CN115660142A - A source-load-storage coordination optimization scheduling method for park integrated energy system - Google Patents

Abstract

The present invention relates to a source-load-storage coordination and optimization scheduling method for a park comprehensive energy system, which constructs an electric-heat-gas park comprehensive energy system including power-to-gas, wind turbines, photovoltaic units, combined heat and power units, and energy storage equipment; considering Power-to-gas participates in the natural gas trading market and electricity trading market of the park's comprehensive energy system, and establishes a source-load-storage coordination optimization model of the park's comprehensive energy system; the optimal scheduling model includes constraints and objective functions, and the system operation optimal scheduling model is constrained by the constraints , taking the lowest total system cost as the objective function to solve the optimal solution of the optimization result; when optimizing the comprehensive energy system of the park, considering the power-to-gas unit can realize the complementary advantages of each unit in the system, improve energy utilization efficiency, and coordinate the optimization of the power supply in the network. The combined heat and power unit operates more flexibly, which saves the energy consumption cost of the comprehensive energy system.

Description

A source-load-storage coordination optimization scheduling method for park integrated energy system

technical field

The invention relates to a source-load-storage coordination and optimization scheduling method for a comprehensive energy system in a park, belonging to the technical field of electric power industry.

Background technique

At present, the proportion of new energy installed capacity continues to increase, and the problem of abandoning wind and solar is very serious. In order to avoid waste of resources, the power-to-gas (P2G) system can use the surplus electricity of new energy to decompose water H ₂ O into oxygen O ₂ and hydrogen H ₂ through the electrolysis water module. When H ₂ lacks large-scale direct storage or other consumption methods, the methanation module is further used to react it with CO ₂ to synthesize CH ₄ and inject it into natural gas pipelines to promote the consumption of new energy.

As the proportion of new energy installed capacity continues to increase, the pressure on system peak regulation is increasing. The construction of P2G plants and wind farms, photovoltaic power stations or comprehensive energy systems will be the focus of future research. Therefore, the coupling of energy flow of aggregated power-to-gas units Value, the research considers the coordinated control and scheduling optimization of the park's comprehensive energy system including power-to-gas, so as to maximize the consumption of new energy.

For example, Chinese patent CN111639824B is a thermoelectric optimization scheduling method for regional comprehensive energy systems including power-to-gas, including: analyzing the two-stage operation mechanism of power-to-gas, introducing hydrogen storage in the hydrogen production link of electrolyzed water, and promoting high hydrogen energy through hydrogen fuel cell cogeneration Grade use reduces energy cascade utilization loss caused by direct methanation; optimizes hydrogen fuel cell and cogeneration units to variable efficiency operation, flexibly tracks thermoelectric load situation by adjusting thermoelectric efficiency, and makes thermoelectric output more economical and reasonable; introduces organic Lang Ken cycle waste heat power generation converts the excess heat output of combined heat and power into electric energy, and improves the thermoelectric coupling performance of the system by promoting waste heat absorption; with the goal of minimizing the sum of system energy purchase cost, operation and maintenance cost, and energy loss cost, a Thermoelectric coupled RIES optimal scheduling model for power-to-gas. The method can improve the energy utilization efficiency and cogeneration performance of the regional comprehensive energy system, and has the advantages of scientific rationality, strong applicability, and good effect.

This method focuses on effectively reducing the energy loss cost of the regional integrated energy system by improving the comprehensive energy utilization rate; an energy coordination scheduling method that focuses on economic benefits is needed.

Contents of the invention

The purpose of the present invention is to provide a coordinated optimization scheduling method for source-load-storage of an integrated energy system in a park, so as to solve the problems raised in the above-mentioned background technology.

Technical scheme of the present invention is as follows:

A source-load-storage coordination and optimization scheduling method for a comprehensive energy system in a park, comprising the following steps:

A park comprehensive energy system including power-to-gas, wind turbines, photovoltaic units, combined heat and power units, and energy storage equipment has been constructed;

Consider the participation of power-to-gas in the natural gas trading market and power trading market of the park's comprehensive energy system, and establish an optimal scheduling model;

The optimal scheduling model includes constraints and objective functions. Under the constraints of the constraints, the optimal scheduling model for system operation takes the lowest total system cost as the objective function to solve the optimal solution of the optimization results;

The objective function is:

Min F＝F ^MT +F ^wp +F _t ^P2G +F ^ME +F ^BL +F ^XE (16)

