A long-term power and energy balance method in power system considering extreme weather

Abstract

The application discloses a kind of considering extreme weather in power system long-term power balance method, with the total cost of power system operation as objective function, establishes considering extreme weather long-term power balance model;Based on power system data, without considering the influence of extreme weather on the inflow of hydropower, solve the long-term power balance model considering extreme weather, obtain the operation index of power system under normal conditions;According to the operation index of power system under normal conditions and the solution of long-term power balance model considering extreme weather, obtain the operation index of power system when extreme weather occurs, according to the unit maintenance plan under normal conditions Organize the operation index of unit maintenance;By comparing two groups of operation indexes, adjust long-term operation decision of power system, realize power balance.The application can guarantee the economy and safety of power grid operation, optimize the long-term decision of generator unit maintenance plan, hydropower station power distribution and the like.

Description

Technical Field

[0001] This invention belongs to the field of long-term optimization operation in power systems, and relates to a long-term power balance method in power systems that takes into account extreme weather conditions. Background Technology

[0002] The balance of power supply and demand is crucial for the safe and stable operation of the power grid and represents a significant challenge for future power systems. Affected by global warming and the deteriorating natural environment, various extreme weather events have severely impacted the stable operation of the power system in recent years. Frequent extreme weather events such as droughts, floods, extreme heat, and extreme cold not only cause a surge in load in a short period but also increase the failure rate of power equipment on both the power generation and grid sides, adversely affecting the safe and stable operation of the power system.

[0003] With the proposal of the "dual carbon" target and the advancement of building a new power system dominated by new energy sources, the installed capacity of new energy sources such as wind and solar power is constantly increasing. In the future new power system, wind power and photovoltaic power should be included in the power balance. Due to the frequent occurrence of extreme weather, the volatility and uncertainty of power generation output from wind power, photovoltaic power, and hydropower in high-proportion new energy power systems have become prominent, posing a greater challenge to the grid balance.

[0004] Establishing a long-term power balance method for power systems that takes into account extreme weather is crucial for addressing the power balance problem between the power generation side and the load side, and is of great significance for further analysis of power system optimization operation.

[0005] Numerous scholars both domestically and internationally have studied the impact of extreme weather on power systems. Current research primarily focuses on improving power output models for new energy sources such as wind and solar power under extreme weather conditions, without considering the medium- to long-term seasonal characteristics of extreme weather. Research on the impact of extreme weather on hydropower inflow is also limited. Furthermore, the impact of extreme weather on the long-term power balance of power systems has been neglected, failing to meet future long-term power balance requirements.

[0006] In summary, the long-term power balance in the power system is a key aspect of optimizing power system operation. However, existing studies have failed to analyze the impact of extreme weather on hydropower inflow, nor have they further considered the impact of extreme weather on the power balance of the power system, making it impossible to accurately assess the long-term power balance capability of the power system under extreme weather conditions.

[0007] Existing studies on power grid balance do not consider the impact of extreme weather events. As a result, when extreme weather occurs, power supply is insufficient, which disrupts the power system's balance and affects the safe operation of the power grid and social production and life. Summary of the Invention

[0008] The purpose of this invention is to consider the impact of extreme weather on hydropower inflow and new energy output on a medium- to long-term timescale, and to establish a medium- to long-term power balance method for power systems that takes into account the impact of extreme weather. This method can obtain maintenance plans for various types of generator units and power system operation indicators within the power system, optimize medium- to long-term grid dispatch decisions, and improve the grid's ability to cope with extreme weather.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] A long-term power balance method for power systems that takes extreme weather into account includes the following steps:

[0011] Step 1: Obtain power system data;

[0012] Step 2: Using the total operating cost of the power system as the objective function, establish a medium- to long-term power balance model that takes extreme weather conditions into account;

[0013] Step 3: Based on the power system data obtained in Step 1, without considering the impact of extreme weather on hydropower inflow, solve the medium- and long-term power balance model that takes extreme weather into account, and obtain the operating indicators of the power system under normal conditions.

[0014] Step 4: Based on the operating indicators of the power system under normal conditions and the medium- and long-term power balance model considering extreme weather, the operating indicators of the power system when organizing unit maintenance according to the unit maintenance plan under normal conditions during extreme weather are obtained.

