Method for estimating the scale of medium- and long-term electricity market transactions

Abstract

The present invention discloses a method for calculating the transaction scale of the medium- and long-term electricity market. Under the premise of ensuring the balance of electric power, the method is based on the two-way matching of the user side and the power supply side in the medium- and long-term electricity market, combined with the current situation and planning of market users and market units. This method overcomes the defect of existing analysis methods that mainly rely on subjective estimates of experts. It reasonably calculates the market space on the power supply side and the transaction demand on the user side, and determines them through two-way matching and fitting verification. It ensures the orderly and accurate execution of the measurement work from the aspects of systematicity, standardization and objectivity. The present invention has been applied to the implementation plan of the provincial power market, providing scientific guidance and support for the formulation of power market planning and the operation and supervision of the power market.

Description

Technical Field

[0001] The present invention belongs to the technical field of power transaction analysis, and in particular relates to a method for estimating the transaction scale of a medium- and long-term power market. Background Art

[0002] Currently, most provinces across China have entered the medium- and long-term electricity market trading phase, with some provinces implementing both medium- and long-term and spot trading. Market demand is steadily expanding, and planning market transactions in advance is crucial. Considering the actual situation of electricity trading, estimating the scale of medium- and long-term electricity market transactions for the next year is a key prerequisite for conducting the next year's transactions. However, current analysis and estimation methods rely primarily on subjective estimates by experts in the power market, lacking a systematic and standardized approach. Their accuracy is questionable, making it difficult to meet the requirements for estimating the scale of medium- and long-term electricity market transactions in the new era. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method for calculating the transaction scale of the medium and long-term electricity market, which ensures the orderly and accurate progress of the calculation work from the aspects of systematicity, standardization and objectivity.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] The method for calculating the transaction scale of the medium- and long-term electricity market is based on the two-way matching between the user side and the power supply side in the medium- and long-term electricity market, taking into account the current situation and planning of market users and market units, while ensuring the balance of electric power.

[0006] The above-mentioned method for calculating the scale of medium- and long-term electricity market transactions includes the following steps:

[0007] Step 1: Based on the daily load curve of the power grid and the unit parameters and output characteristics of wind power, photovoltaic power, thermal power, gas power, hydropower, and nuclear power, a multi-type power dispatch model is established to minimize the dispatching and operating costs of multiple power sources. The output and power generation of each type of power source are calculated, and the balanced utilization hours of each type of power source are determined;

[0008] Step 2: Determine the market power source type for the forecast year based on the market unit situation and construction plan of the province where the power market is located;

[0009] Step 3: Calculate the market electricity scale of each type of market power supply;

[0010] Step 4: Calculate the market space on the power supply side; cumulatively sum the market electricity of each type of market power supply calculated in step 3;

[0011] Step 5: Calculate transaction demand on the user side;

[0012] Step 6: Bidirectional matching between the power supply side and the user side. The smaller value of the power supply side market space in step 4 and the user side transaction demand in step 5 is taken as the preliminary space for medium- and long-term power market transactions.

[0013] Step 7: Verify the market-based electricity quantity.

[0014] In the fifth step: Taking into account the distribution of large users in the market and the large proportion of industrial electricity in the market, considering that the user side is mainly industrial users, industrial users are divided into conventional industrial users and large industrial users; among them, the market demand of conventional industrial users is determined by their historical electricity demand multiplied by the growth rate, and the market demand of large industrial users is determined by the sum of their historical electricity demand and the new electricity demand brought about by future production expansion.

[0015] The seventh step is to proceed as follows: Usually, the change of market size conforms to the change law of the growth curve described by the logistics function. The least squares method is used to fit the logistic fitting function of the marketization rate of the historical and predicted years. The marketization rate of the predicted year is corrected in combination with the curve, and the market electricity is rounded to obtain the final medium- and long-term electricity market transaction scale.

