1. The method for evaluating the flexibility of the comprehensive energy system is characterized by comprising the following steps of:

1) constructing a framework of a comprehensive energy system flexibility index evaluation system;

2) according to the framework of the comprehensive energy system flexibility index evaluation system, qualitative and quantitative evaluation of the comprehensive energy system flexibility is realized by combining an analytic hierarchy process and a fuzzy evaluation method.

2. The method for evaluating the flexibility of the integrated energy system according to claim 1, wherein in the step 1), the integrated energy system flexibility evaluation framework comprises a target layer, a criterion layer and a specific index layer.

3. The method according to claim 2, wherein the target layer is an evaluation index of the flexibility of the integrated energy system, and the criterion layer corresponds to four links of source, grid, load and storage of the integrated energy system, and specifically includes six levels of energy supply output, high-proportion renewable energy consumption, energy network interconnection, load demand, energy storage and system flexibility capability, wherein the energy supply output and the high-proportion renewable energy consumption correspond to the source side of the integrated energy system, the energy network interconnection corresponds to the grid side of the integrated energy system, the load demand corresponds to the load side of the integrated energy system, the energy storage corresponds to the energy storage side of the integrated energy system, and the system flexibility capability is quantitatively evaluated from the system level.

4. The method according to claim 3, wherein the specific indexes of the energy supply output criterion layer comprise a system inertial permeability and a fast frequency response/fast temperature response, and the expression of the system inertial permeability is as follows:

5. the method for evaluating the flexibility of the integrated energy system according to claim 4, wherein the specific indexes of the high-proportion renewable energy consumption criterion layer comprise a climbing rate and a minimum load satisfaction degree, and the corresponding expressions are as follows:

6. the method for evaluating the flexibility of the integrated energy system according to claim 4, wherein the specific indexes of the energy network interconnection layer comprise energy interconnection and regional scheduling capabilities, and the expression of the energy interconnection and regional scheduling capabilities is as follows:

7. the method for evaluating the flexibility of the integrated energy system according to claim 4, wherein the specific indexes of the load demand layer comprise demand response occupation ratio and electric vehicle ordered charging and discharging management, and the corresponding expressions are as follows:

8. the method for evaluating flexibility of the integrated energy system according to claim 4, wherein the specific indexes of the energy storage layer comprise an energy storage occupation ratio, and when the energy storage device serves as a source side, the expression is as follows:

when the energy storage device is used as a load side, the expression is as follows:

9. the method for evaluating the flexibility of the integrated energy system according to claim 4, wherein the specific indexes of the system flexibility performance layer comprise an up-regulation flexibility adequacy, a down-regulation flexibility adequacy, an up-regulation flexibility inadequacy and a down-regulation flexibility inadequacy, and the corresponding expressions are as follows:

10. the method for evaluating the flexibility of the integrated energy system according to claim 1, wherein the step 2) is specifically as follows:

the method comprises the steps of determining the weight of a comprehensive energy system flexibility evaluation index by combining an expert scoring method and an analytic hierarchy process, comprehensively evaluating the flexibility of the comprehensive energy system by adopting a multi-level fuzzy comprehensive evaluation model, determining a comment set V which is { very small and flexible, general and flexible, large and flexible, very flexible } to express the flexibility of different degrees, determining a membership matrix according to an expert scoring result, and further realizing the comprehensive energy system flexibility evaluation combining qualitative evaluation and quantitative evaluation, wherein the specific evaluation standard is as follows:

Background

Under the 'double carbon' vision of carbon peak reaching, carbon neutralization and 'novel power system' background mainly based on new energy, the comprehensive energy system of multi-energy fusion, coordination and complementation and cascade utilization is rapidly developed. Due to the fact that the consumption proportion of uncertain renewable energy sources is increased and load fluctuation factors, a comprehensive energy source system faces the challenges of production-demand imbalance and economic operation, and the flexibility of the system becomes the key of safety, reliability and economic operation of the system, so quantitative evaluation on the flexibility of the comprehensive energy source system is urgently needed.

