A reactive power compensation method and system based on historical data

Abstract

The present invention discloses a reactive power compensation method and system based on historical data. The system includes a data acquisition unit, a data processing unit, a data storage unit, and a central control unit. The data acquisition unit, the data processing unit, and the central control unit are each communicatively connected to the data storage unit, and a central control power supply is each communicatively connected to the data acquisition unit and the data processing unit. The present invention utilizes historical power grid data to calculate the fluctuation percentages of the power grid's active power, the power factor, and the reactive power compensation switching capacity over the same period and the recent period, thereby deriving a trend factor related to reactive power compensation. The trend factor is then used to adjust the reactive power compensation switching capacity during reactive power compensation operations, thereby increasing the duration of reactive power compensation effectiveness.

Description

Technical Field

[0001] The present invention relates to the technical field of reactive power compensation, and more particularly to a reactive power compensation method and system based on historical data. Background Art

[0002] To reduce grid power consumption and improve grid quality, reactive power compensation is used to maintain a high power factor. Existing reactive power compensation is typically performed based on the current grid operating status, allowing for timely adjustments to the power factor. However, these adjustments typically occur when the power factor has exceeded a preset range. Switching the reactive power compensation device on and off at this point can significantly impact the grid.

[0003] In order to cope with the expected power factor changes in the power grid, people use a method of jointly analyzing historical data and current power grid data to control reactive compensation operations. However, existing reactive compensation control technologies based on historical data and current power grid data usually use historical data to determine the changing trend of the power grid operating status in the same period, and then predict the allowable state of the power grid at a certain time in the future, but ignore the irregular fluctuations in the power grid operating conditions. This will result in the need for another switching operation shortly after the reactive compensation device is put into operation or cut out. Therefore, how to use the historical data of the power grid to serve the current reactive compensation switching operation to reduce invalid or inefficient reactive compensation device switching operations. Summary of the Invention

[0004] To this end, the technical problem to be solved by the present invention is to provide a reactive power compensation method and system based on historical data, which uses the historical data of the power grid to calculate the fluctuation percentage of the active power of the power grid in the recent period, the fluctuation percentage of the power factor of the power grid and the fluctuation percentage of the reactive compensation switching amount, and then derives the trend factor related to the reactive compensation. When performing reactive compensation operations, the trend factor is used to adjust the reactive compensation switching amount to improve the duration of the effectiveness of reactive compensation.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A reactive power compensation method based on historical data includes the following steps:

[0007] S100) Data Collection: Using time point t0 as the data collection base point, collect grid data DATA1 related to grid reactive power compensation for at least one week before and after the same date in the previous year, and collect grid data DATA2 related to grid reactive power compensation for a period of at least three months going back from time point t0; both grid data DATA1 and grid data DATA2 include grid active power, grid power factor, and reactive power compensation switching capacity;

[0008] S200) Data processing: Calculate the trend factor ζ1 using the fluctuation percentage of the grid active power, the fluctuation percentage of the grid power factor, and the fluctuation percentage of the reactive compensation switching amount in the grid data DATA1, and calculate the trend factor ζ2 using the fluctuation percentage of the grid active power, the fluctuation percentage of the grid power factor, and the fluctuation percentage of the reactive compensation switching amount in the grid data DATA2. Then, calculate the composite trend factor ζ using the following formula: 复合 :

[0009]

[0010] Wherein, m and n are both rational numbers greater than 1, and nm is greater than or equal to 0.5;

[0011] S300) Switching operation: When a switching operation is required at time point t0, the switching is performed according to the following strategy:

[0012] Strategy 1) When reactive power compensation units are required, calculate the reactive power compensation switching capacity according to the following formula: :

[0013]

[0014] In the formula, Qc 投 The reactive power compensation switching amount that should be invested is calculated using the grid data at time point t0;

[0015] Strategy 2) When the reactive compensation unit needs to be switched off, the reactive compensation switching amount is calculated according to the following formula: :

[0016]

[0017] In the formula, Qc 切 The reactive compensation switching amount that should be switched out is calculated using the grid data at time point t0.