[0016] The third step includes:

[0017] Calculate the market electricity scale of thermal power; the market electricity scale of thermal power is the thermal power generation minus the thermal power generation to ensure heat supply and safety; consider that there is a large gap between the actual utilization fraction of thermal power in historical years and the utilization hours of thermal power in the power balance in the next few years. At the same time, relevant national documents clearly state that the positioning of thermal power in the future will shift from the main power source to the regulating power source. Therefore, there is a certain uncertainty in the utilization hours of thermal power. It is necessary to conduct a sensitivity analysis on the utilization hours of thermal power and set three scenarios: high, medium and low. Then, the thermal power generation is obtained by multiplying the utilization hours of thermal power and the installed capacity. Among them, the thermal power utilization hours of the high scenario take the maximum value of the thermal power utilization hours in the historical years and the thermal power utilization hours in the annual balance of the whole region during the forecast period; the medium scenario takes the average of the thermal power utilization hours in the historical years and the thermal power utilization hours in the annual balance of the whole region during the forecast period; the low scenario takes the minimum value of the thermal power utilization hours in the historical years and the thermal power utilization hours in the annual balance of the whole region during the forecast period; the electricity for ensuring heat supply and safety is determined by multiplying the proportion of the installed capacity for ensuring heat supply and safety in the whole region by the annual thermal power generation.

[0018] Calculate the market size of nuclear power; based on the operational characteristics of nuclear power in the power system and its marketization, nuclear power generation is all medium- and long-term trading market electricity;

[0019] Calculate the market electricity scale of wind power; wind power output has significant uncertainty, and the wind power market electricity is calculated by multiplying the wind power generation capacity by the confidence level coefficient of wind power output. The confidence level coefficient of wind power output is determined according to the historical wind power output characteristics; to enhance the inclusiveness of the forecast, the wind power output coefficients of the high scenario, medium scenario, and low scenario are respectively taken as the output coefficients corresponding to the wind power output guarantee rate of 97%, 95%, and 90% in a statistical sense.

[0020] In the first step: the establishment of a multi-type power dispatch model includes objective functions and constraints; the objective function is to minimize the dispatching and operating costs of multi-type power sources; the constraints include power balance constraints, full absorption constraints of wind power, photovoltaic power and nuclear power, thermal power unit output constraints, gas power output constraints, hydropower output constraints, etc.

[0021] The objective function satisfies the following formula:

[0022]

[0023] Where: N wind 、N pv 、N thermal 、N gas 、N water 、N nuclear are the number of wind power, photovoltaic power, thermal power, gas power, hydropower, and nuclear power units respectively; i is the unit number; t is the hourly sequence number (1-8760 throughout the year); C wind,i 、C pv,i 、C thermal,i 、C gas,i 、C water,i 、C nuclear,i are the operating costs per kWh of unit i for wind power, photovoltaic power, thermal power, gas power, hydropower, and nuclear power respectively; P wind,i,t 、P pv,i,t 、P thermal,i,t 、P gas,i,t 、P water,i,t 、P nuclear,i,t are the dispatching outputs of unit i of wind power, photovoltaic power, thermal power, gas power, hydropower and nuclear power at time t respectively.

[0024] The constraints are:

[0025] 1) Power balance constraint, that is, the power output and load are equal at any time. The specific expression is as follows:

[0026]

[0027] Where, P load,t is the load at time t;

[0028] 2) Full consumption constraint of wind power, photovoltaic power, and nuclear power, that is, the dispatch output of wind power, photovoltaic power, and nuclear power at any time is consistent with the output determined by resource conditions. The specific expression is as follows:

[0029] P wind,i,t =P wind,actual,i,t 、P pv,i,t =P pv,actual,i,t 、P nuclear,i,t =P nuclear,actual,i,t

[0030] Where, P wind,actual,i 、P pv,actual,i 、P nuclear,actual,i are the outputs of unit i of wind power, photovoltaic power and nuclear power at time t determined by resource conditions;

[0031] 3) Thermal power unit output constraint, that is, the dispatch output of thermal power must be between the minimum technical output of the thermal power unit and the installed capacity. The specific expression is as follows:

[0032] P thermal,min,i ≤P thermal,i,t ≤S thermal,i

[0033] Where, P thermal,min,i 、S thermal,i are the minimum technical output and installed capacity of unit i of thermal power plant respectively;

[0034] 4) Hydropower output constraint: the hydropower dispatch output must not exceed the maximum output determined by water resources. The specific expression is as follows:

[0035] 0≤P water,i,t ≤P water,actual,i

[0036] Where, P water,actual,i The maximum output of hydropower unit i is determined by water resources.

