CN110245863B - An electric combined system and online regulation method based on electric conversion energy storage - Google Patents

Abstract

The invention provides an electric combined system based on electric conversion and energy storage and an online regulation and control method, and relates to the technical field of electric combined systems. The method comprises the following steps: acquiring energy source information of a current time period t, air pressure of an air storage tank and load information of the current time period t in the electric combined system; monitoring the output of the wind turbine generator at the current time t in the electric combined system and the variation of the electric load and the heat load at the current time t in the load unit, judging whether the electric combined system generates energy updating, if so, adopting an online regulation and control strategy of electric conversion energy storage, and if not, maintaining the original operation state; if T is less than T, the scheduling time period is ended, and the energy source information, the air pressure of the air storage tank and the load information are acquired again after T = T + 1; if T = T, the scheduling of this cycle is ended. Through the orderly cooperation among the electric gas conversion equipment, the gas turbine, the gas cogeneration unit, the gas boiler and the gas storage tank, the flexibility of the operation of the electric combined system is enhanced.

Description

An electrical combined system and online regulation method based on electrical conversion energy storage

technical field

The invention relates to the technical field of electrical combined systems, in particular to an electrical combined system based on electrical conversion and energy storage and an online regulation method.

Background technique

my country is now the world's largest wind power market. As of 2016, my country's wind power generation capacity accounted for 35% of the global wind power generation capacity. Despite the increasing penetration of wind power, my country still faces serious wind curtailment problems, especially in the northern provinces. The main obstacle to wind power accommodation is the lack of flexibility of the power system. However, in northern China, more than 60% of generating units are combined heat and power (CHP) units. In order to ensure the heating demand, CHP units adopt the operation mode of "power determined by heat". The operation mode of cogeneration units that "constantly determines power by heat" reduces the space for wind power to be connected to the grid and intensifies the phenomenon of wind curtailment.

As the use of new energy has attracted widespread attention, the installed capacity of wind power and other new energy power generation systems has continued to increase. It is estimated that the installed capacity of wind turbines will reach 200 million kilowatts by 2020. However, due to the asynchronous construction of wind farms and power grids, and the mismatch between wind power characteristics and peak-shaving capabilities of the power grid, wind curtailment has occurred in some areas, resulting in energy waste and economic losses. Integrated energy system architecture Integrating renewable energy is one of the important means to improve the utilization rate of renewable energy. The microgrid system based on natural gas and electric power supply is a typical user-side comprehensive energy system form. By coordinating and optimizing the natural gas and electric power links in the microgrid, the utilization rate of renewable energy can be improved; in addition, the storage system can also be developed in the coupling system. Gas, electricity storage, and potential storage technologies will improve the utilization rate of renewable energy, and finally form multiple consumption technologies and multiple energy storage technologies to reduce wind curtailment. Due to the high cost of large-scale storage of electricity, and the relatively low cost of gas storage, gas storage technology can be vigorously developed in microgrids. For example, through the power-to-gas technology, excess wind power is converted into natural gas for storage, reducing the phenomenon of abandoning wind and light.

The power-to-gas technology is to convert the rich electric energy into natural gas or hydrogen during the low load and peak hours of renewable energy output, and store it in the natural gas pipeline network or natural gas storage equipment; during the power shortage period, the stored gas is converted into electric energy or heat energy Provided to users, thereby improving the ability of the microgrid to absorb renewable energy during low load periods. The power-to-gas technology also increases the coupling effect of the electricity-gas joint link, and enhances the functional stability between the power network and the natural gas network system.

Power-to-gas converts electrical energy into chemical energy, which is stored in hydrogen or natural gas. According to the different final products of power-to-gas, power-to-gas technology can be divided into two stages: electrolysis of hydrogen and methanation. First of all, excess electric energy is used to electrolyze water to produce hydrogen, and its energy is used to produce hydrogen by electrolyzing water, which can be directly used in industrial production or gas-fired power generation under safety constraints. The chemical equation is:

2H ₂ O→2H ₂ +O ₂ (1)

The hydrogen produced by electrolysis can be used directly, but due to the difficulty of hydrogen storage and transportation, it is generally in the form of electrolysis of natural gas, that is, methanation. Natural gas has a higher unit energy density than hydrogen, and can be directly injected into existing natural gas networks for large-scale storage and long-distance transmission. Electric-to-natural gas is based on the electrolysis of hydrogen, using carbon dioxide and hydrogen to react under high temperature and high pressure to generate methane. The chemical equation is:

