Disclosure of Invention
In order to solve the technical problems, the invention aims to provide a two-stage optimal configuration method of an integrated energy system considering energy reliability, and simultaneously considers the uncertainty of wind power generation and the uncertainty of equipment fault function, so as to effectively improve the utilization of system energy.
The invention discloses a two-stage optimal configuration method of a comprehensive energy system considering energy reliability, which comprises the following steps:
step 1: establishing an electricity-gas combined comprehensive energy system model;
the electric-gas combined integrated energy system model comprises an energy conversion model without considering the energy storage module and an energy conversion model with considering the energy storage module;
the energy storage module comprises: an electrical energy storage device, a cold energy storage device, a hot energy storage device;
the energy conversion comprises: electric energy, cold energy and heat energy converted by the energy conversion equipment; the energy conversion apparatus includes: the system comprises a wind driven generator, an electric refrigerator, an electric boiler, a combined cooling heating and power device and a gas boiler;
the energy conversion model without considering the energy storage module is as follows:
wherein ,P
ELE,tElectric power output by the system for a period t;
the electricity purchasing power and the electricity selling power of the system in the time period t are respectively;
electric power input to the electric refrigerator and the electric boiler respectively in the period of t;
inputting the natural gas power of the combined cooling heating and power generation device for the t time period;
the power generation efficiency of the combined cooling heating and power generation device; p
WT,tThe generated power of the wind driven generator;
wherein ,P
COOL,tCold power output by the system for a period t;
inputting electric power of the electric refrigerator and natural gas power of the combined cooling heating and power device in a time period t;
the refrigeration efficiency of the electric refrigerator and the combined cooling heating and power device is respectively;
wherein ,P
HEAT,tThermal power output by the system in the period t;
inputting the natural gas power of the gas boiler for a time period t;
the heat efficiency of an electric boiler, a combined cooling heating and power device and a gas boiler;
wherein ,
the gas purchasing quantity of the system in the period t; h
LA low calorific value for natural gas combustion;
the energy conversion model considering the energy storage module is as follows:
ΔSm,t=Sm,t-Sm,t-1
Em,t=Pm,tΔt-ΔSm,t
wherein m belongs to { ele, cool, heat }, wherein m represents electricity when ele, cold when cool and heat when heat;
respectively charging and discharging energy power of the energy storage device in the time period of t;
respectively charging and discharging energy to and from the energy storage device in the t time period m; delta S
m,tThe variation of the energy stored in the energy storage device for the t time period m; s
m,t、S
m,t-1M energy stored by the energy storage device m at t and t-1 time periods respectively; p
m,tM power, P output by the system in t period of the energy storage module is not considered
m,t∈{P
ELE,t,P
COOL,t,P
HEAT,t};
Step 2: establishing a two-stage optimization configuration model of the electricity-gas combined comprehensive energy system;
step 2.1: the method aims at the lowest operation and maintenance cost of configuration installation and put into use of energy equipment in engineering, and establishes a two-stage optimization configuration model objective function of the electricity-gas combined comprehensive energy system as follows:
wherein ,CTThe total input cost of the comprehensive energy system; cTIInvestment cost for installing equipment for the system once; cTOThe annual operating cost of the system within the service life; p is a radical ofsProbability of occurrence for a typical day; s is the number of typical days; tau is the coefficient of the equivalent annual investment cost change value, r is the discount rate; y is the age of the system in use;
step 2.2: taking the capacity of system installation equipment as a decision variable optimized in the first stage, and taking the total input cost minimization of the electricity-gas combined comprehensive energy system as an objective function:
f1=min CTI
wherein n belongs to { AC, EB, CCHP, GB, WT }; n denotes an energy conversion device, n is a WT time tableA wind power generator, an electric refrigerator when n is AC, an electric boiler when n is EB, a combined cooling heating and power generation device when n is CCHP, and a gas boiler when n is GB;
the installation states of the kth energy conversion device n and the qth energy storage means m respectively,
1 denotes that the device is installed, 0 denotes that the device is not installed;
the installation cost of the kth energy conversion device n;
the installation cost of the qth m energy storage device;