[0018] In the reactive power compensation method based on historical data, in step S200), the trend factor ζ1 is calculated using the power grid data DATA1 and the following formula:

[0019]

[0020] Where, 、 and They are calculated by the following formulas:

[0021]

[0022]

[0023]

[0024] Where, α 1-t0 is the absolute average value of the fluctuation percentage of the grid active power at the same time point as time point t0 in the grid data DATA1; 1-h is the absolute average value of the fluctuation percentage of the daily grid active power mean in the grid data DATA1; β 1-t0 β is the absolute average value of the fluctuation percentage of the power factor of the power grid at the same time point as time point t0 in the power grid data DATA1; 1-h is the absolute average value of the fluctuation percentage of the daily power factor in the power grid data DATA1; 1-t0 is the absolute average value of the fluctuation percentage of the reactive compensation switching amount at the same time point as time point t0 in the power grid data DATA1; 1-h It is the absolute average value of the fluctuation percentage of the daily reactive compensation switching amount in the power grid data DATA1.

[0025] In the reactive power compensation method based on historical data, in step S200), the trend factor ζ2 is calculated using the power grid data DATA2 and the following formula:

[0026]

[0027] Where, 、 and They are calculated by the following formulas:

[0028]

[0029]

[0030]

[0031] Where, α 2-t0 is the absolute average value of the fluctuation percentage of the grid active power at the same time point as time point t0 in the grid data DATA2; 2-h is the absolute average value of the fluctuation percentage of the daily grid active power mean in the grid data DATA2; β 2-t0 β is the absolute average value of the fluctuation percentage of the power factor at the same time point as time point t0 in the power grid data DATA2; 2-h is the absolute average value of the fluctuation percentage of the daily power factor in the power grid data DATA2; 2-t0 is the absolute average value of the fluctuation percentage of the reactive compensation switching amount at the same time point as time point t0 in the power grid data DATA2; 2-hIt is the absolute average value of the fluctuation percentage of the daily reactive compensation switching amount in the power grid data DATA2.

[0032] The reactive power compensation method based on historical data, in step S200), is to calculate the reactive power compensation value according to the time period of the reactive power compensation switching operation. 复合 Make corrections, the specific formula is as follows:

[0033]

[0034] Where δ is the correction factor, which is calculated by the following formula:

[0035]

[0036] Where x, y, and z are preset parameters, where the value range of x is [2.25, 2.45], the value range of y is [3, 3.2], and the value range of z is [2.5, 2.7].

[0037] In the reactive power compensation method based on historical data, yx is greater than or equal to 0.6 and less than or equal to 0.9.

[0038] In the reactive power compensation method based on historical data, yx is greater than or equal to 0.2 and less than or equal to 0.4.

[0039] In the reactive power compensation method based on historical data, in step S300), when the switching operation is performed, when the active power in the grid data DATA1 and the grid data DATA2 are both in the rising stage, the calculated reactive power compensation switching amount Adjust downwards by 0.1 to 0.15, or change the calculated reactive compensation switching amount Adjust upwards with an adjustment range of 0.05 to 0.1. When the active power in the grid data DATA1 and the grid data DATA2 are both in the decreasing stage, the calculated reactive compensation switching amount Adjust upwards by 0.05 to 0.15, or adjust the calculated reactive compensation switching amount Adjust downwards, the adjustment range is 0.05~0.1; when the active power change trend in the grid data DATA1 is different from the active power change trend in the grid data DATA2, the reactive power compensation switching amount will not be adjusted. and reactive compensation switching capacity Make adjustments.

[0040] A system for performing reactive power compensation using the reactive power compensation method based on historical data, comprising:

[0041] A data acquisition unit, used to collect grid data related to grid reactive compensation;

[0042] A data processing unit, used for processing the data collected by the data collection unit;

[0043] A data storage unit, used to store data collected by the data collection unit and data processing results of the data processing unit;

[0044] A central control unit, used for controlling the switching of the reactive compensation unit according to the data processing result of the data processing unit;

[0045] The data acquisition unit and the data storage unit are respectively connected to the data storage unit for communication, and the data storage unit is connected to the control unit for communication.

[0046] The above system also includes an alarm unit for prompting the switching operation and notifying the switching operation result.

[0047] The above system also includes a display unit for displaying the operating status of the power grid and the switching status of the reactive compensation unit. The display unit is a hardware terminal or a software terminal.

