Method for regulating and controlling safe and stable section operation of wind-fire bundling and sending-out system and related device

Abstract

The invention provides a safe and stable section operation regulation and control method for a wind-thermal bundled delivery system and a related device, and provides a piecewise linear section pre-control method by analyzing system stability conditions in different operation modes according to off-line simulation calculation of massive operation modes. And when the current thermal power of the wind-thermal bundled sending-out system is smaller than or equal to the thermal power critical value, the constraint on the wind power is released, so that the output of the wind turbine generator is not constrained by the section pre-control requirement. And when the current thermal power is greater than the thermal power critical value, pre-controlling the wind-thermal bundled delivery system so as to adjust the operation power of each unit in the wind-thermal bundled delivery system to be in the safe and stable operation control domain to ensure that the N-1 transient state delivered by the system is stable. Therefore, the intrinsic safety of the system net rack under the background of large-scale new energy production can be ensured, and meanwhile, the problem that the regional sending-out capability is limited due to an excessively harsh N-1 section pre-control strategy is avoided.

Description

Technical Field

[0001] The present application relates to the technical field of power system control, and in particular to a method and related device for controlling the safe and stable cross-section operation of a wind-fire bundled delivery system. Background Art

[0002] With the continuous commissioning of offshore wind turbines, the southern region will see a multi-regional, large-scale offshore wind power generation system, combined with nearby conventional power sources, be integrated into the receiving grid to supply power to load centers. As the grid-connected capacity of wind power and conventional turbines increases, regional stability issues are shifting from being primarily thermal stability issues to a complex interplay of power angle and thermal stability issues. Furthermore, the number of system power angle instability failures is increasing after N-1 single-line faults trip the regional transmission channel. The Power System Safety and Stability Guidelines (GB38755-2019) stipulate that under normal conditions, the system should maintain stable operation and normal grid power supply without initiating stability control measures after a single fault disturbance. However, for three-phase faults on AC transmission lines of power sources (including conventional power plants and renewable energy stations), single-pole faults on DC transmission lines of power sources, or faults or unfaulted disconnections of a single higher-voltage line in a two-level electromagnetic ring network, N-1 emergency power control tripping or rapid power output reduction measures are permitted when necessary.

[0003] For N-1 faults in the bundled wind and thermal transmission area, post-fault N-1 emergency power control can be implemented to remove wind and thermal power units to ensure system stability, or preemptive regional transmission section control measures can be implemented to ensure system stability. However, implementing N-1 emergency power control will increase the power limit of the regional transmission section, increasing the number of emergency power control measures required after severe N-2 faults in the area, which can easily cause secondary frequency stability issues in the system and, in severe cases, trigger the system's third line of defense.

[0004] Since thermal power units and wind power units have different impact mechanisms on regional transmission transient stability problems, the system transmission stability limits are different under different wind power and thermal power ratios. The current preventive control measures are based on robustness. For the same transmission section in the region, the safe and stable section control quantity is determined based on the wind-to-fire transmission ratio scenario with the most serious stability problem. This can easily lead to larger power constraints in scenarios with the same transmission section (under the wind-to-fire transmission ratio scenario with better stability).

[0005] It can be seen that the existing N-1 section preventive control measures will cause the problem of limited regional transmission capacity. Summary of the Invention

[0006] The purpose of this application is to solve at least one of the above-mentioned technical deficiencies, especially the technical deficiency of limited regional transmission capacity in the prior art.

[0007] In a first aspect, an embodiment of the present application provides a method for controlling safe and stable cross-section operation of a wind and fire bundle delivery system, the method comprising:

[0008] Obtain an equivalent model of the air-fire bundle delivery system;

[0009] A transient simulation calculation is performed based on the equivalent model to obtain multiple sets of stable boundary powers; wherein the stable boundary powers are the critical thermal power and critical wind power when the wind-thermal bundled transmission system is in a transient power angle stable boundary scenario;

[0010] Determine a thermal power critical value based on the multiple groups of stable boundary powers; wherein the thermal power critical value is the maximum thermal power when the wind power is not limited;

[0011] In response to the current thermal power of the wind-fire bundle delivery system obtained, if the current thermal power power is less than or equal to the thermal power critical value, the wind turbine units of the wind-fire bundle delivery system are not pre-controlled; otherwise, the wind-fire bundle delivery system is pre-controlled to adjust the total output power of the wind-fire bundle delivery system to less than or equal to a predetermined total delivery section control value.

[0012] In some embodiments, the equivalent model is:

[0013]

[0014] Where, is the self-impedance of the thermal power unit in the wind-fire bundled delivery system, is the mutual impedance between the thermal power unit and the receiving system, is the equivalent negative impedance model of the wind turbine generator set; is the equivalent reactance of the first transmission channel, where the first transmission channel is the transmission channel from the thermal power generation unit to the wind turbine generation grid connection point; is the equivalent reactance of the second transmission channel, where the second transmission channel is the transmission channel from the wind turbine grid connection point to the AC power grid; is the imaginary unit, is the current active power of the wind turbine, is the current reactive power of the wind turbine, is the grid connection point voltage of the wind turbine generator system.

[0015] In some embodiments, performing transient simulation calculations based on the equivalent model to obtain multiple sets of stable boundary powers includes:

[0016] Constructing a transient stability margin model based on the equivalent model, the system acceleration model and the system deceleration model of the wind-fire bundling system;

[0017] Analyzing and calculating the transient stability margin model according to a preset stability margin value to obtain multiple groups of initial operating powers;

[0018] For each group of the initial operating power, a transient simulation calculation is performed based on the wind power and thermal power in the group of initial operating power to obtain a system stability result, and the group of initial operating power is corrected based on the system stability result until the preset end condition is met and the stable boundary power is obtained.

