CN111817320A - Analysis method of peak shaving capacity of pumped storage power station considering the effect of evaporation - Google Patents

Abstract

The invention discloses a method for analyzing the peak regulation capability of a pumped-storage power station considering the effect of water evaporation. The evaporation of the power station in each period is included in the upper and lower reservoir models of the pumped-storage power station; the pumped-storage water volume model established in step 2 is introduced into the pumped-storage working state model and constraints, and the peak-shaving model of the pumped-storage power station is established ; Apply the peak regulation model of the pumped storage power station to the constraints of the microgrid system, and establish a microgrid system model that takes into account the impact of precipitation according to the objective function of the microgrid system model. The present invention can fully consider in the dry season or the arid area with large evaporation, finely model and analyze the regulation capacity of the pumped-storage power station, and on this basis, analyze the new energy consumption of the power grid, and improve the pumped-storage power Modeling accuracy of the power plant.

Description

Analysis method of peak shaving capacity of pumped storage power station considering the effect of evaporation

technical field

The invention relates to the technical field of new energy, in particular to a method for analyzing the peak-shaving capacity of a pumped-storage power station that takes into account the effect of water evaporation.

Background technique

Renewable resources are abundant and widely distributed in the northwestern region of my country. Vigorously developing new energy power generation is of great strategic significance to ensure my country's energy security, energy conservation and emission reduction, and to achieve sustainable development. With the continuous increase of its installed capacity, especially the development of distributed generation DG (distributed generation) such as wind power and photovoltaics, the problem of consumption has become a very important problem.

The use of energy storage devices can effectively improve the consumption of new energy and realize the "transfer" of energy in time. Compared with other energy storage methods, pumped storage has the characteristics of less capital investment, long equipment life, large energy storage scale, high conversion efficiency, mature technology, simple operating conditions, clean and environmental protection, etc., so it has been rapidly developed and widely used. It is the most mature and practical large-scale energy storage method in the current power system.

The key factors restricting the consumption of new energy are analyzed. The main considerations are the output range and climbing ability of thermal power units, and the "pumped" power range of pumped storage power stations.

Due to the consideration of existing pumped-storage power stations, the reservoir water volume of the pumped-storage power station is often not changed by default. When the water volume increases beyond a certain amount, due to the influence of the reservoir capacity constraints, this will limit and constrain the adjustment capacity of the pumped storage power station, which will lead to a decrease in the adjustment capacity of the pumped storage power station, thus affecting the consumption of new energy. , which in turn leads to a decline in the economics of the entire grid operation.

Therefore, how to provide a measurement method to calculate the impact of evaporation on the peak shaving capacity and new energy consumption capacity of the pumped storage power station, so as to improve the modeling accuracy of the pumped storage power station, is an urgent problem for those skilled in the art.

SUMMARY OF THE INVENTION

In view of this, the present invention provides a method for analyzing the peak regulation capacity of a pumped-storage power station that takes into account the effect of water evaporation, which can fully consider the adjustment capacity of the pumped-storage power station in dry seasons or areas with large evaporation. Modeling and analysis, and on this basis, analyze the new energy consumption of the power grid, and provide basic support for the economic optimal dispatch of the power grid.

In order to achieve the above object, the present invention provides the following technical solutions:

A method for analyzing the peak-shaving capacity of a pumped-storage power station considering the effect of water evaporation, comprising the following steps:

Step 1: Obtain the evaporation data of the pumped-storage power station reservoir area in different time periods;

Step 2, establish a pumped-storage water loss model, and include the evaporation in each period of the pumped-storage power station into the upper and lower reservoir models of the pumped-storage power station;

Step 3: Introduce the pumped-storage water volume model established in step 2 into the pumped-storage working state model and constraint conditions to establish a pumped-storage power station peak regulation model;

Step 4: Apply the peak regulation model of the pumped storage power station to the constraints of the microgrid system, and establish a microgrid system model that takes into account the effect of evaporation according to the objective function of the microgrid system model.

Preferably, in the second step, the model of the effect of the evaporation of the pumped-storage power station on the water volume of the reservoir is:

Q _(ev,k) = E _(ev,k) S

Q _(ev,k) is the value of evaporation increase of reservoir water volume in unit time; S is the average reservoir area in the calculation period.