[0015] Based on the operational indicators in steps three and four, adjust the long-term operational decisions of the power system to achieve power balance.

[0016] Furthermore, the power system data includes the generation cost of thermal power units within the power system, the upper and lower limits of the output of thermal power, hydropower, pumped storage and wind power units, the upper and lower limits of hydropower generation, the maintenance requirements of thermal power, hydropower and pumped storage units, the upper and lower limits of DC power transmission and the amount of electricity transmitted, water curtailment, renewable energy curtailment, load shedding penalties, and approximate continuous load curves.

[0017] Furthermore, the operational constraints of hydropower units and the hydropower energy constraints of hydropower stations are as follows:

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[0027] In the formula, t represents the time period; b represents the segmentation of the approximate continuous load curve; hs represents the scenario; h represents the hydropower unit number; hp represents the hydropower station number; p hs h,t,b The power generation capacity of the hydroelectric generator unit; PDR hs h,t,b For downstream backup power that can be provided to hydroelectric generating units; pur hs h,t,b For upward backup power that can be provided by hydroelectric generating units; p hs h,t,min For the minimum technical output of the hydropower unit; p hs h,t,max To maximize the technical output of the hydropower units; hs h,t,b A 0-1 variable representing whether the hydropower unit is running; 1 if running, 0 otherwise; HP hs hp,t,min For forced output of hydroelectric power stations; HP hs hp,t,max To contribute to the anticipated development of the hydroelectric power station; HE hs hp,t The amount of electricity generated by the hydropower station during time period t; HE hs hp,t,min The lower limit of power generation of a hydropower station within time period t; HE hs hp,t,max The maximum power generation capacity of a hydroelectric power station within time period t; HC hs hp,t The amount of electricity wasted by a hydropower station during time period t; HE hs hp This represents the total annual electricity generated by the hydropower station.

[0028] Furthermore, the objective function is:

[0029]

[0030] Where: T is the total duration of the calculation cycle; B is the total number of segments of the approximate continuous load curve; g is the number of the thermal power unit; gp is the number of the thermal power plant; c g,t,b The pricing parameters for thermal power unit g during time period t; p g,t,b λ represents the unit's output during load segment b in time period t; Hλ is the penalty coefficient for wasted hydropower. R λ is the penalty coefficient for the amount of renewable energy wasted. L The penalty factor for the amount of power lost due to load change; RC t,b For the abandoned electricity of new energy sources; LC t,b D represents the amount of power lost due to load shedding. t,b Let be the duration of the b-th load level in the t-th time period.

[0031] Furthermore, the constraints of the medium- and long-term power balance model considering extreme weather conditions specifically include: maintenance and operation constraints of thermal power, hydropower, and pumped storage units, DC transmission constraints, and system operation constraints.

[0032] Furthermore, unit maintenance constraints include maintenance frequency, maintenance time, maintenance continuity, and power plant maintenance capacity constraints; unit operation constraints include the operating status and power range limits of thermal power, hydropower, pumped storage, and new energy; DC transmission constraints include upper and lower limits of DC transmission power and DC transmission amount constraints; system operation constraints include power balance constraints, energy balance constraints, and reserve constraints.

[0033] Furthermore, the operating indicators of the power system under normal conditions include the maintenance plans and total operating costs of thermal power, hydropower, and pumped storage units, thermal power fuel costs, power outages, renewable energy curtailment, and renewable energy curtailment rate.

[0034] Furthermore, the maintenance plans for thermal power, hydropower, and pumped storage units in the power system's operating indicators under normal conditions are incorporated into the solution of a medium- to long-term power balance model that considers extreme weather conditions.

[0035] Furthermore, the operating indicators for organizing unit maintenance according to the normal unit maintenance plan include the total system operating cost, thermal power fuel cost, power loss due to load, power curtailment of renewable energy, and renewable energy curtailment rate.

[0036] Compared with existing long-term power balance methods in power systems, the present invention has the following advantages:

[0037] This invention, based on the background of global warming and continuous deterioration of the natural environment, considers the impact of extreme weather on hydropower inflow over medium- to long-term timescales, quantifies the changes in hydropower inflow during extreme weather events, and proposes a medium- to long-term power balance method for power systems that takes extreme weather into account. This method can ensure the economic efficiency and safety of power grid operation, and optimize medium- to long-term decisions such as generator maintenance plans and hydropower station power allocation.

