State perception method for urban integrated energy system

Abstract

A state perception method for urban integrated energy systems establishes indicators for various energy conditions in the city, including energy supply reliability, energy safety and energy utilization efficiency of each site, including electrical equipment performance indicators, system operation status indicators, economic and social benefit quantitative indicators and a comprehensive evaluation index system for reliability.

Description

Technical Field

[0001] The present invention relates to a technology in the field of distribution network control, and specifically to a state perception method for an urban integrated energy system. Background Art

[0002] The urban integrated energy system is the key development direction of the future urban energy network. The urban integrated energy system with electricity as the main body and integrated with various energy forms such as natural gas and thermal energy will become an important development trend of urban energy supply in the future. The urban economy is constrained by factors such as unreasonable energy structure, low efficiency, and poor safety. Therefore, the source data has the potential value as an economic "barometer". From energy planning, construction, and operation, it is particularly important to promote the integration of cities and energy and the collaborative sharing of resources. Research on data fusion prediction technology, realize the accurate prediction of renewable energy and heat, electricity, cold, gas and other loads at different time scales, and intelligent perception of the status of urban integrated energy systems. Summary of the invention

[0003] In view of the above-mentioned deficiencies in the prior art, the present invention proposes a state perception method for an urban integrated energy system, and establishes indicators for various energy conditions in the city, including energy supply reliability, energy safety and energy utilization efficiency of each site, which covers electrical equipment performance indicators, system operation status indicators, economic and social benefit quantitative indicators and a comprehensive evaluation index system for reliability.

[0004] The present invention is achieved through the following technical solutions:

[0005] The present invention relates to a state perception method for an urban integrated energy system. A state perception evaluation index model is established from the perspective of energy supply reliability of the urban integrated energy system. A state perception evaluation index model is established for energy safety and energy utilization efficiency. A method combining a hierarchical analysis method with a fuzzy comprehensive evaluation method is adopted to determine the weight ratio and state membership function of indicators at all levels, and establish the result of the comprehensive evaluation, i.e., a four-layer indicator.

[0006] The four layers of indicators refer to: the overall evaluation index of the urban comprehensive system, that is, the highest-level indicator, which includes the second-level indicators, namely energy supply reliability, energy use safety and energy utilization efficiency; the second-level indicators include the third-level indicators, among which the power supply reliability indicators include the average power outage time of the system, the average power supply reliability rate, the average power outage frequency of the system, the average short-term power outage frequency of the system, the average system equivalent power outage time and the average system equivalent power outage frequency; the heating reliability indicators include the heating guarantee rate, the heating non-guaranteed time, the probability of accident-free work and the accident rate; energy use safety covers electrical energy and thermal energy, including equipment failure probability, leakage detection threshold, power supply voltage deviation, gas transportation pipeline wall thickness, gas leakage injury index and gas pipeline service life; energy utilization efficiency.

[0007] The fourth level of indicators in the four levels of indicators include:

[0008] 1) Average power outage time of the system, specifically: the average number of power outage hours for power supply system users during the statistical period, that is, When external influences are ignored, If the power shortage of the system is ignored, then When short-term power outages are not considered,

[0009] 2) Average power supply reliability rate: the ratio of the number of hours of effective power supply to users during the statistical period to the number of hours during the statistical period, that is, When external influences are ignored, If the power shortage of the system is ignored, then When short-term power outages are not considered,

[0010] 3) System average power outage frequency: the average number of power outages for power supply system users during the statistical period, i.e. When external influences are ignored, If the power shortage of the system is ignored, then When short-term power outages are not considered,

[0011] 4) System average short-term power outage frequency: the average number of short-term power outages for power supply system users during the statistical period, i.e.

