A regional power grid pumped storage power station group start-stop machine scheduling optimization method

Abstract

The application provides a regional power grid pumped storage power station group start-stop scheduling optimization method, comprising the following steps: setting a setting time for each working condition of each unit in all pumped storage power stations in the regional power grid, so that the total number of units simultaneously generating power, starting and stopping and pumping water, starting and stopping at the same time is less than a preset threshold; when the pumped storage power station generates power in a normal peak regulation starting and stopping condition and is in a adjustable load range, the total load of the power station is raised and lowered according to the slope of the load uniform speed change between adjacent two planned points and the setting time to smooth the power change of the pumped storage power station; when the frequency deviation of the regional power grid is greater than a preset setting value, a frequency reverse locking method is used to suspend the power generation starting and stopping, pumping water starting and stopping and load raising and lowering of the pumped storage unit which will cause the frequency deviation to expand. The application has the advantages of realizing flexible and flexible control of the pumped storage unit, enhancing the anti-disturbance ability of the power grid, greatly reducing the influence of pumped storage centralized start and stop on the power fluctuation of the power grid and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to power station optimal scheduling technology, and particularly to a method for optimizing the start-stop scheduling of a pumped storage power station group in a regional power grid. BACKGROUND

[0002] Pumped storage power stations are currently a mature energy storage technology that has been widely used globally, providing peak shaving, spinning reserve, emergency reserve, frequency regulation, phase modulation and other auxiliary services in a power grid. At present, the scheduling of pumped storage power stations in China is mostly undertaken by regional power grids, which are large cross-provincial power grids formed by interconnecting several adjacent provincial power grids through tie lines, and the main task of which is to guide and coordinate the safe, stable, high-quality and economic operation of each provincial power grid. With the explosive development of new energy and the increase in the peak-valley difference of system load, the demand for pumped storage power stations has also increased explosively, and the installed capacity of pumped storage power stations in China has ranked first in the world, and the number of pumped storage power stations and units scheduled in each regional power grid has also increased.

[0003] The most common auxiliary service mode of pumped storage power stations in a power grid is peak shaving, i.e., generating power at the peak of power grid load and pumping water at the trough of power grid load, and pumped storage units need to be converted between pumping and generating conditions multiple times in 24 hours. The power grid scheduling department formulates a 96-point day-ahead scheduling plan for the total output of pumped storage power stations according to the load and new energy output prediction, and the units of pumped storage power stations are automatically started and stopped and adjusted by the load according to the plan. The most significant advantage of pumped storage units is rapid start-stop and fast variable load rate. However, when multiple pumped storage units in a regional power grid are started and stopped at the same time, the load changes of multiple pumped storage units often do not match the load ramp rate of the power grid and the change in new energy output, which can easily cause fluctuations in the frequency of the power grid.

[0004] The common working condition conversions of pumped storage units include generating start, generating stop, pumping start and pumping stop. The impact of each working condition process on the frequency of the power grid is as follows:

[0005] Generating start includes four stages of starting auxiliary equipment, accelerating the water turbine, synchronizing and connecting to the grid, and increasing load. The most obvious uncontrollable factor is the length of time for synchronizing and connecting to the grid, which is related to the parameters of the grid at the moment of connection and the characteristics of the unit itself. Pumped storage units vibrate greatly at low load, and the transition process needs to be completed quickly. The characteristics of the generating start process result in an inability to accurately control the time of connection to the grid, and after connection to the grid, the load is increased to the minimum stable operating load Ph (generally above 50% of rated power) within tens of seconds. When multiple units in multiple power stations are connected to the grid at the same time and the load is quickly increased, the generated power of the power grid will increase sharply within 1-2 minutes, causing a high-frequency phenomenon.

[0006] Generating shutdown includes three stages: load reduction, unit disconnection, and unit coasting. Only the load reduction stage affects the grid frequency. Similar to generating startup, it faces the same vibration constraints. After the unit reduces its load to the minimum stable operating load (Ph), it needs to be quickly disconnected to reduce the operating time in the vibration zone. When multiple power plants and several units simultaneously reduce their load and shut down, it can cause a significant drop in grid power generation within 1-2 minutes, triggering low-frequency phenomena.

