A method and terminal for analyzing the carrying capacity of distributed power sources considering the accommodation rate

Abstract

The present invention discloses a method and a terminal for analyzing the carrying capacity of distributed power sources considering the consumption rate. The existing grid structure of the distribution network is obtained, and the actually consumable distributed power output of each level in the existing grid structure of the distribution network is calculated to obtain the consumption rate of all distributed power sources. Based on the line capacity, the line voltage, and the consumption rate of all distributed power sources, the carrying capacity of the line is evaluated to obtain the line carrying capacity evaluation result. Based on the transformer equipment capacity, the carrying capacity of the transformer is evaluated to obtain the transformer carrying evaluation result. Based on the line carrying capacity evaluation result and the transformer carrying evaluation result, the line and the transformer are coupled and evaluated to obtain the regional carrying capacity evaluation result, making the analysis of the carrying capacity of distributed power sources more comprehensive, so as to achieve a more accurate and effective carrying capacity evaluation in the case of distributed power source access and realize the optimal consumption of distributed power sources by the distribution network.

Description

Technical Field

[0001] The present invention relates to the technical field of distribution networks, and particularly to a method and a terminal for analyzing the carrying capacity of distributed power sources considering the consumption rate. Background Art

[0002] The wide access of distributed generators (DGs) is an inevitable trend of future distribution networks. On the one hand, the grid connection of DGs changes the structural form and operating characteristics of distribution networks; on the other hand, problems such as line overload, voltage over-limit, and power reverse injection will occur during the process of distribution networks consuming intermittent DGs such as photovoltaic power. In recent years, with the gradual increase in the penetration rate of distributed photovoltaics in distribution networks, objectively evaluating the adaptability of distribution networks to distributed photovoltaics has become one of the important issues in the current distribution system planning and operation process.

[0003] The adaptability of the power grid to DGs is generally characterized by "carrying capacity" and "consumption rate", and certain research results on the adaptability of distributed power sources have been obtained. Some results propose an evaluation method for the carrying capacity of distributed photovoltaics in distribution networks by analyzing the limiting factors affecting the consumption rate of DGs and based on the actual operating state and safety boundary of the distribution network; some other results propose a consumption rate evaluation method considering optimal power flow and chronological production simulation. However, general research evaluates the carrying capacity of distributed power sources under the condition of no curtailment of electricity, or calculates the consumption rate of the power grid for distributed power sources when the access situation of distributed power sources is determined. There is no research yet to propose a method for analyzing the carrying capacity of distributed power sources considering the consumption rate. In fact, if the curtailment of electricity is not allowed during the carrying capacity analysis process (i.e., the consumption rate reaches 100%), due to the existence of extreme scenarios with extremely light loads and extremely large outputs of distributed power sources, the access capacity of distributed power sources will be greatly restricted. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: to provide a method and a terminal for analyzing the carrying capacity of distributed power sources considering the consumption rate, which can achieve more accurate and effective carrying capacity evaluation when distributed power sources are connected.

[0005] To solve the above technical problem, a technical solution adopted by the present invention is:

[0006] A method for analyzing the carrying capacity of distributed power sources considering the consumption rate, comprising the steps of:

[0007] Obtain the existing grid structure of the distribution network, and calculate the actually consumable output of distributed power sources at each level in the existing grid structure of the distribution network to obtain the consumption rate of all distributed power sources;

[0008] Evaluate the carrying capacity of the line based on the line capacity, line voltage, and the absorption rate of all the distributed power sources to obtain the line carrying capacity evaluation result;

[0009] Evaluate the carrying capacity of the transformer based on the transformer equipment capacity to obtain the transformer carrying evaluation result;

[0010] Perform a coupling evaluation on the line and the transformer based on the line carrying capacity evaluation result and the transformer carrying evaluation result to obtain the regional carrying capacity evaluation result.