F ^MT is the primary energy cost of natural gas consumed by cogeneration units during the dispatch period; F ^wp is the output cost of new energy abandoned during the dispatch period; F _t ^P2G represents the cost of power-to-gas conversion during the dispatch period; F ^BL represents the natural gas consumption of gas-fired boilers within the dispatch period Primary energy cost; F ^ME represents the operation and maintenance cost of all equipment in the micro-grid during the dispatch period; F ^EX represents the power purchase cost interacted with the large power grid within the dispatch period;

Among them, C _mi represents the unit maintenance cost of unit i; P _t ⁱ represents the output of unit _i in period t; C _buy and C _sell represent the electricity purchase price and electricity sale price ^respectively ; Interactive power, a positive value indicates electricity purchase, and a negative value indicates electricity sales to the large power grid.

Preferably, the comprehensive energy system of the park includes wind turbines, photovoltaic units, combined heat and power units, energy storage equipment, boilers and power-to-gas.

Preferably, the energy storage equipment includes a heat storage tank and battery energy storage; the boiler includes an electric boiler and a gas boiler.

Preferably, the output power of the wind power generation assembly is as follows:

In the formula, P _t ^wind is the fan output power, KW; v _ci , v _c0 , v _r are the cut-in wind speed, cut-out wind speed and rated wind speed, m/s; P _r is the rated output power, KW; a, b are Wind speed correlation coefficient;

The model of the volt generation component is expressed as:

P _t ^pv ＝ξCOSθη _m A _p η _p (4)

Among them, ξ represents the actual light radiation intensity; θ represents the angle of light incident on the solar panel; η _m represents the efficiency of the MPPT controller; A _P is the area of the solar panel; η _p represents the efficiency of the solar panel;

The cogeneration unit includes a micro cogeneration unit and a waste heat boiler; its thermoelectric relationship mathematical model is:

P_t ^MT、

分别表示时段t微燃机的排气余热量、电功率、发电效率；η_L为散热损失率；

表示时段t溴冷机制热量；C_oph、η_h分别表示溴冷机的制热系数和烟气回收率；In the formula,

P _t ^MT ,

Respectively represent the exhaust waste heat, electric power, and power generation efficiency of the micro-turbine at time period t; η _L is the heat dissipation loss rate;

Indicates the calorific value of the bromine refrigerator in time period t; C _oph and η _h represent the heating coefficient and flue gas recovery rate of the bromine refrigerator respectively;

The fuel cost of the micro-gas turbine in the time period t is:

Among them, Δt is the unit scheduling time, F ^MT is the fuel cost in the total scheduling period T; C _CH4 is the price of natural gas; L _MT is the low calorific value of natural gas.

The heat storage tank model is expressed as:

表示为时段t热储能的储热容量；μ表示为热储能的散热损失率；

表示为时段t内储热罐吸热、放热功率；η_hch、η_hdis表示为时段t内吸放热效率；in,

Expressed as the heat storage capacity of thermal energy storage in time period t; μ is expressed as the heat dissipation loss rate of thermal energy storage;

Expressed as the heat absorption and heat release power of the heat storage tank in the period t; _ηhch and _ηhdis are expressed as the heat absorption and release efficiency in the period t;

The relationship model between battery energy storage capacity and charging and discharging power is as follows:

表示为时段t电储能的储电容量；μ表示为电储能的损失率；P_t ^EES,in、P_t ^{EES ,dis}表示为时段t内蓄电池充电、放电功率；η_hch、η_hdis表示为时段t内充放电效率；in,

Expressed as the storage capacity of electric energy storage in period t; μ expresses the loss rate of electric energy storage; P _t ^EES,in , P _t ^{EES , dis} expresses the charging and discharging power of battery in period t; η _hch , η _hdis express is the charging and discharging efficiency in the time period t;

The electric boiler model is as follows:

P_t ^EB、η_EB分别为时段t电锅炉消耗电能和制热功率；η_EB表示电热转换效率，

分别表示为电锅炉最小制热功率与最大制热功率；In the formula

P _t ^EB , η _EB are the electric energy consumption and heating power of the electric boiler in period t respectively; η _EB represents the electrothermal conversion efficiency,

Respectively expressed as the minimum heating power and maximum heating power of the electric boiler;

The gas boiler model is as follows:

表示t时刻热电联产机组输出的热功率；η_BL表示燃气锅炉燃烧效率；

表示t时刻所消耗的天然气量；F^BL表示调度周期内消耗天然气能源成本；C_CH4表示天然气价格；In the formula,

Indicates the thermal power output by the combined heat and power unit at time t; η _BL indicates the combustion efficiency of the gas-fired boiler;

