Optimization method and system of self-synchronous voltage source type new energy station and storage medium

Abstract

The application discloses a kind of self-synchronization voltage source type new energy field station optimization method, system and storage medium, and the present application determines high short-circuit ratio new energy field station and low short-circuit ratio new energy field station according to new energy field station short-circuit ratio, low short-circuit ratio new energy field station is set to self-synchronous voltage source mode operation, and the risk of low short-circuit ratio new energy field station is set to self-synchronous voltage source mode operation under the constraint of fault transient passive switching current source low wear control operation, based on current wind and light abandonment, to improve the key section transmission capability margin as target, optimize the power generation of self-synchronous voltage source mode operation new energy field station and standby capacity, can effectively improve the key section transmission capability margin of power grid, conducive to reducing new energy field station wind and light abandonment.

Description

Technical Field

[0001] This invention relates to an optimization method, system, and storage medium for self-synchronizing voltage source type renewable energy power stations, belonging to the field of power system and automation technology. Background Technology

[0002] The inverse distribution of resources and load demand dictates that large-scale, long-distance ultra-high voltage direct current (UHVDC) transmission is one of the dominant forms of large-scale wind power resource development and utilization. The high proportion of wind power integration at the UHVDC sending end leads to an increasingly weak grid structure at the sending end. System faults causing DC commutation failure, blocking, and restart can all result in transient AC overvoltages at the sending end, with commutation failure being the most severe. As near-field wind power output increases, the transient overvoltage situation under DC faults gradually worsens, leading to large-scale wind turbine overvoltage protection disconnection from the grid, severely restricting UHVDC transmission capacity and creating the operational contradiction of "the greater the wind power output, the smaller the DC transmission capacity." On the one hand, the larger the DC transmission power, the greater the reactive power consumed during normal DC operation, the more reactive power surplus after commutation failure, the more severe the near-area transient overvoltage, and the greater the probability of wind turbines disconnecting from the grid. On the other hand, the larger the grid-connected capacity of wind turbines, the fewer near-area thermal power plants will be turned on, the weaker the support of the sending-end system, and the lower the DC power transmission under transient overvoltage constraints.

[0003] There is a mutually restrictive relationship between DC transmission capacity and renewable energy absorption capacity. From the perspective of DC engineering, the reactive power demand under steady-state DC operation can be met by deploying a corresponding number of filters. However, the switching characteristics of filters mean they cannot provide flexible dynamic reactive power support during transient AC / DC disturbances in the power grid. To address this issue, current measures involve configuring appropriate capacity synchronous condensers near the DC transmission end for dynamic reactive power compensation, thereby improving the voltage support capacity of the DC transmission system. From the perspective of the system's ability to withstand disturbances, renewable energy lacks the active support function of the power grid and cannot provide sufficient support capacity like conventional thermal power units. The large-scale replacement of conventional thermal power units by renewable energy has led to a continuous decline in the strength of the transmission system, weakening its ability to withstand short-term power surges caused by DC commutation failures. Therefore, the current power grid has insufficient transmission capacity margin at key sections, and energy plants experience high levels of wind and solar curtailment. Summary of the Invention

[0004] This invention provides an optimization method, system, and storage medium for self-synchronizing voltage source type renewable energy power stations, solving the problems disclosed in the background art.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] Optimization methods for self-synchronizing voltage source type renewable energy power plants include:

[0007] Based on the short-circuit ratio of the renewable energy power plants, high short-circuit ratio renewable energy power plants and low short-circuit ratio renewable energy power plants are identified, and low short-circuit ratio renewable energy power plants are set to operate in self-synchronizing voltage source mode; among them, high short-circuit ratio renewable energy power plants are renewable energy power plants with a short-circuit ratio not lower than a threshold, and low short-circuit ratio renewable energy power plants are renewable energy power plants with a short-circuit ratio lower than a threshold.

[0008] Assess the risk of high short-circuit ratio renewable energy power plants operating in self-synchronizing voltage source mode, and set high short-circuit ratio renewable energy power plants with risk less than the threshold value to operate in self-synchronizing voltage source mode; the risk is the risk of transient passive switching to current source low-through control operation under constrained fault conditions.

[0009] For renewable energy power plants operating in self-synchronous voltage source mode, based on the current amount of wind and solar power curtailment, the power generation and reserve capacity of renewable energy power plants are optimized with the goal of improving the transmission capacity margin of key sections.

[0010] Before determining whether a renewable energy power station has a high short-circuit ratio or a low short-circuit ratio, the process includes calculating the short-circuit ratio of the renewable energy power station. The formula for calculating the short-circuit ratio of the renewable energy power station in this step is as follows:

[0011]

[0012] Among them, K ESCR，i S represents the short-circuit ratio of the new energy power station i. ki For the short-circuit capacity of new energy power station i, P i For the active power contribution of the new energy power station i, P j Let j be the active power output of the renewable energy power station, and n be the number of renewable energy power stations. Let z be the voltage interaction coefficient between renewable energy power station j and renewable energy power station i. ii For the self-impedance of the new energy power station, z ji Let be the mutual impedance between the new energy power station j and the i-th new energy power station i.