Model of upper reservoir: V _(u,k) = -Q _(ev,k) +Q _(pump,k) -Q _(tur,k) +V _(u,k-1)

Model of the lower reservoir: V _(d,k) = -Q _(ev,k) -Q _(pump,k) -Q _(tur,k) +V _(d,k-1)

Gravitational potential energy and energy conversion model:

P _(pump,k) = η _pump ρQ _(pump,k) h

P _(tur,k) = η _tur ρQ _(tur,k) h

V _(u,k) and V _(d,k) are the actual storage capacity of the upper and lower reservoirs in the k period; Q _(ev,k) , Q _(pump,k) , Q _(tur,k) are the evaporation in the k period, respectively , the amount of water pumped and discharged; η _pump is the pump efficiency; P _(pump,k) is the pump power in the k period; η _tur is the generator set efficiency; P _{(tur, k)} is the generator set power in the k period; ρ is the water density; g is the acceleration of gravity; h is the head height of the reservoir.

Preferably, in the third step, the working state model is:

U _(tur,k) +U _(pump,k) ≤1

U _(pump,k) P _(pump,k) =P _(pump,k)

U _(tur,k) P _(tur,k) =P _(tur,k)

The water quantity transformation constraints of pumped storage power station water quantity are:

V _umin , V _umax , V _dmin , and V _dmax are the upper and lower boundaries of the storage capacity of the upper and lower reservoirs, respectively; ΔV _umax , ΔV _dmax are the maximum daily variation range of the storage capacity of the pumped storage power station. U _(tur,k) and U _(pump,k) are the working states of pumping and power generation of the pumped-storage power station, respectively. A value of 1 means it is in this state, and 0 means it does not belong to this state.

Preferably, in the step 4, the objective function of the microgrid system model considering the effect of evaporation is:

F=min∑(C _(c,k) P _(c,k) +C _(N,k) P _(N,k) )

C _(c,k) and C _(N,k) are the power generation cost of the thermal power plant and the cost of new energy abandonment, respectively, and the cost of new energy abandonment is the sum of the cost of wind abandonment and the cost of abandonment of light; P _(c,k) and P _(N,k) , respectively, the power generation of thermal power plants and the discarded power of new energy.

The constraints of the microgrid system model are:

与

分别为电厂的j参量在k时刻的发电量，理论出力最大值与最小值，其中j包括火电c，风电wind或光伏PV。P _(j,k)

and

are the power generation of the j parameter of the power plant at time k, the maximum and minimum theoretical output, where j includes thermal power c, wind power wind or photovoltaic PV.

Compared with the prior art, the advantages of a method for analyzing the peak regulation capability of a pumped storage power station that take into account the effect of water evaporation in the present invention are:

The invention carries out refined modeling and analysis on the regulation capacity of the pumped-storage power station, calculates the influence of evaporation on the peak-shaving capacity and the new energy consumption capacity of the pumped-storage power station with a more accurate measurement method, and improves the construction of the pumped-storage power station. model accuracy, so as to provide a reference for the power grid operation strategy; at the same time, this scheme makes up for the operating cost calculation error and the new energy consumption calculation error caused by the inaccuracy of the model in the existing pumped storage power station modeling, which can better evaluate the content of the power grid. Operational economics of a pumped-storage power plant model. If this method is applied to the design and planning evaluation, it will provide an economic reference for planning such as site selection and capacity determination of pumped storage power stations.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only It is an embodiment of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to the provided drawings without creative work.

Fig. 1 is the flow chart of the peak regulation capacity analysis method of pumped-storage power station that takes into account the effect of evaporation provided by the present invention;

FIG. 2 is an output diagram of each unit under working condition 1 provided by an embodiment of the present invention;

FIG. 3 is a consumption diagram of a new energy source under a working condition provided by an embodiment of the present invention;

FIG. 4 is an output diagram of each unit in working condition 2 provided by an embodiment of the present invention;

FIG. 5 is a consumption diagram of a new energy source in working condition two according to an embodiment of the present invention;

FIG. 6 is an output diagram of each unit in working condition three according to an embodiment of the present invention;

FIG. 7 is a consumption diagram of a new energy source under working condition three according to an embodiment of the present invention;

FIG. 8 is a comparison diagram of whether the water loss cost is considered or not according to an embodiment of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The embodiment of the invention discloses a method for analyzing the peak regulation capability of a pumped-storage power station considering the effect of water evaporation, which provides a method for accurately evaluating the new energy consumption capacity of the pumped-storage power station and the operation economy of the power grid including the pumped-storage power station. This method establishes the water volume model of pumped storage power station affected by seasonal water evaporation through statistical analysis of historical data. This method can be applied to the analysis of peak regulation capacity of the power system with pumped storage power station in different regions.

