Emergency machine cutting method of wind-fire bundling delivery system and related device

Abstract

The invention provides an emergency cutting method and related device for a wind-thermal bundled delivery system, and the method comprises the steps: calculating the system acceleration area of the wind-thermal bundled delivery system according to a cutting power angle of the wind-thermal bundled delivery system when a fault generator set is cut off, and a pre-constructed power angle characteristic curve of the wind-thermal bundled delivery system, and calculating the system acceleration area of the wind-thermal bundled delivery system according to the power angle characteristic curve of the wind-thermal bundled delivery system. A system deceleration area calculation expression can be constructed according to the transient stability critical power angle, the cutting power angle and the power angle characteristic curve of the wind-thermal bundled delivery system, and power angle stability constraint conditions are constructed according to the system acceleration area and the system deceleration area calculation expression. The target function with the purpose of minimizing the generator tripping amount of the wind-thermal bundled delivery system is solved by adopting the power angle stability constraint condition, so that a target emergency generator tripping strategy with the minimum generator tripping amount can be obtained. Therefore, the generator tripping combination can be directly determined through analytical equation optimization calculation, and all generator tripping combinations do not need to be traversed through time domain simulation, so that the optimization generation speed of the generator tripping combination can be effectively improved.

Description

Technical Field

[0001] The present application relates to the technical field of power systems, and in particular to an emergency cutting method and related devices for a wind and fire bundling delivery system. Background Art

[0002] With the construction and development of new power systems, the installed capacity of new energy sources is increasing. Due to the different wind conditions in different geographical regions, wind turbines are often concentrated in geographical areas with better wind conditions, such as coastal areas, which leads to the problem of long-distance transmission of wind power generated by wind turbines across regions.

[0003] As the penetration rate of new energy continues to increase, wind power is often bundled with thermal power in geographically adjacent locations, sharing transmission channels to achieve wind and thermal bundled transmission. This can effectively utilize transmission channels, solve the problem of long-distance transmission of wind power, and significantly alleviate the phenomenon of wind abandonment, thus achieving efficient cross-regional allocation of clean energy.

[0004] When a fault occurs in the power system, the power balance in the system is broken and unbalanced power is generated, which causes the generator to accelerate, and then causes transient instability in the system. In this case, some generators can be quickly cut off by cutting the machine to reduce the total mechanical power input in the system, thereby reducing the unbalanced power, slowing down the acceleration trend of the generator, and improving the transient stability of the system. However, under the power transmission mode of wind-fire bundled transmission, there is a complex coupling effect between wind power, thermal power and the power grid, which weakens the transient stability performance of the power system to a certain extent. In addition, the grid connection of wind power changes the power grid's power flow pattern, which in turn constitutes another level of potential impact on the transient stability performance of the power system. Therefore, it is urgent to provide an emergency cutting method for the wind-fire bundled transmission system to improve the transient stability of the wind-fire bundled transmission system.

[0005] In view of the above situation, the prior art proposes a wind-fire coordinated cutting strategy based on the emergency cutting priority coefficient. First, the prior art identifies the thermal power units in the transient stability critical group that are greatly affected by the fault according to the transient stability critical group identification criterion, and takes the thermal power units in the transient stability critical group and the thermal power units in the thermal stability critical group under normal operation as the main cutting objects, and determines the cutting priority coefficient of the thermal power unit according to the speed acceleration of the unit and the load rate of the transmission line. At the same time, the prior art also takes the transient stability critical wind farm that is greatly affected by the fault as the main cutting object, and assigns the cutting priority coefficient of the wind farm on the basis of comprehensively considering the overspeed problem of the wind turbine and the cutting sensitivity. Finally, the prior art solves and calculates according to the cutting priority coefficient of the thermal power unit and the cutting priority coefficient of the wind farm with the goal of minimizing the cutting power, and then determines the emergency cutting strategy.

[0006] However, the existing technology is highly dependent on time-domain simulation calculations when solving the calculations, which has the problem of slow optimization speed, thus affecting the emergency cutting speed. At the same time, the existing technology has insufficient analysis of the impact of wind power grid connection on the transient stability characteristics of the power system, ignoring the factor of the steady-state voltage rise of the system after cutting the machine. Summary of the invention

[0007] The purpose of the present application is to solve at least one of the above-mentioned technical defects, especially the technical defect in the prior art that the optimization speed is slow, thereby affecting the emergency cutting speed.

[0008] In a first aspect, an embodiment of the present application provides an emergency cutting method for a wind and fire bundling delivery system, comprising:

[0009] Obtain a pre-built objective function that aims to minimize the amount of machine cutting for the fire-wind baling delivery system;

[0010] Calculating the cut-off power angle of the wind-fire bundle delivery system when the faulty generator set is cut off, and calculating the system acceleration area according to the cut-off power angle and a pre-constructed power angle characteristic curve of the wind-fire bundle delivery system;

[0011] Calculate the transient stability critical power angle of the wind-fire bundle delivery system, and construct a system deceleration area calculation expression based on the transient stability critical power angle, the cut-off power angle and the power angle characteristic curve;

[0012] According to the calculation expressions of the system acceleration area and the system deceleration area, a power angle stability constraint condition is constructed; the power angle stability constraint condition is used to constrain the wind-fire bundled delivery system to have a system deceleration area greater than or equal to the system acceleration area when the faulty generator set is removed and the emergency generator cutting strategy is adopted for cutting the generator;

[0013] The objective function is solved based on the power angle stability constraint condition, and a target emergency power-off strategy is obtained; the target emergency power-off strategy is used to instruct the wind-fire bundling and delivery system to cut off some non-faulty generator sets.

[0014] In one embodiment, if the non-faulty thermal power unit is cut off, the system deceleration area calculation expression is:

[0015] S d,max =S d +ΔS dt

[0016] If the non-faulty wind turbines are cut off, the system deceleration area calculation expression is:

[0017] S d,max =S d +ΔS dw

[0018] in:

[0019]

[0020] ΔS dt =(P m -P m ′)·(δ2-δ1)

[0021]