step 2.3: and (2) optimizing decision variables by taking the operating conditions of energy conversion equipment and an energy storage device of the system as a second stage, and minimizing the typical daily operating cost in the service life of the electricity-gas combined comprehensive energy system as an objective function:
f2=min CTO
CTO=CELE+CGAS+CFO+CTAX
wherein ,CELEThe difference between the electricity purchasing cost and the electricity selling cost of the system; cGASThe gas purchase cost for the system; cFOOperating and maintaining costs for system equipment; cPENPenalizing costs for system load loss;
wherein ,
the prices of the electric energy purchased and sold in the time period t are respectively;
the price of purchasing natural gas for a period of time t;
the operation and maintenance cost for the kth energy conversion device n;
the power of the kth energy conversion device n is input for the period t,
the operating maintenance cost for the qth m energy storage device;
respectively charging and discharging m energy power of the qth m energy storage device in the t time period; c. C
mPenalty cost for load penalty for m energy;
the expected shortage of m energy;
step 2.4: the two-stage optimization configuration model for constructing the electricity-gas combined comprehensive energy system has the following constraint conditions:
wherein ,
maximum values of electric power purchased and sold for the system respectively;
respectively the electricity purchasing state and the electricity selling state of the system in the time period t,
ensuring that the system cannot buy and sell electricity at the same time;
wherein ,
purchasing the maximum value of natural gas power for the system;
wherein ,
for the operation state of the kth energy conversion device n,
1 indicates that the apparatus is in operationState, 0 indicates that the plant is in a shutdown state;
the power of m energy output by the kth energy conversion device n in the t period;
respectively outputting upper and lower limits of m power for the kth energy conversion equipment n in the t period;
wherein ,
respectively charging and discharging energy for the qth m energy storage device in the t time period;
respectively charge and discharge energy to/from the qth m energy storage device,
1, the energy storage device is in a working state, so that the energy storage device can not charge and discharge energy at the same time;
maximum of q m energy storage devices in t periodMinimum charging power;
the maximum and minimum discharge power of the qth m energy storage device in the t time period are respectively;
energy stored by the qth m energy storage device for the t period;
the upper limit and the lower limit of the energy stored by the qth m energy storage device in the t time period are respectively set;
wherein :
m energy reserve power for the kth energy conversion device n during the t period;
reserve power of the qth m energy storage device for the t period;
and step 3: according to Rayleigh distribution of wind speed, obtaining a probability distribution model of power generation and adding the probability distribution model into a constraint condition of a two-stage optimization configuration model;
the power generation capacity probability distribution model is as follows:
wherein :
for wind power generationRated output power of the motor; v. of
r、v
in、v
outRated wind speed and cut-in wind speed and cut-out wind speed respectively;
and 4, step 4: determining the influence of random faults of equipment on a system, establishing two energy reliability indexes and adding the two energy reliability indexes into constraint conditions of a two-stage optimization configuration model;
the two energy reliability indexes are energy shortage rate and energy supplement rate;
the energy shortage rate is as follows:
wherein ,
is the energy shortage rate of m energy,
the installation state of a fault device gamma outputting m energy for a period t;
probability of failure of a device gamma outputting m energy for a period of t;
respectively outputting m-energy power and standby power for the fault equipment gamma in the t period; r
m,tReserve power for energy of m in t period;
the energy supplement rate is as follows:
wherein ,
energy supplement rate of m energy;
the two energy reliability indexes are added into an optimization model to be constrained as follows:
wherein ,
respectively the upper limit of the energy shortage rate and the lower limit of the energy supplement rate.
And 5: and solving the optimal configuration scheme of the electricity-gas combined comprehensive energy system by utilizing a particle swarm algorithm.
Step 5.1: inputting electricity, cold and heat load data and equipment parameters of the comprehensive energy system, setting the number of particles and the number of iterations of the algorithm, and generating an initial population with optimized configuration;
step 5.2: calculating the configuration cost of the system, calling a CPLEX solver to calculate the operation cost of the system, and updating the particle population and the optimal solution;
step 5.3: and when the upper limit of the iteration times is reached or the iteration times is converged, stopping calculating and outputting the optimal solution.
