Elastic load and photovoltaic coordinated dispatching method based on coal mine production characteristic constraint

Abstract

The invention discloses an elastic load and photovoltaic coordinated scheduling method based on coal mine production characteristic constraints. The method comprises the following steps: establishing an elastic load model based on the coal mine production characteristic constraints; constructing a constraint relation based on an elastic load model; and constructing an elastic load and photovoltaic coordinated dispatching operation objective function, performing calculation and solution, obtaining a day-ahead operation state power curve of the elastic load, and performing coordinated dispatching of the elastic load and photovoltaic power generation at different moments. According to the method, the matching degree of mine area photovoltaic power generation and the coal mine source load is improved by combining the dispatching space of the coal mine elastic load, daytime source load curve fitting is achieved, the equipment operation states at different moments are further adjusted through the peak and valley electricity prices, the peak and valley period adjustment of the coal mine load, the efficient photovoltaic consumption and the coal mine low-carbon production can be achieved, and the economic benefit is improved. And a theoretical basis and data support can be provided for low-carbon optimal coupling of photovoltaic power generation in a mining area and coal mine source load.

Description

Technical Field

[0001] The present invention relates to an energy optimization scheduling method, specifically a coordinated scheduling method for flexible load and photovoltaic based on the constraints of coal mine production characteristics, belonging to the technical field of low-carbon energy production. Background Technique

[0002] China is rich in coal resources, and coal is one of the main energy sources in China. According to the 2021 National Economic and Social Development Statistical Bulletin of China, the coal consumption in China accounts for 56% of the total energy consumption. Coal mining includes multiple links such as excavation, transportation, drainage, and ventilation. The industry has characteristics such as high energy consumption, high energy consumption cost, and strong dependence on fossil energy. How to achieve energy-saving and economic production in coal mines is an issue of concern in the industry.

[0003] Coal mining is a combination of energy consumption and production capacity. There are multi-energy demands of electricity - heat - cold in the coal mining process. On the one hand, the energy consumption in the coal mining link is large. The links of coal mining, transportation, ventilation, drainage, and heating usually operate in a constant state, resulting in difficult energy supply-demand matching due to low supply-demand matching degree between the source and load during the day, low energy utilization efficiency, and easy waste of a large amount of energy resources. Taking the ventilation system as an example, within the same coal production shift, the ventilation fan operates at a relatively constant power, and the air volume sent often exceeds the sum of the actual required air volume and the standby air volume, resulting in unnecessary energy consumption. On the other hand, although the operation of drainage pumps, ventilation fans, and other energy conversion equipment will generate associated energy such as coal mine water inrush, exhausted air, and equipment waste heat, which can be "turned waste into treasure" through technologies such as power generation and heat pumps, with the extension of underground working face mining and the change of geological environment, the amount of associated energy gushing out is difficult to predict, and the utilization effect of associated energy is not ideal.

[0004] Compared with the above traditional new energy in mining areas, photovoltaic power generation has developed into the first choice for the construction of new energy in many mining areas due to its characteristics such as pollution-free and no carbon emissions. However, the output of photovoltaic power generation is greatly affected by factors such as light intensity and temperature, with high randomness and volatility, increasing the difficulty of source-load matching during the day and prone to light curtailment phenomenon, and the utilization effect of photovoltaic power generation in mining areas is not ideal. How to improve the matching degree between photovoltaic power generation in mining areas and coal mine source-load, reduce the waste of resources and energy, and achieve low-carbon and efficient operation of coal mines is an urgent problem to be solved in the industry. Summary of the Invention

[0005] Aiming at the problems existing in the above-mentioned prior art, the present invention provides a coordinated scheduling method for flexible load and photovoltaic based on the constraints of coal mine production characteristics, which can improve the matching degree between photovoltaic power generation in mining areas and coal mine source-load, reduce the waste of resources and energy, and achieve low-carbon and efficient operation of coal mines, and can provide a theoretical basis and data support for the optimal coupling of low-carbon photovoltaic power generation in mining areas and coal mine source-load.

[0006] To achieve the above object, the elastic load and photovoltaic coordinated scheduling method based on coal mine production characteristic constraints specifically includes the following steps:

[0007] Step1. Based on the constraints of coal mine production characteristics, establish an elastic load model. The elastic load model includes a strong safety constraint elastic load model and a non-strong safety constraint elastic load model. The strong safety constraint elastic load model includes an elastic load model for the mining and transportation links, a ventilation elastic load model, and an underground drainage elastic load model. The non-strong safety constraint elastic load model includes a water source heat pump elastic load model and a wellhead heat preservation elastic load model;

[0008] Step2. Based on the elastic load model, determine the known parameters and decision variables, and construct the constraint relationship;

[0009] ① The upper and lower limits of elastic load power consumption are expressed as follows:

[0010] 0 ≤ P t ≤ P max

[0011] In the formula: P t is the electric power of the elastic load at time t, kW; P max is the maximum operating electric power of the elastic load, kW.