[0037] 5) Gas-fired power output constraint: the dispatched output of gas-fired power must be between zero and the installed capacity of the gas-fired generator. The specific expression is as follows:

[0038] 0≤P gas,i,t ≤S gas,i

[0039] Where S gas,i The maximum output of gas-fired power unit I is determined by the scale of gas-fired power generation capacity.

[0040] In response to the current problems of lack of systematicity and standardization in power transaction analysis, the inventors have established a method for calculating the scale of medium- and long-term power market transactions. Under the premise of ensuring the balance of power and electricity, combined with the current status and planning of market users and market units, the method is based on the two-way matching of the user side and the power supply side in the medium- and long-term power market. This method overcomes the defect of existing analysis methods that mainly rely on subjective estimates of experts. It reasonably calculates the market space on the power supply side and the transaction demand on the user side, and determines the two-way matching and fitting verification, ensuring the orderly and accurate measurement work from the aspects of systematicity, standardization and objectivity. The present invention has been applied to the implementation plan of the provincial power market, providing scientific guidance and support for the formulation of power market planning and the operation and supervision of the power market. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a flow chart of the method for calculating the transaction scale of the medium and long-term electricity market of the present invention.

[0042] Figure 2 It is a rationality verification chart of the marketization rate. DETAILED DESCRIPTION

[0043] To further illustrate how the present invention is implemented, the medium- and long-term electricity market of Guangxi Zhuang Autonomous Region is taken as an actual sample, 2019 is taken as the base year, and the power installed capacity from 2020 to 2023 adopts the results of Guangxi's 14th Five-Year Power Planning. The transaction scale of the Guangxi medium- and long-term electricity market from 2021 to 2023 is calculated with reference to the above method.

[0044] Step 1: Conduct annual power balance for Guangxi from 2021 to 2023. The balance results are shown in Table 1:

[0045] Table 1 Electricity balance table for 2021-2023 (unit: billion kWh, hour)

[0046]

[0047]

[0048] Step 2: Based on the existing market unit situation and power market planning of the Guangxi power market, determine that the market power sources for 2021-2023 will be thermal power, nuclear power, and wind power.

[0049] Step 3: Calculate the market electricity scale of each type of market power supply.

[0050] The thermal power utilization hours in Guangxi in 2019 were 4295 hours. According to the results of the first step of balancing, the balanced thermal power utilization hours in 2021, 2022 and 2023 were 4793 hours, 4261 hours and 4043 hours respectively. Based on the above ideas, the market-oriented utilization hours of thermal power (without deducting the electricity for heat supply and safety) and the market electricity are determined as shown in Table 2.

[0051] Table 2 Market utilization hours of thermal power and market electricity consumption (unit: billion kWh, hour)

[0052]

[0053] According to the balancing results of the first step and the above ideas, the market electricity consumption of nuclear power is determined as shown in Table 3.

[0054] Table 3 Nuclear power market electricity (unit: billion kWh)

[0055] years High Plan Medium option Low plan 2021 152 152 152 2022 235 235 235 2023 317 317 317

[0056] The wind power market capacity is calculated by multiplying the available wind power generation by the confidence factor for wind power output, which is determined based on historical wind power output characteristics. The wind power output coefficients for the high, medium, and low scenarios are 0.0881, 0.1104, and 0.1418, respectively, corresponding to wind power output confidence levels of 97%, 95%, and 90%, respectively.

