Source-storage collaborative planning method and system for new energy city power grid considering safety constraints

Abstract

A new energy city power grid source and storage collaborative planning method and system considering safety constraints, comprising: generating a typical scenario based on historical temperature data of the region where the new energy city power grid is located; based on the operating state and equivalent model of the pumped storage unit under different operating conditions, the short-circuit current provided by the pumped storage unit to the fault point under different operating conditions when a short-circuit fault occurs in the new energy city power grid is calculated; a new energy city power grid source and storage collaborative planning model containing each typical scenario is constructed, and a short-circuit ratio constraint of the grid connection point including the short-circuit capacity of the pumped storage unit is introduced into the model; the short-circuit capacity of the pumped storage unit is calculated based on the short-circuit current provided by the pumped storage unit to the short-circuit fault point under different operating conditions; the source and storage collaborative planning model is solved to obtain the output of each device in the new energy city power grid. The present application can solve the problem of the decrease of the equivalent short-circuit capacity of the system caused by the green transformation of the energy structure.

Description

Technical Field

[0001] This invention belongs to the field of power system planning, and in particular relates to a source-storage coordinated planning method and system for new energy urban power grids that takes into account safety constraints. Background Technology

[0002] As the load center of electricity, urban power grids are characterized by dense loads, high requirements for safety, reliability, and power quality. Urban power grid load demand is highly sensitive to temperature; worldwide, overload or heavy load events caused by heat waves or cold snaps, leading to system failures and power outages, occur frequently. Currently, the level of renewable energy generation in urban power grids is rapidly increasing; in the first three quarters of 2024, newly installed renewable energy capacity accounted for 86% of the total new installed capacity in China. The output capacity of renewable energy sources such as wind power, photovoltaics, and hydropower is also closely dependent on weather. Unfortunately, in most cases, the impact of temperature on load and renewable energy output is not consistent; sustained increases or decreases in temperature can worsen the system's ability to balance load demand, and even cause power outages. Furthermore, heat waves and cold snaps can also affect the stable operation of distribution channels; reverse fluctuations in source and load will lead to a continuous increase in line load rates and a surge in transmission pressure. Therefore, it is urgent to expand the power regulation capacity of urban power grids to cope with the severe challenges brought about by the rapid development of source and load.

[0003] Chinese patent application CN119543235A discloses a planning and scheduling method for pumped storage power stations, including: acquiring information on power generation equipment and electricity consumption types in the power grid, as well as historical power generation and consumption data of the power grid; predicting and generating trends in power generation and consumption of the power grid based on the historical power generation and consumption data; generating a planning and scheduling scheme for the pumped storage power station and performing operational scheduling. However, the following shortcomings still exist: this scheme focuses on trend prediction and economic scheduling based on historical data, failing to fully consider the weakening effect of high-proportion renewable energy access on the power system strength, and has limitations in addressing the risk of voltage instability at renewable energy grid connection points.

[0004] Chinese patent application CN118886549A discloses a configuration optimization method for pumped storage power stations. Based on parameters such as the number of pumped storage units participating in monthly, annual, and real-time power supply, as well as the power generation and pumping power of a single unit, a medium-to-long-term annual power supply revenue model and a real-time annual power supply revenue model are constructed, with the objective function aimed at maximizing the revenue of the pumped storage power station. The objective function is solved based on constraints such as reservoir capacity, risk conditions, and the number of pumped storage units, resulting in an optimized configuration scheme for the pumped storage power station. However, this method still has the following shortcomings: it does not incorporate source-load characteristics and equipment operation constraints under extreme weather scenarios into the optimization model, thus making it difficult to guarantee the grid resilience and power supply security of the planned scheme under extreme weather conditions.

[0005] In summary, new energy sources are gradually replacing traditional coal-fired and gas-fired power units. While this green transformation of the energy structure brings significant environmental benefits, it also presents new challenges to the safe and stable operation of the power system. Among these challenges, the reduction in the system's equivalent short-circuit capacity is a core and critical issue. Pumped storage units, like traditional synchronous machines, can provide strong inertial support and significant short-circuit current, directly and effectively improving the short-circuit capacity at the connection point. However, this characteristic has not yet been fully explored. Summary of the Invention

[0006] To address the problem of decreased system equivalent short-circuit capacity due to the green transformation of the energy structure in existing technologies, this invention provides a high-penetration new energy urban power grid source-storage coordinated planning method and system under the dual drive of short-circuit ratio and supply-demand security constraints.

[0007] The present invention adopts the following technical solution.

[0008] In a first aspect, the present invention discloses a method for coordinated planning of energy source and storage in urban power grids for new energy sources, taking into account safety constraints, comprising the following steps:

[0009] Based on historical temperature data of the area where the new energy urban power grid is located, typical scenarios are generated; the typical scenarios include heat wave scenarios, cold wave scenarios, and normal scenarios; the new energy urban power grid includes pumped storage units.

[0010] Based on the operating status and equivalent model of pumped storage units under different operating conditions, the short-circuit current provided by pumped storage units to the short-circuit fault point under different operating conditions is calculated when a short-circuit fault occurs in the new energy urban power grid.

[0011] A new energy urban power grid source-storage coordinated planning model is constructed, which includes various typical scenarios. The model introduces grid connection point short-circuit ratio constraints, including the short-circuit capacity of pumped storage units. The short-circuit capacity of pumped storage units is calculated based on the short-circuit current provided by pumped storage units to the short-circuit fault point under different operating conditions.