[0012] ② Elastic load ramp constraint

[0013] To avoid the switching between the stop operation state and the high-power operation state of the elastic load at adjacent operation times, the ramp power of the elastic load is restricted. The elastic load ramp constraint is expressed as follows:

[0014] -η p P max ≤ P t+1 -P t ≤ η p P max

[0015] In the formula: η p is the elastic load ramp ratio, %; P t+1 is the electric power of the elastic load at time t + 1, kW.

[0016] ③ The power balance constraint of the energy system is expressed as follows:

[0017] P grid,t + P gen,t =P load,t

[0018] H buy,t + H gen,t =H load,t

[0019] In the formula: Pgrid,t is the purchased electric power at time t, in kW; P gen,t is the power generation of the system's own power generation equipment at time t, in kW; P load,t is the total power of the electrical load of all electrical equipment at time t, in kW; H buy,t is the purchased heat power at time t, in kW; H gen,t is the heating power of the system's own heating equipment at time t, in kW; H load,t is the total heat load power of all heat power demands at time t, in kW;

[0020] Step3. Construct the coordinated scheduling operation objective function of the flexible load and photovoltaic, and perform calculation and solution to obtain the power curve of the flexible load's daily operation state, and conduct coordinated scheduling of the flexible load and photovoltaic power generation at different times;

[0021] The coordinated scheduling operation objective function of the flexible load and photovoltaic is expressed as follows:

[0022] Z = β grid P grid + β pv P pv + β gas GAS

[0023] In the formula: Z is the total carbon emissions of the system operation, in tCO 2 ; β grid is the carbon emissions per unit of the power grid, in tCO 2 / kWh; β pv is the carbon emissions per unit of photovoltaic power generation, in tCO 2 / kWh; β gas is the carbon emissions per unit of natural gas, in tCO 2 / MJ; P grid is the total purchased electric energy, in kWh; P pv is the total photovoltaic power, in kWh; GAS is the total calorific value of natural gas, in MJ.

[0024] Furthermore, in Step1, the flexible load model in the mining and transportation link includes the flexible load model of the shearer, the flexible load model of the belt conveyor, and the flexible load models of the underground and surface coal bunkers. Specifically:

[0025] ① The flexible load model of the shearer is expressed as follows:

[0026]

[0027]

[0028] In the formula: is the operating power of the shearer at time t, in kW; is the traction speed of the shearer at time t, m / s; θ is a coefficient related to the structural parameters of the shearer (according to standard ISO5048); is the maximum value of the shearer traction speed, m / s;

[0029] ② The elastic load model of the belt conveyor is expressed as follows:

[0030]

[0031]

[0032] 0 ≤ v t ≤ v max

[0033] Where: is the average power of the belt conveyor in the t-th hour, kW; μ is a coefficient related to the structure of the belt conveyor (according to standard ISO5048); η d 、η m are the efficiencies of the motor and the drive system respectively, %; is the mass per unit length of the belt conveyor in the t-th time period, kg / m; v t is the transmission speed of the belt, m / s; W t is the throughput of the belt conveyor in the t-th time period, tons / h; v max is the maximum transmission speed of the belt, m / s; is the upper limit of the mass per unit length of the belt conveyor, kg / m;

[0034] ③ The elastic load model of the underground and surface coal bunkers is expressed as follows:

[0035] If the upper limit of the coal bunker capacity is set to 90% and the lower limit is set to 20%, then

[0036] C t+1 =C t + θ in,t - θ out,t

[0037] 0.2C N ≤ C t ≤ 0.9C N

[0038] Where: θ in,t 、θ out,t are the amounts of coal transported into and out of the coal bunker in the t-th hour respectively, tons; C N is the capacity of the coal bunker, tons; C t is the coal storage amount in the coal bunker in the t-th hour, tons.

[0039] Furthermore, in Step1, the ventilation elastic load model includes the air distribution calculation model and the ventilation fan elastic load model. Specifically:

[0040] ① The air distribution volume calculation model is expressed as follows:

[0041] Q P,i = K × (∑Q C,i + ∑Q J,i + ∑Q D,i + ∑Q H,i )

[0042] Where: Q P,i is the total air distribution volume, m 3 / h; K is the mine ventilation coefficient, with a value of 1.2; Q C,i is the air volume required for the coal mining face, m 3 / h; Q J,i is the air volume required for the tunneling face, m 3 / h; Q D,i is the air volume required for the independent air supply chamber, m 3 / h; Q H,i is the air volume required for other roadways, m 3 / h;

