A Multi-Region Multi-Stage Coordination Restoration Method and System for Power Grid and Power Plants

Abstract

The present invention discloses a multi-region and multi-stage plant-grid coordinated restoration method and system, which models the power system restoration problem by using a sub-region and sub-stage coordination method. In the power generation and transmission system, it considers maximizing the power generation of units under the reconstruction of the backbone network; in the distribution system with distributed power sources, it considers minimizing the load loss; by changing the plant-grid coordinated restoration penalty function to represent the contribution degree of distributed power sources in the distribution system to the power generation and transmission system at different time periods, it realizes the time-sharing support of the black start capability of distributed power sources for the power system restoration. The present invention can be used as an important auxiliary tool in the post-disaster restoration process of the power system, comprehensively providing sufficient decision-making guidance for power system operators and providing a reference for the identification of key nodes.

Description

Technical Field

[0001] The present invention belongs to the technical field of post-disaster restoration of power systems, and particularly relates to a multi-region and multi-stage coordinated restoration method and system for power plants and networks. Background Art

[0002] The restoration process of a power system can be divided into three stages: power source restoration, grid framework restoration, and load restoration. A reasonable power system restoration method can shorten the power outage time, minimize power outage losses, and thus improve the resilience level of the power system. Since the power system restoration is a multi-stage complex process, it is necessary to formulate corresponding restoration strategies for the post-disaster large-scale power outage scenario.

[0003] Generally, traditional generator sets are directly connected to the power generation and transmission system, while user loads are mainly connected to the distribution network. Therefore, existing research mainly models and solves the transmission network and distribution network systems separately. With the continuous increase in the penetration rate of distributed power sources in the power grid, the distribution network has the ability to participate in the restoration of the transmission network from bottom to top and can provide different supporting restoration effects at different stages. Therefore, how to establish a coordinated restoration method for power plants and networks in different regions and stages considering the black start ability of distributed power sources is a problem worthy of research. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a multi-region and multi-stage coordinated restoration method and system for power plants and networks in view of the deficiencies in the above-mentioned prior art. The method comprehensively considers the restoration processes of the power generation and transmission system and the distribution system, takes into account the supporting ability of distributed power sources for grid restoration at different times, overcomes the energy waste caused by separate modeling of power plants and networks in the prior art, and solves the problems existing in the prior art.

[0005] The present invention adopts the following technical solutions:

[0006] A multi-region and multi-stage coordinated restoration method for power plants and networks includes the following steps:

[0007] S1. Convert the objective function and constraints into a mixed-integer linear programming problem, and establish a power generation and transmission system restoration model;

[0008] S2. Establish a distribution system restoration model with the minimum load loss of the disconnected loads as the restoration objective;

[0009] S3. Divide the area to be restored according to the voltage level of the distribution system where it is located and the distance from the main generating units of the power generation system;

[0010] S^{4}. Adopt a strategy of changing the output of distributed power sources in the distribution system at different times, and divide the coordinated restoration stage of power plants and networks into the generator set black start stage, the backbone network reconstruction stage, and the important load restoration stage;

[0011] S5. The power transmission system recovery model established in step S1 and the distribution system recovery model established in step S2 are integrated to form a power system recovery model. Based on the result of the division of the to-be-restored area in step S3, a penalty function is introduced to optimize the generator set black start phase, the backbone network reconstruction phase, and the important load recovery phase divided in step S4, and a multi-region and multi-stage plant-grid coordinated recovery model is established.

[0012] S6. Solve the multi-region and multi-stage plant network coordinated recovery model established in step S5, formulate a regional and phased plant network coordinated recovery strategy, and realize multi-region and multi-stage plant network coordinated recovery.

[0013] Specifically, in step S1, the objective function of the power generation and transmission system restoration model is:

[0014]

[0015] in, is the maximum active power of the unit, is the ramp rate of unit i, is the unit operating time, The time required to prepare unit i for the ramp, is the power required to start unit j, is the unit start time, Yes all A collection of units, yes A collection of non-black start units.