[0012] The source-storage collaborative planning model is solved to obtain the power output of each device in the new energy urban power grid under various typical scenarios.

[0013] More preferably,

[0014] The heat wave scenario is a set of power curves for renewable energy output and load demand on heat wave days; the cold wave scenario is a set of power curves for renewable energy output and load demand on cold wave days; the normal scenario is a set of power curves for renewable energy output and load demand on neither heat wave nor cold wave days.

[0015] More preferably,

[0016] The heatwave day is based on the heatwave day judgment index. Confirmed, the heatwave day judgment index Specifically:

[0017]

[0018] in, It is a step function; For the temperature data sequence, the first The highest temperature of the day; The 95th percentile of the highest historical temperature in the area where the new energy city power grid is located; d For day ordinal numbers, when At that time, the first d The day was a heatwave day;

[0019] The cold wave day is based on the cold wave day judgment index. Confirmed, the cold wave day judgment index Specifically:

[0020]

[0021] in, It is a step function; For the temperature data sequence, the first The lowest temperature of the day; It represents the 95th percentile of the historical lowest temperature in the area where the new energy city power grid is located; d For day ordinal numbers, when At that time, the first d This day is a cold wave day.

[0022] More preferably,

[0023] The pumped storage unit operates under both turbine and pump conditions.

[0024] When a three-phase short-circuit fault occurs in the new energy urban power grid system, the short-circuit current supplied by the pumped storage unit to the short-circuit fault point under different operating conditions is determined as follows:

[0025] Short-circuit current under turbine operating conditions Specifically:

[0026]

[0027] Short-circuit current under water pump operating conditions Specifically:

[0028]

[0029] in, For AC system voltage; For network equivalent transfer reactance; For the subtransient reactance of the pumped storage unit; The equivalent positive sequence reactance between the fault point and the pumped storage unit connection point; It is the ratio of the remaining voltage at the fault point to the reference voltage of the AC system.

[0030] More preferably,

[0031] The aforementioned new energy urban power grid source-storage coordinated planning model has an objective function that minimizes the sum of system planning cost, maintenance cost, and operating cost. The operating cost is obtained by weighting the operating costs under each typical scenario based on their respective probabilities of occurrence. Specifically:

[0032]

[0033] in, For system operating costs, , , , , , Don't be a typical scenario The costs of purchasing electricity from the power grid, the coal consumption cost of thermal power units, the start-up and shutdown costs of thermal power units, the load shedding cost, the cost of curtailed electricity, and the start-up and shutdown costs of pumped storage units; The total number of days in a calendar year; This represents the number of typical days in a normal scenario. This is the sum of the number of heat wave days and the number of cold wave days in a heat wave scenario; Typical scenario Probability of occurrence.

[0034] More preferably,

[0035] The short-circuit capacity of the pumped storage unit is determined as follows:

[0036]

[0037] in, For typical days Next period node The short-circuit capacity provided by pumped storage units in an AC system; For typical days Next period node Operating conditions of pumped storage units under AC system The provided short-circuit current, This is the rated voltage.

[0038] More preferably,

[0039] The short-circuit ratio constraint at the grid connection point is specifically as follows:

[0040]

[0041] in, For typical days Next period node The short-circuit capacity provided by pumped storage units in an AC system; , Typical days Next period node , The output of new energy sources; This is the critical short-circuit ratio. The voltage interaction factor between new energy power stations, and satisfying the following conditions. ,in, , They are the grid connection points , The voltage; , These are the system mutual impedance and the self-impedance, respectively.

[0042] Secondly, this invention discloses a new energy urban power grid source-storage coordinated planning system based on the aforementioned method and taking into account safety constraints, including a typical scenario generation module, a pumped storage unit short-circuit current calculation module, a new energy urban power grid source-storage coordinated planning model construction module, and a model solving and output decision module.

[0043] The typical scenario generation module generates typical scenarios based on historical temperature data of the area where the new energy urban power grid is located; the typical scenarios include heat wave scenarios, cold wave scenarios, and normal scenarios; the new energy urban power grid includes pumped storage units;

[0044] The pumped storage unit short-circuit current calculation module calculates the short-circuit current provided by the pumped storage unit to the short-circuit fault point under different operating conditions based on the operating status and equivalent model of the pumped storage unit under different operating conditions in the new energy urban power grid.

[0045] A module for constructing a new energy city power grid source-storage coordinated planning model is provided. This module constructs a new energy city power grid source-storage coordinated planning model that includes various typical scenarios. The model introduces grid connection point short-circuit ratio constraints, including the short-circuit capacity of pumped storage units. The short-circuit capacity of the pumped storage units is calculated based on the short-circuit current provided by the pumped storage units to the short-circuit fault point under different operating conditions.

[0046] The model solving and output decision module solves the source-storage collaborative planning model to obtain the output of each device in the new energy urban power grid under various typical scenarios.

[0047] Thirdly, the present invention provides a terminal, including a processor and a storage medium;

[0048] The storage medium is used to store instructions;

[0049] The processor is configured to operate according to the instructions to perform the steps of the method according to any one of the first aspects of the present invention.

[0050] Fourthly, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described in any one of the first aspects of the present invention.

