A method and system for synchronous estimation of multi-parameter deviations in new energy power plants

Abstract

This application discloses a synchronous estimation method and system for multi-parameter deviations in new energy power plants, belonging to the field of smart grid technology. The synchronous estimation method for multi-parameter deviations in new energy power plants includes: constructing a joint optimization objective function corresponding to each steady-state moment of the current operating period; the multi-parameter deviations include the measurement errors of each current transformer and the tap ratio deviations of each tap position of the on-load tap changer of the main transformer; solving the problem with minimizing the joint optimization objective function as the objective to obtain the synchronous estimation result of the multi-parameter deviations. This invention incorporates multiple parameters, including CT measurement errors and OLTC tap ratio deviations, into the joint optimization objective function for synchronous solution, fundamentally avoiding the problem of existing separate estimation methods absorbing another type of parameter deviation into the estimation result, eliminating parameter confusion interference, and significantly improving the identification accuracy of the two types of parameter deviations compared to existing methods.

Description

Technical Field

[0001] This application belongs to the field of smart grid technology, and more specifically, relates to a method and system for synchronous estimation of multi-parameter deviations in new energy power plants. Background Technology

[0002] Current transformers (CTs) are crucial equipment for acquiring current measurement information in new energy power plants. Their measurement errors directly affect the accuracy of current measurements in each branch and on both sides of the main transformer. On-load tap-changers (OLTCs) are used to adjust the transformer ratio. Deviations in their actual tap ratios affect the electrical correspondence between the high and low voltage sides of the main transformer. Therefore, both CT measurement errors and OLTC tap ratio deviations affect the accuracy of the associated measurements on both sides of the main transformer.

[0003] As the scale of renewable energy grid connection continues to expand, the requirements for the accuracy of measurement information and key equipment parameters in power system operation are constantly increasing. As a crucial link in power collection and conversion, the accuracy of measurement results and main equipment parameters in new energy power plants directly affects the operation monitoring, analysis, and control of the power system. Especially in new energy power plants, the on-load tap changers of main transformers operate frequently, sometimes dozens of times a day, and the redundancy of high-voltage side measurements within the plant is limited, placing higher demands on the accurate online identification of these two types of parameters.

[0004] In existing technologies, OLTC tap ratio deviation analysis relies on transformer ratio tests conducted under power outage conditions, which cannot reflect the real-time deviation status under operating conditions. While the power outage verification method for CT measurement errors has high accuracy, it cannot be carried out in real time and is costly and inefficient. Existing online monitoring methods only estimate CT measurement errors separately. In scenarios involving the interconnected measurement of the high and low voltage sides of the main transformer, when the measurement results on both sides are inconsistent with the electrical relationship they should satisfy, this inconsistency may be caused by CT measurement errors, OLTC tap ratio deviation, or a combination of both. If only one type of parameter is estimated separately, the deviation of the other type of parameter is easily absorbed into the current estimation result, leading to parameter confusion and ultimately affecting the accuracy of identification. Existing technologies cannot achieve online synchronous estimation of CT measurement errors and main transformer OLTC tap ratio deviation. Summary of the Invention

[0005] To address the aforementioned deficiencies or improvement needs of existing technologies, this application provides a method and system for synchronous estimation of multi-parameter deviations in new energy power plants, which solves the technical problem that existing technologies cannot achieve online synchronous estimation of CT measurement errors and main transformer OLTC tap ratio deviations.

[0006] To achieve the above objectives, according to one aspect of this application, a method for synchronous estimation of multi-parameter deviations within a new energy power plant is provided, comprising: S1: Determine all steady-state moments of the new energy power plant during its current operating period. and their corresponding gears ; S2: Construct the steady-state moments of the current runtime segment. Corresponding joint optimization objective function ; The vector of parameters to be estimated involved in the joint optimization solution includes: the measurement errors of each current transformer and the tap ratio deviations of each tap position of the on-load tap changer of the main transformer; the joint optimization objective function. Includes: the sum of the first objective function, the second objective function, and the third objective function; The first objective function includes: each steady-state time. Corresponding high-voltage side node current balance residual The average current of all branches on the high-voltage side, excluding the main branch, after error correction. The sum of ratios; the second objective function includes: the sum of ratios at each steady-state time. Corresponding low-voltage side node current balance residual The average current of all branches on the low-voltage side, excluding the main branch, after error correction. The sum of ratios; the third objective function includes: the sum of ratios at each steady-state time. and their corresponding gears Corresponding residuals of high and low voltage side currents of the main transformer The current after error correction of the low-voltage branch of the main transformer The sum of the ratios; S3: Using the joint optimization objective function The objective is to minimize the vector of parameters to be estimated. The synchronous estimation results.