[0019] In some embodiments, the step of correcting the set of initial operating powers according to the system stability result until a preset termination condition is satisfied and the stable boundary power is obtained includes:

[0020] If the system stability result is transient power angle instability, the thermal power in the initial operating power of the group is maintained unchanged, and the wind power in the initial operating power of the group is reduced until the transient power angle is stable, thereby obtaining the stable boundary power; wherein the critical thermal power is the thermal power in the initial operating power of the group, and the critical wind power is the minimum wind power when the transient power angle is stable;

[0021] If the system stability result is that the transient power angle is stable, the thermal power in the initial operating power of the group is kept unchanged, and the wind power in the initial operating power of the group is increased until the transient power angle becomes unstable, thereby obtaining the stable boundary power; wherein, the critical thermal power is the thermal power in the initial operating power of the group, and the critical wind power is the maximum wind power under the condition of transient power angle stability.

[0022] In some embodiments, the transient stability margin model is:

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029] Where, is the transient stability margin model, is the system deceleration model, is the system acceleration model, is the fault removal angle, is the critical power angle of the thermal power unit, is the power angle, is the initial power angle of the thermal power unit; The self-impedance of the thermal power unit in the wind-fire bundled delivery system before the fault is cut off; The mutual impedance between the thermal power unit and the receiving system before the fault is cleared; and Determined based on the equivalent model; is the output voltage of the thermal power unit, is the voltage of the AC grid; is the self-impedance angle of the thermal power unit before the fault is cleared; is the mutual impedance angle of the thermal power unit before the fault is cleared; is the input mechanical power of the thermal power unit, is the rated angular frequency of the wind and fire bundle delivery system, is the synchronous machine inertia time constant, The duration from the time the fault occurs to the time the fault is cleared; is the self-impedance of the thermal power unit after the fault is cleared; The mutual impedance between the thermal power unit and the receiving system after the fault is cleared; is the self-impedance angle of the thermal power unit after the fault is cleared; It is the mutual impedance angle of the thermal power unit after the fault is cleared.

[0030] In some embodiments, the pre-controlling of the air-fire baling and delivery system includes:

[0031] According to the predetermined total transmission section control value, the actual thermal power and actual wind power of the wind-fire bundled transmission system are adjusted so that the sum of the adjusted actual thermal power and actual wind power is less than or equal to the total transmission section control value.

[0032] In some embodiments, the step of determining the control value of the total amount of the delivery section includes:

[0033] A target boundary power corresponding to a maximum critical thermal power power is determined in the multiple groups of stable boundary powers, and the sum of the critical thermal power power and the critical wind power in the target boundary power is used as the total transmission section control value.

[0034] In a second aspect, an embodiment of the present application provides a device for controlling safe and stable cross-section operation of a wind and fire bundle delivery system, the device comprising:

[0035] Equivalent model building module, used to obtain the equivalent model of the wind and fire bundle delivery system;

[0036] a simulation calculation module, configured to perform transient simulation calculations based on the equivalent model to obtain multiple sets of stable boundary powers; wherein the stable boundary powers are critical thermal power and critical wind power when the wind-thermal bundled delivery system is in a transient power angle stable boundary scenario;

[0037] a thermal power critical value determination module, configured to determine a thermal power critical value based on the multiple groups of stable boundary powers; wherein the thermal power critical value is the maximum thermal power when wind power is not limited;

[0038] a control module, configured to respond to the acquired current thermal power of the wind-fire bundle delivery system, and if the current thermal power is less than or equal to the thermal power critical value, not pre-control the wind turbine units of the wind-fire bundle delivery system; otherwise, pre-control the wind-fire bundle delivery system to adjust the total output power of the wind-fire bundle delivery system to be less than or equal to a predetermined total delivery section control value.

[0039] In a third aspect, an embodiment of the present application provides a storage medium storing computer-readable instructions. When the computer-readable instructions are executed by one or more processors, the one or more processors execute the steps of the method for controlling the safe and stable section operation of the wind and fire bundling delivery system described in any of the above embodiments.

[0040] In a fourth aspect, an embodiment of the present application provides a computer device, the computer device comprising: one or more processors, and a memory;

[0041] The memory stores computer-readable instructions, and when the computer-readable instructions are executed by the one or more processors, the steps of the method for controlling safe and stable section operation of the wind and fire bundling delivery system described in any of the above embodiments are executed.

[0042] In the safe and stable section operation control method and related device of the wind-fire bundled delivery system provided in some embodiments of the present application, a piecewise linear N-1 stable section preventive control scheme for different wind / fire output states is proposed. This application analyzes the system stability under different operating modes based on offline simulation calculations of massive operating modes and proposes a piecewise linear section pre-control method. When the current thermal power power of the wind-fire bundled delivery system is less than or equal to the thermal power critical value, the constraints on wind power are released so that the output of the wind turbine unit is not constrained by the section pre-control requirements. When the current thermal power power is greater than the thermal power critical value, the wind-fire bundled delivery system is pre-controlled to adjust the operating power of each unit in the wind-fire bundled delivery system within the safe and stable operation control domain to ensure the N-1 transient stability of the system output. In this way, the inherent safety of the system grid can be ensured in the context of large-scale new energy production, while avoiding the problem of limited regional delivery capacity caused by overly stringent N-1 section pre-control strategies. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0044] Figure 1 A flow chart of a method for controlling safe and stable cross-section operation of a wind and fire bundle delivery system in some embodiments;