A method for analyzing the peak regulation capability of a pumped-storage power station considering the effect of water evaporation, the analysis method comprises the following steps:

S1. Determine the climatic conditions of the reservoir area, and accumulate and average the monthly evaporation data of the pumped-storage power station reservoir area and the historical year interval of the nearby area, so as to obtain the weighted average of the monthly evaporation of the pumped-storage power station reservoir area. Thus, the values of the evaporative amount in the i-th month are obtained as E ₁ , E ₂ , . . . , E _i , . . . , E ₁₂ . Compare the sizes of E ₁ , ..., E ₁₂ .

S2, find out the evaporation value of each time period, and the time interval is 15min. Select the weighted average of the evaporation of each month, average it to each time period, get the average evaporation of each time period, and multiply it by the evaporation probability, so as to obtain the evaporation at each moment. The specific formula is shown in (1).

Among them, E _(ev,k) is the evaporation of the pumped storage power station reservoir area in the k period, E _i is the monthly average evaporation, D is the total number of time periods in the month, and P _ev is the average value of the daily evaporation probability in the historical year interval (data pumped storage power station reservoir).

S3. Establish a pumped storage water loss model. Equation 2 is used to calculate the model of the effect of the evaporation of the pumped storage power station on the water volume of the reservoir. The evaporation of the pumped-storage power station in each time period is included in the upper and lower reservoir models of the pumped-storage power station, which can effectively improve the water volume accuracy of the pumped-storage power station model.

Q _(ev,k) = E _(ev,k) S(2)

Q _(ev,k) is the value of evaporation increase of reservoir water volume per unit time (m ³ ); S is the average reservoir area (m ² ) in the calculation period.

Model of Upper Reservoir:

V _(u,k) = -Q _(ev,k) +Q _(pump,k) -Q _(tur,k) +V _(u,k-1) (3)

Model of the lower reservoir:

V _(d,k) = -Q _(ev,k) -Q _(pump,k) -Q _(tur,k) +V _(d,k-1) (4)

Gravitational potential energy and energy conversion model:

P _(pump,k) = η _pump ρQ _(pump,k) h (5)

P _(tur,k) = η _tur ρQ _(tur,k) h (6)

V _(u,k) and V _(d,k) are the actual storage capacity of the upper and lower reservoirs in the k period; Q _(pr,k) , Q _(pump,k) , Q _(tur,k) are the evaporation, pumping, and releasing of water in the k period η _pump is the pump efficiency; P _{(pump, k)} is the pump power when k; η _tur is the generator set efficiency; P _{(tur, k)} is the generator set power; ρ is the water density, taken as 1000kg/ ^m ; g is the acceleration of gravity; h is the head height of the reservoir. The sampling time is 15min. From the upper reservoir model and the lower reservoir model, the calculation model of evaporation to the reservoir water volume is obtained, and the relationship between the pumped storage power generation and the pumped output and the reservoir water volume is obtained by combining the gravitational potential energy and the energy conversion model, and finally the pumped storage power generation is calculated. Control relationship of reservoir water volume affected by evaporation.

S4. Establish a peak regulation model of the pumped storage power station. The pumped-storage water volume model established by S3 is introduced into the pumped-storage working state model and constraints. Since the pumped-storage power station cannot work in the pump mode and the generator mode at the same time, it can be in the standby state at the same time, and the working state can be calculated using mathematics. relationship expression. See formula (7-9)

U _(tur,k) +U _(pump,k) ≤1 (7)

U _(pump,k) P _(pump,k) =P _(pump,k) (8)

U _(tur,k) P _(tur,k) = P _(tur,k) (9)

In order to ensure the safe, stable and normal operation of the pumped-storage power station, the pumped-storage power station needs to meet the storage capacity constraints. At the same time, the daily water volume of the pumped-storage power station is transformed. Show. Among them, the values of V _(u,k) and V _(d,k) are the values after considering the water loss in S3. For the previous modeling without considering the water loss, the model is more accurate.