[0007] Furthermore, the joint optimization objective function Represented as: ; in, , These represent the total number of current transformers in each branch of the high-voltage and low-voltage sides, excluding the main branch. , These are the currents of each branch on the high and low voltage sides, excluding the main branch, after error correction.

[0008] Furthermore, ; ; ; in, Represents the steady-state moment The current in the low-voltage branch of the main transformer after error correction. Represents the steady-state moment The current in the high-voltage branch of the main transformer after error correction. steady state time The voltage estimate after error correction for the low-voltage side bus voltage transformer. The excitation impedance of the main transformer's excitation branch. Represents the steady-state moment Corresponding gear The following is the estimated actual tapping ratio: ; Represents the steady-state moment Corresponding gear The rated tap ratio, Represents the steady-state moment Corresponding gear The tap ratio deviation.

[0009] Furthermore, the parameter vector to be estimated Represented as: ; in, This represents the ratio difference of each of the N current transformers. This represents the phase difference between N current transformers. Indicates the actual occurrence within the current runtime segment The tap ratio deviation of each gear; These represent the ratio difference and phase difference of the voltage transformer on the low-voltage side bus, respectively. These represent the real and imaginary parts of the excitation impedance corresponding to the excitation branch of the main transformer, respectively.

[0010] Further, S1 includes: S11: Collect the original operating dataset of the new energy plant during the current operating period; including: current measurement data of each branch on the high-voltage side of the main transformer, current measurement data of each branch on the low-voltage side of the main transformer, bus voltage measurement data, total number of tap ratio positions and tap range information of the main transformer. S12: Perform steady-state condition filtering on the original runtime dataset to obtain multiple steady-state moments. ; S13: For all steady-state moments The gear position recognition features are clustered or partitioned into intervals, and each steady-state moment is determined according to the partitioning results. corresponding gear .

[0011] Furthermore, the original running dataset mentioned in S11 Represented as: ; in, The measured value of the low-voltage branch current of the main transformer. The measured value of the high-voltage branch current of the main transformer. For the low-voltage side, excluding the main transformer branch, the The current measurements of each branch are total. One measurement branch; For the high-voltage side, excluding the main transformer branch, the The current measurements of each branch are total. One measurement branch; This is the measured value of the low-voltage side bus voltage; This is the measured value of the high-voltage side bus voltage.

[0012] Further, S12 includes: performing outlier removal on the original running dataset to obtain the dataset to be analyzed; if at a certain moment... The dataset to be analyzed satisfies: and , Then determine the time Corresponding to steady-state operating conditions and time steady state time ; For the entire current measurement sequence at time... The maximum normalized rate of change The high and low voltage side bus voltage measurement sequence at time 1 The maximum normalized rate of change The current steady-state criterion threshold, Voltage steady-state criterion threshold: ; ; For any measurement sequence Its maximum normalized rate of change is: , A positive number is set to prevent the denominator from being zero. It is the time before time t.

[0013] Furthermore, S13 includes: for all steady-state moments Corresponding gear recognition feature quantity The characteristic sequence constituted Perform cluster analysis or interval partitioning to identify the actual tap positions that occur within the current runtime. Establish each steady-state moment. With corresponding tap position The mapping relationship between them ; ; ; ; K represents all tap positions. The total number, steady state time Low-voltage side current polymerization amount, steady state time The corresponding high-voltage side current aggregation amount.

[0014] According to another aspect of this application, a synchronous estimation system for multi-parameter deviations within a new energy power plant is provided, comprising a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps of the synchronous estimation method for multi-parameter deviations within a new energy power plant.

[0015] According to another aspect of this application, a computer-readable storage medium is provided, on which a computer program is stored, wherein when the computer program is executed by a processor, the steps of the synchronous estimation method for multi-parameter deviations within the new energy power plant are implemented.

