module.

[0131]

[0132]

[0133]

[0134]

[0135]

[0136]

[0137] Formula (2c) (2d) represents the maximum capacity of the corresponding distributed power source that can be installed at the node, where They are binary variables indicating whether wind power and photovoltaic power are installed at the node; are the maximum allowed wind power and photovoltaic capacity installed at the node. (2e)-(2f) are the power balance constraints of wind and photovoltaic output, where is the actual wind power and photovoltaic power consumption at time t under scenario s, the abandoned wind and photovoltaic power, and the unit output of wind power and photovoltaic power at the current time. (2g)(2h) is the maximum wind and photovoltaic abandonment constraint, where λ PV and λ WT is the maximum allowable wind and solar power abandonment rate of the system.

[0138] SVG is a reactive power compensation device that can achieve continuous regulation of reactive power, optimize voltage distribution in the distribution system and power transmission level in the line.

[0139]

[0140]

[0141] Formula (2i) is the installation capacity and location constraints of SVG, is a binary variable indicating whether SVG is installed at node i. is the maximum allowed installed SVG capacity at node i; Formula (2j) is the output power constraint of SVG, is the reactive power output of node i at time t in scenario s, β min and β max They are the down-scaling factor and up-scaling factor of SVG output respectively.

[0142] In addition to using distributed power sources, the power distribution system also needs to obtain power from the main grid to compensate for the intermittent output of distributed renewable energy and adjust the peak-to-valley difference of the power distribution system. The present invention considers the construction and expansion of substations to meet the operation of the power distribution system.

[0143]

[0144]

[0145] Formulas (2k)-(2l) are the capacity constraints of the substation. Reactive power provided to the substation, K sub is the maximum load of the substation, They are the newly built rated capacity of the substation at node i, the initial capacity of the substation and the expandable rated capacity of the substation.

[0146] Figure 2 The physical structure diagram of the flexible soft switch. SOP is a back-to-back power electronic device composed of two converters, VSC1 and VSC2. A capacitor is connected in parallel between the two converters to provide reactive power to the nodes at both ends of the feeder.

[0147]

[0148]

[0149]

[0150]

[0151]

[0152] Formula (2m)-(2q) is the mathematical model of SOP during operation. They are respectively the active power, reactive power, active power loss, capacity and loss coefficient of the converter at node i connected to the soft switch in scenario s at time t. Formula (2m) is the power balance constraint inside the SOP; (2n) and (2o) are the active power losses at both ends of the SOP; (2p)-(2q) are the capacity constraints of the converter equipment at the SOP access point.

[0153] Next is the modeling of the grid-side model. The distribution network needs to always maintain radial operation. The network topology constraints of newly built substations and newly added load nodes are as follows:

[0154]

[0155]

[0156]

[0157]

[0158] |y ij |≤(nn s0 )x ij ,(i,j)∈Ω L (3e)

[0159] In formula (3a), N is the number of newly added load nodes. This constraint means that the number of newly added load nodes must be equal to the number of newly added lines to ensure that the lines are radial. However, this constraint alone cannot satisfy the requirement that the distribution network containing distributed power sources maintains radial operation. The access of distributed power sources will cause node island operation and even lead to the emergence of a ring network. Therefore, constraints (3b)-(3e) are required for further restrictions. In constraint (3b), y ij is the virtual power flow from node i to node j, n is the number of nodes in the line, n s0 is the number of existing substations in the network. This constraint limits the maximum virtual power flow that can be generated by the existing substation nodes. Constraint (3c) indicates that when the node is a newly built substation node, the constraint degenerates to the substation node shown in (3b). When the substation node is not built, the constraint degenerates to the virtual load node in (3d). Constraint (3d) indicates that when the node is a load node, the sum of the virtual power flows passing through the node is -1, that is, it is a virtual load. Constraint (3e) indicates that when the line is put into construction, the virtual power flow can be transmitted on the line, otherwise it cannot be transmitted.

[0160] When power is transmitted in the distribution network, it is necessary to meet relevant power flow constraints. In this invention, a linearized DistFlow power flow model is adopted, and the non-convex terms of network loss are ignored to simplify the complexity of the final model calculation. At present, existing literature has confirmed that in the planning of the distribution network, the final result is less affected by the factors of network loss, and the influence of network loss on the planning result can be ignored.