[0038] Furthermore, this invention can reflect the impact of extreme weather events such as continuous droughts and floods on hydropower inflow, and obtain indicators such as total system operating cost, thermal power fuel cost, power outage, renewable energy curtailment and renewable energy curtailment rate that reflect the long-term operation of the system. This enables the optimization of medium- and long-term decisions such as generator maintenance plans and hydropower station power allocation, promotes the coordination and complementarity of multiple types of generating units, and ensures the safe and stable operation of the power grid. Attached Figure Description

[0039] Figure 1 This is the overall process of the present invention. Detailed Implementation

[0040] The present invention will now be described in detail with reference to the accompanying drawings.

[0041] See Figure 1 This invention fully considers the impact of extreme weather on power system operation and proposes a long-term power balance method for power systems that takes extreme weather into account, including the following steps:

[0042] Step 1: Data Collection and Organization. Collect and organize data on the power generation costs of thermal power units, the upper and lower limits of output of thermal power, hydropower, pumped storage and wind power units, the upper and lower limits of power generation of hydropower stations, the maintenance requirements of thermal power, hydropower and pumped storage units, the upper and lower limits of DC power transmission and the amount of electricity transmitted, water curtailment, renewable energy curtailment, load shedding penalties, and approximate continuous load curves.

[0043] Step 2: Consider the impact of extreme weather on the inflow of water for hydropower, and construct operating constraints for hydropower units and hydropower station water energy constraints.

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[0053] In the formula, t represents the time period; b represents the segmentation of the approximate continuous load curve; hs represents the scenario; h represents the hydropower unit number; hp represents the hydropower station number; phs h,t,b The power generation capacity of the hydroelectric generator unit; PDR hs h,t,b For downstream backup power that can be provided to hydroelectric generating units; pur hs h,t,b For upward backup power that can be provided by hydroelectric generating units; p hs h,t,min For the minimum technical output of the hydropower unit; p hs h,t,max To maximize the technical output of the hydropower units; hs h,t,b A 0-1 variable representing whether the hydropower unit is running; 1 if running, 0 otherwise; HP hs hp,t,min For forced output of hydroelectric power stations; HP hs hp,t,max To contribute to the anticipated development of the hydroelectric power station; HE hs hp,t The amount of electricity generated by the hydropower station during time period t; HE hs hp,t,min The lower limit of power generation of a hydropower station within time period t; HE hs hp,t,max The maximum power generation capacity of a hydroelectric power station within time period t; HC hs hp,t The amount of electricity wasted by a hydropower station during time period t; HE hs hp This represents the total annual electricity generated by the hydropower station.

[0054] Step 3: Using the total operating cost of the power system as the objective function, and considering the maintenance and operation constraints of thermal power, hydropower, and pumped storage units, as well as the DC transmission constraints and system operation constraints, establish a medium- to long-term power balance model that takes extreme weather conditions into account.

[0055] The objective function can be expressed as:

[0056]

[0057] Where: T is the total duration of the calculation cycle; B is the total number of segments of the approximate continuous load curve; g is the number of the thermal power unit; gp is the number of the thermal power plant; c g,t,b The pricing parameters for thermal power unit g during time period t; p g,t,b λ represents the unit's output during load segment b in time period t; H λ is the penalty coefficient for wasted hydropower. R λ is the penalty coefficient for the amount of renewable energy curtailed (wind and solar power curtailment); L The penalty factor for the amount of power lost due to load change; RC t,b For the abandoned electricity of new energy sources; LC t,b D represents the amount of power lost due to load shedding. t,bLet be the duration of the b-th load level in the t-th time period.

[0058] The constraints of the medium- and long-term power balance model considering extreme weather conditions include: unit maintenance constraints, including constraints on maintenance frequency, maintenance time, maintenance continuity, and power plant maintenance capacity; unit operation constraints, including the operating status and power range limits of various types of units such as thermal power, hydropower, pumped storage, and new energy; DC transmission constraints, including upper and lower limits of DC transmission power and DC transmission amount constraints; and system operation constraints, including power balance constraints, energy balance constraints, and reserve constraints.