[0022] In the formula, S d,max is the system deceleration area of ​​the wind-fire bundled delivery system when the faulty generator set is removed and the emergency generator cutting strategy is adopted; S d is the system deceleration area reference value of the wind and fire bundling delivery system; ΔS dt System deceleration area provided for cutting off non-faulty thermal power units; ΔS dw The system deceleration area provided for cutting off the non-faulty wind turbines; δ1 is the cutting power angle; δ2 is the transient stability critical power angle; Z 11 is the self-impedance of the thermal power unit in the wind-fire bundled transmission system before the faulty generator unit is removed; α is Z 11 The impedance angle of Z 12 The mutual impedance between the thermal power unit and the receiving end system in the wind-fire bundled transmission system before the faulty generator unit is removed; U q is the output voltage of the thermal power unit in the wind-fire bundled delivery system; U s is the voltage of the AC grid; U w is the output voltage of the wind turbine in the wind-fire bundling and delivery system; δ is the power angle of the wind-fire bundling and delivery system; P m The input mechanical power of the thermal power unit in the wind-fire bundle delivery system before cutting off the non-faulty thermal power unit; P m ′ is the input mechanical power of the thermal power unit in the wind-fire bundle delivery system after the non-faulty thermal power unit is cut off; P w is the wind power in the wind-fire bundled transmission system; P w0 The wind power in the wind-fire bundled transmission system before cutting off the non-faulty wind turbines; P w ' v After the non-faulty wind turbines are cut off, the wind power in the wind-fire bundled transmission system; The system deceleration area reference value of the wind-fire bundle delivery system after the non-faulty wind turbines are cut off; R is the system deceleration area reference value of the wind-fire bundle delivery system before cutting off the non-faulty wind turbine set; wis the equivalent negative resistance of the wind turbine generator set; x1 is the equivalent reactance of the first transmission channel before the faulty generator set is cut off, and the first transmission channel is the transmission channel from the thermal power unit to the wind turbine generator grid connection point; x2 is the equivalent reactance of the second transmission channel before the faulty generator set is cut off, and the second transmission channel is the transmission channel from the wind turbine generator grid connection point to the AC power grid; j is an imaginary unit.

[0023] In one embodiment, the system acceleration area is calculated based on the following expression:

[0024]

[0025] In the formula, S a is the acceleration area of ​​the system; ω n is the rated angular frequency of the generator set; T J is the inertia time constant of the synchronous machine; Δt is the interval from the time when the fault occurs to the time when the wind-fire bundling and delivery system cuts off the faulty generator set.

[0026] In one embodiment, the cut-off power angle and the transient stability critical power angle are calculated based on the following expressions:

[0027]

[0028] Wherein, δ0 is the power angle of the wind-fire bundled transmission system in the initial balanced working state; Z1′1 is the self-impedance of the thermal power unit in the wind-fire bundled transmission system after the faulty generator set is removed; α′ is the impedance angle of Z1′1; Z1′2 is the mutual impedance between the thermal power unit and the receiving system in the wind-fire bundled transmission system after the faulty generator set is removed.

[0029] In one embodiment, solving the objective function based on the power angle stability constraint and obtaining a target emergency power-off strategy includes:

[0030] Constructing a voltage over-line constraint condition, wherein the voltage over-line constraint condition is used to constrain the voltage difference between the sending and receiving ends of the wind-fire bundling delivery system to be within a preset voltage range;

[0031] Constructing a wind farm short circuit ratio constraint condition, wherein the wind farm short circuit ratio constraint condition is used to constrain the wind farm short circuit ratio to be greater than or equal to a preset short circuit ratio threshold;

[0032] Based on the power angle stability constraint condition, the voltage crossing constraint condition and the wind farm short circuit ratio constraint condition, the objective function is solved and the target emergency tripping strategy is obtained.

[0033] In one embodiment, the objective function is:

[0034]

[0035] In the formula, G is the set of thermal power generation units; W is the set of wind power generation units; λ t is the preset thermal power cutting weight; u t is the decision variable for the thermal power unit g; ΔP g Active power provided to thermal power unit g; w is the preset wind power curtailment weight, λ w ≤λ t ;u w is the decision variable for the wind turbine w to be switched off; ΔP w The active power provided by the wind turbine w.

[0036] In one embodiment, the voltage crossing constraint condition is:

[0037] -ΔU min ≤ΔU≤ΔU min

[0038]

[0039] Where, ΔU is the pressure difference between the sending and receiving ends of the wind and fire bundling delivery system; ΔU min is the preset voltage threshold; P1 is the active power delivered by the wind-fire bundled transmission system; Q1 is the reactive power delivered by the wind-fire bundled transmission system; x2 is the equivalent reactance of the second transmission channel before the faulty generator set is removed, and the second transmission channel is the transmission channel from the grid connection point of the wind turbine set to the AC power grid; U s is the voltage of the AC grid;

[0040] The wind farm short-circuit ratio constraint corresponding to the i-th wind farm is:

[0041]

[0042] In the formula, S i is the grid-connected short-circuit capacity of the i-th wind farm; S g Short-circuit capacity provided for thermal power unit g; MRSCR i,criticality is the preset critical short circuit ratio; P wi is the operating output of the i-th wind farm; IF ij is the power conversion factor after considering the impact of the j-th wind farm on the ith wind farm; u wj is the decision variable for the wind farm j; P wj is the operating output of the jth wind farm; W is the wind farm set.

[0043] In a second aspect, an embodiment of the present application provides an emergency cutting device for a wind and fire bundling delivery system, comprising:

[0044] An objective function acquisition module is used to acquire a pre-built objective function with the goal of minimizing the amount of machine cutting of the wind and fire bundling delivery system;

[0045] An acceleration area calculation module is used to calculate the cut-off power angle of the wind-fire bundle delivery system when the faulty generator set is cut off, and calculate the system acceleration area according to the cut-off power angle and a pre-constructed power angle characteristic curve of the wind-fire bundle delivery system;

[0046] A deceleration expression building module is used to calculate the transient stability critical power angle of the wind-fire bundle delivery system, and to build a system deceleration area calculation expression according to the transient stability critical power angle, the cut-off power angle and the power angle characteristic curve;

[0047] A power angle stability constraint condition construction module is used to construct a power angle stability constraint condition according to the system acceleration area and the system deceleration area calculation expression; the power angle stability constraint condition is used to constrain the wind-fire bundled transmission system to have a system deceleration area greater than or equal to the system acceleration area when the faulty generator set is removed and the emergency generator cutting strategy is adopted for cutting the generator;

[0048] The target emergency cutting strategy generation module is used to solve the objective function based on the power angle stability constraint condition and obtain the target emergency cutting strategy; the target emergency cutting strategy is used to instruct the wind-fire bundling and delivery system to cut off some non-faulty generator sets.

[0049] 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 emergency cutting method of the wind and fire bundling delivery system described in any of the above embodiments.

[0050] 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;

[0051] The memory stores computer-readable instructions, and when the computer-readable instructions are executed by the one or more processors, the steps of the emergency machine cutting method of the wind and fire bundling delivery system described in any of the above embodiments are performed.