[0161]

[0162]

[0163]

[0164]

[0165] U min ≤U i,t,s ≤U max i∈Ω n (3j)

[0166]

[0167] Formula (3f) and Formula (3g) are the active and reactive power balance constraints of the node. P ij,t,s , Q ij,t,s are respectively the active and reactive power injected into node i at time t in scenario s, the active load and reactive load of the node, and the active and reactive power transmitted from node i to node j. Equations (3h)-(3i) are the DistFlow power flow models after linearization with network loss ignored, where U i,t,s ,M, V0 is the voltage of node i at time t in scenario s, a sufficiently large positive number, the impedance and inductance of the line between nodes ij, and the calibrated voltage of the distribution system. Formula (3j) is a safety constraint to ensure that the voltage of each node is within the allowable range, where U min and U max is the upper and lower voltage limits allowed by the node. Formula (3k) is the capacity constraint of the line, where S ij is the maximum capacity of the transmission line.

[0168] On the load side, the excessive load response is considered to be reduced under the condition of demand-side response, where the load reduction amount is related to the load level, as shown in equation (3l). Equations (3m)-(3n) are the active and reactive power injected into each node in the distribution system.

[0169]

[0170]

[0171]

[0172] In formula (31), ξ i is the maximum load reduction ratio at node i, and its value is related to the load level. is the active power reduced by node i at time t in scenario s. Equations (3m)-(3n) are the active and reactive powers injected into the node, where is the power of the electric vehicle battery swap station at node i at time t in scenario s.

[0173] Finally, there are the constraints on the location and capacity of energy storage and electric vehicle swap stations. The mathematical model of the electric vehicle swap station is similar to that of energy storage, and can be regarded as an energy storage device that can only be charged. Equations (4a)-(4f) are the charging and discharging constraints of energy storage batteries:

[0174]

[0175]

[0176]

[0177]

[0178]

[0179]

[0180] Formula (4a) is the installation constraint of the energy storage battery. and is a binary variable indicating whether energy storage is installed at node i and the maximum energy storage installation capacity allowed at the node. Equations (4b)-(4d) are the operating state constraints of the energy storage battery, where is a binary variable representing the battery charging and discharging status; k ch , k dis is the charge and discharge depth of the energy storage battery. Equations (4e)-(4f) are the capacity constraints of the energy storage battery charge and discharge. η ch , η ch is the amount of electricity stored in the energy storage battery at node i at time t in scenario s, and the battery charging and discharging efficiency.

[0181] The site selection of electric vehicle battery swap stations is similar to the planning of energy storage batteries. There are generally several nodes to be selected for the site selection of electric vehicle battery swap stations. The specific site selection constraints are as follows:

[0182]

[0183]

[0184] Formula (4g) is the location constraint of electric vehicles. represents the location set of the i-th electric vehicle swap station, is a binary variable for whether to select a site for construction; Ω ev is the set of battery swap stations to be sited. Formula (4h) is the power constraint on the node after the battery swap station is sited.

[0185] Step 3: Establish a new distribution system recovery model under fault operation scenarios.

[0186] Detailed process: Since the power distribution system is an integrated whole, a line fault will directly affect the normal operation of other components of the power distribution system. When a power distribution system fault occurs, the remote control switch (RCS) can isolate the fault and prevent the fault from spreading, so as to ensure the normal operation of most nodes in the power distribution system.

[0187] The first is the isolation phase after the fault occurs. When a fault occurs in the distribution system, the RCS can isolate the fault on the line and prevent the further spread of the accident. In the isolation phase, constraints (5a)-(5d) are satisfied.

[0188]

[0189]

[0190]

[0191]

[0192] 0≤a ij ≤x ij (i,j)∈Ω L (5e)

[0193] Formula (5a) represents the line fault constraint, f ij,s 1 means that line ij=failed in the sth scenario; a ij It is a binary variable for installing RCS. 1 means that line ij has installed RCS. is the connection status of line ij after the fault occurs, T f is the time period during which the fault occurs. Equations (5b)-(5d) are fault isolation diffusion constraints, where n i,Tf,s Indicates that node i is in scene s T f The state variable of whether there is a fault at the moment, these four constraints can simulate the fault diffusion process of the distribution system and the blocking state of RCS to the fault. Formula (5e) shows that RCS can only be installed on the line, and RCS cannot be installed on the line without planning.