CO ₂ +4H ₂ →CH ₄ +2H ₂ O (2)

The methanation process is an exothermic catalytic reaction, and the carbon dioxide required for the reaction can come from the waste gas generated in the industrial production process, fossil fuel combustion power generation, biomass and air, etc. Methanated natural gas can be injected into the natural gas network for storage, and natural gas is generally stored in abandoned oil and gas fields, aquifers or salt caverns. The storage capacity of natural gas is huge, up to hundreds of trillion cubic meters, which is equivalent to storing electric energy reaching the level of TW·h. During the peak hours of electric load, natural gas is converted into electric energy through fuel cells or gas turbines to form an electric-gas-electric cycle energy storage system. The traditional energy storage equipment power-to-gas storage capacity is small and the discharge time is short, which cannot effectively consume large-scale wind power, and it is impossible to achieve long-term and large-scale time-space translation of energy; traditional energy storage equipment is optimized for a single-time section, resulting in a lack of flexibility in regulation;

Contents of the invention

The technical problem to be solved by the present invention is to provide an electrical combined system based on electrical conversion and energy storage and an online control method for the deficiencies of the above-mentioned prior art. The orderly cooperation between the gas tanks enhances the flexibility of the electrical combined system operation.

In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is:

On the one hand, the present invention provides an electrical combination system based on electrical conversion and energy storage, including an energy source information acquisition unit, an energy conversion unit and a load unit;

The load unit includes an electric load unit and a heat load unit, the electric load unit is used to provide electric load for the electric equipment of the load, and the heat load unit is used to provide heat energy for the user of the load;

The energy source information acquisition unit includes an energy information collector and a natural gas busbar; the energy information collector is connected to the wind turbine, the power grid, and the energy conversion unit respectively, and the natural gas busbar is connected to the natural gas network;

The energy conversion unit includes: power-to-gas equipment, a gas turbine, a gas-fired cogeneration unit, a gas boiler, and a gas storage tank; the input end of the power-to-gas equipment is connected to an electric bus, and the electric bus is connected to an electric load unit; The output end of the power-to-gas equipment is connected to the input end of the gas storage tank; the output end of the gas storage tank is connected to the input end of the gas turbine; the output end of the gas turbine is connected to the electric bus; the energy information collector is respectively It is connected with the gas cogeneration unit and the gas boiler; the input end of the gas boiler is connected with the natural gas bus; the output end of the gas boiler is connected with the heat load unit; the input end of the gas cogeneration unit is connected with the natural gas The busbar is connected; the output end of the gas cogeneration unit is respectively connected with the input end of the heat load unit and the electric busbar;

On the other hand, the present invention provides an online regulation method based on electrical conversion energy storage, which is realized by the electrical combination system based on electrical conversion energy storage, including the following steps:

Step 1: Take 1 hour as a scheduling period and 24 scheduling periods as a scheduling period T to obtain the energy source information of the current period t obtained by the energy information collector of the electrical joint system, and the air pressure P _S of the gas storage tank in the energy conversion unit and the load information of the current period t in the load unit; the energy source information includes the gas consumption power P _gas,CHP of the gas-fired cogeneration unit and the gas consumption power P _gas,GB of the gas-fired boiler, the wind turbine output P _F , Online shopping power P _grid ; the load information includes electric load P _E and thermal load P _H ;

Step 2: Monitor the wind turbine output P _F of the current period t in the energy source information collector in the electrical combined system and the changes in the electric load _{PE and thermal load P H of} the load unit in the current period t, and judge the electric combined system Whether energy update occurs, if yes, go to step 3, if not, keep the original running state and go to step 1;

Among them, the situations that trigger energy update include:

1) The variation of wind turbine output exceeds the threshold εP _F(t-1) : |P _F -P _F(t-1) |>εP _F(t-1) ;

2) The change in energy demand of the load unit exceeds the threshold τL _(t-1) : |LL _(t-1) |>τL _(t-1) ;

In the formula, L=P _E + _PH , ε, τ are parameters, and their values are the upper and lower control ranges generated according to the actual load situation; t-1 represents the previous period, and t represents the current period;

Step 3: When the energy update occurs in the electric combined system, adopt the online control strategy of electric conversion energy storage. The control strategy is to maintain the status quo when the supply of gas-fired cogeneration units can meet the system demand, and the supply of gas-fired cogeneration units cannot When the system demand is met, the gas-fired cogeneration unit is preferred to meet the demand of the heat load. The gas boiler is used as a backup heat source, and the power is redistributed according to the principle of user priority; then judge whether the electric load meets the system demand; The power-to-gas device is used to convert excess wind power output into natural gas, and the natural gas is stored in the gas storage tank; if it is not satisfied, the gas storage tank of the power-to-gas device is released, and the gas turbine is used to convert natural gas into electric energy to supply the system's electric load or Purchase electricity P grid from the _grid ;

Step 4: Judging whether the current period t of the electrical combined system is less than the scheduling period T, if t<T, then the scheduling period ends, and after setting t=t+1, execute step 1; if t=T, then end the scheduling of this period .