[0016] Specifically, in step S1, the constraints of the power generation and transmission system restoration model are:

[0017] Critical time interval constraints

[0018]

[0019] Starting power requirement constraints:

[0020]

[0021] Unit power generation capacity constraints

[0022]

[0023]

[0024] Unit starting power constraint

[0025]

[0026] Auxiliary decision variable constraints

[0027]

[0028]

[0029]

[0030] Among them, 、 and are linear decision variables, and are binary decision variables, is the set of non-black start-up units, is the state of non-black start-up unit at each time slot, is the minimum value of the unit start-up time, is the unit start-up time, is the maximum value of the unit start-up time, is the number of the j-th unit, is the ramping rate of unit g, is the current time, is a binary decision variable, is the power required for unit g to start up, is the time required for unit g to prepare for ramping, is the unit operation time, is the maximum active power of unit g, is an auxiliary decision variable, is an auxiliary decision variable, is a binary decision variable, is a binary decision variable, .

[0031] Specifically, in step S2, the goal of the distribution system restoration is specifically:

[0032]

[0033] Among them, is the number of load nodes to be restored; is the restoration period; is the restoration status of the load on node at the j-th time period, is the importance degree of the load on node ; is the load loss on node .

[0034] Specifically, in step S3, the division conditions are specifically:

[0035] There is a main unit with black start capability in each restoration sub-region; each restoration sub-region contains at least one distribution system, and each distribution system belongs to only one restoration sub-region; two restoration sub-regions are connected by transmission lines.

[0036] Specifically, in step S4, during the black start stage of the generating unit, the available distributed power output in the distribution system is used for the black start of the generating unit; during the backbone network reconstruction stage, part of the distributed power output is used for the restoration of the power generation and transmission system, and part is used for the restoration of important loads in the distribution system; during the important load restoration stage, all the distributed power output is used for the restoration of loads in the distribution system.

[0037] Specifically, in step S5, the multi-region multi-stage plant-network coordinated restoration model is specifically as follows:

[0038]

[0039] Among them, is the plant-network coordinated restoration penalty function, is the objective function of the power generation and transmission system restoration model, is the objective function of the distribution system restoration model.

[0040] Furthermore, during the black start stage of the generating unit, ; during the backbone network reconstruction stage, ; during the important load restoration stage, .

[0041] Specifically, step S5 is specifically as follows:

[0042] According to the objective functions of the power generation and transmission system and the distribution system, use the hierarchical sequence method to focus on the main problems in turn, divide the restoration process into multiple stages for calculation; in each restoration period, first update the penalty function according to the status of the units in the power generation system, determine the support lease of the distributed power, then optimize according to the objective function and constraints, and finally update the available power according to the unit restoration results and restore the load; finally, obtain the optimized strategy for the unit startup sequence considering the backbone network reconstruction process and the load restoration optimization strategy based on the greedy algorithm to achieve post-disaster restoration decision-making.

[0043] In the second aspect, the embodiment of the present invention provides a multi-region multi-stage plant-network coordinated restoration system, including:

[0044] A conversion module that converts the objective function and constraints into a mixed integer linear programming problem to establish a power generation and transmission system restoration model;

[0045] An objective module that takes the minimum load loss of the disconnected loads as the restoration objective to establish a distribution system restoration model;

[0046] Partitioning module: partition the area to be restored according to the voltage level of the distribution system where it is located and the distance from the main generating units of the power generation system.

[0047] Changing module: adopt the strategy of changing the output of distributed power sources in the distribution system by time period, and divide the plant-network coordinated restoration stage into the black start stage of generating units, the backbone network reconstruction stage, and the important load restoration stage.

[0048] Restoring module: comprehensively form a power system restoration model by integrating the power transmission and transformation system restoration model established by the conversion module and the distribution system restoration model established by the target module. According to the results of the area division of the area to be restored in the partitioning module, introduce a penalty function to optimize the black start stage of generating units, the backbone network reconstruction stage, and the important load restoration stage divided by the changing module, and establish a multi-region and multi-stage plant-network coordinated restoration model.

[0049] Compared with the prior art, the present invention has at least the following beneficial effects:

[0050] A multi-region and multi-stage plant-network coordinated restoration method of the present invention models the power system restoration problem by using a method of coordinated division by region and stage. The obtained restoration strategy has the advantages of strong integrity, sufficient resource scheduling, and comprehensive calculation results compared with the traditional independent model. In the power transmission and transformation system, maximize the power generation of generating units under the reconstruction of the backbone network; in the distribution system containing distributed power sources (including new energy and energy storage), minimize the load loss. By changing the plant-network coordinated restoration penalty function to represent the contribution degree of distributed power sources in the distribution system to the power transmission and transformation system at different time periods, realize the time-sharing support of the black start ability of distributed power sources for power system restoration. This time-sharing plant-network coordinated restoration method can be used as an important auxiliary tool in the post-disaster restoration process of the power system, provide relatively comprehensive decision-making guidance for power system operators, and can provide reference for the identification of key nodes.