[0194] In the fault scenario, the node failure will directly affect the normal operation of distributed power supply, energy storage, SOP and other power electronic equipment. After the fault occurs, it is necessary to cut it out from the fault location to protect the safety of the equipment. The specific constraint model after the fault is shown in equations (5f)-(5n):

[0195]

[0196]

[0197]

[0198]

[0199]

[0200]

[0201]

[0202]

[0203]

[0204] Formulas (5f)-(5n) are the output constraints of wind turbines, photovoltaic units, battery energy storage, SVG, SOP, new substations, and expanded substations under fault scenarios. After a fault occurs, the system needs to cut off a certain amount of load to ensure the normal operation of the remaining systems. In the fault scenario, the load loss must meet constraints (5o)-(5p):

[0205]

[0206]

[0207] When a distribution system fails, the post-fault recovery process must be considered to determine the maximum power supply recovery plan for the distribution system. When the corresponding line is repaired, the node fault is cleared. During the repair process, constraints (5q)-(5v) are satisfied:

[0208]

[0209]

[0210] n i,t,s ≥n i,t+1,s i∈Ω n (5s)

[0211]

[0212]

[0213]

[0214] Formula (5q) represents the constraint on the maximum number of lines restored per hour, where R is the maximum number of lines that can be restored per hour; Formula (5r) is the line repair constraint, T re is the period of complete fault repair, indicating that all faulty lines must be repaired within a specified time after the fault occurs; Formulas (5s)-(5t) are fault recovery constraints. During the line repair process, the faults of the nodes at both ends of the faulty line are cleared when the line is repaired, where Ω F is the set where the faulty line is located; formulas (5u)-(5v) ensure that the fault states of the two ends of the same line are the same without installing RCS during the fault recovery process. After installing RCS, if a fault occurs at one end of the line, it can be isolated.

[0215] Step 4: Solve the source-grid-load-storage coordination planning of the new distribution system.

[0216] Specific process: The objective function in step 1 and the constraints in the normal operation scenario and the fault operation scenario in steps 2-3 are modeled in MATLAB using YALMIP, and solved using the commercial solver Cplex.

[0217] Step 5: Establish an evaluation system to demonstrate the role of SOP access in improving distribution network operation.

[0218] Specific process: After obtaining the optimal configuration capacity of the system, calculate the values ​​of various indicators of the system with and without SOP access, and compare the indicators to prove that the system can achieve better performance with SOP access.

[0219]

[0220]

[0221]

[0222]

[0223]

[0224] In formula (6a), L mean is the maximum average load level of the line channel; V mean is the maximum average voltage deviation level of the system during operation, where V norm is the system's nominal voltage; in formula (6c) represents the maximum load loss ratio in all scenarios after a system failure; in formula (6d) It represents the average time required for load recovery under all fault scenarios. is the time for the load to be fully restored under fault scenario s. Formula (6e) represents the average recovery rate of the system load at a single moment under fault scenario.

[0225] Simulation Case Study

[0226] The present invention uses the Portugal 54-node system to verify the solution. Nodes S1 and S2 are existing substation nodes in the system, with an initial capacity of 16.7MVA and expandable capacities of 16.7MVA and 13.3MVA respectively; nodes S3 and S4 are substation nodes to be built, with a construction capacity of 22.2MVA. The voltage level of the distribution system is 15KV, and the total active load is 71.6MW. The topology of the system is as follows: Figure 3 shown.

[0227] The wind power construction nodes in the system are 13, 16, 22, 24, and 47, the photovoltaic construction nodes are 5, 10, 30, 42, and 47, the energy storage construction nodes are 17, 31, 35, and 45, the SVG construction nodes are 20, 32, 43, and 49, and the SOP construction lines are 2-8, 6-28, 10-15, 30-43, 33-39, 46-47, and 22-23. The optional access points for electric vehicle swap stations are (37, 43, 45), (9, 22, 23), (8, 33, 34), and (40, 48, and 50). The power purchase price of the upper substation of the substation is 0.834, 0.648, and 0.371￥ / KW during peak, normal, and valley hours. The total investment period of the system is 20 years, the discount rate is 5%, the penalty cost for wind and solar abandonment is 0.4￥ / KW, the demand side response cost is 10￥ / KW, the charging and discharging efficiency of the energy storage battery is 0.9, the charging and discharging depth is 20%, the maximum capacity of the line is 12MVA, the voltage allowable range is 0.95-1.05pu, and the maximum number of lines restored per hour in the system is 2. In the present invention, the load level of 54 nodes is calibrated as shown in Table 9-5:

[0228] Table 9-5 54-node load levels and parameters

[0229]

[0230] 1. Analysis of planning results:

[0231] Figure 4 This is the result of the distribution network planning with SOP access. The planned line topology, whether the substation is newly built or expanded, and the location of the electric vehicle swap station are all marked in the figure. The installed capacity of distributed power sources, energy storage, SVG, and SOP is shown in Table 9-7:

[0232] Table 9-7 Capacity results of “source-grid-load-storage” planning including SOP

[0233]

[0234] Figure 5 This is the planning result of the distribution network without SOP access. The configured network topology and other information are already included in the figure. The specific configuration capacity and parameters are shown in Table 9-8:

[0235] Table 9-8 Capacity results of “source-grid-load-storage” planning without SOP

[0236]

[0237] Table 9-9 shows the expansion costs of various aspects and their comparison results under the two planning methods:

[0238] Table 9-9 Cost comparison results between different solutions

[0239]

[0240] From the overall planning results, the investment cost of the distribution network planning method with SOP and the planning method without SOP is similar, but there is a big difference in operating cost. From the perspective of system investment, the installed capacity of wind power and photovoltaic power is roughly the same between the two methods, and the gap is not obvious, but there is a big difference in the installed capacity of SVG and ESS. The reason for the large difference in SVG capacity is that the SOP access system can provide a certain amount of reactive power to the end nodes of the system, reducing the dependence of the end nodes on the reactive power of the substation, thereby optimizing the power distribution of the line, and then reducing the dependence of the distribution system on SVG; the large difference in ESS capacity is that the distribution network with SOP can transfer and compensate active power from unconnected systems. Compared with a single distribution network structure, it has stronger power regulation capabilities and less dependence on energy storage.

[0241] Judging from the system operation results, the planning method with SOP is significantly better than the planning without SOP in terms of substation power purchase cost, demand response cost, and wind and solar power abandonment cost. It can be seen that with the access of SOP, the distribution network's acceptance capacity for new energy is significantly better than that without SOP access. The demand side response cost in the planning method without considering SOP access is much higher than the cost with SOP access, indicating that SOP can optimize the power distribution level in the distribution network, thereby reducing unnecessary load shedding in the distribution network. However, the average annual failure cost of the planning method with SOP is higher than that without SOP, and the planning method without SOP is more inclined to deploy more RCS. This is because the distribution network without SOP is more dependent on energy storage and distributed power sources in fault recovery, and more RCS needs to be deployed to isolate the fault after the fault occurs to maximize power supply. Compared with the probability of normal scenarios, the probability of extreme fault scenarios is very small. The distribution network without SOP is more inclined to deploy more energy storage batteries to optimize the cost under normal scenarios. When the fault is restored, the distribution network without SOP can make full use of distributed power sources and large-capacity energy storage equipment to restore the fault power supply and reduce the fault loss, but it also invisibly increases the demand for energy storage in the distribution network. The evaluation indicators introduced show that all aspects of the system indicators have been improved after the SOP is connected, which can well improve the operation level of the distribution network.

[0242] In summary, the present invention:

[0243] (1) Innovatively incorporating fault scenarios into the coordinated planning of sources, grids, loads and storage, improving the fault resistance and fault recovery capabilities of the new distribution system;

[0244] (2) Joint planning of multiple links of the new distribution system including SOP and RCS, including source, grid, load and storage, and establishment of a reasonable evaluation system can achieve a better balance between the economy and fault recovery capability of the distribution network, which has good engineering application prospects.

[0245] Explanation of relevant terms involved in the present invention:

[0246] "Source-Grid-Load-Storage": "Source-Grid-Load-Storage" are functional components in the distribution system, representing distributed power sources, grid topology, load-side demand response, and energy storage equipment respectively.

[0247] Flexible Soft Switch (SOP): A flexible soft switch is a back-to-back power electronic device with high flexibility, strong power flow transfer and reactive voltage support capabilities, and can assist in fault repair after a fault occurs.