[0057] Table 4 Wind power market electricity (unit: billion kWh)

[0058] years Balanced power High Plan Medium option Low plan 2021 130 18 14 11 2022 160 23 18 14 2023 180 26 20 16

[0059] Step 4: Accumulate the market electricity volume of thermal power, nuclear power, and wind power (i.e., accumulate the results shown in Tables 2-4) and calculate the market space on the power supply side.

[0060] Table 5 Market space on the power supply side (unit: billion kWh)

[0061] years High Plan Medium option Low plan 2021 938 894 851 2022 1041 1033 1026 2023 1186 1155 1126

[0062] Step 5: Calculation of user-side transaction demand. The results are shown in Table 6.

[0063] Table 6 Calculation of user-side transaction demand (unit: 100 million kWh, 10,000 kW)

[0064]

[0065] Step 6: Match both the power supply side and the user side, take the smaller value in Table 5 and Table 6 and round them up, and the preliminary space for medium- and long-term electricity market transactions in 2021-2023 is 930, 1040, and 1190 TWh respectively.

[0066] Step 7: Market rate electricity verification. Figure 2 As shown, combined with the growth curve described by the logistics function, the least squares method is used to fit the history to correct the curve, and the medium and long-term electricity market transaction scale in 2021-2023 is 930, 1030, and 1150 billion kWh respectively.

Claims

1. A method for calculating the scale of medium- and long-term electricity market transactions, characterized by Under the premise of ensuring the balance of power, combined with the current situation and planning of market users and market units, the method is calculated based on the two-way matching between the user side and the power supply side in the medium and long-term power market. The specific steps include: Step 1: Based on the daily load curve of the power grid and the unit parameters and output characteristics of wind power, photovoltaic power, thermal power, gas power, hydropower, and nuclear power, a multi-type power dispatch model is established to minimize the dispatching and operating costs of multiple power sources. The output and power generation of each type of power source are calculated, and the balanced utilization hours of each type of power source are determined; Step 2: Determine the market power source type for the forecast year based on the market unit situation and construction plan of the province where the power market is located; Step 3: Calculate the market electricity scale of each type of market power supply; Step 4: Calculate the market space on the power supply side; cumulatively sum the market electricity of each type of market power supply calculated in step 3; Step 5: Calculate transaction demand on the user side; Step 6: Bidirectional matching between the power supply side and the user side. The smaller value of the power supply side market space in step 4 and the user side transaction demand in step 5 is taken as the preliminary space for medium- and long-term power market transactions. Step 7: Verify the market-based electricity quantity.

2. The method for calculating the scale of medium- and long-term power market transactions according to claim 1 is characterized in that In the fifth step: the user side is mainly industrial users, and industrial users are divided into conventional industrial users and large industrial users; among them, the market demand of conventional industrial users is determined by their historical electricity demand multiplied by the growth rate, and the market demand of large industrial users is determined by the sum of their historical electricity demand and the new electricity demand brought about by future production expansion.

3. The method for calculating the scale of medium- and long-term power market transactions according to claim 1 is characterized in that The seventh step is to perform the following operations: use the least squares method to fit the logistic fitting function of the marketization rate of the historical and predicted years, combine the curve to correct the marketization rate of the predicted year, and combine the market electricity volume to round up to obtain the final medium- and long-term electricity market transaction scale.

4. The method for calculating the scale of medium- and long-term power market transactions according to claim 1 is characterized in that The third step includes: Calculate the market electricity scale of thermal power; the market electricity scale of thermal power is the thermal power generation minus the electricity for heat supply and safety; conduct a sensitivity analysis on the thermal power utilization hours, and set three scenarios: high, medium, and low; then calculate the thermal power generation by multiplying the thermal power utilization hours by the installed capacity; among them, the thermal power utilization hours of the high scenario take the maximum value of the thermal power utilization hours in the historical years and the thermal power utilization hours in the annual regional balance during the forecast period; the medium scenario takes the average of the thermal power utilization hours in the historical years and the thermal power utilization hours in the annual regional balance during the forecast period; the low scenario takes the minimum value of the thermal power utilization hours in the historical years and the thermal power utilization hours in the annual regional balance during the forecast period; the electricity for heat supply and safety is determined by multiplying the proportion of the installed capacity for heat supply and safety in the total thermal power units in the region by the annual thermal power generation; Calculate the market size of nuclear power; based on the operational characteristics of nuclear power in the power system and its marketization, nuclear power generation is all medium- and long-term trading market electricity; Calculate the market electricity scale of wind power; calculate by multiplying the wind power generation capacity by the confidence level coefficient of wind power output, and the confidence level coefficient of wind power output is determined according to the historical wind power output characteristics; the wind power output coefficients of the high plan, medium plan and low plan are the output coefficients corresponding to the wind power output guarantee rate of 97%, 95% and 90% in a statistical sense respectively.