[0045] Figure 2 One of the system structure diagrams of the air-fire bundle delivery system in some embodiments;

[0046] Figure 3 An equivalent model of an air-fire bundle delivery system in some embodiments;

[0047] Figure 4 A schematic diagram of transient simulation results in some embodiments;

[0048] Figure 5 is a flowchart of a power calibration step in some embodiments;

[0049] Figure 6 A schematic diagram of a thermal power critical value in some embodiments;

[0050] Figure 7 A schematic diagram of the pre-control strategy of the present application in some embodiments;

[0051] Figure 8 This is a second system structure diagram of the air-fire bundle delivery system in some embodiments;

[0052] Figure 9 Schematic diagram comparing the pre-control strategy provided by the present application with the prior art in some embodiments;

[0053] Figure 10 A schematic diagram of the structure of a safe and stable cross-section operation control device for a wind and fire bundle delivery system in some embodiments;

[0054] Figure 11 This is a schematic diagram of the structure of a computer device in some embodiments. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0056] In some embodiments, as Figure 1 As shown, the present application provides a method for controlling the safe and stable cross-section operation of a wind and fire bundle delivery system, which specifically includes the following steps:

[0057] S102: Obtain an equivalent model of the air-fire bundling and delivery system.

[0058] A wind-thermal bundled transmission system refers to a power system configuration that transmits the combined output of thermal and wind turbines to the AC grid. Because a wind-thermal bundled transmission system includes at least one thermal generator, at least one wind turbine, and a transmission network to which the generators are connected, and the transmission network may include any one or any combination of transmission lines, transformers, and reactive power compensation devices, the system structure is complex. Therefore, to facilitate calculation and analysis, the wind-thermal bundled transmission system can be simplified and equivalently evaluated through methods such as power system analysis. This allows it to be converted into an equivalent circuit or mathematical model with a relatively simple structure that is easy to calculate and analyze, thereby obtaining an equivalent model.

[0059] Specifically, in actual application scenarios, a wind-fired bundled transmission system usually has multiple thermal power units and multiple wind farms. Among them, since the thermal power units are all connected to the grid via the same bus, multiple thermal power units can be regarded as one synchronous unit. Ignoring the internal wiring of the wind farm station, multiple wind farms can be regarded as one wind turbine unit. The typical system structure of the wind-fired bundled transmission system can be as follows: Figure 2 As shown in Figure 1, renewable energy (i.e., wind turbines) are connected to the grid via AC integration and the same busbar as traditional generators (i.e., thermal power plants). The analysis uses a second-order classical model for the traditional generators, and the role of synchronous generator speed regulators is not considered during transients.

[0060] Considering that the renewable energy uses maximum power tracking control to generate active power under normal operation, it can be equivalent to a negative resistance model. During a fault, according to low voltage ride-through control, the renewable energy generates less active power during the transient process and generates a certain amount of reactive power, which can be equivalent to a negative resistance and negative reactance model. Therefore, the renewable energy can be expressed as a negative impedance Z w Model, that is:

[0061]

[0062] Where, is the equivalent impedance of the wind turbine, is the active power of the wind turbine, is the reactive power of the wind turbine, is the grid connection point voltage of the wind turbine, is the imaginary unit and * is the complex conjugate.

[0063] Based on the above assumptions, the regional new energy unit AC transmission system can be simplified equivalently. The simplified equivalent model can be as follows: Figure 3 As shown. Among them, is the transient potential of the thermal power unit, is the voltage of the AC grid. is the transient impedance of the thermal power unit, is the transformer equivalent impedance, is the first line impedance, is the second line impedance, is the third line impedance, - is the equivalent negative impedance of the wind turbine.

[0064] It is deduced that before the integration of new energy, the electromagnetic power-power angle equation of the thermal power unit can be expressed as:

[0065]

[0066] Where, is the electromagnetic power of the thermal power unit, is the transient potential of the thermal power unit, is the voltage of the AC grid; is the equivalent reactance of the first transmission channel, which is the transmission channel from the thermal power generation unit to the wind turbine generator grid connection point; is the equivalent reactance of the second transmission channel, which is the transmission channel from the wind turbine grid connection point to the AC grid. It is the angle between the potential of the thermal power unit and the receiving system vector.

[0067] After considering the access of new energy, according to Figure 2 and Figure 3 The loop current equation can be written and solved to obtain the loop current The expression is:

[0068]

[0069] Where, is the voltage phasor of the thermal power unit, is the voltage phasor of the AC grid.

[0070] definition is the self-impedance of the thermal power unit, is the mutual impedance between the thermal power unit and the receiving system, then the self-impedance and mutual impedance The expression can be:

[0071]

[0072] Where, is the self-impedance angle of the thermal power unit, is the mutual impedance angle of the thermal power unit.

[0073] The analysis shows that the electromagnetic power-power angle equation of the traditional units in the region after considering the integration of new energy can be expressed as follows:

[0074]

[0075] Where, is the electromagnetic power of the thermal power unit.

[0076] Combining the above formulas, we can further obtain the self-impedance , mutual impedance Relationship with new energy power:

[0077]

[0078] Where, The self-impedance of the thermal power unit in the wind-thermal bundled transmission system, is the mutual impedance between the thermal power unit and the receiving system, is the equivalent negative impedance model of the wind turbine; is the equivalent reactance of the first transmission channel, which is the transmission channel from the thermal power generation unit to the wind turbine generator grid connection point; is the equivalent reactance of the second transmission channel, which is the transmission channel from the wind turbine grid connection point to the AC grid; is the imaginary unit, is the current active power of the wind turbine, is the current reactive power of the wind turbine, is the grid connection point voltage of the wind turbine.