[0248] Coordination planning: Coordination planning refers to the site selection and capacity determination of each component in the distribution system so that the systems can coordinate and cooperate with each other to achieve the best overall external performance of the system.

[0249] New distribution system: Compared with the traditional distribution system, the new distribution system is connected to a large number of distributed renewable energy, SOP, distributed energy storage and flexible loads.

[0250] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0251] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A new distribution system source-grid-load-storage coordination planning method considering fault scenarios, characterized in that: The steps include: Step 1: Construction of the objective function of source-grid-load-storage coordination planning for the new distribution system: The objective function is shown in formula (1a), which consists of two parts: investment cost and operating cost. composition: In formula (1a): obj is the objective function to be optimized, C inv , C op , C f are the investment cost, operation cost and load loss cost of the distribution network under fault scenarios, r and x are the annual investment interest rate and investment period, respectively. In formula (1b) Represents the unit investment cost of wind power, photovoltaic power, energy storage battery, soft switch, line length and SVG respectively. Represents the expansion cost, new construction cost and RCS installation cost of the substation; Ω wt ,Ω pv ,Ω es ,Ω sop ,Ω svg ,Ω L ,Ω sub ,Ω esub ,Ω RCS Represents the construction lines and nodes of wind power, photovoltaic power, energy storage battery, soft switch, SVG, line, new substation, expandable substation and RCS respectively; WT i PV i ,ES i SVG i , Respectively represent the installed capacity of wind power, photovoltaic power, energy storage, and SVG at the i-th node, and whether a substation is expanded or newly built at the node; SOP ij , l ij 、x ij , are binary variables representing the capacity of SOP installed on line ij, the length of the line, whether line ij is built, and whether RCS is installed. In formula (1c), S is the number of normal scenarios, ρ s is the probability of the corresponding scene occurring; are the power of wind and solar power abandonment, battery discharge, battery charging, substation power purchase and load shedding at node i at time t under scenario s; are the annual maintenance costs of wind power, photovoltaic power and SOP under unit capacity respectively; f wt 、f pv 、f n , are the unit wind curtailment, solar curtailment, load shedding and battery degradation costs respectively; p t and is the electricity price of the substation at time t and the annual maintenance cost of each line. In formula (1d): S f is the number of failure scenarios, ρ sf is the probability of the corresponding failure scenario, T R is the maximum fault recovery time after a fault occurs; and are the load loss penalty cost of the corresponding faulty node and the load loss of node i due to the fault at time t, Step 2: Establish a coordinated optimization model for the new distribution system under normal operation scenarios: First, the source side is modeled. The output characteristics of wind power and photovoltaic power are shown in equations (2a) and (2b): In formula (2a), v ay 、v cin 、v rate 、v cof They are respectively the wind turbine’s current operating wind speed, cut-in wind speed, rated wind speed, and cut-out wind speed. is the rated power of the wind turbine, in formula (2b), sc is the current light intensity, SC rate is the light intensity when the photovoltaic module reaches the rated power, is the rated power of the PV module, Formula (2c) (2d) represents the maximum capacity of the corresponding distributed power source that can be installed at the node, where They are binary variables indicating whether wind power and photovoltaic power are installed at the node; are the maximum allowed installed wind power and photovoltaic capacity at the node, (2e)-(2f) are the power balance constraints of wind and solar power output, where is the actual wind power and photovoltaic power consumption at time t under scenario s, the abandoned wind and photovoltaic power, and the unit output of wind power and photovoltaic power at the current moment, (2g)(2h) is the maximum abandoned wind and photovoltaic power constraint, where λ PV and λ WT is the maximum permissible wind and solar curtailment rate of the system, SVG is a reactive power compensation device that can achieve continuous regulation of reactive power, optimize voltage distribution in the distribution system and power transmission level in the line. Formula (2i) is the installation capacity and location constraints of SVG, is a binary variable indicating whether SVG is installed at node i. is the maximum allowed installed SVG capacity at node i; Formula (2j) is the output power constraint of SVG, is the reactive power output of node i at time t in scenario s, β min and β max They are the down-adjustment coefficient and up-adjustment coefficient of SVG output respectively. In addition to using distributed power sources, the distribution system also needs to obtain power from the main grid to compensate for the intermittent output of distributed renewable energy and adjust the peak-to-valley difference