A medium- and long-term electricity decomposition method taking into account the uncertainty of new energy sources

Abstract

The purpose of the present invention is to provide a medium- and long-term electricity decomposition method taking into account the uncertainty of new energy. The system supports the consideration of the uncertainty characteristics of power generation when large-scale new energy is connected to the power grid, establishes a medium- and long-term electricity rolling balance analysis method, and improves the availability of medium- and long-term decomposition plans and the accuracy of medium- and long-term electricity balance analysis.

Description

Technical Field

[0001] The present invention belongs to the field of power system analysis, and in particular relates to a medium- and long-term power quantity decomposition method taking into account the uncertainty of new energy. Background Art

[0002] my country's wind power and photovoltaic power have continued to develop rapidly in recent years. The rapid development of new energy has injected new vitality into China's economic development and alleviated the energy crisis and environmental pressure to a certain extent. However, in recent years, my country has faced increasingly serious problems of wind and solar power abandonment, which has seriously affected the healthy development of my country's new energy industry. In order to promote the consumption of new energy, various regions have proposed various measures, among which medium- and long-term electricity trading is an active and effective means. However, the execution and decomposition of trading electricity needs to take into account the characteristics of new energy power generation and multiple factors in policy and technology, which makes it difficult to execute electricity decomposition and makes it difficult for the dispatching department to formulate a reasonable power generation plan.

[0003] Domestic power production and dispatching have long been under the planning system. First, the government department in charge formulates and determines the annual power generation plan of power plants (or units) based on the annual economic growth forecast and power balance, taking into account the national energy conservation and emission reduction, resource optimization and other policies and unit operation conditions; the power dispatching agency compiles the operation mode of each dispatching cycle of the power grid according to the load and safety requirements of the power grid, and decomposes and executes the annual planned power. Due to the uncertainty of medium- and long-term system load forecasts and the need for lean dispatching, the decomposition and execution of the annual power generation plan is continuously adjusted according to the actual operation of the power grid.

[0004] The existing decomposition of medium- and long-term electricity mainly focuses on the decomposition of deterministic contract electricity. The traditional medium- and long-term electricity decomposition mainly considers the annual contract completion progress and the load rate of power plants, but does not take into account the scheduling executability of the power generation plan, nor the impact of various uncertain factors such as new energy and load demand during the execution of the plan. The few studies that consider the uncertainty of new energy access and load do not consider the impact of uncertainty in the medium and long term. They either take the predicted values ​​of new energy and load as boundary conditions, or only consider the impact of uncertainty in the day-ahead plan and intraday rolling stage. There is a certain gap with the actual scheduling needs of existing large-scale uncertain new energy access, and the engineering application value is limited. Therefore, with the rapid development of new energy, the previous power decomposition method cannot adapt to the complex requirements under the new situation, and it is necessary to propose a medium- and long-term power balance analysis method that considers the uncertainty of new energy generation. Summary of the invention

[0005] Purpose of the invention: The purpose of the present invention is to provide a medium- and long-term electricity decomposition method taking into account the uncertainty of new energy. The system supports the consideration of the uncertainty characteristics of power generation when large-scale new energy is connected to the power grid, establishes a medium- and long-term electricity rolling balance analysis method, and improves the availability of medium- and long-term decomposition plans and the accuracy of medium- and long-term electricity balance analysis.

[0006] Technical solution: To achieve the purpose of the present invention, the technical solution adopted by the present invention is: a method for decomposing electric power within a preset time period taking into account the uncertainty of new energy sources, the method comprising the following steps:

[0007] Step A, using the annual and monthly historical renewable energy power generation data and the linear extrapolation method, obtain the renewable energy power generation forecast result Xi within a preset time period;

[0008] Step B, calculating the variance of the new energy power generation and the new energy power generation forecast result through historical data, and forming a normal distribution of the new energy power generation forecast;

[0009] Step C: for the new energy power generation prediction data, different new energy power generation sequences are divided by normal distribution to form a new energy power generation sequence X;

[0010] Step D: perform load forecasting based on historical load data of the power grid to obtain load forecast data LF, and use the load forecast data LF to subtract the new energy generation sequence X to form a conventional unit generation curve sequence L;

[0011] Step E: Calculate the transaction power decomposition curve of each load sequence according to the conventional unit load sequence, grid balance and unit output constraints to form a decomposition sequence G;

[0012] Step F: perform average calculation on the decomposition sequence G to calculate the final power decomposition result.

