Pumped storage operation evaluation method considering multi-dimensional benefits of novel power system
By introducing a comprehensive scoring model based on multi-dimensional indicators, the problem of incompleteness in existing pumped storage evaluation methods is solved, enabling a comprehensive and accurate assessment of pumped storage in new power systems and improving the system's flexibility and stability.
Patent Information
- Application Number
- CN202511227436.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-29
- Publication Date
- 2025-12-05
AI Technical Summary
Existing evaluation methods for pumped storage cannot fully reflect its multiple functional benefits in new power systems, and are easily affected by the selection of economic indicators, leading to inaccurate and incomplete evaluation results.
A multi-dimensional evaluation method is adopted, including indicators of economy, low carbon emissions, flexibility and reliability. A comprehensive scoring calculation model is constructed for evaluation by quantifying indicators such as replacement of thermal power capacity, saving power generation, increasing renewable energy power, reducing carbon emissions, available frequency regulation capacity, available reactive power, available moment of inertia and expected energy storage value.
It enables accurate, reliable and comprehensive evaluation of pumped storage, improves the assessment of new energy consumption and system stability, optimizes resource allocation and fault response capabilities, and enhances the uniformity and reliability of the evaluation.
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Figure CN121073293A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of pumped storage operation evaluation, in particular to a pumped storage operation evaluation method considering multi-dimensional benefits of a new power system. BACKGROUND
[0002] With the gradual increase of new energy in the new power system, it is urgent to improve the system flexibility to cope with the supply and demand relationship of fluctuation. Among them, pumped storage as a flexible adjustment resource, has mature technology, economic reliability and large-scale development conditions.
[0003] In order to evaluate the good and bad of pumped storage power station more systematically and comprehensively, the current research usually adopts comprehensive evaluation method to measure the operation benefit of pumped storage power station. But the indexes in the current research are mostly only suitable for the traditional power system dominated by thermal power, and cannot reflect the benefits of pumped storage serving the construction of new power system. The specific indexes of pumped storage usually focus on the peak regulation function of pumped storage, and cannot comprehensively and completely reflect the comprehensive benefits generated by the superposition of multiple functions of pumped storage. Or the evaluation system is too single, and the method of quantifying the benefits in currency form is easy to ignore the potential benefits of pumped storage, and the quantification result is easy to be affected by the selection of related economic indexes.
[0004] Therefore, it is necessary to design an evaluation method for pumped storage to realize accurate, reliable and comprehensive evaluation of pumped storage. SUMMARY
[0005] The purpose of the present application is to provide a pumped storage operation evaluation method considering multi-dimensional benefits of a new power system, which realizes accurate, reliable and comprehensive evaluation of pumped storage.
[0006] The present application is realized by the following technical scheme: The pumped storage operation evaluation method considering multi-dimensional benefits of a new power system comprises the following steps: Obtain economic dimension indexes of pumped storage operation effect, the economic dimension indexes including alternative thermal power capacity index and power saving index; Obtain low-carbon dimension indexes of pumped storage operation effect, the low-carbon dimension indexes including improved new energy power and reduced carbon emission; Obtain flexibility dimension indexes of pumped storage operation effect, the flexibility dimension indexes including available frequency modulation capacity and available reactive power; Obtain reliability dimension indexes of pumped storage operation effect, the reliability dimension indexes including available moment of inertia and expected energy storage value; According to the economic dimension indexes, the low-carbon dimension indexes, the flexibility dimension indexes and the reliability dimension indexes, the comprehensive evaluation result is obtained based on a comprehensive score calculation model.
[0007] Preferably, the method for obtaining the alternative thermal power capacity indicator is: comparing the operation capacity of the thermal power unit of the system with and without pumped storage, and quantifying the alternative thermal power capacity indicator of the pumped storage : ; ; wherein, is the thermal power operation capacity of the power system in day d in the operation scenario s, DY is the total number of days in the evaluation year, and s represents the scenario type, s is 1 when the system has pumped storage in the operation scenario, and s is 0 when the system has no pumped storage in the operation scenario, represents the start-stop state of the thermal power unit g in the t period of day d in the scenario s, is 1 when it is running, is 0 when it is stopped, is the installed capacity of the thermal power unit g in the scenario s, is the total number of thermal power units.