[0016] In summary, compared with the prior art, the above-described technical solutions conceived in this application can achieve the following beneficial effects: (1) This invention provides a method for synchronously estimating the deviation of multiple parameters in a new energy power plant, and constructs the steady-state time of each current operating period. Corresponding joint optimization objective function ; This represents the vector of parameters to be estimated involved in the joint optimization solution, among which the key estimated deviation parameters include: the measurement errors of each current transformer and the tap ratio deviations of each tap position of the on-load tap changer of the main transformer; the joint optimization objective function is... The objective is to minimize the vector of parameters to be estimated. The invention simultaneously incorporates multiple parameters, including CT measurement error and OLTC tap ratio deviation, into a joint optimization objective function for synchronous solution. This fundamentally avoids the problem of existing individual estimation methods absorbing another type of parameter deviation into the estimation results, eliminating parameter confusion and interference. Compared with existing methods, it can significantly improve the identification accuracy of the two types of parameter deviations. Only one optimization solution is needed to obtain the estimation results of the two types of parameters simultaneously, without repeated iterative calculation of different parameters. The calculation process is simpler, and the invention ultimately provides efficient and accurate online estimation of current transformer measurement error and on-load tap changer tap ratio deviation of the main transformer. It can be adapted to the application scenario of frequent on-load tap changer operation in new energy power plants and meets the computational performance requirements of real-time estimation.

[0017] (2) The joint optimization objective function described in this scheme Represented as: This design integrates the low-voltage side node current balance constraints, the high-voltage side node current balance constraints, and the high- and low-voltage side current correlation constraints of the main transformer into the same objective function. It also normalizes the residuals using the mean current of the corresponding side branch or the low-voltage branch current of the main transformer. This reduces the impact of the difference in magnitude of different residual terms on the optimization results and improves the stability and robustness of the joint solution.

[0018] (3) The residual current correlation between the high and low voltage sides of the main transformer in this scheme is: Steady-state moment Corresponding gear The estimated actual tap ratio is as follows: This design explicitly incorporates the actual tap ratio deviation of the on-load tap changer into the correlation between the high and low voltage currents of the main transformer, while also taking into account the influence of the excitation branch current. This allows for the separation of the effects of CT measurement error and tap ratio deviation, avoiding parameter confusion and improving identification accuracy and physical consistency.

[0019] (4) The parameter vector to be estimated in this scheme Represented as: This design focuses on the CT ratio difference, CT angle difference, and tap ratio deviation of each operating position as key multi-parameter deviations, and incorporates voltage transformer error parameters and excitation branch parameters as auxiliary parameters to be estimated into the optimization model. This approach can highlight the synchronous estimation results that this application is truly concerned with while ensuring the integrity of the model.

[0020] (5) In this scheme, the original operating dataset of the new energy plant during the current operating period is filtered for steady-state conditions to obtain multiple steady-state moments. For all steady-state moments The gear position recognition features are clustered or partitioned into intervals, and each steady-state moment is determined according to the partitioning results. corresponding gear This design allows for the elimination of non-steady-state disturbance data before establishing a clear 'time-gear' mapping relationship for each steady-state moment, thereby reducing the interference of transient processes and gear confusion on subsequent synchronization estimation.

[0021] (6) The original running dataset described in this scheme Represented as: This design allows for the simultaneous collection of branch currents, bus voltages, and tap parameters on both sides of the main transformer, providing a complete data foundation for constructing node current balance relationships, the correlation between the two sides of the main transformer, and tap position identification features, thereby ensuring that the synchronous estimation model is observable and feasible.

[0022] (7) In this scheme, if at a certain moment The dataset to be analyzed satisfies: and Then the time is determined Corresponding to steady-state operating conditions and time steady state time This design, by simultaneously constraining the normalized rate of change of current and bus voltage, can effectively identify and eliminate transient disturbances and unsteady-state samples during tap switching, ensuring that the data used for parameter estimation meets the steady-state assumptions and improving the accuracy and convergence stability of parameter estimation.

[0023] (8) In this scheme, for all steady-state moments Corresponding gear recognition feature quantity The characteristic sequence formed Cluster analysis or interval division is performed to construct the circuit. This design uses the proportional relationship between the current aggregation on both sides of the main transformer to identify the operating level, eliminating the need for power outage tests and additional hardware support, thus improving the feasibility of online applications. Attached Figure Description

[0024] Figure 1 This is a flowchart of a method for synchronously estimating multi-parameter deviations within a new energy power plant, provided in one embodiment of this application.

[0025] Figure 2 This is a schematic diagram illustrating the application environment of the synchronous estimation method for multi-parameter deviations within a new energy power plant provided in one embodiment of this application. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. Furthermore, the technical features involved in the various embodiments described below can be combined with each other as long as they do not conflict with each other.