[0052] In the emergency machine cutting method and related device of the wind and fire bundle delivery system provided in some embodiments of the present application, the system acceleration area of ​​the wind and fire bundle delivery system can be calculated according to the power cutting angle of the wind and fire bundle delivery system when the faulty generator set is cut off, and the power angle characteristic curve of the wind and fire bundle delivery system constructed in advance, and the system deceleration area calculation expression can be constructed according to the transient stability critical power angle, the cut-off power angle and the power angle characteristic curve of the wind and fire bundle delivery system, and the power angle stability constraint condition can be constructed according to the system acceleration area and the system deceleration area calculation expression. By using the power angle stability constraint condition to solve the objective function with the goal of minimizing the machine cutting amount of the wind and fire bundle delivery system, the target emergency machine cutting strategy with the minimum machine cutting amount can be obtained under the premise of ensuring the system power angle stability. In this way, the machine cutting combination can be determined directly through analytical equation optimization calculation based on analytical derivation and optimization, without traversing all machine cutting combinations through time domain simulation, thereby effectively improving the optimization generation speed of the machine cutting combination, and further improving the emergency machine cutting speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative labor.

[0054] Figure 1 An equivalent circuit model of a wind and fire bundling and delivery system in one embodiment;

[0055] Figure 2 Schematic diagram of the effect of safety and stability control on transient stability of a generator set in one embodiment;

[0056] Figure 3 A schematic flow chart of an emergency cutting method for a wind and fire bundling delivery system in one embodiment;

[0057] Figure 4 It is a schematic structural diagram of an emergency cutting device of a wind and fire bundling delivery system in one embodiment;

[0058] Figure 5 FIG. 1 is a diagram of the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0059] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0060] In view of the technical problems raised by the background technology, the emergency cutting machine method of the wind and fire bundle delivery system proposed in some embodiments of the present application can build a cutting machine coordination optimization model for the wind and fire bundle delivery system based on the equal area law and the acceleration area and deceleration area of ​​the transient process of the regional delivery system, and realize the optimal configuration of the control cutting amount and control cost through optimization solution. In this way, based on analytical derivation and optimization, the cutting machine combination can be determined directly through analytical equation optimization calculation, without traversing all cutting machine combinations through time domain simulation, thereby effectively improving the optimization generation speed of the cutting machine combination, and then improving the emergency cutting speed.

[0061] Furthermore, in some embodiments, the present application also analyzes the voltage changes after the stable control cutting of the generator, and solves the objective function by means of the voltage crossing constraint condition, thereby avoiding the problem of a sharp drop in the power transmission capacity of the external transmission system caused by insufficient voltage support capacity at the sending and receiving ends after cutting off the non-faulty generator sets, thereby further improving the transient stability of the system.

[0062] The principle of this scheme will be analyzed and described below.

[0063] Specifically, the equivalent circuit model of the wind-fire bundled delivery system can be expressed as Figure 1 As shown, where U q is the output voltage of the thermal power unit in the wind-fire bundled transmission system, U s is the voltage of the AC grid, U w is the output voltage of the wind turbine in the wind-fire bundled transmission system. x1 is the equivalent reactance of the first transmission channel before the faulty generator is removed. The first transmission channel is the transmission channel from the thermal generator to the wind turbine grid connection point. x2 is the equivalent reactance of the second transmission channel before the faulty generator is removed. The second transmission channel is the transmission channel from the wind turbine grid connection point to the AC power grid. I1 is the current of the first transmission channel, and I2 is the current of the second transmission channel.

[0064] Considering that the wind turbine is running in the maximum power tracking control mode and generates active power, the wind turbine can be equivalent to a negative resistance model. If the resistance in the transmission line and transformer is ignored, the equivalent reactance of the first transmission channel is x1, the equivalent reactance of the second transmission channel is x2, and the AC power grid Us is considered as an infinite power source, then the equivalent negative resistance of the wind turbine can be expressed as:

[0065]

[0066] In the formula, R w is the equivalent negative resistance of the wind turbine; U w P is the output voltage of the wind turbine in the wind-fire bundled transmission system; w It is the active power of wind turbines in the wind-fire bundled transmission system.

[0067] For the model of power transmission from a generator to an infinite power grid, the generator operation equation can be expressed as:

[0068]

[0069] In the formula, H is the system synchronous machine inertia; t is time; δ is the system power angle, which can represent the angle difference between the internal potential of the generator and the receiving end system vector; is the second-order derivative of the power angle with respect to time; P m is the input mechanical power of the system; P e is the output electromagnetic power of the system.

[0070] The electromagnetic power P delivered by traditional thermal power units eg It is expressed as:

[0071]

[0072] Where U q is the output voltage of the thermal power unit, U s is the voltage of the AC grid, x1 is the equivalent reactance of the first transmission channel before the faulty generator set is removed, x2 is the equivalent reactance of the second transmission channel before the faulty generator set is removed, and δ is the power angle.

[0073] After considering the wind and fire bundling, write the loop current equation and solve it to get the loop current:

[0074]

[0075] In the formula, is the current vector of the first transmission channel, is the output voltage vector of the thermal power unit, is the voltage vector of the AC grid, R w is the equivalent negative resistance of the wind turbine.

[0076] Consider the electromagnetic power P sent by wind and fire bundling e It is expressed as:

[0077]

[0078] In the formula, is the output voltage vector of the thermal power unit, is the conjugate vector of the current vector of the first transmission channel, Z 11 is the self-impedance of the thermal power unit, Z 12 is the mutual impedance between the thermal power unit and the receiving system, α is Z 11 The impedance angle.

[0079] in:

[0080]

[0081] By comparing formula (3) and formula (5), it can be seen that after the wind turbine is connected, the traditional power angle curve moves downward as the power connected to the wind turbine increases.

[0082] When a failure occurs in the wind and fire bundle delivery system, the equal area method can be used to analyze the system stability. It should be understood that the wind and fire bundle delivery system not only needs to cut off the faulty generator set, but also cut off some non-faulty generator sets to maintain the transient stability of the system. The cutting of generators described in this article can be understood as a cutting strategy for non-faulty generator sets.

[0083] Please combine Figure 2 , assuming P e is the output electromagnetic power of the wind and fire bundling and delivery system. δ0 is the power angle of the wind and fire bundling and delivery system in the initial balanced working state, which can be the system power angle before the wind and fire bundling and delivery system fails. This application can be combined with the electromagnetic power curve before the failure and the input mechanical power P of the system. m Solution:

[0084]

[0085] Where δ0 is the power angle of the wind-fire bundled delivery system in the initial balanced working state; Z 11 is the self-impedance of the thermal power unit before the fault; Z 12 is the mutual impedance between the thermal power unit and the receiving system before the fault; U q The output voltage of the thermal power unit in the wind-fire bundled transmission system; U s is the voltage of the AC grid; α is Z 11 The impedance angle.