[0051] Furthermore, through the objective function of the power transmission and transformation system restoration model, a mathematical expression of the energy of the power transmission and transformation system is given, and the goal of the power transmission and transformation system restoration is clarified, providing a basis for the establishment of the power transmission and transformation system optimization model.

[0052] Furthermore, the constraint conditions of the power transmission and transformation system restoration model constrain the power transmission and transformation system at the physical level and the operation level, so that the optimization results can meet the basic physical principles and operation conditions, improve the power transmission and transformation system optimization model, and facilitate the solution of practical production problems.

[0053] Furthermore, the specific restoration objective function of the distribution system gives a mathematical expression of the total value of load restoration in the distribution system, and clarifies the goal of the distribution system restoration.

[0054] Furthermore, the large and complex power system is divided into multiple sub-regions through the regional division method, which facilitates parallel restoration according to the characteristics of the power grid in different regions after a disaster, rationally utilizes the supporting capacity of distributed power sources, and improves the resilience of the power grid.

[0055] Furthermore, a method for dividing the post-disaster restoration stage of a power system divides the coordinated restoration process of the power plant and the grid into three stages according to the different characteristics of the power system restoration process and the different supporting effects and output levels of distributed power sources on the power generation and transmission systems in different stages. It can adjust the output strategy of distributed power sources in a timely manner at different stages, and more reasonably and fully realize the rapid restoration of the entire power system.

[0056] Furthermore, a post-disaster restoration model of a power system coordinates the power generation and transmission system and the distribution system for restoration through a penalty function for coordinated restoration of the power plant and the grid. Compared with separate solutions, it can better allocate resources and avoid infeasible restoration strategies, and is more holistic and practical.

[0057] Furthermore, the penalty function in the post-disaster restoration model of the power system changes in stages, which can adjust the output strategy of distributed power sources according to the most urgent needs in different stages of the power system restoration process, make more full use of the supporting capacity of distributed power sources, and improve the restoration capacity of the entire power system.

[0058] Furthermore, the overall process of formulating the coordinated restoration strategy of the power plant and the grid comprehensively considers the restoration processes of the power generation and transmission system and the distribution system, realizes the coordinated restoration of the power plant and the grid, and at the same time considers the supporting capacity of distributed power sources for grid restoration at different times, overcomes the energy waste caused by separate modeling of the power plant and the grid in the existing technology, can provide decision-making guidance for power system operators more comprehensively, helps in formulating restoration strategies and identifying key nodes, and can be used as an important auxiliary tool in the post-disaster restoration process of the power system.

[0059] It can be understood that the beneficial effects of the second to third aspects above can refer to the relevant descriptions in the first aspect above, and will not be elaborated here.

[0060] In summary, compared with the traditional restoration strategy, the method of the present invention has the advantages of strong integrity, sufficient resource scheduling, and comprehensive calculation results; it gives the starting order of the main generating units on the power generation and transmission side, gives the load restoration amount on the distribution side, and gives the output situation of distributed power sources during the coordination process. Considering the power generation and transmission system and the distribution system comprehensively, it can formulate post-disaster restoration strategies more comprehensively, fully mobilize resources, and achieve bottom-up support; it can provide sufficient decision-making guidance for power system dispatchers in actual operation, and can provide reference for identifying key nodes.

[0061] The technical solutions of the present invention will be further described in detail below with reference to the drawings and embodiments. Description of the Drawings

[0062] Figure 1 It is a schematic diagram of the generating capacity function of the unit;

[0063] Figure 2 It is a schematic diagram of the starting power function of the unit;

[0064] Figure 3 It is a flow chart of the coordinated restoration of the plant and grid in sub - regions and stages of the present invention. Detailed Embodiment

[0065] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0066] In the description of the present invention, it should be understood that the terms "include" and "comprise" indicate the presence of the described features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0067] It should also be understood that the terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms.

