Active power measurement method and system for generator control system, medium and equipment

Abstract

The invention discloses an active power measurement method and system for a generator control system, a medium and equipment, and belongs to the technical field of electric power engineering.The method comprises the steps that a power output value is calculated through a power measurement instrument according to collected three-phase voltage and current waveform data; monitoring the harmonic content and the negative sequence voltage in the three-phase current, and judging the CT saturation condition of the current transformer: if the CT is saturated, correcting the distorted waveform based on the trained LSTM waveform correction model, and outputting a power correction value according to the corrected waveform; and if the current transformer CT is not saturated, outputting a power output value. According to the invention, the problem of power error adjustment caused by serious distortion of a power measurement signal due to saturation of a measurement-level CT iron core of the generator is solved.

Description

Technical Field

[0001] The present invention relates to a method, system, medium and device for measuring active power in a generator control system, belonging to the technical field of power engineering. Background Art

[0002] In the wave of the rapid global economic development, the sharp growth of power demand has promoted the intelligent, large-scale and efficient transformation of modern power systems. The continuous expansion of the power grid scale and the complexity of the structure have made it a key issue to be solved urgently to ensure the safe, stable and efficient operation of the power system. In this context, the power measuring instrument, as an indispensable measuring and converting device in the power system, plays a crucial role. It can accurately convert various power system power signals such as active power and reactive power into standard signals and is widely used in various links of power system generation, transmission and distribution. In the power generation link, the power measuring instrument helps to refine the management of new energy power generation, helps power generation enterprises optimize strategies, and ensures that the equipment maintains the best power generation efficiency; in the power transmission link, it monitors the line power in real time, provides data support for the dispatching department, and optimizes the power resource allocation; in the power distribution link, the power measuring instrument plays a key role in aspects such as electric energy metering, load management and fault diagnosis, improving the power supply reliability and power quality of the distribution network. The wide application of the power measuring instrument provides a strong technical guarantee for the safe and stable operation of the power system.

[0003] Although the power measuring instrument plays a crucial role in all aspects of the power system, its existing drawbacks cannot be ignored. The power measuring instrument in the prior art has weak ability to process transient characteristics. When the transient characteristics are obvious during the operation of the power system, such as the increase in current caused by an out-of-zone fault and the large amount of decaying DC components contained in the inrush current, etc., it may cause the current transformer CT to saturate. When the current transformer CT saturates, the current signal received by the power measuring instrument will be distorted, and this distorted current signal will directly affect the calculation result of the power measuring instrument, resulting in an abnormal power output value, which may further cause the problem of power misregulation. This will not only affect the stable operation of the power system, but also may cause damage to power equipment and users. Therefore, how to improve the ability of the power measuring instrument to process transient characteristics and reduce the influence of current transformer CT saturation on power measurement is a technical problem to be solved urgently at present. Summary of the Invention

[0004] The purpose of the present invention is to provide a method, system, medium and device for measuring active power in a generator control system, so as to solve the problem of power misregulation caused by serious distortion of the power measurement signal due to the saturation of the CT iron core of the generator measurement stage by avoiding the distortion of the output of the power measuring instrument caused by transient components.

[0005] To solve the above technical problems, the present invention is implemented by the following technical solutions:

[0006] In a first aspect, the present invention provides an active power measurement method for a generator control system, including:

[0007] Calculating a power output value through a power meter according to the collected three-phase voltage and current waveform data;

[0008] Monitoring the harmonic content in the three-phase current and the negative sequence voltage to judge the saturation condition of the current transformer CT:

[0009] If the current transformer CT is saturated, correcting the distorted waveform based on the trained LSTM waveform correction model, and outputting a power correction value according to the corrected waveform;

[0010] If the current transformer CT is not saturated, outputting the power output value.

[0011] Further, the saturation of the current transformer CT means that the increase value of the harmonic content / negative sequence voltage in any one of the three-phase currents exceeds a preset first threshold within a preset time.

[0012] Further, the non-saturation of the current transformer CT means that the increase values of the harmonic content and the negative sequence voltage in any one of the three-phase currents do not exceed a preset first increase value within a preset time.