At present, most of the existing flexibility evaluation indexes are established aiming at the flexibility of the power system, and a part of deep thought has been given in the power system, but the research on the flexibility evaluation indexes of the comprehensive energy system is still in a starting stage, an index system capable of accurately reflecting the flexibility resource evaluation condition of the comprehensive energy system is lacked, and the practical situation of the system cannot be guided. In the aspect of comprehensive evaluation index research of a comprehensive energy system, the research on network side system operation optimization and energy efficiency evaluation is mature, but the research on a source network charge storage integrated system of the comprehensive energy system is less, the research on the flexibility resource evaluation index of the source network charge storage integrated system is less, and for the comprehensive energy system, the flexibility resource not only exists on an energy supply side, but also exists in each link of energy supply, energy transmission, energy consumption and energy storage of the system, and the flexibility resource needs to be fully excavated to provide a larger flexibility space for the system. Most of evaluation indexes of the existing flexible index system are qualitative indexes, the documents for setting the quantitative indexes are few, and in order to make the conclusion of qualitative analysis convincing, the quantitative indexes need to be quantized, so that the quantitative indexes need to be set for evaluation; the single evaluation method has respective limitations, is difficult to comprehensively and comprehensively reflect the comprehensive evaluation of the whole system, and needs several methods to combine the disadvantages of evading methods for comprehensive and effective evaluation.

At present, most of the existing patent technologies related to the flexibility evaluation indexes are researches on the flexibility indexes of the power system, but the patent technologies related to the flexibility evaluation indexes of the comprehensive energy system are few, and an index system capable of accurately reflecting the flexibility resource evaluation condition in the comprehensive energy system is lacked; the patent of some research comprehensive energy system flexibility evaluation indexes focuses on one link of energy production, transportation, storage, utilization and the like in the system, and a complete system flexibility evaluation index system cannot be constructed because systematic research flexibility evaluation indexes do not exist. Meanwhile, in the existing patents related to the evaluation method of the index system, most of the patents for constructing the index system by using a single method are more, and the single evaluation method has respective disadvantages.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a comprehensive energy system flexibility evaluation method, which comprises a local flexibility index system and a system level flexibility index system in the comprehensive energy flexibility evaluation, wherein the local flexibility index system is used for evaluating indexes of each flexibility resource in the system, and the system level flexibility index system is mainly used for evaluating the comprehensive indexes of the flexibility of the whole system. In the invention, only the construction and evaluation of a system level flexibility index system are involved.

The purpose of the invention can be realized by the following technical scheme:

a comprehensive energy system flexibility evaluation method comprises the following steps:

1) constructing a framework of a comprehensive energy system flexibility index evaluation system;

2) according to the framework of the comprehensive energy system flexibility index evaluation system, qualitative and quantitative evaluation of the comprehensive energy system flexibility is realized by combining an analytic hierarchy process and a fuzzy evaluation method.

In the step 1), the comprehensive energy system flexibility evaluation framework comprises a target layer, a criterion layer and a specific index layer.

The target layer is an evaluation index of the flexibility of the comprehensive energy system, the criterion layer corresponds to four links of source, network, charge and storage of the comprehensive energy system respectively, and specifically comprises six levels of energy supply output, high-proportion renewable energy consumption, energy network interconnection, load demand, energy storage and system flexibility capability, wherein the energy supply output and the high-proportion renewable energy consumption correspond to the source side of the comprehensive energy system, the energy network interconnection corresponds to the network side of the comprehensive energy system, the load demand corresponds to the load side of the comprehensive energy system, the energy storage corresponds to the energy storage side of the comprehensive energy system, and the system flexibility capability is quantitatively evaluated from the system level.