[0027] Example 1 This embodiment provides a method for synchronous estimation of multi-parameter deviations within a new energy power plant, such as... Figure 1 As shown, it includes: S1-S3. See reference. Figure 2 In this embodiment of the invention, with the main transformer within the new energy power plant as the center, current transformers for measuring the inflow current on the low-voltage side and the outflow current on the high-voltage side of the main transformer are respectively configured on the low-voltage side branch and the high-voltage side branch. In addition to the main transformer branch, several collector line current transformers are also configured on the low-voltage side, and several transmission line current transformers are also configured on the high-voltage side. These current transformers, together with the high- and low-voltage side bus voltage transformers, constitute the basis for online measurement within the plant in this embodiment.

[0028] S1: Determine all steady-state moments of the new energy power plant during its current operating period. and their corresponding gears .

[0029] S2: Construct the steady-state moments of the current runtime segment. Corresponding joint optimization objective function ; This represents the vector of parameters to be estimated involved in the joint optimization solution, among which the key estimated deviation parameters include: the measurement errors of each current transformer and the tap ratio deviations of each tap position of the on-load tap changer of the main transformer; the joint optimization objective function... It includes the sum of the first objective function, the second objective function, and the third objective function.

[0030] The first objective function includes: each steady-state time. Corresponding high-voltage side node current balance residual The average current of all branches on the high-voltage side, excluding the main branch, after error correction. The sum of ratios; the second objective function includes: the sum of ratios at each steady-state time. Corresponding low-voltage side node current balance residual The average current of all branches on the low-voltage side, excluding the main branch, after error correction. The sum of ratios; the third objective function includes: the sum of ratios at each steady-state time. and their corresponding gears Corresponding residuals of high and low voltage side currents of the main transformer The current after error correction of the low-voltage branch of the main transformer The sum of the ratios; S3: Using the joint optimization objective function The objective is to minimize the vector of parameters to be estimated. The synchronous estimation results.

[0031] As an optional implementation, S1 includes: S11: collecting the original operating dataset of the new energy power plant during the current operating period; including: current measurement data of each branch on the high-voltage side of the main transformer, current measurement data of each branch on the low-voltage side of the main transformer, bus voltage measurement data, total number of tap positions and tap range information of the main transformer; S12: performing steady-state condition filtering on the original operating dataset to obtain multiple steady-state moments. S13: For all steady-state moments The gear position recognition features are clustered or partitioned into intervals, and each steady-state moment is determined according to the partitioning results. corresponding gear .

[0032] As an optional implementation, the original running dataset in S11 Represented as: ; in, The measured value of the low-voltage branch current of the main transformer. The measured value of the high-voltage branch current of the main transformer. For the low-voltage side, excluding the main transformer branch, the The current measurements of each branch are total. One measurement branch; For the high-voltage side, excluding the main transformer branch, the The current measurements of each branch are total. One measurement branch; This is the measured value of the low-voltage side bus voltage; This is the measured value of the high-voltage side bus voltage.

[0033] Specifically, focusing on the main transformer within the target new energy plant, relevant measurement data from the high-voltage and low-voltage sides of the main transformer were collected, along with tap parameters. The collected data included: low-voltage branch current measurement data, high-voltage branch current measurement data, low-voltage branch current measurement data (excluding the main transformer branch), high-voltage branch current measurement data (excluding the main transformer branch), low-voltage bus voltage measurement data, high-voltage bus voltage measurement data, the total number of tap positions and tap range information for the main transformer. For ease of description, the measured value of the low-voltage branch current is denoted as... The measured current value of the main transformer high-voltage branch is Among them, subscript Indicates the low-voltage branch of the main transformer, subscript Indicates the high-voltage branch of the main transformer, subscript This indicates the measured value.

[0034] Among them, the low-voltage side, excluding the main transformer branch, has a total of The first measurement branch, the first The current measurement value of each branch is ,in Assume that the high-voltage side has a total of [number] branches besides the main transformer branch. The first measurement branch, the first The current measurement value of each branch is ,in Record the measured value of the low-voltage side bus voltage. The measured value of the high-voltage side bus voltage is The total number of sampling times is , The original running dataset can then be represented as: ; At the same time, collect the total number of tap positions of the main transformer. Rated tap ratio for each gear And tap range information, among which The rated tap ratio for each gear can then be expressed as: ; in, The rated tap ratio for the center gear. The center slot number, For single-tap step sizes, relevant information about the main transformer can be obtained from the transformer nameplate. Through the above data collection, the original operational dataset required for subsequent steady-state screening, tap identification, and joint optimization solutions is constructed.