[0008] Preferably, the method for obtaining the power generation saving indicator is: comparing the operation cost of the thermal power unit of the system with and without pumped storage, and quantifying the power generation saving indicator of the pumped storage , wherein the operation cost includes the start-up cost and the variable cost: ; ; wherein, is the total coal consumption of the system in the t period of day d in the scenario s, is the single start-up cost of the thermal power unit g, is the active power output of the thermal power unit g in the t period of day d in the scenario s, is the unit power generation cost of the thermal power unit g and is a function related to the .
[0009] Preferably, the method for obtaining the new energy power increase indicator is: comparing the power generation of wind power and photovoltaic power with and without pumped storage, and quantifying the new energy power increase indicator of the pumped storage: ; ; wherein, is the actual output of wind farm w in scenario s at day d and time period t, is the actual output of photovoltaic power station p in scenario s at day d and time period t, is the actual output of photovoltaic power station p in scenario s at day d and time period t, is the total number of wind farms in the system, is the total number of photovoltaic power stations in the system, and DY is the total number of days in the evaluation year.
[0010] Preferably, the method for obtaining the carbon emission reduction amount is: quantifying the carbon emission reduction amount of pumped storage by comparing the carbon dioxide generated by fuel consumption of the system with and without pumped storage : ; ; wherein, is the carbon dioxide emission of the system in scenario s at day d and time period t, is the carbon dioxide emission of a single start-up of thermal power unit g in scenario s, is the carbon dioxide emission factor of thermal power unit g and is a function related to the , indicates the start-stop state of thermal power unit g at day d and time period t in scenario s, is 1, indicating operation, and is 0, indicating shutdown.
[0011] Preferably, the method for obtaining the frequency modulation capacity is: quantifying the frequency modulation capacity of pumped storage according to the operation of the pumped storage power station to be evaluated in the new power system : ; wherein, is the number of units of the pumped storage power station to be evaluated, and are the upper limit and lower limit of the active power output / load of unit i at day d and time period t, respectively.
[0012] Preferably, the method for obtaining the available reactive power amount is: quantifying the available reactive power amount of pumped storage according to the operation of the pumped storage power station to be evaluated in the new power system, in which the pumped storage generator only transmits inductive reactive power to the power grid in the power generation and phase modulation condition : ; wherein, the installed capacity of the pumped storage power station to be evaluated, the time period in which the pumped storage power station can be converted to a power generation and phase modulation working condition on day d.
[0013] Preferably, the method for obtaining the available rotational inertia is: quantifying the available rotational inertia according to the average kinetic energy of the pumped storage unit during operation wherein, is the inertia constant of the pumped storage unit i, is the rated capacity of the pumped storage unit i, is the start-stop state of the pumped storage unit i in the t time period on day d, 1 represents operation, 0 represents shutdown, and DY is the total number of days in the evaluation year.
[0014] Preferably, the method for obtaining the expected storage value is: quantifying the expected storage value according to the operation of the pumped storage power station to be evaluated in the new power system wherein, is the storage value of the pumped storage power station in the t time period on day d.
[0015] Preferably, the method for obtaining the comprehensive evaluation result based on the comprehensive score calculation model is: data preprocessing: taking the installed capacity as the measurement basis of each index, and each processed index represents the operation effect brought by 1 MW of pumped storage installed capacity; evaluation scale conversion, transforming the value of each index into a unified evaluation scale system; determining the weight of each index to obtain a comprehensive evaluation result wherein, is the weight of the i-th index, is the value of the i-th index transformed into the unified evaluation scale system.