[0013] Assess the risks of high short-circuit ratio renewable energy power plants operating in self-synchronizing voltage source mode, and set high short-circuit ratio renewable energy power plants with risks below a threshold to operate in self-synchronizing voltage source mode, including:

[0014] Assess the terminal voltage level of renewable energy power plants with high short-circuit ratios under constrained fault conditions;

[0015] Based on the transient operating characteristics of self-synchronizing voltage source units, an interval distribution diagram of transient operating modes of self-synchronizing voltage source units under different overcurrent capacity levels is drawn.

[0016] Based on the current output, terminal voltage level, and interval distribution map of high short-circuit ratio renewable energy power plants, assess the risk of operating high short-circuit ratio renewable energy power plants in self-synchronization voltage source mode, and set high short-circuit ratio renewable energy power plants with risk below the threshold value to operate in self-synchronization voltage source mode.

[0017] Assess the terminal voltage level of renewable energy power plants with high short-circuit ratios under constrained fault conditions, including:

[0018] Calculate the electrical distance from the terminal node of a high short-circuit ratio new energy power station to the constrained fault point;

[0019] Based on the electrical distance, calculate the influence factor of constrained fault points on the terminal node voltage of new energy power plants with high short-circuit ratios;

[0020] Based on the influencing factors, assess the terminal voltage level of new energy power plants with high short-circuit ratios.

[0021] The formula for calculating the impact factor is:

[0022]

[0023] Among them, S i1-j1 To constrain the influence factor of fault point j1 on the voltage of node i1 at the generator terminal of new energy power plants with high short-circuit ratio, Z i1j1 I is the electrical distance from the high short-circuit ratio new energy power station terminal node i1 to the constrained fault point j1. ki1 This represents the short-circuit current of node i1 at the high short-circuit ratio new energy power station terminal.

[0024] The formula for assessing the terminal voltage level of high short-circuit ratio renewable energy power plants is:

[0025] V i1 ′=V i1 -S i1-j1 ΔV j1

[0026] Among them, V i1 ′ represents the transient voltage after a fault at node i1 of the high short-circuit ratio renewable energy power station, V. i1 For the high short-circuit ratio new energy power station terminal node i1 before the fault voltage, S i1-j1 To constrain the influence factor of fault point j1 on the voltage of terminal node i1 of new energy power plants with high short-circuit ratio, ΔV j1 To constrain the voltage change before and after the fault at fault point j1.

[0027] Based on the transient operating characteristics of self-synchronizing voltage source units, interval distribution diagrams of transient operating modes of self-synchronizing voltage source units under different overcurrent capacity levels are drawn, including:

[0028] Based on the transient operating characteristics of self-synchronizing voltage source units, the switching boundary voltage of transient operating modes of self-synchronizing voltage source units under different overcurrent capacity levels is determined.

[0029] Based on the switching boundary voltage, determine the interval distribution of the transient operation mode of the self-synchronizing voltage source unit and draw the interval distribution diagram.

[0030] The formula for calculating the switching boundary voltage is:

[0031]

[0032] Where U is the switching boundary voltage, k v U is the reactive voltage droop factor for self-synchronizing voltage source units. N P is the rated phase voltage amplitude of the self-synchronizing voltage source unit. e For the active power of the self-synchronizing voltage source unit, S is the rated phase current of the self-synchronizing voltage source unit. N For the rated capacity of the self-synchronizing voltage source unit, U LN is the rated line voltage of the self-synchronizing voltage source unit, and m is the overcurrent capacity coefficient of the self-synchronizing voltage source unit.

[0033] The optimization system for self-synchronizing voltage source type renewable energy power plants includes:

[0034] The short-circuit ratio module is used to determine whether a new energy power plant has a high short-circuit ratio or a low short-circuit ratio based on its short-circuit ratio, and to set the low short-circuit ratio new energy power plant to operate in self-synchronizing voltage source mode. Among them, a high short-circuit ratio new energy power plant is a new energy power plant with a short-circuit ratio not lower than a threshold, and a low short-circuit ratio new energy power plant is a new energy power plant with a short-circuit ratio lower than a threshold.

[0035] The assessment module is used to evaluate the risk of high short-circuit ratio renewable energy power plants operating in self-synchronizing voltage source mode, and sets high short-circuit ratio renewable energy power plants with risk less than the threshold value to operate in self-synchronizing voltage source mode; where risk is the risk of transient passive switching to current source low-through control operation under constrained faults;

[0036] The optimization module is designed for renewable energy power plants operating in self-synchronous voltage source mode. Based on the current amount of wind and solar power curtailment at the renewable energy power plant, it aims to improve the transmission capacity margin of key sections and optimize the power generation and reserve capacity of the renewable energy power plant.