[0051] The beneficial effects of this invention are compared with those of the prior art:

[0052] This invention significantly improves grid voltage stability under high-proportion renewable energy integration. It introduces a short-circuit ratio constraint at the grid connection point into the planning model and quantifies the short-circuit capacity provided by pumped storage units under different operating conditions. This enables the planning scheme to proactively and precisely allocate synchronous support resources, ensuring that the short-circuit ratio at the renewable energy grid connection point is always higher than the safety threshold. This prevents voltage instability or collapse risks caused by insufficient system strength and addresses the shortcomings of existing planning methods that only consider power balance while neglecting voltage stability. It also enhances the resilience and power supply reliability of the grid under extreme weather events.

[0053] By accurately identifying heat waves and cold waves and extracting typical scenarios, and embedding the source-load characteristics and equipment operation constraints under extreme weather conditions into the optimization model, the planning results can effectively cope with the drastic fluctuations in load and renewable energy output under extreme climate conditions. This ensures the continuous availability of pumped storage power stations, which serve as regulating resources, under the worst weather conditions. Compared with existing technologies, which only focus on supply and demand balance under extreme climate conditions and cannot solve the problems of reduced system short-circuit capacity, excessively low short-circuit ratio at grid connection points, and increased voltage stability risks caused by high renewable energy penetration, this invention provides a source-storage coordinated planning method and system for high-penetration renewable energy urban power grids that simultaneously considers both short-circuit ratio safety and supply and demand safety constraints. By embedding the short-circuit ratio constraint into the optimization model, the short-circuit capacity support capability of pumped storage is deeply utilized, proactively ensuring the voltage stability of the power grid during the planning stage, and simultaneously solving the two major problems of power grid voltage stability and supply and demand balance.

[0054] By accurately identifying heat waves and cold waves and extracting typical scenarios, the planning results are better adapted to load and renewable energy output fluctuations under extreme weather conditions, thereby improving grid resilience and power supply reliability. Minimum operating time constraints for pumped storage units on cold wave days are embedded in the optimization model to prevent reservoir freezing, ensure the availability of pumped storage power stations under extreme low temperatures, and avoid a decrease in system regulation capacity due to equipment freezing. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of a new energy urban power grid source-storage coordinated planning method that takes into account safety constraints, as described in this invention. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The embodiments described in this application are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this invention.

[0057] like Figure 1 As shown, this invention discloses a source-storage coordinated planning method for new energy urban power grids that takes into account safety constraints, comprising the following steps:

[0058] Based on historical temperature data of the area where the new energy urban power grid is located, typical scenarios are generated; the typical scenarios include heat wave scenarios, cold wave scenarios, and normal scenarios; the new energy urban power grid includes pumped storage units.

[0059] The heat wave scenario is a set of power curves for renewable energy output and load demand on heat wave days; the cold wave scenario is a set of power curves for renewable energy output and load demand on cold wave days; the normal scenario is a set of power curves for renewable energy output and load demand on neither heat wave nor cold wave days.

[0060] The heatwave day is based on the heatwave day judgment index. Confirmed, the heatwave day judgment index Specifically:

[0061]

[0062] in, It is a step function; For the temperature data sequence, the first The highest temperature of the day; The 95th percentile of the highest historical temperature in the area where the new energy city power grid is located; d For day ordinal numbers, when At that time, the first d The day was a heatwave day;

[0063] The cold wave day is based on the cold wave day judgment index. Confirmed, the cold wave day judgment index Specifically:

[0064]

[0065] in, It is a step function; For the temperature data sequence, the first The lowest temperature of the day; It represents the 95th percentile of the historical lowest temperature in the area where the new energy city power grid is located; d For day ordinal numbers, when At that time, the first d This day is a cold wave day.

[0066] Based on the operating status and equivalent model of pumped storage units under different operating conditions, the short-circuit current provided by pumped storage units to the short-circuit fault point under different operating conditions is calculated when a short-circuit fault occurs in the new energy urban power grid.

[0067] The pumped storage unit operates under both turbine and pump conditions.

[0068] When a three-phase short-circuit fault occurs in the new energy urban power grid system, the short-circuit current supplied by the pumped storage unit to the short-circuit fault point under different operating conditions is determined as follows:

[0069] Short-circuit current under turbine operating conditions Specifically:

[0070]

[0071] Short-circuit current under water pump operating conditions Specifically:

[0072]

[0073] in, For AC system voltage; For network equivalent transfer reactance; For the subtransient reactance of the pumped storage unit; The equivalent positive sequence reactance between the fault point and the pumped storage unit connection point; It is the ratio of the remaining voltage at the fault point to the reference voltage of the AC system.

[0074] A new energy urban power grid source-storage coordinated planning model is constructed, which includes various typical scenarios. The model introduces grid connection point short-circuit ratio constraints, including the short-circuit capacity of pumped storage units. The short-circuit capacity of pumped storage units is calculated based on the short-circuit current provided by pumped storage units to the short-circuit fault point under different operating conditions.

[0075] The aforementioned new energy urban power grid source-storage coordinated planning model has an objective function that minimizes the sum of system planning cost, maintenance cost, and operating cost. The operating cost is obtained by weighting the operating costs under each typical scenario based on their respective probabilities of occurrence. Specifically:

[0076]

[0077] in, For system operating costs, , , , , , Don't be a typical scenario The costs of purchasing electricity from the power grid, the coal consumption cost of thermal power units, the start-up and shutdown costs of thermal power units, the load shedding cost, the cost of curtailed electricity, and the start-up and shutdown costs of pumped storage units; The total number of days in a calendar year; This represents the number of typical days in a normal scenario. This is the sum of the number of heat wave days and the number of cold wave days in a heat wave scenario; Typical scenario Probability of occurrence.