[0086] Consider a three-phase grounding fault at the grid connection point of the thermal power unit. The impact of this fault is the most serious. During the fault, the output electromagnetic power of the thermal power unit is 0, and the output electromagnetic power of the wind-fire bundled transmission system changes from the initial P before the fault to I The curve becomes P after the fault II Curve. Assuming the input mechanical power P mThe generator rotor begins to accelerate, and the system cuts off the faulty generator and takes cutting measures Δt seconds after the fault occurs. At the moment of cutting off the faulty generator, the rotor angle of the generator is δ1. The cutting power angle δ1 can be calculated according to the generator rotor motion equation:

[0087]

[0088] Where, δ0 is the power angle of the wind-fire bundled delivery system in the initial balanced working state; ω n is the rated angular frequency of the generator set; T J is the inertia time constant of the synchronous machine; Δt is the interval from the time the fault occurs to the time when the wind-fire bundling and delivery system cuts off the faulty generator set.

[0089] In this case, the acceleration area S of the wind-fire bundled delivery system at the moment of removal of the faulty generator set can be calculated: a :

[0090]

[0091] If only the faulty generator set is removed, the reactance of the first transmission channel and the reactance of the second transmission channel will change, causing the self-impedance and mutual impedance of the thermal power unit to change accordingly. The changed self-impedance Z1′1 and mutual impedance Z1′2 can be calculated based on the reactance of the first transmission channel, the reactance of the second transmission channel and formula (6) after the faulty generator set is removed. On this basis, the present application calculates the transient stability critical power angle δ2 based on formula (10):

[0092]

[0093] Wherein, Z1′1 is the self-impedance of the thermal power unit in the wind-fire bundled transmission system after the faulty generator unit is removed; Z1′2 is the mutual impedance between the thermal power unit and the receiving system in the wind-fire bundled transmission system after the faulty generator unit is removed; α′ is the impedance angle of Z1′1. Since a certain fault is considered (for example, a three-phase grounding fault occurs at the grid connection point of the thermal power unit), α′ is also determined.

[0094] Based on the transient stability critical power angle δ2, the system deceleration area reference value S of the wind-fire bundle delivery system can be calculated. d :

[0095]

[0096] Furthermore, please combine Figure 2 In the decision of cutting off the thermal power unit and / or the wind power unit, before cutting off the thermal power unit, the input mechanical power of the system is P m After the thermal power unit is removed, the input mechanical power of the system drops to Pm ′, so the system deceleration area ΔS provided by the non-faulty thermal power unit is cut off dt It can be approximately calculated using the following formula:

[0097] ΔS dt =(P m -P m ′)·(δ2-δ1) (12)

[0098] If the wind turbine is removed, the power angle curve moves upward, increasing the deceleration area ΔS of the transmission system. dw , ΔS dw It can be expressed as:

[0099]

[0100] Where P w P is the wind power in the wind-thermal bundled transmission system; w0 Before cutting off the non-faulty wind turbines, the wind power in the wind-fire bundled transmission system; P w 'After cutting off the non-faulty wind turbines, the wind power in the wind-fire bundled transmission system; It is the system deceleration area reference value of the wind-fire bundled transmission system after the non-faulty wind turbines are cut off; It is the system deceleration area reference value of the wind-fire bundled transmission system before cutting off the non-faulty wind turbines; R w is the equivalent negative resistance of the wind turbine;

[0101] During the emergency cutting process of wind and fire bundling, it is also necessary to consider the problem that after the generator set is cut off, the voltage support capacity of the sending and receiving ends is reduced, causing the transmission capacity of the external transmission system to drop sharply. Assuming that the active power sent by the wind and fire bundling is P1 and the reactive power is Q1, the voltage drop can be calculated by the following formula:

[0102]

[0103] Wherein, ΔU is the pressure difference between the sending and receiving ends of the wind-fire bundled transmission system; P1 is the active power delivered by the wind-fire bundled transmission system; Q1 is the reactive power delivered by the wind-fire bundled transmission system; x2 is the equivalent reactance of the second transmission channel before the faulty generator set is removed. The second transmission channel is the transmission channel from the wind turbine grid connection point to the AC power grid; U s is the voltage of the AC grid.

[0104] The solution of the present application will be described below in combination with the above principles.

[0105] In one embodiment, Figure 3 As shown, the present application provides an emergency cutting method for a wind and fire bundling delivery system, comprising the following steps:

[0106] S302: Obtain a pre-built objective function that aims to minimize the amount of machine cutting in the wind and fire baling delivery system.

[0107] In this step, according to the above principle analysis, it can be concluded that in the case of transient instability of the system after a fault, the wind-fire bundled delivery system needs to adopt an emergency machine cutting strategy to cut off non-faulty thermal power units and / or non-faulty wind power units. Since there are multiple machine cutting combinations, in order to ensure the economy of the machine cutting strategy, the objective function can be constructed by minimizing the machine cutting amount as the goal.

[0108] Furthermore, in one example, considering that the control cost of a thermal power unit is higher than that of a wind power unit, different tripping weights can be set for the thermal power unit and the wind power unit in advance, and the tripping weight of the thermal power unit is set to be greater than that of the wind power unit, so as to further reduce the tripping cost. In this example, the objective function can be:

[0109]

[0110] In the formula, G is the set of thermal power generation units; W is the set of wind power generation units; λ t is the preset thermal power cutting weight; u t is the decision variable for the thermal power unit g; ΔP g Active power provided to thermal power unit g; w is the preset wind power curtailment weight, λ w ≤λ t ;u w is the decision variable for the wind turbine w to be switched off; ΔP w The active power provided by the wind turbine w.

[0111] Among them, u t and u w Both can be 0-1 variables, 0 means no machine cut, 1 means machine cut.

[0112] S304: Calculate the cut-off power angle of the wind-fire bundled transmission system when the faulty generator set is cut off, and calculate the system acceleration area according to the cut-off power angle and a pre-built power angle characteristic curve of the wind-fire bundled transmission system.

[0113] The cut-off power angle refers to the system power angle of the wind-fire bundled delivery system when the faulty generator set is cut off. For example, if the system fails at time T0 and the faulty generator set is cut off after Δt, the cut-off power angle can be the power angle of the wind-fire bundled delivery system at time (T0+Δt). The system acceleration area can be used to reflect the acceleration of the non-faulty generator set in the wind-fire bundled delivery system. The power angle characteristic curve can be expressed as formula (3), formula (5) and Figure 2 shown.

[0114] In one example, the cut-off angle can be calculated based on the following expression:

[0115]

[0116] Where, δ0 is the power angle of the wind-fire bundled delivery system in the initial balanced working state; δ1 is the cut-off power angle; Z 11 is the self-impedance of the thermal power unit in the wind-fire bundled transmission system before the faulty generator unit is removed; α is Z 11 The impedance angle of Z 12 The mutual impedance between the thermal power unit and the receiving system in the wind-fire bundled transmission system before the faulty generator unit is removed; U q The output voltage of the thermal power unit in the wind-fire bundled transmission system; U s is the voltage of the AC grid; P m The input mechanical power of the thermal power unit in the wind-fire bundled transmission system before cutting off the non-faulty thermal power unit; ω n is the rated angular frequency of the generator set; T J is the inertia time constant of the synchronous machine; Δt is the interval from the time the fault occurs to the time when the wind-fire bundling and delivery system cuts off the faulty generator set.