According to the two-stage optimal configuration method of the comprehensive energy system considering the energy reliability, the established two-stage optimal configuration model simultaneously considers the uncertainty of wind power generation and the uncertainty of equipment fault function, the influence of the uncertainty of system energy on the system output can be effectively reduced, the utilization of the system energy is effectively improved, and the system has sustainability and economy.
Detailed Description
The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention and are a part, but not all, of the examples herein.
As shown in fig. 1, a flow chart of a two-stage optimal configuration method of an integrated energy system considering energy reliability according to the present invention is provided, where the method includes the following steps:
step 1: establishing an electricity-gas combined integrated energy system model shown in figure 2;
the electric-gas combined integrated energy system model comprises: the energy conversion model of the energy storage module is not considered, and the energy conversion model of the energy storage module is considered;
the energy storage module comprises: an electrical energy storage device, a cold energy storage device, a hot energy storage device;
the energy conversion comprises: electric energy, cold energy and heat energy converted by the energy conversion equipment; the energy conversion apparatus includes: the system comprises a wind driven generator, an electric refrigerator, an electric boiler, a combined cooling heating and power device and a gas boiler;
the energy conversion model without considering the energy storage module is as follows:
wherein ,P
ELE,tElectric power output by the system for a period t;
the electricity purchasing power and the electricity selling power of the system in the time period t are respectively;
electric power input to the electric refrigerator and the electric boiler respectively in the period of t;
inputting natural gas power of CCHP for a period t;
the power generation efficiency of CCHP; p
WT,tThe generated power of the wind driven generator;
wherein ,P
COOL,tCold power output by the system for a period t;
inputting electric power of the electric refrigerator and natural gas power of CCHP for a period t respectively;
the refrigeration efficiencies of the electric refrigerator and the CCHP respectively;
wherein ,P
HEAT,tThermal power output by the system in the period t;
natural gas fed to the gas boiler for a period of time tPower;
the heat efficiency of an electric boiler, the heat efficiency of a CCHP boiler and the heat efficiency of a gas boiler are respectively set;
wherein ,
the gas purchasing quantity of the system in the period t; h
LA low calorific value for natural gas combustion;
the energy conversion model considering the energy storage module is as follows:
ΔSm,t=Sm,t-Sm,t-1
Em,t=Pm,tΔt-ΔSm,t
wherein m belongs to { ele, cool, heat }, wherein m represents electricity when ele, cold when cool and heat when heat;
respectively charging and discharging energy power of the energy storage device in the time period of t;
respectively charging and discharging energy for the energy storage device in the time period m of t; delta S
m,tThe variation of the energy stored in the energy storage device for the t time period m; s
m,t、S
m,t-1M energy stored by the energy storage device m at t and t-1 time periods respectively; p
m,tM power, P output by the system in t period of the energy storage module is not considered
m,t∈{P
ELE,t,P
COOL,t,P
HEAT,t};
Step 2: establishing a two-stage optimization configuration model of the electricity-gas combined comprehensive energy system;
step 2.1: the method aims at the lowest operation and maintenance cost of configuration installation and put into use of energy equipment in engineering, and establishes a two-stage optimization configuration model objective function of the electricity-gas combined comprehensive energy system as follows:
wherein ,CTThe total input cost of the comprehensive energy system; cTIInvestment cost for installing equipment for the system once; cTOThe annual operating cost of the system within the service life; p is a radical ofsProbability of occurrence for a typical day; s is the number of typical days; tau is the coefficient of the equivalent annual investment cost change value, r is the discount rate; y is the age of the system in use;
step 2.2: taking the capacity of system installation equipment as a decision variable optimized in the first stage, and taking the total input cost minimization of the electricity-gas combined comprehensive energy system as an objective function:
f1=min CTI
wherein n belongs to { AC, EB, CCHP, GB, WT }; n represents an energy conversion device, a wind power generator when n is WT, an electric refrigerator when n is AC, an electric boiler when n is EB, a combined cooling, heating and power generation device when n is CCHP, and a gas boiler when n is GB;
the installation states of the kth energy conversion device n and the qth energy storage means m respectively,
1 denotes that the device is installed, 0 denotes that the device is not installed;
the installation cost of the kth energy conversion device n;
the installation cost of the qth m energy storage device;