[0037] The evaluation module includes:

[0038] The voltage assessment module is used to assess the terminal voltage level of new energy power plants with high short-circuit ratios under constrained fault conditions.

[0039] The interval distribution map module is used to draw interval distribution maps of the transient operation modes of the self-synchronized voltage source unit under different overcurrent capacity levels based on the transient operation characteristics of the self-synchronized voltage source unit.

[0040] The risk assessment module is used to assess the risk of high short-circuit ratio renewable energy power plants operating in self-synchronizing voltage source mode based on their current output, terminal voltage level, and interval distribution map. High short-circuit ratio renewable energy power plants with a risk less than the threshold value are set to operate in self-synchronizing voltage source mode.

[0041] The voltage evaluation module includes:

[0042] The electrical distance module is used to calculate the electrical distance between the terminal node of a new energy power station with a high short-circuit ratio and the constrained fault point.

[0043] The Influence Factor module is used to calculate the influence factor of constrained fault points on the terminal node voltage of new energy power plants with high short-circuit ratios, based on electrical distance.

[0044] The generator terminal voltage module is used to assess the generator terminal voltage level of new energy power plants with high short-circuit ratios based on influencing factors.

[0045] The interval distribution map module includes:

[0046] The switching boundary voltage module is used to determine the switching boundary voltage of the transient operation mode of the self-synchronous voltage source unit under different overcurrent capacity levels, based on the transient operation characteristics of the self-synchronous voltage source unit.

[0047] The drawing module is used to determine the interval distribution of the transient operation mode of the self-synchronizing voltage source unit based on the switching boundary voltage, and to draw the interval distribution diagram.

[0048] A computer-readable storage medium storing one or more programs, the one or more programs including instructions that, when executed by a computing device, cause the computing device to perform an optimization method for a self-synchronizing voltage source type renewable energy power station.

[0049] A computing device includes one or more processors, one or more memories, and one or more programs, wherein the one or more programs are stored in the one or more memories and configured to be executed by the one or more processors, and the one or more programs include instructions for performing an optimization method for a self-synchronizing voltage source type renewable energy power station.

[0050] The beneficial effects achieved by this invention are as follows: Based on the short-circuit ratio of renewable energy power plants, this invention determines renewable energy power plants with high and low short-circuit ratios. Renewable energy power plants with low short-circuit ratios are set to operate in self-synchronizing voltage source mode. Renewable energy power plants with high short-circuit ratios, which have a low risk of transient passive switching to current source low-throughput control under constrained faults, are also set to operate in self-synchronizing voltage source mode. Based on the current amount of wind and solar curtailment, and with the goal of improving the transmission capacity margin of key sections, the power generation and reserve capacity of renewable energy power plants operating in self-synchronizing voltage source mode are optimized. This can effectively improve the transmission capacity margin of key sections of the power grid and help reduce the amount of wind and solar curtailment at renewable energy power plants. Attached Figure Description

[0051] Figure 1 This is a flowchart of the method of the present invention;

[0052] Figure 2 This is a WSCC 9-node simulation system.

[0053] Figure 3 This is a voltage response curve under fault conditions.

[0054] Figure 4 This is a distribution chart of intervals. Detailed Implementation

[0055] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0056] like Figure 1 As shown, the optimization method for self-synchronizing voltage source type renewable energy power plants includes the following steps:

[0057] Step 1: Based on the short-circuit ratio of the new energy power plants, determine the new energy power plants with high short-circuit ratio and low short-circuit ratio, and set the new energy power plants with low short-circuit ratio to operate in self-synchronizing voltage source mode; wherein, the new energy power plants with high short-circuit ratio are new energy power plants with a short-circuit ratio not lower than the threshold, and the new energy power plants with low short-circuit ratio are new energy power plants with a short-circuit ratio lower than the threshold.

[0058] Step 2: Assess the risk of high short-circuit ratio renewable energy power plants operating in self-synchronizing voltage source mode, and set high short-circuit ratio renewable energy power plants with risk less than the threshold value to operate in self-synchronizing voltage source mode; where the risk is the risk of transient passive switching to current source low-through control operation under constrained faults;

[0059] Step 3: For renewable energy power plants operating in self-synchronous voltage source mode, based on the current amount of wind and solar power curtailment at the renewable energy power plants, optimize the power generation and reserve capacity of the renewable energy power plants with the goal of improving the transmission capacity margin of key sections.