Indicates the amount of natural gas consumed at time t; F ^BL indicates the energy cost of natural gas consumed in the scheduling period; C _CH4 indicates the price of natural gas;

The power-to-gas equipment model in period t is as follows:

α分别表示t时段电价和CO₂价格以及生成单位的天然气所需的CO₂系数；P_t ^P2G、

分别表示t时段电转气装置消耗的电功率和生成的天然气功率，两者关系如下式：In the formula:

α respectively represent the electricity price and CO ₂ price in period t and the CO ₂ coefficient required to generate a unit of natural gas; P _t ^P2G ,

respectively represent the electric power consumed by the power-to-gas plant and the natural gas power generated during the period t, and the relationship between the two is as follows:

In the formula: _ηeg is the efficiency of the power-to-gas equipment.

Preferably, the constraints include electric power balance constraints, output upper and lower limit constraints, energy storage constraints, slope climbing constraints, power-to-gas constraints, and heat-to-electricity ratio constraints.

Preferably, the electric power balance constraint:

The upper and lower limit constraints of the output:

分别为第i个微电源出力的最小值、最大值；In the formula:

are the minimum value and maximum value of the output of the i-th micro-power supply;

Energy storage constraints:

表示储能最小最大容量；In the formula:

Indicates the minimum and maximum capacity of energy storage;

Climbing Constraints:

In the formula: -r _di and r _ui are the rate limits of load shedding and loading of controllable output unit i in the dispatching period t, respectively;

Power-to-gas constraints:

表示电转气设备的出力上限；In the formula

Indicates the output upper limit of the power-to-gas equipment;

Thermoelectric ratio constraint:

K _pmin and K _pmax are the maximum and minimum values of the heat-to-electricity ratio of the micro-turbine.

Preferably, the output upper and lower limit constraints include wind power output upper and lower limit constraints, photovoltaic output upper and lower limit constraints, micro gas turbine output upper and lower limit constraints, and micro power output upper and lower limit constraints.

Preferably, the energy storage constraints include electric energy storage constraints and thermal energy storage constraints.

The present invention has following beneficial effect:

Through conversion units such as P2G equipment, combined heat and power units, and energy storage equipment, the coupling relationship between the power system and the natural gas network is strengthened, and the flexibility of the system is improved. Considering the power-to-gas unit can realize the complementary advantages of each unit in the system and improve the efficiency of the system. Energy utilization efficiency, coordination of power optimization within the network, more flexible operation of combined heat and power units, saving energy consumption costs of the comprehensive energy system.

The power-to-gas aggregation unit strengthens the connection between electricity, heat and gas networks, and converts electricity into natural gas during periods when electricity is surplus, electricity prices are low, and gas prices are high, effectively improving system operation economy and scheduling flexibility , strengthen the consumption of new energy, and reduce the curtailment of wind and light in the system.

When optimizing the comprehensive system of the park, considering the power-to-gas unit can realize the complementary advantages of each unit in the system, improve energy utilization efficiency, coordinate the optimization of power supply in the network, make the combined heat and power unit operate more flexibly, and save the energy consumption cost of the comprehensive energy system.

Description of drawings

Fig. 1 is the operational structural diagram of the park integrated energy system of the present invention;

Fig. 2 is the relevant operating parameters of the park integrated energy system of the present invention;

Fig. 3 shows the parameters of the energy storage system of the present invention.

Fig. 4 is the wind power prediction curve of the present invention;

Fig. 5 is the prediction curve of photovoltaic output of the present invention;

Fig. 6 is the electric heating load prediction curve of the present invention;

Fig. 7 is the energy utilization efficiency of different modes of the present invention, the amount of new energy discarded;

Fig. 8 is a distribution diagram of energy utilization efficiency and new energy discarded amount in different modes of the present invention;

Fig. 9 is the actual output curve of the new energy under different operating modes of the present invention;

Fig. 10 is the analysis of system operation cost under different modes of the present invention;

Figure 11 is a comparative analysis of the output of each unit under different operating modes of the present invention.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

On the basis of the existing research, firstly, the basic principle of the power-to-gas technology and the advantages of absorbing new energy are analyzed; secondly, the establishment includes wind power, photovoltaic, cogeneration units, waste heat boilers, energy storage equipment, power-to-gas, And the comprehensive energy system model of combined heat and power parks composed of electric and heat loads, with the objective function of minimizing the comprehensive operating cost of the system. The example simulation shows that considering the power-to-gas technology can effectively reduce the curtailment of wind and light, reduce the operating cost of the system, improve the efficiency of energy utilization, and realize the environmental protection and economic operation of the system.