[0013] Further, the value range of the first increase value is 5%-10% of the power output value.

[0014] Further, it also includes that after the power correction value is output, if the difference between the power correction value and the power output value is greater than a preset second threshold, outputting the power correction value to adjust the power of the generator control system; if the difference between the power correction value and the power output value is less than or equal to the preset second threshold, adjusting the power of the generator control system according to the power output value.

[0015] Further, a multi-head self-attention mechanism is introduced into the LSTM network to construct the LSTM waveform correction model.

[0016] Further, the training method of the LSTM waveform correction model includes:

[0017] Converting the three-phase voltage and current data obtained from experimental simulation and on-site waveform recording through a transformer into waveform data;

[0018] Using the waveform data as a training set to train and learn the LSTM waveform correction model;

[0019] Through multiple iterations of training, continuously adjust the parameters of the LSTM waveform correction model to obtain a trained LSTM waveform correction model.

[0020] In a second aspect, the present invention provides a computer system for implementing the active power measurement method for a generator control system as described in the first aspect.

[0021] In a third aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, which when executed by a processor, implements the active power measurement method for a generator control system as described in the first aspect.

[0022] In a fourth aspect, the present invention provides a computer device, comprising:

[0023] A memory for storing instructions;

[0024] A processor for executing the instructions such that the device performs operations to implement the active power measurement method for a generator control system as described in the first aspect.

[0025] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0026] 1. The present invention determines the saturation state of the current transformer CT by real-time monitoring of the harmonic content in the three-phase current and the negative sequence voltage, and when the CT is saturated, uses a pre-trained LSTM waveform correction model to correct the distorted waveform and output a power correction value, significantly improving the accuracy and stability of active power measurement. Especially in complex working conditions where the transient characteristics of the power system are obvious and the CT is prone to saturation, it can effectively avoid power measurement errors caused by CT saturation. The present invention solves the problem of power misregulation caused by serious distortion of the power measurement signal due to saturation of the core of the measuring-level CT of the generator, provides reliable data support for the precise regulation of the generator control system, and further enhances the safe and stable operation ability of the power system.

[0027] 2. The present invention monitors the harmonic content in the three-phase current and the negative sequence voltage, and determines whether the increment exceeds a preset first threshold within a preset time, thereby accurately identifying the saturation state of the current transformer CT, enabling the system to make a rapid response at the initial stage of CT saturation, effectively avoiding the accumulation of power measurement errors caused by CT saturation, and improving the real-time performance and accuracy of active power measurement.

[0028] 3. The LSTM waveform correction model provided by the present invention is constructed by combining the LSTM network with the multi-head self-attention mechanism, which can capture waveform features more precisely, achieve high-precision waveform recovery, and the power correction value calculated based on the corrected waveform also significantly improves the accuracy of active power measurement, providing a more reliable data basis for the power regulation of the generator control system and helping to optimize the operation efficiency of the power system.

[0029] 4. After the output power correction value is obtained, the present invention further adjusts the power of the generator control system intelligently according to the comparison result between the difference between the power correction value and the original power output value and a preset second threshold, enabling the system to make flexible adjustments according to the real-time power measurement situation, effectively coping with power fluctuations in the power system, and enhancing the stability and robustness of the generator control system. At the same time, through experimental simulation and the training of on-site recorded wave data, the accuracy and applicability of the LSTM waveform correction model are ensured, further improving the safe and stable operation ability of the entire power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic flowchart of an active power measurement method for a generator control system provided by an embodiment of the present invention;

[0031] Figure 2 is a schematic diagram of a simulation structure provided by an embodiment of the present invention;

[0032] Figure 3 is an example diagram of power image data before correcting a distorted waveform provided by an embodiment of the present invention;

[0033] Figure 4 is an example diagram of waveform image data after correcting a distorted waveform provided by an embodiment of the present invention;

[0034] Figure 5 is a schematic diagram of the change of the loss value during the training process of the LSTM network provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The technical solutions of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific features in the embodiments of the present invention and the embodiments are detailed descriptions of the technical solutions of the present invention, rather than limitations on the technical solutions of the present invention. Without conflict, the technical features in the embodiments of the present invention and the embodiments can be combined with each other.