[0117] In another example, the system acceleration area S a It can be calculated based on the following expression:

[0118]

[0119] In the formula, ω n is the rated angular frequency of the generator set; T J is the inertia time constant of the synchronous machine; Δt is the interval from the time the fault occurs to the time when the wind-fire bundling and delivery system cuts off the faulty generator set.

[0120] S306: Calculate the transient stability critical power angle of the wind-fire bundled delivery system, and construct a system deceleration area calculation expression based on the transient stability critical power angle, the cut-off power angle and the power angle characteristic curve.

[0121] Among them, the transient stability critical power angle refers to the power angle when the wind-fire bundled transmission system is in a critical state of transient stability and transient instability. The system deceleration area calculation expression can be used to measure the deceleration that can be brought about by removing some non-faulty generator sets.

[0122] In an example, the transient stability critical power angle can be calculated based on the following expression:

[0123]

[0124] Where δ2 is the critical power angle of transient stability; Z1′1 is the self-impedance of the thermal power unit in the wind-fire bundled transmission system after the faulty generator unit is removed; α′ is the impedance angle of Z1′1; Z1′2 is the mutual impedance between the thermal power unit and the receiving system in the wind-fire bundled transmission system after the faulty generator unit is removed; U q The output voltage of the thermal power unit in the wind-fire bundled transmission system; U s is the voltage of the AC grid; P m To input mechanical power to the thermal power units in the wind-fire bundled transmission system before cutting off the non-faulty thermal power units.

[0125] In another example, combined with the above analysis and description, if the non-faulty thermal power units are cut off, the system deceleration area calculation expression can be:

[0126] S d,max =S d +ΔS dt

[0127] If the non-faulty wind turbines are cut off, the system deceleration area calculation expression can be:

[0128] S d,max =S d +ΔS dw

[0129] In the formula, S d,max S is the system deceleration area of ​​the wind-fire bundled transmission system when the faulty generator set is removed and the emergency generator cutting strategy is adopted; d ΔS is the system deceleration area reference value of the wind and fire bundle delivery system; dt System deceleration area provided for cutting off non-faulty thermal power units; ΔS dw System deceleration area provided for cutting off non-faulty wind turbines.

[0130] in:

[0131]

[0132] ΔS dt =(P m -P m ′)·(δ2-δ1)

[0133]

[0134]

[0135] Where, δ1 is the cut-off power angle; δ2 is the transient stability critical power angle; Z 11 is the self-impedance of the thermal power unit in the wind-fire bundled transmission system before the faulty generator unit is removed; α is Z 11 The impedance angle of Z12 The mutual impedance between the thermal power unit and the receiving system in the wind-fire bundled transmission system before the faulty generator unit is removed; U q The output voltage of the thermal power unit in the wind-fire bundled transmission system; U s is the voltage of the AC grid; U w is the output voltage of the wind turbine in the wind-fire bundled transmission system; δ is the power angle of the wind-fire bundled transmission system; P m The input mechanical power of the thermal power unit in the wind-fire bundled transmission system before cutting off the non-faulty thermal power unit; P m ′ is the input mechanical power of the thermal power unit in the wind-fire bundled transmission system after the non-fault thermal power unit is cut off; P w P is the wind power in the wind-thermal bundled transmission system; w0 Before cutting off the non-faulty wind turbines, the wind power in the wind-fire bundled transmission system; P w 'After cutting off the non-faulty wind turbines, the wind power in the wind-fire bundled transmission system; It is the system deceleration area reference value of the wind-fire bundled transmission system after the non-faulty wind turbines are cut off; It is the system deceleration area reference value of the wind-fire bundled transmission system before cutting off the non-faulty wind turbines; R w is the equivalent negative resistance of the wind turbine; x1 is the equivalent reactance of the first transmission channel before the faulty generator set is removed, and the first transmission channel is the transmission channel from the thermal power unit to the wind turbine grid connection point; x2 is the equivalent reactance of the second transmission channel before the faulty generator set is removed, and the second transmission channel is the transmission channel from the wind turbine grid connection point to the AC power grid; j is an imaginary unit.

[0136] S308: Constructing a power angle stability constraint condition according to the calculation expressions of the system acceleration area and the system deceleration area.

[0137] Among them, the power angle stability constraint condition is used to constrain the wind-fire bundled transmission system to cut off the faulty generator set and adopt the emergency cutting strategy to cut the generator. The system deceleration area must be greater than or equal to the system acceleration area to ensure the transient stability of the system. That is, the power angle stability constraint condition can be: S d,max ≥S a .

[0138] S310: Solving the objective function based on the power angle stability constraint condition and obtaining the target emergency machine cutting strategy; the target emergency machine cutting strategy is used to instruct the wind-fire bundled transmission system to cut off some non-faulty generator sets.

[0139] In this step, the objective function can be solved according to the power angle stability constraint, and the problem of the emergency cutting strategy can be transformed into a 0-1 planning problem, and the optimal cutting strategy that satisfies the objective function and the power angle stability constraint is obtained, that is, the target emergency cutting strategy. The wind-fire bundled delivery system cuts off the non-faulty generator set according to the target emergency cutting strategy to maintain the transient stability of the system.

[0140] In one example, the present application may adopt the branch and bound method for solving.

[0141] This embodiment can determine the machine cutting combination directly through analytical equation optimization calculation based on analytical derivation and optimization, without traversing all machine cutting combinations through time domain simulation, thereby effectively improving the optimization generation speed of the machine cutting combination and further improving the emergency machine cutting speed.

[0142] In one embodiment, solving the objective function based on the power angle stability constraint condition and obtaining the target emergency generator trip strategy includes:

[0143] Step A1: Construct voltage crossing constraint conditions.

[0144] Among them, the voltage over-line constraint condition is used to constrain the voltage difference between the sending and receiving ends of the wind-fire bundled transmission system to be within the preset voltage range. During the emergency cutting of the wind-fire bundled generator, it is also necessary to consider the problem that after the non-faulty generator set is cut off, the voltage support capacity of the sending and receiving ends is reduced, causing the transmission capacity of the transmission system to drop sharply. Therefore, the voltage over-line constraint condition can be used to limit the degree of decline in the transmission capacity of the transmission system.

[0145] In one example, the voltage crossing constraint condition may be:

[0146] -ΔU min ≤ΔU≤ΔU min

[0147]

[0148] Where, ΔU is the pressure difference between the sending and receiving ends of the wind and fire bundle delivery system; ΔU min is the preset voltage threshold; P1 is the active power delivered by the wind-fire bundled transmission system; Q1 is the reactive power delivered by the wind-fire bundled transmission system; x2 is the equivalent reactance of the second transmission channel before the faulty generator set is removed. The second transmission channel is the transmission channel from the wind turbine grid connection point to the AC grid; U s is the voltage of the AC grid.