[0011] To solve the above technical problems, another technical solution adopted by the present invention is:

[0012] A distributed power source carrying capacity analysis terminal considering the absorption rate, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the following steps are implemented:

[0013] Obtain the existing grid structure of the distribution network, and calculate the actually absorbable output of the distributed power sources at each level in the existing grid structure of the distribution network to obtain the absorption rate of all the distributed power sources;

[0014] Evaluate the carrying capacity of the line based on the line capacity, line voltage, and the absorption rate of all the distributed power sources to obtain the line carrying capacity evaluation result;

[0015] Evaluate the carrying capacity of the transformer based on the transformer equipment capacity to obtain the transformer carrying evaluation result;

[0016] Perform a coupling evaluation on the line and the transformer based on the line carrying capacity evaluation result and the transformer carrying evaluation result to obtain the regional carrying capacity evaluation result.

[0017] The beneficial effects of the present invention are as follows: Calculate the actual absorbable distributed power output of each level in the existing grid structure of the distribution network to obtain the absorption rate of all distributed power sources. Evaluate the carrying capacity of the line based on the line capacity, line voltage, and the absorption rate of all distributed power sources to obtain the line carrying capacity evaluation result. Evaluate the carrying capacity of the transformer based on the transformer equipment capacity to obtain the transformer carrying evaluation result. Perform a coupling evaluation on the line and the transformer based on the line carrying capacity evaluation result and the transformer carrying evaluation result to obtain the regional carrying capacity evaluation result. In this way, the analysis of the carrying capacity of distributed power sources is realized. The carrying capacity of transformers and lines at all levels of the distribution network is evaluated by a top-down method, and the absorption rate of distributed power sources during the operation of the distribution network is considered at the same time, making the analysis of the carrying capacity of distributed power sources more comprehensive, so as to achieve a more accurate and effective carrying capacity evaluation in the case of distributed power source access, and further realize the optimal absorption of distributed power sources by the distribution network. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 FIG. is a flowchart of the steps of a method for analyzing the carrying capacity of distributed power sources considering the absorption rate according to an embodiment of the present invention;

[0019] Figure 2 FIG. is a schematic structural diagram of a terminal for analyzing the carrying capacity of distributed power sources considering the absorption rate according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] To describe the technical content, achieved objectives, and effects of the present invention in detail, the following is described in conjunction with the embodiments and accompanied by the drawings.

[0021] Please refer to Figure 1 , an embodiment of the present invention provides a method for analyzing the carrying capacity of distributed power sources considering the absorption rate, including the steps of:

[0022] Obtain the existing grid structure of the distribution network, and calculate the actual absorbable distributed power output of each level in the existing grid structure of the distribution network to obtain the absorption rate of all distributed power sources;

[0023] Evaluate the carrying capacity of the line based on the line capacity, line voltage, and the absorption rate of all distributed power sources to obtain the line carrying capacity evaluation result;

[0024] Evaluate the carrying capacity of the transformer based on the transformer equipment capacity to obtain the transformer carrying evaluation result;

[0025] Perform a coupling evaluation on the line and the transformer based on the line carrying capacity evaluation result and the transformer carrying evaluation result to obtain the regional carrying capacity evaluation result.

[0026] As can be seen from the above description, the beneficial effects of the present invention are as follows: calculating the actual absorbable distributed power output of each level in the existing grid structure of the distribution network to obtain the absorption rates of all distributed power sources, evaluating the carrying capacity of the line based on the line capacity, line voltage, and the absorption rates of all distributed power sources to obtain the line carrying capacity evaluation result, evaluating the carrying capacity of the transformer based on the transformer equipment capacity to obtain the transformer carrying evaluation result, and performing a coupling evaluation on the line and the transformer based on the line carrying capacity evaluation result and the transformer carrying evaluation result to obtain the regional carrying capacity evaluation result, thereby realizing the analysis of the carrying capacity of distributed power sources. Using a top-down method to evaluate the carrying capacity of transformers and lines at all levels of the distribution network, and considering the absorption rate of distributed power sources during the operation of the distribution network at the same time, making the analysis of the carrying capacity of distributed power sources more comprehensive, so as to achieve a more accurate and effective carrying capacity evaluation under the condition of distributed power source access, and further realizing the optimal absorption of distributed power sources by the distribution network.

