CN113097996B - A load-saving and land-saving linkage dispatching method for electric heating and heat storage devices - Google Patents

Abstract

The invention discloses a load land-saving linkage scheduling method of an electric heating heat storage device, which mainly utilizes the characteristics of the electric heating heat storage device and the characteristics of photovoltaic and wind power output to make formulation, and comprises the following steps: (1) predicting the heat load demand of the future period of the region; (2) converting the thermal load into an electric load and establishing an electric heating heat storage power model; (3) weighting the heat storage load of the electric heating device; (4) and (5) establishing an electricity heating heat storage load land-saving linkage scheduling model. Aiming at the problem of wind abandoning and electricity limiting in the winter heating period of the regions, the invention saves and predicts the heating load demand in the future period, gives instructions to the electric heating and heat storage systems of all regions, fully utilizes the electric heating and heat storage modes of all regions and combines the characteristics of wind power and photoelectric treatment to adjust the heating power. And more reasonable peak shaving decision selection can be provided for power grid dispatching staff.

Description

A load-saving and land-saving linkage dispatching method for electric heating and heat storage devices

Technical field

The invention relates to an electric heating-heat storage combined operation method, and in particular to a load-saving and land-saving linkage dispatching method for an electric heating and heat storage device.

Background technique

At present, my country's wind power and photovoltaic installed capacity have always been in the world's leading position in scale and development speed. By the end of 2020, the installed wind power capacity reached 281 million kW and the photovoltaic installed capacity reached 253 million kW. Although clean energy brings a lot of convenience to our lives, problems such as the uncontrollability of wind power and photovoltaic power generation, and the incomplete construction of wind power and photovoltaic power grid transmission channels have led to serious wind and light abandonment phenomena. Electric heating and heat storage equipment is an ideal equipment to solve this problem. It can be used as a power source to transmit electricity to the outside world, and at the same time, it can be used as a load to absorb electricity. If it is used flexibly, then the electric heating and heat storage device will play a vital role in protecting the power grid. Safe operation has important practical significance. The comprehensive utilization of electric heating and heat storage will be an important part of realizing a completely clean energy supply.

At present, large-scale investment and use of electric heating and heat storage devices still faces huge technical challenges and cost constraints. The winter heating period in the northern region is about 4 to 5 months, and the traditional heating method is to use coal-fired units to generate heat and power. Due to the constraints of the "heat-based power generation" method, the adjustment margin of the heating unit is very small. However, winter in the north is also the season when photovoltaic and wind power are booming. This is also an important factor causing the abandonment of wind and light. If Change coal-fired heating to electric heating, adopt the method of heat storage, adjust the heating power according to the output characteristics of wind power and photovoltaic, absorb excess electricity and store heat during low load periods, and release heat during peak load periods to reduce heat supply The amount of units started can greatly improve the level of renewable energy consumption and peak load regulation. Therefore, there is an urgent need for an operation method and system for electric heating and heat storage load to save space and combine with rapid peak shaving to solve the above problems.

Contents of the invention

The purpose of the present invention is to provide a load-saving and land-saving linkage dispatching method for electric heating and heat storage devices. This method is formulated by utilizing the characteristics of electric heating and heat storage devices and the output characteristics of photovoltaic and wind power. It utilizes electric heating and heat storage methods and Combining the characteristics of wind power and photoelectric processing, it adjusts the heating power and absorbs excess electricity. While increasing the power load, it reduces the amount of heating units that are turned on.

In order to solve the problems existing in the prior art, the present invention adopts the following technical solutions:

A load-saving and land-saving linkage dispatching method for electric heating and heat storage devices, including the following steps:

① Forecast the regional heat load demand in the future;

②Convert thermal load into electric load and establish an electric heating and storage power model;

③ Weight the heat storage load of the electric heating device;

④ Establish a provincial and local linkage dispatch model for electric heating and heat storage loads.

Further, the step ① predicting the regional heat load demand in future periods includes the following steps: according to the heat load demand characteristics of different periods of the day, the day is divided into different dispatchable periods to realize the electric heating and heat storage load. Scheduling, the model of the energy gap is:

Δp ₁ =p ₂ -p ₁ ;

In the formula, P ₂ is the predicted heat load power in the next period, and P ₁ is the heat load power in the current period;

Q is the predicted gap energy in the next period, t ₀ =t ₂ -t ₁ , and t ₀ is the minimum control period.