[0013] Furthermore, the step A specifically includes the following steps: for a given year and month of new energy power generation historical data, taking the minimum absolute difference between the fitted value and the actual value as the objective function, establishing a new energy linear extrapolation function, using the linear extrapolation method to perform load forecasting, and obtaining new energy power generation forecast data within the time period for which power decomposition is required. The medium and long term of the present invention can be a custom pre-set time period.

[0014] Furthermore, the step B specifically includes the following steps:

[0015] B1. The predicted power generation of new energy is calculated in accordance with the normal distribution, and the predicted power generation of new energy Xi is taken as the expected value of the normal distribution;

[0016] B2. Calculate the variance e of the historical load data and the predicted data of new energy power generation through the historical data of new energy power generation, and use it as the variance e of the normal distribution of new energy power generation to determine the left boundary Xi-3e and the right boundary Xi+3e of the predicted value of new energy power generation.

[0017] Furthermore, the step C comprises the following steps: according to the normal distribution, the power generation sequence of the new energy is taken as X, namely Xi, Xi-e, Xi+e, Xi+2e, Xi-2e, Xi+3e, Xi-3e.

[0018] Furthermore, step D includes the following steps: using the historical load curve and the linear extrapolation method to obtain the load forecast curve LF for the time period where power decomposition is required, and subtracting the new energy power generation sequence X from the load forecast curve LF, i.e., Xi, Xi-e, Xi+e, Xi+2e, Xi-2e, Xi+3e, Xi-3e, and the result is the power generation curve sequence L of the conventional units without new energy power generation, i.e., L0, L1, L2, L3, L4, L5, L6.

[0019] Further, the step E comprises the following steps:

[0020] E1: Take the power generation curve L0 of the conventional unit and allocate the medium- and long-term electricity according to the proportion of the power generation curve of the conventional unit;

[0021] Wit=Wi*Qt / Q

[0022] Q is the total amount of electricity in the time period when L0 needs to decompose the electricity, Qt is the electricity in a single time period t in the time period when L0 needs to decompose the electricity, Wi is the total electricity in the time period to be decomposed of the unit to be decomposed, Wit is the electricity in a single time period t in the time period when the unit needs to decompose the electricity, t=1,...N, N is the number of time periods for electricity decomposition;

[0023] Starting from the first allocated time slot and continuing until the last time slot N, proceed as follows:

[0024] E2: According to the decomposition result Wit, according to the maintenance plan of the conventional unit, make corrections. When there is maintenance in this period, the unit power during the maintenance period is allocated to other non-maintenance periods of the unit according to the power generation ratio, and the unit's corrected power decomposition result Wit1 is obtained;

[0025] E3: Determine whether the power of each unit exceeds the limit during the period. If it does, calculate the over-limit power ΔQ, and distribute the over-limit power to other units in the same period according to the proportion, and obtain the corrected power decomposition result Wit2 of the unit;

[0026] E4: reallocate the adjustment amount of the unit in this period according to the power generation of the unit in subsequent periods until N periods are allocated, and obtain the unit's revised decomposition result Wit3 to ensure that the total power remains unchanged;

[0027] E5: Through E1, E2, E3, and E4, a decomposition result G0 within a preset time period of the unit is calculated, that is, Wit3, t=1, ...N, N is the number of time periods for power decomposition;

[0028] E6: Take other power generation curves L1, L2, L3, L4, L5, L6 of conventional units respectively, repeat steps E1, E2, E3, E4, E5, calculate the decomposition results of medium- and long-term transactions of the units respectively, and form a medium- and long-term transaction decomposition sequence G, i.e. G0, G1, G2, G3, G4, G5, G6.

[0029] Furthermore, the step F includes: according to the previously calculated medium- and long-term decomposition sequence G, i.e., G0, G1, G2, G3, G4, G5, G6, averaging the above decomposition sequence according to the corresponding time period, and calculating the power decomposition curve of the generator set under the uncertainty sequence of new energy power generation.

[0030] Beneficial effects: Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0031] The technical solution of the present invention determines the uncertainty characteristics of renewable energy generation based on spatiotemporal distribution, and proposes a medium- and long-term power decomposition calculation step taking into account the uncertainty of renewable energy. The invention can provide a medium- and long-term power decomposition optimization method taking into account the uncertainty of renewable energy, making the calculation more efficient and faster, and improving the availability of the medium- and long-term decomposition plan and the accuracy of the medium- and long-term power balance analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a flow chart of the medium- and long-term power decomposition of a single output sequence taking into account the uncertainty of new energy sources according to the present invention;

[0033] Figure 2 This is a schematic diagram of a medium- and long-term electric power decomposition process taking into account the uncertainty of new energy sources according to the present invention. DETAILED DESCRIPTION

[0034] The following is a detailed description with reference to the accompanying drawings and embodiments.