[0027] Further, the calculating the actual absorbable distributed power output of each level in the existing grid structure of the distribution network to obtain the absorption rates of all distributed power sources includes:

[0028] Determining a first objective function with the maximum absorption rate of distributed power sources as the optimization goal;

[0029] Obtaining the active power output and reactive power output of the distributed power source, and determining the distributed power source operation output constraint based on the active power output and the reactive power output;

[0030] Obtaining the current magnitude of the line, and determining the line transmission current-carrying capacity constraint based on the current magnitude;

[0031] Calculating the actual absorbable distributed power output of each level in the existing grid structure of the distribution network based on the first objective function, the distributed power source operation output constraint, and the line transmission current-carrying capacity constraint to obtain the absorption rates of all distributed power sources.

[0032] As can be seen from the above description, since the main factors affecting the absorption rate are the power flow equation, node voltage, current-carrying capacity, and distributed power source operation output of the distribution network, calculating the actual absorbable distributed power output of each level in the existing grid structure of the distribution network based on the first objective function, the distributed power source operation output constraint, and the line transmission current-carrying capacity constraint to obtain the absorption rate of the distributed power source, and realizing the calculation of the actual absorbable distributed power output of each level.

[0033] Further, the determining a first objective function with the maximum absorption rate of distributed power sources as the optimization goal includes:

[0034] ;

[0035] In the formula, F represents the accommodation rate of the distribution network to distributed power sources, and S max represents the total number of scenarios, and P DG,i represents the actual power generation of the distributed power source under scenario i, and represents the theoretical power generation of the distributed power source under scenario i.

[0036] As can be seen from the above description, by determining the first objective function with the maximum accommodation rate of distributed power sources as the optimization goal, the maximum accommodation rate of distributed power sources can be calculated, thereby providing a theoretically optimal solution for the connection of distributed power sources, and further realizing the optimal accommodation of distributed power sources by the distribution network.

[0037] Furthermore, the determination of the operating output constraints of distributed power sources based on the active power output and the reactive power output includes:

[0038] ;

[0039] In the formula, P DG,i ′ represents the active power output of the i-th distributed power source, and Q DG,i represents the reactive power output of the i-th distributed power source, represents the lower limit of the active power output of the i-th distributed power source, represents the upper limit of the active power output of the i-th distributed power source, represents the lower limit of the reactive power output of the i-th distributed power source, represents the upper limit of the reactive power output of the i-th distributed power source;

[0040] The determination of the line transmission current-carrying capacity constraint based on the current magnitude includes:

[0041] ;

[0042] In the formula, I k represents the current magnitude on the k-th line, and represents the maximum value of the current magnitude on the k-th line.

[0043] As can be seen from the above description, during the operation phase, it is necessary to satisfy the node voltage and power flow constraints of the distribution network, as well as the output power constraints of distributed power sources and the line transmission current-carrying capacity constraints, etc., so as to realize the accurate measurement of the accommodation rate of distributed power sources.

[0044] Furthermore, the evaluation of the line carrying capacity based on the line capacity, line voltage, and the accommodation rate of all distributed power sources to obtain the line carrying capacity evaluation result includes: <s

[0045] Select the lines within the range to be evaluated;

[0046] Determine the end node of the line as the PV access point, and construct the second objective function with the maximum PV installation capacity of the line as the optimization objective;

[0047] Determine the node voltage constraint, line power flow constraint, line capacity constraint, and the accommodation rate constraint of distributed power sources;

[0048] Evaluate the carrying capacity of the line based on the second objective function, the node voltage constraint, line power flow constraint, line capacity constraint, and the accommodation rate constraint of distributed power sources, and obtain the evaluation result of the line carrying capacity.

[0049] As can be seen from the above description, since the main factors restricting the PV carrying capacity of a single-layer line are line capacity and line voltage, evaluating the carrying capacity of the line based on the second objective function, node voltage constraint, line power flow constraint, line capacity constraint, and the accommodation rate constraint of distributed power sources can make the evaluation result of the line carrying capacity more in line with the actual situation and more accurate.