[0007] Pumping startup includes four stages: auxiliary machine startup, speed increase via SFC (Static Frequency Converter) or back-to-back drive, synchronization to SCP (Synchronous Condenser Pump), and SCP switching to pumping. The active power absorbed from the grid by SCP steady-state units is limited, so the impact of synchronization duration uncertainty is negligible. However, the time for non-variable speed units to switch from SCP to pumping is shorter, and the power consumed by pumping is essentially the rated power and cannot be adjusted. If multiple power plants and several units switch to pumping simultaneously, it will cause a significant surge in grid power consumption within one minute, triggering low-frequency phenomena.

[0008] Pumping shutdown includes three stages: load reduction, unit disconnection, and unit coasting. The load reduction stage of pumping shutdown affects the grid frequency, and the load reduction duration is also relatively short. If multiple power plants and several units pump shut down simultaneously, it will cause a sharp drop in grid power consumption within 1 minute, triggering high-frequency phenomena.

[0009] Therefore, in regional power grids with a large number of pumped storage power stations, it is necessary to consider how to reduce the impact of pumped storage unit start-up and shutdown processes on the power grid frequency from two aspects: peak shifting and optimizing the regulation performance of pumped storage power stations. This has become a technical problem that needs to be solved. Summary of the Invention

[0010] The purpose of this invention is to overcome the shortcomings of the existing technology and provide an optimization method for the start-up and shutdown scheduling of pumped storage power stations in a regional power grid.

[0011] This invention provides a method for optimizing the start-up and shutdown scheduling of pumped storage power station groups in a regional power grid, comprising the following steps:

[0012] Step 1: Set the setting time for each operating condition of each unit in all pumped storage power stations in the regional power grid, so that the total number of units that start and stop generating electricity and pumping water at the same time is less than the preset threshold.

[0013] Step 2: When the pumped storage power station is in normal peak-shaving start-up and shutdown mode and is within the adjustable load range, the total load of the power station is adjusted according to the slope of the uniform load change between two adjacent planned points and the set time, so as to smooth the power change of the pumped storage power station.

[0014] Step 3, when the frequency deviation of the regional power grid is greater than the preset setting value, the frequency reverse locking method is adopted, and the generation start-stop, pumping start-stop and load raising and lowering of the pumped storage unit which will make the frequency deviation expand are suspended.

[0015] Optionally, the step 1 specifically comprises the following steps.

[0016] Step 1.1, grouping all pumped storage power stations in the regional power grid according to the province-city control area where they are located;

[0017] Step 1.2, setting the setting time for each group of power stations, different setting time is adopted for different start-stop working conditions, specifically comprising the following steps:

[0018] Step 1.2.1, setting the setting time for generation start: only the first unit of each power station in each one-minute plan point sets the start time;

[0019] Step 1.2.2, setting the setting time for generation stop: only the last unit of each power station sets the setting time for generation stop;

[0020] Step 1.2.3, setting the setting time for pumping start: the pumping start unit is driven to the pumping and phase modulation working condition by the static frequency converter or back-to-back, and the setting time for pumping start is the time when the unit is switched from the pumping and phase modulation working condition to the pumping working condition;

[0021] Step 1.2.4, setting the setting time for pumping stop: the setting time for pumping stop is the starting time when the unit triggers the stop process from the pumping working condition.

[0022] Optionally, the step 1.2.1 specifically comprises:

[0023] It is defined that there are n pumped storage power stations in the same province-city group, and the allocation principle of the setting time is:

[0024] Firstly, the generation start setting time interval Tgos is obtained:

[0025]

[0026] Wherein, Tgsi is the time length from the generation start order of the first unit of pumped storage power station i to the grid connection, and Tgri is the shortest time length from the grid connection to the rated power of the first unit of pumped storage power station i;

[0027] Then, Tgos is rounded down to Tgos' in half a minute unit;

[0028] Then, the first unit of each power station in each plan point is set to the generation start setting time in the order of Tgsi+Tgri from small to large, that is, 1, 1+Tgos', …, 1+(n-1)Tgos' minutes.

[0029] Optionally, when multiple units are started up at the same planned point in the same power plant, the start-up time of the remaining units, excluding the first unit, is determined based on the start-up duration Tgsi and the minimum stable load value P. h The startup times of the remaining units were obtained using the following method:

[0030] The sum of the absolute values ​​of the power deviation P is obtained from the deviation of the actual load increase curve of the power plant from the slope between the two planned points. e According to P e The minimum value is used to obtain the start-up time of the remaining units;

[0031] in, P ai Let i be the total power generated by the power station at time i;

[0032] P si Let P be the power setpoint of the power station at time i. si =P c +(P n -P c ) / m*T i

[0033] P n For the target load at the next planned point, P c The initial load at the planned point before startup, m is the number of samples calculated within 15 minutes at a planned point, and T is the initial load at the planned point before startup. i Let i be the i-th sampling time point.