Further, the step ② converts the thermal load into an electric load and establishes an electric heating and storage power model, including:

Preprocessing of heat load, converting heat load into power supply load:

P _hload is the thermal load power, Q is the predicted gap energy in the next period, and t ₀ is the minimum control period;

The electric heating and heat storage power model is:

P _e2h =P _hload +P _hs ;

P _e2h is electric heating power; P _hload is heat load (converted into power supply load); P _hs is heat storage power, heat storage is positive and heat release is negative.

Further, the step ③ weighting the heat storage load of the electric heating device includes the following steps:

According to the installation characteristics and working characteristics of the electric heating and heat storage device, and according to the importance of the user's heating load, the importance grade coefficient a of the heat load, the real-time heat storage degree of the electric heating and heat storage device b, and the electric heating device itself can be formulated Working characteristics, the shortest working time and the minimum interval time between adjacent dispatching moments are used to formulate the user-friendliness c of electric heating, the control response accuracy d, and the fitted electric heating controllable coefficient model A=a+b+c+d; when A When _min ≤ A ≤ A _max , the electric heating and heat storage device can be scheduled;

The sum of adjustable electric heating power in each region:

In the formula, x _i,j represents the status of the i-th Taiwan power heating device at the j-th dispatch time, correspondingly When x _i,j = 1, it means that the i-th Taipower heating device can be scheduled at the j-th scheduling time. When x _i,j = 0, it means that the i-th Taipei heating device will exit at the j-th scheduling time. Cannot be scheduled.

Further, the heat storage capacity model of the electric heating and heat storage device is:

S _i (j+1)=S _i (j)+P _{hs_i} (j)Δt-η×S _i (j);

In the formula: S _i (j+1) and S _i (j) are the accumulated heat storage capacity MWh of the heat storage system in the j+1 and j dispatching stages of the i-th power heating equipment respectively, and P _{hs_i} (j) is stage j The output power of the heat storage system; Δt is the scheduling period of the heat storage system; eta is the heat storage efficiency of the heat storage system within Δt time

Further, the step ④ establishes the provincial and local linkage dispatch model of electric heating and heat storage load as follows:

When the heat load demand gap in the jth period is predicted to be Q _j , the objective function of the electric heating and heat storage load dispatching scheme is:

The electric heating and heat storage load dispatching scheme will absorb excess electricity and store heat during low load periods, and release heat during peak load periods, reducing the amount of heating units started to cut peaks and fill valleys, making it easier for the power grid to formulate power generation dispatch plans.

Further, the constraints corresponding to step ④ establishing the electric heating and heat storage load-provincial linkage dispatch model include system heat load constraints, heat storage device capacity constraints and system operation safety constraints;

The system thermal load constraints are expressed as:

Among them, eta represents the heat storage efficiency of the heat storage system in Δt time, and Q represents the gap energy of the heat load within the dispatch period; the heat storage device capacity constraint is expressed as:

In the formula, _Si is the rated capacity of the i-th heat storage device, Δt is the minimum scheduling time step,

S _max and S _min are the upper and lower limits of the heat storage system capacity; S(t) is the capacity value of the heat storage system in the dispatch stage.

The advantages and beneficial effects of the present invention are:

The present invention is a land-saving linkage dispatching method for the load of electric heating and heat storage devices, which includes the following steps: provincial dispatching predicts the heating load demand in future periods, and secondly, making full use of the spatial advantages of widely distributed electric heating and heat storage devices in various regions, And the electric heating and heat storage device absorbs excess electricity and stores heat when the photovoltaic is abundant, and then releases heat while increasing the electric load, reducing the number of heating units to start. Finally, specific regulations are issued for the electric heating and heat storage systems in various cities. Load dispatching instructions provide more reasonable peak-shaving decision-making options for power grid dispatching staff. The method of the invention absorbs excess electricity and stores heat during the low load period, releases heat during the peak load period, reduces the startup amount of the heating unit, cuts peaks and fills valleys, and stabilizes power generation.

Description of the drawings

The present invention will be further described in detail below in conjunction with the accompanying drawings:

Figure 1 is a diagram showing the relationship between heat load, electric heating and storage devices and the power grid;

Figure 2 is a flow chart of a load-saving and land-saving linkage dispatching method for an electric heating and heat storage device according to the present invention.

Detailed ways

The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, features and effects of the present invention.

