Electric power engineering quality assessment early warning system based on data analysis

Abstract

The invention relates to the field of electric power quality detection, and discloses an electric power engineering quality evaluation early warning system based on data analysis, which comprises a monitoring unit, a database, an electric power quality calculation unit, a quality membership analysis unit and a trend estimation unit, the monitoring unit comprises a voltage monitoring module, a frequency monitoring module, a three-phase voltage monitoring module and a power grid harmonic monitoring module, the voltage monitoring module is used for acquiring an actual voltage value, the frequency monitoring module is used for acquiring a power grid system frequency actual value, and the three-phase voltage monitoring module is used for acquiring voltage positive-sequence and negative-sequence component root-mean-square values; the power grid harmonic monitoring module is used for acquiring harmonic information of a power grid system, the monitoring unit is used for transmitting the information to the database, and the database stores the information and attaches keywords and timestamps; according to the method, the voltage deviation, the frequency deviation, the three-phase voltage unbalance degree, the voltage fluctuation and the voltage total harmonic distortion rate can be pre-estimated and calculated according to the previous parameters, so that the electric power quality evaluation and early warning function is realized.

Description

Technical Field

[0001] The present invention relates to the field of power quality detection, and in particular to a power engineering quality assessment and early warning system based on data analysis. Background Art

[0002] Since entering the new era, as people's attention to electricity consumption has gradually increased, the issue of power quality has also received more and more attention. Ensuring the quality of electricity consumption can reduce unnecessary energy loss on the one hand, and ensure the safety and reliability of power grid operation on the other hand. The power grid has a more prominent complexity in the actual operation process, which makes the analysis and evaluation of power quality also face corresponding difficulties. The issue of power quality is no longer just a single technical issue, but is more related to many aspects such as economic development. Power quality refers to the quality of electric energy in the power system. There are many factors that affect the quality of electric energy. The situations that cause power equipment failures or abnormal operation of the power supply system all belong to this category. Power quality assessment mainly includes voltage quality, current quality, power supply quality, power consumption quality and many other aspects. The main parameters are voltage, current, frequency, power, harmonics, flicker and so on.

[0003] At present, the assessment of power quality requires manual integration and analysis of data after sensors receive parameters. This is inefficient and requires multiple manual checks to prevent information errors. In addition, there is a lack of relevant early warning measures, and it is impossible to predict the trend of relevant power parameters based on historical information. Summary of the invention

[0004] The purpose of the present invention is to solve the problem that the current power engineering quality assessment requires manual integration and analysis of data after the sensors receive the parameters. During operation, the efficiency is low and multiple manual checks are required to prevent information errors. In addition, there is a lack of relevant early warning measures and it is impossible to predict the trend of relevant power parameters based on historical information.

[0005] The object of the present invention can be achieved by the following technical solutions: A power engineering quality assessment and early warning system based on data analysis, comprising a monitoring unit, a database, a power quality calculation unit, a quality membership analysis unit, and a trend prediction unit; The monitoring unit includes a voltage monitoring module, a frequency monitoring module, a three-phase voltage monitoring module, and a power grid harmonic monitoring module. The voltage monitoring module is used to obtain the actual voltage value, the frequency monitoring module is used to obtain the actual value of the power grid system frequency, the three voltage monitoring modules are used to obtain the root mean square values ​​of the positive and negative sequence components of the voltage, and the power grid harmonic monitoring module is used to obtain the harmonic information of the power grid system. The monitoring unit is used to transmit the information to a database, and the database saves the information and attaches keywords and timestamps. The power quality calculation unit is composed of a voltage quality module, a frequency quality module, three voltage quality modules, a power grid harmonic quality module, and a voltage fluctuation module. The power quality calculation unit is used to perform classified quality calculation processing according to keywords, and the classified quality calculation processing includes voltage deviation calculation, frequency deviation calculation, three-phase load imbalance calculation, voltage fluctuation calculation, and voltage total harmonic distortion rate calculation; The quality membership analysis unit is used to perform evaluation and integration processing based on the output information of the power quality calculation unit, and the trend prediction unit is used to perform budget processing based on historical information.