[0016] The technical scheme of the present application has at least the following advantages and beneficial effects: The present application introduces economic, low-carbon, flexibility and reliability evaluation indexes in four dimensions, which can comprehensively reflect the multi-aspect role of pumped storage power station in the new power system, and improve the comprehensiveness of the evaluation. The application can accurately evaluate the promotion effect of pumped storage on new energy consumption by quantifying indicators such as new energy power and carbon emission reduction, so as to realize the attention to green and clean energy in the planning and operation of the power system; The application sets indicators such as frequency modulation capacity and reactive power, which helps to quantify the contribution of pumped storage to grid frequency modulation and pressure regulation, and the evaluation in this dimension can optimize the adjustment resource allocation and improve the ability of the system to respond to load fluctuations and grid disturbances; The application can quantify the contribution of pumped storage to system inertia support and backup capacity by introducing the available rotational inertia and expected energy storage value as indicators, which helps the grid operation mechanism to optimize the system stability strategy and enhance the fault response capability; The application fuses multi-dimensional data and then evaluates, which improves the unity of data and further enhances the reliability and accuracy of evaluation. BRIEF DESCRIPTION OF DRAWINGS
[0017] Fig. 1 The flowchart of the pumped storage operation evaluation method considering the multi-dimensional benefits of the new power system provided in Embodiment 1 of the application is shown in the figure. Fig. 2 The principle diagram of the pumped storage operation evaluation method considering the multi-dimensional benefits of the new power system provided in Embodiment 1 of the application is shown in the figure. DETAILED DESCRIPTION
[0018] In order to make the purpose, technical scheme and advantages of the embodiments of the application clearer, the technical scheme of the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are part of the embodiments of the application, not all the embodiments. The components of the embodiments of the application described and shown in the drawings can be arranged and designed in various configurations.
[0019] Embodiment 1 The embodiment provides a pumped storage operation evaluation method considering the multi-dimensional benefits of the new power system, which is described in Figs. 1-2 , including the following steps: Step S1A: Obtain the economic dimension indicators of pumped storage operation effect, and the economic dimension indicators include the replacement thermal power capacity indicator and the power saving indicator.
[0020] Firstly, the acquisition method of the replacement thermal power capacity indicator is as follows: Compare the system thermal power unit operation capacity with and without pumped storage, and quantify the replacement thermal power capacity indicator of pumped storage : ; ; wherein, is the thermal power operation capacity of the power system in the day d in the operation scenario s, DY is the total number of days in the evaluation year, s represents the scenario type, s is 1 when the system has pumped storage operation scenario, s is 0 when the system has no pumped storage operation scenario, represents the start-stop state of the thermal power unit g in the time period t of the day d in the scenario s, is 1 to represent operation, is 0 to represent shutdown, is the installed capacity of the thermal power unit g in the scenario s, is the total amount of thermal power units.
[0021] On the other hand, the acquisition method of the power saving index is: By comparing the operation cost of the system thermal power generation with and without pumped storage, the power saving index of pumped storage is quantified , the operation cost includes start-up cost and variable cost: ; ; wherein, is the total coal consumption of the system in the time period t of the day d in the scenario s, is the single start-up cost of the thermal power unit g, is the active power output of the thermal power unit g in the time period t of the day d in the scenario s, is the unit power generation cost of the thermal power unit g and is a function related to the .
[0022] In this step, by comparing the maximum thermal power operation capacity required by the system with and without pumped storage, the replacement ability of pumped storage for thermal power capacity can be accurately evaluated, which provides scientific evaluation for the system to reasonably reduce the thermal power installed capacity and improve renewable energy. The power saving index comprehensively considers the start-up cost and variable cost of the thermal power unit, and by comparing the scenarios with and without pumped storage, it can truly reflect the power saving effect of pumped storage on the system operation cost, which is helpful to improve the economic benefit of power system operation through the evaluation.
[0023] Step S1B: Obtain the low-carbon dimension index of pumped storage operation effect, the low-carbon dimension index includes increasing new energy power and reducing carbon emissions.
[0024] In this embodiment, the acquisition method of the increasing new energy power is: By comparing the wind power and photovoltaic power generation with and without pumped storage, the increasing new energy power of pumped storage is quantified: ; ; wherein, is the wind-solar renewable energy power generation in the d-day t period of the scenario s, s represents the scenario type, s is 1 when the system has a pumped storage operation scenario, s is 0 when the system has no pumped storage operation scenario, is the actual output of the wind farm w in the d-day t period of the scenario s, is the actual output of the photovoltaic power station p in the d-day t period of the scenario s, is the total number of wind farms in the system, is the total number of photovoltaic power stations in the system.
