A power grid peak shaving method and system based on wind-solar-hydro-thermal multi-energy complementary characteristics

Abstract

The application discloses a kind of based on the characteristics of wind, light, water and fire multi-energy complementary characteristics power grid peak shaving method and system, comprising: form the tie line power transmission plan considering new energy complementary output characteristics, season and daily load variation, to cooperate with power grid peak shaving;Prior to use the water turbine unit with regulating capacity to participate in peak shaving;If not meet the requirement of peak shaving, call pumped storage power station to cut peak and fill valley;If it cannot meet the requirement of peak shaving, then implement orderly power utilization;Coal-fired unit is started and stopped to cope with peak shaving demand;Finally, consider new energy power generation output control, limit the power generation output of new energy power station by peak shaving and power rejection;Comprehensively consider tie line power transmission and high-cost peak shaving resource to reform tie line power transmission plan;Establish the multi-objective joint coordination optimization model with the lowest total power generation cost of power system and the best energy-saving emission reduction effect as target;Solve the problem that existing technology cannot exert the peak shaving advantage of wind, light, water and fire multi-energy complementary characteristics.

Description

Technical Field

[0001] This invention belongs to the field of power grid peak shaving technology; in particular, it relates to a power grid peak shaving method and system based on the complementary characteristics of wind, solar, hydro and thermal energy. Background Technology

[0002] Against the backdrop of the "dual carbon" goal, my country's new energy industry has continuously grown and expanded in recent years, with its industrial scale and technological equipment levels reaching new heights, making outstanding contributions to alleviating energy resource constraints and ecological environmental pressures. However, at the same time, the contradiction of unbalanced and insufficient development of new energy has become increasingly prominent, particularly the issue of new energy consumption, which has seriously constrained the healthy and sustainable development of the new energy industry. During this crucial strategic opportunity period of my country's energy transition, focusing on building a clean, low-carbon, safe, and efficient energy system, improving the level of clean energy utilization and the operational efficiency of the power system, implementing the new development philosophy, and better leveraging the role of multi-energy complementarity in energy security have become key areas of research in new energy.

[0003] Electricity cannot be stored in large quantities; its generation and consumption are synchronized. Therefore, the amount of electricity needed must be matched by the amount generated. The load on the power system frequently changes. To maintain power balance and system frequency stability, power generation must adjust generator output accordingly—this is called peak shaving. Currently, the large-scale integration of new energy sources into the grid has placed significant pressure on peak shaving. Thermal power plants frequently need to participate in deep peak shaving to ensure the safe operation of the grid, leading to a sharp increase in peak shaving pressure, reduced equipment lifespan, and poor economic efficiency. Current research on peak shaving strategies largely focuses on configuring energy storage systems and constructing multi-objective models for optimization calculations. The former has high peak shaving costs, and research on hybrid energy storage system peak shaving technology is still immature, with problems such as inaccurate modeling and imperfect operational strategies. The latter is computationally complex, difficult to promote, and fails to leverage the peak shaving advantages of the complementary characteristics of wind, solar, hydro, and thermal energy. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a power grid peak shaving method and system based on the complementary characteristics of wind, solar, hydro and thermal energy, so as to solve the problems of high peak shaving cost based on energy storage system configuration, immature research on hybrid energy storage system peak shaving technology, inability to accurately model and imperfect operation strategy, and complex calculation of peak shaving strategy for constructing multi-objective model for optimization calculation, which is difficult to promote and cannot give full play to the peak shaving advantages of wind, solar, hydro and thermal energy complementarity.

[0005] Technical solution of the present invention:

[0006] A power grid peak-shaving method based on the complementary characteristics of wind, solar, hydro, and thermal energy, the method comprising:

[0007] Step 1: Develop a tie-line transmission power plan that takes into account the complementary output characteristics of new energy sources, seasonal and daily load changes, in order to cooperate with grid peak shaving;

[0008] Step 2: During peak shaving, priority should be given to using hydropower units with regulating capabilities to participate in peak shaving;

[0009] Step 3: Utilize thermal power units for peak shaving;

[0010] Step 4: If the peak shaving capacity of thermal power is insufficient to meet the peak shaving requirements, pumped storage power stations shall be used to reduce peak loads and fill valleys, while ensuring the reserve level.

[0011] If steps 5 and 1-4 cannot meet the peak-shaving requirements, then consider load demand-side management and implement orderly electricity use.

[0012] Step 6: Start and stop coal-fired power units to meet peak demand;

[0013] Step 7: Finally, consider the control of renewable energy power generation output. When the peak-shaving capacity of the system's conventional power supply and energy storage equipment is insufficient to enable the system to fully accept the renewable energy power generation output with strong volatility and anti-peak-shaving characteristics, limit the power generation output of renewable energy power plants through peak-shaving and curtailment.