[0060] The above method is applied to the power system control system to assist in the decision-making of grid operation mode. Based on the short-circuit ratio of renewable energy power plants, this method identifies renewable energy power plants with high and low short-circuit ratios. Renewable energy power plants with low short-circuit ratios are set to operate in self-synchronizing voltage source mode. Renewable energy power plants with high short-circuit ratios, which have low risk of transient passive switching to current source low-throughput control under constrained faults, are set to operate in self-synchronizing voltage source mode. Based on the current amount of wind and solar curtailment, with the goal of improving the transmission capacity margin of key sections, the method optimizes the power generation and reserve capacity of renewable energy power plants operating in self-synchronizing voltage source mode. This can effectively improve the transmission capacity margin of key sections of the grid and help reduce the amount of wind and solar curtailment at renewable energy power plants.

[0061] The short-circuit ratio of a renewable energy power plant characterizes the grid strength at the renewable energy connection point. A self-synchronizing voltage source connected to a weak grid operates stably, as does a current source connected to a strong grid. A renewable energy power plant with a high short-circuit ratio is defined as one with a short-circuit ratio not lower than a threshold, while a renewable energy power plant with a low short-circuit ratio is defined as one with a short-circuit ratio lower than the threshold.

[0062] When comparing new energy power plants with high and low short-circuit ratios, the short-circuit ratio of the new energy power plant should be calculated first, using the following formula:

[0063]

[0064] Among them, K ESCR，i S represents the short-circuit ratio of the new energy power station i. ki For the short-circuit capacity of new energy power station i, P i For the active power contribution of the new energy power station i, P j Let j be the active power output of the new energy power station, and n be the number of new energy power stations.

[0065]

[0066] Where, r ji Let ΔV be the voltage interaction coefficient between renewable energy power station j and renewable energy power station i. j ΔV i These represent the voltage changes of new energy power station j and new energy power station i, respectively, and z ii For the self-impedance of the new energy power station, z ji Let be the mutual impedance between the new energy power station j and the i-th new energy power station i.

[0067] Low short-circuit ratio renewable energy power plants will be set to operate in self-synchronizing voltage source mode. For high short-circuit ratio renewable energy power plants, further evaluation is needed. Specifically, the risks of operating high short-circuit ratio renewable energy power plants in self-synchronizing voltage source mode will be assessed, including the risk of transient passive switching to current source low-through-time control operation under constrained fault conditions. The specific assessment process can be as follows:

[0068] 1) Assess the generator terminal voltage level of a renewable energy power station with a high short-circuit ratio under constrained fault conditions. The process includes:

[0069] 11) Calculate the electrical distance between the terminal node of a high short-circuit ratio new energy power station and the constrained fault point;

[0070] The formula for calculating electrical distance is as follows:

[0071] Z i1j1 =z i1i1 +z j1j1 -z i1j1 -z j1i1

[0072] Among them, Z i1j1 The electrical distance from the high short-circuit ratio new energy power station terminal node i1 to the constrained fault point j1 is z. i1i1 For high short-circuit ratio renewable energy power stations, i1 self-impedance, z j1j1 For high short-circuit ratio renewable energy power stations, j1 self-impedance, z i1j1 For the mutual impedance of high short-circuit ratio new energy power station terminal node i1 and constrained fault point j1, z j1i1 To constrain the mutual impedance between fault point j1 and high short-circuit ratio new energy power station terminal node i1.

[0073] Electrical distance can measure the tightness of electrical connections between nodes. The smaller the electrical distance between nodes, the tighter the electrical connections in the system and the more branches in operation. Conversely, the sparser the network, the more branches are out of service in the system.

[0074] 12) Based on the electrical distance, calculate the influence factor of the constrained fault point on the terminal node voltage of the high short-circuit ratio renewable energy power station. The formula used can be:

[0075]

[0076] Among them, S i1-j1 To constrain the influence factor of fault point j1 on the voltage of node i1 at the generator terminal of new energy power plants with high short-circuit ratio, Z i1j1 I is the electrical distance from the high short-circuit ratio new energy power station terminal node i1 to the constrained fault point j1. ki1 This represents the short-circuit current of node i1 at the high short-circuit ratio new energy power station terminal.

[0077] 13) Based on the influencing factors, the formula used to assess the terminal voltage level of high short-circuit ratio renewable energy power stations can be:

[0078] V i1 ′=V i1 -S i1-j1 ΔV j1

[0079] Among them, Vi1 ′ represents the transient voltage after a fault at node i1 of the high short-circuit ratio renewable energy power station, V. i1 For high short-circuit ratio renewable energy power station terminal node i1 before fault, ΔV j1 To constrain the voltage change before and after the fault at fault point j1.