[0012] 5) Average system equivalent outage time: During the statistical period, the impact of system outage on users is converted into the equivalent number of hours of power outage for the entire system (all users), that is,

[0013] 6) Average system equivalent outage frequency: During the statistical period, the impact of system outages on users is converted into the equivalent number of outages in the entire system (all users), that is,

[0014] 7) Heat supply guarantee rate It is the average probability of a certain heat user being in a non-failure state during the heating period. It can be understood as the ratio of the average time during the heating period to ensure that the heat user does not fail to meet the requirements and the total time of the heating period. Where: N zh is the total heating hours, h; When component i fails, the duration of the outdoor temperature of the heat user j corresponding to type r heat user is not guaranteed, h. Where: when i = 0, all components are in good condition. At this time, for all heat users, the duration of the outdoor temperature of the heat user room temperature is not guaranteed is the same, and this part can be proposed separately; in: The duration of time that the indoor temperature of the heating system during the entire heating period is less than the outdoor temperature required by the design when all components are intact, h. In my country, it is generally 5 days, i.e. 120h.

[0015] 8) Heating unguaranteed time: It is a change of heating guarantee rate, which is the average time that the indoor temperature during the heating period is lower than a certain indoor temperature required by the heat user, that is, the average time that the heat user is unreliable

[0016] 9) Accident-free operation probability: the probability that no accident occurs to a certain heat user during the heating period, that is, the probability that the room temperature of the heat user is not lower than the minimum allowable indoor temperature during the heating period.

[0017] 10) Accident rate: represents the average number of accidents that occur to a certain heat user each year Taking the inverse of this gives the average number of years in which an accident occurs for heat users;

[0018] 11) Equipment failure probability:

[0019] 12) Leakage detection threshold: Use a wireless leakage detector and adjust the detection alarm threshold according to the specific detection environment before installation: 1 corresponds to 30mA, 2 corresponds to 60mA, 3 corresponds to 90mA, and 4 corresponds to 120mA;

[0020] 13) Power supply voltage deviation: If the actual voltage is too high, it will cause overvoltage of the equipment, threaten insulation and reduce service life; if the actual voltage is too low, it will affect the normal work of the user, causing the user's equipment and electrical appliances to fail to operate normally or stop operating. At this time, consider the power supply voltage qualification rate: power supply voltage qualification rate = [0.5A + 0.5 (B + C + D) / 3] × 100%, where: A represents 110kv bus, B represents 35KV and above, C represents 10kV and above, D represents 380 / 220 user side voltage, and the voltage qualification rate of each point is:

[0021] 13) Gas transportation pipeline wall thickness: The thickness of the gas transportation pipeline can be considered the effective wall thickness Where: t is the pipe wall thickness, D is the average diameter of the pipe, d is the depth of the defect, and L is the length of the defect;

[0022] 14) Gas Leakage Damage Index: The gas leakage damage index is the incident heat radiation intensity received by people. Where: Q is the heat radiation flux W when the fireball burns, T c is the conduction coefficient, the conservative value is 1, x is the horizontal distance m between the target and the center of the fireball;

[0023] 15) Pipeline service life: Pipeline service life;

[0024] 16) Energy equipment utilization efficiency Where: η d is the energy equipment utilization rate, E d is the total energy output of the energy equipment per year, kJ; P is the rated power of the equipment, kW;

[0025] 17) Annual average comprehensive energy utilization rate Where: W is the annual power output of the combined heat and power supply system, kW·h; ta is the annual utilization hours; Q1 is the annual effective waste heat heating, MJ; h represents heating, c represents cooling; Q2 is the annual effective waste heat cooling, MJ; B is the annual total fuel consumption of the combined heat and power supply system, m3; QL is the low calorific value of the fuel, MJ / m3; Pt is the heat available when the flue gas is reduced to different temperatures; t is the utilization hours in different seasons; P 100 The heat available when the temperature drops to 100°C; C Op is the cooling coefficient, q v is the gas consumption, m3 / h;

[0026] 18) Distributed cooling, heating and electricity energy saving rate: Where: CCHP is the energy saving rate of the distributed cooling, heating and power energy system, E r is the energy consumption of the distributed cooling, heating and power energy system during the reporting period, in kilograms of standard coal (kgce), E a is the calibrated energy consumption of the distributed cooling, heating and power energy system, in kilograms of standard coal (kgce);