[0050] Further, the construction of the second objective function with the maximum PV installation capacity of the line as the optimization objective includes:

[0051] max S DG ;

[0052] where S DG represents the PV installation capacity.

[0053] As can be seen from the above description, the general method for evaluating the carrying capacity of a line is to select the end node of the line as the PV access point to maximize the PV installation capacity of the line, and then calculate the carrying capacity of the line in combination with the constraint conditions.

[0054] Further, the node voltage constraint is:

[0055] ;

[0056] where V i,min represents the lower voltage limit for the safe operation of distribution line node i, V i,t represents the voltage of distribution line node i at time t, and V i,max represents the upper voltage limit for the safe operation of distribution line node i;

[0057] The line power flow constraint is:

[0058] ;

[0059] where represents the active power load of node j at time t, represents the active power of PV of node j at time t, represents the reactive load of node j at time t, P jk,t represents the active power of the jk branch at time t, P ij,t represents the active power of the ij branch at time t, Q jk,t represents the reactive power of the jk branch at time t, Q ij,t represents the reactive power of the ij branch at time t, V j,t represents the node voltage of node j at time t, r ij represents the resistance of the ij branch, x ij represents the reactance of the ij branch;

[0060] The line capacity constraint is:

[0061] ;

[0062] Where S ij represents the line capacity of the ij branch;

[0063] The consumption rate constraint of the distributed power source is:

[0064] ;

[0065] Where F represents the absorption rate of the distribution network to distributed power sources, F min It indicates the minimum limit of the distribution network's consumption rate for distributed generation.

[0066] As can be seen from the above description, the current ways for distributed power sources to access the distribution network are mainly divided into line access and transformer access. The distributed power sources connected to the local grid will have an impact on the carrying capacity of the upper and lower grids. By establishing the above constraints, the line carrying capacity is evaluated separately without considering the impact of the upper and lower grid components on it.

[0067] Furthermore, the transformer load capacity is evaluated based on the transformer equipment capacity to obtain the transformer load evaluation result, which includes:

[0068] ;

[0069] Where k i Represents the photovoltaic output coefficient, S DG Represents the photovoltaic installed capacity, Indicates the total load carried by the transformer, S N Indicates the rated capacity of the transformer.

[0070] As can be seen from the above description, the factor restricting the PV carrying capacity of the transformer is the equipment capacity. For transformer equipment below 110 kV and below, when the coupling relationship between equipment is not considered, distributed PV can be connected to the transformer through dedicated lines, and its PV carrying capacity is not restricted by factors such as line power flow. Its value is closely related to 80% of the rated capacity of the transformer equipment. Therefore, the above formula can be used to evaluate the carrying capacity of the transformer.

[0071] Further, the coupling evaluation of the line and the transformer based on the line carrying capacity evaluation result and the transformer carrying evaluation result to obtain the regional carrying capacity evaluation result includes:

[0072] When considering the access of distributed power from the upper level, for the line, the transformer carrying evaluation result is determined as the boundary condition, and the PV carrying capacity of the line considering the direct impact of the transformer is evaluated according to the boundary condition, the node voltage constraint, the line power flow constraint, the line capacity constraint, and the absorption rate constraint of the distributed power to obtain the first PV carrying capacity;

[0073] For the transformer, the PV carrying capacity of the distribution transformer considering the impact of the distribution line is evaluated based on the transformer equipment capacity and the line carrying evaluation result to obtain the second PV carrying capacity;

[0074] The regional carrying capacity evaluation result is obtained according to the first PV carrying capacity and the PV carrying capacity. <8000218>As can be seen from the above description, further considering the interactive influence of the PV carrying capacity of the upper and lower components, so the line and the transformer are coupled and evaluated. At the same time, considering that the distribution network architecture is generally radial, the upper component generally connects multiple lower components and its capacity is greater than or equal to the sum of the connected lower components. Therefore, using a top-down carrying capacity evaluation structure can maximize the accurate evaluation of the carrying capacity of each component node in the region, so as to realize accurate and effective analysis of the distributed power carrying capacity.