[0068] It should be further understood that the term " / and" used in the specification of the present invention and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the context - related objects.

[0069] It should be understood that although the terms first, second, third, etc. may be used in the embodiments of the present invention to describe preset ranges, etc., these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range can also be referred to as the second preset range, and similarly, the second preset range can also be referred to as the first preset range.

[0070] Depending on the context, as used herein, the word "if" can be interpreted as "when" or "while" or "in response to determining" or "in response to detecting". Similarly, depending on the context, the phrase "if determined" or "if detected (stated condition or event)" can be interpreted as "when determined" or "in response to determining" or "when detected (stated condition or event)" or "in response to detecting (stated condition or event)".

[0071] Various structural schematic diagrams according to the disclosed embodiments of the present invention are shown in the accompanying drawings. These figures are not drawn to scale, where for the purpose of clear expression, some details are enlarged and some details may be omitted. The shapes of various regions and layers shown in the figures and their relative sizes and positional relationships are merely exemplary, and in practice, there may be deviations due to manufacturing tolerances or technical limitations, and those skilled in the art can design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0072] The present invention provides a multi-region multi-stage plant-network coordinated restoration method, which models the power system restoration problem by using a sub-region and sub-stage coordination method. In the power generation and transmission system, maximizing the power generation of units under the reconstruction of the backbone network is considered; in the distribution system containing distributed power sources (including new energy and energy storage), minimizing the load loss is considered. By changing the plant-network coordinated restoration penalty function to represent the contribution degree of distributed power sources in the distribution system to the power generation and transmission system at different time periods, the time-sharing support of the black start ability of distributed power sources for power system restoration is realized. The time-sharing plant-network coordinated restoration method of the present invention can be used as an important auxiliary tool in the post-disaster restoration process of the power system, providing sufficient decision-making guidance for power system operators more comprehensively, and can provide a reference for the identification of key nodes.

[0073] Please refer to Figure 3 , a multi-region multi-stage plant-network coordinated restoration method of the present invention includes the following steps:

[0074] S1. Establish a power generation and transmission system restoration model

[0075] S101. Define the objective function

[0076] The optimization objective is to maximize the power generation capacity of the entire system during the specified system restoration period; the system power generation capacity is defined as the sum of the power generation capacities of all units in the power system minus the sum of the required starting powers, expressed as:

[0077]

[0078] Wherein, is the power generation capacity of unit , ​ Startup requirements is the set of all sets of generating units is the set of non-black-start generating units.

[0079] S102. Add constraint conditions

[0080] Critical minimum and maximum interval constraints:

[0081]

[0082] Startup power requirement constraints:

[0083]

[0084] where is the generating capacity function of the generating unit, is the startup power function of non-black start.

[0085] S103. Linearize the objective problem

[0086] The above formula forms a non-linear combinatorial optimization problem. For the convenience of solution, it is transformed into a mixed-integer linear programming problem through the following four steps.

[0087] S1031. Introduce binary decision variables , and linear decision variables , , , and express the piecewise linear function of the generating capacity of the generating unit in the form of first-order and second-order;

[0088] The generating unit starts to ramp up at the point ( , 0) and reaches its maximum generating capacity at the point ( , ). The decision variables , , represent three sections respectively, , are responsible for restricting these three variables within the corresponding ranges. Then during the system restoration process, the capacity of each generating unit can be represented by the trapezoidal area in Figure 1 , that is:

[0089]

[0090] S1032. Introduce binary decision variables and linear decision variables , , the step function of the unit startup demand is expressed in the form of first and second order;

[0091] The non-black start-up unit receives startup power at the point ( , 0). The decision variables , represent two segments respectively, which are responsible for restricting these two variables within the corresponding ranges. Then the startup power of each non-black start-up unit is represented by the rectangular area in Figure 2 , that is:

[0092]

[0093] Combining the above formula, the objective function to be solved is expressed as:

[0094]

[0095] Among them, is the maximum active power of the unit, is the ramp rate of unit i, is the unit operation time, is the time required for unit i to prepare for ramping, is the power required for unit j to start, is the unit startup time, is all sets of units, is sets of non-black start-up units. The above formula shows that the system power generation capacity consists of two parts. The part in the first parentheses is a constant, and the second part is a function of the decision variables. Among them, it is assumed that the black start-up unit starts at the beginning of the system restoration, that is, the start time is set to zero. Therefore, by observing and ignoring the constant term, the objective function can be simplified to:

[0096]

[0097] In the equations derived in step S1031 and step S1032, the quadratic components have the same structure, that is, the product of binary decision variables and integer decision variables.