of the distribution system. Considering the construction and expansion of substations to meet the operation of the distribution system, Formulas (2k)-(2l) are the capacity constraints of the substation. Reactive power provided to the substation, K sub is the maximum load of the substation, They are the newly built rated capacity of the substation at node i, the initial capacity of the substation and the rated capacity that can be expanded; As a back-to-back power electronic device, SOP consists of two converters, VSC1 and VSC2, with capacitors connected in parallel between the two converters, which can provide reactive power to the nodes at both ends of the feeder; Formula (2m)-(2q) is the mathematical model of SOP during operation. are the active power, reactive power, active loss, capacity and loss coefficient of the converter at node i connected to the soft switch under scenario s at time t, respectively. Formula (2m) is the power balance constraint within the SOP; (2n) and (2o) are the active power losses at both ends of the SOP; (2p)-(2q) are the capacity constraints of the commutation equipment at the SOP access point; Next, the grid-side model is built. The distribution network needs to always maintain radial operation. The network topology constraints of newly built substations and newly added load nodes are as follows: |y ij |≤(n-n s0 )x ij ,(i,j)∈Ω L (3e) In formula (3a), N is the number of newly added load nodes. This constraint means that the newly added load nodes must be equal to the number of newly added lines to ensure that the lines are radial. However, this constraint alone cannot satisfy the requirement that the distribution network containing distributed power sources maintains radial operation. The access of distributed power sources will cause node island operation and even lead to the emergence of a ring network. Therefore, constraints (3b)-(3e) are required for further restrictions. In constraint (3b), y ij is the virtual power flow from node i to node j, n is the number of nodes in the line, n s0 is the number of existing substations in the network. This constraint limits the maximum virtual power flow that can be generated by the existing substation node. Constraint (3c) indicates that when the node is a newly built substation node, the constraint degenerates to the substation node shown in (3b). When the substation node is not built, the constraint degenerates to the virtual load node in (3d). Constraint (3d) indicates that when the node is a load node, the sum of the virtual power flows passing through the node is -1, that is, it is a virtual load. Constraint (3e) indicates that when the line is put into construction, the virtual power flow can be transmitted on the line, otherwise it cannot be transmitted. The linearized DistFlow power flow model is used to ignore the non-convex terms of network loss to simplify the calculation complexity of the final model. U i,t,s -U j,t,s ≥M(1-x ij )+(r ij P ij,t,s +x ij Q ij,t,s ) / V0 (i,j)∈Ω L (3i) U min ≤U i,t,s ≤U max i∈Ω n (3j) Formula (3f) and Formula (3g) are the active and reactive power balance constraints of the node. P ij,t,s , Q ij,t,s are the active and reactive power injected into node i at time t in scenario s, the active load and reactive load of the node, and the active and reactive power transmitted from node i to node j. Equations (3h)-(3i) are the DistFlow power flow models after linearization with network loss ignored, where U i,t,s ,M, V0 is the voltage of node i at time t in scenario s, a sufficiently large positive number, the impedance and inductance of the line between nodes ij, and the calibrated voltage of the distribution system. Formula (3j) is a safety constraint to ensure that the voltage of each node is within the allowable range, where U min and U max are the upper and lower voltage limits allowed by the node, and formula (3k) is the capacity constraint of the line, where S ij is the maximum capacity of the transmission line; Considering the demand side response, the excessive load response is reduced on the load side, where the load reduction is related to the load level, as shown in formula (3i). Formulas (3m)-(3n) are the active and reactive power injected into each node in the distribution system. In formula (31), ξ i is the maximum load reduction ratio at node i, and its value is related to the load level. is the active power reduced by node i at time t in scenario s, and equations (3m)-(3n) are the active and reactive powers injected into the node, where is the power of the electric vehicle swap station at node i at time t in scenario s; Finally, there are the constraints on the location and capacity of energy storage and electric vehicle battery swap stations. Equations (4a)-(4f) are the charging and discharging constraints of energy storage batteries: Formula (4a) is the installation constraint of the energy storage battery. and is a binary variable indicating whether energy storage is installed at node i and the maximum energy storage installation capacity allowed at the node. Equations (4b)-(4d) are the operating state constraints of the energy storage battery, where is a binary variable representing the battery charging and discharging status; k ch , k dis is the charge and discharge depth of the energy storage battery, and equations (4e)-(4f) are the capacity constraints of the energy storage battery charge and discharge. η