[0048] The technical solution of the present invention achieves the following beneficial technical effects:

[0049] 1. The present invention uses trend factors related to fluctuations in grid active power, grid power factor, and reactive compensation switching to adjust reactive compensation switching. This reduces the frequency of reactive compensation switching operations caused by fluctuations in grid operating conditions within a short period (usually half an hour), thereby improving grid operational stability.

[0050] 2. The trend factor ζ is adjusted according to the different loads of the power grid at different times within 24 hours. 复合 By making corrections to varying degrees, the technology of using trend factors to adjust reactive compensation switching can be better applied to scenarios where the grid operation conditions vary significantly with human work and rest schedules. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is a schematic diagram of the working principle of the reactive power compensation system based on historical data;

[0052] Figure 2 This is a flow chart of reactive power compensation based on historical data. DETAILED DESCRIPTION

[0053] In the field of power supply, historical data is a valuable reference for monitoring the operation of power grids and can be used for services such as power grid fault detection and power grid operation control. However, due to the rapid increase in power consumption in recent years, when historical data is used for reactive power compensation control, areas with relatively small increases in power consumption compared to the same period are usually selected. For areas with large increases in power consumption compared to the same period, it is difficult to use historical data as a reference for reactive power compensation control. In view of this, the present invention introduces a trend factor to weaken the direct impact of historical data on reactive power compensation control, while strengthening the combined impact of historical data on reactive power compensation control.

[0054] Specifically, if Figure 1 As shown, the reactive power compensation system based on historical data in the present invention includes a data acquisition unit, a data processing unit, a data storage unit, a central control unit, an alarm unit and a display unit. The data acquisition unit, the data processing unit and the central control unit are respectively connected to the data storage unit in communication, and the central control power supply is respectively connected to the data acquisition unit, the data processing unit, the alarm unit and the display unit in communication. Among them, the data acquisition unit is used to collect grid data related to reactive power compensation of the power grid; the data processing unit is used to process the data collected by the data acquisition unit; the data storage unit is used to store the data collected by the data acquisition unit and the data processing results of the data processing unit; the central control unit is used to control the switching of the reactive power compensation unit according to the data processing results of the data processing unit; the alarm unit is used to notify the switching operation and the switching operation results; the display unit is used to display the operation status of the power grid and the switching status of the reactive power compensation unit. The display unit is a hardware terminal or a software terminal, such as a PC or an APP.

[0055] When applying the historical data-based reactive power compensation system of the present invention to reactive power compensation control in a power grid, historical grid data for a substation that has been in operation for more than one year should be input. For newly built substations or substations that have been in operation for less than one year, historical grid data from neighboring substations can be input as reference data. Therefore, the present invention will only use an existing substation power grid as an example for description.

[0056] like Figure 2 As shown, when the reactive power compensation system based on historical data in the present invention is used for reactive power compensation, the reactive power compensation operation is implemented through the following steps:

[0057] S100) Data collection: With time point t0 as the data collection base point, collect power grid data DATA1 related to power grid reactive power compensation for at least one week before and after the same date in the previous year, and collect power grid data DATA2 related to power grid reactive power compensation for a period of at least three months going back from time point t0; wherein both power grid data DATA1 and power grid data DATA2 include power grid active power, power grid power factor, and reactive power compensation switching amount.

[0058] In view of the change in the strength of referenceability and the consideration of the increase in calculation amount, in the present invention, it is preferred to collect the power grid data DATA1 related to the reactive power compensation of the power grid one week before and after the same date of the previous year, and collect the power grid data DATA2 related to the reactive power compensation of the power grid within a period of three months from the date of time point t0. At this time, there is a strong reference between the power grid data DATA1 and the power grid data DATA2 and the power grid data DATA0 at the time point t0, and the calculation amount is not large.

[0059] S200) Data processing: Calculate the trend factor ζ1 using the fluctuation percentage of the grid active power, the fluctuation percentage of the grid power factor, and the fluctuation percentage of the reactive compensation switching amount in the grid data DATA1, and calculate the trend factor ζ2 using the fluctuation percentage of the grid active power, the fluctuation percentage of the grid power factor, and the fluctuation percentage of the reactive compensation switching amount in the grid data DATA2. Then, calculate the composite trend factor ζ using the following formula: 复合 :

[0060]

[0061] Wherein, m and n are both rational numbers greater than 1, and nm is greater than or equal to 0.5.