Power-to-gas technology:

Power-to-gas technology refers to the use of intermittent new energy sources such as abandoned wind and light, or the surplus power of the power grid during low-load periods to electrolyze water to produce hydrogen, and use the produced hydrogen and carbon dioxide to generate methane gas through the methanation reaction of the catalyst, realizing the power system and natural gas. system interconnection. Hydrogen production by electrolysis of water and methanation reaction have been studied by relevant scholars in the power industry and chemical industry respectively, but it is still in its infancy to combine the two as a whole to provide services for the power system and natural gas system.

Power-to-gas technology generates H2 and O2 by electrolyzing water, and then methanates H2 and CO2 to generate CH4. The CH4 generated by P2G conversion can be directly injected into the natural gas network for transportation, storage, and end-user use. On the other hand, because P2G electrolyzed water is not limited by the environment and time, it can be used to generate electricity during wind and solar abandonment and low-load periods. Used to electrolyze water to produce hydrogen, this technology plays an important role in accommodating abandoned wind and light, and accepting uncertain and intermittent renewable energy output.

Power-to-gas is divided into two stages. The first stage is the stage of electrolysis of water. Hydrogen is produced by electrolyzing water with new energy sources such as municipal electricity, wind power, and photovoltaics, and then the hydrogen is methanated with carbon dioxide to generate methane, which is fed into the natural gas network. , The natural gas generated by power-to-gas can be used as fuel for natural gas vehicles, and can also be supplied to cogeneration units for power generation or gas boilers to achieve cogeneration of electricity/gas/heat/cooling, and used as residential gas loads. Power-to-gas converts electrical energy into chemical energy, which is divided into two categories: power-to-hydrogen and power-to-natural gas. Among them, power-to-hydrogen generates hydrogen and oxygen through electrolysis of water. The chemical formula is as follows:

Due to the difficulty of storing and transporting hydrogen, power-to-natural gas is usually used. Electric-to-natural gas is based on the electrolysis of hydrogen, and generates methane through the chemical reaction of _CO2 and _H2 under certain circumstances. Therefore, P2G technology provides a new energy storage method for the power system, which can deepen the coupling between the power system and the natural gas system, and enhance the ability of the power system to accept intermittent renewable energy power generation. Its chemical expression can be expressed as:

CO ₂ +4H ₂ →CH ₄ +2H ₂ O (2)

The energy conversion efficiency in the process of electricity-to-hydrogen is 75%-85%, and the energy conversion efficiency in the process of methanation is also 75%-85%. After the two-stage chemical reaction, the comprehensive efficiency of electricity-to-natural gas is 45%-60%. between.

The network mainly includes wind turbines, photovoltaic generators, micro-gas turbines, electric boilers, electric energy storage, thermal energy storage, power-to-gas, gas boilers, electric loads, and thermal loads.

Wind turbine model:

The output power of the wind turbine is as follows:

In the formula, P _t ^wind is the fan output power, KW; v _ci , v _c0 , v _r are the cut-in wind speed, cut-out wind speed and rated wind speed, m/s; P _r is the rated output power, KW; a, b are Wind speed correlation coefficient.

Photovoltaic generator model:

The physical model of photovoltaics is usually expressed as:

P _t ^pv ＝ξCOSθη _m A _p η _p (4)

Among them, ξ represents the actual light radiation intensity; θ represents the angle of light incident on the solar panel; η _m represents the efficiency of the MPPT controller; _AP is the area of the solar panel; η _p represents the efficiency of the solar panel.

Combined heat and power unit model:

The core devices of cogeneration units are micro cogeneration units and waste heat boilers. The high-grade thermal energy of natural gas combustion drives the micro-turbine to generate electricity, and the high-temperature waste heat exhaust gas is heated by the waste heat recovery device and supplied with domestic hot water, which improves energy utilization efficiency. The mathematical model of its thermoelectric relationship is:

P_t ^MT、

分别表示时段t微燃机的排气余热量、电功率、发电效率；η_L为散热损失率；

表示时段t溴冷机制热量；C_oph、η_h分别表示溴冷机的制热系数和烟气回收率。In the formula,

P _t ^MT ,

Respectively represent the exhaust waste heat, electric power, and power generation efficiency of the micro-turbine at time period t; η _L is the heat dissipation loss rate;

Indicates the calorific value of the bromine cooler in time period t; C _oph and η _h represent the heating coefficient and flue gas recovery rate of the bromine cooler, respectively.