[0014] Step 8: Taking into account the technical and economic feasibility of tie-line power transmission and high-cost peak-shaving resources, revise the tie-line power transmission plan;

[0015] Step 9: On the basis of prioritizing the consumption of renewable energy, establish a multi-objective joint coordination optimization model with the goal of minimizing the total power generation cost of the power system and achieving the best energy conservation and emission reduction effect.

[0016] When coordinating with grid peak shaving, the power transmission plan of tie lines should take into account the complementary output characteristics of new energy sources, seasonal and daily load changes, and prioritize the generation of new energy units such as wind power and photovoltaic power. This is conducive to the absorption of new energy sources, thereby maximizing the energy conservation and emission reduction effect of the power system and reducing the generation cost.

[0017] The method of prioritizing the use of hydropower units with regulation capabilities during peak shaving is as follows: on the one hand, leveraging the power generation efficiency and peak shaving capacity of hydropower stations to compensate for the impact of wind power and solar energy power generation output; on the other hand, utilizing the capacity efficiency of hydropower stations to reduce the operating capacity of thermal power units, improve the technical and economic efficiency of thermal power unit operation, thereby reducing the system's installed capacity, reducing investment in system power source construction, and lowering the peak shaving cost of the power system.

[0018] The method of utilizing thermal power units to participate in peak shaving is as follows: utilizing deep peak shaving resources, during the call-up process, small-capacity thermal power units that do not bear the base load are given priority to participate in peak shaving, and then available large-capacity units are called up.

[0019] The objective function of the multi-objective joint coordination optimization model is expressed as:

[0020] minF(P)=minE WQ

[0021]

[0022]

[0023] ∩max{min(ΔP sm (n Mm ),m=1,2,...,12)}

[0024] ∩min{F(P T )|max(min(ΔP sm ,m=1,2,...,12))∩min(ΔE s )}

[0025] In the formula, ∩ represents a parallel relationship; F(P) and F(P) T The figures are the total annual power generation cost of the power system and thermal power plants (or primary energy consumption; pollutant emissions; grid thermal power purchase cost), respectively; P, P T These represent the annual power generation output of the power plant and the thermal power plant, respectively; ΔE s ΔP sm These represent the system or partition's annual power shortage (s) and monthly power surplus (m), respectively; n Mm The number of generating units scheduled for maintenance in month m of the year; E WQ E HQ These are respectively the amount of abandoned renewable energy and the amount of abandoned hydropower; E Q =E WQ +E HQ This represents the sum of the amount of renewable energy and hydropower abandoned by the power system in a given year. These represent the maximum power generation output of hydropower and pumped storage power stations in the current year and month (m), respectively; R Hm R Pm The standby capacity for hydropower and pumped storage in the horizontal year m month is respectively; T E This represents the expected annual power generation utilization hours of the power plant.

[0026] The beneficial effects of this invention are:

[0027] This invention provides a multi-energy complementary integrated system, including two modes: wind-solar-hydro complementary integration and wind-solar-thermal complementary integration. This allows for research into various multi-energy complementary integrated scenarios, enabling coordinated and optimized scheduling and intensive management of multiple energy sources. Power electronics facilitate grid connection of the multi-energy complementary integrated power source, while isolation transformers ensure electrical isolation between the power source and the grid, guaranteeing the safety of grid connection. Users, the multi-energy complementary integrated system, and peak-shaving strategies are connected to a monitoring and dispatch center. This center can monitor the entire line, ensuring transmission stability, preventing accidents, and implementing timely detection measures, thus achieving "sustainable" control over the entire system. "Observable, measurable, adjustable, and controllable," the monitoring and dispatch center is connected to the peak-shaving strategy. The connection sequence of the peak-shaving strategy is set, and the peak-shaving purpose is achieved through the orderly combination of different peak-shaving methods. This invention uses the monitoring and dispatch center to detect changes in load demand and the output of the multi-energy complementary integrated power source in real time. The detected data is compared, and corresponding peak-shaving strategies are adopted, resulting in lower peak-shaving costs. It fully leverages the peak-shaving advantages of the multi-energy complementary characteristics of wind, solar, hydro, and thermal power to achieve the peak-shaving purpose, ensuring the stability of the multi-energy complementary integrated system. This optimizes wind power, photovoltaic new energy power generation, and traditional energy power generation (hydropower, thermal power), increases the absorption of new energy, reduces the amount of new energy wasted, increases the amount of new energy generated, and reduces carbon emissions.