[0098] S1033. Introduce new binary variables to transform the quadratic component into the product of two binary variables:

[0099]

[0100] Among them, represents the state of the non-black start-up unit at each time slot, means that the unit is turned on on time, means that the unit is still in the shutdown state, , it can be known from the meaning that satisfies the following constraints:

[0101]

[0102] The start-up time of each non-black-start unit is the total number of its shutdown states plus 1. In addition, it is assumed that once a unit starts during the system restoration process, it will not shut down again.

[0103] S1034. Introduce a new binary variable , , convert the product of two binary variables into a binary variable:

[0104]

[0105] It can be seen from the mathematical principle that , , satisfies the following constraints:

[0106]

[0107] Please refer to Figure 1 , by taking the above steps, the unit power generation capacity function is written as:

[0108]

[0109] Classify each unit and limit it within the range corresponding to the piecewise linear function with three sets of constraints.

[0110] Please refer to Figure 2 , the unit start-up power function is expressed as:

[0111]

[0112] Limit the non-black-start units within the range corresponding to the step function with inequality constraints.

[0113] According to the above derivation, the unit start-up power can be simplified as the following constraints:

[0114]

[0115] Finally, transform this optimization problem into a mixed-integer linear programming problem. The mathematical model for solving the unit start-up sequence optimization problem by this method is as follows:

[0116]

[0117] s.t. Critical time interval constraint

[0118]

[0119] Startup power requirement constraint:

[0120]

[0121] Generator set power generation capacity constraint

[0122]

[0123]

[0124] Generator set startup power constraint

[0125]

[0126] Auxiliary decision variable constraint

[0127]

[0128]

[0129]

[0130] S2. Establish a distribution system restoration model

[0131] The optimization objective of the distribution system is to minimize the load loss during the specified system restoration period. Since the power generation and transmission system dominates during the restoration process, in the initial stage of post-disaster restoration, it should be ensured that the distributed power sources in the distribution system can provide black start power for the main units in the power generation system as much as possible, and this move requires sacrificing some loads in the distribution system. Therefore, minimizing the load loss of the disconnected loads is the restoration objective of the distribution system, expressed as:

[0132]

[0133] Among them, is the number of load nodes to be restored; is the restoration time period; is the restoration status of the load on node in the j-th time period, restored to 0, not restored to 1; is the importance degree of the load on node ; is the load loss on node .

[0134] S3. Divide different regions for coordinated restoration of power plants and the grid

[0135] Since the distributed power sources commonly put into use currently usually have characteristics such as small capacity, high uncertainty, and weak balancing ability, there are certain limitations when considering their black start capabilities. The area to be restored is divided according to the voltage level of the distribution system where it is located and the distance from the main generating units of the power generation system, and the auxiliary functions of the distributed power sources are realized in each sub-region with a small scope. In the actual operation of the power grid, major power grid companies will divide the regions in advance when formulating the restoration plan, so as to carry out parallel restoration according to the characteristics of the power grid in different regions after the disaster and improve the resilience of the power grid.

[0136] Considering the above characteristics of the distributed power sources as restoration supports, the following basic principles should be followed for the division of different regions in the coordinated restoration of power plants and the grid:

[0137] 1. There is a main generating unit with black start capability in each restoration sub-region;

[0138] The distributed power source can only provide the initial black start power to the main generating units within a certain distance range, and the main power required for restoration in the sub-region is still provided by the main generating units with black start capability in the power generation system. If there are multiple black start generating units in the sub-region, in order to avoid chaos in the restoration of the power supply path, only one is retained as the black start power source. At the same time, this division method can obtain the largest number of restoration sub-regions, thus maximizing the parallel restoration efficiency.

[0139] 2. Each restoration sub-region satisfies relative independence;

[0140] Considering the black start capability of the distributed power source, each restoration sub-region needs to contain at least one distribution system, and each distribution system belongs to only one restoration sub-region. This condition can make the output of the distributed power source more concentratedly supply a certain black start generating unit, and it is also convenient for the dispatcher to detect the power flow.