The fuel cost of the micro-gas turbine in the time period t is

Among them, Δt is the unit dispatch time, F ^MT is the fuel cost in the total dispatch period T; C _CH4 represents the price of natural gas, which is 2.5 yuan/cubic meter; L _MT represents the low calorific value of natural gas, which is 9.7kW·h/m ³ .

Heat storage tank model:

The heat storage tank plays an important role in stabilizing the fluctuation of new energy output, and has an irreplaceable position in the comprehensive energy system. The characteristics of the heat storage tank can be described as several parts of the relationship between the equipment's own capacity, input and output capabilities, and thermal efficiency. Its dynamic mathematical model can be expressed as:

表示为时段t热储能的储热容量；μ表示为热储能的散热损失率；

表示为时段t内储热罐吸热、放热功率；η_hch、η_hdis表示为时段t内吸放热效率。in,

Expressed as the heat storage capacity of thermal energy storage in time period t; μ is expressed as the heat dissipation loss rate of thermal energy storage;

Expressed as the heat absorption and heat release power of the heat storage tank in the period t; _ηhch and _ηhdis are expressed as the heat absorption and release efficiency in the period t.

Battery energy storage model:

The electric energy storage in the microgrid can realize the peak load shifting and valley filling of the electric load to absorb more new energy. The relationship model between the energy storage capacity of the battery and the charging and discharging power is as follows:

表示为时段t电储能的储电容量；μ表示为电储能的损失率；P_t ^EES,in、P_t ^EES,dis表示为时段t内蓄电池充电、放电功率；η_hch、η_hdis表示为时段t内充放电效率。in,

Expressed as the storage capacity of electric energy storage in period t; μ expresses the loss rate of electric energy storage; P _t ^EES,in , P _t ^EES,dis express the battery charging and discharging power in period t; η _hch , η _hdis express is the charging and discharging efficiency in the time period t.

Electric boiler model:

The electric boiler is a typical electric-thermal coupling equipment, which consumes electric energy to generate heat energy to meet the heat load and heat storage tank demand. Under the guidance of the time-of-use electricity price, the electric boiler cooperates with the cogeneration system to meet the heat load demand and increase the electricity consumption during the off-peak period. , so the introduction of electric boilers can realize electric-heat conversion and coordinate electric-heat loads. The typical output model is:

P_t ^EB、η_EB分别为时段t电锅炉消耗电能和制热功率；η_EB表示电热转换效率，

分别表示为电锅炉最小制热功率与最大制热功率。In the formula

P _t ^EB , η _EB are the electric energy consumption and heating power of the electric boiler in period t respectively; η _EB represents the electrothermal conversion efficiency,

Respectively expressed as the electric boiler minimum heating power and maximum heating power.

Gas boiler:

Gas-fired boilers consume natural gas as primary energy to generate heat energy, which is used as a supplementary heat source for cogeneration units. The output expression model between the heat energy and the natural gas used is as follows [19]:

表示t时刻热电联产机组输出的热功率；η_BL表示燃气锅炉燃烧效率；F_t ^BL表示t时刻所消耗的天然气量；F^BL表示调度周期内消耗天然气能源成本；C_CH4表示天然气价格；In the formula,

Indicates the thermal power output by the combined heat and power unit at time t; η _BL indicates the combustion efficiency of the gas-fired boiler; F _t ^BL indicates the amount of natural gas consumed at time t; F ^BL indicates the energy cost of natural gas consumed during the scheduling period; C _CH4 indicates the price of natural gas;

Power-to-gas model:

The operating cost of a P2G device includes two parts: fixed cost and variable cost. The fixed cost includes the cost of daily equipment maintenance, labor and other costs. The variable cost refers to the cost required for converting natural gas, which has a direct impact on the optimization results. The P2G operating costs mentioned in this article refer to variable costs, including electricity costs and raw material costs. The cost of electricity refers to the power consumption of the power-to-gas device, and the cost of raw materials is the cost of CO2.

Therefore, the operating cost of P2G devices in period t can be expressed by the following formula:

α分别表示t时段电价和CO2价格以及生成单位的天然气所需的CO2系数；P_t ^P2G、

分别表示t时段电转气装置消耗的电功率和生成的天然气功率，两者具有一定的关系，如下式：In the formula:

α respectively represent the electricity price and CO2 price in period t and the CO2 coefficient required to generate a unit of natural gas; P _t ^P2G ,

Respectively represent the electric power consumed by the power-to-gas plant and the natural gas power generated by the power-to-gas device during the t period, and the two have a certain relationship, as follows:

In the formula: _ηeg is the efficiency of the P2G device.