[0080] To verify the correctness of the voltage assessment method for new energy power plant terminals, a simulation model was established in the PSASP software as follows: Figure 2 The WSCC 9-node simulation system shown verifies the correctness of the theoretical results through simulation. Preset voltage dip fault types can include AC line three-terminal N-1 faults, three-terminal N-2 faults, etc. Initially, in the current mode, the load is 315MW, the load model is a constant impedance model, the renewable energy output is 106MW, all renewable energy units are doubly-fed wind turbines, there are 3 conventional units, each with a rated power of 300MW, and the inertial time constant of each generator is 2.93s, for a total output of 212MW, denoted as Mode 1. Assuming the fault location is a bus ground fault at STNA-230, the voltage at node A drops to 0.5pu for 0.1s, then immediately recovers to approximately 1.0pu; the short-circuit current at node A is 2.054kA. The equivalent reactance, short-circuit current, and voltage influence factor results for the current mode are shown in Table 1.

[0081] Table 1 Results of Equivalent Reactance, Short-Circuit Current, and Voltage Influence Factors under Current Method

[0082]

[0083] The voltage dip depth and recovery time at the fault point are used to assess the system load and the voltage dip and recovery time at the new energy node. The results are as follows: Figure 3 As shown, the results indicate that the voltage response curve obtained by the above voltage evaluation method is highly consistent with the voltage curve obtained by simulation calculation, indicating that the above evaluation is correct.

[0084] 2) Based on the transient operating characteristics of the self-synchronizing voltage source unit, draw the interval distribution diagram of the transient operating modes of the self-synchronizing voltage source unit under different overcurrent capacity levels. The process includes:

[0085] 21) Based on the transient operating characteristics of the self-synchronizing voltage source unit, determine the switching boundary voltage of the transient operating mode of the self-synchronizing voltage source unit under different overcurrent capacity levels.

[0086] First, based on the rated capacity and rated line voltage of the self-synchronizing voltage source unit, the rated phase current of the self-synchronizing voltage source unit can be calculated using the following formula:

[0087]

[0088] Among them, I NS is the rated phase current of the self-synchronizing voltage source unit. N For the rated capacity of the self-synchronizing voltage source unit, U LN This is the rated line voltage of the self-synchronizing voltage source unit.

[0089] Then, based on the reactive voltage droop coefficient of the self-synchronizing voltage source unit, the reactive power output of the self-synchronizing voltage source unit after voltage change is calculated. The calculation formula is as follows:

[0090] Q e -Q0=k v (U N -U)

[0091] Where U is the switching boundary voltage, k v U is the reactive voltage droop factor for self-synchronizing voltage source units. N Q represents the rated phase voltage amplitude of the self-synchronizing voltage source unit. e Q0 represents the actual reactive power output of the self-synchronizing voltage source unit, and Q0 is the reactive power command value of the self-synchronizing voltage source unit, which is generally set to 0var.

[0092] Based on the above calculation formulas for rated phase current, reactive power output, and actual phase voltage, as well as the relationship between apparent power and voltage-current, the operating mode switching boundary voltage under different overcurrent capabilities of the self-synchronizing voltage source can be calculated using the following formula:

[0093]

[0094] Among them, P e Let be the active power of the self-synchronizing voltage source unit, and m be the overcurrent capacity coefficient of the self-synchronizing voltage source unit.

[0095] 22) Based on the switching boundary voltage, determine the interval distribution of the transient operation mode of the self-synchronizing voltage source unit and draw the interval distribution diagram.

[0096] To verify the above method, the switching boundary voltages of the self-synchronizing voltage source unit under overcurrent capacities of 1.2 times, 1.5 times, and 2.0 times the rated current were calculated, and the interval distribution diagram was theoretically drawn.

[0097] Among them, U N 311v, k v 500 var / v, S N 50kVA;

[0098]

[0099]

[0100] When the overcurrent capability of the self-synchronizing voltage source is 1.2 times the rated current and the active power output is 1.0 pu, the formula for calculating the terminal voltage of the self-synchronizing voltage source is as follows:

[0101]

[0102] After standardization, it is 0.884 pu.

[0103] Based on the rated current of the self-synchronizing voltage source unit, the distribution of transient operating modes of the self-synchronizing voltage source unit under different terminal voltages and different outputs is analyzed.

[0104] When the overcurrent capacity is 1.2 times, 1.5 times, and 2.0 times the rated current, and the active power output of the self-synchronizing voltage source unit is 1.0 pu, 0.8 pu, 0.6 pu, 0.4 pu, and 0.2 pu, respectively, the terminal voltages of the self-synchronizing voltage source unit are shown in Tables 2, 3, and 4 below:

[0105] Table 2 shows the overcurrent capacity of the self-synchronizing voltage source unit is 1.2 times the rated current.

[0106]

[0107] Table 3 shows the overcurrent capacity of the self-synchronizing voltage source unit is 1.5 times the rated current.

[0108]

[0109] Table 4 shows the overcurrent capacity of the self-synchronizing voltage source unit is 2.0 rated current.