[0034] Optionally, step 1.2.2 specifically includes:

[0035] The generator shutdown setting interval is obtained using the following formula:

[0036]

[0037] Wherein, Tgdi represents the last unit of pumped storage power station i operating from its minimum stable operating load P. h The shortest time to unblock is calculated by rounding the calculated Tgod down to the nearest half-minute to obtain T. god ';

[0038] Then the last generating unit of each power station will be installed in sequence according to 7, 7+T god '、……、7+(n-1)T god The generator stops at a set time of 'minutes'.

[0039] Optionally, step 1.2.3 specifically includes:

[0040] The pump start-up interval is obtained using the following formula:

[0041]

[0042] Wherein, Tpsi is the time length of the unit of pumped storage power station i from SCP to pumping, Tpos calculated is rounded down to T pos ’ in half minute unit.

[0043] If only one unit in each planning point of each power station is pumped, the first unit is pumped in turn according to 1, 1+T pos ’……, 1+(n-1)T pos ’ minute setting time.

[0044] Alternatively, if two units in each planning point of each power station are pumped, the first unit is pumped in turn according to 1, 1+T pos ’ / 2……, 1+(n-1)T pos ’ / 2 minute setting time, and the second unit is pumped in turn according to 1+nT pos ’ / 2, 1+(n+1)T pos ’ / 2……, 1+(2n-1)T pos ’ / 2 minute setting time.

[0045] Alternatively, the step 1.2.4 specifically includes:

[0046] The pumping shutdown setting time interval is obtained by using the following formula:

[0047]

[0048] Wherein, Tpdi is the time length of the unit of pumped storage power station i from pumping steady state to disconnection, Tpod calculated is rounded down to T pod ’ in half minute unit.

[0049] If only one unit in each planning point of each power station is pumped, the first unit is pumped in turn according to 1, 1+T pod ’……, 1+(n-1)T pod ’ minute setting time; if two units in each planning point of each power station are pumped, the first unit is pumped in turn according to 1, 1+T pod ’ / 2……, 1+(n-1)T pod ’ / 2 minute setting time, and the second unit is pumped in turn according to 1+nT pod ’ / 2, 1+(n+1)T pod ’ / 2……, 1+(2n-1)T pod ’ / 2 minute setting time.

[0050] Alternatively, the step 2 specifically includes:

[0051] Step 2.1, when the first unit of the pumped storage power station generates electricity, first start up and connect to the grid according to the setting time, and then increase the load to the minimum stable load P h , and then increase the load to the target value according to the load change slope determined by the power difference between the previous and next plan points; if the unit reaches the minimum stable load, the load setting value P si is less than P h + P c , the minimum stable operation load P h is maintained unchanged until the load setting value increases to greater than or equal to P h + P c , and then the output is further increased, wherein P n is the target load of the next plan point, and P c is the initial load of the plan point before starting up;

[0052] Step 2.2, when the non-first unit of the pumped storage power station generates electricity, whether the first unit is started up according to the setting time or not, if the load of the newly started unit increases to the minimum stable operation load P h , and the load of the unit already in operation is greater than the setting load value corresponding to the load setting value curve with the rate at the current power station, the unit already in operation needs to reduce the output to make the actual power output of the whole station equal to the load setting value with the rate;

[0053] Step 2.3, when the power grid appears abnormal conditions and the pumped storage power station needs to be started up or shut down quickly, the real-time load instruction is issued through the emergency support instruction, at this time, the pumped storage unit increases or decreases the load at the maximum rate without smoothing the output according to the variable load rate of the peak shaving start-up and shutdown mode.