[0141] 3. The two restoration sub-regions are connected by transmission lines.

[0142] To meet the requirements of parallel restoration, the boundary between the restoration sub-regions should be divided by the circuit breakers in the transmission lines to avoid the difficulty of opening and closing operations caused by selecting transformers as the boundary.

[0143] S4. Divide different stages of the coordinated restoration of power plants and the grid

[0144] For the method of coordinated restoration of power plants and the grid in different regions and stages considering the black start capability of the distributed power source, a strategy of changing the output of the distributed power source in the distribution system at different times is adopted, and the power system restoration process is divided into multiple time periods. According to the different supporting roles and output levels of the distributed power source in different stages for the power generation and transmission systems, the coordinated restoration process of power plants and the grid is divided into the following three stages:

[0145] S401, First stage: Black start stage of the generating set

[0146] In the initial stage of post-disaster recovery, the system is in a large power outage state. At this time, quickly restoring the power generation capacity of the units in the power generation system is the most important goal. Since it takes some time for the black start units in the power generation system to provide sufficient starting power to other non-black start units, using the available distributed power generation output in the distribution system for the black start of the generating set in this stage can bring greater benefits to the entire system.

[0147] S402, Second stage: Skeleton network reconstruction stage

[0148] In the middle stage of post-disaster recovery, some non-black start units in the power generation system can output power, and the skeleton network is initially built. The transmission grid already has sufficient unit starting power, and the power that the distributed units can provide is relatively small compared to the main units in the power generation system. Therefore, using part of the distributed power generation output for the recovery of the power transmission and distribution system and part for the recovery of important loads in the distribution system in this stage can improve the overall recovery ability of the power system.

[0149] S403, Third stage: Important load recovery stage

[0150] In the later stage of post-disaster recovery, the main units in the power transmission and distribution system have all been started and participated in grid connection. The system is in a top-down recovery process, and the power generation system provides most of the recovery power. At this time, all distributed power generation should be used for the recovery of loads in the distribution system to play a role in nearby assistance and accelerating load recovery.

[0151] S5. Establish a multi-region and multi-stage plant-grid coordinated recovery model

[0152] During the entire power system recovery stage, by introducing a penalty function to represent the different roles of distributed power generation in the three stages, each divided recovery sub-region is optimized, so as to achieve the purpose of sub-region and sub-stage, and plant-grid coordination.

[0153] The optimized coordinated recovery model is expressed as:

[0154]

[0155] Among them, is the plant-grid coordinated recovery penalty function, which represents the contribution degree of distributed power generation in the distribution system to the power transmission and distribution system. According to the above division of different recovery time periods, this penalty function has different values. In the black start stage of the generating set, there is ; in the skeleton network reconstruction stage, there is ; in the important load recovery stage, there is According to the changes of the penalty function during the restoration process, implement coordinated restoration optimization of the power plant and grid in different regions and stages, and formulate restoration strategies.

[0156] S6. Based on the multi-region and multi-stage coordinated restoration model in step S5, formulate a coordinated restoration strategy for the power plant and grid in different regions and stages.

[0157] Finally, by solving the multi-region and multi-stage coordinated restoration model established in step S5, obtain the restoration strategies for each stage of different restoration sub-regions. According to the objective functions of the power generation and transmission system and the distribution system, use the hierarchical sequence method to focus on the main problems in turn, divide the restoration process into multiple stages for calculation. In each restoration period, first update the penalty function according to the status of the units in the power generation system, determine the support lease of distributed power sources, then optimize according to the objective function and constraints, and finally update the available power according to the unit restoration results and restore the load; ultimately, an optimized strategy for the unit startup sequence considering the backbone network reconstruction process and a load restoration optimization strategy based on the greedy algorithm can be obtained, providing a complete and reliable decision-making reference for post-disaster restoration for power system operators.

[0158] In another embodiment of the present invention, a multi-region and multi-stage coordinated restoration system for the power plant and grid is provided. This system can be used to implement the above multi-region and multi-stage coordinated restoration method. Specifically, the multi-region and multi-stage coordinated restoration system for the power plant and grid includes a conversion module, a target module, a division module, a change module, and a restoration module.