[0078] The short-circuit capacity of the pumped storage unit is determined as follows:

[0079]

[0080] in, For typical days Next period node The short-circuit capacity provided by pumped storage units in an AC system; For typical days Next period node Operating conditions of pumped storage units under AC system The provided short-circuit current, This is the rated voltage.

[0081] The short-circuit ratio constraint at the grid connection point is specifically as follows:

[0082]

[0083] in, For typical days Next period node The short-circuit capacity provided by pumped storage units in an AC system; , Typical days Next period node , The output of new energy sources; This is the critical short-circuit ratio. The voltage interaction factor between new energy power stations, and satisfying the following conditions. ,in, , They are the grid connection points , The voltage; , These are the system mutual impedance and the self-impedance, respectively.

[0084] The source-storage collaborative planning model is solved to obtain the power output of each device in the new energy urban power grid under various typical scenarios.

[0085] The present invention also discloses a new energy urban power grid source-storage coordinated planning system based on the aforementioned method and taking into account safety constraints, including a typical scenario generation module, a pumped storage unit short-circuit current calculation module, a new energy urban power grid source-storage coordinated planning model construction module, and a model solving and output decision module;

[0086] The typical scenario generation module generates typical scenarios based on historical temperature data of the area where the new energy urban power grid is located; the typical scenarios include heat wave scenarios, cold wave scenarios, and normal scenarios; the new energy urban power grid includes pumped storage units;

[0087] The pumped storage unit short-circuit current calculation module calculates the short-circuit current provided by the pumped storage unit to the short-circuit fault point under different operating conditions based on the operating status and equivalent model of the pumped storage unit under different operating conditions in the new energy urban power grid.

[0088] A module for constructing a new energy city power grid source-storage coordinated planning model is provided. This module constructs a new energy city power grid source-storage coordinated planning model that includes various typical scenarios. The model introduces grid connection point short-circuit ratio constraints, including the short-circuit capacity of pumped storage units. The short-circuit capacity of the pumped storage units is calculated based on the short-circuit current provided by the pumped storage units to the short-circuit fault point under different operating conditions.

[0089] The model solving and output decision module solves the source-storage collaborative planning model to obtain the output of each device in the new energy urban power grid under various typical scenarios.

[0090] Example 1:

[0091] like Figure 1 As shown, this invention discloses a source-storage coordinated planning method for new energy urban power grids that takes into account safety constraints, comprising the following steps:

[0092] Step 1: Generate typical scenarios based on historical temperature data of the area where the new energy city power grid is located; the typical scenarios include heat wave scenarios, cold wave scenarios, and normal scenarios;

[0093] The new energy urban power grid includes wind turbines, photovoltaic systems, thermal power units, and pumped storage units;

[0094] There are multiple standards for defining heat waves and cold waves, and these definitions may vary between different regions. The China Meteorological Administration uses fixed thresholds for defining heat waves and cold waves at individual stations. However, over a larger spatial area, these thresholds correspond to different temperature percentiles in different regions. Therefore, this paper uses relative thresholds to define heat waves and cold waves to reflect the climate differences between different regions.

[0095] The criterion for determining high-temperature days in areas where new energy urban power grids are located is that the highest temperature of that day exceeds the 95th percentile of the region's historical daily high temperature. A heatwave event is defined as a region experiencing three or more consecutive days of high temperatures. The criteria for determining heatwave days are as follows: As shown in equation (1).

[0096] (1)

[0097] In the formula, It is a step function; For the temperature data sequence, the first The highest temperature of the day; The 95th percentile of the highest historical temperature in the area where the new energy city power grid is located; d For day ordinal numbers, when At that time, the first d The day is a heatwave day.

[0098] The criterion for determining a region's lowest temperature day is that the day's minimum temperature is less than the 95th percentile of the region's historical daily minimum temperatures. A cold wave event is defined as a region experiencing three or more consecutive days of low temperatures. The criteria for determining cold wave days are as follows: As shown in equation (2).

[0099] (2)

[0100] In the formula, It is a step function; For the temperature data sequence, the first The lowest temperature of the day; It represents the 95th percentile of the historical lowest temperature in the area where the new energy city power grid is located; d For day ordinal numbers, when At that time, the first d This day is a cold wave day.

[0101] Heat waves and cold waves typically occur in summer and winter, respectively. Based on the region's historical weather data for the whole year, we identify historical heat waves and cold waves, and extract typical power curves of wind power, photovoltaic power, pumped storage power stations and loads on heat wave days and cold wave days.

[0102] Taking the extraction of heatwave scenes as an example, the specific extraction steps are as follows:

[0103] Step 1.1: Input the original sample sequence set for the entire year of several historical years. ,in, For the first i A sequence of daily maximum temperatures for each year; The total number of years included in the analysis;

[0104] Step 1.2: Assume the width of the observation window and its sliding step size are both 1 day. Extracting the first Sequences Identify its length as Day, in sequence Two days were randomly selected, and their sample data were added to the sequence. The beginning and end of the sequence are used to increase the sequence length to . Day, position of observation window ;

[0105] Step 1.3: Calculate the first step using equation (1). d Daily judgment indicators ,like At that time, the first d Define a day as a heat wave day, otherwise define it as a transition day. Use a sliding window to... ;

[0106] Step 1.4: If Then proceed to step 3; if Then proceed to step 1.5;

[0107] Step 1.5: Classify the unlabeled sample days in the sequence into typical days under the normal scenario of that season according to their season;

[0108] Step 1.6: Determine if the collection has been traversed. If all elements in the list are not found, proceed to step 1.2; otherwise, proceed to step 1.7.