[0054] Optionally, the step 3 specifically comprises:

[0055] Step 3.1, before the pumped storage unit executes the power generation start-up or water pumping shutdown process, if the frequency deviation is less than the negative start-up and shutdown setting value, the execution of the power generation start-up or water pumping shutdown process is suspended, and the start-up and shutdown is continued after the frequency deviation is less than the setting value, wherein the frequency deviation = rated frequency of the power grid - real-time frequency of the power grid;

[0056] Step 3.2, before the pumped storage unit executes the power generation shutdown or water pumping start-up process, if the frequency deviation is greater than the positive start-up and shutdown setting value, the execution of the power generation shutdown or water pumping start-up process is suspended, and the start-up and shutdown is continued after the frequency deviation is less than the setting value;

[0057] Step 3.3, when the load of the pumped storage unit reaches the target value before the power generation start-up process, and is greater than the minimum stable operation load, if the frequency deviation is less than the negative load increase setting value, the current load is maintained unchanged until the frequency deviation is restored and the load increase is continued;

[0058] Step 3.4, when the pumped storage unit is in the process of generating and shutting down, if the frequency deviation is greater than the positive load shedding setting value, the current load is kept unchanged until the frequency deviation is restored and then the load shedding is continued.

[0059] Compared with the prior art, the present application has the following advantages:

[0060] The present application provides a regional power grid pumped storage power station group start-stop scheduling optimization method, which adopts the method of grouping pumped storage power stations by province and city and adjusting the start-stop time, and the pumped storage unit smoothly increases / decreases the load within the adjustable range, and combines the limitation of real-time frequency on start-stop and load increase / decrease, realizes flexible and flexible control of pumped storage units, enhances the anti-disturbance ability of the power grid, greatly reduces the impact of pumped storage concentration start-stop on power grid power fluctuation, can meet the diversified regulation demand of load peak shaving and new energy fluctuation suppression, and improves the scientific scheduling level of pumped storage power stations. BRIEF DESCRIPTION OF DRAWINGS

[0061] Figure 1 A flowchart of a regional power grid pumped storage power station group start-stop scheduling optimization method is provided for an embodiment of the present application;

[0062] Figure 2 A pumped storage power station non-first unit start-up power generation output curve and a load setting straight line diagram are provided for an embodiment of the present application. DETAILED DESCRIPTION

[0063] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the protection scope of the present application.

[0064] As shown in the drawings, Figure 1 The present application provides a regional power grid pumped storage power station group start-stop scheduling optimization method, mainly including the following steps:

[0065] Step 1, setting the setting time for each working condition of each unit in all pumped storage power stations in the regional power grid, so that the total number of units simultaneously generating and starting / stopping and pumped storage starting / stopping at the same time is less than a preset threshold;

[0066] Step 2, when the pumped storage power station is normally adjusted for peak shaving, the total load of the power station is adjusted according to the slope of the load between two adjacent plan points and the setting time, and the power of the pumped storage power station is smoothly adjusted.

[0067] Step 3, when the frequency deviation of the regional power grid is greater than the preset setting value, the frequency reverse locking method is used to suspend the generation start / stop, pumping start / stop and load adjustment of the pumped storage unit that will cause the frequency deviation to expand. Wherein, the frequency deviation of the power grid = rated frequency - real-time frequency; the frequency reverse locking method is a frequency regulation method used to suppress the continuous increase of the frequency deviation of the power grid, for example, when the frequency deviation is positive, the real-time frequency of the power grid is increased to increase the real-time frequency of the power grid, so that the frequency deviation returns to the normal range.

[0068] The pumped storage power station group start / stop scheduling optimization method provided by the embodiment can reduce the probability of large load surge / drop caused by simultaneous start / stop of multiple units as much as possible, realize flexible and flexible control of pumped storage units, enhance the anti-disturbance ability of the power grid, greatly reduce the impact of pumped storage concentration start / stop on power grid power fluctuation, meet the diversified regulation demand of load peak shaving and new energy fluctuation suppression, and improve the scientific scheduling level of pumped storage power stations.

[0069] Specifically, the pumped storage power station group start / stop scheduling optimization method provided by the embodiment includes the following steps:

[0070] (1) The start / stop setting time method is used to reduce the probability of large load surge / drop caused by simultaneous start / stop of multiple units as much as possible.

[0071] (1.1) Group all pumped storage power stations in the regional power grid according to the geographical location of the province and city, and allocate start / stop setting time within the group, which can effectively reduce the impact on provincial and municipal power balance regulation. Each group can include more than one power station.