[0006] Further, the step of calculating the voltage deviation is: Get the actual voltage and the system nominal voltage; The voltage deviation is obtained based on the percentage of the difference between the actual voltage and the system nominal voltage and the ratio of the system nominal voltage. Its expression is: , where SU is the voltage deviation, Ua is the actual voltage, and Ub is the system nominal voltage.

[0007] The voltage deviation is obtained by calculation, which facilitates the evaluation of power quality.

[0008] Furthermore, the step of calculating the frequency deviation is: Get the actual frequency and the system nominal frequency The frequency deviation is obtained by the formula F=fa-fb, where F is the frequency deviation, fa is the actual frequency, and fb is the system nominal frequency.

[0009] The frequency deviation is obtained by calculation, which facilitates the evaluation of power quality.

[0010] Furthermore, the steps of calculating the three-phase load imbalance are: Get the RMS value of the positive and negative sequence components of voltage, and get the RMS value of the positive and negative sequence components of current The expression of three-phase voltage unbalance is: , where U0 is the RMS value of the negative sequence voltage component, U1 is the RMS value of the positive sequence voltage component, and the three-phase current unbalance expression is: , where P0 is the RMS value of the negative sequence current component, and P1 is the RMS value of the positive sequence current component.

[0011] Furthermore, the voltage fluctuation calculation content is: Take the relative percentage of the ratio of the difference between two adjacent extreme values ​​of the voltage root mean square value change to the nominal voltage; By formula The voltage fluctuation value is obtained, where Umax and Umin are two adjacent extreme values ​​in the voltage root mean square value change, and Ub is the nominal voltage.

[0012] Furthermore, the voltage total harmonic distortion rate is calculated as follows: Obtain the effective value of each harmonic amplitude and the effective value of the fundamental amplitude; According to the formula The total harmonic distortion rate of the voltage is obtained, where Uk is the effective value of the amplitude of each harmonic, Uz is the effective value of the fundamental amplitude, and m is the preset highest order of the harmonic.

[0013] Furthermore, the quality affiliation analysis unit evaluates the integration process in the following manner: Obtain calculation information of the power quality calculation unit, including voltage deviation, frequency deviation, three-phase voltage unbalance, voltage fluctuation and voltage total harmonic distortion rate; Compare and analyze the preset index values ​​with the calculated information of the obtained power quality calculation unit one by one, and the index values ​​include voltage deviation index, voltage fluctuation index, three-phase voltage imbalance index, voltage total harmonic distortion rate index and frequency deviation index; When the values ​​of all the calculated information do not exceed the corresponding index values ​​of each item, it is determined to be in a qualified state. When one or more of the values ​​of all the calculated information exceed the corresponding index, it is determined to be in an unqualified state.

[0014] Comprehensive quality assessment is achieved by comparing and analyzing the preset indicator values ​​with the calculation information of the acquired power quality calculation unit one by one.

[0015] Furthermore, the budget processing method of the trend prediction unit is: Obtain the voltage deviation, frequency deviation, three-phase voltage unbalance, voltage fluctuation and voltage total harmonic distortion rate of the last three times with a time difference of 24 hours, and perform estimated calculations on the voltage deviation, frequency deviation, three-phase voltage unbalance, voltage fluctuation and voltage total harmonic distortion rate respectively; The voltage deviation is estimated by the formula Get the estimated voltage deviation after 24 hours, where: is the voltage deviation of the last three times. is the voltage deviation of the second of the last three times, is the voltage deviation for the first time in the last three times; according to , Comparative judgment, when When the voltage deviation warning information is generated; The estimated calculation method of frequency deviation, three-phase voltage unbalance, voltage fluctuation and voltage total harmonic distortion rate refers to the above-mentioned voltage deviation estimated calculation method.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. By comparing and analyzing the preset index values ​​with the calculated information of the power quality calculation unit, a comprehensive quality assessment can be performed based on voltage deviation, frequency deviation, three-phase voltage imbalance, voltage fluctuation, voltage total harmonic distortion rate and their corresponding indicators, which is faster and more comprehensive.