Described step 3 comprises the steps:

Step 3.1: Prioritize the use of gas-fired cogeneration units to meet the demand for heat load, and gas-fired boilers as backup heat sources;

Judging whether the heat load P _H in the electric combined system is supplied by the gas-fired cogeneration unit meets the system demand, and the sign to determine whether the heat load demand is met is:

In the formula, when W _L =1, it means that the heat load demand is met, and when W _L =0, it means that the heat load demand is not met; P _CHP,h is the heat production power of the gas-fired cogeneration unit; where, the output of the gas-fired cogeneration unit The thermal power is:

P _CHP,h ＝η _CHP,h P _gas,CHP

In the formula, _ηCHP,h represents the heat conversion efficiency of the gas-fired cogeneration unit; _Pgas,CHP represents the gas consumption power of the gas-fired cogeneration unit;

If W _L = 1, that is, the supply of the gas-fired cogeneration unit can meet the system demand, the boiler will not start to work, and the current working state will be maintained;

If W _L = 0, that is, the supply of the gas cogeneration unit cannot meet the system demand, the gas boiler is started as the hot standby of the gas cogeneration unit, and works jointly with the gas cogeneration unit to meet the heat load demand:

P _CHP,h +P _GB,h ≥ P _H ;

Among them, the heat production power of the gas boiler:

P _GB,h ＝η _GB P _gas,GB

In the formula, P _GB,h is the heat production power of the gas boiler; η _GB represents the efficiency of the gas boiler; P _{gas, GB} represents the gas consumption power of the gas boiler;

Step 3.2: According to the output P _F of the wind turbine unit, the electrical output P _CHP of the gas cogeneration unit and the electrical load P _E in the current period, determine whether the electrical load meets the system demand in the period t; the sign that the system meets the electrical load demand:

In the formula, when U _t =1, it means excess electric energy, and when U _t =0, it means insufficient electric energy;

Among them, the generating power of the gas cogeneration unit is:

P _CHP ＝η _CHP P _gas,CHP

In the formula, _ηCHP represents the electrical conversion efficiency of the gas-fired cogeneration unit.

If U _t = 1, that is, the electric load can meet the system demand during the t period, and the electric energy is surplus, proceed to step 3.3; if U _t = 0, that is, the electric load cannot meet the system demand during the t period, then jump to step 3.4;

Step 3.3: If the power generation is too large and there is still a surplus after meeting the basic electric load, the system uses a power-to-gas device to convert the excess wind power output into natural gas, and stores the natural gas in a gas storage tank to judge the gas storage of the power-to-gas equipment Whether the tank storage capacity meets the gas storage conditions:

In the formula, when V _t = 1, it means that gas storage is possible, and when V _t = 0, it means that gas storage is not possible; S _s is the storage capacity of the power-to-gas gas storage tank in the current scheduling period, and S _s,min is the power-to-gas gas storage tank The minimum storage capacity inside, S _s,max is the maximum storage capacity inside the power-to-gas storage tank.

The storage capacity of the gas storage tank of the power-to-gas equipment is:

△P＝P _S -P ₀

In the formula, K is the gas consumption per unit time of the compressor in the gas storage tank; _{P a} is the atmospheric pressure at the altitude where the power-to-gas gas storage tank is installed; The variation of P ₀ ; K _L is the comprehensive parameter of the internal pressure of the power-to-air gas storage tank during the current scheduling period; Q is the output gas flow rate of the power-to-gas gas storage tank during the current scheduling period;

When V _t = 0, that is, the storage capacity of the gas storage tank of the power-to-gas equipment does not meet the gas storage conditions, then jump to step 4; if V _t = 1, it means that the capacity of the gas storage tank of the power-to-gas equipment meets the gas storage conditions, then set The excess natural gas converted from wind power is stored in the gas storage tank, and then skip to step 3.5;

Among them, the electric energy consumed by the power-to-gas equipment is:

In the formula, P _P2G represents the power consumption of the power-to-gas equipment; H _g represents the calorific value of natural gas; η _P2G represents the conversion efficiency of the power-to-gas equipment;

Step 3.4: If the electric load cannot meet the basic electric load demand of the system during the period t, judge whether the storage capacity of the gas storage tank of the power-to-gas device meets the gas release condition; Supply system electric load for electric energy, and then jump to step 3.5; if not, purchase electricity P grid from the _grid ;

Described deflation condition is:

In the formula, when X _t = 1, it means deflation is possible, and when X _t = 0, it means that deflation is not possible;

Among them, when the gas storage tank cannot release gas, it purchases electricity from the grid:

P _grid ＝P _E -P _CHP -P _F

In the formula, P _grid represents the electricity purchased from the grid when the gas storage tank cannot be released;

Gas turbine power generation:

P _GT ＝η _GT QH _g

In the formula, _PGT represents the generating power of the gas turbine; _ηGT represents the conversion efficiency of the gas turbine;

Step 3.5: Judging whether the current time period t has reached the power balance state:

In the formula, if Y _t = 1, the state of electric energy balance is reached, then jump to step 4; if Y _t = 0, that is, the state of electric energy balance cannot be reached, then purchase power P _grid from the grid until the state of electric energy balance is returned Step 4;

Among them, when the electric energy is in a balanced state, the electricity purchased from the grid:

P _grid ＝P _E -P _CHP -P _F -P _GT

In the formula, P _grid represents the power purchased from the grid when the power balance is reached.

The beneficial effects produced by adopting the above technical solution are: the present invention provides an electric combined system based on electrical conversion energy storage and an online regulation method. This system performs unitized processing on the electric-pneumatic combined system, making it easy to control and execute On-line regulation strategy, in order to stabilize the fluctuation of wind power output and load demand, the present invention proposes an on-line regulation strategy. This strategy uses power-to-gas equipment to improve the wind power consumption capacity of the electricity-gas interconnected integrated energy system, and at the same time, in the low power load and wind power The load fluctuation can be effectively slowed down during the peak output period; the two-way energy flow between the power network and the natural gas network is realized through the power-to-gas equipment and the gas turbine, the coupling of the power-gas network is enhanced, the energy utilization efficiency is improved, and the stability of the system is improved. The energy is distributed through the online regulation strategy of electricity-gas conversion energy storage, so that the system has a good and flexible regulation function. Compared with traditional energy storage equipment, this method has larger power-to-gas storage capacity and longer discharge time, which can effectively accommodate large-scale wind power and realize long-term and large-scale time-space translation of energy; the gas turbine unit and power-to-gas technology have realized power network and natural gas Two-way energy flow between networks enhances the coupling of electric-gas networks, improves energy utilization efficiency and improves system stability;

Description of drawings

Fig. 1 is the structural diagram of the electrical combination system of electrical conversion energy storage provided by the embodiment of the present invention;

Fig. 2 is a flowchart of an online regulation method for electrical conversion energy storage provided by an embodiment of the present invention;

detailed description

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

The method of this example is as follows.

On the one hand, the present invention provides an electrical combined system based on electrical conversion and energy storage, as shown in Figure 1, including an energy source information collection unit, an energy conversion unit and a load unit;

The load unit includes an electric load unit and a heat load unit, the electric load unit is used to provide electric load for the electric equipment of the load, and the heat load unit is used to provide heat energy for the user of the load;

The energy source information collection unit is used to collect the output information of the wind turbine, the information on the power grid and the natural gas bus; it includes an energy information collector and a natural gas bus; the energy information collector is connected to the wind turbine, the power grid and the energy conversion unit respectively, The natural gas bus is connected to the natural gas network;

The energy conversion unit includes: power-to-gas equipment (P2G), gas turbine, gas-fired combined heat and power unit (CHP), gas boiler and gas storage tank; the input end of the power-to-gas equipment is connected to the electric bus, and the electric bus is connected to the electric bus. The load unit is connected; the output end of the power-to-gas equipment is connected to the input end of the gas storage tank; the output end of the gas storage tank is connected to the input end of the gas turbine; the output end of the gas turbine is connected to the electric bus The energy information collector is connected to the gas cogeneration unit and the gas boiler respectively; the input end of the gas boiler is connected to the natural gas busbar; the output end of the gas boiler is connected to the heat load unit; the gas cogeneration The input end of the unit is connected to the natural gas busbar; the output end of the gas cogeneration unit is respectively connected to the input end of the heat load unit and the electric busbar;

The energy conversion unit, as the energy hub of the electric combined system, takes into account two coupling forms of power-to-gas equipment and gas turbines. The operating state of the gas storage tank is determined by monitoring the air pressure P _S of the gas storage tank in the current period. Power-to-gas converts excess wind power into natural gas and injects it into gas storage tanks for storage. On the contrary, the gas turbine consumes the natural gas in the gas storage tank and gathers the obtained electric energy to the electric bus, realizing the two-way energy flow between the electric power network and the natural gas network.