[0043] Q C = 125k c × q c

[0044] Where: 125 is the conversion coefficient; k c is the uneven coefficient of gas emission in the coal mining face, with a value of 2.5; q c is the relative gas emission volume in the coal mining face, m 3 / ton;

[0045] Q J = 100k J × q J

[0046] Where: 100 is the conversion coefficient; k J is the uneven coefficient of gas emission in the tunneling face, with a value of 2; q J is the relative gas emission volume in the tunneling face, m 3 / ton;

[0047] Q D = 80N D

[0048] Where: 80 is the average air distribution volume per single chamber, m 3 / h; N D is the number of chambers;

[0049] Q H = 133N H

[0050] Where: 133 is the conversion coefficient of gas emission from a single roadway; N H is the number of roadways;

[0051] ② The elastic load model of the ventilator is expressed as follows:

[0052] P TF,t = f(Q TF,t , p TF , η TF )

[0053] Q TF,t ≥ Q P

[0054] Where: P TF,t is the operating power of the ventilator at time t, kW; Q TF,t is the air intake of the ventilator at time t, m 3 / h; p TF is the total pressure of the fan, Pa; η TF is the operating efficiency of the ventilator, %.

[0055] Furthermore, in Step1, the elastic load model of underground drainage includes the elastic load model of underground drainage pumps and the elastic load model of underground water sumps. Specifically:

[0056] ① The elastic load model of underground drainage pumps is expressed as follows:

[0057] P X = f(κ, g, W X , h X , η X )

[0058] 0 ≤ W X ≤ W X，max

[0059] Where: X is the type of drainage pump; P X is the operating power of the X-type water pump, kW; κ is the specific gravity of the medium, kg / m 3 ; g is the acceleration of gravity, taking 9.8 N / kg; W X is the operating flow rate of the X-type water pump, m 3 / h; h X is the head of the X-type water pump, m; η X is the operating efficiency of the X-type water pump, %; W X，max is the maximum operating flow rate of the X-type water pump, m 3 / h;

[0060] ② The elastic load model of the underground water sump is expressed as follows:

[0061] The empty capacity of the water sump should be maintained at more than 50% of the total capacity, that is:

[0062] V EM ≥0.5V max

[0063] Where: V EM is the empty capacity of the sump, m 3 ; V max is the total capacity of the sump, m 3 .

[0064] Furthermore, in Step1, the elastic load model of the water source heat pump is expressed as follows:

[0065]

[0066] Where: P hepm,t is the electric power consumed by the water source heat pump unit within time period t, kW; H hepm,t is the heat output of the water source heat pump unit within time period t, kW; COP is the heating performance coefficient of the water source heat pump unit; H exch,t is the heat absorbed by the water source heat pump unit from the heat source side within time period t, kW; α is the specific heat capacity of the circulating working fluid, J / (kg·°C); ο is the mass flow rate of the circulating working fluid, kg / h; T in , T out are the inlet and outlet temperatures of the evaporator side of the water source heat pump, °C.

[0067] Furthermore, in Step1, the elastic load model of the wellhead heat preservation is expressed as follows:

[0068] H FD = f(Q TF,ave , ρ inair , C ENT , T mix , T low )

[0069] H FD,t ≥ H FD

[0070] Where: H FD is the basic heat power required for wellhead anti-freezing, kW; Q TF,ave is the average air inflow at the wellhead, m 3 / s; ρ inair is the air density, with a value of 1.28 kg / m 3 ; C ENT is the specific heat capacity at constant pressure of air, with a value of 1.01 kJ / (kg·°C); T mix is the temperature after mixing of hot and cold air, °C; T low is the lowest ambient temperature in winter, °C; H FD,t is the heat power required for wellhead anti-freezing at time t, kW.

[0071] Further, in Step 3, the Gurobi solver is used for calculation and solution.

[0072] Compared with the prior art, the elastic load and photovoltaic coordinated scheduling method based on the constraints of coal mine production characteristics combines the scheduling space of the coal mine elastic load, improves the matching degree of photovoltaic power generation in the mining area and the source and load of the coal mine, realizes the fitting of the source and load curves during the day, and further adjusts the operating states of equipment at different times through peak-valley electricity prices, so as to realize the adjustment of the peak and valley periods of the coal mine load, the efficient consumption of photovoltaic power, and the low-carbon production of the coal mine. After simulation verification, compared with the constant-state operation, although the energy purchase cost of the coordinated scheduling operation increases by 2,300 yuan, the CO 2 emission is reduced by 0.93887 tons, which can provide a theoretical basis and data support for the low-carbon optimal coupling of photovoltaic power generation in the mining area and the source and load of the coal mine. Description of the Drawings

[0073] Figure 1 is the flowchart of the present invention;

[0074] Figure 2 is the diagram showing the results of the coordinated scheduling of the coal mine elastic load and photovoltaic power in the embodiment of the present invention;

[0075] Figure 3 is the diagram showing the carbon dioxide emission situation of the coal mine in the embodiment of the present invention. Detailed Embodiment

[0076] The constraints of coal mine production characteristics mean that during the normal operation of the load, it is necessary to satisfy both the safety constraints stipulated by the coal mine safety regulations and its own operation constraints.