As shown in Figures 1 and 2, the present invention provides a load-saving and land-saving linkage dispatching method for an electric heating and heat storage device. The electric heating and heat storage device mainly consists of an electric heating element, a high-temperature energy storage body, a high-temperature heat exchanger, and a heat exchanger. It consists of an output controller, a high-temperature insulation shell and an automatic control device. This method mainly uses the characteristics of the electric heating and heat storage device and the output characteristics of photovoltaic and wind power to formulate it, including the following steps:

① Forecast the regional heat load demand in the future;

②Convert thermal load into electric load and establish an electric heating and storage power model;

③ Weight the heat storage load of the electric heating device;

④ Establish a provincial and local linkage dispatch model for electric heating and heat storage loads.

The step ① predicting the heat load demand in the region in the future includes the following steps: According to the characteristics of people's daily life activities in the region, the highest demand for heat load is generally at night, and due to daytime lighting and other conditions, the daily heat load demand is relatively high. The low hours are generally from noon to afternoon. This characteristic of heat load is exactly opposite to the output characteristics of photovoltaic and wind power. If the future heat load is accurately predicted, electric heating devices can be used to store heat when photovoltaic and wind power are abundant, and then release heat at night when the heat load demand increases. According to the heat load demand characteristics at different times of the day, the day is divided into different dispatchable periods to realize the dispatch of electric heating and heat storage loads. The energy gap model is:

Δp ₁ =p ₂ -p ₁ ;

In the formula, P ₂ is the predicted heat load power in the next period, and P ₁ is the heat load power in the current period;

Q is the predicted gap energy in the next period, t ₀ =t ₂ -t ₁ , and t ₀ is the minimum control period.

The step ② converts the thermal load into an electric load and establishes an electric heating and storage power model, including:

Preprocessing of heat load, converting heat load into power supply load:

P _hload is the thermal load power, Q is the predicted gap energy in the next period, and t ₀ is the minimum control period;

The electric heating and heat storage power model is:

P _e2h =P _hload +P _hs ;

P _e2h is the electric heating power; Ph _load is the heat load, which has been converted into power supply load at this time; P _hs is the heat storage power, heat storage is positive and heat release is negative.

The step ③ weighting the heat storage load of the electric heating device includes the following steps:

According to the installation characteristics and working characteristics of the electric heating and heat storage device, and according to the importance of the user's heating load, the importance grade coefficient a of the heat load, the real-time heat storage degree of the electric heating and heat storage device b, and the electric heating device itself can be formulated Working characteristics, the shortest working time and the minimum interval time between adjacent dispatching moments are used to formulate the user-friendliness c of electric heating, the control response accuracy d, and the fitted electric heating controllable coefficient model A=a+b+c+d; when A When _min ≤ A ≤ A _max , the electric heating and heat storage device can be scheduled;

The sum of adjustable electric heating power in each region:

In the formula, x _i,j represents the status of the i-th Taiwan power heating device at the j-th dispatch time, correspondingly When x _i,j = 1, it means that the i-th Taipower heating device can be scheduled at the j-th scheduling time. When x _i,j = 0, it means that the i-th Taipei heating device will exit at the j-th scheduling time. Cannot be scheduled.

The heat storage capacity model of the electric heating and heat storage device is:

S _i (j+1)=S _i (j)+P _{hs_i} (j)Δt-η×S _i (j);

In the formula: S _i (j+1) and S _i (j) are the accumulated heat storage capacity MWh of the heat storage system in the j+1 and j dispatching stages of the i-th power heating equipment respectively, and P _{hs_i} (j) is stage j The output power of the heat storage system; Δt is the scheduling period of the heat storage system; eta is the heat storage efficiency of the heat storage system within Δt time. The heat storage system will have heat leakage loss during Δt time.

The step ④ establishes the provincial and local linkage dispatch model of electric heating and heat storage load as follows:

When the heat load demand gap in the jth period is predicted to be Q _j , the objective function of the electric heating and heat storage load dispatching scheme is:

The electric heating and heat storage load dispatching plan will increase the electricity load during valley periods, reduce the heating load of cogeneration units during peak periods, smooth the peak and valley differences of the power grid, stabilize power generation, and make it easier for the grid to formulate power generation dispatching plans.

The constraints corresponding to step ④ establishing the electric heating and heat storage load-provincial linkage dispatch model include system heat load constraints, heat storage device capacity constraints, and system operation safety constraints;

The system thermal load constraints are expressed as:

Among them, eta represents the heat storage efficiency of the heat storage system in Δt time. The heat storage system will have heat leakage loss in Δt time. Q represents the gap energy of the heat load during the dispatch period; the heat storage device capacity constraint is expressed as:

In the formula, _Si is the rated capacity of the i-th heat storage device, Δt is the minimum scheduling time step,

S _max and S _min are the upper and lower limits of the heat storage system capacity; S(t) is the capacity value of the heat storage system in the dispatch stage.

