High and low voltage electric energy quality analysis and treatment method and system

Abstract

The invention discloses a high-low voltage electric energy quality analysis and treatment method and system, and the method comprises the following steps: collecting electric energy quality data of a high-voltage side and a low-voltage side, the high-voltage side being in a 110kV or 220kV voltage level, and the low-voltage side being in a 35kV or 0.4 kV voltage level; according to the collected data, the harmonic coupling relation between the high-voltage side and the low-voltage side is analyzed, and a system resonance frequency point is identified; based on the analysis result, generating a multi-objective optimization treatment strategy; according to the treatment strategy, the high-voltage side active power filter and the low-voltage side passive power filter are controlled to operate cooperatively with the static var generator; and verifying the treatment effect and feeding back and correcting the treatment parameters. Through cooperative control and cooperative use of the high-voltage side harmonic detection device and the low-voltage side treatment equipment, dynamic blocking of a high-voltage and low-voltage power grid harmonic coupling path is realized, the problems of repeated transmission of high-voltage and low-voltage harmonics and unstable treatment effect in the prior art are solved, and the overall harmonic distortion rate of the system is remarkably reduced.

Description

Technical Field

[0001] This invention relates to the field of power system power quality management, specifically to a method and system for analyzing and managing high and low voltage power quality. Background Technology

[0002] With the large-scale grid connection of new energy sources such as wind power and photovoltaics, power quality issues in power systems are becoming increasingly prominent. New energy power generation equipment (such as inverters and converters) generates broadband harmonics (2kHz–5kHz) during operation, and due to their output fluctuations, they are prone to voltage flicker and three-phase imbalance. In traditional power grids, power quality issues on the high-voltage side (110kV / 220kV) and the low-voltage side (10kV / 0.4kV) are usually addressed independently. However, actual operation shows that high- and low-voltage grids form harmonic transmission channels through transformer coupling. For example, the 11th harmonic from a low-voltage photovoltaic power station may be amplified by the transformer, affecting the voltage distortion rate of the high-voltage bus. International standards (such as IEEE 519-2022) impose stricter requirements on harmonic limits at grid connection points, necessitating a comprehensive management solution covering all voltage levels.

[0003] Existing pollution control solutions primarily target individual voltage levels and fail to effectively address harmonic coupling between high- and low-voltage power grids. In practice, while high-voltage side pollution control equipment can suppress harmonics at its own voltage level, the lack of a coordinated control mechanism with low-voltage side equipment means that the controlled harmonics can still be reintroduced to the other side via coupling paths such as transformers, resulting in repeated pollution. The limitations of this approach are manifested in the unstable overall system effectiveness and the underutilization of the equipment's operational efficiency. Summary of the Invention

[0004] The purpose of this invention is to provide a method and system for analyzing and managing high and low voltage power quality, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for analyzing and managing high and low voltage power quality includes the following steps:

[0007] Step S1: Collect power quality data on the high-voltage side and the low-voltage side, wherein the high-voltage side is at a voltage level of 110kV or 220kV, and the low-voltage side is at a voltage level of 35kV or 0.4kV.

[0008] Step S2: Based on the collected data, analyze the harmonic coupling relationship between the high-voltage side and the low-voltage side, and identify the system resonant frequency.

[0009] Step S3: Based on the analysis results, generate a multi-objective optimization governance strategy;

[0010] Step S4: According to the governance strategy, control the coordinated operation of the high-voltage side active power filter and the low-voltage side passive filter with the static var generator;

[0011] Step S5: Verify the treatment effect and provide feedback to correct the treatment parameters.

[0012] Preferably, step S1 includes acquiring voltage and current waveforms on the high-voltage side using a synchronous phasor measurement device conforming to the IEC 61850-9-2 standard, and acquiring harmonic characteristic data at the outlet of the low-voltage side new energy power generation equipment using an edge computing node.

[0013] Preferably, step S2 includes establishing harmonic transfer function models for the high-voltage side and the low-voltage side, and triggering a graded alarm mechanism when the total harmonic voltage distortion rate exceeds a preset threshold.

[0014] Preferably, in step S3, the multi-objective optimization includes the objective of minimizing harmonic distortion rate, the objective of optimizing reactive power compensation economy, and the objective of maximizing voltage stability.