step 2.3: and (2) optimizing decision variables by taking the operating conditions of energy conversion equipment and an energy storage device of the system as a second stage, and minimizing the typical daily operating cost in the service life of the electricity-gas combined comprehensive energy system as an objective function:
f2=min CTO
CTO=CELE+CGAS+CFO+CTAX
wherein ,CELEThe difference between the electricity purchasing cost and the electricity selling cost of the system; cGASThe gas purchase cost for the system; cFOOperating and maintaining costs for system equipment; cPENPenalizing costs for system load loss;
wherein ,
are respectively provided withThe price of the electric energy purchased and sold for the time period t;
the price of purchasing natural gas for a period of time t;
the operation and maintenance cost for the kth energy conversion device n;
the power of the kth energy conversion device n is input for the period t,
the operating maintenance cost for the qth m energy storage device;
respectively charging and discharging m energy power of the qth m energy storage device in the t time period; c. C
mPenalty cost for load penalty for m energy;
the expected shortage of m energy;
step 2.4: the two-stage optimization configuration model for constructing the electricity-gas combined comprehensive energy system has the following constraint conditions:
wherein ,
maximum values of electric power purchased and sold for the system respectively;
respectively the electricity purchasing state and the electricity selling state of the system in the time period t,
ensuring that the system cannot buy and sell electricity at the same time;
wherein ,
purchasing the maximum value of natural gas power for the system;
wherein ,
for the operation state of the kth energy conversion device n,
1 represents that the equipment is in a working state, and 0 represents that the equipment is in a shutdown state;
the power of m energy output by the kth energy conversion device n in the t period;
respectively outputting upper and lower limits of m power for the kth energy conversion equipment n in the t period;
wherein ,
respectively charging and discharging energy for the qth m energy storage device in the t time period;
respectively charge and discharge energy to/from the qth m energy storage device,
1, the energy storage device is in a working state, so that the energy storage device can not charge and discharge energy at the same time;
the maximum energy charging power and the minimum energy charging power of the qth m energy storage device in the t time period are respectively;
the maximum and minimum discharge power of the qth m energy storage device in the t time period are respectively;
energy stored by the qth m energy storage device for the t period;
the upper limit and the lower limit of the energy stored by the qth m energy storage device in the t time period are respectively set;
wherein :
m energy reserve power for the kth energy conversion device n during the t period;
reserve power of the qth m energy storage device for the t period;
and step 3: according to Rayleigh distribution of wind speed, obtaining a probability distribution model of power generation and adding the probability distribution model into a constraint condition of a two-stage optimization configuration model;
the power generation capacity probability distribution model is as follows:
wherein :
the rated output power of the wind driven generator; v. of
r、v
in、v
outRated wind speed and cut-in wind speed and cut-out wind speed respectively;
and 4, step 4: determining the influence of random faults of equipment on a system, establishing two energy reliability indexes and adding the two energy reliability indexes into constraint conditions of a two-stage optimization configuration model;
the two energy reliability indexes are energy shortage rate and energy supplement rate;
the energy shortage rate is as follows:
wherein ,
is the energy shortage rate of m energy,
the installation state of a fault device gamma outputting m energy for a period t;
probability of failure of a device gamma outputting m energy for a period of t;
respectively outputting m-energy power and standby power for the fault equipment gamma in the t period; r
m,tReserve power for energy of m in t period;
the energy supplement rate is as follows:
wherein ,
energy supplement rate of m energy;
the two energy reliability indexes are added into an optimization model to be constrained as follows:
wherein ,
respectively the upper limit of the energy shortage rate and the lower limit of the energy supplement rate.
And 5: the optimal configuration scheme of the electricity-gas combined integrated energy system is solved by utilizing a particle swarm algorithm, and the specific solving flow is shown in figure 3. The method comprises the following steps:
step 5.1: inputting electricity, cold and heat load data and equipment parameters of the comprehensive energy system, setting the number of particles and the number of iterations of the algorithm, and generating an initial population with optimized configuration;
step 5.2: calculating the configuration cost of the system, calling a CPLEX solver to calculate the operation cost of the system, and updating the particle population and the optimal solution;
step 5.3: and when the upper limit of the iteration times is reached or the iteration times is converged, stopping calculating and outputting the optimal solution.