[0079] Thus, an equivalent model of the air-fire bundle delivery system can be obtained.

[0080] S104: Perform transient simulation calculations based on the equivalent model to obtain multiple sets of stable boundary powers; wherein the stable boundary powers are the critical thermal power and critical wind power when the wind-thermal bundled transmission system is in a transient power angle stable boundary scenario.

[0081] Critical thermal power refers to the output power of a thermal generator unit when the wind-thermal bundled transmission system is at the transient power angle boundary stability scenario, while critical wind power refers to the output power of a wind turbine unit when the wind-thermal bundled transmission system is at the transient power angle boundary stability scenario. The transient power angle boundary stability scenario refers to a scenario where even slight adjustments to thermal power and / or wind power can cause the wind-thermal bundled transmission system power angle to become unstable.

[0082] In this embodiment, transient simulation can be performed based on the equivalent model of the wind-fire bundled delivery system to obtain multiple sets of power in the transient stability scenario and multiple sets of power in the power angle instability scenario, and the stable boundary power is obtained accordingly.

[0083] In some embodiments, S104 may include the following steps:

[0084] Step A1: Construct a transient stability margin model based on the equivalent model, the system acceleration model and the system deceleration model of the wind-fire bundling system;

[0085] Step A3: Analyze and calculate the transient stability margin model according to the preset stability margin value to obtain multiple groups of initial operating powers;

[0086] Step A5: For each group of initial operating power, perform transient simulation calculations based on the wind power and thermal power in the group of initial operating power to obtain a system stability result, and correct the group of initial operating power based on the system stability result until the preset end condition is met and the stable boundary power is obtained.

[0087] Among them, the system acceleration model is used to measure the acceleration caused by unit failure in the wind-fire bundled transmission system, and the system deceleration model is used to measure the deceleration when the active power can be restored after the failure of the new energy. For different wind-fire bundled transmission power combinations, the transient stability margin considering the difference between the deceleration area and the acceleration area as the regional transmission can be calculated based on the system acceleration model and the system deceleration model, and the transient stability margin model MS is obtained. That is, .

[0088] Furthermore, in some examples, for the N-1 fault of the wind-fire bundle delivery system, the impact caused by the three-phase grounding fault at the grid connection point of the traditional unit is the most serious. During the fault period, the electromagnetic power output by the traditional unit is zero. Considering the fault sequence duration of , then the system acceleration model is:

[0089]

[0090] Where, is the system acceleration area, is the input mechanical power of the thermal power unit, is the fault removal angle, is the initial power angle of the thermal power unit, is the rated angular frequency of the wind and fire bundle delivery system, is the inertia time constant of the synchronous machine.

[0091] Where, the initial power angle They are the electromagnetic power curve and mechanical power curve before the fault Solve and obtain the fault removal power angle It can be calculated based on the generator rotor motion equation:

[0092]

[0093] Where, To eliminate the self-impedance of the thermal power units in the wind-heat bundled transmission system before the fault occurs; The mutual impedance between the thermal power unit and the receiving system before the fault is cleared; is the output voltage of the thermal power unit, is the voltage of the AC grid; is the self-impedance angle of the thermal power unit before the fault is cleared; It is the mutual impedance angle of the thermal power unit before the fault is cleared.

[0094] For the N-1 fault in the wind-thermal bundled transmission area, when new energy is connected, considering that active power is immediately restored after the new energy failure, the deceleration area of ​​the output system is:

[0095]

[0096] Where, is the critical power angle of the thermal power unit.

[0097] Where, critical power angle The electromagnetic power curve and mechanical power after the fault can be Solve to get:

[0098]

[0099] Where, It is the self-impedance of the thermal power unit after the fault is cleared; It is the mutual impedance between the thermal power unit and the receiving system after the fault is cleared; is the self-impedance angle of the thermal power unit after the fault is cleared; It is the mutual impedance angle of the thermal power unit after the fault is cleared.

[0100] To ensure that the system can maintain transient stability after a fault, the deceleration area of ​​the system after the fault must be larger than the acceleration area caused by the fault, which can be expressed as:

[0101]

[0102] Based on different wind-fire bundled power transmission combinations, the transient stability margin of regional transmission considering the difference between the deceleration area and the acceleration area can be calculated. If MS is greater than zero, the region is transiently stable; if MS is less than zero, the region is transiently unstable. Therefore, the transient stability margin model can be analyzed and calculated using the preset stability margin value, and the transient stability operation domain of the wind-fire bundled delivery system under the N-1 fault scenario can be obtained. Based on the transient stability operation domain, multiple groups of stable boundary powers can be obtained.

[0103] It is understood that the specific value of the stability margin value can be determined according to the actual situation. For example, the stability margin value can be zero, that is, the present application can use the operating points near the transient stability margin MS=0 as multiple sets of initial operating power, and perform electromechanical transient simulation verification on the multiple sets of initial operating power to obtain the stable boundary power. In this case, the transient simulation calculation results can be as follows Figure 4 shown.

[0104] For each group of initial operating power, the present application can perform transient simulation based on the thermal power and wind power in the group of initial operating power, and perform power correction based on the system stability results obtained from the transient simulation, so that the corrected operating power can accurately reflect the unit power of the wind-fire bundled transmission system under the transient power angle stability boundary scenario.