The above are the preferred embodiments of the present invention. Those skilled in the technical field to which the present invention belongs can make various modifications or supplements to the specific embodiments described above. These modifications or supplements should also be regarded as protection of the present invention. scope.

Claims (4)

1. A load-saving and land-saving linkage dispatching method for electric heating and heat storage devices, which is characterized by including the following steps: ① Forecast the regional heat load demand in the future; ②Convert thermal load into electric load and establish an electric heating and storage power model; ③ Weight the heat storage load of the electric heating device; ④Establish a provincial and local linkage dispatch model for electric heating and heat storage loads; The step ③ weighting the heat storage load of the electric heating device includes the following steps: According to the installation characteristics and working characteristics of the electric heating and heat storage device, and according to the importance of the user's heating load, the importance grade coefficient a of the heat load, the real-time heat storage degree of the electric heating and heat storage device b, and the electric heating device itself can be formulated Working characteristics, the shortest working time and the minimum interval time between adjacent dispatching moments are used to formulate the user-friendliness c of electric heating, the control response accuracy d, and the fitted electric heating controllable coefficient model A=a+b+c+d; when A When _min ≤ A ≤ A _max , the electric heating and heat storage device can be scheduled; The sum of adjustable electric heating power in each region: In the formula, x _i,j represents the status of the i-th Taiwan power heating device at the j-th dispatch time, correspondingly When x _i,j = 1, it means that the i-th Taipower heating device can be scheduled at the j-th scheduling time. When x _i,j = 0, it means that the i-th Taipei heating device will exit at the j-th scheduling time. Cannot be scheduled; The heat storage capacity model of the electric heating and heat storage device is: S _i (j+1)=S _i (j)+P _{hs_i} (j)Δt-η×S _i (j); In the formula: S _i (j+1) and S _i (j) are the accumulated heat storage capacity MWh of the heat storage system in the j+1 and j dispatching stages of the i-th power heating equipment respectively, and P _{hs_i} (j) is stage j The output power of the heat storage system; Δt is the scheduling period of the heat storage system, h; η is the heat storage efficiency of the heat storage system within Δt time; The step ④ establishes the provincial and local linkage dispatch model of electric heating and heat storage load as follows: When the heat load demand gap in the jth period is predicted to be Q _j , the objective function of the electric heating and heat storage load dispatching scheme is: The electric heating and heat storage load dispatching plan will increase the electricity load during valley periods, reduce the heating load of cogeneration units during peak periods, smooth the peak and valley differences of the power grid, stabilize power generation, and make it easier for the grid to formulate power generation dispatching plans. 2. A load-saving and land-saving linkage dispatching method for electric heating and heat storage devices according to claim 1, characterized in that: the step (1) predicting the regional heat load demand in future periods includes the following steps: according to different periods of the day Regarding the heat load demand characteristics, the day is divided into different dispatchable periods to realize the dispatch of electric heating and heat storage loads. The energy gap model is: Δp ₁ =p ₂ -p ₁ ; In the formula, P ₂ is the predicted heat load power in the next period, and P ₁ is the heat load power in the current period; Q is the predicted gap energy in the next period, t ₀ =t ₂ -t ₁ , and t ₀ is the minimum control period. 3. A load-saving linkage dispatching method for electric heating and heat storage devices according to claim 1, characterized in that: the step (2) converts the thermal load into an electric load and establishes an electric heating and storage power model, including : Preprocessing of heat load, converting heat load into power supply load: P _hload is the thermal load power, Q is the predicted gap energy in the next period, and t ₀ is the minimum control period; The electric heating and heat storage power model is: P _e2h =P _hload +P _hs ; P _e2h is the electric heating power; P _hload is the heat load; P _hs is the heat storage power. The heat storage is positive and the heat release is negative. 4. A load-saving and land-saving linkage dispatching method for electric heating and heat storage devices according to claim 1, characterized in that: the constraint conditions corresponding to the step ④ establishing the electric heating and heat storage load and land-saving linkage dispatching model include the system Thermal load constraints, thermal storage device capacity constraints and system operation safety constraints; The system thermal load constraints are expressed as: Among them, eta represents the heat storage efficiency of the heat storage system in Δt time, and Q represents the gap energy of the heat load within the dispatch period; the heat storage device capacity constraint is expressed as: In the formula, _Si is the rated capacity of the i-th heat storage device, Δt is the minimum scheduling time step, S _max and S _min are the upper and lower limits of the heat storage system capacity; S(t) is the capacity value of the heat storage system in the dispatch stage.