[0036] The term "and / or" is merely a description of the association relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. Additionally, the character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0037] Embodiment 1

[0038] As Figure 1 shown, this embodiment introduces an active power measurement method for a generator control system, including:

[0039] Step 1: Collect three-phase voltage and current waveform data.

[0040] The three-phase voltage and current waveform data collected in this embodiment are the three-phase voltage of the generator and the current of the three-phase measuring-level CT.

[0041] Step 2: Calculate the power output value through a power meter according to the collected three-phase voltage and current waveform data.

[0042] Step 3: Monitor the harmonic content in the three-phase current and the negative-sequence voltage to judge the saturation situation of the current transformer CT.

[0043] If the harmonic content in the current increases or the negative-sequence voltage suddenly surges, it indicates that the measured system may be in an abnormal state. This abnormality may stem from the real power fluctuation caused by a fault or the power fluctuation illusion caused by transient components. To prevent misregulation caused by power transfer distortion, it is necessary to verify whether the power fluctuation in the system is caused by the output power distortion due to the saturation of the current transformer CT or directly by the power fluctuation caused by a fault. Among them, if there is output power distortion caused by CT saturation, the distorted waveform will be corrected using a neural network model to obtain an accurate power output again. If there is no output power distortion caused by CT saturation, it indicates that the waveform is not affected by CT saturation, and the power fluctuation at this time is the real power fluctuation caused by the fault. In this case, the power measurement result should be directly used as the reference basis for power regulation.

[0044] In this embodiment, if the current transformer CT is saturated, the distorted waveform is corrected based on the trained LSTM waveform correction model, and the power correction value is output according to the corrected waveform;

[0045] If the current transformer CT is not saturated, the power output value is output.

[0046] If the second harmonic content of a certain phase current in the three-phase current suddenly increases, the current waveform of this phase shows non-sinusoidal characteristics, and the distortion of the current indicates that there is an abnormality in the system operation, and the power will also fluctuate at this time.

[0047] In this embodiment, the saturation of the current transformer CT means that the increase value of the harmonic content / negative sequence voltage in any one of the three-phase currents exceeds a preset first threshold within a preset time.

[0048] If the negative sequence voltage of a certain phase in the three-phase voltage suddenly increases, it indicates that the system is in an unbalanced state. A large number of negative sequence components will also cause other problems, and at this time, the power will also fluctuate.

[0049] In this embodiment, the unsaturation of the current transformer CT means that the increase values of the harmonic content and negative sequence voltage in any one of the three-phase currents do not exceed a preset first increase value within a preset time. In this embodiment, the value range of the first increase value is 5%-10% of the power output value.

[0050] If the current harmonic content suddenly increases or the negative sequence voltage increases, a short-circuit fault or system disturbance may have occurred, and there is a risk of saturation of the current transformer CT. Otherwise, there is no risk of saturation of the current transformer CT, and the power output value can be directly measured by a power meter.

[0051] In some embodiments, a multi-head self-attention mechanism is introduced into the LSTM network to construct the LSTM waveform correction model. The LSTM network includes an input gate, a forget gate, and an output gate.

[0052] Among them, the input gate includes a Sigmoid layer and a tanh layer. The Sigmoid layer outputs a vector between 0 and 1, which is used to indicate the update degree of each element in the memory cell, where 0 means no update and 1 means complete update. The tanh layer generates a new candidate value vector, and the candidate value vector is multiplied by the output of the input gate to jointly determine which new information will be added to the memory cell.

[0053] Among them, the forget gate is a Sigmoid layer, and the forget gate outputs a vector between 0 and 1, which is used for the previous state of the memory cell. When the output value of the forget gate is 0, it means that the corresponding information in the memory cell at the previous moment is completely discarded; when the output value of the forget gate is 1, it means that it is completely retained. Through the forget gate, the LSTM network can decide whether to retain the long-term information in the memory cell according to the current input.

[0054] Among them, the output gate determines the output content of the memory cell in two steps. First, the Sigmoid layer determines which parts of the memory cell will be output according to the current input and the previous hidden state. Then, the tanh layer transforms the memory cell, maps the value to between -1 and 1, and multiplies it by the output of the Sigmoid layer to finally obtain the output of the LSTM network.