[0062] The trend factor ζ1 can be calculated using the power grid data DATA1 and the following formula:

[0063]

[0064] Where, 、 and They are calculated by the following formulas:

[0065]

[0066]

[0067]

[0068] Where, α 1-t0is the absolute average value of the fluctuation percentage of the grid active power at the same time point as time point t0 in the grid data DATA1; 1-h is the absolute average value of the fluctuation percentage of the daily grid active power mean in the grid data DATA1; β 1-t0 β is the absolute average value of the fluctuation percentage of the power factor of the power grid at the same time point as time point t0 in the power grid data DATA1; 1-h is the absolute average value of the fluctuation percentage of the daily power factor in the power grid data DATA1; 1-t0 is the absolute average value of the fluctuation percentage of the reactive compensation switching amount at the same time point as time point t0 in the power grid data DATA1; 1-h It is the absolute average value of the fluctuation percentage of the daily reactive compensation switching amount in the power grid data DATA1.

[0069] The trend factor ζ2 can be calculated using the power grid data DATA2 and the following formula:

[0070]

[0071] Where, 、 and They are calculated by the following formulas:

[0072]

[0073]

[0074]

[0075] Where, α 2-t0 is the absolute average value of the fluctuation percentage of the grid active power at the same time point as time point t0 in the grid data DATA2; 2-h is the absolute average value of the fluctuation percentage of the daily grid active power mean in the grid data DATA2; β 2-t0 β is the absolute average value of the fluctuation percentage of the power factor at the same time point as time point t0 in the power grid data DATA2; 2-h is the absolute average value of the fluctuation percentage of the daily power factor in the power grid data DATA2; 2-t0 is the absolute average value of the fluctuation percentage of the reactive compensation switching amount at the same time point as time point t0 in the power grid data DATA2; 2-h It is the absolute average value of the fluctuation percentage of the daily reactive compensation switching amount in the power grid data DATA2.

[0076] In the present invention, the absolute average of the fluctuation percentages of the grid's active power, power factor, and reactive compensation switching capacity in different reference frames is used as input for calculating trend factors ζ1 and ζ2. This takes into account the irregularities in the start-up and shutdown of some electrical equipment in the substation area, as well as the irregularities in the movement of some electrical equipment in the substation area. This can cause significant changes in the grid's active power, but the power factor and reactive compensation switching capacity do not necessarily fluctuate significantly. Only when high-power equipment is started and stopped, or moved in and out, can the power factor fluctuate significantly, affecting the increase or decrease in reactive compensation switching capacity. Furthermore, the influence of the reactive compensation switching capacity on the reactive compensation performed at time point t0 on the power factor change and reactive compensation switching capacity in the historical data is greater. Therefore, the weight of the power factor change and reactive compensation switching capacity change in the historical data is increased when calculating trend factors ζ1 and ζ2.

[0077] For areas where the active power and power factor of the power grid change significantly with the change of people's activity time, it is necessary to consider the adjustment of the power factor at different time periods. 复合 To cope with the possible power fluctuations, specifically, in step S200), the reactive compensation switching operation is performed according to the time period of the reactive compensation switching operation. 复合 Make corrections, the specific formula is as follows:

[0078]

[0079] Where δ is the correction factor, which is calculated by the following formula:

[0080]

[0081] Wherein, x, y, and z are preset parameters, which are set by the user according to the grid operation status of the substation. The value range of x is [2.25, 2.45], the value range of y is [3, 3.2], and the value range of z is [2.5, 2.7]. Preferably, yx is greater than or equal to 0.6 and less than or equal to 0.9, and yx is greater than or equal to 0.2 and less than or equal to 0.4.

[0082] S300) Switching operation: When a switching operation is required at time point t0, the switching is performed according to the following strategy:

[0083] Strategy 1) When reactive power compensation units are required, calculate the reactive power compensation switching capacity according to the following formula: :

[0084]

[0085] In the formula, Qc 投The reactive power compensation switching amount that should be invested is calculated using the grid data at time point t0;

[0086] Strategy 2) When the reactive compensation unit needs to be switched off, the reactive compensation switching amount is calculated according to the following formula: :

[0087]

[0088] In the formula, Qc 切 The reactive compensation switching amount that should be switched out is calculated using the grid data at time point t0.