[0072] (1.2) Different start / stop conditions use different setting times, as follows:

[0073] (1.2.1) Generation start: only the first unit in each power station at each plan point (one plan point is one minute) is provided with a start setting time. Assuming that there are n pumped storage power stations in the same provincial and municipal group, the allocation principle of the setting time is:

[0074] Generation start setting time interval (minutes):

[0075]

[0076] Among them, T gsi T is the time from the issuance of the start-up order to grid connection of the first generating unit of pumped storage power station i. gri This refers to the shortest time from grid connection to rated power for the first generating unit of pumped-storage power station i. To facilitate the implementation of T... gos After calculation, round down to the nearest half-minute to get T. gos When there are many pumped storage power stations in the group, T gos If the calculated value is less than half a minute, a separate pumped storage power station group needs to be set up.

[0077] Then the first generating unit at each planned point of each power station can be installed according to T. gsi +T gri In ascending order, the generator starts up at set times of 1, 1+Tgos', ..., 1+(n-1)Tgos' minutes.

[0078] When multiple (multiple units refer to two or more) generating units are started up at the same planned point in the same power plant, the start-up time of the remaining units is based on the start-up duration (i.e., the time from the issuance of the start-up order to grid connection) T. gsi and minimum stable load value P h The corresponding delay is calculated as the sum of the absolute values ​​of the slope deviations P between the actual load increase curve of the power plant and the two planned points. e Choose the power-on time point based on the principle of minimizing costs.

[0079] Sum of absolute values ​​of power deviation

[0080] Where P ai Let i be the total power generated by the power station at time i;

[0081] P si Let P be the power setpoint of the power station at time i. si =P c +(P n -P c ) / m*T i

[0082] Among them, P n For the target load at the next planned point, P c The initial load at the planned point before startup, m is the number of samples calculated within 15 minutes at a planned point, and T is the initial load at the planned point before startup. i Let i be the i-th sampling time point.

[0083] (1.2.2) Power Generation Shutdown: Only the last generating unit of each power station has a set shutdown time. The principle for allocating the shutdown time of the last generating unit of the power station is as follows:

[0084] Generator shutdown setting interval:

[0085]

[0086] wherein T gdi is the minimum stable operating load of the pumped storage power station i. h The minimum stable operating load of the pumped storage power station i. god is the minimum stable operating load of the pumped storage power station i. god The minimum stable operating load of the pumped storage power station i. god When the number of pumped storage power stations in a group is large, and the calculated value of T

[0087] The last unit of each power station can be sequentially shut down at the setting time of 7, 7+T god ', …, 7+(n-1)T god '.

[0088] The shutdown time of the remaining units is selected according to the minimum stable operating load P h , and the sum of the absolute values of the slopes between the load shedding curve of the power station and the two planned points P e .

[0089] (1.2.3) Pumping start: The pumping start unit is driven by a static frequency converter (SFC) / back-to-back to the pumping phase modulation (SCP) condition in advance, and the setting time is the time when the unit is switched from the SCP to the pumping condition. The SCP to pumping phase modulation setting time interval is obtained using the following formula:

[0090]

[0091] wherein T psi is the time length of the unit of the pumped storage power station i switched from the SCP to the pumping condition. For ease of implementation, T pos is calculated and rounded down to the nearest half minute to obtain T pos '. When the number of pumped storage power stations in a group is large, and the calculated value of T pos is less than max(Tps1, Tpsi, …, Tpsn), another pumped storage power station group needs to be set.

[0092] If only one unit in each power station at each planned point is switched to pumping, the units can be sequentially switched to pumping at the setting time of 1, 1+T pos ', …, 1+(n-1)T pos '. If two units (currently usually two units) in each power station at each planned point are switched to pumping, the first unit can be sequentially switched to pumping at the setting time of 1, 1+T pos ' / 2, …, 1+(n-1)T pos ' / 2 minutes, and the second unit can be sequentially switched to pumping at the setting time of 1+nT pos' / 2、1+(n+1)T pos ' / 2、……、1+(2n-1)T pos ' / 2 minutes set time to start pumping.

[0093] (1.2.4) Pumping Shutdown: The pumping shutdown setting time specifies the start time of the shutdown process triggered by the unit from pumping operation, and the pumping shutdown setting time interval:

[0094]

[0095] Among them, T pdi This refers to the time it takes for unit i of the pumped-storage power station to go from pumping steady state to disconnection. For ease of implementation, T... pod After calculation, round down to the nearest half-minute to get T. pod When there are many pumped storage power stations in the group, T pod When the calculated value is less than max(Tpd1, Tpd2, ..., Tpdn), a separate pumped storage power station group needs to be set up.