[0027] 19) Comprehensive efficiency of power station: The comprehensive efficiency of energy storage power station should be the ratio of online power to offline power during the production and operation of energy storage power station during the evaluation period, calculated as follows: Where: η EESS is the comprehensive efficiency of the energy storage power station, %; E on is the amount of electricity that the energy storage power station consumes during the evaluation period, in kilowatt-hours (kW·h); E off The amount of electricity that the energy storage power station generates during the evaluation period, in kilowatt-hours (kW·h);

[0028] 20) Power Transformer and Distribution Loss Rate of Power Station: The power transformer and distribution loss rate should be the percentage of power loss of the power transmission and transformation equipment supporting the energy storage system in the energy storage power station during operation to the off-grid power during the evaluation period, which can be calculated as follows: R i =1-η EESS -R ES -R S , where: R i is the power distribution loss rate, %; R S is the power consumption rate of the station, %; η EESS is the comprehensive efficiency of the energy storage power station, %; R ES is the power station energy storage loss rate, %; E on is the amount of electricity that the energy storage power station consumes during the evaluation period, in kilowatt-hours (kW·h); E off is the amount of electricity that the energy storage power station generates during the evaluation period, in kilowatt-hours (kW·h); ∑E S is the total power consumption of the energy storage power station during the evaluation period, in kilowatt-hours (kW·h); ∑E C is the total charge of each energy storage unit during the evaluation period, in kilowatt-hours (kW·h); ∑E D It is the sum of the discharge of each energy storage unit during the evaluation period, in kilowatt-hours (kW·h);

[0029] 21) Power station energy storage loss rate: The energy storage loss rate should be the ratio of the total energy loss of each energy storage unit during the evaluation period of the energy storage power station to the total amount of electricity off the grid, calculated as follows: Where: R ES is the station energy storage loss rate, %; ∑E C is the total charge of each energy storage unit during the evaluation period, in kilowatt-hours (kW·h); ∑E D E is the total discharge amount of each energy storage unit during the evaluation period, in kilowatt-hours (kW·h); off The amount of electricity that the energy storage power station generates during the evaluation period, in kilowatt-hours (kW·h);

[0030] 22) Photovoltaic power station energy efficiency ratio: Among them: PR T E is the energy efficiency ratio of the power station in the T time period. T P is the amount of electricity that the power station inputs into the grid during the T period. e It is the nominal capacity of the power station components. T is the peak sunshine hours on the square array surface during the T period. , where: PR T The value is the value within a period of time. Since it is calculated based on a power generation year, it can best represent the situation of a power plant, and usually the time range is one year. TIt must be the actual amount of electricity that the photovoltaic power station inputs into the grid, which is the metering value at the photovoltaic power station gateway, and cannot be the amount of electricity that the photovoltaic power station itself generates. e It is the sum of the nominal capacities of all components actually installed in the PV power station, not the nominal capacity. T It is the peak sunshine hours on the array surface of the photovoltaic power station. The peak sunshine hours refer to the ratio of the total radiation received on an area of ​​1m2 (kW·h / m2) to the corresponding radiation intensity of 1000W / m2 under the standard test conditions STC, and the unit is h;

[0031] 23) Wind power plant field loss rate

[0032] 24) Comprehensive line loss rate of distribution network

[0033] 25) Comprehensive loss rate of distribution transformer

[0034] 26) Power supply load factor: the ratio of power consumption of the power supply and distribution system to the power consumption of the equipment Where: P power is the power consumption of the power supply and distribution system, and P is the power consumed by the equipment;

[0035] 27) Pipeline network heat loss rate Q = 2 × π × k × L (T1-T2) / [ln (r2 / r1)], where: k = pipe material, heat transfer coefficient, T1 = internal temperature of the pipe, which can be assumed to be the same as the temperature of the fluid, T2 = outside temperature of the pipe, which can be assumed to be the same as the temperature of the air outside the pipe, L = length of the pipe where the fluid will be transported, r1 = pipe inner diameter, r2 = pipe outer radius, ln = natural logarithm, π = 3.14159;

[0036] 28) System power consumption and heat transfer ratio Where: Q is the shaft power of the pump at the design operating point, kW; Q is the building heating load, kW; η is the efficiency of the motor and transmission part, which is 0.85 when directly connected; and 0.83 when a coupling is used;