[0035] As an optional implementation, S12 includes: performing outlier removal on the original running dataset to obtain the dataset to be analyzed; if at a certain moment... The dataset to be analyzed satisfies: and , Then determine the time Corresponding to steady-state operating conditions and time steady state time ; For the entire current measurement sequence at time... The maximum normalized rate of change; The high and low voltage side bus voltage measurement sequence at time 1 Maximum normalized rate of change: ; .

[0036] For any measurement sequence Its maximum normalized rate of change is: , A very small positive number is set to prevent the denominator from being zero. It is the time before time t.

[0037] Specifically, because the raw measurement data may contain sampling spikes, transient disturbances, and non-steady-state data caused by on-load tap changer switching, directly using it for parameter estimation would reduce the accuracy and stability of synchronous estimation. Therefore, it is necessary to modify the raw operational dataset. Preprocessing is performed. Outlier removal is applied to the main transformer low-voltage branch current measurement sequences, the main transformer high-voltage branch current measurement sequences, the low-voltage side current measurement sequences (excluding the main branch), the high-voltage side current measurement sequences (excluding the main branch), and the high- and low-voltage side bus voltage measurement sequences. For any measurement sequence... The normalized rate of change for adjacent time steps is defined as: ; in, A very small positive number is used to prevent the denominator from being zero. For Sampling points that are significantly larger than the normal fluctuation range are identified as outliers and are replaced by adjacent steady-state samples or directly removed.

[0038] Steady-state condition screening is performed on the preprocessed data. Assume all current measurement sequences are at time [time value missing]. The maximum normalized rate of change is: ; Assume the high- and low-voltage bus voltage measurement sequences at time 10:00. The maximum normalized rate of change is: ; Given current steady-state criterion threshold Voltage steady-state criterion threshold At a certain moment Simultaneously satisfy: and ; If the current moment corresponds to a steady-state condition, then that moment is considered a transient condition and will not be included in subsequent synchronization estimation. To avoid data near the on-load tap changer switching boundary affecting tap position identification and parameter estimation, data before and after the identified switching moment is processed. All sampling points were removed. After outlier removal and steady-state filtering, the steady-state time series dataset was obtained: ; in, This is the set of steady-state moment numbers that have passed the screening. This is the preset rejection window length.

[0039] As an optional implementation, S13 includes: for all steady-state moments Corresponding gear recognition feature quantity The characteristic sequence constituted Perform cluster analysis or interval partitioning to identify the actual tap positions that occur within the current runtime. Establish each steady-state moment. With corresponding tap position The mapping relationship between them ; ; ; ; steady state time Low-voltage side current polymerization amount, steady state time The corresponding high-voltage side current aggregation amount.

[0040] Since there are different stable correspondences between the high and low voltage side current measurements of the main transformer under different operating positions, the operating position identification feature quantity can be constructed based on the high and low voltage side current measurement data under steady-state conditions, and the corresponding operating position at each time can be identified accordingly.

[0041] For any steady-state moment The current aggregation amounts on the low-voltage side and the high-voltage side are defined as follows: ; ; Based on the above aggregation, a gear position recognition feature quantity is constructed. : ; in, Used to characterize the proportional relationship between the aggregated currents on both sides of the main transformer.

[0042] The gear identification features corresponding to all steady-state moments are combined into a feature sequence: ; for characteristic sequences Cluster analysis or interval partitioning is performed to identify the different tap positions actually occurring within the current runtime. Preferably, K-means clustering, hierarchical clustering, or density clustering methods can be used to segment the feature sequences. Divided into Each feature cluster is analyzed, and the center value of each feature cluster is obtained. ,in ,and , This represents the actual number of running gears occurring within the current runtime segment. Based on the center values ​​of each feature cluster. The size relationship and the rated tap ratio sequence of each gear Based on the monotonic correspondence, establish a mapping relationship of "feature cluster - gear number", and then obtain the mapping relationship of "time - gear": ;in, Represents the steady-state moment The corresponding gear number, and .

[0043] Based on mapping relationship The steady-state time series dataset Divided into time series data subsets corresponding to each gear level: ;in, This refers to the actual operating gear number that occurred during the current analysis period.