[0105] In some examples, such as Figure 5 As shown, the initial operating power of the group is corrected according to the system stability result until the preset end condition is met and the stable boundary power is obtained, including:

[0106] Step A51: If the system stability result is transient power angle instability, the thermal power in the initial operating power group is maintained unchanged, and the wind power in the initial operating power group is reduced until the transient power angle is stable, thereby obtaining the stable boundary power; wherein the critical thermal power is the thermal power in the initial operating power group, and the critical wind power is the minimum wind power when the transient power angle is stable;

[0107] Step A53: If the system stability result is that the transient power angle is stable, the thermal power in the initial operating power of the group is kept unchanged, and the wind power in the initial operating power of the group is increased until the transient power angle becomes unstable, thereby obtaining the stable boundary power; wherein, the critical thermal power is the thermal power in the initial operating power of the group, and the critical wind power is the maximum wind power under the condition of transient power angle stability.

[0108] In this example, during the calibration process, if the system stability result indicates transient power angle stability, the wind turbine output is increased until the system transient power angle becomes unstable. The system operating point before the transient instability is used as the stability boundary operating point, thereby obtaining the stability boundary power. If the system stability result indicates transient power angle instability, the wind turbine output is reduced until the system transient power angle becomes stable. This system operating point is used as the stability boundary operating point, thereby obtaining the stability boundary power.

[0109] For example, in the running scenario analysis, P (P H , P W ) represents the system operation scenario, where P H Indicates the output power of thermal power unit, unit MW, P W Indicates the output power of the wind turbine, in MW.

[0110] By performing electromechanical transient simulation verification at operating points near the transient stability margin MS = 0, the stability boundary is simulated and corrected. If the system is stable during electromechanical simulation calculations at operating points near the transient stability margin MS = 0, the wind power output is increased by 100 MW until the system transient power angle becomes unstable. The system operating point before transient instability is considered the stability boundary operating point. If the system power angle becomes unstable during electromechanical simulation calculations at operating points near the transient stability margin MS = 0, the wind power output is reduced by 100 MW until the system transient power angle stabilizes. This system operating point is considered the stability boundary operating point.

[0111] S106: Determine a thermal power critical value based on multiple groups of stable boundary powers; wherein the thermal power critical value is the maximum thermal power when wind power is not limited.

[0112] In this step, if Figure 6 As shown in the figure, the maximum thermal power of wind turbines without operating power restrictions is determined in the safety and stability domain of the wind-thermal bundled transmission system, and the thermal power critical value P is obtained. HCritical .

[0113] S108: In response to the current thermal power of the wind-fire bundled delivery system, if the current thermal power is less than or equal to the thermal power critical value, the wind turbine units of the wind-fire bundled delivery system are not pre-controlled; otherwise, the wind-fire bundled delivery system is pre-controlled to adjust the total output power of the wind-fire bundled delivery system to less than or equal to a predetermined total delivery section control value.

[0114] Specifically, the existing section control takes the overall section power of the wind and fire bundle delivery area as the control object, as shown in P H +P W ≤P set , where P H is the output power of the thermal power unit, P W is the output power of the wind turbine, Pset This method is simple to operate, but due to the different system stability characteristics under different wind power / thermal power operating conditions, that is, when the proportion of wind power generation is high, the system section transmission transient stability limit is higher. In order to release the power transmission capacity of the region under different wind power / thermal power operating conditions, a piecewise linear section pre-control method is proposed.

[0115] In this step, the pre-control can be performed by using the piecewise linear section pre-control strategy. H ≤P HCritical When the wind power constraints can be released, that is, the wind turbine output is not subject to the section pre-control requirements; and when the thermal power output P H >P HCritical When the wind and fire bundle delivery system is pre-controlled according to a preset pre-control strategy, the total output power of the wind and fire bundle delivery system can be adjusted to be less than or equal to the predetermined total output section control value. For example, the present application can reduce either the thermal power or the wind power of the wind and fire bundle delivery system to reduce the total output power of the system to a power value less than or equal to the total output section control value.

[0116] In some examples, pre-controlling the air and fire bale delivery system may include:

[0117] According to the predetermined total transmission section control value, the actual thermal power and actual wind power of the wind-thermal bundled transmission system are adjusted so that the sum of the adjusted actual thermal power and actual wind power is less than or equal to the total transmission section control value.

[0118] In this example, when the thermal power unit output P H >P HCritical When the total amount of the delivery section is used as a constraint, that is, P H +P W ≤P set For control requirements. That is:

[0119]

[0120] Where, It is the total control value of the sent section.

[0121] Furthermore, in some examples, the step of determining the total control value of the transmission section includes: determining the target boundary power corresponding to the maximum critical thermal power power in multiple groups of stable boundary powers, and taking the sum of the critical thermal power power and the critical wind power power in the target boundary power as the total control value of the transmission section. In this example, since the system transmission stable section limit value is low when the thermal power output accounts for a high proportion, the total control value of the transmission section is usually taken as the section limit capacity value under the maximum thermal power output mode for conservative consideration, in order to improve the safety of the wind-fire bundled transmission system. In this case, the stability domain of the N-1 stable preventive control of the transmission section obtained in actual operation can be as follows Figure 7 shown.

[0122] The above embodiment proposes a piecewise linear N-1 stable section preventive control scheme for different wind / thermal output states. By analyzing the system stability under different operating modes based on offline simulation calculations of massive operating modes, a piecewise linear section pre-control method is proposed. When the current thermal power power of the wind-fire bundled transmission system is less than or equal to the thermal power critical value, the constraints on wind power are released so that the output of the wind turbine unit is not constrained by the section pre-control requirements. When the current thermal power power is greater than the thermal power critical value, the wind-fire bundled transmission system is pre-controlled to adjust the operating power of each unit in the wind-fire bundled transmission system to ensure the N-1 transient stability of the system output within the safe and stable operation control domain. In this way, the inherent safety of the system grid can be ensured in the context of large-scale new energy production, while avoiding the problem of limited regional transmission capacity caused by overly stringent N-1 section pre-control strategies.