On the other hand, the present invention provides an on-line control method based on electricity-gas conversion energy storage, which is realized through the electrical combined system based on electrical conversion energy storage, as shown in Figure 2, including the following steps:

Step 1: Taking 1 hour as a scheduling period and 24 scheduling periods as a scheduling period T, obtain the energy source information of the current period t in the energy source information collector of the electric-gas combined system, and the air pressure of the gas storage tank in the energy conversion unit P _S and the load information of the current period t in the load unit; the energy source information includes the gas consumption power P _gas,CHP of the gas-fired cogeneration unit and the gas consumption power P _gas,GB of the gas boiler, the output power P _F of the wind turbine, Purchase electricity from the grid P _grid ; the load information includes electric load P _E and thermal load P _H ;

Step 2: Monitor the output PF of the wind turbine in the current period t in the energy source information collector of the electricity-gas combined system and the changes in the electric load _{PE and thermal load P H in the} load unit in the current period t, and judge the power –Whether energy update occurs in the combined gas system, if yes, go to step 3, if not, keep the original running state and go to step 1;

Among them, the situations that trigger energy update include:

1) The variation of wind turbine output exceeds a certain threshold: |P _F -P _F(t-1) |>εP _F(t-1) ;

2) The change in energy demand of the load unit exceeds a certain threshold: |LL _(t-1) |>τL _(t-1) ;

In the formula, L=P _E +P _H , ε, τ are parameters, and the values of ε, τ are the upper and lower control ranges generated according to the actual load situation; t-1 represents the previous period, t represents the current period; L _{( t-1)} = P _E (t-1) + P _H (t-1);

Step 3: When the energy update occurs in the electricity-gas combined system, an online regulation strategy based on electricity-gas conversion energy storage is adopted. The regulation strategy is to maintain the status quo when the supply of gas cogeneration units can meet the system demand, When the supply of gas-fired cogeneration units cannot meet the system demand, the gas-fired cogeneration unit is preferred to meet the demand of heat load, and the gas boiler is used as a backup heat source, and the power is redistributed according to the principle of user priority; then judge whether the electric load meets the system demand; if If it is satisfied and the electric energy is surplus, the system adopts the power-to-gas device to convert the excess wind power output into natural gas, and stores the natural gas in the gas storage tank; To supply the electric load of the system with electric energy or to purchase electricity P _grid from the grid; the specific steps are as follows:

Step 3.1: Since the fixed part of the thermal load and electrical load is not adjustable, the gas-fired cogeneration unit is preferred to meet the demand of the thermal load, and the gas-fired boiler is used as a backup heat source;

Judging whether the heat load P _H in the electricity-gas combined system is supplied by the gas-fired cogeneration unit meets the system demand, and the sign to determine whether the heat load demand is met is:

In the formula, when W _L =1, it means that the heat load demand is met, and when W _L =0, it means that the heat load demand is not met; P _CHP,h is the heat production power of the gas-fired cogeneration unit; where, the output of the gas-fired cogeneration unit The thermal power is:

P _CHP,h ＝η _CHP,h P _gas,CHP

In the formula, _ηCHP,h represents the heat conversion efficiency of the gas-fired cogeneration unit; _Pgas,CHP represents the gas consumption power of the gas-fired cogeneration unit;

If W _L = 1, that is, the supply of the gas-fired cogeneration unit can meet the system demand, the boiler will not start to work, and the current working state will be maintained;

If W _L = 0, that is, the supply of the gas cogeneration unit cannot meet the system demand, the gas boiler is started as the hot standby of the gas cogeneration unit, and works jointly with the gas cogeneration unit to meet the heat load demand:

P _CHP,h +P _GB,h ≥ P _H ;

Among them, the heat production power of the gas boiler:

P _GB,h ＝η _GB P _gas,GB

In the formula, P _GB,h is the heat production power of the gas boiler; η _GB represents the efficiency of the gas boiler; P _{gas, GB} represents the gas consumption power of the gas boiler;

Step 3.2: According to the output P _F of the wind turbine unit, the electrical output P _CHP of the gas cogeneration unit and the electrical load P _E in the current period, determine whether the electrical load meets the system demand in the period t; the sign that the system meets the electrical load demand:

In the formula, when U _t =1, it means excess electric energy, and when U _t =0, it means insufficient electric energy;

Among them, the generating power of the gas cogeneration unit is:

P _CHP ＝η _CHP P _gas,CHP

In the formula, _ηCHP represents the electrical conversion efficiency of the gas-fired cogeneration unit.