[0025] In addition, the method for obtaining the carbon emission reduction amount is: By comparing the carbon dioxide generated by the system fuel consumption with and without pumped storage, the carbon emission reduction amount of pumped storage is quantified : ; ; wherein, is the system carbon dioxide emission in the d-day t period of the scenario s, is the carbon dioxide emission of the thermal power unit g in a single start, is the carbon dioxide emission factor of the thermal power unit g and is a function related to the , represents the start-stop state of the thermal power unit g in the d-day t period of the scenario s, is 1 to indicate operation, is 0 to indicate shutdown.
[0026] Since the introduction of pumped storage system can store the wasted power due to volatility and uncontrollability in the system, thereby effectively improving the actual output utilization level of wind power and photovoltaic power, the quantified improved new energy power index can accurately and effectively reflect the ability of pumped storage to promote new energy consumption. By comparing the carbon emissions of the system as a whole with and without pumped storage, and refining the calculation of two types of contributions of start-up emissions and output emissions, the role of pumped storage in reducing the operation of coal-fired thermal power and reducing the carbon footprint of the system can be truly evaluated, which is a reliable support evaluation parameter for achieving the dual-carbon target.
[0027] Step S1C: obtaining a flexibility dimension index of pumped storage operation effect, the flexibility dimension index including a frequency modulation capacity and a reactive power.
[0028] As a preferred solution, the method for obtaining the frequency modulation capacity is: According to the operation of the pumped storage power station to be evaluated in the new power system, the available frequency modulation capacity is quantified : ; wherein, is the number of units of the pumped storage power station to be evaluated, and are the upper limit and the lower limit of the active power output / load of unit i in the t period of day d.
[0029] In addition, the method for obtaining the available reactive power is: In the generating and phase-modulating condition, the pumped storage generator only transmits inductive reactive power to the power grid, and according to the operation of the pumped storage power station to be evaluated in the new power system, the available reactive power of the pumped storage is quantified : ; wherein, is the installed capacity of the pumped storage power station to be evaluated, is the period in which the pumped storage power station can be converted to the generating and phase-modulating condition on day d.
[0030] Based on the above parameters, the frequency modulation capacity index is quantified by calculating the difference between the upper and lower limits of the pumped storage unit output, which can reflect the total capacity of the power station that can be used for dynamic adjustment of system frequency in each period. By quantifying the available reactive power of the pumped storage, the ability of the pumped storage power station to provide reactive power in the generating and phase-modulating condition is quantified, and the ability of the pumped storage to stabilize the voltage is measured.
[0031] Step S1D: Obtain the reliability dimension index of the pumped storage operation effect, and the reliability dimension index includes the available moment of inertia and the expected energy storage value.
[0032] In this embodiment, the method for obtaining the available moment of inertia is: According to the average kinetic energy of the pumped storage unit during operation, the available moment of inertia is quantified : ; wherein, is the inertia constant of pumped storage unit i, is the rated capacity of pumped storage unit i, is the start-stop state of pumped storage unit i in the t period of day d, is 1 for running and 0 for shutdown, and DY is the total number of days in the evaluation year.
[0033] On this basis, the method for obtaining the expected energy storage value is: According to the operation of the pumped storage power station to be evaluated in the new power system, the expected energy storage value is quantified : ; Among them, The energy storage value of the pumped storage power station at the t period of the d day.
[0034] In the reliability dimension index, the available moment of inertia index can accurately evaluate the inertia response level that the pumped storage power station can provide. The expected energy storage value can measure the energy storage capacity of the pumped storage power station in the whole year.
[0035] Step S2: The economy dimension index, the low-carbon dimension index, the flexibility dimension index and the reliability dimension index are all the higher the better, and the comprehensive evaluation result is obtained based on the comprehensive score calculation model according to the economy dimension index, the low-carbon dimension index, the flexibility dimension index and the reliability dimension index.
[0036] Specifically, the method for obtaining the comprehensive evaluation result based on the comprehensive score calculation model is: Data preprocessing: taking the installed capacity as the measurement basis of each index, and each processed index represents the operation effect brought by 1MW pumped storage installed capacity; Evaluation scale conversion, the value of each index is transformed into a unified evaluation scale system; It is particularly pointed out that the value of each index is uniformly transformed into [0, 100], and at the same time, the comprehensive evaluation result of the pumped storage power station that has been put into operation and the quasi-pumped storage power station is in the interval [60, 90], the following method can be preferably adopted: ; ; ; Among them, and are the maximum and minimum values of the selected index i in the pumped storage power station that has been put into operation and the quasi-pumped storage power station, and the calculated and are the values corresponding to the scores 100 and 0 of the index i respectively, is the transformed value corresponding to the index value .