[0123] The following is an explanation of a typical area for wind-thermal bundled transmission. This area is rich in offshore wind resources, which are bundled with regional conventional power sources and transmitted to the main grid through a shared three-circuit line. The regional conventional thermal power source mainly includes G1-G4, 4 units with an installed capacity of 4480MW, and the regional wind turbine units mainly include W1-W8, 8 wind farms with an installed capacity of 2000MW. The typical system structure of regional new energy centralized AC transmission is as follows: Figure 8 shown.

[0124] When a three-phase short circuit single-loop fault occurs on the regional transmission P1-P2 line (hereinafter referred to as P1-P2 line N-1 fault), the regional transmission system has transient power angle stability problems. Based on rapid quantitative analysis and electromechanical transient simulation stability boundary verification, the safe stability domain of the regional transmission system can be obtained, as shown in Table 1 and Figure 9 shown.

[0125] Table 1 Stable calculation

[0126]

[0127] If the traditional section control strategy is used, considering that the system is more susceptible to power angle instability when the thermal power output is at its maximum, a conservative approach is taken, analyzing the stability limits of the transmission section (the P1-P2 line section power) under the maximum thermal power output scenario (corresponding to scenarios 10 and 13). When the thermal power output reaches its maximum of 4500MW and the section power is 5400MW, the power angle of the P1-P2 line N-1 system will be unstable. However, when the section transmission power is 5300MW, the power angle of the P1-P2 line N-1 system will be stable. Therefore, the section control value Pset can be set to 5300MW, meaning that the transmission power must be controlled below 5300MW during regional transmission to ensure system stability.

[0128] In actual system operation, when the proportion of wind power output increases, the system's transient stability improves. For example, in modes 2, 4, 6, 8, 9, 11, and 12, the section output power exceeds 5300MW, and the system power angle stabilizes after the P1-P2 line N-1 event. However, due to stringent section pre-control requirements, the system still needs to reduce the output of regional transmission units, resulting in limited system output capacity.

[0129] If the piecewise linear control method of this application is adopted, when the output of the thermal power unit is 4000MW, the system is stable when the wind turbine unit operates at the maximum operating power of 2000MW. Therefore, when the thermal power unit is less than or equal to 400MW, the output of the wind turbine unit is not limited. Therefore, a piecewise linear section control strategy is proposed:

[0130]

[0131] Among the originally restricted operating modes (modes 2, 4, 6, 8, 9, 11, and 12), in the piecewise linear section control, modes 2, 4, and 9 are not subject to section control constraints, and the unit's delivery capacity is released, as shown in Table 2.

[0132] Table 2 Control strategy comparison table

[0133]

[0134] The following describes the safe and stable section operation control device of the wind and fire baling and delivery system provided in the embodiment of the present application. The safe and stable section operation control device of the wind and fire baling and delivery system described below and the safe and stable section operation control method of the wind and fire baling and delivery system described above can be referenced to each other.

[0135] In some embodiments, as Figure 10 As shown, the present application provides a safe and stable cross-section operation control device 200 for a wind and fire bundle delivery system, comprising:

[0136] An equivalent model building module 202 is used to obtain an equivalent model of the wind and fire bundling delivery system;

[0137] A simulation calculation module 204 is configured to perform transient simulation calculations based on the equivalent model to obtain multiple sets of stable boundary powers; wherein the stable boundary powers are critical thermal power and critical wind power when the wind-thermal bundled delivery system is in a transient power angle stable boundary scenario;

[0138] a thermal power critical value determination module 206, configured to determine a thermal power critical value based on the multiple groups of stable boundary powers; wherein the thermal power critical value is the maximum thermal power when wind power is not limited;

[0139] The control module 208 is used to respond to the current thermal power of the wind-fire bundled delivery system obtained. If the current thermal power is less than or equal to the thermal power critical value, the wind turbine units of the wind-fire bundled delivery system are not pre-controlled; otherwise, the wind-fire bundled delivery system is pre-controlled to adjust the total output power of the wind-fire bundled delivery system to be less than or equal to a predetermined total delivery section control value.

[0140] In some embodiments, the equivalent model is:

[0141]

[0142] Where, is the self-impedance of the thermal power unit in the wind-fire bundled delivery system, is the mutual impedance between the thermal power unit and the receiving system, is the equivalent negative impedance model of the wind turbine generator set; is the equivalent reactance of the first transmission channel, where the first transmission channel is the transmission channel from the thermal power generation unit to the wind turbine generation grid connection point; is the equivalent reactance of the second transmission channel, where the second transmission channel is the transmission channel from the wind turbine grid connection point to the AC power grid; is the imaginary unit, is the current active power of the wind turbine, is the current reactive power of the wind turbine, is the grid connection point voltage of the wind turbine generator system.

[0143] In some embodiments, the simulation calculation module 204 of the present application includes:

[0144] a transient stability margin model construction unit, configured to construct a transient stability margin model according to the equivalent model, the system acceleration model and the system deceleration model of the wind-fire bundling system;

[0145] an initial operating power acquisition unit, configured to analyze and calculate the transient stability margin model according to a preset stability margin value to obtain multiple groups of initial operating powers;

[0146] A power correction unit is used to perform transient simulation calculations on each group of initial operating powers based on the wind power and thermal power in the group of initial operating powers to obtain a system stability result, and to correct the group of initial operating powers based on the system stability result until a preset end condition is met and the stable boundary power is obtained.