5. The method for calculating the scale of medium- and long-term power market transactions according to claim 1 is characterized in that In the first step: the establishment of the multi-type power supply scheduling model includes objective functions and constraints; the objective function is to minimize the scheduling and operation costs of multi-type power sources; the constraints include power balance constraints, full absorption constraints of wind power, photovoltaic power and nuclear power, thermal power unit output constraints, gas power output constraints, and hydropower output constraints.

6. The method for calculating the scale of medium- and long-term power market transactions according to claim 5 is characterized in that The objective function satisfies the following formula: Where: N wind 、N pv 、N thermal 、N gas 、N water 、N nuclear are the number of wind power, photovoltaic power, thermal power, gas power, hydropower, and nuclear power units respectively; i is the unit number; t is the hourly sequence number; C wind,i 、C pv,i 、C thermal,i 、C gas,i 、C water,i 、C nuclear,i are the operating costs per kWh of unit i for wind power, photovoltaic power, thermal power, gas power, hydropower, and nuclear power respectively; P wind,i,t 、P pv,i,t 、P thermal,i,t 、P gas,i,t 、P water,i,t 、P nuclear,i,t are the dispatching outputs of unit i of wind power, photovoltaic power, thermal power, gas power, hydropower and nuclear power at time t respectively.

7. The method for calculating the scale of medium- and long-term power market transactions according to claim 6 is characterized in that The constraints are: 1) Power balance constraint, that is, the power output and load are equal at any time. The specific expression is as follows: Where, P load,t is the load at time t, P wind,i,t 、P pv,i,t 、P thermal,i,t 、P gas,i,t 、P water,i,t 、P nuclear,i,t are the dispatch output of unit i of wind power, photovoltaic power, thermal power, gas power, hydropower, and nuclear power at time t; 2) Full consumption constraint of wind power, photovoltaic power, and nuclear power, that is, the dispatch output of wind power, photovoltaic power, and nuclear power at any time is consistent with the output determined by resource conditions. The specific expression is as follows: P wind,i,t =P wind,actual,i,t 、P pv,i,t =P pv,actual,i,t 、P nuclear,i,t =P nuclear,actual,i,t Where, P wind,actual,i 、P pv,actual,i 、P nuclear,actual,i are the outputs of unit i of wind power, photovoltaic power and nuclear power at time t determined by resource conditions; 3) Thermal power unit output constraint, that is, the dispatch output of thermal power must be between the minimum technical output of the thermal power unit and the installed capacity. The specific expression is as follows: P thermal,min,i ≤P thermal,i,t ≤S thermal,i Where, P thermal,min,i 、S thermal,i are the minimum technical output and installed capacity of unit i of thermal power plant respectively; 4) Hydropower output constraint: the hydropower dispatch output must not exceed the maximum output determined by water resources. The specific expression is as follows: 0≤P water,i,t ≤P water,actual,i Where, P water,actual,i The maximum output of hydropower unit i is determined by water resources; 5) Gas-fired power output constraint: the dispatched output of gas-fired power must be between zero and the installed capacity of the gas-fired generator. The specific expression is as follows: 0≤P gas,i,t ≤S gas,i Where S gas,i The maximum output of gas-fired power unit I is determined by the scale of gas-fired power generation capacity.

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