[0037] 29) Typical daily comprehensive energy efficiency of solar water heaters Where: c is the specific heat of water, 4.18 kJ / kg.℃; ρ is the density of water, 1000 kg / m3;

[0038] 30) Pipeline operation pressure loss: Pressure loss, also known as pressure drop or pressure loss, is a technical and economic indicator that indicates the energy consumption of a device. It is expressed as the total pressure difference of the fluid at the inlet and outlet of the device. It essentially reflects the mechanical energy consumed by the fluid passing through the dust removal device (or other device) and is proportional to the power consumed by the fan:

[0039] a) Assume that the gas density is ρ, the velocity is v, the pipe diameter is D, the length is L, the gas flow friction coefficient is f, and the pressure loss = (f×L / D)×0.5×ρ×v 2 ;

[0040] b) For long pipelines, local pressure loss can be ignored, and the total pressure loss in the pipeline is: P w =P f =0.5(λL / d)ρV2 or P w =ρgsLQ 2 , where: ρ is the fluid density; g is the acceleration due to gravity; s is the pipeline resistance; L is the pipeline length; Q is the pipeline flow rate. The relationship between pipeline resistance and the resistance coefficient along the way: s = 8λ / (gπ 2 d 5 ).

[0041] Technical Effects

[0042] Compared with the prior art, the target object of the present invention is the urban integrated energy system, rather than the traditional distribution network system, and a state perception evaluation index system based on energy supply reliability, energy safety and energy utilization efficiency is established. A method combining tomography analysis and fuzzy comprehensive evaluation is used to perform situation perception of the urban integrated energy system, and the results are divided into four categories: normal, abnormal, fault and post-fault. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A schematic diagram of a comprehensive evaluation index system for an urban comprehensive energy system according to the present invention;

[0044] Figure 2 It is a schematic diagram of the hierarchical structure model of the hierarchical analysis method of the present invention;

[0045] Figure 3 This is an evaluation flow chart of the state perception of the urban integrated energy system of the present invention. DETAILED DESCRIPTION

[0046] This embodiment involves a state perception method for an urban integrated energy system, which comprehensively considers the evaluation index models of energy storage power stations, data centers, electric vehicle charging and discharging stations, 5G base stations and other sites, and establishes a comprehensive evaluation for multi-site integration transformation. A method combining the layered analysis method and the fuzzy comprehensive evaluation method is used to determine the weight ratio and state membership of indicators at all levels, and obtain the indicator weight system at each level, which specifically includes:

[0047] Secondary indicators

[0048]

[0049] In order to make the results of the comprehensive evaluation index system of power supply reliability more scientific, quantitative evaluation indicators are selected as the final reference standards.

[0050]

[0051] In order to make the results of the comprehensive evaluation index system of heating reliability more scientific, quantitative evaluation indicators are selected as the final reference standards.

[0052]

[0053] In order to make the results of the comprehensive evaluation index system of energy safety more scientific, quantitative evaluation indicators are selected as the final reference standards.

[0054]

[0055]

[0056] In order to make the results of comprehensive evaluation index system of energy utilization efficiency more scientific, quantitative evaluation index is selected as the final reference standard.

[0057]

[0058]

[0059] The relevant weight ratio is determined through a specific hierarchical analysis method, and is brought into the fuzzy membership function to score each indicator. Its status can be divided into normal or not according to the score.

[0060] Compared with the existing technology, this method targets the urban integrated energy system and establishes a state perception evaluation index system based on energy supply reliability, energy safety and energy utilization efficiency. The method combines the tomography analysis method with the fuzzy comprehensive evaluation method to conduct situation perception of the urban integrated energy system, and divides the results into four categories: normal, abnormal, fault and post-fault.

[0061] The above-mentioned specific implementation can be partially adjusted in different ways by those skilled in the art without departing from the principle and purpose of the present invention. The protection scope of the present invention shall be based on the claims and shall not be limited by the above-mentioned specific implementation. Each implementation scheme within its scope shall be subject to the constraints of the present invention.