Objective function:

The optimization objectives of the integrated energy system include the cost of natural gas consumed by combined heat and power cogeneration units, the cost of natural gas consumed by gas-fired boilers, the cost of power-to-gas operation, the cost of new energy abandonment, and the operation and maintenance costs of each equipment unit, so that the comprehensive energy system of the park The total operating cost is minimal.

The economic objective function of the integrated energy system of the park is:

F ^MT is the primary energy cost of natural gas consumed by cogeneration units during the dispatch period; F ^wp is the output cost of new energy abandoned during the dispatch period; F _t ^P2G represents the cost of power-to-gas conversion during the dispatch period; F ^BL represents the natural gas consumption of gas-fired boilers within the dispatch period Primary energy cost; F ^ME represents the operation and maintenance cost of all equipment in the micro-grid during the dispatch period; F ^EX represents the power purchase cost interacted with the large power grid within the dispatch period;

Among them, C _mi represents the unit maintenance cost of unit i; P _t ⁱ represents _the output of unit i in period t; C _buy and C _sell represent the electricity purchase price and electricity sale price ^respectively ; Interactive power, a positive value indicates electricity purchase, and a negative value indicates electricity sales to the large power grid.

Restrictions:

1) System electrical power balance constraints:

2) The upper and lower limits of wind power, photovoltaics, micro gas turbines, and micro power sources:

分别为第i个微电源出力的最小值、最大值。In the formula:

are the minimum and maximum values of the output of the i-th micro-power supply, respectively.

3) Electric energy storage and thermal energy storage constraints:

表示热储能最小最大容量。In the formula:

Indicates the minimum and maximum capacity of thermal energy storage.

5) The climbing of the controllable unit is about:

In the formula: -r _di and r _ui are the rate limits of load shedding and loading of controllable output unit i in the dispatching period t, respectively.

6) Power-to-gas constraints;

Through the above discussion, the operating cost of the P2G device is closely related to the electricity price and CO2 price. Therefore, P2G has a direct impact on system scheduling.

表示P2G装置的出力上限。In the formula

Indicates the upper limit of the output of the P2G device.

7) Constraints on heat-to-electricity ratio of micro-turbine;

K _pmin and K _pmax are the maximum and minimum values of the heat-to-electricity ratio of the micro-turbine.

Example:

Select the comprehensive energy system of a park in a certain area of my country. The scheduling time is 24 hours a day, and the unit scheduling time is 1 hour. All the flue gas discharged from the micro-turbine is sent to the waste heat boiler. Figure 2 shows the operation and maintenance costs of each unit of the integrated energy system, and Figure 3 shows the relevant parameters of the energy storage system. Figure 4 shows the system electricity and thermal load curves and the joint forecast output curves of wind power and photovoltaics. The electricity purchase price connected to the grid is 1.2 yuan/kWh; the electricity sales price is 0.7 yuan/kWh. References for heat-to-electricity ratio constraints [Chen Zhuoyu, Wang Dan, Jia Hongjie, et al. Considering P2G multi-source energy storage type microgrid day-ahead optimal economic scheduling strategy research [J]. Chinese Journal of Electrical Engineering, 2017,37(11):3067 -3077+33626.]. The internal parameters of the system are shown in Figure 2, and the parameters of the energy storage system are shown in Figure 3.

In order to verify that the comprehensive energy system considers the advantages of power-to-gas technology in absorbing new energy and reducing operating costs, the following comparison scenarios are set up for comparison:

Method 1: Power-to-gas technology is not considered

Mode 2: Considering power-to-gas technology

Result analysis:

Analysis of new energy consumption and energy utilization efficiency under different operating modes. It can be seen from Figure 7-9 that in the comprehensive energy The utilization efficiency is 83.93%, the new energy abandonment rate (abandoned wind and light) is 26.4%, the energy utilization efficiency of mode 2 is increased to 95.39%, and the new energy abandonment rate (abandoned wind and light) is reduced to 10.8%. , can improve the absorption of new energy and the efficiency of energy utilization.