V _umin , V _umax , V _dmin , V _dmax are the upper and lower boundaries of the storage capacity of the upper and lower reservoirs, respectively; ΔV _umax , ΔV _dmax are the maximum daily variation range of the storage capacity of the pumped storage power station, U _(tur,k) , U _(pump,k) are the working states of pumping and power generation of the pumped-storage power station, respectively. A value of 1 means it is in this state, 0 means it does not belong to this state, and the sampling time is 15 minutes.

S5. Apply the pumped-storage regulation model in S4 to the microgrid system to analyze the peak shaving capacity, and compare it with the new energy consumption results obtained by using a conventional model that does not consider the effect of evaporation.

The applied system model is composed of new energy sources—pumped storage—thermal power plants. The objective function of the microgrid system model considering the effect of evaporation is shown in Equation (11). In this model, it is considered that the operation of new energy and pumped storage power stations does not generate electricity generation costs.

F=min∑(C _(c,k) P _(c,k) +C _(N,k) P _(N,k) ) (11)

C _(c,k) and C _(N,k) are the power generation cost of the thermal power plant and the cost of new energy abandonment, respectively, and the cost of new energy abandonment is the sum of the cost of wind abandonment and the cost of abandonment of light; P _(c,k) and P _(N,k) , respectively, the power generation of thermal power plants and the discarded power of new energy.

The model is shown in the figure and the constraints are shown in Equation 12

The microgrid system considering the effect of evaporation, by adjusting the size of P _(pump,k) and P _(tur,k) , that is, the output of the pumped storage power station (including energy storage and power generation) and U _(tur,k) , the value of U _(pump,k) , that is, the working state of pumped storage, according to formulas (7) (8) (9) (12), so that the optimization objective (11) is optimal.

The new energy absorption capacity of the system is shown in Equation 13:

是k时段机组j的理论最大出力值，P_(j,k)是k时段机组j的实际出力值，两者相减为k时段的总弃用电量。P_N值越大则新能源弃用量越大，系统的新能源消纳能力越低。On this basis, compare the value of the total power consumption P _N in the new energy operation time of the new energy power station with and without the addition of the pumped storage power station, so as to compare the consumption of the new energy power station.

is the theoretical maximum output value of unit j in the k period, and P _{(j, k)} is the actual output value of the unit j in the k period. The larger the _PN value, the greater the amount of new energy discarded, and the lower the new energy consumption capacity of the system.

At the same time, the value of F of the additional pumped-storage power station and that without the additional pumped-storage power station, that is, the system operating cost, is compared and compared.

Take a microgrid with a pumped-storage power station in a certain area as an example, it is assumed that the area contains thermal power units, wind turbines, photovoltaic units, and pumped-storage units. In this example, the time precision is set to 15min, a total of 96 points per day, and the calculation period is 10 days, then the new energy and load sequence power curves of the main transformers under each main transformer within the 10-day operation period of the microgrid are obtained. Analyze and calculate the new energy consumption and operating cost under the three working conditions, and analyze the impact of seasonal water evaporation on the pumped storage power station according to the calculation results.

The details of each unit are shown in Table 1:

Table 1

The typical conditions chosen are as follows:

Condition 1: Consider the operation of the microgrid when the pumped storage power station does not work.

Condition 2: The operation of the microgrid when the output of the pumped storage power station is considered but the effect of evaporation is not considered.

Condition 3: When considering the output of the pumped storage power station and the influence of evaporation, the operation of the microgrid.

The results of calculating the evaluation index are shown in Table 2:

Table 2

Figure 2, Figure 4, and Figure 6 are the output area diagrams of various types of power sources under working conditions 1, 2, and 3. It can be seen that increasing the pumped storage can reduce the output of thermal power units to improve the operating economy of the microgrid; at the same time, the output area of wind power and photovoltaics Increase, the new energy absorption capacity increases; comparing Figure 4 with Figure 6, it can be seen that the evaporation of the pumped storage power station will lead to an increase in the climbing speed of the thermal power unit.

Figure 3, Figure 5, and Figure 7 are the new energy consumption curves of working conditions 1, 2, and 3, respectively. Comparing the theoretical output and actual output of new energy, the pumped storage power station can effectively reduce the rate of power abandonment and improve the consumption capacity of new energy.