[0109] Step 1.7: Calculate the proportion of heat wave days in the original annual sample sequence set for several historical years. Extract the renewable energy output and load demand curves for all heat wave days into a set. By using k-means clustering, we obtained the typical source-load power curves for meteorological coupled heat wave days and typical days in each season.

[0110] The extraction method for cold wave scenarios is the same as that for heat wave scenarios. Simply change the highest temperature sequence to the lowest temperature sequence and change the identification of heat wave days to the identification of cold wave days.

[0111] The typical scenario is the set of typical power curves of wind power, photovoltaic power, hydropower and load under non-heat wave days and non-cold wave days in the original sample sequence set of several years of history.

[0112] Step 2: Based on the operating status and equivalent model of the pumped storage unit under different operating conditions, calculate the short-circuit current provided by the pumped storage unit to the short-circuit fault point under different operating conditions when a short-circuit fault occurs in the new energy urban power grid.

[0113] The impact of pumped storage units on the short-circuit capacity of the system under different operating conditions can be quantitatively analyzed through their operating status and the equivalent model of the motor. The operating conditions of the pumped storage units include turbine operating conditions and pump operating conditions.

[0114] Taking a synchronous generator unit as an example, when a three-phase short-circuit fault occurs, the short-circuit current it can provide under turbine and pump operating conditions theoretically differs to some extent, specifically:

[0115] Turbine operating conditions:

[0116] Pumped-storage hydroelectric units operate as generators, outputting active and reactive power to the system. During a short circuit, the unit provides a short-circuit current to the fault point through its internal electromotive force. The magnitude is determined by the subtransient reactance With subtransient electromotive force Decide:

[0117] (3)

[0118] In short-circuit calculations, it is usually assumed that... equal to the system rated voltage Ignore operating power Subtle effects.

[0119] Water pump operating conditions:

[0120] Pumped-storage hydroelectric units operate as electric motors, absorbing active power from the system (pumping water) and potentially absorbing or generating reactive power. During a short circuit, if the voltage doesn't completely collapse, the unit's inertia maintains its speed, which is equivalent to a generator feedback short-circuit current. The magnitude of the short-circuit current it provides to the fault point is similar to that of a generator under similar operating conditions. Driven by the residual voltage at the fault point, the short-circuit current decays rapidly due to the loss of power.

[0121] (4)

[0122] In the formula, The remaining voltage at the fault point; It is the ratio of the remaining voltage at the fault point to the reference voltage of the AC system.

[0123] Subtransient reactance These are inherent parameters of the motor, determined after the motor design is completed, and do not change with operating power, voltage, or operating conditions. Therefore, the difference in short-circuit current provided by the pumped storage unit to the system under different operating conditions depends on the terminal voltage.

[0124] When a pumped-storage hydroelectric unit is connected to the AC system of a new energy city power grid and a three-phase short-circuit fault occurs, if the pumped-storage hydroelectric unit is in a shutdown state, the short-circuit current flowing into the fault point will... for:

[0125] (5)

[0126] In the formula, For AC system voltage; For network equivalent transfer reactance; It is the equivalent positive sequence reactance between the fault point and the pumped storage unit connection point.

[0127] When the pumped storage unit is in turbine operation mode, the short-circuit current flowing into the fault point will become :

[0128] (6)

[0129] When the pumped storage unit is in pump operation mode, the short-circuit current flowing into the fault point will become It can be calculated using the superposition theorem.

[0130] (7)

[0131] The above analysis shows that when pumped storage units are put into operation, they can increase the system short-circuit current and thus improve the system short-circuit capacity, regardless of the operating conditions. Furthermore, due to the inherent properties of the system's grid structure, the contribution of synchronous machines to the system short-circuit current varies depending on their location at different nodes; the closer the electrical distance, the greater the short-circuit capacity they contribute.

[0132] Step 3: Construct a new energy urban power grid source-storage coordinated planning model that includes various typical scenarios. In the model, introduce grid connection point short-circuit ratio constraints including the short-circuit capacity of pumped storage units. The short-circuit capacity of pumped storage units is calculated based on the short-circuit current provided by pumped storage units to the short-circuit fault point under different operating conditions.

[0133] The proposed new energy urban power grid source-storage coordinated planning model aims to minimize the sum of the average annual planning cost over the entire lifecycle of urban power grid power source and energy storage expansion planning and the total annual operating cost of the system after planning. The target includes planning costs, maintenance costs, and system operating costs, namely:

[0134] (8)

[0135] In the formula, Cost of equipment planning; To maintain costs; This refers to the system operating cost.

[0136] Planning costs This mainly includes the construction costs of various equipment. For pumped storage power stations built on existing large reservoirs, rivers, or lakes, only the planning costs of the upper reservoir need to be considered. Specifically:

[0137] (9)

[0138] In the formula, The discount rate; For equipment Service life; For equipment Planning costs, including wind power planning costs Photovoltaic planning costs Planning costs of pumped storage power stations ; , , , , These are the unit capacity planning costs for wind power, photovoltaic power, constant-speed pumped storage units, variable-speed pumped storage units, and upper reservoirs, respectively. , These are the rated installed capacities of wind power and photovoltaic power, respectively. , The first Taiwan constant-speed pumped storage unit, the first Rated installed capacity of the variable speed pumped storage unit; The planned capacity of the upper reservoir; , These refer to the number of fixed-speed and variable-speed pumped storage units, respectively.