[0077] Elastic load refers to that on the basis of satisfying the constraints of coal mine production characteristics, there is a scheduling space for the load's electricity (heat) power demand or it can be in a start-stop operation state. Elastic loads are divided into two categories: strongly safety-constrained loads and non-strongly safety-constrained loads. Among them, strongly safety-constrained loads refer to those where there are mandatory safety requirements for the coal mine in the load itself or the production links involved, including loads in the mining and transportation links, ventilation loads, and underground drainage loads; non-strongly safety-constrained loads refer to those that only need to satisfy the operation requirements of their own or related production links, including water source heat pump loads and wellhead heat preservation loads.

[0078] The matching of photovoltaic power generation in the mining area and the source and load of the coal mine is to, on the basis of satisfying the constraints of coal mine production characteristics, the normal operation constraints of elastic loads, and the power balance constraints of the energy system, take the strategy of matching the peak and valley periods of elastic loads and photovoltaic power generation forecasts, and take the optimal low-carbon operation of the coal mine energy system as the goal, and obtain the daily operating power curve of the elastic load through solution, and conduct coordinated scheduling of elastic loads and photovoltaic power generation at different times.

[0079] The present invention is to establish an elastic load model for different loads respectively to reflect the relationship between variables and power, and to realize the coordinated scheduling of elastic load and photovoltaic power generation at different times by means of the scheduling space existing between variables and power during operation.

[0080] The following further describes the present invention with reference to the accompanying drawings.

[0081] The method for coordinated scheduling of elastic load and photovoltaic based on the constraints of coal mine production characteristics specifically includes the following steps:

[0082] Step1. Based on the constraints of coal mine production characteristics, establish an elastic load model.

[0083] The elastic load model includes a strong safety constraint elastic load model and a non-strong safety constraint elastic load model.

[0084] The strong safety constraint elastic load model includes an elastic load model for the mining and transportation link, a ventilation elastic load model, and an underground drainage elastic load model, which are specifically as follows:

[0085] The elasticity of the load in the mining and transportation link is reflected in that during operation, the coal mining speed of the shearer, the transportation speed and volume of the belt conveyor basically maintain a constant value within their own constraint ranges, and there is a scheduling space to increase or decrease the transportation speed (volume) or change the start-stop state according to the balance of system energy supply and demand and the coal storage volume in the coal bunker. Therefore, the elastic load model for the mining and transportation link includes an elastic load model for the shearer, an elastic load model for the belt conveyor, and an elastic load model for the underground and surface coal bunkers. Specifically:

[0086] ① The elastic load model of the shearer is expressed as follows:

[0087]

[0088] In the formula: is the operating power of the shearer at time t, in kW; is the traction speed of the shearer at time t, in m / s; θ is a coefficient related to the structural parameters of the shearer (in accordance with standard ISO5048); is the maximum value of the traction speed of the shearer, in m / s.

[0089] ② The elastic load model of the belt conveyor is expressed as follows:

[0090]

[0091]

[0092] 0≤v t ≤v max

[0093] In the formula: is the average power of the belt conveyor in the t-th hour, kW; μ is a coefficient related to the structure of the belt conveyor (according to the standard ISO5048); η d and η m are the efficiencies of the motor and the drive system respectively, %; is the mass per unit length of the belt conveyor in the t-th period, kg / m; v t is the transmission speed of the belt, m / s; W t is the throughput of the belt conveyor in the t-th period, tons / h; v max is the maximum transmission speed of the belt, m / s; is the upper limit of the mass per unit length of the belt conveyor, kg / m.

[0094] ③ The elastic load model of the underground and surface coal bunkers is expressed as follows:

[0095] If the upper limit of the coal bunker capacity is set to 90% and the lower limit is set to 20%, then

[0096] C t+1 = C t + θ in,t - θ out,t

[0097] 0.2C N ≤ C t ≤ 0.9C N

[0098] In the formula: θ in,t and θ out,t are the amounts of coal transported into and out of the coal bunker in the t-th hour respectively, tons; C N is the capacity of the coal bunker, tons; C t is the coal storage amount in the coal bunker in the t-th hour, tons.