If U _t = 1, that is, the electric load can meet the system demand during the t period, and the electric energy is surplus, proceed to step 3.3; if U _t = 0, that is, the electric load cannot meet the system demand during the t period, then jump to step 3.4;

Step 3.3: If the power generation is too large and there is still a surplus after meeting the basic electric load, the system uses a power-to-gas device to convert the excess wind power output into natural gas, and stores the natural gas in a gas storage tank to judge the gas storage of the power-to-gas equipment Whether the tank storage capacity meets the gas storage conditions:

In the formula, when V _t = 1, it means that gas storage is possible, and when V _t = 0, it means that gas storage is not possible; S _s is the storage capacity of the power-to-gas gas storage tank in the current scheduling period, and S _s,min is the power-to-gas gas storage tank The minimum storage capacity inside, S _s,max is the maximum storage capacity inside the power-to-gas storage tank.

The storage capacity of the gas storage tank of the power-to-gas equipment is:

△P＝P _S -P ₀

In the formula, K is the gas consumption per unit time of the compressor in the gas storage tank; _{P a} is the atmospheric pressure at the altitude where the power-to-gas gas storage tank is installed; The variation of P ₀ ; K _L is the comprehensive parameter of the internal pressure of the power-to-air gas storage tank during the current scheduling period; Q is the output gas flow rate of the power-to-gas gas storage tank during the current scheduling period;

When V _t = 0, that is, the storage capacity of the gas storage tank of the power-to-gas equipment does not meet the gas storage conditions, then jump to step 4; if V _t = 1, it means that the capacity of the gas storage tank of the power-to-gas equipment meets the gas storage conditions, then set The excess natural gas converted from wind power is stored in the gas storage tank, and then skip to step 3.5;

Among them, the electric energy consumed by the power-to-gas equipment is:

In the formula, P _P2G represents the power consumption of the power-to-gas equipment; H _g represents the calorific value of natural gas; η _P2G represents the conversion efficiency of the power-to-gas equipment;

Step 3.4: If the electric load cannot meet the basic electric load demand of the system during the period t, judge whether the storage capacity of the gas storage tank of the power-to-gas device meets the gas release condition; Supply system electric load for electric energy, and then jump to step 3.5; if not, purchase electricity P grid from the _grid ;

Described deflation condition is:

In the formula, when X _t = 1, it means deflation is possible, and when X _t = 0, it means that deflation is not possible;

Among them, when the gas storage tank cannot release gas, it purchases electricity from the grid:

P _grid ＝P _E -P _CHP -P _F

In the formula, P _grid represents the electricity purchased from the grid when the gas storage tank cannot be released;

Gas turbine power generation:

P _GT ＝η _GT QH _g

In the formula, _PGT represents the generating power of the gas turbine; _ηGT represents the conversion efficiency of the gas turbine;

Step 3.5: Judging whether the current time period t has reached the power balance state:

In the formula, if Y _t = 1, the state of electric energy balance is reached, then jump to step 4; if Y _t = 0, that is, the state of electric energy balance cannot be reached, then purchase power P _grid from the grid until the state of electric energy balance is returned Step 4;

Among them, when the electric energy is in a balanced state, the electricity purchased from the grid:

P _grid ＝P _E -P _CHP -P _F -P _GT

In the formula, P _grid represents the power purchased from the grid when the power balance is reached.

Step 4: Judging whether the current period t of the electricity-gas combined system is less than the scheduling period T, if t<T, then the scheduling period ends, after setting t=t+1, execute step 1; if t=T, then end this period scheduling.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some or all of the technical features; these modifications or replacements do not make the essence of the corresponding technical solutions depart from the scope defined by the claims of the present invention.