[0044] As an optional implementation, the parameter vector to be estimated Represented as: ; in, This represents the ratio difference of each of the N current transformers. This represents the phase difference between N current transformers. Indicates the actual occurrence within the current runtime segment The tap ratio deviation of each gear; These represent the ratio difference and phase difference of the voltage transformer on the low-voltage side bus, respectively. These represent the real and imaginary parts of the excitation impedance corresponding to the excitation branch of the main transformer, respectively. The auxiliary parameters to be estimated, which are introduced to construct the joint optimization objective function and improve the accuracy of synchronous estimation, are the current transformer measurement error parameters and the tap ratio deviation parameters, which are the multi-parameter deviations of interest in this application.

[0045] Construction of the parameter set to be estimated. After completing the gear position identification, the parameter set required for synchronous estimation is constructed. The current transformers involved in the estimation include: the low-voltage branch CT of the main transformer, the high-voltage branch CT of the main transformer, the CTs of all branches on the low-voltage side except the main branch, and the CTs of all branches on the high-voltage side except the main branch. Let the total number of current transformers involved in the synchronous estimation be... ,but: ; For the A current transformer, whose ratio difference is denoted as . Angular difference is For the first occurrence actually occurring within the current runtime segment Each gear has a tap ratio deviation of [value missing]. Meanwhile, considering the parameters of the main transformer excitation branch, the excitation impedance is denoted as: ; in, This represents the real part of the magnetizing impedance. This represents the imaginary part of the excitation impedance.

[0046] For the low-voltage side bus voltage transformer, its ratio difference is denoted as... Angular difference is Then the parameter vector to be estimated It can be represented as: ; in, This represents the actual number of gears that occur during the current runtime segment.

[0047] As an optional implementation method, ; ; ;in, Represents the steady-state moment The current in the low-voltage branch of the main transformer after error correction. Represents the steady-state moment The current in the high-voltage branch of the main transformer after error correction. steady state time The voltage estimate after error correction for the low-voltage side bus voltage transformer. The excitation impedance of the main transformer's excitation branch. Represents the steady-state moment Corresponding gear The following is the estimated actual tapping ratio: ; Represents the steady-state moment Corresponding gear The rated tap ratio, Represents the steady-state moment Corresponding gear The tap ratio deviation.

[0048] For any steady-state moment , No. Error-corrected current estimate of a current transformer Defined as: ; in, For the first A current transformer at time The measured current value. For any operating setting. Its actual tap ratio is defined as: ; in, For the first Rated tap ratio, For the first Gear segmentation ratio deviation.

[0049] For any steady-state moment The voltage estimate after error correction of the low-voltage side bus voltage transformer Defined as: ; The joint optimization objective function is constructed. The joint optimization objective consists of the residuals of the low-voltage side node current balance, the residuals of the high-voltage side node current balance, and the residuals of the correlation between the high-voltage and low-voltage sides of the main transformer current.

[0050] First, construct the low-voltage side node current balance residual. Based on the preset current reference direction, assume the current in the main transformer's low-voltage branch after error correction is... The current on the low-voltage side, excluding the main branch, after error correction, is: The residual current balance at the low-voltage side node can then be expressed as: .

[0051] Second, construct the high-voltage side node current balance residual. Based on the preset current reference direction, assume the current in the main transformer high-voltage branch after error correction is... The current on the high-voltage side, excluding the main branch, after error correction, is: The residual current balance at the high-voltage side node can then be expressed as: .

[0052] Third, construct the current correlation residuals between the high and low voltage sides of the main transformer. After uniformly converting the currents on both sides of the main transformer to the same side and completing phase compensation according to the main transformer's connection group, the current correlation residuals between the high and low voltage sides of the main transformer can be expressed as: ; in, For a moment The actual tap ratio at the corresponding gear position. This is the excitation current term.

[0053] As an optional implementation, the joint optimization objective function Represented as: ; in, , These represent the total number of CTs in each branch except the main branch on the high- and low-pressure sides, respectively. , These represent the currents of each branch on the high and low voltage sides, excluding the main branch, after error correction. The denominator is the normalized term for each residual term. This represents the summation over all steady-state moments.

[0054] Search space settings. The search space settings for each parameter to be estimated are as follows: ; ; ; ; ; ; ; in, and This refers to the allowable range of ratio error for current transformers at the corresponding accuracy class. and This refers to the allowable range of current transformer angle difference under the corresponding accuracy class. The allowable range for the tap ratio deviation of the main transformer, according to GB / T1094.1-2013 "Power Transformers Part 1: General Rules", is taken as 0.5%. and This refers to the allowable range of voltage transformer ratio error under the corresponding accuracy class. and This refers to the allowable range of voltage transformer angle difference under the corresponding accuracy class. and This is the nominal value of the excitation impedance. The allowable fluctuation ratio of the excitation impedance is 1%, and a value of 1% is recommended.