[0099] The elasticity of the ventilation load is reflected in that the ventilator usually operates at a constant state with a power lower than the rated operating power and reserves more than 10% of the ventilation volume on the basis of meeting the actual underground air distribution requirements. There is a scheduling space for increasing or decreasing the ventilation volume (operating power) according to the underground ventilation requirements and the power balance of the energy system. Therefore, the ventilation elastic load model includes an air distribution calculation model and a ventilator elastic load model. Specifically:

[0100] ① The air distribution calculation model is expressed as follows:

[0101] Q P,i = K × (∑Q C,i + ∑Q J,i + ∑Q D,i + ∑Q H,i )

[0102] In the formula: Q P,i is the total air distribution, m 3 / h; K is the mine ventilation coefficient, with a value of 1.2; Q C,i is the air volume required for the coal mining face, m 3 / h; Q J,i is the air volume required for the heading face, m 3 / h; Q D,i is the air volume required for the independent air supply chamber, m 3 / h; Q H,i is the air volume required for other roadways, m 3 / h;

[0103] Q C = 125k c ×q c

[0104] In the formula: 125 is the conversion coefficient. Based on the gas concentration in the coal mining face should be lower than 0.8%, that is, 1 / 0.008; k c is the uneven gas emission coefficient in the coal mining face, with a value of 2.5; q c is the relative gas emission volume in the coal mining face, m 3 / ton, and the value is 5.78 according to the measurement on the project site;

[0105] Q J = 100k J ×q J

[0106] In the formula: 100 is the conversion coefficient, which is calculated based on the gas concentration in the heading face should be lower than 1%, that is, 1 / 0.01; k J is the uneven gas emission coefficient in the heading face, with a value of 2; q J is the relative gas emission volume in the heading face m 3 / ton, and the value is 2.24 according to the measurement on the project site;

[0107] Q D = 80N D

[0108] In the formula: 80 is the average air distribution volume for a single chamber, m 3 / h; N D is the number of chambers;

[0109] Q H = 133N H

[0110] In the formula: 133 is the conversion coefficient for the gas emission from a single roadway. It is calculated based on the gas concentration in the roadway should be lower than 0.75%, that is, 1 / 0.75; N H is the number of roadways.

[0111] ② The elastic load model of the ventilator is expressed as follows:

[0112] P TF,t = f(Q TF,t , p TF , η TF )

[0113] Q TF,t ≥ Q P

[0114] Where: P TF,t is the operating power of the ventilator at time t, in kW; Q TF,t is the air intake of the ventilator at time t, in m 3 / h; p TF is the total static pressure of the fan, in Pa; η TF is the operating efficiency of the ventilator, with a value of 0.9.

[0115] The elasticity of the underground drainage load is reflected in that the drainage pump operates at a constant flow rate (operating power) to meet the safety requirements of underground water storage. There is room for adjusting the flow rate (operating power) or changing the start / stop state according to the water storage volume in the underground water sump and the balance of system energy supply and use. Therefore, the underground drainage elastic load model includes the underground drainage pump elastic load model and the underground water sump elastic load model. Specifically:

[0116] ① The underground drainage pump elastic load model is expressed as follows:

[0117] P X = f(κ, g, W X , h X , η X )

[0118] 0 ≤ W X ≤ W X，max

[0119] Where: X is the type of drainage pump, divided into working, standby, and maintenance; P X is the operating power of the X-type water pump, in kW; κ is the specific gravity of the medium, taking 1000 kg / m 3 ; g is the acceleration due to gravity, taking 9.8 N / kg; W X is the operating flow rate of the X-type water pump, in m 3 / h; h X is the head of the X-type water pump, in m; η X is the operating efficiency of the X-type water pump, in %; W X，max is the maximum operating flow rate of the X-type water pump, in m 3 / h.

[0120] ② The underground water sump elastic load model is expressed as follows:

[0121] The empty tank capacity of the water sump should be kept above 50% of the total capacity, that is:

[0122] V EM ≥0.5V max

[0123] Where: V EM is the empty capacity of the sump, m 3 ; V max is the total capacity of the sump, m 3 .

[0124] The non-strong safety constraint elastic load model includes the water source heat pump elastic load model and the wellhead heat preservation elastic load model, specifically as follows:

[0125] The elasticity of the water source heat pump is reflected in that it usually operates at a constant heat output power state, and there is room for adjustment to increase or decrease the heat output power or change the start-stop state in cooperation with other heating equipment according to the energy supply and demand balance of the system. Therefore, the water source heat pump elastic load model is expressed as follows:

[0126]

[0127] Where: P hepm,t is the electric power consumed by the water source heat pump unit within the time period t, kW; H hepm,t is the heat output of the water source heat pump unit within the time period t, kW; COP is the heating performance coefficient of the water source heat pump unit; H exch,t is the heat absorbed by the water source heat pump unit from the heat source side within the time period t, kW; α is the specific heat capacity of the circulating working medium, J / (kg·°C); ο is the mass flow rate of the circulating working medium, kg / h; T in , T out are the inlet and outlet temperatures of the evaporator side of the water source heat pump, °C, respectively.