[0037] Determine the weight of each index to obtain the comprehensive evaluation result : ; Among them, is the weight of the i-th index, The value of the i-th indicator is transformed into a unified evaluation scale system; The comprehensive evaluation results The higher the value, the better the evaluation of pumped storage operation.
[0038] Based on the principle of system value assessment, this embodiment combines the three core connotations of low carbon, safety and high efficiency of new power systems, and divides the benefits into four dimensions: economy, low carbon, flexibility and reliability, to analyze the operational effect reflected by the superposition of multiple effects of pumped storage.
[0039] Economic efficiency primarily reflects the "high efficiency" of the new power system, which can be summarized as reducing power supply costs while ensuring safety, stability, and power quality. This considers both fixed investment costs and daily operating costs.
[0040] Low carbon emissions primarily reflect the key characteristics of a "clean and low carbon" power system, including developing clean energy power and reducing coal consumption and carbon emissions from thermal power plants. The burning of fossil fuels for power generation is the root cause affecting the low carbon emissions of the power system.
[0041] Flexibility primarily reflects the key characteristic of the new power system: it can maintain real-time supply and demand balance and ensure sufficient power supply in the face of random disturbances in the power supply and load. Power dispatching agencies mainly stabilize frequency and voltage and improve power quality by increasing or decreasing the system's active or reactive power.
[0042] Reliability primarily reflects the "safety" connotation of a new power system, enabling it to withstand planned and unplanned component outages, as well as sudden disturbances, and to continuously provide power and electricity to users according to acceptable standards and required quantities. Inertia support can enhance the system's ability to cope with disturbances, while long-term power generation can ensure pumped storage power supply after an accident.
[0043] In summary, the technical solution of this embodiment constructs a comprehensive, standardized, and practically valuable evaluation index system for the operational performance of pumped storage power stations. This system covers four key benefit dimensions: economy, low carbon emissions, flexibility, and reliability, providing a solid theoretical foundation and evaluation framework for the scientific planning, rational selection, and sustainable development of pumped storage power stations. By establishing single-scoring models for each indicator and combining them with the analytic hierarchy process (AHP), a comprehensive evaluation model was constructed, enabling a quantitative assessment of the operational performance of pumped storage power stations. The evaluation results verify the impact of technical parameters such as installed capacity, regulation time, and conversion efficiency on the operational performance of pumped storage power stations, particularly highlighting the advantages of large-capacity, long-regulation-time, and high-efficiency pumped storage power stations across various benefit dimensions, which aligns with current policy directions.
[0044] The above merely describes the preferred embodiments of the present application, and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. An evaluation method for pumped storage operation considering multi-dimensional benefits of new power systems, characterized in that, The method comprises the following steps: An economic dimension index of the pumped storage operation effect is obtained, and the economic dimension index comprises a replacement thermal power capacity index and a power saving index; A low-carbon dimension index of the pumped storage operation effect is obtained, and the low-carbon dimension index comprises an increase in new energy power and a reduction in carbon emission; A flexibility dimension index of the pumped storage operation effect is obtained, and the flexibility dimension index comprises a frequency modulation capacity and a reactive power capacity; A reliability dimension index of the pumped storage operation effect is obtained, and the reliability dimension index comprises a moment of inertia and an expected energy storage value; A comprehensive evaluation result is obtained based on a comprehensive score calculation model according to the economic dimension index, the low-carbon dimension index, the flexibility dimension index and the reliability dimension index.
2. The method for evaluating the operation of pumped storage according to the multi-dimensional benefits of new power systems according to claim 1, characterized in that, The replacement thermal power capacity index is obtained by: Compare the operation capacity of the thermal power unit with and without pumped storage, and quantify the alternative thermal power capacity index of pumped storage : ； ； wherein, is the thermal power operation capacity of the power system in the running scenario s on day d, DY is the total number of days in the evaluation year, s represents the scenario type, s is 1 when the system has pumped storage, and s is 0 when the system has no pumped storage, represents the start-stop state of the thermal power unit g in scenario s on day d in period t, is 1 when running, is 0 when stopped, is the installed capacity of the thermal power unit g in scenario s, is the total amount of thermal power units.