[0076] Please refer to Figure 2 , Another embodiment of the present invention provides a distributed power carrying capacity analysis terminal considering the absorption rate, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, each step in the above-mentioned distributed power carrying capacity analysis method considering the absorption rate is implemented.

[0077] The above-mentioned distributed power carrying capacity analysis method and terminal of the present invention can be applied to the regional distribution network involving substations of multiple voltage levels, which will be described below through specific embodiments:

[0078] Embodiment 1

[0079] Please refer to Figure 1 , a method for analyzing the carrying capacity of distributed power sources considering the absorption rate in this embodiment, includes the steps:

[0080] S1. Obtain the existing grid structure of the distribution network, and calculate the actually absorbable distributed power output of each level in the existing grid structure of the distribution network to obtain the absorption rate of all distributed power sources, specifically including:

[0081] S11. Obtain the existing grid structure of the distribution network;

[0082] S12. Determine the first objective function with the maximum absorption rate of the distributed power source as the optimization target. Specifically:

[0083] ;

[0084] In the formula, F represents the absorption rate of the distributed power source by the distribution network, S max represents the total number of scenarios, P DG,i represents the actual power generation power of the distributed power source in scenario i, represents the theoretical maximum power generation power of the distributed power source in scenario i.

[0085] S13. Obtain the active power output and reactive power output of the distributed power source, and determine the operation output constraint of the distributed power source based on the active power output and the reactive power output. Specifically:

[0086] ;

[0087] In the formula, P DG,i ′ represents the active power output of the i-th distributed power source, Q DG,i represents the reactive power output of the i-th distributed power source, represents the lower limit of the active power output of the i-th distributed power source, represents the upper limit of the active power output of the i-th distributed power source, represents the lower limit of the reactive power output of the i-th distributed power source, represents the upper limit of the reactive power output of the i-th distributed power source;

[0088] S14. Obtain the magnitude of the current in the line, and determine the line transmission current-carrying capacity constraint based on the magnitude of the current. Specifically:

[0089] ;

[0090] In the formula, I k represents the magnitude of the current on the k-th line, represents the maximum value of the magnitude of the current on the k-th line.

[0091] S15. Calculate the actually consumable distributed power generation output of each level in the existing grid structure of the distribution network based on the first objective function, the operating output constraint of the distributed power source, and the line transmission current-carrying capacity constraint, and obtain the consumption rate of all distributed power sources.

[0092] S2. Evaluate the carrying capacity of the line based on the line capacity, line voltage, and the consumption rate of all distributed power sources, and obtain the line carrying capacity evaluation result, specifically including:

[0093] S21. Select the lines within the range to be evaluated;

[0094] In an optional implementation manner, select the 110 kV, 35 kV, and 10 kV lines within the range to be evaluated as the evaluation objects.

[0095] S22. Determine the end node of the line as the PV access point, and construct a second objective function with the maximum PV installation capacity of the line as the optimization goal, specifically including:

[0096]

[0097] In the formula, S DG represents the PV installation capacity, n is the total number of lines where the end node can access PV, represents the PV installation capacity of the i-th line.

[0098] S23. Determine the node voltage constraint, line power flow constraint, line capacity constraint, and the consumption rate constraint of the distributed power source;

[0099] Among them, the node voltage constraint is:

[0100] ;

[0101] In the formula, V i,min represents the lower voltage limit for the safe operation of distribution line node i, V i,t represents the voltage of distribution line node i at time t, V i,max represents the upper voltage limit for the safe operation of distribution line node i;

[0102] The line power flow constraint is:

[0103] ;

[0104] In the formula, represents the active power load of node j at time t, represents the active power of PV of node j at time t, represents the reactive power load of node j at time t, P jk,t represents the active power of the jk branch at time t, Pij,t Indicates the active power of the ij branch at time t, Q jk,t Indicates the reactive power of the jk branch at time t, Q ij,t Indicates the reactive power of the ij branch at time t, V j,t Indicates the node voltage of node j at time t, r ij Indicates the resistance of the ij branch, r ij Indicates the reactance of the ij branch;

[0105] The line capacity constraint is:

[0106] ;

[0107] In the formula, S ij Indicates the line capacity of the ij branch;

[0108] The accommodation rate constraint of the distributed power source is:

[0109] ;

[0110] In the formula, F represents the accommodation rate of the distribution network to the distributed power source, F min Indicates the minimum limit value of the accommodation rate of the distribution network to the distributed power source.