[0159] Among them, the conversion module converts the objective function and constraints into a mixed-integer linear programming problem, and establishes a power generation and transmission system restoration model;

[0160] The target module takes the minimum loss of the disconnected load as the restoration target and establishes a distribution system restoration model;

[0161] The division module divides the area to be restored according to the voltage level of the distribution system where it is located and the distance from the main power generation units of the power generation system;

[0162] The change module adopts a strategy of changing the output of distributed power sources in the distribution system in different time periods, and divides the coordinated restoration stage of the power plant and grid into a generator black start stage, a backbone network reconstruction stage, and an important load restoration stage;

[0163] The restoration module synthesizes the power generation and transmission system restoration model established by the conversion module and the distribution system restoration model established by the target module to form a power system restoration model. According to the division results of the area to be restored in the division module, introduce a penalty function to optimize the generator black start stage, backbone network reconstruction stage, and important load restoration stage divided by the change module, and establish a multi-region and multi-stage coordinated restoration model for the power plant and grid.

[0164] In summary, for a multi-region and multi-stage plant-grid coordinated restoration method and system according to the present invention, a method of coordinated restoration by regions and stages is adopted to model the power system restoration problem. In the power generation and transmission system, maximizing the power generation of units under the reconstruction of the backbone network is considered; in the distribution system containing distributed power sources (including new energy and energy storage), minimizing the load loss is considered. By changing the plant-grid coordinated restoration penalty function to represent the contribution degree of distributed power sources in the distribution system to the power generation and transmission system at different time periods, the time-sharing support of the black start capability of distributed power sources for power system restoration is realized. The time-sharing plant-grid coordinated restoration method of the present invention can be used as an important auxiliary tool in the post-disaster restoration process of the power system, providing relatively comprehensive decision-making guidance for power system operators and providing a reference for the identification of key nodes.

[0165] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0166] The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for realizing the functions specified in Figure 1 one or more of the processes Figure 1 or multiple processes and / or blocks

[0167] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device, and the instruction device realizes the functions specified in Figure 1 one or more of the processes Figure 1 or multiple processes and / or blocks

[0168] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus, so that a series of operation steps are executed on the computer or other programmable apparatus to produce a computer-implemented process, thereby providing instructions for implementing the functions specified in one process or a plurality of processes and / or blocks Figure 1 one process or a plurality of processes and / or blocks Figure 1 steps of the functions specified in one block or a plurality of blocks.

[0169] The above is only to illustrate the technical idea of the present invention and should not be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A multi-region and multi-stage coordinated restoration method for power plants and grids, characterized in that, It includes the following steps: S1. Convert the objective function and constraints into a mixed-integer linear programming problem, and establish a power generation and transmission system restoration model. The objective function of the power generation and transmission system restoration model is: Among them, is the maximum active power of the unit, is the ramp rate of unit i, is the operation time of the unit, is the time required for unit i to prepare for ramping, is the power required for the start-up of unit j, is the start-up moment of the unit, is all the set of units, is the set of non-black-start units; S2. Establish a distribution system restoration model with the goal of minimizing the load loss of the disconnected loads; S3. Divide the area to be restored according to the voltage level of the distribution system where it is located and the distance from the main generating units of the power generation system; S4. Adopt a strategy of changing the output of distributed power sources in the distribution system in different time periods, and divide the plant-network coordinated restoration stage into a generator black start stage, a backbone network reconstruction stage, and an important load restoration stage; S5. Integrate the power generation and transmission system restoration model established in step S1 and the distribution system restoration model established in step S2 to form a power system restoration model. According to the result of the division of the area to be restored in step S3, introduce a penalty function to optimize the generator black start stage, backbone network reconstruction stage, and important load restoration stage divided in step S4, and establish a multi-region and multi-stage plant-network coordinated restoration model. The multi-region and multi-stage plant-network coordinated restoration model is specifically: Among them, is the factory-grid coordination restoration penalty function, is the objective function of the power generation and transmission system restoration model, is the objective function of the distribution system restoration model; S6. Solve the multi-region and multi-stage plant-network coordinated restoration model established in step S5, formulate a plant-network coordinated restoration strategy for different regions and stages, and achieve multi-region and multi-stage plant-network coordinated restoration.