[0017] 2. The voltage deviation, frequency deviation, three-phase voltage imbalance, voltage fluctuation and voltage total harmonic distortion rate can be estimated and calculated based on past parameters, thereby realizing the power quality assessment and early warning function. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0019] Figure 1 It is a system composition diagram of the present invention. DETAILED DESCRIPTION

[0020] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] See also Figure 1 As shown, a power engineering quality assessment and early warning system based on data analysis includes a monitoring unit, a database, a power quality calculation unit, a quality affiliation analysis unit, and a trend prediction unit; The monitoring unit includes a voltage monitoring module, a frequency monitoring module, a three-phase voltage monitoring module, and a power grid harmonic monitoring module. The voltage monitoring module is used to obtain the actual voltage value, the frequency monitoring module is used to obtain the actual value of the power grid system frequency, the three voltage monitoring modules are used to obtain the root mean square values ​​of the positive and negative sequence components of the voltage, and the power grid harmonic monitoring module is used to obtain the harmonic information of the power grid system. The monitoring unit is used to transmit the information to a database, and the database saves the information and attaches keywords and timestamps. The power quality calculation unit is composed of a voltage quality module, a frequency quality module, three voltage quality modules, a power grid harmonic quality module, and a voltage fluctuation module. The power quality calculation unit is used to perform classified quality calculation processing according to keywords, and the classified quality calculation processing includes voltage deviation calculation, frequency deviation calculation, three-phase load imbalance calculation, voltage fluctuation calculation, and voltage total harmonic distortion rate calculation; The steps for calculating the above voltage deviation are: Get the actual voltage and the system nominal voltage; The voltage deviation is obtained based on the percentage of the difference between the actual voltage and the system nominal voltage and the ratio of the system nominal voltage. Its expression is: , where SU is the voltage deviation, Ua is the actual voltage, and Ub is the system nominal voltage; The steps for calculating the frequency deviation are: Get the actual frequency and the system nominal frequency The frequency deviation is obtained by the formula F=fa-fb, where F is the frequency deviation, fa is the actual frequency, and fb is the nominal frequency of the system; The steps for calculating the three-phase load imbalance are: Get the RMS value of the positive and negative sequence components of voltage, and get the RMS value of the positive and negative sequence components of current The expression of three-phase voltage unbalance is: , where U0 is the RMS value of the negative sequence voltage component, U1 is the RMS value of the positive sequence voltage component, and the three-phase current unbalance expression is: , where P0 is the RMS value of the negative sequence component of the current, and P1 is the RMS value of the positive sequence component of the current. Three-phase balance is particularly important for the power system. When the power system is in three-phase unbalanced operation, its voltage and current contain a large amount of negative sequence components. The three-phase imbalance will cause additional heating and vibration of the rotating motor, causing the occurrence of various protection malfunctions with negative sequence components as starting elements, resulting in additional harmonic currents in semiconductor equipment, reducing the capacity utilization of the generator, thereby affecting the normal operation of the computer, causing an increase in power grid losses, and increasing interference to the communication system; The content of voltage fluctuation calculation is: Take the relative percentage of the ratio of the difference between two adjacent extreme values ​​of the voltage root mean square value change to the nominal voltage; By formula The voltage fluctuation value is obtained, where Umax and Umin are two adjacent extreme values ​​in the voltage root mean square value change, and Ub is the nominal voltage; The voltage total harmonic distortion rate is calculated as follows: Obtain the effective value of each harmonic amplitude and the effective value of the fundamental amplitude; According to the formula The total harmonic distortion rate of voltage is obtained, where Uk is the effective value of each harmonic amplitude, Uz is the effective value of the fundamental amplitude, and m is the preset maximum order of harmonics. The nonlinear load in the power system is the main source of waveform distortion. The hazards of harmonic pollution are mainly reflected in the interference and influence on power and signals. The hazards to electricity mainly include: causing additional losses and heating of rotating motors and transformers, shortening their service life; harmonic resonance overvoltage causes failure and damage of electrical components and equipment; making the original definition and method of electric energy measurement inapplicable.