[0089] In step S300), when the trend factor ζ 复合 When the trend factor ζ used in strategies 1) and 2) is corrected 复合 A modified trend factor should also be used.

[0090] In order to further prevent the current switching operation from burdening subsequent switching operations (such as increasing the switching frequency in a short period of time), the reactive compensation switching amount in the switching operation should be adjusted to a certain extent based on the trend of grid active power changes in historical data. Specifically:

[0091] During the switching operation, when the active power in the grid data DATA1 and the grid data DATA2 are both in the rising stage, the calculated reactive compensation switching amount Adjust downwards, the adjustment range is 0.1~0.15, preferably 0.12~0.14, or the calculated reactive compensation switching amount Adjust upwards, the adjustment range is 0.05~0.1, preferably 0.7~0.09; when the active power in the grid data DATA1 and the grid data DATA2 are both in the decreasing stage, the calculated reactive compensation switching amount Adjust upwards, the adjustment range is 0.05~0.15, preferably 0.09~0.12, or the calculated reactive compensation switching amount Adjust downward, the adjustment range is 0.05~0.1, preferably 0.6~0.07; when the active power change trend in the grid data DATA1 is different from the active power change trend in the grid data DATA2, the reactive power compensation switching amount is not adjusted. and reactive compensation switching capacity Make adjustments.

[0092] In the reactive compensation simulation test using the reactive compensation method based on historical data in the present invention, not only the frequency of switching operations is reduced, especially when the power factor fluctuates multiple times, but also the reactive compensation switching amount Qc is reduced. 切The correction can make a reactive compensation switching operation have a certain buffering capacity for small changes in power factor, that is, the power factor change amplitude that occurs under the original reactive compensation switching operation can be reduced, so that the power factor after the change is still within a reasonable threshold range when a small change occurs, thereby extending the interval time between two adjacent switching operations. For example, when it is necessary to put the reactive compensation unit into operation, the reactive compensation switching amount that should be put into operation calculated according to the grid data at time point t0 is 1, and when the active power in the grid data DATA1 and the grid data DATA2 are both in the rising stage, the corrected is 0.89, at this time, Qc 投 and The difference between them is to cope with the increase of active power in a certain period of time in the future, so that the grid can have a certain degree of active power increase in this period of time, and there is no need to cut out the reactive compensation unit from the grid power supply system.

[0093] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the claims of this patent application.

Claims

1. A reactive power compensation method based on historical data, characterized in that: The steps include: S100) Data Collection: Using time point t0 as the data collection base point, collect grid data DATA1 related to grid reactive power compensation for at least one week before and after the same date in the previous year, and collect grid data DATA2 related to grid reactive power compensation for a period of at least three months going back from time point t0; both grid data DATA1 and grid data DATA2 include grid active power, grid power factor, and reactive power compensation switching capacity; S200) Data processing: Calculate the trend factor ζ1 using the fluctuation percentage of the grid active power, the fluctuation percentage of the grid power factor, and the fluctuation percentage of the reactive compensation switching amount in the grid data DATA1, and calculate the trend factor ζ2 using the fluctuation percentage of the grid active power, the fluctuation percentage of the grid power factor, and the fluctuation percentage of the reactive compensation switching amount in the grid data DATA2. Then, calculate the composite trend factor ζ using the following formula: 复合 : Wherein, m and n are both rational numbers greater than 1, and nm is greater than or equal to 0.5; S300) Switching operation: When a switching operation is required at time point t0, the switching is performed according to the following strategy: Strategy 1) When reactive power compensation units are required, calculate the reactive power compensation switching capacity according to the following formula: : In the formula, Qc 投 The reactive power compensation switching amount that should be invested is calculated using the grid data at time point t0; Strategy 2) When the reactive compensation unit needs to be switched off, the reactive compensation switching amount is calculated according to the following formula: : In the formula, Qc 切 The reactive compensation switching amount that should be switched out is calculated using the grid data at time point t0.