The specific indexes of the energy supply output criterion layer comprise system inertia permeability and rapid frequency response/rapid temperature response, and the expression of the system inertia permeability is as follows:

the specific indexes of the high-proportion renewable energy consumption criterion layer comprise a climbing rate and a minimum load satisfaction degree, and the corresponding expressions are as follows:

the specific indexes of the energy network interconnection layer comprise energy interconnection and regional scheduling capability, and the expression of the energy interconnection and regional scheduling capability is as follows:

the specific indexes of the load demand layer comprise demand response occupation ratio and electric vehicle ordered charging and discharging management, and the corresponding expressions are as follows:

the specific indexes of the energy storage layer comprise an energy storage occupation ratio, and when the energy storage device is used as a source side, the expression is as follows:

when the energy storage device is used as a load side, the expression is as follows:

the specific indexes of the system flexibility performance layer comprise an up-regulation flexibility adequacy, a down-regulation flexibility adequacy, an up-regulation flexibility deficiency and a down-regulation flexibility deficiency, and the corresponding expressions are as follows:

the step 2) is specifically as follows:

the method comprises the steps of determining the weight of a comprehensive energy system flexibility evaluation index by combining an expert scoring method and an analytic hierarchy process, comprehensively evaluating the flexibility of the comprehensive energy system by adopting a multi-level fuzzy comprehensive evaluation model, determining a comment set V which is { very small and flexible, general and flexible, large and flexible, very flexible } to express the flexibility of different degrees, determining a membership matrix according to an expert scoring result, and further realizing the comprehensive energy system flexibility evaluation combining qualitative evaluation and quantitative evaluation, wherein the specific evaluation standard is as follows:

compared with the prior art, the invention has the following advantages:

the invention aims to provide a method for constructing a comprehensive energy system flexibility evaluation index system, which aims to solve the problem of evaluation of comprehensive energy system level flexibility and realize safe, reliable and economic operation in a comprehensive energy system, and has the following characteristics and advantages:

firstly, a flexibility evaluation index system is expanded from a power system to a comprehensive energy system. At present, the evaluation indexes of the flexibility are partially considered in the power system, but the research on the evaluation indexes of the flexibility of the comprehensive energy system is still in a starting stage, an index system capable of accurately reflecting the evaluation condition of the flexibility of the comprehensive energy system is lacked, and the practical situation can not be guided. The method is based on the comprehensive energy system, and the flexibility evaluation index of the comprehensive energy system is constructed.

Secondly, an evaluation index system of a comprehensive energy system level is constructed, and the evaluation is carried out from the whole system level by considering the flexibility of each side of the comprehensive energy system, namely source-network-load-storage, and is respectively defined as five levels of energy supply output, high-proportion renewable energy consumption, energy network interconnection, load demand and energy storage to correspond to four links of source network load storage in the comprehensive energy system. Meanwhile, the system flexibility is evaluated and quantified, and a system flexibility capability criterion layer is provided. Therefore, specific evaluation indexes are sequentially set from six different levels, and the flexibility of the comprehensive energy system is evaluated.

And thirdly, the flexibility of the comprehensive energy system is closely related to economy, reliability and safety. Therefore, in the construction of the index, the minimum load satisfaction index is provided aiming at the economic operation of a high-proportion renewable energy system, and the change of the matching cost between the renewable energy output and the load is reflected. In consideration of the reliability of the system, the indexes of the flexibility of up/down regulation and the flexibility of up/down regulation are insufficient, so that the flexibility resource abundance is embodied. Meanwhile, aiming at the safe and stable operation of the system, an inertial permeability index and a climbing rate index of the system are provided.

And fourthly, further evaluating the constructed index system by adopting an evaluation method combining an Analytic Hierarchy Process (AHP) and a fuzzy evaluation method (FCE). The single evaluation method has respective limitations, and the comprehensive evaluation of the whole system is difficult to be reflected integrally and comprehensively. Because the quantification is difficult to be carried out when flexible resources are evaluated, the flexible resources can only be described through the comments with fuzzy boundaries. However, in order to persuade the conclusion of qualitative analysis, apply the qualitative analysis to practice better and guide the practical development situation, it is necessary to quantify the qualitative analysis, so that the qualitative evaluation is converted into quantitative evaluation by combining with fuzzy evaluation (FCE). Fuzzy Comprehensive Evaluation (FCE) is a method for converting qualitative evaluation into quantitative evaluation, can well solve the problems of fuzziness and difficulty in quantification, and is suitable for solving various non-deterministic problems. One of the preconditions of FCE calculation is to determine the weight of each evaluation index, but for complex problems, for example, many evaluation indexes exist in an index system and influence relationship exists between them, it is difficult to directly give the weight of each evaluation index, and this problem is the excellence of the Analytic Hierarchy Process (AHP). In AHP, through the decomposition to the problem, decompose the complicated problem into a plurality of subproblems, and give the decision data through the form of two-by-two comparison, give the weight finally, thus has solved the problem that complicated evaluation index weight in FCE confirms.