[0111] S24. Evaluate the carrying capacity of the line based on the second objective function, the node voltage constraint, the line power flow constraint, the line capacity constraint, and the accommodation rate constraint of the distributed power source to obtain the line carrying capacity evaluation result.

[0112] S3. Evaluate the carrying capacity of the transformer based on the transformer equipment capacity to obtain the transformer carrying capacity evaluation result. Specifically:

[0113] ;

[0114] In the formula, k i Indicates the photovoltaic output coefficient, S DG Indicates the photovoltaic installation capacity, Indicates all the loads carried by the transformer, S N Indicates the rated capacity of the transformer.

[0115] The factor restricting the photovoltaic carrying capacity of the transformer is the equipment capacity. For transformer equipment below 110 kV and below, when the coupling relationship between equipment is not considered, distributed photovoltaics can be connected to the transformer through a dedicated line, and its photovoltaic carrying capacity is not restricted by factors such as line power flow. Its value is closely related to 80% of the rated capacity of the transformer equipment. Therefore, the above formula is used for evaluation.

[0116] S4. Based on the line carrying capacity evaluation result and the transformer carrying capacity evaluation result, perform a coupling evaluation on the line and the transformer to obtain the regional carrying capacity evaluation result. For the coupling evaluation of the line and the transformer, in the order from high voltage to low voltage, respectively consider the evaluation of the photovoltaic carrying capacity of the transformer considering the influence of the superior distribution line or the evaluation of the photovoltaic carrying capacity of the distribution line considering the influence of the superior transformer. In an optional implementation manner, the specific evaluation order is as follows:

[0117] (1) Evaluate the photovoltaic carrying capacity of the 110 kV transformer;

[0118] (2) Evaluate the photovoltaic carrying capacity of the line below 10 kV considering the direct influence of the 110 kV transformer;

[0119] (3) Evaluate the photovoltaic carrying capacity of the distribution transformer considering the influence of the 10 kV distribution line, specifically including:

[0120] S41. When considering the access of distributed power from the superior, for the line, determine the transformer carrying capacity evaluation result as the boundary condition, and perform a photovoltaic carrying capacity evaluation on the line considering the direct influence of the transformer according to the boundary condition, the node voltage constraint, the line power flow constraint, the line capacity constraint, and the distributed power consumption rate constraint to obtain the first photovoltaic carrying capacity;

[0121] S42. For the transformer, perform a photovoltaic carrying capacity evaluation on the distribution transformer considering the influence of the distribution line based on the transformer equipment capacity and the line carrying capacity evaluation result to obtain the second photovoltaic carrying capacity;

[0122] S43. Obtain the regional carrying capacity evaluation result according to the first photovoltaic carrying capacity and the photovoltaic carrying capacity.

[0123] Taking the line as an example, the coupling type of the photovoltaic carrying capacity evaluation of the distribution line considering the influence of the superior transformer, that is, the coupling method of multiple lines connected under the transformer, needs to consider the size relationship between the sum of the photovoltaic carrying capacities of each line and the photovoltaic carrying capacity of the superior transformer. If the sum of the photovoltaic carrying capacities of each line is less than the photovoltaic carrying capacity of the superior transformer, the multi-level photovoltaic carrying capacity of each line is the same as its single-level photovoltaic carrying capacity. If the sum of the photovoltaic carrying capacities of each line is greater than the photovoltaic carrying capacity of the superior transformer, mark the superior transformer as the bottleneck element. In this case, if the photovoltaic carrying capacity of a certain line is greater than the photovoltaic carrying capacity of the superior transformer, the carrying capacity of this line is changed to the photovoltaic carrying capacity of the superior transformer as the result of the multi-level photovoltaic carrying capacity.