[0022] The quality membership analysis unit is used to perform evaluation and integration processing based on the output information of the power quality calculation unit, and the trend estimation unit is used to perform budget processing based on historical information; The above quality affiliation analysis unit evaluation and integration processing method is as follows: Obtain calculation information of the power quality calculation unit, including voltage deviation, frequency deviation, three-phase voltage unbalance, voltage fluctuation and voltage total harmonic distortion rate; Compare and analyze the preset index values ​​with the calculated information of the obtained power quality calculation unit one by one, and the index values ​​include voltage deviation index, voltage fluctuation index, three-phase voltage imbalance index, voltage total harmonic distortion rate index and frequency deviation index; When the values ​​of all calculated information do not exceed the corresponding index values, it is judged to be qualified. When one or more of the values ​​of all calculated information exceed the corresponding index, it is judged to be unqualified. It can conduct comprehensive quality assessment based on voltage deviation, frequency deviation, three-phase voltage imbalance, voltage fluctuation and voltage total harmonic distortion rate and their corresponding indicators, which is faster and more comprehensive.

[0023] The budget processing method of the trend prediction unit is: Obtain the voltage deviation, frequency deviation, three-phase voltage unbalance, voltage fluctuation and voltage total harmonic distortion rate of the last three times with a time difference of 24 hours, and perform estimated calculations on the voltage deviation, frequency deviation, three-phase voltage unbalance, voltage fluctuation and voltage total harmonic distortion rate respectively; The voltage deviation is estimated by the formula Get the estimated voltage deviation after 24 hours, where: is the voltage deviation of the last three times. is the voltage deviation of the second of the last three times, is the voltage deviation for the first time in the last three times; according to , Comparative judgment, when When the voltage deviation warning information is generated; The specific method for estimating voltage deviation is to obtain the voltage deviations of the last three times, the first voltage deviation, the second voltage deviation, and the third voltage deviation. The voltage deviation interval is 24 hours, that is, the first voltage deviation is 24 hours away from the second voltage deviation, and the second voltage deviation is 24 hours away from the third voltage deviation. When the first voltage deviation, the second voltage deviation, and the third voltage deviation are 4%, 5%, and 6% respectively, the values ​​are substituted into the formula for calculation as (6%-5%) + (5%-4%) + 6% = 8%, and 8% represents the estimated next voltage deviation value. At this time, if 8% is greater than the nominal voltage, a voltage deviation warning message is issued, thereby achieving a warning effect.

[0024] The estimated calculation method of frequency deviation, three-phase voltage unbalance, voltage fluctuation and voltage total harmonic distortion rate refers to the above-mentioned voltage deviation estimated calculation method, and finally achieves the early warning purpose of frequency deviation, three-phase voltage unbalance, voltage fluctuation and voltage total harmonic distortion rate, thereby realizing the function of power quality assessment and early warning.

[0025] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A power engineering quality assessment and early warning system based on data analysis, characterized in that: It includes monitoring unit, database, power quality calculation unit, quality affiliation analysis unit and trend prediction unit; The monitoring unit includes a voltage monitoring module, a frequency monitoring module, a three-phase voltage monitoring module, and a power grid harmonic monitoring module. The voltage monitoring module is used to obtain the actual voltage value, the frequency monitoring module is used to obtain the actual value of the power grid system frequency, the three voltage monitoring modules are used to obtain the root mean square values ​​of the positive and negative sequence components of the voltage, and the power grid harmonic monitoring module is used to obtain the harmonic information of the power grid system. The monitoring unit is used to transmit the information to a database, and the database saves the information and attaches keywords and timestamps. The power quality calculation unit is composed of a voltage quality module, a frequency quality module, three voltage quality modules, a power grid harmonic quality module, and a voltage fluctuation module. The power quality calculation unit is used to perform classified quality calculation processing according to keywords, and the classified quality calculation processing includes voltage deviation calculation, frequency deviation calculation, three-phase load imbalance calculation, voltage fluctuation calculation, and voltage total harmonic distortion rate calculation; The quality membership analysis unit is used to perform evaluation and integration processing based on the output information of the power quality calculation unit, and the trend prediction unit is used to perform budget processing based on historical information.