[0128] The elasticity of the wellhead anti-freezing load is reflected in that it usually operates at a constant state to meet the heat demand for wellbore heat preservation at the average ventilation volume, and there is a scheduling space to increase or decrease the heat power according to the actual demand for wellhead anti-freezing under the change of ventilation volume and the energy supply and demand balance of the system. Therefore, the wellhead heat preservation elastic load model is expressed as follows:

[0129] H FD = f(Q TF,ave , ρ inair , C ENT , T mix , T low )

[0130] H FD,t ≥H FD

[0131] Where: H FD is the basic heat power required for wellhead anti-freezing, kW; Q TF,ave is the average air intake at the wellhead, m 3 / s; ρinair is the air density, with a value of 1.28 kg / m 3 ; C ENT is the specific heat capacity of air at constant pressure, with a value of 1.01 kJ / (kg·°C); T mix is the temperature after mixing hot and cold air, °C; T low is the lowest ambient temperature in winter, °C; H FD,t is the heat power required for wellhead anti-freezing at time t, kW.

[0132] Step2. Based on the elastic load model, determine the known parameters and decision variables, and construct the constraint relationships. The constraint relationships are as follows:

[0133] ① The upper and lower limits of elastic load electricity consumption are expressed as follows:

[0134] 0 ≤ P t ≤ P max

[0135] In the formula: P t is the electric power of the elastic load at time t, kW; P max is the maximum operating electric power of the elastic load, kW.

[0136] ② Elastic load ramp constraint

[0137] To avoid the switching between the stopped operation state and the high-power operation state of the elastic load at adjacent operation times, the ramp power of the elastic load is restricted. The elastic load ramp constraint is expressed as follows:

[0138] -η p P max ≤ P t+1 -P t ≤ η p P max

[0139] In the formula: η p is the elastic load ramp ratio, %; P t+1 is the electric power of the elastic load at time t + 1, kW.

[0140] ③ The power balance constraint of the energy system is expressed as follows:

[0141] P grid,t + P gen,t =P load,t

[0142] H buy,t + H gen,t =H load,t

[0143] In the formula: P grid,t is the purchased electric power at time t, kW; P gen,tis the power generation power of the system's own power generation equipment at time t, in kW; P load,t is the total electrical load power of all electrical equipment at time t, in kW; H buy,t is the purchased heat power at time t, in kW; H gen,t is the heating power of the system's own heating equipment at time t, in kW; H load,t is the total heat load power of all heat power demands at time t, in kW.

[0144] Step3. Construct the coordinated scheduling operation objective function of flexible load and photovoltaic, and use the Gurobi solver for calculation and solution.

[0145] On the basis of meeting the flexible load model and constraint relationships, combined with peak-valley electricity prices, use the scheduling space of flexible load to adjust the peak-valley period of load energy consumption, match it with the day-ahead prediction result of photovoltaic power generation, and take the optimal low-carbon operation of the coal mine energy system as the goal. Through solution, obtain the power curve of the day-ahead operation state of flexible load to carry out the coordinated scheduling of flexible load and photovoltaic power generation at different times.

[0146] The coordinated scheduling operation objective function of flexible load and photovoltaic is expressed as follows:

[0147] Z = β grid P grid + β pv P pv + β gas GAS

[0148] In the formula: Z is the total carbon emissions of system operation, in tCO 2 , that is, in tons of CO 2 is the unit carbon emissions of the power grid, in tCO grid / kWh; β 2 is the unit carbon emissions of photovoltaic power generation, in tCO pv / kWh; β 2 is the unit carbon emissions of natural gas, in tCO gas / MJ; P 2 is the total purchased electricity, in kWh; P grid is the total photovoltaic power, in kWh; GAS is the total calorific value of natural gas, in MJ. pv

[0149] The following takes the operation data of a certain coal mine in Shanxi as a reference for simulation, uses MATLAB_R2021b to call the Gurobi10.0.1 solver for simulation and solution, and the load changes before and after system scheduling, purchased electricity, photovoltaic, etc. after scheduling are as Figure 2 shown, and the carbon emissions of purchased electricity, photovoltaic, and natural gas after scheduling are as Figure 3 ​As shown. Through simulation analysis, the comparison results of the low-carbon optimization of the coordinated scheduling of elastic load and photovoltaic are shown in Table 1 below. Compared with the constant-state operation, although the energy purchase cost of the coordinated scheduling operation increases by 2,300 yuan, the CO 2 emission is reduced by 0.93887 tons, realizing the low-carbon operation of the coal mine energy system.