[0124] Currently, the main ways for distributed generators (DGs) to access the distribution network are through lines and through transformers. The DGs connected to the grid at this level will affect the carrying capacity of the upper / lower grids. Therefore, the present invention first establishes a single-level evaluation model, that is, the line carrying capacity or transformer carrying capacity is evaluated separately, without considering the impact of the upper and lower grid components on it; further, considering the interactive impact of the photovoltaic carrying capacity of the upper and lower components, a regional carrying capacity evaluation model for transformer and line coupling evaluation is proposed. At the same time, considering that the distribution network architecture is generally radial, the upper component is generally connected to multiple lower components and the capacity is greater than or equal to the sum of the connected lower components, so the use of a top-down carrying capacity evaluation structure can maximize the accuracy of evaluating the carrying capacity of each component node in the region.

[0125] The distribution network's distributed power carrying capacity assessment part and the distributed power consumption rate calculation part are applicable to different stages of the distribution network. The former is applicable to the planning stage, and the latter is applicable to the operation stage.

[0126] Example 2

[0127] Please refer to Figure 2 In this embodiment, a terminal for analyzing the carrying capacity of distributed power sources taking into account the absorption rate is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, each step of the method for analyzing the carrying capacity of distributed power sources taking into account the absorption rate in the first embodiment is implemented.

[0128] In summary, the present invention provides a distributed power supply carrying capacity analysis method and terminal considering the absorption rate, which obtains the existing grid structure of the distribution network, and calculates the actual absorbable distributed power output of each level in the existing grid structure of the distribution network to obtain the absorption rate of all distributed power sources; evaluates the carrying capacity of the line based on the line capacity, line voltage and the absorption rate of all distributed power sources to obtain a line carrying capacity evaluation result; evaluates the carrying capacity of the transformer based on the transformer equipment capacity to obtain a transformer bearing evaluation result; and performs a coupling evaluation of the line and the transformer based on the line bearing capacity evaluation result and the transformer bearing evaluation result to obtain a regional carrying capacity evaluation result, thereby realizing the analysis of the distributed power supply carrying capacity, and adopts a top-down method to evaluate the carrying capacity of transformers and lines at all levels of the distribution network, while considering the distributed power supply absorption rate during the operation process of the distribution network, making the distributed power supply carrying capacity analysis more comprehensive, thereby achieving a more accurate and effective carrying capacity evaluation when distributed power sources are connected, and thus realizing the optimal absorption of distributed power sources by the distribution network.

[0129] The above are only embodiments of the present invention, and thus do not limit the patent scope of the present invention. Any equivalent transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in related technical fields, shall be similarly included in the patent protection scope of the present invention.

Claims

1. A method for analyzing the carrying capacity of distributed power sources considering the accommodation rate, characterized in that Including the steps: Obtain the existing grid structure of the distribution network, calculate the actual absorbable distributed power generation output of each level in the existing grid structure of the distribution network, and obtain the absorption rate of all distributed power generations; Evaluate the carrying capacity of the line based on the line capacity, line voltage, and the absorption rate of all distributed power generations, and obtain the line carrying capacity evaluation result; Evaluate the carrying capacity of the transformer based on the transformer equipment capacity, and obtain the transformer carrying capacity evaluation result; Perform a coupling evaluation on the line and the transformer based on the line carrying capacity evaluation result and the transformer carrying capacity evaluation result, and obtain the regional carrying capacity evaluation result; The obtaining the absorption rate of all distributed power generations includes: Determine the first objective function with the maximum absorption rate of the distributed power generation as the optimization objective; Obtain the active power output and reactive power output of the distributed power generation, and determine the distributed power generation operation output constraint based on the active power output and the reactive power output; Obtain the magnitude of the current in the line, and determine the line transmission current carrying capacity constraint based on the magnitude of the current; Calculate the actual absorbable distributed power generation output of each level in the existing grid structure of the distribution network based on the first objective function, the distributed power generation operation output constraint, and the line transmission current carrying capacity constraint, and obtain the absorption rate of all distributed power generations; The determining the first objective function includes: ； where F represents the accommodation rate of the distribution network to distributed power sources, s max represents the total number of scenarios, P DG,i represents the actual power generation of the distributed power source under scenario i, and represents the theoretical power generation of the distributed power source under scenario i; The determining the distributed power generation operation output constraint includes: ； Where, P DG,i ' represents the active power output of the i-th distributed power source, Q DG,i represents the reactive power output of the i-th distributed power source, represents the lower limit of the active power output of the i-th distributed power source, represents the upper limit of the active power output of the i-th distributed power source, represents the lower limit of the reactive power output of the i-th distributed power source, represents the upper limit of the reactive power output of the i-th distributed power source; The determining the line transmission current carrying capacity constraint based on the magnitude of the current includes: ； Where I k represents the magnitude of the current on the k-th line, represents the maximum value of the magnitude of the current on the k-th line; The obtaining the line carrying capacity evaluation result includes: Select the lines within the scope to be evaluated; Determine the end node of the line as the PV access point, and construct the second objective function with the maximum PV installation capacity of the line as the optimization objective; Determine the node voltage constraint, line power flow constraint, line capacity constraint, and absorption rate constraint of the distributed power generation; Evaluate the carrying capacity of the line based on the second objective function, the node voltage constraint, line power flow constraint, line capacity constraint, and absorption rate constraint of the distributed power generation, and obtain the line carrying capacity evaluation result; The obtaining the transformer carrying capacity evaluation result includes: ； where k t represents the PV output coefficient, S DG represents the PV installed capacity, represents all the loads carried by the transformer, S N represents the rated capacity of the transformer.