[0015] Preferably, in step S4, the response time of the high-voltage side active power filter is no more than 1 millisecond, and the response time of the low-voltage side passive filter and static var generator is no more than 10 milliseconds, so that the coordinated control of high and low voltage equipment is realized through the 5G communication network.

[0016] A smart collaborative management system for high and low voltage power quality, including

[0017] The data acquisition module is used to collect power quality data on the high-voltage and low-voltage sides.

[0018] The resonance analysis module is used to analyze harmonic coupling relationships and identify resonant frequencies.

[0019] The strategy generation module is used to generate multi-objective optimization governance strategies;

[0020] The equipment control module is used to control the operation of the active power filter, passive filter, and static var generator;

[0021] The effect verification module is used to verify the treatment effect and provide feedback for corrective parameters.

[0022] Preferably, the data acquisition module includes a high-voltage side synchronous phasor measurement device and a low-voltage side edge computing terminal.

[0023] Preferably, it also includes

[0024] A digital twin platform is used to build system simulation models and calibrate parameters in real time.

[0025] Economic evaluation unit, used to calculate governance cost and benefit indicators.

[0026] A computer-readable storage medium having a computer program stored thereon that, when executed by a processor, implements the steps of the method.

[0027] An electronic device includes a memory and a processor, the memory storing a computer program, the processor executing the program to implement the steps of the method.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] 1. This invention achieves dynamic blocking of harmonic coupling paths between high-voltage and low-voltage power grids by using a high-voltage side harmonic detection device and a low-voltage side treatment device in a coordinated control manner. This solves the problems of repeated transmission of high and low voltage harmonics and unstable treatment effects in the prior art, and significantly reduces the overall harmonic distortion rate of the system.

[0030] 2. This invention improves the accuracy and response speed of harmonic mitigation by combining multi-timescale data fusion analysis with a hybrid filter dynamic optimization strategy, solves the problem of insufficient efficiency of traditional single mitigation equipment, and significantly improves the overall efficiency of power quality management. Attached Figure Description

[0031] Figure 1 This is a diagram of the cloud-edge-device three-level architecture of the present invention;

[0032] Figure 2 This is a flowchart illustrating the dynamic collaborative governance process of the present invention.

[0033] Figure 3 This is a timing diagram for the implementation of the industrial park power grid according to the present invention. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1

[0036] This invention addresses the problem of aggravated grid harmonic pollution caused by the large-scale integration of new energy sources, and the mutual coupling and amplification of harmonics between high and low voltage sides. It achieves comprehensive power quality optimization and management through multi-timescale data fusion analysis and dynamic collaborative control of hybrid filters. Since it involves power electronic equipment control and grid dynamic modeling, the following technical objectives need to be achieved based on the hardware architecture:

[0037] Accurate detection of high-voltage side harmonics (sampling frequency ≥10kHz, measurement error ≤0.5%);

[0038] High and low voltage governance equipment coordinated response (control command transmission delay ≤ 2ms);

[0039] Dynamic optimization of governance strategy (calculation cycle ≤ 1 second, objective function convergence error ≤ 3%).

[0040] Based on the above technical requirements, this embodiment adopts the following... Figure 1 The cloud-edge-device three-tier collaborative governance architecture is shown below:

[0041] High-voltage monitoring layer:

[0042] It consists of a synchronous phasor measurement unit (PMU) installed on the 110kV / 220kV bus, which communicates with the master station via fiber optic Ethernet and transmits sampled value messages using the IEC 61850-9-2 protocol, transmitting 256 points of waveform data per cycle.

[0043] The hardware core is a Xilinx Zynq UltraScale+ MPSoC, with a built-in harmonic extraction algorithm for real-time calculation. Among them, V h This is the effective value of the h-th harmonic voltage.

[0044] Edge computing layer:

[0045] An industrial server (such as Advantech ARK-3530) deployed in a substation runs the resonance analysis module to establish a harmonic impedance matrix model:

[0046]

[0047] Among them, Z 12 (f) represents the mutual impedance between the high and low voltage sides at frequency f.

[0048] When |Z is detected 12 (f)| / |Z 11 When (f)|>5, it is determined that there is a risk of harmonic coupling.

[0049] Equipment control layer:

[0050] The high-voltage APF uses a three-level H-bridge topology with a switching frequency of 20kHz. Achieve current tracking control;

[0051] The low-voltage SVG and PPF are connected via hardwiring, and the switching logic satisfies Q. SVG +Q PPF =Q load -ΔQ th , where ΔQ thThis represents the threshold margin.