[0059] Step 4: Based on the data obtained in Step 1, without considering the impact of extreme weather on hydropower inflow, solve the medium- and long-term power balance model established in Step 3 that takes extreme weather into account. This will yield the power system's maintenance plans for thermal power, hydropower, and pumped storage units under normal conditions, as well as the total system operating cost, thermal power fuel cost, power outage, renewable energy curtailment, and renewable energy curtailment rate.

[0060] Step 5: Assume extreme weather conditions, such as a reduction in hydropower inflow to half of its original volume during the summer and autumn seasons. Substitute the maintenance plans for thermal power, hydropower, and pumped storage units under normal conditions obtained in Step 4 into a medium- to long-term power balance model that considers extreme weather conditions. This will yield the total system operating cost, thermal power fuel cost, power outage, renewable energy curtailment, and renewable energy curtailment rate when the power system continues to organize unit maintenance according to the normal maintenance plan during extreme weather events.

[0061] Based on the operational indicators in steps three and four, the long-term operational decisions of the power system are adjusted to achieve power balance. Specifically, by comparing the operational indicators in steps three and four, and considering the increase or decrease of indicators such as load shedding, renewable energy curtailment, and renewable energy curtailment rate under normal conditions and during extreme weather events, the proposed method's ability to cope with extreme weather and ensure power balance in the power system is obtained. Furthermore, it can comprehensively consider the economic efficiency and safety of system operation, and optimize long-term decisions such as generator maintenance plans and hydropower station power allocation.

[0062] The following example illustrates the implementation process of this method.

[0063] The example uses an adaptation of IEEE-RTS1979, with a study period of one year and weeks as the basic time unit. The system includes 26 thermal power units, 6 hydropower units, and 4 pumped storage units. Each unit undergoes maintenance for 3 or 4 consecutive weeks, and each power plant can only maintain a maximum of one unit at a time. The example data is shown in Table 1-3.

[0064] Table 1. Relevant data for thermal power units

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[0067] Table 2. Relevant data for hydropower units

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[0069] Table 3. Relevant data for pumped storage units

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[0071] The data from this example were input into the model established in this invention for calculation, and the maintenance plans for thermal power, hydropower and pumped storage units under normal conditions are shown in Tables 4-6, and the system operation indicators are shown in Table 7.

[0072] Table 4 Maintenance Plan for Thermal Power Units

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[0075] Table 5. Hydropower Unit Maintenance Plan

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[0077] Table 6 Maintenance Plan for Pumped Storage Units

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[0079] Table 7 System operating indicators under normal conditions

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[0082] By setting the extreme weather as extreme drought and considering that the water inflow to hydropower stations is reduced to half of the original amount during the summer and autumn seasons, the unit maintenance plans in Table 4-6 are substituted into the model for solution, and the various operating indicators of the system under extreme weather conditions are obtained as shown in Table 8.

[0083] Table 8 System Operation Indicators under Extreme Weather Conditions

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[0085] As shown in Tables 5 and 6, when extreme weather events such as drought occur, thermal power output increases and the capacity for renewable energy absorption is enhanced in order to ensure grid balance. This indicates that models that take extreme weather into account can effectively address the impact of extreme weather events on renewable energy output and hydropower inflow, thus ensuring the balance of power generation in the grid.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope disclosed in the present invention, based on the technical solutions and inventive concepts of the present invention, shall fall within the scope of protection of the present invention.

Claims

1. A long-term power balance method for a power system considering extreme weather conditions, characterized in that, Includes the following steps: Step 1: Obtain power system data; Step 2: Using the total operating cost of the power system as the objective function, establish a medium- to long-term power balance model that takes extreme weather conditions into account; Step 3: Based on the power system data obtained in Step 1, without considering the impact of extreme weather on hydropower inflow, solve the medium- and long-term power balance model considering extreme weather to obtain the operating indicators of the power system under normal conditions. The operating indicators of the power system under normal conditions include the maintenance plans of thermal power, hydropower, and pumped storage units. Step 4: Assume that extreme weather conditions reduce the water inflow of hydropower to half of the original amount during the summer and autumn seasons. Based on the maintenance plans of thermal power, hydropower, and pumped storage units under normal conditions obtained in Step 3, input them into the medium- and long-term power balance model that takes extreme weather conditions into account to obtain the operating indicators of the power system when extreme weather occurs and the unit maintenance is organized according to the normal unit maintenance plan. By comparing the operational indicators in steps three and four, and based on the increase or decrease in load loss, renewable energy curtailment, and renewable energy curtailment rate under normal conditions and during extreme weather events, the long-term operational decisions of the power system are adjusted to achieve power balance.