[0110]

[0111]

[0112] Based on the data in Tables 2-4, the transition boundary voltage curves of the self-synchronizing voltage source unit under different overcurrent energies were fitted, as follows: Figure 4 As shown, the operating mode range of the self-synchronizing voltage source is defined based on the switching boundary voltage curve.

[0113] 3) Based on the current output, terminal voltage level, and interval distribution diagram of the high short-circuit ratio renewable energy power plants, assess the risk of operating the high short-circuit ratio renewable energy power plants in self-synchronizing voltage source mode.

[0114] In the assessment results, new energy power plants with high short-circuit ratios and risks below the threshold will be set to operate in self-synchronizing voltage source mode.

[0115] For all renewable energy power plants operating in self-synchronizing voltage source mode, the current amount of wind and solar curtailment is assessed. This involves preprocessing the data characteristics of the daily power curves of wind and solar power generation, applying a wide-range learning neural network to predict renewable energy power generation, and then assessing the current amount of wind and solar curtailment based on the predicted renewable energy power generation and the actual output of the renewable energy units. Simultaneously, the current transmission capacity margin of key sections is calculated. Based on the current amount of wind and solar curtailment, the power generation and reserve capacity of renewable energy power plants are optimized with the goal of improving the transmission capacity margin of key sections.

[0116] The above method calculates the short-circuit ratio of new energy power plants and assesses the risk of switching self-synchronized voltage source type new energy power plants to current source low-through operation mode. It sets the initial operation mode of new energy power plants, optimizes the allocation of self-synchronized voltage source power generation and reserve capacity, improves the transmission capacity margin of key sections of the system, and reduces the amount of wind and solar power curtailment.

[0117] Based on the same technical solution, this invention also discloses a software system for the above-mentioned method, an optimization system for self-synchronizing voltage source type new energy power stations, comprising:

[0118] The short-circuit ratio module is used to determine whether a new energy power plant has a high short-circuit ratio or a low short-circuit ratio, and to set the low short-circuit ratio new energy power plant to operate in self-synchronizing voltage source mode. Among them, a high short-circuit ratio new energy power plant is a new energy power plant with a short-circuit ratio not lower than a threshold, and a low short-circuit ratio new energy power plant is a new energy power plant with a short-circuit ratio lower than a threshold.

[0119] The assessment module is used to evaluate the risk of high short-circuit ratio renewable energy power plants operating in self-synchronizing voltage source mode. High short-circuit ratio renewable energy power plants with risk less than a threshold value are set to operate in self-synchronizing voltage source mode. The risk is the risk of transient passive switching to current source low-through control operation under constrained fault conditions.

[0120] The evaluation module includes:

[0121] The voltage assessment module is used to assess the terminal voltage level of new energy power plants with high short-circuit ratios under constrained fault conditions.

[0122] The voltage evaluation module includes:

[0123] The electrical distance module is used to calculate the electrical distance between the terminal node of a new energy power station with a high short-circuit ratio and the constrained fault point.

[0124] The Influence Factor module is used to calculate the influence factor of constrained fault points on the terminal node voltage of new energy power plants with high short-circuit ratios, based on electrical distance.

[0125] The generator terminal voltage module is used to assess the generator terminal voltage level of new energy power plants with high short-circuit ratios based on influencing factors.

[0126] The interval distribution map module is used to draw interval distribution maps of the transient operation modes of self-synchronized voltage source units under different overcurrent capacity levels, based on the transient operation characteristics of the self-synchronized voltage source units.

[0127] The interval distribution map module includes:

[0128] The switching boundary voltage module is used to determine the switching boundary voltage of the transient operation mode of the self-synchronous voltage source unit under different overcurrent capacity levels, based on the transient operation characteristics of the self-synchronous voltage source unit.

[0129] The drawing module is used to determine the interval distribution of the transient operation mode of the self-synchronizing voltage source unit based on the switching boundary voltage, and to draw the interval distribution diagram.

[0130] The risk assessment module is used to assess the risk of high short-circuit ratio renewable energy power plants operating in self-synchronizing voltage source mode based on their current output, terminal voltage level, and interval distribution map. High short-circuit ratio renewable energy power plants with a risk less than the threshold value are set to operate in self-synchronizing voltage source mode.

[0131] The optimization module is designed for renewable energy power plants operating in self-synchronous voltage source mode. Based on the current amount of wind and solar power curtailment at the renewable energy power plant, it aims to improve the transmission capacity margin of key sections and optimize the power generation and reserve capacity of the renewable energy power plant.

[0132] Based on the same technical solution, the present invention also discloses a computer-readable storage medium storing one or more programs, the one or more programs including instructions, which, when executed by a computing device, cause the computing device to perform an optimization method for a self-synchronizing voltage source type new energy power station.