[0096] If only one unit at each power station is switched to pumping at each planned point, then the pumping can be switched to 1, 1+T sequentially. pod '、……、1+(n-1)T pod The pumping and shutdown process is scheduled for 1 minute. If each power station has two units scheduled for pumping and shutdown at each planned point, the first unit can be started sequentially at 1, 1+T. pod ' / 2、……、1+(n-1)T pod The pumping unit will be switched to a stop after a 2-minute set time. The second unit can be switched to a stop unit sequentially by pressing 1+nT. pod ' / 2、1+(n+1)T pod ' / 2、……、1+(2n-1)T pod The pumping cycle is set to stop within a 2-minute interval.

[0097] (2) When the pumped storage power station is operating normally for peak shaving and is within the adjustable range of the power generation start / stop load, the total load of the power station will rise and fall according to the slope of the 96-point planned curve to smooth the power change of the pumped storage power station.

[0098] (2.1)Reference Figure 2 As shown, Figure 2 The medium load setpoint is from (0, P) c ) to (15, P n The straight line represents the load, and the curve consisting of three segments represents the actual load. Tb is the unit's grid connection time (also known as the initial time). When the first unit of the pumped storage power station starts generating electricity, it first starts up and connects to the grid according to the set time, bringing the load up to the minimum stable load P. h Then, the load is increased to the target value according to the variable load slope determined by the power difference between the two planned points. Load increase rate (MW / min) = (Pn - P c ) / 15, where P n is the next planned point target load, P c is the initial load of the previous planned point, Figure 2 P c is greater than 0. When Figure 2 represents the first unit, P c is equal to 0. If the load set value P si is less than P h + P c , the minimum stable operation load P h is maintained until the load set value is increased at the rate to be greater than or equal to P h + P c and the output is increased again.

[0099] (2.2) When the pumped storage power station non-first unit generates power and starts, regardless of whether the first unit of the planned point starts according to the setting time, if the load of the newly started unit is increased to the minimum stable operation load P h and the load of the running unit at that time is greater than the load set value curve with the rate, the running unit needs to cooperate to reduce the output, so that the actual power of the whole station is equal to the load set value with the rate.

[0100] (2.3) When the power grid appears abnormal working conditions and needs to quickly start and stop the pumped storage power station, the real-time load instruction is issued through the emergency support instruction at this time, and the pumped storage unit increases and decreases the load at the maximum rate, without the need to smooth the output according to the variable load rate of the peak shaving start and stop mode.

[0101] (3) The method of frequency reverse locking is adopted to suspend the start / stop and load increase / decrease when the frequency deviation is greater than the setting value.

[0102] (3.1) When the pumped storage unit executes the power generation start or water pumping stop process, if the frequency deviation (rated frequency-real-time frequency) is less than the negative start / stop setting value, the execution of the process is suspended until the frequency deviation is less than the setting value, and then the start / stop is continued;

[0103] (3.2) When the pumped storage unit executes the power generation stop or water pumping start process, if the frequency deviation is greater than the positive start / stop setting value, the execution of the process is suspended until the frequency deviation is less than the setting value, and then the start / stop is continued;

[0104] (3.3) When the pumped storage unit is in the power generation start process and the load reaches the target value before the minimum stable operation load, if the frequency deviation is less than the negative load increase setting value, the current load is maintained until the frequency deviation is restored and the load increase is continued;

[0105] (3.4) When the pumped storage unit is in the process of generating and shutting down, if the frequency deviation is greater than the positive load shedding setting value before the load reaches the minimum stable operation load, the current load is kept unchanged until the frequency deviation is restored and then the load shedding is continued.

[0106] To sum up, the regional power grid pumped storage power station group start-stop scheduling optimization method provided by the application adopts the method of grouping pumped storage power stations by province and city and adjusting the start-stop time of peak shifting, and the pumped storage unit smoothly increases / decreases the load within the adjustable range, and combines the limitation of real-time frequency on start-stop and load increase / decrease to realize flexible and flexible control of the pumped storage unit, enhance the anti-disturbance ability of the power grid, greatly reduce the impact of pumped storage concentration start-stop on power grid power fluctuation, meet the diversified regulation demand of load peak shaving and new energy fluctuation suppression, and improve the scientific scheduling level of pumped storage power stations.