As shown in Table 2, the pumped-storage power station can effectively improve the new energy consumption capacity; under relatively severe weather conditions (continuous drought and less rain, the probability of evaporation is high), through the model proposed in the present invention, the calculation results The abandonment rate of new energy sources increases, the absorption capacity decreases, and the operating cost of the system increases. Therefore, the modeling considering the effect of evaporation is of great significance for the evaluation of the utilization effect of the pumped storage power station and the proposal of the optimal operation strategy.

Figure 8 shows that if the total operating cost of the evaporative microgrid is not considered, there will be a large error in the calculation.

The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the various embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant part can be referred to the description of the method.

The above description of the disclosed embodiments enables any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (4)

1. a method for analyzing the peak regulation capability of a pumped storage power station in consideration of the influence of water evaporation, is characterized in that, comprises the steps: Step 1: Obtain the evaporation data of the pumped-storage power station reservoir area in different time periods; Step 2, establish a pumped-storage water loss model, and include the evaporation in each period of the pumped-storage power station into the upper and lower reservoir models of the pumped-storage power station; Step 3: Introduce the pumped-storage water volume model established in step 2 into the pumped-storage working state model and constraint conditions to establish a pumped-storage power station peak regulation model; Step 4: Apply the peak regulation model of the pumped storage power station to the constraints of the microgrid system, and establish a microgrid system model that takes into account the effect of evaporation according to the objective function of the microgrid system model. 2. the method for analyzing the peak regulation capacity of a pumped-storage power station considering the influence of water evaporation according to claim 1, it is characterized in that, in the described step 2, the model of the evaporation of the pumped-storage power station for the influence of the water volume of the reservoir is: : Q _(ev,k) = E _(ev,k) S Q _(ev,k) is the value of the reduction of the reservoir water volume due to evaporation in unit time; S is the average reservoir area in the calculation period. Model of upper reservoir: V _(u,k) = -Q _(ev,k) +Q _(pump,k) -Q _(tur,k) +V _(u,k-1) Model of the lower reservoir: V _(d,k) = -Q _(ev,k) -Q _(pump,k) -Q _(tur,k) +V _(d,k-1) Gravitational potential energy and energy conversion model: P _(pump,k) = η _pump ρQ _(pump,k) h P _(tur,k) = η _tur ρQ _(tur,k) h V _(u,k) and V _(d,k) are the actual storage capacity of the upper and lower reservoirs in the k period; Q _(ev,k) , Q _(pump,k) , Q _(tur,k) are the evaporation in the k period, respectively , the amount of water pumped and discharged; η _pump is the pump efficiency; P _(pump,k) is the pump power in the k period; η _tur is the generator set efficiency; P _{(tur, k)} is the generator set power in the k period; ρ is the water density; g is the acceleration of gravity; h is the head height of the reservoir. 3. The method for analyzing the peak-shaving capacity of a pumped-storage power station that takes into account the effect of water evaporation according to claim 1, wherein in the step 3, the working state model is: U _(tur,k) +U _(pump,k) ≤1 U _(pump,k) P _(pump,k) =P _(pump,k) U _(tur,k) P _(tur,k) =P _(tur,k) The water quantity transformation constraints of pumped storage power station water quantity are:

V _umin , V _umax , V _dmin , and V _dmax are the upper and lower boundaries of the storage capacity of the upper and lower reservoirs, respectively; ΔV _umax , ΔV _dmax are the maximum daily variation range of the storage capacity of the pumped storage power station. U _(tur,k) and U _(pump,k) are the working states of pumping and power generation of the pumped-storage power station, respectively. A value of 1 means it is in this state, and 0 means it does not belong to this state. 4. a kind of peak regulation capacity analysis method of pumped-storage power station considering the influence of water evaporation according to claim 1, it is characterized in that, in the described step 4, the objective function of the micro-grid system model considering the influence of evaporation is : F=min∑(C _(c,k) P _(c,k) +C _(N,k) P _(N,k) ) C _(c,k) and C _(N,k) are the power generation cost of the thermal power plant and the cost of new energy abandonment, respectively, and the cost of new energy abandonment is the sum of the cost of wind abandonment and the cost of abandonment of light; P _(c,k) and P _(N,k) are the power generation of thermal power plants and the discarded power of new energy sources, respectively. The constraints of the microgrid system model considering the effect of evaporation are:

P _(j,k) ,

and

are the power generation of the j parameter of the power plant at time k, the maximum and minimum theoretical output, where j includes thermal power c, wind power wind, and photovoltaic PV.

Images