[0133] Based on the same technical solution, the present invention also discloses a computing device, including one or more processors, one or more memories, and one or more programs, wherein the one or more programs are stored in the one or more memories and configured to be executed by the one or more processors, and the one or more programs include instructions for executing an optimization method for a self-synchronizing voltage source type renewable energy power station.

[0134] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0135] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0136] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0137] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0138] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of the claims of the present invention pending approval.

Claims

1. An optimization method for self-synchronizing voltage source type renewable energy power stations, characterized in that, include: Based on the short-circuit ratio of the renewable energy power plants, high short-circuit ratio renewable energy power plants and low short-circuit ratio renewable energy power plants are identified, and low short-circuit ratio renewable energy power plants are set to operate in self-synchronizing voltage source mode; among them, high short-circuit ratio renewable energy power plants are renewable energy power plants with a short-circuit ratio not lower than a threshold, and low short-circuit ratio renewable energy power plants are renewable energy power plants with a short-circuit ratio lower than a threshold. Assess the risk of high short-circuit ratio renewable energy power plants operating in self-synchronizing voltage source mode, and set high short-circuit ratio renewable energy power plants with risk less than the threshold value to operate in self-synchronizing voltage source mode; the risk is the risk of transient passive switching to current source low-through control operation under constrained fault conditions. For renewable energy power plants operating in self-synchronous voltage source mode, based on the current amount of wind and solar power curtailment, the power generation and reserve capacity of renewable energy power plants are optimized with the goal of improving the transmission capacity margin of key sections.

2. The optimization method for self-synchronizing voltage source type new energy power stations according to claim 1, characterized in that, Before determining whether a renewable energy power station has a high short-circuit ratio or a low short-circuit ratio, the process includes calculating the short-circuit ratio of the renewable energy power station. The formula for calculating the short-circuit ratio of the renewable energy power station in this step is as follows: Among them, K ESCR，i S represents the short-circuit ratio of the new energy power station i. ki For the short-circuit capacity of new energy power station i, P i For the active power contribution of the new energy power station i, P j Let j be the active power output of the renewable energy power station, and n be the number of renewable energy power stations. Let z be the voltage interaction coefficient between renewable energy power station j and renewable energy power station i. ii For the self-impedance of the new energy power station, z ji Let be the mutual impedance between the new energy power station j and the i-th new energy power station i.

3. The optimization method for self-synchronizing voltage source type new energy power stations according to claim 1, characterized in that, Assess the risks of high short-circuit ratio renewable energy power plants operating in self-synchronizing voltage source mode, and set high short-circuit ratio renewable energy power plants with risks below a threshold to operate in self-synchronizing voltage source mode, including: Assess the terminal voltage level of renewable energy power plants with high short-circuit ratios under constrained fault conditions; Based on the transient operating characteristics of self-synchronizing voltage source units, an interval distribution diagram of transient operating modes of self-synchronizing voltage source units under different overcurrent capacity levels is drawn. Based on the current output, terminal voltage level, and interval distribution map of high short-circuit ratio renewable energy power plants, assess the risk of operating high short-circuit ratio renewable energy power plants in self-synchronization voltage source mode, and set high short-circuit ratio renewable energy power plants with risk below the threshold value to operate in self-synchronization voltage source mode.

4. The optimization method for self-synchronizing voltage source type new energy power stations according to claim 3, characterized in that, Assess the terminal voltage level of renewable energy power plants with high short-circuit ratios under constrained fault conditions, including: Calculate the electrical distance from the terminal node of a high short-circuit ratio new energy power station to the constrained fault point; Based on the electrical distance, calculate the influence factor of constrained fault points on the terminal node voltage of new energy power plants with high short-circuit ratios; Based on the influencing factors, assess the terminal voltage level of new energy power plants with high short-circuit ratios.

5. The optimization method for self-synchronizing voltage source type new energy power stations according to claim 4, characterized in that, The formula for calculating the impact factor is: Among them, S i1-j1 To constrain the influence factor of fault point j1 on the voltage of node i1 at the generator terminal of new energy power plants with high short-circuit ratio, Z i1j1 I is the electrical distance from the high short-circuit ratio new energy power station terminal node i1 to the constrained fault point j1. ki1 This represents the short-circuit current of node i1 at the high short-circuit ratio new energy power station terminal.

6. The optimization method for self-synchronizing voltage source type new energy power stations according to claim 4, characterized in that, The formula for assessing the terminal voltage level of high short-circuit ratio renewable energy power plants is: V i1 ′=V i1 -S i1-j1 ΔV j1 Among them, V i1 ′ represents the transient voltage after a fault at node i1 of the high short-circuit ratio renewable energy power station, V. i1 For the high short-circuit ratio new energy power station terminal node i1 before the fault voltage, S i1-j1 To constrain the influence factor of fault point j1 on the voltage of terminal node i1 of new energy power plants with high short-circuit ratio, ΔV j1 To constrain the voltage change before and after the fault at fault point j1.