[0055] Furthermore, since the constructed joint optimization problem simultaneously includes measurement error parameters of multiple branch current transformers, tap ratio deviation parameters corresponding to multiple operating positions, and excitation impedance parameters, and the objective function is nonlinear, an optimization algorithm is used to solve it. Preferably, differential evolution algorithm, multi-operator improved differential evolution algorithm, particle swarm optimization algorithm, genetic algorithm, etc., can be used for solving it.

[0056] The optimization termination condition is: objective function The decrease in the magnitude of two consecutive iterations is less than a preset threshold. or reaching the maximum number of iterations. If the iteration stops, the optimal parameter estimation result is output. This enables the synchronous estimation of the measurement error of the current transformer in the new energy power plant and the deviation of the on-load tap changer ratio of the main transformer.

[0057] Example 2 This embodiment provides a synchronous estimation device for multi-parameter deviations in new energy power plants, including: a determination module, a construction module, and a solution module.

[0058] The determination module is used to determine all steady-state moments of the new energy power plant during the current operating period. and their corresponding gears .

[0059] The construction module is used to construct the steady-state moments of the current runtime segment. Corresponding joint optimization objective function ; This represents the vector of parameters to be estimated involved in the joint optimization solution, among which the key estimated deviation parameters include: the measurement errors of each current transformer and the tap ratio deviations of each tap position of the on-load tap changer of the main transformer; the joint optimization objective function... This includes the sum of a first objective function, a second objective function, and a third objective function. The first objective function includes: at each steady-state time... Corresponding high-voltage side node current balance residual The average current of all branches on the high-voltage side, excluding the main branch, after error correction. The sum of ratios; the second objective function includes: the sum of ratios at each steady-state time. Corresponding low-voltage side node current balance residual The average current of all branches on the low-voltage side, excluding the main branch, after error correction. The sum of ratios; the third objective function includes: the sum of ratios at each steady-state time. and their corresponding gears Corresponding residuals of high and low voltage side currents of the main transformer The current after error correction of the low-voltage branch of the main transformer The sum of the ratios; The solver module is used to optimize the joint objective function. The objective is to minimize the vector of parameters to be estimated. The synchronous estimation results.

[0060] Example 3 This embodiment provides a synchronous estimation system for multi-parameter deviations within a new energy power plant, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps of the synchronous estimation method for multi-parameter deviations within a new energy power plant.

[0061] The electronic device can be a desktop computer, laptop, handheld computer, or cloud server, etc. The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The memory can be used to store computer programs and / or modules. The processor implements various functions of the electronic device by running or executing the computer programs and / or modules stored in the memory, and by accessing data stored in the memory.

[0062] Example 4 This embodiment provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the synchronous estimation method for multi-parameter deviations within the new energy power plant.

[0063] Specifically, the memory may include high-speed random access memory, as well as non-volatile memory, such as hard disks, RAM, plug-in hard disks, smart media cards (SMC), secure digital (SD) cards, flash cards, at least one disk storage device, flash memory device, or other volatile solid-state storage devices.

[0064] Example 5 This application provides a computer program product or computer program that includes computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform the steps of the method described in the above embodiments of this application.

[0065] The technical features of the embodiments described above can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. It should be noted that the terms "in one embodiment," "for example," and "as in another example" in this application are intended to illustrate the application and are not intended to limit the application.

[0066] The embodiments described above are merely examples of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application.

Claims

1. A method for synchronous estimation of multi-parameter deviations within a new energy power plant, characterized in that, include: S1: Determine all steady-state moments of the new energy power plant during its current operating period. and their corresponding gears ; S2: Construct the steady-state moments of the current runtime segment. Corresponding joint optimization objective function ; The vector of parameters to be estimated involved in the joint optimization solution includes: the measurement errors of each current transformer and the tap ratio deviations of each tap position of the on-load tap changer of the main transformer; the joint optimization objective function. Includes: the sum of the first objective function, the second objective function, and the third objective function; The first objective function includes: each steady-state time. Corresponding high-voltage side node current balance residual The average current of all branches on the high-voltage side, excluding the main branch, after error correction. The sum of ratios; the second objective function includes: the sum of ratios at each steady-state time. Corresponding low-voltage side node current balance residual The average current of all branches on the low-voltage side, excluding the main branch, after error correction. The sum of ratios; the third objective function includes: the sum of ratios at each steady-state time. and their corresponding gears Corresponding residuals of high and low voltage side currents of the main transformer The current after error correction of the low-voltage branch of the main transformer The sum of the ratios; S3: Using the joint optimization objective function The objective is to minimize the vector of parameters to be estimated. The synchronous estimation results.