[0139] Maintenance costs This mainly includes the maintenance costs of wind power, photovoltaic, and pumped storage power stations; specifically:

[0140] (10)

[0141] In the formula, , , The annual maintenance costs are for wind power, solar power, and pumped storage power stations, respectively. , , , , The annual maintenance costs per unit capacity for wind power, photovoltaic power, constant-speed pumped storage units, variable-speed pumped storage units, and upper reservoirs are respectively. , The figures represent the annual dismantling and maintenance costs for fixed-speed and variable-speed pumped storage units, respectively.

[0142] System operating costs This mainly includes electricity purchase costs, coal consumption costs and start-up and shutdown costs of thermal power units, load shedding costs, curtailment penalty costs, and start-up and shutdown costs of pumped storage units; specifically:

[0143] (11)

[0144] (12)

[0145] In the formula, , , , , , Don't be a typical scenario The costs of purchasing electricity from the power grid, the coal consumption cost of thermal power units, the start-up and shutdown costs of thermal power units, the load shedding cost, the cost of curtailed electricity, and the start-up and shutdown costs of pumped storage units; The total number of days in a calendar year; This represents the number of typical days. This is the sum of the number of typical heat wave days and cold wave days; Typical scenario The probability of occurrence is the proportion of each type of typical day in the set of original sample sequences of several years of history extracted by the scene extraction method in step 1. Typical scenario Total number of time periods; , , These are the unit electricity purchase cost of the power grid, the unit load shedding cost, and the unit electricity curtailment cost, respectively. , , These are the constant, linear, and quadratic coefficients of the coal consumption cost for thermal power plants, respectively. , For example, thermal power units in different scenarios Next period Start-up and shutdown costs; , Pumped storage units in different scenarios Next period Start-up and shutdown costs; , , , Typical scenarios Next period The system's purchased power, thermal power unit output, system load shedding power, and system abandoned power.

[0146] The annual planned cost of various equipment in the urban power grid needs to meet a certain upper limit, as shown in Equation (13); the upper limit of the planned capacity of various distributed new energy sources is specified according to the local wind and solar resources and economic development status, and the upper limit of the planned capacity of the upper reservoir is specified according to the actual conditions of the candidate sites of pumped storage power stations, as shown in Equation (14).

[0147] (13)

[0148] (14)

[0149] In the formula, This represents the maximum average annual investment budget. , , These are the planned capacity limits for the upper reservoirs of wind power, photovoltaic, and pumped storage power stations, respectively.

[0150] During operation, the output range of a thermal power unit is limited by the minimum technical output and rated power, as shown in Equation (15); the uphill and downhill climbing constraints of a thermal power unit are shown in Equation (16); in addition, the start-up and shutdown of a thermal power unit must be maintained for a period of time to prevent damage caused by frequent start-up and shutdown of the unit, as shown in Equation (17).

[0151] (15)

[0152] (16)

[0153] (17)

[0154] In the formula, For the scene Next period Start-up and shutdown status of thermal power units. This indicates that the generator unit has stopped. This indicates that the generator unit has started operation; For the scene Next period Power output of thermal power units; Minimize the technical output of thermal power units; , Do not set the upper and lower limits for the ramp power of thermal power units per unit time; , Scenes Next period Unit operating and downtime; , These are the minimum operating and downtime of the unit, respectively.

[0155] Constant-speed pumped storage units and variable-speed pumped storage units can only operate in pump mode or turbine mode at any time, as shown in equation (18) and equation (19) respectively.

[0156] (18)

[0157] (19)

[0158] In the formula, For the scene Next period Constant speed hydro storage unit The operating status variables of the water pump; For the scene Next period Constant speed pumped storage unit The operating state variables of the water turbine; For the scene Next period Variable speed pumped storage unit The operating status variables of the water pump; For the scene Next period Variable speed pumped storage unit The operating state variables of the water turbine.

[0159] The power constraints of constant-speed pumped storage units and variable-speed pumped storage units when operating in pump and turbine modes are shown in Equations (20) and (21), respectively.

[0160] (20)

[0161] (twenty one)

[0162] In the formula, , Scenes Next period Constant speed pumped storage unit The operating power of water pumps and turbines under operating conditions; , These are constant-speed pumped storage units Rated pump power and rated turbine power; , These are the minimum and maximum output coefficients of a constant-speed pumped storage unit under turbine operating conditions. , Scenes Next period Variable speed pumped storage unit The operating power of water pumps and turbines under operating conditions; , These are variable speed pumped storage units Rated pump power and rated turbine power; , These are the minimum and maximum output coefficients of the variable speed pumped storage unit under pump operating conditions, respectively. , These are the minimum and maximum output coefficients of a constant-speed pumped storage unit turbine under operating conditions.

[0163] In addition, low temperatures can cause ice to form in front of the dam. If the pumped storage power station is not in operation for a long time, the water cannot flow and may cause the reservoir to freeze. Therefore, during cold waves, the pumped storage units need to be operated in pump or turbine mode for more than 8 hours to prevent the formation of a complete ice cover in the upper reservoir, as shown in equation (22).