Claims

1. A state perception method for an urban integrated energy system, characterized in that: By establishing a state perception evaluation index model, the weight ratio of each level of indicators and the state membership function are determined by combining the tomography analysis method with the fuzzy comprehensive evaluation method, and the results of the comprehensive evaluation are established, namely, four categories: normal, abnormal, fault and post-fault; The highest level indicator is the overall evaluation indicator of the urban comprehensive system, which includes the second level indicators, namely energy supply reliability, energy use safety and energy utilization efficiency; The second-tier indicators include the third-tier indicators, among which energy supply reliability includes power supply reliability indicators and heat supply reliability indicators; Energy safety includes electrical energy safety and thermal energy safety; Energy utilization efficiency includes: system comprehensive energy efficiency, electric energy utilization efficiency index and thermal energy utilization efficiency index; The third level indicators include the fourth level indicators, which include: Power supply reliability indicators include system average power outage time, average power supply reliability rate, system average power outage frequency, system average short-term power outage frequency, average system equivalent power outage time and average system equivalent power outage frequency; The heat supply reliability indicators include heat supply guarantee rate, heat supply non-guarantee time, accident-free operation probability and accident rate; Equipment failure probability, leakage detection threshold, and supply voltage deviation for power safety; Thermal safety of gas transportation pipeline wall thickness, gas leakage injury index and gas pipeline service life; The energy equipment utilization efficiency, annual average comprehensive energy utilization rate and distributed cooling, heating and electricity energy saving rate of the system comprehensive energy efficiency; Electric energy utilization efficiency indicators: comprehensive efficiency of substations, power distribution loss rate of power stations and energy storage loss of substations for power substations, photovoltaic power generation efficiency ratio for photovoltaic power generation, wind power generation field loss rate for wind power generation, comprehensive line loss rate of distribution networks, comprehensive loss rate of distribution transformers and power supply load factor for power grid users; The heat loss rate of the pipe network, the system power consumption and heat transmission ratio, the daily comprehensive energy efficiency of the solar water heater and the pressure loss of the pipeline operation are the heat energy utilization efficiency indicators, including: 1) Average power outage time of the system, specifically: the average number of power outage hours for power supply system users during the statistical period, that is, When external influences are ignored, If the power shortage of the system is ignored, then When short-term power outages are not considered, 2) Average power supply reliability rate: the ratio of the number of hours of effective power supply to users during the statistical period to the number of hours during the statistical period, that is, When external influences are ignored, If the power shortage of the system is ignored, then When short-term power outages are not considered, 3) System average power outage frequency: the average number of power outages for power supply system users during the statistical period, i.e. When external influences are ignored, If the power shortage of the system is ignored, then When short-term power outages are not considered, 4) System average short-term power outage frequency: the average number of short-term power outages for power supply system users during the statistical period, i.e. 5) Average system equivalent power outage time: During the statistical period, the impact of system power outage on users is converted into equivalent hours of system power outage, that is, 6) Average system equivalent outage frequency: During the statistical period, the impact of system outages on users is converted into the equivalent number of system-wide outages, that is, 7) Heat supply guarantee rate It is the average value of the probability that a certain heat user is in a state without failure during the heating period, which is understood as the ratio of the average time that can ensure that the heat user does not fail during the heating period to the total time of the heating period. Where: N zh is the total heating hours, h; When component i fails, the duration h of the outdoor temperature of the heat user j corresponding to type r heat user whose room temperature is not guaranteed, where: when i=0, all components are in good condition. At this time, for all heat users, the duration of the outdoor temperature of the heat user room temperature is not guaranteed is the same, and this part can be proposed separately; in: The duration of time that the indoor temperature of the heating system during the entire heating period is less than the outdoor temperature required by the design when all components are intact, h. In my country, it is 5 days, i.e. 120h. 8) Heating unguaranteed time: It is a change of heating guarantee rate, which is the average time that the indoor temperature during the heating period is lower than a certain indoor temperature required by the heat user, that is, the average time that the heat user is unreliable 9) Accident-free operation probability: the probability that no accident occurs to a certain heat user during the heating period, that is, the probability that the room temperature of the heat user is not lower than the minimum allowable indoor temperature during the heating period. 