3. The method for evaluating the operation of pumped storage according to claim 2, wherein The power saving index is obtained by: By comparing the operation cost of the thermal power generating unit with and without the pumped storage, the saved power generation index of the pumped storage is quantified , the operation cost includes the start-up cost and the variable cost ； ； wherein, is the total coal consumption of the system in scenario s on day d at time period t, is the single start-up cost of thermal power unit g, is the active power output of thermal power unit g in scenario s on day d at time period t, is the unit generation cost of thermal power unit g and is a function related to the . 4.The method of claim 1, wherein, The promotion of new energy power The acquisition method is: By comparing the power generation of wind power and photovoltaic with and without pumped storage, the improvement of new energy power generation by pumped storage is quantified : ； ； wherein, is the wind and light renewable energy power generation in the d-day t period in the scenario s, s represents the scenario type, s is 1 when the system has the operation scenario of the pumped storage, s is 0 when the system has the operation scenario without the pumped storage, is the actual output of the wind farm w in the d-day t period in the scenario s, is the actual output of the photovoltaic power station p in the d-day t period in the scenario s, is the total number of wind farms in the system, is the total number of photovoltaic power stations in the system, and DY is the total number of days in the evaluation year.
5. The method for evaluating the operation of pumped storage according to claim 4, wherein The reduction in carbon emission is obtained by: By comparing the carbon dioxide produced by the system fuel consumption with and without pumped storage, the carbon emission reduction of pumped storage is quantified : ； ； wherein, is the system carbon dioxide emission in the d-th day t-th period in the scenario s, is the single start carbon dioxide emission of the thermal power unit g in the scenario s, is the carbon dioxide emission factor of the thermal power unit g and is a function related to the , represents the start-stop state of the thermal power unit g in the d-th day t-th period in the scenario s, is 1, representing running, is 0, representing shutdown. 6.The method of claim 1, wherein the method is characterized by, The frequency modulation capacity is obtained by: According to the operation condition of the pumped storage power station to be evaluated in the new power system, the frequency regulation capacity available is quantified : ； wherein, is the number of units of the pumped storage power plant to be evaluated, and are the upper and lower limits of the active power output / load of unit i at the t period of day d, respectively.
7. The method for evaluating the operation of pumped storage considering the multi-dimensional benefits of new power systems according to claim 6, characterized in that, The reactive power capacity is obtained by: In the power generation and phase modulation condition, the pumped storage generator only supplies inductive reactive power to the power grid. According to the operation condition of the pumped storage power station to be evaluated in the new power system, the available reactive power of the pumped storage power station is quantified : ； wherein, the installed capacity of the pumped storage power station to be evaluated, is the time period in which the pumped storage power station can be converted to power generation and phase modulation mode on day d. 8.The method of claim 1, wherein the method is characterized by, The moment of inertia is obtained by: quantifying the available moment of inertia according to the average kinetic energy of the pumped storage unit during operation : ； wherein, is the inertia constant of pumped storage unit i, is the rated capacity of pumped storage unit i, is the start-stop state of pumped storage unit i in day d and time period t, is 1 for operation and 0 for shutdown, and DY is the total number of days in the evaluation year. 9.The method for evaluating the operation of the pumped storage power station considering the multi-dimensional benefits of the new power system according to claim 8, characterized in that, The expected energy storage value is obtained by: According to the operation situation of the pumped storage power station to be evaluated in the new power system, the expected energy storage value is quantified : ； wherein, the pumped storage power station's storage value at day d and time period t. 10.The method for evaluating the operation of pumped storage considering the multi-dimensional benefits of new power systems according to claim 8, characterized in that, The comprehensive evaluation result is obtained based on the comprehensive score calculation model by: Data preprocessing is performed: the installed capacity is taken as a measurement benchmark of each index, and each index after processing represents the operation effect brought by 1 MW of pumped storage installed capacity; Evaluation scale conversion is performed, and the value of each index is converted into a unified evaluation scale system; determining the weight of each index to obtain a comprehensive evaluation result : ； wherein, is the weight of the i-th indicator, is the value of the i-th indicator transformed into a unified evaluation scale system.