Drawings

Fig. 1 is a flow chart of construction of an integrated energy system flexibility evaluation index system.

FIG. 2 is a flow chart of the evaluation method of the present invention.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments.

The method constructs an index system framework for evaluating the flexibility of the comprehensive energy system, selects indexes capable of evaluating the flexibility of different links of 'source network charge storage' from the whole comprehensive energy system, specifically comprises a target layer, a standard layer and a specific index layer, and further evaluates the constructed index system by adopting a method of combining an Analytic Hierarchy Process (AHP) and a fuzzy evaluation method (FCE). The basic principle of an analytic hierarchy process is adopted, a hierarchical structure is divided, the influence degree of each index on flexibility is scored, and the qualitative index membership degree is determined; in order to make the conclusion of qualitative analysis convincing, the qualitative analysis is quantified, and after the membership degree of the qualitative index is defined, the membership degree of the quantitative index is calculated by adopting a fuzzy evaluation method, so that the combination of qualitative evaluation and quantitative evaluation of the index is realized.

The invention provides a comprehensive energy system flexibility evaluation method, which comprises two parts, namely, a system level flexibility index system different from the existing index system is constructed, and evaluation is carried out according to the index system, and the method mainly comprises the following steps:

1. constructing a flexibility comprehensive evaluation index system framework of a comprehensive energy system level, wherein the flexibility comprehensive evaluation index system framework specifically comprises a target layer (A), a criterion layer (B) and a specific index layer (C), and is shown in FIG. 1;

taking the flexibility evaluation of the comprehensive energy system as a target layer (A) in a system-level flexibility comprehensive evaluation index system framework;

the criterion layer (B) specifically comprises six levels of energy supply output, high-proportion renewable energy consumption, energy network interconnection, load demand, energy storage and system flexibility, and the six levels correspond to four links of 'source network charge storage' of the comprehensive energy system. The two criterion layers of energy supply output and high-proportion renewable energy consumption are used for reflecting the flexible resource condition of the source side; the energy network interconnection is a standard layer of flexible resources on the network side; the load demand is the standard layer from the load side; the energy storage rule layer reflects the condition of flexible resources of the storage side; the five standard levels correspond to four links of 'source network charge storage' of the comprehensive energy system, and the flexibility capability of the system of the sixth standard level is quantitatively evaluated from the system level, so that the flexibility of the 'source network charge storage' integrated comprehensive energy system is reflected.

The specific index layer (C) is described as follows:

1) the specific indexes of the energy supply output criterion layer comprise two indexes, namely system inertia permeability and rapid frequency response/rapid temperature response;

the system inertial permeability refers to the capability of the comprehensive inertia of the system after the factors such as the electrical inertia and the thermal inertia of the energy supply side in the comprehensive energy system are combined, and the elasticity of the system to the suddenly generated change is used for relieving the instant imbalance of the energy supply and demand of the system and reflecting the indexes of the flexibility and the stability of the system. In the research of the power system, the inertia permeability is more, the inertia does not exist in the power system, and the thermodynamic system also has the characteristic of inertia, so that the invention expands the inertia permeability index of the system, so that the inertia permeability index is not limited to the power system, and the specific formula is as follows:

the quick frequency response/quick temperature response is to reduce the influence of frequency change on the quality of electric energy in the power system, and the quick temperature response is to reduce the fluctuation of the thermal quality in the thermal system and improve the utilization efficiency of the energy system, and the index reflects the quick response capability of the electric/heat (cold) quality adjustment of the comprehensive energy system.