2. The long-term power balance method in a power system considering extreme weather conditions according to claim 1, characterized in that, Power system data includes the generation cost of thermal power units within the power system, the upper and lower limits of the output of thermal power, hydropower, pumped storage and wind power units, the upper and lower limits of hydropower generation, the maintenance requirements of thermal power, hydropower and pumped storage units, the upper and lower limits of DC power transmission and the amount of electricity transmitted, water curtailment, renewable energy curtailment, load shedding penalties, and approximate continuous load curves.

3. A long-term power balance method for a power system considering extreme weather conditions, as described in claim 1, is characterized in that... The operating constraints of hydropower units and the hydropower energy constraints of hydropower stations are as follows: （1） （2） （3） （4） （5） （6） （7） （8） （9） In the formula, t For a period of time; b This is a segmentation of the approximate continuous load curve; hs For the scene; h Number the hydroelectric generating units; hp A set of numbers for hydroelectric generating units; The generating capacity of the hydroelectric generator unit; This can provide downstream backup for hydroelectric generating units; This can provide upward backup for hydropower units; Minimum technical output for hydropower units; To maximize the technical capabilities of hydropower units; The variable is a 0-1 symbol representing whether the hydropower unit is running; it is 1 if the unit is running and 0 otherwise. Forced output for hydroelectric power stations; To contribute to the planned hydropower station; Hydropower station t Electricity generation during the period; Hydropower station t The lower limit of power generation during the time period; Hydropower station t Maximum power generation during a given period; Hydropower station t The amount of electricity wasted during the period; This represents the total annual electricity generated by the hydropower station. D t,b For the first t During the period b The duration of each load segment; B This represents the total number of segments in the approximate continuous load curve.

4. A long-term power balance method for a power system considering extreme weather conditions, as described in claim 1, is characterized in that... The objective function is: （10） In the formula: T This is the total duration of the calculation cycle; B This represents the approximate total number of segments in the sustained load curve; g Number the thermal power units; gp A set of unit numbers for thermal power units; c g,t,b For thermal power units g exist t Price parameters for different time periods; p g,t,b For the unit in t Time period b Output of the load section; λ H The penalty coefficient for wasted water volume; λ R The penalty coefficient for abandoned renewable energy power. λ L This is the penalty coefficient for the amount of power lost due to load imbalance; RC t,b For the abandoned electricity of new energy sources; LC t,b This refers to the amount of electricity lost due to load shedding; D t,b For the first t During the period b The duration of each load segment, For the hydroelectric power station t The amount of electricity wasted during the period hs For the scene; h Number the hydroelectric generator unit.

5. A long-term power balance method for a power system considering extreme weather conditions, as described in claim 1, is characterized in that... The constraints of the medium- and long-term power balance model considering extreme weather conditions specifically include: maintenance and operation constraints of thermal power, hydropower, and pumped storage units, DC transmission constraints, and system operation constraints.

6. A long-term power balance method for a power system considering extreme weather conditions, as described in claim 5, is characterized in that... Unit maintenance constraints include maintenance frequency, maintenance time, maintenance continuity, and power plant maintenance capacity constraints; unit operation constraints include the operating status and power range limits of thermal power, hydropower, pumped storage, and new energy; DC transmission constraints include upper and lower limits of DC transmission power and DC transmission amount constraints; system operation constraints include power balance constraints, energy balance constraints, and reserve constraints.

7. A long-term power balance method for a power system considering extreme weather conditions, as described in claim 1, is characterized in that... The operating indicators of the power system under normal conditions include the maintenance plans and total operating costs of thermal power, hydropower, and pumped storage units, thermal power fuel costs, power outages, renewable energy curtailment, and renewable energy curtailment rate.

8. A long-term power balance method for a power system considering extreme weather conditions, as described in claim 1, is characterized in that... Operating indicators for unit maintenance organized according to the normal unit maintenance plan include total system operating cost, thermal power fuel cost, power loss due to load, power curtailment of renewable energy, and renewable energy curtailment rate.

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