[0028] This addresses the problems of high peak-shaving costs associated with configuration-based energy storage systems, the immaturity of research on peak-shaving technology for hybrid energy storage systems, the inability to accurately model and the imperfect operation strategies, as well as the complexity of calculating peak-shaving strategies for constructing multi-objective models for optimization, making them difficult to promote and unable to leverage the peak-shaving advantages of the complementary characteristics of wind, solar, hydro, and thermal energy. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the system composition of the present invention;

[0030] Figure 2 This is a schematic diagram of the peak shaving process of the present invention. Detailed Implementation

[0031] A power grid peak-shaving method and system based on the complementary characteristics of wind, solar, hydro, and thermal energy includes:

[0032] The peak-shaving system of this invention includes:

[0033] Multi-energy complementary integration can be configured in two modes: wind-solar-hydro complementary integration and wind-solar-thermal complementary integration. As the power source of the peak-shaving system, it can provide a variety of multi-energy complementary integration scenario studies, realize the coordinated optimization scheduling and intensive management of multiple energy sources. Multi-energy complementary integration is connected to power electronics, including frequency converters and inverters, which can adjust the voltage and frequency of the multi-energy complementary integrated power source to the AC voltage and frequency required for grid connection, so as to realize the safe grid connection of the multi-energy complementary integrated power source.

[0034] Power electronics are connected to an isolation transformer, which in turn is connected to the power grid. This enables multi-energy complementary integrated power sources to be connected to the power grid and provides electrical isolation between the multi-energy complementary integrated power source and the power grid, ensuring the safety of the multi-energy complementary integrated power source connected to the power grid.

[0035] The power grid is connected to the users, and the power grid connected to the users is the distribution network. This enables multi-energy complementary integrated power sources to supply power to users, which is conducive to the consumption of new energy sources. Users are connected to the monitoring center, which is simultaneously connected to the multi-energy complementary integrated power generation and peak-shaving strategies. The monitoring center realizes the "observability, measurability, adjustability, and controllability" of the entire power system. It can monitor the entire line to ensure the stability of line transmission, prevent accidents, and monitor the electricity consumption of users and the power generation of multi-energy complementary integrated power units in real time. By connecting to the peak-shaving strategy, it achieves the supply and demand balance of electricity consumption and power generation, thus achieving the purpose of peak shaving.

[0036] Peak-shaving method of the present invention:

[0037] This invention addresses the current state of power grid peak shaving and the problems of increased reserve demand, increased peak shaving pressure, and high peak shaving costs caused by the large-scale integration of renewable energy. Considering the technical and economic feasibility of various peak shaving methods, the peak shaving methods applicable to the power grid after the integration of large-capacity renewable energy include:

[0038] (1) Formulate a tie-line power transmission plan that considers the complementary output characteristics of new energy sources, seasonal and daily load changes, in order to cooperate with grid peak shaving. New energy generators have advantages such as being clean, low-carbon, renewable, and having low power generation costs. However, wind and solar generators have disadvantages such as randomness, fluctuation, regionality, lack of bidirectional peak shaving capability, and low dispatchability, which have a significant impact on the power generation scheduling of other generators in the system. Formulating a tie-line power transmission plan that considers the complementary output characteristics of new energy sources, seasonal and daily load changes, and prioritizing the power generation of new energy units such as wind and solar power, is conducive to the absorption of new energy sources, thereby maximizing the energy conservation and emission reduction effect of the power system and reducing power generation costs.

[0039] (2) Prioritize the use of hydropower units with regulating capabilities during peak shaving. Hydropower units also have advantages such as being clean, low-carbon, renewable, and having low power generation costs. At the same time, hydropower stations with regulating reservoir capacity have good dispatchability, hardly cause additional losses when undertaking variable loads, and have a fast response speed. Therefore, under the premise of ensuring full utilization of their limited energy resources, hydropower stations should be arranged to operate at the peak position of the daily load of the system or region as much as possible to give full play to their good regulating performance and low cost. On the one hand, the power generation benefits and peak shaving capabilities of hydropower stations can be fully utilized to compensate for the impact of the randomness and low dispatchability of power generation output of new energy units such as wind power and solar power, improve the operating conditions of thermal power units in the power system, and improve the technical and economic efficiency of thermal power unit operation; on the other hand, the capacity benefits of hydropower stations can be fully utilized to reduce the operating capacity of thermal power units, further improve the technical and economic efficiency of thermal power unit operation, and thus reduce the system's installed capacity, reduce the investment in system power construction, and reduce the peak shaving cost of the power system.