Analysis of system operating costs in different modes: As can be seen from Figures 10 and 11, the total operating cost of the system in mode 2 is 12394.2 yuan, which is 1708.2 yuan lower than that in mode 1. After considering the power-to-gas device, the comprehensive The energy system can effectively improve the flexibility of cogeneration units. It can be seen from Figure 11 that the cost of power-to-gas conversion in Mode 2 increases casually, but the flexibility between units in the comprehensive energy system is improved after the power-to-gas conversion is added. Electricity is used for power-to-gas conversion, which increases the consumption of new energy sources. The natural gas generated can also be used as cogeneration gas units and gas boilers in the system, and the comprehensive energy utilization efficiency of the park has been greatly improved.

To sum up, adding power-to-gas units in integrated energy system management can effectively improve energy utilization efficiency, reduce system operating costs, improve the stability of combined heat and power units, and make room for new energy output, which is " It provides an effective way to provide energy saving and emission reduction under the "double carbon" goal.

in conclusion

1) As a new energy conversion and storage method, P2G technology provides a new way for the consumption of renewable energy. Through conversion units such as P2G equipment and combined heat and power units, the coupling relationship between the power system and the natural gas network is strengthened. Improved system flexibility.

2) The electricity-to-gas aggregation unit strengthens the connection between electricity, heat and gas networks, and converts electricity into natural gas during periods when electricity is surplus, electricity prices are low, and gas prices are high, effectively improving system operation economy and dispatching Flexibility strengthens the consumption of new energy and reduces the curtailment of wind and light in the system.

3) When optimizing the comprehensive system of the park, considering the power-to-gas unit can realize the complementary advantages of each unit in the system, improve energy utilization efficiency, coordinate the optimization of power supply in the network, make the combined heat and power unit operate more flexibly, and save the energy consumption of the comprehensive energy system cost.

The above is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the description of the present invention and the contents of the accompanying drawings, or directly or indirectly used in other related technologies fields, all of which are equally included in the scope of patent protection of the present invention.

Claims (8)

1. A source and load storage coordination optimization scheduling method for a park comprehensive energy system is characterized by comprising the following steps: the method comprises the following steps:

constructing a park comprehensive energy system containing electricity-to-gas, a wind turbine generator, a photovoltaic generator, a cogeneration generator and an energy storage device electricity-heat-gas;

considering the electricity-to-gas participation in a natural gas trading market and an electric power trading market of the park comprehensive energy system, and establishing an optimized scheduling model;

the optimized scheduling model comprises constraint conditions and an objective function, and under the constraint of the constraint conditions, the system operation optimized scheduling model takes the lowest total cost of the system as the objective function to solve the optimal solution of the optimization result;

the objective function is:

Min F＝F ^MT +F ^wp +F _t ^P2G +F ^ME +F ^BL +F ^XE (16)

F ^MT the cost of consuming primary energy of natural gas for the cogeneration unit in the scheduling period; f ^wp Abandoning the new energy output cost in the dispatching period; f _t ^P2G Representing the cost of converting the dispatching cycle into electricity to gas; f ^BL Representing the primary energy cost of natural gas consumed by the gas boiler in the dispatching period; f ^ME Representing the operation and maintenance cost of all the devices in the microgrid in the scheduling period; f ^EX Representing the electricity purchase cost interacted with a large power grid in a dispatching period;

wherein, C _mi Represents the unit maintenance cost of the unit i; p _t ⁱ Represents the output of time t unit i; c _buy ,C _sell Respectively showing the electricity purchasing price and the electricity selling price; p _t ^ex And the interactive power of the microgrid and the large power grid in the period t is represented, a positive value represents electricity purchasing, and a negative value represents electricity selling to the large power grid.

2. The source-load-storage coordination optimization scheduling method of the park integrated energy system according to claim 1, characterized in that: the park comprehensive energy system comprises a wind turbine generator, a photovoltaic generator, a cogeneration generator, energy storage equipment, a boiler and electricity-to-gas conversion.

3. The source-storage coordination optimization scheduling method for the park integrated energy system according to claim 2, characterized in that: the energy storage equipment comprises a heat storage tank and a storage battery for storing energy; the boiler includes an electric boiler and a gas boiler.