[0147] In some embodiments, the power calibration unit of the present application includes:

[0148] a first correction unit configured to, if the system stability result is transient power angle instability, maintain the thermal power in the initial operating power group unchanged, and reduce the wind power in the initial operating power group until the transient power angle is stable, thereby obtaining the stable boundary power; wherein the critical thermal power is the thermal power in the initial operating power group, and the critical wind power is the minimum wind power when the transient power angle is stable;

[0149] The second correction unit is used to maintain the thermal power power in the initial operating power of the group unchanged if the system stability result is transient power angle stability, and to increase the wind power in the initial operating power of the group until the transient power angle becomes unstable, so as to obtain the stable boundary power; wherein the critical thermal power is the thermal power in the initial operating power of the group, and the critical wind power is the maximum wind power under the condition of transient power angle stability.

[0150] In some embodiments, the transient stability margin model is:

[0151]

[0152]

[0153]

[0154]

[0155]

[0156]

[0157] Where, is the transient stability margin model, is the system deceleration model, is the system acceleration model, is the fault removal angle, is the critical power angle of the thermal power unit, is the power angle, is the initial power angle of the thermal power unit; The self-impedance of the thermal power unit in the wind-fire bundled delivery system before the fault is cut off; The mutual impedance between the thermal power unit and the receiving system before the fault is cleared; and Determined based on the equivalent model; is the output voltage of the thermal power unit, is the voltage of the AC grid; is the self-impedance angle of the thermal power unit before the fault is cleared; is the mutual impedance angle of the thermal power unit before the fault is cleared; is the input mechanical power of the thermal power unit, is the rated angular frequency of the wind and fire bundle delivery system, is the synchronous machine inertia time constant, The duration from the time the fault occurs to the time the fault is cleared; is the self-impedance of the thermal power unit after the fault is cleared; The mutual impedance between the thermal power unit and the receiving system after the fault is cleared; is the self-impedance angle of the thermal power unit after the fault is cleared; It is the mutual impedance angle of the thermal power unit after the fault is cleared.

[0158] In some embodiments, the control module 208 of the present application includes:

[0159] The power adjustment unit is used to adjust the actual thermal power and actual wind power of the wind-fire bundled transmission system according to a predetermined transmission section total control value, so that the sum of the adjusted actual thermal power and actual wind power is less than or equal to the transmission section total control value.

[0160] In some embodiments, the safe and stable cross-section operation control device of the air-fire bundle delivery system of the present application further includes:

[0161] The control value determination module is used to determine the target boundary power corresponding to the maximum critical thermal power power in the multiple groups of stable boundary powers, and use the sum of the critical thermal power power and the critical wind power in the target boundary power as the total transmission section control value.

[0162] In one embodiment, the present application also provides a storage medium storing computer-readable instructions. When the computer-readable instructions are executed by one or more processors, the one or more processors execute the steps of the method for controlling the safe and stable section operation of the wind and fire bundling delivery system in any embodiment.

[0163] In one embodiment, the present application also provides a computer device having computer-readable instructions stored therein. When the computer-readable instructions are executed by one or more processors, the one or more processors execute the steps of the method for controlling the safe and stable section operation of the wind and fire bundling delivery system in any embodiment.

[0164] Schematically, Figure 11 This is a schematic diagram of the internal structure of a computer device provided in an embodiment of the present application. In one example, the computer device may be a server. Figure 11 Computer device 900 includes a processing component 902, which further includes one or more processors, and memory resources represented by memory 901 for storing instructions executable by processing component 902, such as application programs. The application programs stored in memory 901 may include one or more modules, each corresponding to a set of instructions. Furthermore, processing component 902 is configured to execute the instructions to perform the steps of the method for controlling the safe and stable cross-section operation of a wind-fire bundle delivery system as described in any of the above-described embodiments.

[0165] The computer device 900 may further include a power supply component 903 configured to perform power management of the computer device 900, a wired or wireless network interface 904 configured to connect the computer device 900 to a network, and an input / output (I / O) interface 905. The computer device 900 may operate based on an operating system stored in the memory 901, such as Windows Server™, Mac OS X™, Unix™, Linux™, Free BSD™, or the like.

[0166] Those skilled in the art will understand that the internal structure of the computer device shown in the present application is merely a block diagram of a partial structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0167] Finally, it should be noted that, in this article, relational terms such as first and second are merely used to distinguish one entity or operation from another, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprise," "include," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. Without further restriction, an element defined by the phrase "comprising a..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element. Herein, "one," "said," "the," and "its" may also include plural forms unless the context clearly indicates otherwise. A plurality refers to at least two, such as 2, 3, 5, or 8. "And / or" includes any and all combinations of the relevant listed items.

[0168] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can be referenced to each other.

[0169] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for controlling the safe and stable cross-section operation of a wind and fire bundle delivery system, characterized in that: The method comprises: Obtain an equivalent model of the air-fire bundle delivery system; A transient simulation calculation is performed based on the equivalent model to obtain multiple sets of stable boundary powers; wherein the stable boundary powers are the critical thermal power and critical wind power when the wind-thermal bundled transmission system is in a transient power angle stable boundary scenario; Determine a thermal power critical value based on the multiple groups of stable boundary powers; wherein the thermal power critical value is the maximum thermal power when the wind power is not limited; In response to the current thermal power of the wind-fire bundle delivery system obtained, if the current thermal power power is less than or equal to the thermal power critical value, the wind turbine units of the wind-fire bundle delivery system are not pre-controlled; otherwise, the wind-fire bundle delivery system is pre-controlled to adjust the total output power of the wind-fire bundle delivery system to be less than or equal to a predetermined total delivery section control value.