[0150] Table 1 Comparison results of system low-carbon performance

[0151]

[0152] It can be seen that the proposed coordinated scheduling method of elastic load and photovoltaic based on the constraints of coal mine production characteristics can improve the matching degree of photovoltaic power generation in the mining area and the source and load of the coal mine, reduce resource and energy waste, and achieve the low-carbon and efficient operation of the coal mine, providing a theoretical basis and data support for the optimal coupling of low-carbon performance between photovoltaic power generation in the mining area and the source and load of the coal mine.

Claims

1. A method for coordinated dispatching of elastic load and photovoltaic based on coal mine production characteristic constraints, characterized in that: The specific steps include: Step 1. Based on the production characteristic constraints of coal mines, an elastic load model is established. The elastic load model includes a strong safety constraint elastic load model and a non-strong safety constraint elastic load model. The strong safety constraint elastic load model includes an elastic load model for mining and transportation, a ventilation elastic load model, and an underground drainage elastic load model. The non-strong safety constraint elastic load model includes an elastic load model for water source heat pumps and an elastic load model for wellhead insulation. Step 2. Based on the elastic load model, determine the known parameters and decision variables and build constraint relationships; ① The upper and lower limits of elastic load power consumption are expressed as follows: 0≤P t ≤P max Where: P t is the electric power of the elastic load at time t, kW; P max is the maximum operating electrical power of the elastic load, kW. ② Elastic load climbing constraint In order to avoid the switching between the stop state and the high-power operation state at adjacent operation moments of the elastic load, the climbing power of the elastic load is limited. The elastic load climbing constraint is expressed as follows: -η p P max ≤P t+1 -P t ≤η p P max Where: η p is the elastic load climbing ratio, %; P t+1 is the electric power of the elastic load at time t+1, kW. ③The power balance constraint of the energy system is expressed as follows: P grid,t +P gen,t =P load,t H buy,t +H gen,t =H load,t Where: P grid,t is the purchased power at time t, kW; P gen,t P is the power generated by the system’s own power generation equipment at time t, kW; load,t is the total power load of all electrical equipment at time t, kW; H buy,t is the purchased heat power at time t, kW; H gen,t is the heating power of the system's own heating equipment at time t, kW; H load,t is the sum of the heat load power of all heat power demands at time t, kW; Step 3. Construct the target function of coordinated dispatching of elastic load and photovoltaic power generation, and calculate and solve it to obtain the power curve of the elastic load's day-ahead operation state, and coordinate the dispatching of elastic load and photovoltaic power generation at different times; The objective function of coordinated dispatching of elastic load and photovoltaic is expressed as follows: Z=β grid P grid +b pv P pv +b gas GAS Where: Z is the total carbon emissions from system operation, tCO2; β grid is the unit carbon emission of the power grid, tCO2 / kWh; β pv is the carbon emission per unit of photovoltaic power generation, tCO2 / kWh; β gas is the unit carbon emission of natural gas, tCO2 / MJ; P grid is the total amount of purchased electricity, kWh; P pv is the total photovoltaic power, kWh; GAS is the total calorific value of natural gas, MJ.

2. The method for coordinated dispatching of elastic load and photovoltaic based on coal mine production characteristic constraints according to claim 1 is characterized in that: In Step 1, the elastic load model of the mining and transportation link includes the elastic load model of the coal mining machine, the elastic load model of the belt conveyor, and the elastic load model of the underground and ground coal bunkers. Specifically: ① The elastic load model of the coal mining machine is expressed as follows: Where: is the operating power of the coal mining machine at time t, kW; is the traction speed of the coal mining machine at time t, m / s; θ is the coefficient related to the structural parameters of the coal mining machine (according to standard ISO5048); is the maximum value of the shearer traction speed, m / s; ②The elastic load model of the belt conveyor is expressed as follows: 0≤v t ≤v max Where: is the average power of the belt conveyor at the tth hour, kW; μ is a coefficient related to the structure of the belt conveyor (according to standard ISO5048); η d , η m are the efficiencies of the motor and drive system, respectively, %; v is the mass per unit length of the belt conveyor in the t period, kg / m; t is the transmission speed of the belt, m / s; W t is the transport volume of the belt conveyor in the tth period, tons / h; v max is the maximum transmission speed of the belt, m / s; The upper limit of the mass that the belt conveyor can bear per unit length, kg / m; ③ The elastic load model of underground and ground coal bunkers is expressed as follows: The upper limit of coal bunker capacity is set at 90% and the lower limit is set at 20%. C t+1 =C t +θ in,t -θ out,t 0.2C N ≤C t ≤0.9C N Where: θ in,t ,θ out,t are the amount of coal transported into and out of the coal bunker at hour t, in tons; C N is the capacity of the coal bunker, tons; C t is the coal storage capacity of the coal bunker at hour t, tons.