[0164] (twenty two)

[0165] In the formula, This is a typical cold wave day.

[0166] The operating range constraints of the upper reservoir are shown in Equation (23); the water storage change constraints of the upper reservoir are shown in Equation (24); in addition, the water storage of the upper reservoir at the beginning and end of each day must be equal, as shown in Equation (25).

[0167] (twenty three)

[0168] (twenty four)

[0169] (25)

[0170] (26)

[0171] In the formula, For the scene Next period Upper reservoir water storage capacity; The minimum storage capacity coefficient for the upper reservoir is taken as 0.15 in this paper; This indicates the rated capacity of the upper reservoir; , These are the conversion coefficients between pumped water pumping, power generation, and flow rate in pumped storage hydropower. , Scenes The water storage volume of the upper reservoir at the initial and final moments; , These refer to the pumping efficiency and power generation efficiency of the pumped storage unit, respectively. , These are the average density of water and the acceleration due to gravity, respectively. The average head difference between the upper and lower reservoirs is set to 100 meters. The energy contained in one kilowatt-hour of electrical energy, measured in joules.

[0172] With a time interval of 1 hour, the power balance constraint is established as shown in equation (27).

[0173] (27)

[0174] In the formula, , Scenes Next period Load demand power and load shedding amount; , , , Scenes Next period External transmission line power, wind turbine power, photovoltaic power, and abandoned power.

[0175] External transmission lines are an important source of electricity for urban power grids. Due to the physical characteristics of the lines, they need to meet the upper limit constraint of transmission capacity as shown in Equation (28). In addition, in order to ensure the overall stability of the power system, transmission lines also need to meet the power change constraint as shown in Equation (29).

[0176] (28)

[0177] (29)

[0178] In the formula, This represents the maximum transmission power of the external power transmission line. This represents the maximum change in power transmitted by external power transmission lines per unit time.

[0179] Synchronous generators increase the system's short-circuit capacity, thereby improving the short-circuit ratio at the grid connection point of new energy sources, to achieve a critical short-circuit ratio value. As a boundary value for judging the stability of new energy grid connection points, when the short-circuit ratio of the new energy grid connection point is less than... At that time, the grid connection point system was weak. In this embodiment, The preferred value is 2; thus, the short-circuit ratio constraint at the grid connection point can be obtained as shown in equation (30).

[0180] (30)

[0181] (31)

[0182] (32)

[0183] In the formula For typical days Next period node Operating conditions of pumped storage units under AC system Provided short-circuit current, under different operating conditions The short-circuit current obtained by the aforementioned formulas (6) and (7) is used for calculation; For typical days Next period node The short-circuit capacity provided by pumped storage units in an AC system; , Typical days Next period node , The output of new energy sources; The voltage interaction factor between new energy power stations; , They are the grid connection points , The voltage; , These are the system mutual impedance and the self-impedance, respectively.

[0184] Step 4: Solve the source-storage collaborative planning model to obtain the power output of each device in the new energy urban power grid under various typical scenarios;

[0185] The collaborative planning model for distributed new energy and pumped storage power stations proposed in this invention is a mixed-integer nonlinear optimization problem with numerous and highly correlated decision variables. Traditional heuristic algorithms are prone to getting trapped in local optima. Therefore, a phased and hierarchical approach is used to solve the model step by step.

[0186] First, the model is linearized, taking 0-1 variables from the constraints as an example. With continuous variables Nonlinear constraints resulting from multiplication introduce new variables. Alternative The linearized result using the Big M method is shown in equation (33).

[0187] (33)

[0188] All nonlinear constraints involving the multiplication of 0-1 variables with continuous variables in the paper are linearized using the method described above.

[0189] The above solution strategy is a linear optimization model. After obtaining the alternative schemes for pumped storage unit assembly, the highly convergent adaptive chaotic particle swarm optimization algorithm is selected to solve the model, and the GUROBI solver is called to solve for the optimal planning and operating cost.

[0190] Example 2:

[0191] An embodiment of the present invention provides a terminal, including a processor and a storage medium;

[0192] The storage medium is used to store instructions;

[0193] The processor is configured to operate according to the instructions to perform the steps of the method according to any one of Embodiment 1.

[0194] Example 3:

[0195] The present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described in any one of the embodiments.

[0196] This disclosure can be a system, method, and / or computer program product. A computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for causing a processor to implement various aspects of this disclosure.

[0197] Computer-readable storage media can be tangible devices capable of holding and storing instructions for use by an instruction execution device. Computer-readable storage media can be, for example—but not limited to—electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination of the foregoing. The computer-readable storage media used herein are not to be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0198] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0199] Computer program instructions used to perform the operations of this disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing the status information of the computer-readable program instructions to implement various aspects of this disclosure.

[0200] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A method for source-storage collaborative planning of a new energy urban power grid considering security constraints, characterized in that, The method comprises the following steps: generating typical scenarios based on historical temperature data of a region where a new energy city power grid is located; the typical scenarios include a heat wave scenario, a cold wave scenario, and a normal scenario; the new energy city power grid comprises pumped storage units; calculating short-circuit currents provided by the pumped storage units to a short-circuit fault point in different operating conditions of the pumped storage units based on operating states and equivalent models of the pumped storage units in the different operating conditions; constructing a new energy city power grid source-storage coordination planning model comprising the typical scenarios, and introducing a grid-connected point short-circuit ratio constraint comprising a short-circuit capacity of the pumped storage units in the model; the short-circuit capacity of the pumped storage units is calculated based on the short-circuit currents provided by the pumped storage units to the short-circuit fault point in different operating conditions of the pumped storage units; solving the source-storage coordination planning model to obtain outputs of each device in the new energy city power grid in each typical scenario.