[0040] (3) Reusing thermal power units for peak shaving. Utilizing deep peak shaving resources, small-capacity thermal power units that do not bear base load are prioritized for peak shaving during the call-up process, followed by available large-capacity units. Thermal power units have certain regulation capabilities and load response speeds, high fuel supply security, and strong continuous power generation capabilities, playing a crucial role in power system peak shaving. Calling up thermal power units for peak shaving can quickly respond to load changes, ensuring the safe and stable operation of the power system.

[0041] (4) If the peak shaving capacity of thermal power is insufficient to meet the peak shaving requirements, pumped storage power stations shall be used for peak shaving and valley filling while ensuring the reserve level. Pumped storage units have the same superior operating characteristics as conventional hydropower units: rapid start-up and load-bearing, long service life, low operation and maintenance costs, low accident rate, and double the peak shaving capacity benefits. Its peak shaving advantages are reflected in: first, transferring the surplus power during the low load period of the system to the peak load period, thereby improving the operating conditions of other power sources (such as thermal power) in the system, improving their equipment utilization rate and the overall technical and economic efficiency of the system operation; second, it can serve as a low-cost, rapid-response emergency backup power source to undertake the system's frequency regulation, phase regulation, and black start tasks.

[0042] (5) If the first four measures still cannot meet the peak-shaving requirements, then demand-side management should be considered to implement orderly electricity consumption. Joint management of the electricity market by both the supply and demand sides is conducive to improving the reliability of power supply and reducing energy consumption and costs for both the supply and demand sides, thereby achieving the goal of energy conservation and emission reduction.

[0043] (6) Furthermore, the operation and shutdown of coal-fired power units should be considered to meet peak demand. This is conducive to ensuring the safe and stable operation of the power system.

[0044] (7) Finally, consider the control of renewable energy power generation output, that is, consider renewable energy curtailment. When the peak-shaving capacity of the system's conventional power sources and energy storage devices is insufficient to enable the system to fully accept the renewable energy power generation output with strong volatility and anti-peak-shaving characteristics, the power generation output of renewable energy power plants is limited by peak-shaving curtailment, thereby ensuring the system's peak-shaving balance and safe and stable operation.

[0045] (8) If the current peak-shaving strategy has overused high-cost peak-shaving resources, the technical and economic feasibility of tie-line power transmission and high-cost peak-shaving resources should be comprehensively considered, and the tie-line power transmission plan should be revised.

[0046] (9) Establish a simulation model for the operation of a multi-energy-access power system. Starting from the overall power system and its actual conditions, fully consider the characteristics of various power plants (including wind power, hydropower, thermal power, pumped storage, and peak-shaving power plants), and make full use of green, low-carbon, and renewable energy resources such as hydropower, wind power, and photovoltaic power generation in the system. Simulate the power system's generation dispatching methods for the maximum load day of each month and the typical week of each hour throughout the year to verify whether the system's installed capacity meets the system load demand, determine the optimal operating position and capacity of each power plant on the system's daily load curve, and evaluate the status and role of each power plant in the system. Based on prioritizing the consumption of renewable energy, a multi-objective joint coordination optimization model is established with the goal of minimizing the total power generation cost and achieving the best energy conservation and emission reduction effect. Its objective function can be expressed as:

[0047] minF(P)=minE WQ

[0048]

[0049]

[0050] ∩max{min(ΔP sm (n Mm ),m=1,2,...,12)}

[0051] ∩min{F(P T )|max(min(ΔP sm ,m=1,2,...,12))∩min(ΔE s )}

[0052] In the formula, ∩ represents a parallel relationship; F(P) and F(P) T The figures are the total annual power generation cost of the power system and thermal power plants (or primary energy consumption; pollutant emissions; grid thermal power purchase cost), respectively; P, P T These represent the annual power generation output of the power plant and the thermal power plant, respectively; ΔE s ΔP smThese represent the system or partition's annual power shortage (s) and monthly power surplus (m), respectively; n Mm The number of generating units scheduled for maintenance in month m of the year; E WQ E HQ These are respectively the amount of abandoned renewable energy and the amount of abandoned hydropower; E Q =E WQ +E HQ This represents the sum of the amount of renewable energy and hydropower abandoned by the power system in a given year. These represent the maximum power generation output of hydropower and pumped storage power stations in the current year and month (m), respectively; R Hm R Pm The standby capacity for hydropower and pumped storage in the horizontal year m month is respectively; T E This represents the expected annual power generation utilization hours of the power plant.