ch , η ch is the amount of electricity stored in the energy storage battery at node i at time t in scenario s, and the battery charging and discharging efficiency; The specific site selection constraints for electric vehicle battery swap stations are as follows: Formula (4g) is the location constraint of electric vehicles. represents the location set of the i-th electric vehicle swap station, is a binary variable for whether to select a site for construction; Ω ev is the set of battery swap stations to be sited, and formula (4h) is the power constraint on the node after the battery swap station is sited; Step 3: Establish a new distribution system recovery model under fault operation scenario: Since the power distribution system is an integral whole, a line fault will directly affect the normal operation of other components of the power distribution system. When a fault occurs in the power distribution system, the remote control switch (RCS) can isolate the fault and prevent the fault from spreading, so as to ensure the normal operation of most nodes in the power distribution system. The first is the isolation phase after the fault occurs. When a fault occurs in the distribution system, the RCS can isolate the fault on the line and prevent the further spread of the accident. In the isolation phase, constraints (5a)-(5e) are satisfied. 0≤a ij ≤x ij (i,j)∈Ω L (5e) Formula (5a) represents the line fault constraint, f ij,s 1 indicates that line ij fails in the sth scenario; a ij It is a binary variable for installing RCS. 1 means that line ij has installed RCS. is the connection status of line ij after the fault occurs, T f is the time period when the fault occurs, and equations (5b)-(5d) are fault isolation diffusion constraints, where Indicates that node i is in scene s T f The state variable of whether the fault occurs at a certain moment. These four constraints can simulate the fault diffusion process of the distribution system and the blocking state of RCS to the fault. Formula (5e) shows that RCS can only be installed on the line, and RCS cannot be installed on the line without planning. In the fault scenario, the node failure will directly affect the normal operation of distributed power supply, energy storage, SOP and other power electronic equipment. After the fault occurs, it is necessary to cut it out from the fault location to protect the safety of the equipment. The specific constraint model after the fault is shown in equations (5f)-(5n): Formulas (5f)-(5n) are the output constraints of wind turbines, photovoltaic units, battery energy storage, SVG, SOP, new substations, and expanded substations under fault scenarios. After a fault occurs, the system needs to cut off a certain amount of load to ensure the normal operation of the remaining systems. In the fault scenario, the load loss must satisfy constraints (5o)-(5p): When a distribution system fails, the post-fault recovery process must be considered to determine the maximum power supply recovery plan for the distribution system. When the corresponding line is repaired, the node fault is cleared and constraints (5q)-(5v) are satisfied during the repair process: n i,t,s ≥n i,t+1,s i∈Ω n (5s) Formula (5q) represents the constraint on the maximum number of lines restored per hour, where R is the maximum number of lines that can be restored per hour; Formula (5r) is the line repair constraint, T re is the period of complete fault repair, indicating that all faulty lines must be repaired within a specified time after the fault occurs; Formulas (5s)-(5t) are fault recovery constraints. During the line repair process, the faults of the nodes at both ends of the faulty line are cleared when the line is repaired, where Ω F is the set where the faulty line is located; Formulas (5u)-(5v) ensure that the fault states of the two ends of the same line are the same without installing RCS during the fault recovery process. After installing RCS, if there is a fault at one end of the line, it can be isolated; Step 4: Solve the source-grid-load-storage coordination planning of the new distribution system: The objective function in step 1 and the constraints in the normal operation scenario and the fault operation scenario in steps 2-3 are modeled in MATLAB using YALMIP and solved using the commercial solver Cplex. Step 5: Establish an evaluation system to demonstrate the role of SOP access in improving distribution network operation: After obtaining the optimal configuration capacity of the system, the values ​​of various indicators of the system with and without SOP access are calculated respectively, and the various indicators are compared to prove that the system can achieve better performance under the access of SOP. In formula (6a), L mean is the maximum average load level of the line channel; V in formula (6b) mean is the maximum average voltage deviation level of the system during operation, where V norm is the system's nominal voltage; in formula (6c) represents the maximum load loss ratio in all scenarios after a system failure; in formula (6d) It represents the average time required for load recovery under all fault scenarios. is the time required for the load to be fully restored under fault scenario s, and formula (6e) represents the average recovery rate of the system load at a single moment under the fault scenario.

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