Claims (3)

1. An electrical combination system based on electrical conversion and energy storage, characterized in that: it includes an energy source information acquisition unit, an energy conversion unit and a load unit; The load unit includes an electric load unit and a heat load unit, the electric load unit is used to provide electric load for the electric equipment of the load, and the heat load unit is used to provide heat energy for the user of the load; The energy source information acquisition unit includes an energy information collector and a natural gas busbar; the energy information collector is connected to the wind turbine, the power grid, and the energy conversion unit respectively, and the natural gas busbar is connected to the natural gas network; The energy conversion unit includes: power-to-gas equipment, a gas turbine, a gas cogeneration unit, a gas boiler, and a gas storage tank; the input end of the power-to-gas equipment is connected to an electric bus, and the electric bus is connected to an electric load unit; The output end of the power-to-gas equipment is connected to the input end of the gas storage tank; the output end of the gas storage tank is connected to the input end of the gas turbine; the output end of the gas turbine is connected to the electric bus; the energy information collector is respectively It is connected with the gas cogeneration unit and the gas boiler; the input end of the gas boiler is connected with the natural gas bus; the output end of the gas boiler is connected with the heat load unit; the input end of the gas cogeneration unit is connected with the natural gas The busbars are connected; the output ends of the gas cogeneration unit are respectively connected with the input ends of the heat load unit and the electric busbars. 2. An on-line control method based on electrical conversion energy storage, realized by an electrical combination system based on electrical conversion energy storage according to claim 1, characterized in that: comprising the following steps: Step 1: Take 1 hour as a scheduling period and 24 scheduling periods as a scheduling period T to obtain the energy source information of the current period t obtained by the energy information collector of the electrical joint system, and the air pressure P _S of the gas storage tank in the energy conversion unit and the load information of the current period t in the load unit; the energy source information includes the gas consumption power P _gas,CHP of the gas-fired cogeneration unit and the gas consumption power P _gas,GB of the gas-fired boiler, the wind turbine output P _F , Online shopping power P _grid ; the load information includes electric load P _E and thermal load P _H ; Step 2: Monitor the wind turbine output P _F of the current period t in the energy source information collector in the electrical combined system and the changes in the electric load _{PE and thermal load P H of} the load unit in the current period t, and judge the electric combined system Whether energy update occurs, if yes, go to step 3, if not, keep the original running state and go to step 1; Among them, the situations that trigger energy update include: 1) The variation of wind turbine output exceeds the threshold εP _F(t-1) : |P _F -P _F(t-1) |>εP _F(t-1) ; 2) The change in energy demand of the load unit exceeds the threshold τL _(t-1) : |LL _(t-1) |>τL _(t-1) ; In the formula, L=P _E + _PH , ε, τ are parameters, and their values are the upper and lower control ranges generated according to the actual load situation; t-1 represents the previous period, and t represents the current period; Step 3: When the energy update occurs in the electric combined system, adopt the online control strategy of electric conversion energy storage. The control strategy is to maintain the status quo when the supply of gas-fired cogeneration units can meet the system demand, and the supply of gas-fired cogeneration units cannot When the system demand is met, the gas-fired cogeneration unit is preferred to meet the demand of the heat load. The gas boiler is used as a backup heat source, and the power is redistributed according to the principle of user priority; then judge whether the electric load meets the system demand; The power-to-gas device is used to convert excess wind power output into natural gas, and the natural gas is stored in the gas storage tank; if it is not satisfied, the gas storage tank of the power-to-gas device is released, and the gas turbine is used to convert natural gas into electric energy to supply the system's electric load or Purchase electricity P grid from the _grid ; Step 4: Judging whether the current period t of the electrical combined system is less than the scheduling period T, if t<T, then the scheduling period ends, and after setting t=t+1, execute step 1; if t=T, then end the scheduling of this period . 3. An online control method based on electrical conversion energy storage according to claim 2, characterized in that: said step 3 comprises the following steps: Step 3.1: Prioritize the use of gas-fired cogeneration units to meet the demand for heat load, and gas-fired boilers as backup heat sources; Judging whether the heat load P _H in the electric combined system is supplied by the gas-fired cogeneration unit meets the system demand, and the sign to determine whether the heat load demand is met is:

In the formula, when W _L =1, it means that the heat load demand is met, and when W _L =0, it means that the heat load demand is not met; P _CHP,h is the heat production power of the gas-fired cogeneration unit; where, the output of the gas-fired cogeneration unit The thermal power is: P _CHP,h ＝η _CHP,h P _gas,CHP In the formula, _ηCHP,h represents the heat conversion efficiency of the gas-fired cogeneration unit; _Pgas,CHP represents the gas consumption power of the gas-fired cogeneration unit; If W _L = 1, that is, the supply of the gas-fired cogeneration unit can meet the system demand, the boiler will not start to work, and the current working state will be maintained; If W _L = 0, that is, the supply of the gas cogeneration unit cannot meet the system demand, the gas boiler is started as the hot standby of the gas cogeneration unit, and works jointly with the gas cogeneration unit to meet the heat load demand: P _CHP,h +P _GB,h ≥ P _H ; Among them, the heat production power of the gas boiler: P _GB,h ＝η _GB P _gas,GB In the formula, P _GB,h is the heat production power of the gas boiler; η _GB represents the efficiency of the gas boiler; P _{gas, GB} represents the gas consumption power of the gas boiler; Step 3.2: According to the output P _F of the wind turbine unit, the electrical output P _CHP of the gas cogeneration unit and the electrical load P _E in the current period, determine whether the electrical load meets the system demand in the period t; the sign that the system meets the electrical load demand:

In the formula, when U _t =1, it means excess electric energy, and when U _t =0, it means insufficient electric energy; Among them, the generating power of the gas cogeneration unit is: P _CHP ＝η _CHP P _gas,CHP In the formula, η _CHP represents the electrical conversion efficiency of the gas cogeneration unit; If U _t = 1, that is, the electric load can meet the system demand during the t period, and the electric energy is surplus, proceed to step 3.3; if U _t = 0, that is, the electric load cannot meet the system demand during the t period, then jump to step 3.4; Step 3.3: If the power generation is too large and there is still a surplus after meeting the basic electric load, the system uses a power-to-gas device to convert the excess wind power output into natural gas, and stores the natural gas in a gas storage tank to judge the gas storage of the power-to-gas equipment Whether the tank storage capacity meets the gas storage conditions:

In the formula, when V _t = 1, it means that gas storage is possible, and when V _t = 0, it means that gas storage is not possible; S _s is the storage capacity of the power-to-gas gas storage tank in the current scheduling period, and S _s,min is the power-to-gas gas storage tank The minimum storage capacity inside, S _s,max is the maximum storage capacity inside the power-to-gas storage tank; The storage capacity of the gas storage tank of the power-to-gas equipment is:

△P＝P _S -P ₀ In the formula, K is the gas consumption per unit time of the compressor in the gas storage tank; _{P a} is the atmospheric pressure at the altitude where the power-to-gas gas storage tank is installed; The variation of P ₀ ; K _L is the comprehensive parameter of the internal pressure of the power-to-air gas storage tank during the current scheduling period; Q is the output gas flow rate of the power-to-gas gas storage tank during the current scheduling period; When V _t = 0, that is, the storage capacity of the gas storage tank of the power-to-gas equipment does not meet the gas storage conditions, then jump to step 4; if V _t = 1, it means that the capacity of the gas storage tank of the power-to-gas equipment meets the gas storage conditions, then set The excess natural gas converted from wind power is stored in the gas storage tank, and then skip to step 3.5; Among them, the electric energy consumed by the power-to-gas equipment is:

In the formula, P _P2G represents the power consumption of the power-to-gas equipment; H _g represents the calorific value of natural gas; η _P2G represents the conversion efficiency of the power-to-gas equipment; Step 3.4: If the electric load cannot meet the basic electric load demand of the system during the period t, judge whether the storage capacity of the gas storage tank of the power-to-gas device meets the gas discharge conditions; Electric energy is supplied to the electric load of the system, and then jump to step 3.5; if not, purchase electricity P grid from the _grid ; Described deflation condition is:

In the formula, when X _t = 1, it means deflation is possible, and when X _t = 0, it means that deflation is not possible; Among them, when the gas storage tank cannot release gas, it purchases electricity from the grid: P _grid ＝P _E -P _CHP -P _F In the formula, P _grid represents the electricity purchased from the grid when the gas storage tank cannot be released; Gas turbine power generation: P _GT ＝η _GT QH _g In the formula, _PGT represents the generating power of the gas turbine; _ηGT represents the conversion efficiency of the gas turbine; Step 3.5: Judging whether the current time period t has reached the power balance state:

In the formula, if Y _t = 1, the state of electric energy balance is reached, then jump to step 4; if Y _t = 0, that is, the state of electric energy balance cannot be reached, then purchase power P _grid from the grid until the state of electric energy balance is returned Step 4; Among them, when the electric energy is in a balanced state, the electricity purchased from the grid: P _grid ＝P _E -P _CHP -P _F -P _GT In the formula, P _grid represents the power purchased from the grid when the power balance is reached.

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