2. The method according to claim 1, characterized in that The equivalent model is: Where, is the self-impedance of the thermal power unit in the wind-fire bundled delivery system, is the mutual impedance between the thermal power unit and the receiving system, is the equivalent negative impedance model of the wind turbine generator set; is the equivalent reactance of the first transmission channel, where the first transmission channel is the transmission channel from the thermal power generation unit to the wind turbine generation grid connection point; is the equivalent reactance of the second transmission channel, where the second transmission channel is the transmission channel from the wind turbine grid connection point to the AC power grid; is the imaginary unit, is the current active power of the wind turbine, is the current reactive power of the wind turbine, is the grid connection point voltage of the wind turbine generator system.

3. The method according to claim 1, characterized in that The transient simulation calculation is performed based on the equivalent model to obtain multiple groups of stable boundary powers, including: Constructing a transient stability margin model based on the equivalent model, the system acceleration model and the system deceleration model of the wind-fire bundling system; Analyzing and calculating the transient stability margin model according to a preset stability margin value to obtain multiple groups of initial operating powers; For each group of the initial operating power, a transient simulation calculation is performed based on the wind power and thermal power in the group of initial operating power to obtain a system stability result, and the group of initial operating power is corrected based on the system stability result until the preset end condition is met and the stable boundary power is obtained.

4. The method according to claim 3, characterized in that Correcting the group of initial operating powers according to the system stability result until a preset end condition is met and the stable boundary power is obtained includes: If the system stability result is transient power angle instability, the thermal power in the initial operating power of the group is maintained unchanged, and the wind power in the initial operating power of the group is reduced until the transient power angle is stable, thereby obtaining the stable boundary power; wherein the critical thermal power is the thermal power in the initial operating power of the group, and the critical wind power is the minimum wind power when the transient power angle is stable; If the system stability result is that the transient power angle is stable, the thermal power in the initial operating power of the group is kept unchanged, and the wind power in the initial operating power of the group is increased until the transient power angle becomes unstable, thereby obtaining the stable boundary power; wherein, the critical thermal power is the thermal power in the initial operating power of the group, and the critical wind power is the maximum wind power under the condition of transient power angle stability.

5. The method according to claim 3, characterized in that The transient stability margin model is: Where, is the transient stability margin model, is the system deceleration model, Accelerating the model for the system; is the fault removal angle, is the critical power angle of the thermal power unit, is the power angle, is the initial power angle of the thermal power unit; The self-impedance of the thermal power unit in the wind-fire bundled delivery system before the fault is cut off; The mutual impedance between the thermal power unit and the receiving system before the fault is cleared; and Determined based on the equivalent model; is the output voltage of the thermal power unit, is the voltage of the AC grid; is the self-impedance angle of the thermal power unit before the fault is cleared; is the mutual impedance angle of the thermal power unit before the fault is cleared; is the input mechanical power of the thermal power unit, is the rated angular frequency of the wind and fire bundle delivery system, is the inertia time constant of the synchronous machine, The duration from the time the fault occurs to the time the fault is cleared; is the self-impedance of the thermal power unit after the fault is cleared; The mutual impedance between the thermal power unit and the receiving system after the fault is cleared; is the self-impedance angle of the thermal power unit after the fault is cleared; It is the mutual impedance angle of the thermal power unit after the fault is cleared.

6. The method according to any one of claims 1 to 5, characterized in that The pre-control of the air-fire bundle delivery system includes: According to the predetermined total transmission section control value, the actual thermal power and actual wind power of the wind-fire bundled transmission system are adjusted so that the sum of the adjusted actual thermal power and actual wind power is less than or equal to the total transmission section control value.

7. The method according to claim 6, characterized in that The step of determining the control value of the total amount of the delivery section includes: A target boundary power corresponding to a maximum critical thermal power power is determined in the multiple groups of stable boundary powers, and the sum of the critical thermal power power and the critical wind power in the target boundary power is used as the total transmission section control value.

8. A safe and stable cross-section operation control device for a wind and fire bundle delivery system, characterized in that: The device comprises: Equivalent model building module, used to obtain the equivalent model of the wind and fire bundle delivery system; a simulation calculation module, configured to perform transient simulation calculations based on the equivalent model to obtain multiple sets of stable boundary powers; wherein the stable boundary powers are critical thermal power and critical wind power when the wind-thermal bundled delivery system is in a transient power angle stable boundary scenario; a thermal power critical value determination module, configured to determine a thermal power critical value based on the multiple groups of stable boundary powers; wherein the thermal power critical value is the maximum thermal power when wind power is not limited; a control module, configured to respond to the acquired current thermal power of the wind-fire bundle delivery system, and if the current thermal power is less than or equal to the thermal power critical value, not pre-control the wind turbine units of the wind-fire bundle delivery system; otherwise, pre-control the wind-fire bundle delivery system to adjust the total output power of the wind-fire bundle delivery system to be less than or equal to a predetermined total delivery section control value.

9. A storage medium, characterized in that: The storage medium stores computer-readable instructions. When the computer-readable instructions are executed by one or more processors, the one or more processors execute the steps of the method for controlling the safe and stable section operation of the wind and fire bundling delivery system as described in any one of claims 1 to 7.

10. A computer device, characterized in that: include: one or more processors, and memory; The memory stores computer-readable instructions, which, when executed by the one or more processors, execute the steps of the method for controlling safe and stable cross-section operation of a wind and fire bundling delivery system as described in any one of claims 1 to 7.

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