2) The specific indexes of the high-proportion renewable energy consumption criterion layer comprise two indexes, namely the climbing speed and the minimum load satisfaction, and the strategic goals of guaranteeing energy supply, promoting the green and low-carbon development of energy and realizing carbon peak-to-peak carbon neutralization are achieved, so that the development of the renewable energy with high proportion, high quality, low cost and marketization is promoted to become the key point of the development of the comprehensive energy system. When the renewable energy consumption level is improved, in order to ensure the stable operation of the comprehensive energy system, the flexible adjustment capability of the comprehensive system needs to be enhanced, so that a high-proportion renewable energy consumption index is set in an index system.

The climbing speed refers to the load ascending and descending capacity of the system and is an important parameter for normal operation of the system. When high-proportion renewable energy permeates, the power plant/thermal power plant, cogeneration and other units need to continuously adjust the output of the forms of electricity, heat, cold and the like (called load following) at a higher speed, the safe operation of a comprehensive energy system is guaranteed, and the index for flexibly adjusting the proportion of a power supply is reflected, wherein the specific formula is as follows:

and secondly, the minimum load satisfaction is the ratio of the minimum net load of the system to the total energy supply amount of the system, and in order to solve the cost generated by the irrelevance of the output of the renewable energy sources and the load, the operation cost of the system is reduced when the high-proportion renewable energy sources of the system are consumed. The index combines the calculation of economic cost to provide guidance for the economy of the system optimization operation, and the specific formula is as follows:

3) the specific indexes of the energy network interconnection layer comprise energy interconnection and regional scheduling capabilities, the indexes refer to interconnection and scheduling of energy networks in the same region or different regions, accordingly, energy balance such as electric heat in each region can be achieved, energy complementation such as electric heat among different regions can be achieved, interconnection of different systems not only allows the system to share flexibility in a larger geographical region, system cost is reduced, but also energy supply sides and energy utilization sides of other regions can be called simultaneously in originally independent regions, and diversity of the energy supply sides and the energy utilization sides is increased. The index reflects the flexibility of the multi-energy interconnection, intercommunication, complementation and interchange of the energy supply and demand system. Under the large background of energy internet development, the index is provided with important practical significance, and the specific formula is as follows:

4) the specific indexes of the load demand layer comprise two indexes, namely demand response occupation ratio and orderly charging and discharging management of the electric automobile. The load side index not only considers the change of demand response guided by current human factors, but also refers to the concept of the electric automobile, and the electric automobile can be used as a flexible resource, and the flexible adjustment effect on an energy system is gradually highlighted, so that the index of the ordered charging and discharging management of the electric automobile is provided, and the current hot tide demand of the electric automobile is met.

Firstly, the occupation ratio of demand response refers to the ratio of the demand response capacity and the energy utilization capacity of the system, the comprehensive energy demand side response guides a terminal user to adjust the energy utilization habit or convert the energy source through a price mechanism or an incentive measure, the load transfer/reduction and the energy utilization substitution are realized, the operation of the whole system is more efficient, the index reflects the adjustability of the system user participating in the demand response, and the specific formula is as follows:

second, the orderly charge and discharge management of the electric automobile means that under the premise of meeting the charge and discharge requirements of the electric automobile, the electric automobile is guided and controlled to be charged and discharged orderly by using economic means and technical measures, the electric automobile can be used as a load side flexibility resource when being charged, the load transfer/reduction is realized, the peak-valley difference of the load of the power grid is adjusted, the electric automobile can be used as a power supply side flexibility resource when being discharged, the electric automobile can be used as an effective supplement of a power system, the frequency adjustment of the power grid is participated, and the running stability of the power grid is improved, and the specific formula measures:

it should be noted that: at present, flexible adjustment of the energy supply capacity of the electric automobile participating system is not considered for technical reasons, but with the increasing maturity of technologies such as V2G and the like, the flexible adjustment effect of the electric automobile on an energy system is gradually highlighted.