[0053] This invention monitors the electricity consumption on the demand side and the power generation of multi-energy complementary integrated power units in real time through a monitoring and dispatch center. By comparing the detected electricity consumption and power generation data, and considering the technical and economic advantages of various peak-shaving methods, prioritizing renewable energy consumption, minimizing the total power generation cost, and maximizing energy conservation and emission reduction, the invention adopts a corresponding priority order for peak-shaving methods to keep costs low. The multi-objective joint coordination optimization simulation model established by this invention is simple and can be extended to scenarios involving multiple energy sources such as nuclear and biomass energy. This invention fully leverages the peak-shaving advantages of the complementary characteristics of wind, solar, hydro, and thermal power to achieve peak-shaving objectives, ensuring the stability of the multi-energy complementary integrated system. This achieves the goal of optimizing the coordinated output of wind power, photovoltaic power, and other new energy generation with traditional energy generation such as hydropower and thermal power, increasing the consumption of new energy, reducing the amount of new energy wasted, increasing the amount of new energy generated, and reducing carbon emissions.

Claims

1. A power grid peak-shaving method based on the complementary characteristics of wind, solar, hydro, and thermal energy, characterized in that: The method includes: Step 1: Develop a tie-line transmission power plan that takes into account the complementary output characteristics of new energy sources, seasonal and daily load changes, in order to cooperate with grid peak shaving; Step 2: During peak shaving, priority should be given to using hydropower units with regulating capabilities to participate in peak shaving; Step 3: Utilize thermal power units for peak shaving; Step 4: If the peak shaving of thermal power plants cannot meet the peak shaving requirements, pumped storage power plants shall be used to reduce peak loads and fill valleys while ensuring the reserve level. If steps 5 and 1-4 cannot meet the peak-shaving requirements, then consider load demand-side management and implement orderly electricity use. Step 6: Start and stop coal-fired power units to meet peak demand; Step 7: Finally, consider the control of renewable energy power generation output. When the peak-shaving capacity of the system's conventional power supply and energy storage equipment is insufficient to enable the system to fully accept the renewable energy power generation output with strong volatility and anti-peak-shaving characteristics, limit the power generation output of renewable energy power plants through peak-shaving and curtailment. Step 8: Taking into account the technical and economic feasibility of tie-line power transmission and high-cost peak-shaving resources, revise the tie-line power transmission plan; Step 9: On the basis of prioritizing the consumption of renewable energy, establish a multi-objective joint coordination optimization model with the goal of minimizing the total power generation cost of the power system and achieving the best energy conservation and emission reduction effect; The objective function of the multi-objective joint coordination optimization model is expressed as: ； In the formula, Indicates a parallel relationship; , These represent the total power generation costs of the power system and thermal power plants in the horizontal year, respectively. , These refer to the annual power generation output of the power plant and the thermal power plant, respectively. , Respectively, system or partition Insufficient annual power supply and Monthly electricity surplus; For horizontal years Number of units scheduled for maintenance each month; , These are respectively the amount of abandoned electricity from new energy sources and the amount of abandoned water from hydropower. This represents the sum of the amount of renewable energy and hydropower abandoned by the power system in a given year. , Horizontal years respectively Maximum power generation capacity of monthly hydropower and pumped storage power stations; , Horizontal years respectively Monthly hydropower and pumped storage provide backup capacity; This represents the expected annual power generation utilization hours of the power plant.

2. The power grid peak-shaving method based on the complementary characteristics of wind, solar, hydro, and thermal energy as described in claim 1, characterized in that: When coordinating with grid peak shaving, the power transmission plan of tie lines should take into account the complementary output characteristics of new energy sources and seasonal and daily load changes. Priority should be given to wind power and photovoltaic power generation, which is conducive to the absorption of new energy sources, thereby maximizing the energy conservation and emission reduction effect of the power system and reducing power generation costs.

3. A power grid peak-shaving method based on the complementary characteristics of wind, solar, hydro, and thermal energy as described in claim 1, characterized in that: The method of prioritizing the use of hydropower units with regulation capabilities during peak shaving is as follows: on the one hand, leveraging the power generation efficiency and peak shaving capacity of hydropower stations to compensate for the impact of wind power and solar energy power generation output; on the other hand, utilizing the capacity efficiency of hydropower stations to reduce the operating capacity of thermal power units, improve the technical and economic efficiency of thermal power unit operation, thereby reducing the system's installed capacity, reducing investment in system power source construction, and lowering the peak shaving cost of the power system.

4. A power grid peak-shaving method based on the complementary characteristics of wind, solar, hydro, and thermal energy as described in claim 1, characterized in that: The method of utilizing thermal power units to participate in peak shaving is as follows: utilizing deep peak shaving resources, during the call-up process, small-capacity thermal power units that do not bear the base load are given priority to participate in peak shaving, and then available large-capacity units are called up.

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