[0055] In this implementation, MATLAB / Simulink is used to perform batch simulations on the system, and the simulation structure is as shown in Figure 2 . By setting the system impedance, residual magnetism, and closing angle, the voltage and current under different operating conditions are simulated, and the three-phase voltage and current data obtained from the experimental simulation and on-site recording are obtained.

[0056] In this embodiment, the training method of the LSTM waveform correction model includes:

[0057] The three-phase voltage and current data obtained from the experimental simulation and on-site recording are converted into waveform data through a transformer;

[0058] Taking the waveform data as a training set, the LSTM waveform correction model is trained and learned;

[0059] Through multiple iterative trainings, the parameters of the LSTM waveform correction model are continuously adjusted to obtain a trained LSTM waveform correction model.

[0060] Among them, the change of the loss value during the training process is as shown in Figure 5 . As the number of iterations increases, the loss value gradually decreases and finally approaches 0.

[0061] In this embodiment, by verifying the trained LSTM waveform correction model, an example diagram of the waveform image data before and after correcting the distorted waveform is obtained, as shown in Figure 3 , Figure 4 . Among them, Figure 3 , Figure 4 The dotted line in is the current signal actually output by the power meter, the solid line is the power signal during actual operation, and the dash-dotted line is the power signal obtained after correction. The power after correction can more correctly reflect the system operation condition.

[0062] Step 4: Adjust the power of the generator control system.

[0063] In some embodiments, after the power correction value is output, it further includes:

[0064] If the difference between the power correction value and the power output value is large, the power fluctuation is an illusion caused by the transient component. Output the power correction value and promptly switch to another set of current transformers CT; if the difference between the power correction value and the power output value is small, the power fluctuation is a real power fluctuation caused by a fault, and directly output the power output value.

[0065] In this embodiment, if the difference between the power correction value and the power output value is greater than a preset second threshold, the power correction value is output and the power of the generator control system is adjusted; if the difference between the power correction value and the power output value is less than or equal to the preset second threshold, the power of the generator control system is adjusted according to the power output value.

[0066] Embodiment 2

[0067] Based on the same inventive concept as Embodiment 1, this embodiment introduces a computer system, which is characterized in that it is used to implement the active power measurement method for the generator control system as described in Embodiment 1 or 2.

[0068] Embodiment 3

[0069] Based on the same inventive concept as other embodiments, this embodiment introduces a computer-readable storage medium, on which a computer program is stored, and is characterized in that when the computer program is executed by a processor, it implements the active power measurement method for the generator control system as described in Embodiment 1 or 2.

[0070] Embodiment 4

[0071] Based on the same inventive concept as other embodiments, this embodiment introduces a computer device, including:

[0072] A memory for storing instructions;

[0073] A processor for executing the instructions, so that the device performs the operation of implementing the active power measurement method for the generator control system as described in Embodiment 1 or 2

[0074] In summary of the above embodiments, the present invention determines the saturation state of the current transformer CT by real-time monitoring of the harmonic content in the three-phase current and the negative sequence voltage, and uses the pre-trained LSTM waveform correction model to correct the distorted waveform when CT is saturated, and outputs the power correction value, significantly improving the accuracy and stability of active power measurement. Especially in complex working conditions where the transient characteristics of the power system are obvious and CT is prone to saturation, it can effectively avoid power measurement errors caused by CT saturation, provide reliable data support for the precise regulation of the generator control system, and further enhance the safe and stable operation ability of the power system.

[0075] The present invention monitors the harmonic content in the three-phase current and the negative sequence voltage, and judges whether its increment exceeds a preset first threshold within a preset time, so as to accurately identify the saturation state of the current transformer CT, enabling the system to make a rapid response at the initial stage when CT saturation occurs, effectively avoiding the accumulation of power measurement errors caused by CT saturation, and improving the real-time performance and accuracy of active power measurement.