[0035] The present invention proposes a medium- and long-term power decomposition method taking into account the uncertainty of new energy sources. Figure 1 As shown, the following steps are included:

[0036] 1. Establish a probability prediction sequence for new energy power generation:

[0037] a. Based on the annual and monthly historical renewable energy power generation data, the linear regression method is used to obtain renewable energy power generation forecast data that can reflect the changes in renewable energy power generation;

[0038] b. Based on the predicted data of new energy power generation, take it as the center Xi of the possible value range of new energy power generation;

[0039] c. Calculate the variance e between the historical load data and the forecast data of renewable energy power generation through the historical data of renewable energy power generation;

[0040] d. According to the characteristics of renewable energy power generation, the analysis is based on the assumption that renewable energy power generation is in normal distribution, that is, renewable energy power generation is considered to obey N(Xi,e 2 )distributed.

[0041] 2. Perform similar fitting and correction on the historical load data to obtain the annual load forecast curve LF.

[0042] 3. Take the output within different ranges of new energy to form a new energy processing sequence X (Xi, Xi-e, Xi+e, Xi+2e, Xi-2e, Xi+3e, Xi-3e).

[0043] 4. Subtract the new energy generation sequence X from the load curve LF, and the result is the power generation curve sequence L (L0, L1, L2, L3, L4, L5, L6) of the conventional thermal power units without new energy generation.

[0044] 5. According to the power generation curve sequence of conventional thermal power units, select the sequences (L0, L1, L2, L3, L4, L5, L6) in order to decompose the medium and long-term electricity. The decomposition method is as follows:

[0045] E1: Take the power generation curve L0 of the conventional unit and allocate the medium- and long-term electricity according to the proportion of the power generation curve of the conventional unit;

[0046] Wit=Wi*Qt / Q

[0047] Q is the total amount of electricity in the time period when L0 needs to decompose the electricity, Qt is the electricity in a single time period t in the time period when L0 needs to decompose the electricity, Wi is the total electricity in the time period to be decomposed of the unit to be decomposed, Wit is the electricity in a single time period t in the time period when the unit needs to decompose the electricity, t=1,...N, N is the number of time periods for electricity decomposition;

[0048] Starting from the first allocated time slot and continuing until the last time slot N, proceed as follows:

[0049] E2: According to the decomposition result Wit, according to the maintenance plan of the conventional unit, make corrections. When there is maintenance in this period, the unit power during the maintenance period is allocated to other non-maintenance periods of the unit according to the power generation ratio, and the unit's corrected power decomposition result Wit1 is obtained;

[0050] E3: Determine whether the power of each unit exceeds the limit during the period. If it does, calculate the over-limit power ΔQ, and distribute the over-limit power to other units in the same period according to the proportion, and obtain the corrected power decomposition result Wit2 of the unit;

[0051] E4: reallocate the adjustment amount of the unit in this period according to the power generation of the unit in subsequent periods until N periods are allocated, and obtain the unit's revised decomposition result Wit3 to ensure that the total power remains unchanged;

[0052] E5: Through E1, E2, E3, and E4, a decomposition result G0 within a preset time period of the unit is calculated, that is, Wit3, t=1, ...N, N is the number of time periods for power decomposition;

[0053] E6: Take other power generation curves L1, L2, L3, L4, L5, L6 of conventional units respectively, repeat steps E1, E2, E3, E4, E5, calculate the decomposition results of medium- and long-term transactions of the units respectively, and form a medium- and long-term transaction decomposition sequence G, i.e. G0, G1, G2, G3, G4, G5, G6.

[0054] 6. According to the medium- and long-term decomposition sequence G calculated previously, namely G0, G1, G2, G3, G4, G5, and G6, the average value of the above decomposition sequence is calculated according to the corresponding time period to calculate the power decomposition curve of the generator set under the uncertainty sequence of new energy power generation.