5) The specific index of the energy storage layer comprises the energy storage occupation ratio, and the index refers to the capacity space occupation ratio which can be provided by different energy storage forms. The energy storage technology can store the surplus energy of the system during the load valley, and can provide considerable energy to the system during the peak, when the energy storage equipment is used as the load side, the energy storage equipment can compensate the load fluctuation, improve the operation stability of the system, and reflect the energy storage capacity of the system as the load side, the specific formula is shown as the following formula (7), when the energy storage equipment is used as the source side, the output fluctuation of the renewable energy can be smoothed, the available energy capacity of the system is provided, and the available energy quality is improved, and the specific formula is shown as the following formula (8):

6) the specific indexes of the system flexibility performance layer comprise four indexes: the up-regulation flexibility is sufficient, the down-regulation flexibility is sufficient, the up-regulation flexibility is insufficient, and the down-regulation flexibility is insufficient.

When the flexibility of the overall operation of the comprehensive energy system is evaluated and quantified under a certain time scale, the situation of 'short-time large quantity' frequently occurs in consideration of the shortage of flexible resources. The method comprises the following steps of providing the flexibility allowance of up/down regulation and the flexibility insufficiency of up/down regulation on the basis of the time index with sufficient flexibility and insufficient flexibility to evaluate the overall flexibility of the source network and load storage integrated system, wherein a specific index formula is as follows:

specific evaluation indexes are shown in table 1:

TABLE 1 evaluation index Table

2. The invention further evaluates the constructed index system, adopts a method of combining an analytic hierarchy process and a fuzzy evaluation method, and determines the weight of the flexibility evaluation index of the comprehensive energy system by utilizing a mode of combining an expert scoring method and the analytic hierarchy process, and the qualitative analysis conclusion is necessary to be quantized in order to be convincing. Therefore, after the qualitative index weight is determined, a multilevel fuzzy comprehensive evaluation model is adopted to comprehensively evaluate the flexibility of the comprehensive energy system, and a comment set V is determined.

Examples

The flow of the evaluation method for the comprehensive energy system flexibility index system provided by the invention is shown in fig. 2, and the specific implementation mode is further described in detail below by combining the evaluation flow of one layer of indexes and the attached drawing. The fuzzy analytic hierarchy process evaluation is carried out by taking a criterion layer of energy supply output comprising two indexes of system inertia permeability and rapid frequency response/rapid temperature response as an example.

(1) Constructing B according to the expert rating condition₁-C_1iJudgment matrix B₁And the weight determination of each sub-index, as shown in table 2:

TABLE 2 decision matrix and sub-index weights

And (3) checking consistency: when the judgment matrix has complete consistency, if and only if the consistency of the judgment matrix passes the inspection, otherwise, the judgment matrix is readjusted, and finally the inspection is passed.

(2) Before evaluating the membership degree of the flexibility evaluation index of the comprehensive energy system, an evaluation set V, namely a set of evaluations of an evaluation object by an evaluator, needs to be determined, then primary fuzzy evaluation and secondary fuzzy evaluation are carried out, and finally, an evaluation result is analyzed. The invention divides the comment into 5 grades which are respectively { very small, flexible, general, large and flexible }, designs the corresponding questionnaire survey, invites experts in the related field of comprehensive energy system flexibility evaluation to score each index, and obtains the fuzzy evaluation 2 x 5 order matrix R of the energy supply output layer₁As shown in table 3.

TABLE 3 fuzzy evaluation matrix R₁

Selecting weighted average operator to carry out fuzzy operation to obtain comprehensive evaluation vector V_iVery small agility v₁Small flexibility v₂General flexibility v₃Greater flexibility v₄Very flexible v₅In which v is_iIs a weight value.

Similarly, the indexes of each level are evaluated according to the constructed index system, the space is limited, the indexes are not expanded in detail, and finally the evaluation criteria of the evaluation indexes are shown in table 4:

TABLE 4 index evaluation criteria