2. The method for synchronous estimation of multi-parameter deviations within a new energy power plant as described in claim 1, characterized in that, The joint optimization objective function Represented as: ； in, , These represent the total number of current transformers in each branch of the high-voltage and low-voltage sides, excluding the main branch. , These are the currents of each branch on the high and low voltage sides, excluding the main branch, after error correction.

3. The synchronous estimation method for multi-parameter deviations within a new energy power plant as described in claim 2, characterized in that, ； ； ； in, Represents the steady-state moment The current in the low-voltage branch of the main transformer after error correction. Represents the steady-state moment The current in the high-voltage branch of the main transformer after error correction. steady state time The voltage estimate after error correction for the low-voltage side bus voltage transformer. The excitation impedance of the main transformer's excitation branch. Represents the steady-state moment Corresponding gear The following is the estimated actual tapping ratio: ； Represents the steady-state moment Corresponding gear The rated tap ratio, Represents the steady-state moment Corresponding gear The tap ratio deviation.

4. The synchronous estimation method for multi-parameter deviations within a new energy power plant as described in claim 2, characterized in that, The parameter vector to be estimated Represented as: ； in, This represents the ratio difference of each of the N current transformers. This represents the phase difference between N current transformers. Indicates the actual occurrence within the current runtime segment The tap ratio deviation of each gear; These represent the ratio difference and phase difference of the voltage transformer on the low-voltage side bus, respectively. These represent the real and imaginary parts of the excitation impedance corresponding to the excitation branch of the main transformer, respectively.

5. The synchronous estimation method for multi-parameter deviations within a new energy power plant as described in claim 1, characterized in that, S1 includes: S11: Collect the original operating dataset of the new energy plant during the current operating period; including: current measurement data of each branch on the high-voltage side of the main transformer, current measurement data of each branch on the low-voltage side of the main transformer, bus voltage measurement data, total number of tap ratio positions and tap range information of the main transformer. S12: Perform steady-state condition filtering on the original runtime dataset to obtain multiple steady-state moments. ; S13: For all steady-state moments The gear position recognition features are clustered or partitioned into intervals, and each steady-state moment is determined according to the partitioning results. corresponding gear .

6. The synchronous estimation method for multi-parameter deviations within a new energy power plant as described in claim 5, characterized in that, The original running dataset in S11 Represented as: ； in, The measured value of the low-voltage branch current of the main transformer. The measured value of the high-voltage branch current of the main transformer. For the low-voltage side, excluding the main transformer branch, the The current measurements of each branch are total. One measurement branch; For the high-voltage side, excluding the main transformer branch, the... The current measurements of each branch are total. One measurement branch; This is the measured value of the low-voltage side bus voltage; This is the measured value of the high-voltage side bus voltage.

7. The synchronous estimation method for multi-parameter deviations within a new energy power plant as described in claim 5, characterized in that, S12 includes: performing outlier removal on the original running dataset to obtain the dataset to be analyzed; if at a certain moment... The dataset to be analyzed satisfies: and , Then determine the time Corresponding to steady-state operating conditions and time steady state time ; For the entire current measurement sequence at time... The maximum normalized rate of change The high and low voltage side bus voltage measurement sequence at time 1 The maximum normalized rate of change The current steady-state criterion threshold, Voltage steady-state criterion threshold: ； ； For any measurement sequence Its maximum normalized rate of change is: ， A positive number is set to prevent the denominator from being zero. It is the time before time t.

8. The synchronous estimation method for multi-parameter deviations within a new energy power plant as described in claim 5, characterized in that, S13 includes: for all steady-state moments Corresponding gear recognition feature quantity The characteristic sequence constituted Perform cluster analysis or interval partitioning to identify the actual tap positions that occur within the current runtime. Establish each steady-state moment. With corresponding tap position The mapping relationship between them ; ； ； ； K represents all tap positions. The total number, steady state time Low-voltage side current polymerization amount, steady state time The corresponding high-voltage side current aggregation amount.

9. A synchronous estimation system for multi-parameter deviations in a new energy power plant, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the synchronous estimation method for multi-parameter deviations within new energy power plants as described in any one of claims 1 to 8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the synchronous estimation method for multi-parameter deviations within new energy power plants as described in any one of claims 1 to 8.

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