[0107] The above is only a specific embodiment of the application, but the protection scope of the application is not limited thereto, and any person skilled in the art can easily think of various equivalent modifications or replacements within the technical range disclosed by the application, and these modifications or replacements should be covered within the protection scope of the application. Therefore, the protection scope of the application should be subject to the protection scope of the claims.

Claims

1. A regional power grid pumped storage power station group start-stop machine dispatching optimization method, characterized in that, The method comprises the following steps: Step 1, setting the setting time for each working condition of each unit in all pumped storage power stations in the regional power grid, so that the total number of units simultaneously generating electricity, starting and stopping at the same time and pumping water is less than a preset threshold; wherein the setting time represents the starting and stopping time; Step 2, when the pumped storage power station is normally peak-shifting starting and stopping in the generating condition, and is in the adjustable load range, the total load of the power station is raised and lowered according to the slope of the load uniform speed between adjacent two planned points and the setting time, so as to smooth the power change of the pumped storage power station; Step 3, when the frequency deviation of the regional power grid is greater than a preset setting value, the frequency reverse locking method is used to suspend the generating electricity starting and stopping, the pumping water starting and stopping and the load raising and lowering of the pumped storage unit which will cause the frequency deviation to expand; The step 1 specifically comprises the following steps: Step 1.1, grouping all pumped storage power stations in the regional power grid according to the province and city control area; Step 1.2, setting the setting time for each group of power stations, and using different setting times for different starting and stopping conditions, which specifically comprises the following steps: Step 1.2.1, setting the setting time for generating electricity starting: only the first unit of each power station in each one o'clock planned point sets the starting setting time; Step 1.2.2, setting the setting time for generating electricity stopping: only the last unit of each power station sets the setting time for generating electricity stopping; Step 1.2.3, setting the setting time for pumping water starting: the pumping water starting unit is driven to the pumping water and phase modulation working condition in advance by the static frequency converter or back-to-back, and the setting time for pumping water starting is the time when the unit is switched from the pumping water and phase modulation working condition to the pumping water working condition; Step 1.2.4, setting the setting time for pumping water stopping: the setting time for pumping water stopping is the starting time when the unit triggers the stopping process from the pumping water working condition.

2. The method of claim 1, wherein the method further comprises: The step 1.2.1 specifically comprises: Defining that there are n pumped storage power stations in the same province and city group, and the allocation principle of the setting time is: Firstly, the generating electricity starting setting time interval is obtained: ； wherein, is the duration from the start-up order to the grid-connection of the first unit of the pumped storage power plant, is the duration from the grid-connection to the rated power of the first unit of the pumped storage power plant, is the duration from the start-up order to the grid-connection of the first unit of the pumped storage power plant, is the duration from the grid-connection to the rated power of the first unit of the pumped storage power plant, Then, the calculated Tgos' is obtained by rounding down Tgos in half-minute units. then the first unit in each planning point of each power station is arranged according to The setting time of power generation start is arranged in turn according to 1, 1+Tgos', …, 1+(n-1)Tgos' minutes in the order from small to large.​ 3. The method of claim 2, wherein the method further comprises: When multiple units in the same power plant at the same planning point are started, the start-up time of the units other than the first unit is obtained according to the start-up time of the first unit and the minimum stable load value P h , wherein the start-up time of the units other than the first unit is obtained by the following method: According to the deviation of the actual load rising curve of the power station and the slope between the two planning points, the sum P of the absolute values of the power deviations is obtained e , and according to the minimum value of P e , the start-up time point of the remaining units is obtained where P e = ; is the total power generated by the power plant at time i. Pset(i) = Pset(i-1) + (Pmax - Pmin) / m * T c Pset(i) = Pset(i-1) + (Pmax - Pmin) / m * T n c Pset(i) = Pset(i-1) + (Pmax - Pmin) / m * T i ​​ P n P is the target load for the next plan point c m is the initial load for the start of the plan point, m is the number of samples calculated within 15 minutes of a plan point, T i is the ith sample time point.

4. The method of claim 1, wherein, The step 1.2.2 specifically comprises: The generating electricity stopping setting interval time is obtained by using the following formula: ； wherein pumped storage power plant the last unit of the pumped storage power plant from the minimum stable operating load P h to the shortest duration of the decoupling, the calculated is rounded down to the nearest half minute to obtain T god ’ ; Then the last unit of each power station is in turn according to 7, 7+T god ’ , …, 7+(n-1)T god ’ The setting time of 7 minutes of power generation shutdown.