4. The source-load-storage coordination optimization scheduling method of the park integrated energy system according to claim 3, characterized in that:

the output power of the wind power generation assembly is as follows:

in the formula, P _t ^wind Is the output power of the fan, KW; v. of _ci ，v _c0 ，v _r Respectively the cut-in wind speed, the cut-out wind speed and the rated wind speed, m/s; p is _r Rated output power, KW; a and b are wind speed correlation coefficients;

the model of the photovoltaic power generation assembly is represented as:

P _t ^pv ＝ξCOSθη _m A _p η _p (4)

where ξ represents the actual illumination radiation intensity; θ represents an angle of incidence of the illumination to the solar panel; eta _m Representing the efficiency of the MPPT controller; a. The _P Is the area of the solar panel; eta _p Representing the efficiency of the solar panel;

the cogeneration unit comprises a micro cogeneration unit and a waste heat boiler; the mathematical model of the thermoelectric relationship is as follows:

in the formula,

P _t ^MT 、

respectively representing exhaust waste heat, electric power and power generation efficiency of the micro-combustion engine in a time period t; eta _L The heat dissipation loss rate;

representing the heating capacity of the bromine refrigerator in a time period t; c _oph 、η _h Respectively representing the heating coefficient and the flue gas recovery rate of the bromine refrigerator;

the fuel cost of the micro-combustion engine in the time period t is as follows:

where Δ t is the unit scheduling time, F ^MT Scheduling the fuel cost in the total period T; c _CH4 Representing the natural gas price; l is _MT Indicating a low heating value of natural gas.

The heat storage tank model is represented as:

wherein,

heat storage capacity expressed as heat storage over time period t; mu is expressed as the heat dissipation loss rate of heat storage;

the heat absorption and release power of the heat storage tank in a time period t is represented; eta _hch 、η _hdis Expressed as heat absorption and release efficiency over time period t;

the relation model of the storage battery energy storage capacity and the charge-discharge power is as follows:

wherein,

a storage capacity expressed as electrical energy storage over a time period t; mu is expressed as the loss rate of the electrical energy storage; p _t ^EES,in 、P _t ^EES,dis The charging and discharging power of the storage battery in a time period t is expressed; eta _hch 、η _hdis Expressed as the charging efficiency in time period t;

the electric boiler model is as follows:

in the formula

P _t ^EB 、η _EB Electric energy consumption and heating power of the electric boiler are respectively in a time period t; eta _EB The efficiency of the electric-to-heat conversion is shown,

respectively expressed as the minimum heating power and the maximum heating power of the electric boiler;

the gas boiler model is as follows:

in the formula,

the thermal power output by the cogeneration unit at the moment t is represented; eta _BL Representing the combustion efficiency of the gas boiler; f _t ^BL Representing the amount of natural gas consumed at time t; f ^BL Representing the cost of natural gas energy consumed in the scheduling period; c _CH4 Representing the natural gas price;

the electric gas conversion equipment model in the period t is as follows:

in the formula:

alpha represents the electricity price and CO respectively in the period t ₂ Price and CO required to produce a unit of natural gas ₂ A coefficient; p _t ^P2G 、

Respectively representing the consumed electric power and the generated natural gas power of the electric gas conversion device in the period t, and the relationship between the consumed electric power and the generated natural gas power is as follows:

in the formula: eta _eg The efficiency of the electric gas conversion equipment.

5. The source-storage coordination optimization scheduling method for the park integrated energy system according to claim 4, characterized in that: the constraint conditions comprise electric power balance constraint, output upper and lower limit constraint, energy storage constraint, climbing constraint, electric-to-gas constraint and thermoelectric ratio constraint.

6. The energy system source-charge-storage coordination optimization scheduling method considering electricity to gas as claimed in claim 5, characterized in that:

the electric power balance constraint is:

P _t ^ex +P _t ^wp +P _t ^MT +P _t ^HS,dis ＝P _t ^load +P _t ^EB +P _t ^HS,in (20)

and (3) restraining the upper and lower output limits:

in the formula:

the minimum value and the maximum value of the output of the ith micro power source are respectively;

energy storage restraint:

in the formula:

representing a minimum maximum capacity of stored energy;

and (3) climbing restraint:

in the formula: -r _di 、r _ui Respectively is the speed limit value of load shedding and load loading of the controllable output unit i in the scheduling t period;

electric-to-gas restraint:

in the formula

Representing the upper limit of the output of the electric gas conversion equipment;

thermoelectric ratio constraint:

K _pmin ，K _pmax the maximum and minimum thermoelectric ratios of the micro-combustion engine are obtained.

7. The source-load-storage coordination optimization scheduling method of the park integrated energy system according to claim 6, characterized in that: the output upper and lower limit constraints comprise wind power output upper and lower limit constraints, photovoltaic output upper and lower limit constraints, micro gas turbine output upper and lower limit constraints and micro power source output upper and lower limit constraints.

8. The source-load-storage coordination optimization scheduling method of the park integrated energy system according to claim 6, characterized in that: the energy storage constraints include electrical energy storage constraints and thermal energy storage constraints.

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