2. The new energy city power grid source-storage coordination planning method according to claim 1, wherein: the heat wave scenario is a power curve set of renewable energy output and load demand on a heat wave day; the cold wave scenario is a power curve set of renewable energy output and load demand on a cold wave day; and the normal scenario is a power curve set of renewable energy output and load demand on a day that is neither a heat wave day nor a cold wave day.

3. The new energy city power grid source-storage coordination planning method according to claim 2, wherein: The heat wave day is based on a heat wave day judgment index It is determined that the heat wave day judgment index Specifically: wherein, is a step function; is the maximum temperature on day in the temperature data sequence; is the 95th percentile of the historical maximum temperature in the region where the new energy city power grid is located; d is the day serial number, when , the d day is a heat wave day; The cold wave day is determined based on the cold wave day determination index It is determined that the cold wave day determination index Specifically: wherein, is a step function; is the minimum temperature of the day in the temperature data sequence; is the 95th percentile of the historical minimum temperature of the region where the new energy city power grid is located; d is the day serial number, when the d day is the cold wave day.

4. The new energy city power grid source-storage coordination planning method according to claim 1, wherein: the operating conditions of the pumped storage units comprise a water turbine condition and a water pump condition; when a three-phase short-circuit fault occurs in the new energy city power grid system, the short-circuit currents provided by the pumped storage units to the short-circuit fault point in different operating conditions of the pumped storage units are determined in the following manner: Short circuit current in the operating mode of a hydraulic turbine In particular: Short circuit current in water pump operating condition In particular: wherein, is the AC system voltage; is the network equivalent transfer reactance; is the sub-transient reactance of the pumped storage unit; is the equivalent positive sequence reactance between the fault point and the pumped storage unit access point; is the proportional coefficient of the fault point residual voltage and the AC system reference voltage.

5. The new energy city power grid source-storage coordination planning method according to claim 4, wherein: the objective function of the new energy city power grid source-storage coordination planning model is the minimum value of the sum of system planning cost, maintenance cost, and operating cost, wherein the operating cost is obtained by weighting operating costs in each typical scenario based on probabilities of occurrence of the respective scenarios, and is specifically: wherein, is the system operation cost, , , , , , is the grid purchase cost of the power grid, is the coal consumption cost of the thermal power unit, the start-stop cost of the thermal power unit, the load shedding cost, the curtailment cost, and the start-stop cost of the pumped storage unit; is the total number of days in a natural year; is the number of typical days under the conventional scenario; is the sum of the number of heat wave days under the heat wave scenario and the number of cold wave days under the heat wave scenario; is the grid purchase cost of the power grid, is the appearance probability.

6. The new energy city power grid source-storage coordination planning method according to claim 1 or 5, wherein: the short-circuit capacity of the pumped storage units is determined in the following manner: in, For typical days Next period node The short-circuit capacity provided by pumped storage units in an AC system; For typical days Next period node Under AC system conditions, pumped storage units are in operation. The short-circuit current provided below This is the rated voltage.

7. The new energy city power grid source-storage coordination planning method according to claim 6, wherein: the grid-connected point short-circuit ratio constraint is specifically: wherein, is the typical day is the time interval is the node is the short circuit capacity provided by pumped storage units under AC system; , is the typical day is the time interval is the node , is the new energy output; is the critical short circuit ratio; is the voltage interaction factor between new energy stations, and satisfies wherein, , is the voltage at the grid-connected point , is the voltage at the grid-connected point , is the system mutual impedance and self impedance, respectively.

8. A new energy city power grid source-storage coordination planning system based on the method according to any one of claims 1 to 7, comprising a typical scenario generation module, a pumped storage unit short-circuit current calculation module, a new energy city power grid source-storage coordination planning model construction module, and a model solving and output decision module, wherein: The typical scene generation module generates typical scenes based on historical temperature data of a region where a new energy city power grid is located; the typical scenes include a heat wave scene, a cold wave scene, and a regular scene; the new energy city power grid includes a pumped storage unit; The pumped storage unit short-circuit current calculation module calculates short-circuit currents provided by the pumped storage unit to a short-circuit fault point under different operating conditions of the pumped storage unit based on operating states and equivalent models of the pumped storage unit under different operating conditions; The new energy city power grid source-storage coordination planning model construction module constructs a new energy city power grid source-storage coordination planning model containing each typical scene, and introduces a grid connection point short-circuit ratio constraint including a pumped storage unit short-circuit capacity in the model; the pumped storage unit short-circuit capacity is calculated based on the short-circuit currents provided by the pumped storage unit to the short-circuit fault point under different operating conditions; The model solving and output decision module solves the source-storage coordination planning model to obtain outputs of each device in the new energy city power grid under each typical scene. 9.A terminal, comprising a processor and a storage medium; characterized in that: The storage medium is configured to store instructions; The processor is configured to operate according to the instructions to perform the steps of the method according to any one of claims 1-7.

10. A computer readable storage medium having stored thereon a computer program, characterized in that The program is executed by the processor to implement the steps of the method according to any one of claims 1-7.

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