10) Accident rate: represents the average number of accidents that occur to a certain heat user each year Taking the inverse of this gives the average number of years in which an accident occurs for heat users; 11) Equipment failure probability: 12) Leakage detection threshold: Use a wireless leakage detector and adjust the detection alarm threshold according to the specific detection environment before installation: 1 corresponds to 30mA, 2 corresponds to 60mA, 3 corresponds to 90mA, and 4 corresponds to 120mA; 13) Power supply voltage deviation: If the actual voltage is too high, it will cause overvoltage of the equipment, threaten insulation and reduce service life; if the actual voltage is too low, it will affect the normal work of the user, causing the user's equipment and electrical appliances to fail to operate normally or stop operating. At this time, consider the power supply voltage qualification rate: power supply voltage qualification rate = [0.5A + 0.5 (B + C + D) / 3] × 100%, where: A represents 110kv bus, B represents 35KV and above, C represents 10kV and above, D represents 380 / 220 user side voltage, and the voltage qualification rate of each point is: 14) Gas transportation pipeline wall thickness: The thickness of the gas transportation pipeline, taking into account the effective wall thickness Where: t is the pipe wall thickness, D is the average diameter of the pipe, d is the depth of the defect, and L is the length of the defect; 15) Gas Leakage Damage Index: The gas leakage damage index is the incident heat radiation intensity received by people. Where: Q is the heat radiation flux W when the fireball burns, T c is the conduction coefficient, the conservative value is 1, x is the horizontal distance m between the target and the center of the fireball; 16) Pipeline service life: Pipeline service life; 17) Energy equipment utilization efficiency Where: η d is the energy equipment utilization rate, E d is the total energy output of the energy equipment per year, kJ; P is the rated power of the equipment, kW; 18) Annual average comprehensive energy utilization rate Where: W is the annual power output of the combined heat and power supply system, kW·h; ta is the annual utilization hours; Q1 is the annual effective waste heat heating amount, MJ; h represents heating, c represents cooling; Q2 is the annual effective waste heat cooling amount, MJ; B is the annual total fuel consumption of the combined heat and power supply system, m3; QL is the low calorific value of the fuel, MJ / m3; Pt is the heat available when the flue gas is reduced to different temperatures; t is the utilization hours in different seasons; P 100 The heat available when the temperature drops to 100°C; Op is the cooling coefficient, q v is the gas consumption, m3 / h; 19) Distributed cooling, heating and electricity energy saving rate: Where: CCHP is the energy saving rate of the distributed cooling, heating and power energy system, E r is the energy consumption of the distributed cooling, heating and power energy system during the reporting period, in kilograms of standard coal (kgce), E a is the calibrated energy consumption of the distributed cooling, heating and power energy system, in kilograms of standard coal (kgce); 20) Comprehensive efficiency of power station: The comprehensive efficiency of energy storage power station should be the ratio of online power to offline power during the production and operation of energy storage power station during the evaluation period, calculated as follows: Where: η EESS is the comprehensive efficiency of the energy storage power station, %; E on is the amount of electricity that the energy storage power station consumes during the evaluation period, in kilowatt-hours (kW·h); E off The amount of electricity that the energy storage power station generates during the evaluation period, in kilowatt-hours (kW·h); 21) Power Transformer and Distribution Loss Rate of Power Station: The power transformer and distribution loss rate should be the percentage of power loss of the power transmission and transformation equipment supporting the energy storage system in the energy storage power station during operation to the off-grid power during the evaluation period, which can be calculated as follows: R i =1-η EESS -R ES -R S , where: R i For Change Distribution loss rate, %; R S is the power consumption rate of the station, %; η EESS is the