[0052] like Figure 2 As shown, the specific process of the dynamic collaborative governance method executed on this architecture includes:

[0053] Step 1, Data Acquisition and Synchronization: Collect power quality data from the high-voltage side and the low-voltage side. The high-voltage side is at a voltage level of 110kV or 220kV, and the low-voltage side is at a voltage level of 35kV or 0.4kV.

[0054] The high-voltage PMU captures the voltage signal at a sampling rate of 10kHz. Achieve μs-level time alignment using the PTPv2 protocol;

[0055] Low-voltage side acquisition of inverter output current i inv (t), and the envelope features are extracted by Hilbert transform.

[0056] Step 2, resonant mode analysis: Based on the collected data, analyze the harmonic coupling relationship between the high-voltage side and the low-voltage side, and identify the system resonant frequency.

[0057] Solve the system characteristic equation det(Y) sys (f)+Y filter (f))=0, thus obtaining the resonant frequency point f. r ;

[0058] In one specific embodiment, the calculation results for a wind farm show that at the 25th harmonic (1250Hz), |Z 22 (f r )|=185Ω, far exceeding the normal value of 50Ω.

[0059] Step 3, Multi-objective optimization: Based on the analysis results, generate multi-objective optimization governance strategies.

[0060] Construct the objective function:

[0061]

[0062] Where x = [K] p ,K i Q PPF [] represents the decision variable, and VSM represents the voltage stability margin;

[0063] The NSGA-III algorithm was used to solve the Pareto front, and THD was ultimately chosen. v =3.8%

[0064] Step 4, Equipment Control and Verification: Based on the governance strategy, control the coordinated operation of the high-voltage side active power filter and the low-voltage side passive filter with the static var generator, verify the governance effect, and provide feedback to correct the governance parameters.

[0065] High-voltage APF injection compensation current i c (t)=-∑ h＝5,7,11 I h sin(2πhf0t+θ h );

[0066] Low-voltage SVG according to Q ref =P load tan(cos -1 PF target Dynamically adjust reactive power output.

[0067] Example 2

[0068] like Figure 3 As shown, suppose the power grid of an industrial park has the following problems:

[0069] Basic parameters:

[0070] High voltage side: 110kV busbar, background harmonics (5th order = 3.2%, 7th order = 2.1%);

[0071] Low-voltage side: Photovoltaic power plant (10MW inverter), generating 11th harmonic (4.8%).

[0072] The specific implementation process is as follows:

[0073] Coupling analysis:

[0074] Through Z sys (f) Calculations revealed that the 11th harmonic transmission coefficient reached 7.3 (normally less than 3), indicating a significant amplification effect;

[0075] Strategy generation:

[0076] The optimized control parameter is K. p =0.85, K i =1200, Q PPF = 1.2 Mvar;

[0077] Treatment effect:

[0078] Before treatment: THDv of 110kV busbar = 6.7%, THDv of 35kV busbar = 8.9%;

[0079] After treatment: the levels decreased to 2.3% and 3.1% respectively, and the measured dynamic response time of SVG was 9.2ms.

[0080] The process of estimating the resonant frequency is as follows:

[0081] System equivalent circuit admittance matrix:

[0082]

[0083] Filter admittance term:

[0084]

[0085] Let det(Y) sys +Y filter =0), solving for:

[0086]

[0087] Example 3

[0088] This embodiment provides a specific implementation of a smart collaborative governance system for high and low voltage power quality, including a digital twin platform and an economic evaluation unit, as detailed below:

[0089] The digital twin platform, based on the actual power grid topology, establishes simulation models of high- and low-voltage power grids, including equivalent circuit models of transformers, filters, and renewable energy grid connection points. By collecting real-time power grid operation data (such as voltage, current, and harmonic content), the least squares method is used to dynamically adjust the simulation model parameters, ensuring that the simulation accuracy error is ≤3%.

[0090] In one specific embodiment, before implementing the governance strategy, the harmonic suppression effect is simulated on the digital twin platform, the control parameters of SVG (Static Var Generator) and APF (Active Power Filter) are optimized, and then the data is sent to the actual equipment for execution.