[0149] Step A3: Construct wind farm short circuit ratio constraint conditions.

[0150] The wind farm short circuit ratio constraint condition is used to constrain the short circuit ratio of the wind farm to be greater than or equal to a preset short circuit ratio threshold.

[0151] Specifically, the short-circuit ratio of multiple renewable energy stations is an important indicator for measuring the strength of regional voltage support in the system. In the regional transmission system, if a fault occurs, the short-circuit ratio of multiple renewable energy stations will decrease after the thermal power units are removed. In order to ensure system stability and minimize oscillation and voltage stability problems at renewable energy stations (such as wind farms), the short-circuit ratio constraints of multiple renewable energy stations need to be considered:

[0152]

[0153] Where, MRSCR i is the short-circuit ratio of multiple renewable energy stations at the grid-connected busbar of the i-th renewable energy station; S si is the grid-connected short-circuit capacity of the i-th new energy station; P wi Provide power for the operation of the i-th new energy station; IF ij is the power conversion factor after considering the impact of the j-th renewable energy station on the i-th renewable energy station, which is related to the mutual impedance between the stations. ij Can be |Z ij / Z ii |, Z ij is the mutual impedance between the jth new energy station and the ith new energy station, Z ii is the self-impedance of the i-th new energy station; P wj Contribute to the operation of the jth new energy station.

[0154] In one example, considering that the short-circuit ratio of multiple stations on the low-voltage side of the new energy power generation unit should not be less than 1.5, and the short-circuit ratio of multiple stations at the new energy grid connection point should not be less than 2.0, the critical short-circuit ratio MRSCR is set comprehensively. i,criticality is 2.0, and the wind farm short-circuit ratio constraint corresponding to the i-th wind farm is:

[0155]

[0156] In the formula, S i is the grid-connected short-circuit capacity of the i-th wind farm; S g The short-circuit capacity provided for thermal power unit g; u t is the decision variable for the shutdown of thermal power unit g; MRSCR i,criticality is the preset critical short circuit ratio; P wi is the operating output of the i-th wind farm; IF ij is the power conversion factor after considering the impact of the j-th wind farm on the ith wind farm; u wj is the decision variable for the wind farm j; P wj is the operating output of the jth wind farm; W is the wind farm set.

[0157] Step A5: Based on the power angle stability constraint, the voltage crossing constraint and the wind farm short circuit ratio constraint, solve the objective function and obtain the target emergency tripping strategy.

[0158] For example, the branch and bound method can be used to solve the objective function to obtain the target emergency machine switching strategy.

[0159] In this way, the power angle stability of the system after the generator is cut, the problem of reduced power transmission capacity and the short-circuit ratio of the wind farm can be comprehensively considered, thereby further improving the transient stability of the system.

[0160] The emergency cutting device of the wind and fire baling and delivery system provided in the embodiment of the present application is described below. The emergency cutting device of the wind and fire baling and delivery system described below and the emergency cutting method of the wind and fire baling and delivery system described above can be referenced to each other.

[0161] In one embodiment, Figure 4 As shown, the present application provides an emergency cutting device 400 of a wind and fire bundling delivery system, comprising:

[0162] An objective function acquisition module 402 is used to acquire a pre-built objective function with the goal of minimizing the amount of machine cutting in the wind and fire bundling delivery system;

[0163] The acceleration area calculation module 404 is used to calculate the cut-off power angle of the wind-fire bundle delivery system when the faulty generator set is cut off, and calculate the system acceleration area according to the cut-off power angle and the pre-constructed power angle characteristic curve of the wind-fire bundle delivery system;

[0164] A deceleration expression building module 406 is used to calculate the transient stability critical power angle of the wind-fire bundle delivery system, and to build a system deceleration area calculation expression according to the transient stability critical power angle, the cut-off power angle and the power angle characteristic curve;

[0165] The power angle stability constraint condition building module 408 is used to build a power angle stability constraint condition according to the system acceleration area and the system deceleration area calculation expression; the power angle stability constraint condition is used to constrain the wind-fire bundled delivery system to have a system deceleration area greater than or equal to the system acceleration area when the faulty generator set is removed and the emergency generator cutting strategy is adopted for cutting the generator;

[0166] The target emergency machine-cutting strategy generation module 410 is used to solve the target function based on the power angle stability constraint condition and obtain the target emergency machine-cutting strategy; the target emergency machine-cutting strategy is used to instruct the wind-fire bundling and delivery system to cut off some non-faulty generator sets.

[0167] In one embodiment, the deceleration expression building module is used for cutting off the non-faulty thermal power unit, and the system deceleration area calculation expression is:

[0168] S d,max =S d +ΔS dt

[0169] The deceleration expression building module is used for cutting off the non-faulty wind turbines, and the system deceleration area calculation expression is:

[0170] S d,max =S d +ΔS dw

[0171] in:

[0172]

[0173] ΔS dt =(P m -P m ′)·(δ2-δ1)

[0174]

[0175]

[0176] In the formula, S d,max is the system deceleration area of ​​the wind-fire bundled delivery system when the faulty generator set is removed and the emergency generator cutting strategy is adopted; S d is the system deceleration area reference value of the wind and fire bundling delivery system; ΔS dt System deceleration area provided for cutting off non-faulty thermal power units; ΔS dw The system deceleration area provided for cutting off the non-faulty wind turbines; δ1 is the cutting power angle; δ2 is the transient stability critical power angle; Z 11 is the self-impedance of the thermal power unit in the wind-fire bundled transmission system before the faulty generator unit is removed; α is Z 11 The impedance angle of Z 12 The mutual impedance between the thermal power unit and the receiving end system in the wind-fire bundled transmission system before the faulty generator unit is removed; U q is the output voltage of the thermal power unit in the wind-fire bundled delivery system; U s is the voltage of the AC grid; U w is the output voltage of the wind turbine in the wind-fire bundling and delivery system; δ is the power angle of the wind-fire bundling and delivery system; P m The input mechanical power of the thermal power unit in the wind-fire bundle delivery system before cutting off the non-faulty thermal power unit; P m′ is the input mechanical power of the thermal power unit in the wind-fire bundle delivery system after the non-faulty thermal power unit is cut off; P w is the wind power in the wind-fire bundled transmission system; P w0 The wind power in the wind-fire bundled transmission system before cutting off the non-faulty wind turbines; P w 'After the non-faulty wind turbines are cut off, the wind power in the wind-fire bundled transmission system; The system deceleration area reference value of the wind-fire bundle delivery system after the non-faulty wind turbines are cut off; R is the system deceleration area reference value of the wind-fire bundle delivery system before cutting off the non-faulty wind turbine set; w is the equivalent negative resistance of the wind turbine generator set; x1 is the equivalent reactance of the first transmission channel before the faulty generator set is cut off, and the first transmission channel is the transmission channel from the thermal power unit to the wind turbine generator grid connection point; x2 is the equivalent reactance of the second transmission channel before the faulty generator set is cut off, and the second transmission channel is the transmission channel from the wind turbine generator grid connection point to the AC power grid; j is an imaginary unit.