2. The reactive power compensation method based on historical data according to claim 1, characterized in that: In step S200), the trend factor ζ1 is calculated using the power grid data DATA1 and the following formula: Where, 、 and They are calculated by the following formulas: Where, α 1-t0 is the absolute average value of the fluctuation percentage of the grid active power at the same time point as time point t0 in the grid data DATA1; 1-h is the absolute average value of the fluctuation percentage of the daily grid active power mean in the grid data DATA1; β 1-t0 β is the absolute average value of the fluctuation percentage of the power factor of the power grid at the same time point as time point t0 in the power grid data DATA1; 1-h is the absolute average value of the fluctuation percentage of the daily power factor in the power grid data DATA1; 1-t0 is the absolute average value of the fluctuation percentage of the reactive compensation switching amount at the same time point as time point t0 in the power grid data DATA1; 1-h It is the absolute average value of the fluctuation percentage of the daily reactive compensation switching amount in the power grid data DATA1.

3. The reactive power compensation method based on historical data according to claim 1, characterized in that: In step S200), the trend factor ζ2 is calculated using the power grid data DATA2 and the following formula: Where, 、 and They are calculated by the following formulas: Where, α 2-t0 is the absolute average value of the fluctuation percentage of the grid active power at the same time point as time point t0 in the grid data DATA2; 2-h is the absolute average value of the fluctuation percentage of the daily grid active power mean in the grid data DATA2; β 2-t0 β is the absolute average value of the fluctuation percentage of the power factor at the same time point as time point t0 in the power grid data DATA2; 2-h is the absolute average value of the fluctuation percentage of the daily power factor in the power grid data DATA2; 2-t0 is the absolute average value of the fluctuation percentage of the reactive compensation switching amount at the same time point as time point t0 in the power grid data DATA2; 2-h It is the absolute average value of the fluctuation percentage of the daily reactive compensation switching amount in the power grid data DATA2.

4. The reactive power compensation method based on historical data according to claim 1, characterized in that: In step S200), the switching operation of reactive power compensation is performed according to the time period. 复合 Make corrections, the specific formula is as follows: Where δ is the correction factor, which is calculated by the following formula: Where x, y, and z are preset parameters, where the value range of x is [2.25, 2.45], the value range of y is [3, 3.2], and the value range of z is [2.5, 2.7].

5. The reactive power compensation method based on historical data according to claim 4, characterized in that: yx is greater than or equal to 0.6 and less than or equal to 0.

9.

6. The reactive power compensation method based on historical data according to claim 4, characterized in that: yx is greater than or equal to 0.2 and less than or equal to 0.

4.

7. The reactive power compensation method based on historical data according to claim 1, characterized in that: In step S300), when the switching operation is performed, when the active power in the grid data DATA1 and the grid data DATA2 are both in the rising stage, the calculated reactive compensation switching amount Adjust downwards by 0.1 to 0.15, or change the calculated reactive compensation switching amount Adjust upwards with an adjustment range of 0.05 to 0.

1. When the active power in the grid data DATA1 and the grid data DATA2 are both in the decreasing stage, the calculated reactive compensation switching amount Adjust upwards by 0.05 to 0.15, or adjust the calculated reactive compensation switching amount Adjust downwards, the adjustment range is 0.05~0.1; when the active power change trend in the grid data DATA1 is different from the active power change trend in the grid data DATA2, the reactive power compensation switching amount will not be adjusted. and reactive compensation switching capacity Make adjustments.

8. A system for performing reactive power compensation using the reactive power compensation method based on historical data according to claim 1, characterized in that: include: A data acquisition unit, used to collect grid data related to grid reactive compensation; A data processing unit, used for processing the data collected by the data collection unit; A data storage unit, used to store data collected by the data collection unit and data processing results of the data processing unit; A central control unit, used for controlling the switching of the reactive compensation unit according to the data processing result of the data processing unit; The data acquisition unit and the data storage unit are respectively connected to the data storage unit for communication, and the data storage unit is connected to the control unit for communication.

9. The system according to claim 8, characterized in that It also includes an alarm unit for prompting switching operations and notifying switching operation results.

10. The system according to claim 8, wherein: It also includes a display unit for displaying the operating status of the power grid and the switching status of the reactive compensation unit.

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