[0091] The economic evaluation unit calculates the initial investment cost, operating energy consumption, and maintenance costs of the harmonic mitigation equipment, and calculates the total life cycle cost based on an annual depreciation rate of 10%. It also calculates the economic benefits resulting from reduced penalties and extended equipment lifespan based on power quality indicators (such as the percentage reduction in THDv) before and after harmonic mitigation. An economic analysis report, including the return on investment (ROI) and net present value (NPV), is generated for operational and maintenance decision-making.

[0092] Example 4

[0093] This embodiment provides a specific implementation method for a computer program product:

[0094] The following are computer-readable storage media:

[0095] The storage medium is an industrial-grade SSD with built-in power quality management and control program. The program execution flow includes:

[0096] Step 1: Real-time acquisition of power grid data (via IEC 61850 protocol);

[0097] Step 2: Call a harmonic detection algorithm (such as FFT transform) to calculate the harmonic content;

[0098] Step 3: Generate control commands and send them to the treatment equipment.

[0099] The electronic devices are as follows:

[0100] Hardware configuration:

[0101] Processor: Intel Xeon quad-core CPU, clock speed ≥ 2.4GHz;

[0102] Memory: 16GB DDR4, with ECC verification function;

[0103] Communication interface: Dual optical port redundancy design, supporting Modbus TCP and GOOSE communication.

[0104] Software environment:

[0105] Operating system: Linux RT real-time kernel;

[0106] Operation cycle: Control commands are updated every 100ms.

[0107] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0108] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for analyzing and managing high and low voltage power quality, characterized in that, Includes the following steps Step S1: Collect power quality data on the high-voltage side and the low-voltage side, wherein the high-voltage side is at a voltage level of 110kV or 220kV, and the low-voltage side is at a voltage level of 35kV or 0.4kV. Step S2: Based on the collected data, analyze the harmonic coupling relationship between the high-voltage side and the low-voltage side, and identify the system resonant frequency. Step S3: Based on the analysis results, generate a multi-objective optimization governance strategy; Step S4: According to the governance strategy, control the coordinated operation of the high-voltage side active power filter and the low-voltage side passive filter with the static var generator; Step S5: Verify the treatment effect and provide feedback to correct the treatment parameters.

2. The method for analyzing and managing high and low voltage power quality according to claim 1, characterized in that: Step S1 includes acquiring voltage and current waveforms on the high-voltage side using a synchronous phasor measurement device conforming to the IEC 61850-9-2 standard, and acquiring harmonic characteristic data at the outlet of the low-voltage side new energy power generation equipment using an edge computing node.

3. The method for analyzing and managing high and low voltage power quality according to claim 1, characterized in that: Step S2 includes establishing harmonic transfer function models for the high-voltage side and the low-voltage side, and triggering a graded alarm mechanism when the total harmonic voltage distortion rate exceeds a preset threshold.

4. The method for analyzing and managing high and low voltage power quality according to claim 1, characterized in that: In step S3, the multi-objective optimization includes the objectives of minimizing harmonic distortion rate, optimizing reactive power compensation economy, and maximizing voltage stability.

5. The method for analyzing and managing high and low voltage power quality according to claim 1, characterized in that: In step S4, the response time of the high-voltage side active power filter is no more than 1 millisecond, and the response time of the low-voltage side passive filter and static var generator is no more than 10 milliseconds. The coordinated control of high and low voltage equipment is achieved through the 5G communication network.

6. A smart collaborative management system for high and low voltage power quality, characterized in that, include The data acquisition module is used to collect power quality data on the high-voltage and low-voltage sides. The resonance analysis module is used to analyze harmonic coupling relationships and identify resonant frequencies. The strategy generation module is used to generate multi-objective optimization governance strategies; The equipment control module is used to control the operation of the active power filter, passive filter, and static var generator; The effect verification module is used to verify the treatment effect and provide feedback for corrective parameters.

7. The intelligent collaborative management system for high and low voltage power quality according to claim 6, characterized in that: The data acquisition module includes a high-voltage side synchronous phasor measurement device and a low-voltage side edge computing terminal.

8. The intelligent collaborative management system for high and low voltage power quality according to claim 6, characterized in that: Also includes A digital twin platform is used to build system simulation models and calibrate parameters in real time. Economic evaluation unit, used to calculate governance cost and benefit indicators.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the program implements the steps of the method according to any one of claims 1 to 5.

10. An electronic device comprising a memory and a processor, characterized in that, The memory stores a computer program, and when the processor executes the program, it implements the steps of the method according to any one of claims 1 to 5.

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