[0177] In one embodiment, the acceleration area calculation module is used to calculate the system acceleration area based on the following expression:

[0178]

[0179] In the formula, S a is the acceleration area of ​​the system; ω n is the rated angular frequency of the generator set; T J is the inertia time constant of the synchronous machine; Δt is the interval from the time when the fault occurs to the time when the wind-fire bundling and delivery system cuts off the faulty generator set.

[0180] In one embodiment, the acceleration area calculation module is used to calculate the resection angle based on the following expression:

[0181]

[0182] The deceleration expression building module is used to calculate the transient stability critical power angle based on the following expression:

[0183]

[0184] Wherein, δ0 is the power angle of the wind-fire bundled transmission system in the initial balanced working state; Z1′1 is the self-impedance of the thermal power unit in the wind-fire bundled transmission system after the faulty generator set is removed; α′ is the impedance angle of Z1′1; Z1′2 is the mutual impedance between the thermal power unit and the receiving system in the wind-fire bundled transmission system after the faulty generator set is removed.

[0185] In one embodiment, the target emergency switching strategy generation module includes:

[0186] A voltage over-line constraint condition construction unit, used to construct a voltage over-line constraint condition, wherein the voltage over-line constraint condition is used to constrain the voltage difference between the sending and receiving ends of the wind-fire bundling delivery system to be within a preset voltage range;

[0187] A wind farm short circuit ratio constraint condition construction unit, used to construct a wind farm short circuit ratio constraint condition, wherein the wind farm short circuit ratio constraint condition is used to constrain the short circuit ratio of the wind farm to be greater than or equal to a preset short circuit ratio threshold;

[0188] A solving unit is used to solve the objective function based on the power angle stability constraint condition, the voltage crossing constraint condition and the wind farm short circuit ratio constraint condition, and obtain the target emergency tripping strategy.

[0189] In one embodiment, the objective function is:

[0190]

[0191] In the formula, G is the set of thermal power generation units; W is the set of wind power generation units; λ t is the preset thermal power cutting weight; u t is the decision variable for the thermal power unit g; ΔP g Active power provided to thermal power unit g; w is the preset wind power curtailment weight, λ w ≤λ t ;u w is the decision variable for the wind turbine w to be switched off; ΔP w The active power provided by the wind turbine w.

[0192] In one embodiment, the voltage crossing constraint condition is:

[0193] -ΔU min ≤ΔU≤ΔU min

[0194]

[0195] Where, ΔU is the pressure difference between the sending and receiving ends of the wind and fire bundling delivery system; ΔU min is the preset voltage threshold; P1 is the active power delivered by the wind-fire bundled transmission system; Q1 is the reactive power delivered by the wind-fire bundled transmission system; x2 is the equivalent reactance of the second transmission channel before the faulty generator set is removed, and the second transmission channel is the transmission channel from the grid connection point of the wind turbine set to the AC power grid; U s is the voltage of the AC grid;

[0196] The wind farm short-circuit ratio constraint corresponding to the i-th wind farm is:

[0197]

[0198] In the formula, S i is the grid-connected short-circuit capacity of the i-th wind farm; S g Short-circuit capacity provided for thermal power unit g; MRSCR i,criticality is the preset critical short circuit ratio; P wi is the operating output of the i-th wind farm; IF ij is the power conversion factor after considering the impact of the j-th wind farm on the ith wind farm; u wj is the decision variable for the wind farm j; P wj is the operating output of the jth wind farm; W is the wind farm set.

[0199] 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 emergency cutting method of the fire and wind bundling delivery system in any embodiment.

[0200] 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 emergency cutting method of the fire and wind baling delivery system in any embodiment.

[0201] Indicatively, Figure 5 The internal structure diagram of a computer device provided in an embodiment of the present application is shown in FIG. 1 . In one example, the computer device may be a server. Figure 5 The computer device 900 includes a processing component 902, which further includes one or more processors, and a memory resource represented by a memory 901, for storing instructions executable by the processing component 902, such as an application. The application stored in the memory 901 may include one or more modules, each corresponding to a set of instructions. In addition, the processing component 902 is configured to execute instructions to perform the steps of the emergency cutting method of the wind and fire baling delivery system described in any of the above embodiments.

[0202] 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 TM, Mac OS X TM, Unix TM, Linux TM, Free BSD TM or the like.

[0203] 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 scheme of the present application, and does not constitute a limitation on the computer device to which the scheme of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0204] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the term "include", "comprise" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not clearly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements. Herein, "one", "one", "said", "the" and "it" may also include plural forms, unless the context clearly indicates another way. A plurality refers to at least two cases, such as 2, 3, 5 or 8, etc. "And / or" includes any and all combinations of the relevant listed items.

[0205] 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 refer to each other.

[0206] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those 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 will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An emergency cutting method for a wind and fire bundling delivery system, characterized in that: include: Obtain a pre-built objective function that aims to minimize the amount of machine cutting for the fire-wind baling delivery system; Calculating the cut-off power angle of the wind-fire bundle delivery system when the faulty generator set is cut off, and calculating the system acceleration area according to the cut-off power angle and a pre-constructed power angle characteristic curve of the wind-fire bundle delivery system; Calculate the transient stability critical power angle of the wind-fire bundle delivery system, and construct a system deceleration area calculation expression based on the transient stability critical power angle, the cut-off power angle and the power angle characteristic curve; According to the calculation expressions of the system acceleration area and the system deceleration area, a power angle stability constraint condition is constructed; The power angle stability constraint condition is used to constrain the wind-fire bundled delivery system to have a system deceleration area greater than or equal to the system acceleration area when the faulty generator set is removed and the emergency generator cutting strategy is adopted; Solving the objective function based on the power angle stability constraint condition and obtaining a target emergency generator trip strategy; The target emergency power-off strategy is used to instruct the wind-fire bundling and delivery system to cut off some non-faulty power generating sets.