2. The multi-region multi-stage plant-grid coordinated restoration method according to claim 1, wherein In step S1, the constraints of the power generation and transmission system restoration model are: Critical time interval constraint Startup power requirement constraint: Generator capacity constraint Generator startup power constraint Auxiliary decision variable constraint Among them, , and are linear decision variables, and are binary decision variables, is the set of non-black-start units, is the non-black-start unit at each time slot, is the minimum value of the unit start time, is the unit start time, is the maximum value of the unit start time, is the number of the j-th unit, is the ramp rate of unit g, is the current time, is a binary decision variable, is the power required for unit g to start, is the time required for unit g to prepare for ramping, is the unit operation time, is the maximum active power of unit g, is an auxiliary decision variable, is an auxiliary decision variable, is a binary decision variable, is a binary decision variable, .

3. The multi-region and multi-stage plant-network coordinated restoration method according to claim 1, wherein In step S2, the specific goal of the distribution system restoration is: Among them, is the number of load nodes to be restored; is the restoration period; is the restoration status of the load on node at the j-th period; is the importance level of the load on node ; is the load loss on node .

4. The multi-region multi-stage plant-grid coordinated restoration method according to claim 1, characterized in that In step S3, the division conditions are specifically: There is a main generating unit with black start capability in each restoration sub-region; each restoration sub-region contains at least one distribution system, and each distribution system belongs to only one restoration sub-region; two restoration sub-regions are connected by transmission lines.

5. The multi-region and multi-stage plant-network coordinated restoration method according to claim 1, characterized in that, In step S4, in the generator black start stage, the available output of distributed power sources in the distribution system is used for the black start of generators; in the backbone network reconstruction stage, part of the output of distributed power sources is used for the restoration of the power generation and transmission system, and part is used for the restoration of important loads in the distribution system; in the important load restoration stage, all the output of distributed power sources is used for the restoration of loads in the distribution system.

6. The multi-region and multi-stage plant-grid coordinated restoration method according to claim 1, wherein In step S5, during the black start phase of the generating set, ; during the backbone network reconstruction phase, ; During the important load restoration phase, .

7. The multi-region and multi-stage plant-network coordinated restoration method according to claim 1, wherein Step S5 is specifically: According to the objective functions of the power generation and transmission system and the distribution system, use the hierarchical sequence method to focus on the main problems in turn, divide the restoration process into multiple stages for calculation; in each restoration time period, first update the penalty function according to the status of the generating units in the power generation system, determine the support lease of distributed power sources, then optimize according to the objective function and constraints, and finally update the available power according to the generator restoration result and restore the load; finally, obtain an optimized strategy for the generator startup sequence considering the backbone network reconstruction process and a load restoration optimization strategy based on the greedy algorithm to achieve post-disaster restoration decision-making.

8. A multi-region and multi-stage plant-network coordinated restoration system, characterized in that, It includes: A conversion module that converts the objective function and constraints into a mixed-integer linear programming problem and establishes a power generation and transmission system restoration model. The objective function of the power generation and transmission system restoration model is: Among them, is the maximum active power of the unit, is the ramp rate of unit i, is the operating time of the unit, is the time required for unit i to prepare for ramping, is the power required for the startup of unit j, is the startup time of the unit, is all the set of [[number]] units, is the set of [[number]] non-black-start units; An objective module that establishes a distribution system restoration model with the goal of minimizing the load loss of the disconnected loads; A division module divides the area to be restored according to the voltage level of the distribution system and the distance from the main generating units of the power generation system; The module is modified to adopt a strategy of changing the output of distributed power sources in the distribution system in different time periods, dividing the plant-grid coordinated recovery phase into the generator black start phase, the skeleton network reconstruction phase, and the important load recovery phase; The restoration module integrates the power transmission system restoration model established by the conversion module and the distribution system restoration model established by the target module to form a power system restoration model. According to the results of the division of the areas to be restored in the division module, a penalty function is introduced to optimize the black start phase of the generator set, the skeleton network reconstruction phase, and the important load restoration phase of the changed module division. A multi-region and multi-stage plant-grid coordinated restoration model is established, and the established multi-region and multi-stage plant-grid coordinated restoration model is solved. A plant-grid coordinated restoration strategy for each region and stage is formulated to achieve multi-region and multi-stage plant-grid coordinated restoration. The multi-region and multi-stage plant-grid coordinated restoration model is specifically as follows: Among them, is the factory-grid coordination restoration penalty function, is the objective function of the power generation and transmission system restoration model, is the objective function of the distribution system restoration model.

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