comprehensive efficiency of the energy storage power station, %; R ES is the power station energy storage loss rate, %; E on The amount of electricity that the energy storage power station consumes during the evaluation period, in kilowatt-hours (kW·h ) ; E off is the amount of electricity that the energy storage power station generates during the evaluation period, in kilowatt-hours (kW·h); ∑E S is the total power consumption of the energy storage power station during the evaluation period, in kilowatt-hours (kW·h); ∑E C is the total charge of each energy storage unit during the evaluation period, in kilowatt-hours (kW·h); ∑E D It is the sum of the discharge of each energy storage unit during the evaluation period, in kilowatt-hours (kW·h); 22) Power station energy storage loss rate: The energy storage loss rate should be the ratio of the total energy loss of each energy storage unit during the evaluation period of the energy storage power station to the total amount of electricity off the grid, calculated as follows: Where: R ES is the station energy storage loss rate, %; ∑E C is the total charge of each energy storage unit during the evaluation period, in kilowatt-hours (kW·h); ∑E D E is the total discharge amount of each energy storage unit during the evaluation period, in kilowatt-hours (kW·h); off The amount of electricity that the energy storage power station generates during the evaluation period, in kilowatt-hours (kW·h); 23) Photovoltaic power station energy efficiency ratio: Among them: PR T is the energy efficiency ratio of the power station in the T period, E T P is the amount of electricity that the power station inputs into the grid during the T period, e is the nominal capacity of the power station components, h T is the peak sunshine hours on the square array surface during the T period, where: PR T The value is the value within a period of time. Since it is calculated based on a power generation year, it can best represent the situation of a power station. Taking one year as the time range, E T It is the actual amount of electricity input into the grid by the photovoltaic power station. It is the gateway metering value of the photovoltaic power station. It cannot be the amount of electricity generated by the photovoltaic power station itself. e It is the sum of the nominal capacities of all components actually installed in the PV power station, not the nominal capacity. T It is the peak sunshine hours on the array surface of the photovoltaic power station. The peak sunshine hours refer to the ratio of the total radiation received on an area of ​​1m2 (kW·h / m2) to the corresponding radiation intensity of 1000W / m2 under the standard test conditions STC, and the unit is h; 24) Wind power plant field loss rate 25) Comprehensive line loss rate of distribution network 26) Comprehensive loss rate of distribution transformer 27) Power supply load factor: the ratio of power consumption of the power supply and distribution system to the power consumption of the equipment Where: P power is the power consumption of the power supply and distribution system, and P is the power consumed by the equipment; 28) Pipeline heat loss rate Q = 2 × π × k × L (T1-T2) / [ln (r2 / r1)], where: k = pipe material, heat transfer coefficient, T1 = internal temperature of the pipe, assumed to be the same as the temperature of the fluid, T2 = outside temperature of the pipe, assumed to be the same as the temperature of the air outside the pipe, L = length of the pipe the fluid will be transported, r1 = pipe inner diameter, r2 = pipe outer radius, ln = natural logarithm, π = 3.14159; 29) System power consumption and heat transfer ratio Where: Q is the shaft power of the pump at the design operating point, kW; Q is the building heating load, kW; η is the efficiency of the motor and transmission part, which is 0.85 when directly connected; and 0.83 when a coupling is used; 30) Typical daily comprehensive energy efficiency of solar water heaters Where: c is the specific heat of water, 4.18 kJ / kg.℃; ρ is the density of water, 1000 kg / m3; 31) Pipeline operation pressure loss: Pressure loss, also known as pressure drop or pressure loss, is a technical and economic indicator that indicates the energy consumption of the device. It is expressed as the total pressure difference of the fluid at the inlet and outlet of the device. It actually reflects the mechanical energy consumed by the fluid passing through the dust removal device and is proportional to the power consumed by the fan: a) Assume that the gas density is ρ, the velocity is v, the pipe diameter is D, the length is L, the gas flow friction coefficient is f, and the pressure loss = (f×L / D)×0.5×ρ×v 2 ; b) For long pipelines, local pressure loss can be ignored, and the total pressure loss in the pipeline is: P w =P f =0.5(λL / d)ρV2 or P w =ρgsLQ 2 , where: ρ is the fluid density; g is the gravitational acceleration; s is the pipeline resistance; L is the pipeline length; Q is the pipeline flow rate. The relationship between pipeline resistance and the resistance coefficient along the way is: s = 8λ / (gπ 2 d 5 ).

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