2. The method according to claim 1, characterized in that If the non-faulty thermal power units are cut off, the calculation expression of the system deceleration area is: S d,max =S d +ΔS dt If the non-faulty wind turbines are cut off, the system deceleration area calculation expression is: S d,max =S d +ΔS dw in: ΔS dt =(P m -P′ m )·(δ2-δ1) In the formula, S d,max is the system deceleration area of ​​the wind-fire bundled delivery system when the faulty generator set is removed and the emergency generator cutting strategy is adopted; S d is the system deceleration area reference value of the wind and fire bundling delivery system; ΔS dt System deceleration area provided for cutting off non-faulty thermal power units; ΔS dw The system deceleration area provided for cutting off the non-faulty wind turbines; δ1 is the cutting power angle; δ2 is the transient stability critical power angle; Z 11 is the self-impedance of the thermal power unit in the wind-fire bundled transmission system before the faulty generator unit is removed; α is Z 11 The impedance angle of Z 12 The mutual impedance between the thermal power unit and the receiving end system in the wind-fire bundled transmission system before the faulty generator unit is removed; U q is the output voltage of the thermal power unit in the wind-fire bundled delivery system; U s is the voltage of the AC grid; U w is the output voltage of the wind turbine in the wind-fire bundling and delivery system; δ is the power angle of the wind-fire bundling and delivery system; P m The input mechanical power of the thermal power unit in the wind-fire bundle delivery system before cutting off the non-faulty thermal power unit; P′ m The input mechanical power of the thermal power unit in the wind-fire bundle delivery system after the non-fault thermal power unit is cut off; P w is the wind power in the wind-fire bundled transmission system; P w0 The wind power in the wind-fire bundled transmission system before the non-faulty wind turbines are cut off; P′ w After the non-faulty wind turbines are cut off, the wind power in the wind-fire bundled transmission system; The system deceleration area reference value of the wind-fire bundle delivery system after the non-faulty wind turbines are cut off; R is the system deceleration area reference value of the wind-fire bundle delivery system before cutting off the non-faulty wind turbine set; w is the equivalent negative resistance of the wind turbine generator set; x1 is the equivalent reactance of the first transmission channel before the faulty generator set is cut off, and the first transmission channel is the transmission channel from the thermal power unit to the wind turbine generator grid connection point; x2 is the equivalent reactance of the second transmission channel before the faulty generator set is cut off, and the second transmission channel is the transmission channel from the wind turbine generator grid connection point to the AC power grid; j is an imaginary unit.

3. The method according to claim 2, characterized in that The system acceleration area is calculated based on the following expression: In the formula, S a is the acceleration area of ​​the system; ω n is the rated angular frequency of the generator set; T J is the inertia time constant of the synchronous machine; Δt is the interval from the time when the fault occurs to the time when the wind-fire bundling and delivery system cuts off the faulty generator set.

4. The method according to claim 3, characterized in that The cut-off power angle and the transient stability critical power angle are calculated based on the following expressions: Where, δ0 is the power angle of the wind-fire bundled transmission system in the initial balanced working state; Z1′1 is the self-impedance of the thermal power unit in the wind-fire bundled transmission system after the faulty generator set is removed; α′ is Z′ 11 The impedance angle; Z′ 12 The mutual impedance between the thermal power generating set and the receiving end system in the wind-fire bundled transmission system after the faulty generating set is removed.

5. The method according to any one of claims 1 to 4, characterized in that: The solving the objective function based on the power angle stability constraint condition and obtaining a target emergency generator switching strategy includes: Constructing a voltage over-line constraint condition, wherein the voltage over-line constraint condition is used to constrain the voltage difference between the sending and receiving ends of the wind-fire bundling delivery system to be within a preset voltage range; Constructing a wind farm short circuit ratio constraint condition, wherein the wind farm short circuit ratio constraint condition is used to constrain the wind farm short circuit ratio to be greater than or equal to a preset short circuit ratio threshold; Based on the power angle stability constraint condition, the voltage crossing constraint condition and the wind farm short circuit ratio constraint condition, the objective function is solved and the target emergency tripping strategy is obtained.

6. The method according to claim 5, characterized in that The objective function is: In the formula, G is the set of thermal power generation units; W is the set of wind power generation units; λ t is the preset thermal power cutting weight; u t is the decision variable for the thermal power unit g; ΔP g Active power provided to thermal power unit g; w is the preset wind power curtailment weight, λ w ≤λ t ;u w is the decision variable for the wind turbine w to be switched off; ΔP w The active power provided by the wind turbine w.

7. The method according to claim 6, characterized in that The voltage crossing constraint condition is: -ΔU min ≤ΔU≤ΔU min Where, ΔU is the pressure difference between the sending and receiving ends of the wind and fire bundling delivery system; ΔU min is the preset voltage threshold; P1 is the active power delivered by the wind-fire bundled transmission system; Q1 is the reactive power delivered by the wind-fire bundled transmission system; x2 is the equivalent reactance of the second transmission channel before the faulty generator set is removed, and the second transmission channel is the transmission channel from the grid connection point of the wind turbine set to the AC power grid; U s is the voltage of the AC grid; The wind farm short-circuit ratio constraint corresponding to the i-th wind farm is: In the formula, S i is the grid-connected short-circuit capacity of the i-th wind farm; S g Short-circuit capacity provided for thermal power unit g; MRSCR i,criticality is the preset critical short circuit ratio; P wi is the operating output of the i-th wind farm; IF ij is the power conversion factor after considering the impact of the j-th wind farm on the ith wind farm; u wj is the decision variable for the wind farm j; wj is the operating output of the jth wind farm; W is the wind farm set.

8. An emergency cutting device for a wind and fire bundling delivery system, characterized in that: include: An objective function acquisition module is used to acquire a pre-built objective function with the goal of minimizing the amount of machine cutting of the wind and fire bundling delivery system; An acceleration area calculation module is used to calculate the cut-off power angle of the wind-fire bundle delivery system when the faulty generator set is cut off, and calculate the system acceleration area according to the cut-off power angle and a pre-constructed power angle characteristic curve of the wind-fire bundle delivery system; A deceleration expression building module is used to calculate the transient stability critical power angle of the wind-fire bundle delivery system, and to build a system deceleration area calculation expression according to the transient stability critical power angle, the cut-off power angle and the power angle characteristic curve; A power angle stability constraint condition construction module is used to construct a power angle stability constraint condition according to the system acceleration area and the system deceleration area calculation expression; the power angle stability constraint condition is used to constrain the wind-fire bundled transmission system to have a system deceleration area greater than or equal to the system acceleration area when the faulty generator set is removed and the emergency generator cutting strategy is adopted for cutting the generator; A target emergency machine-cutting strategy generating module, used for solving the target function based on the power angle stability constraint condition and obtaining a target emergency machine-cutting strategy; The target emergency power-off strategy is used to instruct the wind-fire bundling and delivery system to cut off some non-faulty power generating sets.

9. A storage medium, characterized in that: The storage medium stores computer-readable instructions, and when the computer-readable instructions are executed by one or more processors, the one or more processors execute the steps of the emergency machine cutting method of the wind and fire baling 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, and when the computer-readable instructions are executed by the one or more processors, the steps of the emergency machine cutting method of the fire and air baling delivery system as described in any one of claims 1 to 7 are performed.

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