3. The method for coordinated dispatching of elastic load and photovoltaic based on coal mine production characteristic constraints according to claim 1 is characterized in that: In Step 1, the ventilation elastic load model includes the air volume calculation model and the fan elastic load model. Specifically: ①The air distribution volume calculation model is expressed as follows: Q P,i =K×(∑Q C,i +∑Q J,i +∑Q D,i +∑Q H,i ) Where: Q P,i is the total air volume, m 3 / h; K is the mine ventilation coefficient, which is 1.2; Q C,i is the air volume required for the coal mining face, m 3 / h;Q J,i is the air volume required for the excavation working face, m 3 / h;Q D,i The air volume required for the independent air supply chamber, m 3 / h;Q H,i is the air volume required for other lanes, m 3 / h; Q C =125k c ×q c Where: 125 is the conversion factor; k c is the gas emission imbalance coefficient of coal mining working face, which is 2.5; q c is the relative gas emission of coal mining face, m 3 / ton; Q J =100k J ×q J Where: 100 is the conversion factor; k J is the gas outburst imbalance coefficient of the excavation working face, which takes the value of 2; q J is the relative gas outflow volume of the excavation working face m 3 / ton; Q D =80N D Where: 80 is the average air volume of a single chamber, m 3 / h; N D is the number of chambers; Q H =133N H Where: 133 is the conversion coefficient of gas outburst in a single tunnel; N H is the number of lanes; ②The fan elastic load model is expressed as follows: P TF,t =f(Q TF,t ,p TF ,η TF ) Q TF,t ≥Q P Where: P TF,t is the operating power of the fan at time t, kW; Q TF,t is the air intake volume of the fan at time t, m 3 / h;p TF is the total wind pressure of the fan, Pa; η TF is the fan operating efficiency, %.

4. The method for coordinated dispatching of elastic load and photovoltaic based on coal mine production characteristic constraints according to claim 1 is characterized in that: In Step 1, the underground drainage elastic load model includes the underground drainage pump elastic load model and the underground water tank elastic load model. Specifically: ①The elastic load model of the underground drainage pump is expressed as follows: P X =f(κ,g,W X ,h X ,or X ) 0≤W X ≤W X，max Where: X is the type of drainage pump; P X is the operating power of X type water pump, kW; κ is the specific gravity of the medium, kg / m 3 ; g is the acceleration due to gravity, which is 9.8N / kg; W X is the operating flow rate of X type water pump, m 3 / h;h X is the head of X type water pump, m; η X is the operating efficiency of X type water pump, %; W X，max is the maximum operating flow rate of X type water pump, m 3 / h; ②The elastic load model of underground water tank is expressed as follows: The empty capacity of the water tank should be maintained at more than 50% of the total capacity, that is: V EM ≥0.5V max Where: V EM is the empty tank capacity of the water tank, m 3 ; V max is the total capacity of the water tank, m 3 .

5. The method for coordinated dispatching of elastic load and photovoltaic based on coal mine production characteristic constraints according to claim 1 is characterized in that: In Step 1, the elastic load model of the water source heat pump is expressed as follows: Where: P hepm,t is the electric power consumed by the water source heat pump unit in period t, kW; H hepm,t is the heating capacity of the water source heat pump unit in time period t, kW; COP is the heating performance coefficient of the water source heat pump unit; H exch,t is the heat absorbed by the water source heat pump unit from the heat source side during the period t, kW; α is the specific heat capacity of the circulating working fluid, J / (kg·℃); ο is the mass flow rate of the circulating working fluid, kg / h; T in 、T out are the inlet and outlet temperatures of the water source heat pump evaporator, ℃ respectively.

6. The method for coordinated dispatching of elastic load and photovoltaic based on coal mine production characteristic constraints according to claim 1 is characterized in that: In Step 1, the wellhead insulation elastic load model is expressed as follows: H FD =f(Q TF,ave ,ρ inair ,C ENT ,T mix ,T low ) H FD,t ≥H FD Where: H FD The basic thermal power required for wellhead antifreeze, kW; Q TF,ave is the average air volume at the wellhead, m 3 / s;ρ inair is the air density, which is 1.28kg / m 3 ; C ENT is the specific heat capacity of air at constant pressure, which is 1.01 kJ / (kg·℃); T mix is the temperature after the cold and hot air are mixed, ℃; T low is the lowest ambient temperature in winter, ℃; H FD,t is the thermal power required for wellhead antifreeze at time t, kW.

7. The method for coordinated dispatching of elastic load and photovoltaic based on coal mine production characteristic constraints according to claim 1, characterized in that: In Step 3, the Gurobi solver is used for calculation and solution.

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