5. The method of claim 1, wherein, The step 1.2.3 specifically comprises: The pumping water starting setting interval time is obtained by using the following formula: ； Wherein, pumped storage power station The unit of the pumped storage power station is switched from pumped phase modulation to pumping for the duration, and the calculated T is obtained by rounding down the calculated T to the nearest half minute pos ’ ; If only one unit is pumped at each planning point of each power station, then the units are pumped in turn according to 1, 1+T, …, 1+(n-1)T pos ’ , …, 1+(n-1)T pos ’ with a setting time of 1, 1+T, …, 1+(n-1)T minutes.

6. The method of claim 5, wherein the method further comprises: If each power station has two units to be pumped at each planning point, the first unit is pumped in turn at 1, 1+T pos ’ / 2, …, 1+(n-1)T pos ’ / 2 minutes of setting time, and the second unit is pumped in turn at 1+nT pos ’ / 2, 1+(n+1)T pos ’ / 2, …, 1+(2n-1)T pos ’ / 2 minutes of setting time.

7. The method of claim 1, wherein, The step 1.2.4 specifically comprises: The pumping water stopping setting time interval is obtained by using the following formula: ； Wherein, pumped storage power station The time from the pumped steady state to the disconnection of the unit of the pumped storage power station, the calculated T is obtained by rounding down the calculated T to the nearest half minute pod ’ ; If only one unit in each power station at each planning point is pumped storage, then in turn, 1, 1+T pod ’ , …, 1+(n-1)T pod ’ minute setting time pumped storage to stop; if two units in each power station at each planning point are pumped storage to stop, then the first unit in turn, 1, 1+T pod ’ / 2, …, 1+(n-1)T pod ’ / 2 minute setting time pumped storage to stop, the second unit in turn, 1+nT pod ’ / 2, 1+(n+1)T pod ’ / 2, …, 1+(2n-1)T pod ’ / 2 minute setting time pumped storage to stop.

8. The method of claim 1, wherein, The step 2 specifically comprises: Step 2.1, when the first unit of pumped storage power station generates electricity, first start grid connection according to setting time, and load to the minimum stable load P h , then increase the load to the target value according to the load change slope determined by the power difference between the previous and next plan points; if the unit reaches the minimum stable load, the load setting value P si is less than P h + P c , then maintain the minimum stable operating load P h unchanged until the load setting value increases at a rate greater than or equal to P h + P c , then increase the output, where P n is the target load of the next plan point, and P c is the initial load of the plan point before starting. Step 2.2, when the non-first unit of the pumped storage power station generates power and starts, whether the first unit is planned to start according to the setting time, if the newly started unit increases the load to the minimum stable operation load P h When the load of the running unit at the moment is greater than the set load value corresponding to the load setting value curve of the current power station with the speed rate, the running unit needs to cooperate to reduce the output, so that the actual generated power of the whole station is equal to the load setting value with the speed rate. Step 2.3, when the power grid appears abnormal working condition and needs the pumped storage power station to quickly start and stop, the real-time load instruction is issued in the form of emergency support instruction, at this time the pumped storage unit raises and lowers the load at the maximum rate without needing to change the load rate to smooth the output according to the peak-shifting starting and stopping mode.

9. The method of claim 1, wherein, The step 3 specifically comprises: Step 3.1, when the pumped storage unit executes the generating electricity starting or pumping water stopping process, if the frequency deviation is less than the negative starting and stopping setting value, the execution of the generating electricity starting or pumping water stopping process is suspended, and after the frequency deviation is less than the setting value, the starting and stopping is continued, wherein the frequency deviation = the rated frequency of the power grid - the real-time frequency of the power grid; Step 3.2, when the pumped storage unit executes the generating electricity stopping or pumping water starting process, if the frequency deviation is greater than the positive starting and stopping setting value, the execution of the generating electricity stopping or pumping water starting process is suspended, and after the frequency deviation is less than the setting value, the starting and stopping is continued. Step 3.3, when the pumped storage unit is in the process of starting generation and the load is greater than the minimum stable operation load and reaches the target value, if the frequency deviation is less than the negative load increase setting value, the current load is kept unchanged until the frequency deviation is restored and then the load is increased; Step 3.4, when the pumped storage unit is in the process of stopping generation and the load reaches the minimum stable operation load, if the frequency deviation is greater than the positive load decrease setting value, the current load is kept unchanged until the frequency deviation is restored and then the load is decreased.

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