FIG. 4 is a typical seasonal wind power output versus load curve for the combined electric and gas energy system of FIG. 2.
Taking a certain area in the north as an example, explaining the two-stage optimization configuration method of the comprehensive energy system considering energy reliability, which is provided by the invention, according to the steps 1-4, a two-stage optimization configuration model of the electricity-gas combined comprehensive energy system is constructed, electricity is purchased by adopting time-of-use electricity price, the peak time period is 8: 00-14: 00, 19: 00-22: 00, the price is 1.2 yuan/kW.h, the average time period is 14: 00-19: 00, the price is 0.8 yuan/kW.h, the valley time period is 22: 00-8: 00, and the price is 0.4 yuan/kW.h; the price of electricity sold is 0.64 yuan/kW.h; the price of purchasing natural gas is 2.93 yuan/m3. The penalty cost of the loss of the electric energy, the cold energy and the heat energy is 8.05, 3.04 and 3.59 yuan/kW.h respectively. The service life of the comprehensive energy system constructed by the method is 20 years, the discount rate is 1 percent, and each energy deviceThe installation and operating costs associated with the energy storage device are shown in appendix table 1. The probability of occurrence in spring and autumn, winter and summer on typical days is 0.4, 0.4 and 0.2 respectively.
TABLE 1 capital cost of equipment and operating parameters
And (3) respectively considering and not considering the energy storage module according to the step 1, respectively introducing the reliability index in the step 4 into or not introducing the constraint, and setting a scene as shown in a table 2.
TABLE 2 scene settings
According to the step 5, the algorithm shown in fig. 3 is adopted, and the solution optimization results are shown in tables 3 and 4.
Table 3 equipment configuration number and capacity results in each scene
TABLE 4 optimization results under various scenarios
As can be seen from tables 3 and 4, compared with scene 1, scene 2 considers two reliability indexes, the number of installed electric boilers, electric refrigerators and energy storage modules is increased, and the number of combined cooling, heating and power generation devices, gas boilers and wind power generators is reduced, compared with the configuration scheme of scene 1, scene 2 reduces the investment cost of 2490 ten thousand yuan, the annual operation cost is slightly higher than that of scene 1 by 22.13 ten thousand yuan, but the shortage of electric, cold and heat energy is greatly reduced and is about one tenth of scene 1, the annual penalty cost of 35.59 ten thousand yuan is reduced, the annual penalty cost accounts for 91.23% of the annual penalty cost of scene 1, and the optimization result is that compared with the configuration scheme of scene 2, scene 1, the total investment cost of the system is reduced by 2732.89 ten thousand yuan; compared with the scenario 3, the scenario 4 considers two reliability indexes, the number of the installed electric refrigerators, the gas boilers and the energy storage devices is increased, the number of the electric boilers and the wind power generators is reduced, the investment cost of the scenario 4 is increased by 630 ten thousand compared with the configuration scheme of the scenario 3, the annual operation cost is reduced by 161.05 ten thousand, the shortage of electricity, cold and heat energy is effectively reduced, the annual penalty cost of 37.9 ten thousand yuan is reduced, the annual penalty cost accounts for 86.74% of the annual penalty cost of the scenario 3, and the configuration of the scenario 4 and the operation scheme have the optimization result that the total investment cost of the system is reduced by 2960.16 thousand yuan compared with the scenario 3. Therefore, after the reliability index is added into the optimized model constraint, the shortage energy of the system can be effectively reduced, the system is more stable and reliable, the total input cost of the system can be reduced, and the stability and the economical efficiency of the system are ensured.
The technical solutions and the accompanying drawings provided in the embodiments of the present invention are used for further illustrating the present invention and are not limited thereto, and it should be noted that a person skilled in the art should know that the technical solutions described in the foregoing embodiments can be modified or some or all of the technical features can be equivalently replaced, and these modifications or replacements do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the present invention.