2. According to the data analysis-based power engineering quality assessment and early warning system of claim 1, it is characterized in that: The steps of calculating the voltage deviation are: Get the actual voltage and the system nominal voltage; The voltage deviation is obtained based on the percentage of the difference between the actual voltage and the system nominal voltage and the ratio of the system nominal voltage. Its expression is: , where SU is the voltage deviation, Ua is the actual voltage, and Ub is the system nominal voltage.

3. The power engineering quality assessment and early warning system based on data analysis according to claim 2 is characterized in that: The steps of calculating the frequency deviation are: Get the actual frequency and the system nominal frequency The frequency deviation is obtained by the formula F=fa-fb, where F is the frequency deviation, fa is the actual frequency, and fb is the system nominal frequency.

4. The power engineering quality assessment and early warning system based on data analysis according to claim 3 is characterized in that: The steps of calculating the three-phase load imbalance are: Get the RMS value of the positive and negative sequence components of voltage, and get the RMS value of the positive and negative sequence components of current The expression of three-phase voltage unbalance is: , where U0 is the RMS value of the negative sequence voltage component, U1 is the RMS value of the positive sequence voltage component, and the three-phase current unbalance expression is: , where P0 is the RMS value of the negative sequence current component, and P1 is the RMS value of the positive sequence current component.

5. The power engineering quality assessment and early warning system based on data analysis according to claim 4 is characterized in that: The content of the voltage fluctuation calculation is: Take the relative percentage of the ratio of the difference between two adjacent extreme values ​​of the voltage root mean square value change to the nominal voltage; By formula The voltage fluctuation value is obtained, where Umax and Umin are two adjacent extreme values ​​in the voltage root mean square value change, and Ub is the nominal voltage.

6. The power engineering quality assessment and early warning system based on data analysis according to claim 5 is characterized in that: The voltage total harmonic distortion rate is calculated as follows: Obtain the effective value of each harmonic amplitude and the effective value of the fundamental amplitude; According to the formula The total harmonic distortion rate of the voltage is obtained, where Uk is the effective value of the amplitude of each harmonic, Uz is the effective value of the fundamental amplitude, and m is the preset highest order of the harmonic.

7. The power engineering quality assessment and early warning system based on data analysis according to claim 6 is characterized in that: The quality membership analysis unit evaluates the integration process in the following way: Obtain calculation information of the power quality calculation unit, including voltage deviation, frequency deviation, three-phase voltage unbalance, voltage fluctuation and voltage total harmonic distortion rate; Compare and analyze the preset index values ​​with the calculated information of the obtained power quality calculation unit one by one, and the index values ​​include voltage deviation index, voltage fluctuation index, three-phase voltage imbalance index, voltage total harmonic distortion rate index and frequency deviation index; When the values ​​of all the calculated information do not exceed the corresponding index values ​​of each item, it is determined to be in a qualified state. When one or more of the values ​​of all the calculated information exceed the corresponding index, it is determined to be in an unqualified state.

8. The power engineering quality assessment and early warning system based on data analysis according to claim 7 is characterized in that: The budget processing method of the trend prediction unit is: Obtain the voltage deviation, frequency deviation, three-phase voltage unbalance, voltage fluctuation and voltage total harmonic distortion rate of the last three times with a time difference of 24 hours, and perform estimated calculations on the voltage deviation, frequency deviation, three-phase voltage unbalance, voltage fluctuation and voltage total harmonic distortion rate respectively; The voltage deviation is estimated by the formula Get the estimated voltage deviation after 24 hours, where: is the voltage deviation of the last three times. is the voltage deviation of the second of the last three times, is the voltage deviation for the first time in the last three times; according to , Comparative judgment, when When the voltage deviation warning information is generated; The estimated calculation method of frequency deviation, three-phase voltage unbalance, voltage fluctuation and voltage total harmonic distortion rate refers to the above-mentioned voltage deviation estimated calculation method.

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