2. The method for analyzing the carrying capacity of distributed power sources considering the accommodation rate according to claim 1, characterized in that The constructing the second objective function with the maximum PV installation capacity of the line as the optimization objective includes: max S DG ; Wherein, S DG represents the photovoltaic installation capacity.

3. The distributed power source carrying capacity analysis method considering the accommodation rate according to claim 1, wherein The node voltage constraint is: ； where V i,min represents the lower voltage limit for the safe operation of the distribution line node i, V i,t represents the voltage of the distribution line node i at time t, V i,max represents the upper voltage limit for the safe operation of the distribution line node i; The line power flow constraint is: ； In the formula, represents the active power load of node j at time t, represents the active power of the photovoltaic power at node j at time t, represents the reactive power load of node j at time t, P jk,t represents the active power of branch jk at time t, P ij,t represents the active power of branch ij at time t, Q jk,t represents the reactive power of branch jk at time t, Q ij,t represents the reactive power of branch ij at time t, V j,t represents the node voltage of node j at time t, r ij represents the resistance of branch ij, x ij represents the reactance of branch ij; The line capacity constraint is: ； where S ij represents the line capacity of the ij branch; The absorption rate constraint of the distributed power generation is: ； Where F represents the accommodation rate of the distribution network to distributed power sources, F min represents the minimum limit value of the accommodation rate of the distribution network to distributed power sources.

4. A method for analyzing the carrying capacity of distributed power sources considering the accommodation rate according to claim 1, characterized in that The performing a coupling evaluation on the line and the transformer based on the line carrying capacity evaluation result and the transformer carrying capacity evaluation result, and obtaining the regional carrying capacity evaluation result includes: When considering the access of the distributed power generation from the upper level, for the line, determine the transformer carrying capacity evaluation result as the boundary condition, and perform a PV carrying capacity evaluation on the line considering the direct influence of the transformer according to the boundary condition, the node voltage constraint, line power flow constraint, line capacity constraint, and absorption rate constraint of the distributed power generation, and obtain the first PV carrying capacity; For the transformer, based on the capacity of the transformer equipment and the evaluation result of the line load, the photovoltaic carrying capacity of the distribution transformer considering the influence of the distribution line is evaluated to obtain the second photovoltaic carrying capacity. According to the first photovoltaic carrying capacity and the photovoltaic carrying capacity, the evaluation result of the regional carrying capacity is obtained.

5. A distributed power source carrying capacity analysis terminal considering the accommodation rate, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the computer program, it realizes each step in a distributed power source carrying capacity analysis method considering the consumption rate according to any one of claims 1 to 4.

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