7. The optimization method for self-synchronizing voltage source type new energy power stations according to claim 3, characterized in that, Based on the transient operating characteristics of self-synchronizing voltage source units, interval distribution diagrams of transient operating modes of self-synchronizing voltage source units under different overcurrent capacity levels are drawn, including: Based on the transient operating characteristics of self-synchronizing voltage source units, the switching boundary voltage of transient operating modes of self-synchronizing voltage source units under different overcurrent capacity levels is determined. Based on the switching boundary voltage, determine the interval distribution of the transient operation mode of the self-synchronizing voltage source unit and draw the interval distribution diagram.

8. The optimization method for self-synchronizing voltage source type new energy power stations according to claim 7, characterized in that, The formula for calculating the switching boundary voltage is: Where U is the switching boundary voltage, k v U is the reactive voltage droop factor for self-synchronizing voltage source units. N P is the rated phase voltage amplitude of the self-synchronizing voltage source unit. e For the active power of the self-synchronizing voltage source unit, S is the rated phase current of the self-synchronizing voltage source unit. N For the rated capacity of the self-synchronizing voltage source unit, U LN is the rated line voltage of the self-synchronizing voltage source unit, and m is the overcurrent capacity coefficient of the self-synchronizing voltage source unit.

9. An optimization system for a self-synchronizing voltage source type renewable energy power station, characterized in that, include: The short-circuit ratio module is used to determine whether a new energy power plant has a high short-circuit ratio or a low short-circuit ratio based on its short-circuit ratio, and to set the low short-circuit ratio new energy power plant to operate in self-synchronizing voltage source mode. Among them, a high short-circuit ratio new energy power plant is a new energy power plant with a short-circuit ratio not lower than a threshold, and a low short-circuit ratio new energy power plant is a new energy power plant with a short-circuit ratio lower than a threshold. The assessment module is used to evaluate the risk of high short-circuit ratio renewable energy power plants operating in self-synchronizing voltage source mode, and sets high short-circuit ratio renewable energy power plants with risk less than the threshold value to operate in self-synchronizing voltage source mode; where risk is the risk of transient passive switching to current source low-through control operation under constrained faults; The optimization module is designed for renewable energy power plants operating in self-synchronous voltage source mode. Based on the current amount of wind and solar power curtailment at the renewable energy power plant, it aims to improve the transmission capacity margin of key sections and optimize the power generation and reserve capacity of the renewable energy power plant.

10. The optimization system for a self-synchronizing voltage source type new energy power station according to claim 9, characterized in that, The evaluation module includes: The voltage assessment module is used to assess the terminal voltage level of new energy power plants with high short-circuit ratios under constrained fault conditions. The interval distribution map module is used to draw interval distribution maps of the transient operation modes of the self-synchronized voltage source unit under different overcurrent capacity levels based on the transient operation characteristics of the self-synchronized voltage source unit. The risk assessment module is used to assess the risk of high short-circuit ratio renewable energy power plants operating in self-synchronizing voltage source mode based on their current output, terminal voltage level, and interval distribution map. High short-circuit ratio renewable energy power plants with a risk less than the threshold value are set to operate in self-synchronizing voltage source mode.

11. The optimization system for a self-synchronizing voltage source type new energy power station according to claim 10, characterized in that, The voltage evaluation module includes: The electrical distance module is used to calculate the electrical distance between the terminal node of a new energy power station with a high short-circuit ratio and the constrained fault point. The Influence Factor module is used to calculate the influence factor of constrained fault points on the terminal node voltage of new energy power plants with high short-circuit ratios, based on electrical distance. The generator terminal voltage module is used to assess the generator terminal voltage level of new energy power plants with high short-circuit ratios based on influencing factors.

12. The optimization system for a self-synchronizing voltage source type new energy power station according to claim 10, characterized in that, The interval distribution map module includes: The switching boundary voltage module is used to determine the switching boundary voltage of the transient operation mode of the self-synchronous voltage source unit under different overcurrent capacity levels, based on the transient operation characteristics of the self-synchronous voltage source unit. The drawing module is used to determine the interval distribution of the transient operation mode of the self-synchronizing voltage source unit based on the switching boundary voltage, and to draw the interval distribution diagram.

13. A computer-readable storage medium storing one or more programs, characterized in that, The one or more programs include instructions that, when executed by a computing device, cause the computing device to perform any of the methods according to claims 1 to 8.

14. A computing device, characterized in that, It includes one or more processors, one or more memories, and one or more programs, wherein the one or more programs are stored in the one or more memories and configured to be executed by the one or more processors, and the one or more programs include instructions for performing any of the methods according to claims 1 to 8.

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