[0055] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for decomposing electric power within a preset time period taking into account the uncertainty of new energy sources, characterized in that: The method comprises the following steps: Step A, using the annual and monthly historical renewable energy power generation data and the linear extrapolation method, obtain the renewable energy power generation forecast result Xi within a preset time period; Step B, calculating the variance of the new energy power generation and the new energy power generation forecast result through historical data, and forming a normal distribution of the new energy power generation forecast; Step C: for the new energy power generation prediction data, different new energy power generation sequences are divided by normal distribution to form a new energy power generation sequence X; Step D: perform load forecasting based on historical load data of the power grid to obtain load forecast data LF, and use the load forecast data LF to subtract the new energy generation sequence X to form a conventional unit generation curve sequence L; Step E: Calculate the power decomposition curve of each load sequence according to the conventional unit load sequence and the power generation constraint of the unit to form a decomposition sequence G; Step F, performing average calculation on the decomposition sequence G to calculate the final power decomposition result; The step D comprises the following steps: based on the historical load curve, a load forecast curve LF in the time period where power decomposition is required is obtained by a linear extrapolation method, and the load forecast curve LF is subtracted from the new energy power generation sequence X, i.e., Xi, Xi-e, Xi+e, Xi+2e, Xi-2e, Xi+3e, Xi-3e, and the result is a power generation curve sequence L of conventional units without new energy power generation, i.e., L0, L1, L2, L3, L4, L5, L6; The step E comprises the following steps: E1: Take the power generation curve L0 of the conventional unit and allocate the medium- and long-term electricity according to the proportion of the power generation curve of the conventional unit; Wit=Wi*Qt / Q Q is the total amount of electricity in the time period when L0 needs to decompose the electricity, Qt is the electricity in a single time period t in the time period when L0 needs to decompose the electricity, Wi is the total electricity in the time period to be decomposed of the unit to be decomposed, Wit is the electricity in a single time period t in the time period when the unit needs to decompose the electricity, t=1,...N, N is the number of time periods for electricity decomposition; Starting from the first allocated time slot and continuing until the last time slot N, proceed as follows: E2: According to the decomposition result Wit, according to the maintenance plan of the conventional unit, make corrections. When there is maintenance in this period, the unit power during the maintenance period is allocated to other non-maintenance periods of the unit according to the power generation ratio, and the unit's corrected power decomposition result Wit1 is obtained; E3: Determine whether the power of each unit exceeds the limit during the period. If it does, calculate the over-limit power ΔQ, and distribute the over-limit power to other units in the same period according to the proportion, and obtain the corrected power decomposition result Wit2 of the unit; E4: reallocate the adjustment amount of the unit in this period according to the power generation of the unit in subsequent periods until N periods are allocated, and obtain the unit's revised decomposition result Wit3 to ensure that the total power remains unchanged; E5: Through E1, E2, E3, and E4, a decomposition result G0 within a preset time period of the unit is calculated, namely, Wit3, t=1, ...N, where N is the number of time periods for power decomposition; E6: Take other power generation curves L1, L2, L3, L4, L5, L6 of the conventional units respectively, repeat steps E1, E2, E3, E4, E5, and calculate the decomposition results of the units within the preset time period respectively to form a decomposition sequence G, i.e., G0, G1, G2, G3, G4, G5, G6.

2. According to claim 1, a method for decomposing electric power within a preset time period taking into account the uncertainty of new energy sources, characterized in that: The step A specifically includes the following steps: for a given year or month of new energy power generation historical data, taking the minimum absolute difference between the fitted value and the actual value as the objective function, establishing a new energy linear extrapolation function, using the linear extrapolation method to perform load forecasting, and obtaining new energy power generation forecast data within the time period for which power decomposition is required.

3. A method for decomposing electric power within a preset time period taking into account the uncertainty of new energy sources according to claim 1 or 2, characterized in that: The step B specifically comprises the following steps: B1. The predicted power generation of new energy is calculated in accordance with the normal distribution, and the predicted power generation of new energy Xi is taken as the expected value of the normal distribution; B2. Calculate the variance e of the historical load data and the predicted data of new energy power generation through the historical data of new energy power generation, and use it as the variance e of the normal distribution of new energy power generation to determine the left boundary Xi-3e and the right boundary Xi+3e of the predicted value of new energy power generation.

4. According to claim 3, a method for decomposing medium- and long-term power taking into account the uncertainty of new energy sources is characterized in that: The step C comprises the following steps: according to the normal distribution, the power generation sequence of the new energy is taken as X, namely Xi, Xi-e, Xi+e, Xi+2e, Xi-2e, Xi+3e, Xi-3e.

5. According to claim 1, a method for decomposing electric power within a preset time period taking into account the uncertainty of new energy sources, characterized in that: The step F includes: according to the calculated medium- and long-term decomposition sequence G, i.e., G0, G1, G2, G3, G4, G5, G6, averaging the above decomposition sequence according to the corresponding time period, and calculating the power decomposition curve of the generator set under the uncertainty sequence of new energy power generation.

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