[0076] The LSTM waveform correction model provided by the present invention is constructed by combining the LSTM network with the multi-head self-attention mechanism, which can capture waveform features more precisely, achieve high-precision waveform recovery. The power correction value calculated based on the corrected waveform also significantly improves the accuracy of active power measurement, provides a more reliable data basis for the power regulation of the generator control system, and helps to optimize the operation efficiency of the power system.

[0077] After the present invention outputs the power correction value, it further intelligently adjusts the power of the generator control system according to the comparison result between the difference between the power correction value and the original power output value and a preset second threshold, so that the system can make flexible adjustments according to the real-time power measurement situation, effectively cope with the power fluctuations in the power system, and enhance the stability and robustness of the generator control system. At the same time, through experimental simulation and the training of on-site recorded wave data, the accuracy and applicability of the LSTM waveform correction model are ensured, further improving the safe and stable operation ability of the entire power system.

[0078] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. 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. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memory, CD-ROM, optical memory, etc.) containing computer-usable program code.

[0079] The present invention is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram can be implemented by computer program instructions, and the combination of the processes and / or blocks in the flowchart and / or block diagram can also be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for realizing the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0080] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device, and the instruction device realizes the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0081] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus, so that a series of operation steps are executed on the computer or other programmable apparatus to produce a computer-implemented process, thereby the instructions executed on the computer or other programmable apparatus provide steps for realizing the functions specified in one process Figure 1 one process or a plurality of processes and / or blocks Figure 1 or a plurality of blocks.

[0082] The embodiments of the present invention have been described above in conjunction with the accompanying drawings. However, the present invention is not limited to the above specific embodiments. The above specific embodiments are merely illustrative rather than restrictive. Under the inspiration of the present invention, those of ordinary skill in the art can also make many forms without departing from the spirit of the present invention and the scope protected by the claims. All of these fall within the protection scope of the present invention.

Claims

1. A method for measuring active power in a generator control system, characterized in that: include: According to the collected three-phase voltage and current waveform data, the power output value is calculated by a power measuring instrument; Monitor the harmonic content and negative sequence voltage in the three-phase current to determine the saturation of the current transformer CT: If the current transformer CT is saturated, the distorted waveform is corrected based on the trained LSTM waveform correction model, and the power correction value is output according to the corrected waveform; If the current transformer CT is not saturated, the power output value is output.

2. The active power measurement method for a generator control system according to claim 1, characterized in that: The saturation of the current transformer CT indicates that the increase in harmonic content / negative sequence voltage in any phase current of the three-phase current exceeds a preset first threshold within a preset time.

3. The active power measurement method for a generator control system according to claim 1, characterized in that: The non-saturation of the current transformer CT indicates that the increase in harmonic content and negative sequence voltage in any phase current of the three-phase current within a preset time does not exceed a preset first increase in value.

4. The active power measurement method for a generator control system according to claim 1, characterized in that: The value range of the first added value is 5%-10% of the power output value.

5. The active power measurement method for a generator control system according to claim 1, characterized in that: It also includes, after outputting the power correction value, if the difference between the power correction value and the power output value is greater than a preset second threshold value, then outputting the power correction value to adjust the power of the generator control system; if the difference between the power correction value and the power output value is less than or equal to the preset second threshold value, then adjusting the power of the generator control system according to the power output value.

6. The active power measurement method for a generator control system according to claim 1, characterized in that: A multi-head self-attention mechanism is introduced into the LSTM network to construct the LSTM waveform correction model.

7. The active power measurement method for a generator control system according to claim 6, characterized in that: The training method of the LSTM waveform correction model includes: The three-phase voltage and current data obtained from experimental simulation and on-site recording are converted into waveform data through mutual inductors; Using the waveform data as a training set, training and learning the LSTM waveform correction model; Through multiple iterative trainings, the parameters of the LSTM waveform correction model are continuously adjusted to obtain a trained LSTM waveform correction model.

8. A computer system, characterized in that: Used to implement the active power measurement method for a generator control system as described in any one of claims 1-7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the active power measurement method for a generator control system as described in any one of claims 1 to 7 is implemented.

10. A computer device, characterized in that: include: A memory for storing instructions; A processor is used to execute the instructions so that the device performs operations to implement the active power measurement method for a generator control system as described in any one of claims 1-7.

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