Low-frequency oscillation false alarm detection method and system combined with series-parallel connection relation

Abstract

The invention discloses a low-frequency oscillation false alarm detection method and system combined with a series-parallel connection relation, and the method comprises the steps: obtaining the real-time operation data of a power grid, and searching a line set directly connected with an oscillation alarm line according to a power grid extension connection relation in the real-time operation data of the power grid; acquiring line operation power, calculating distribution factors among lines in the line set, judging a series-parallel connection relation between the oscillation alarm line and the connected lines, and incorporating the lines in the series connection relation into a series line set; the oscillation amplitude of each line in the series line set is calculated, and the oscillation early warning proportion is calculated based on the number of oscillation early warning lines; and judging whether the oscillation alarm circuit alarms mistakenly based on the oscillation early warning proportion. The method is simple in calculation and rapid in judgment, and has relatively high robustness and adaptability.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and more particularly, to a method and system for detecting false alarms of low-frequency oscillations by combining series-parallel relationships. Background Art

[0002] In recent years, with the increasing proportion of power electronic equipment in the power system, the power system oscillation problem has become increasingly complex, and various oscillation events with different manifestations and types have occurred frequently, covering various types of power sources such as hydropower, thermal power, nuclear power, wind farms, and photovoltaic power stations, posing a huge threat to the safe and stable operation of the system. According to the oscillation frequency, there are low-frequency oscillations with oscillation frequencies between 0.1 and 2.5 Hz, ultra-low-frequency oscillations with oscillation frequencies below 0.1 Hz, and in addition, there are broadband oscillations mainly participated in or caused by power electronic equipment, including sub / supersynchronous oscillations with voltage / current frequencies above 3 to 5 Hz but below twice the synchronous frequency, and high-frequency oscillations above twice the synchronous frequency. This report refers to them as full-band oscillations, including ultra-low-frequency oscillations, low-frequency oscillations, and broadband oscillations (including sub / supersynchronous oscillations and high-frequency oscillations).

[0003] There have been some engineering applications for the monitoring and early warning of low-frequency oscillations in traditional power systems. The WAMS system is an important part of the intelligent grid dispatching control system. Compared with SCADA data, WAMS data has the advantages of high density, good synchronization, and containing phase angle information, providing important technical support for power grid operation dynamic monitoring and characteristic analysis at all levels of dispatching agencies. Currently, it mainly has functions such as power grid dynamic monitoring, low-frequency oscillation online monitoring, online disturbance identification, and online monitoring of the grid-connected unit's grid-connected control performance. However, in actual engineering applications, it is found that there are many abnormal situations in WAMS data, especially in aspects such as data acquisition, measurement transmission, and synchronous timekeeping, resulting in difficulties in comprehensively carrying out advanced application analysis based on WAMS data. Due to the large amount of PMU data and many transmission links, there are many PMU data quality problems, which may cause false oscillation alarms. How to determine whether an oscillation alarm is a false alarm is of great significance. Summary of the Invention

[0004] According to the present invention, there is provided a method and system for detecting false alarms of low-frequency oscillations by combining series-parallel relationships to solve the technical problem that in actual engineering applications, it is found that there are many abnormal situations in WAMS data, especially in aspects such as data acquisition, measurement transmission, and synchronous timekeeping, resulting in difficulties in comprehensively carrying out advanced application analysis based on WAMS data. Due to the large amount of PMU data and many transmission links, there are many PMU data quality problems, which may cause false oscillation alarms. How to determine whether an oscillation alarm is a false alarm is of great significance.

[0005] According to the first aspect of the present invention, a method for detecting false alarms of low-frequency oscillations combining series and parallel relationships is provided, including:

[0006] Obtain the real-time operation data of the power grid, and search for the set of lines directly connected to the oscillation alarm line according to the grid connection relationship in the real-time operation data of the power grid;

[0007] Obtain the line operating power and calculate the distribution factors between the lines in the line set, determine the series-parallel relationship between the oscillation alarm line and the connected lines, and incorporate the lines with a series relationship into a series line set;

[0008] Calculate the oscillation amplitude of each line in the series line set, and calculate the oscillation warning ratio based on the number of oscillation warning lines;

[0009] Judge whether the oscillation alarm line is a false alarm based on the oscillation warning ratio.

[0010] Optionally, obtaining the real-time operation data of the power grid, and searching for the set of lines directly connected to the oscillation alarm line according to the grid connection relationship in the real-time operation data of the power grid includes:

[0011] Obtain the real-time operation data of the power grid, and according to the grid connection relationship in the real-time operation data of the power grid, obtain the set of lines directly connected to the head bus or the tail bus of the oscillation alarm line. The line with an oscillation amplitude greater than the set alarm threshold P OSC w is determined as the oscillation alarm line, denoted as line L i ,;

[0012] Obtain the real-time operation data of the power grid, and according to the grid connection relationship in the data, obtain the head bus N i of line L is and the tail bus N ie , search for all lines whose head bus is N is or N ie , or the tail bus is N is or N ie , and incorporate them into the line set Set CNL .

[0013] Optionally, obtaining the line operating power and calculating the distribution factors between the lines in the line set, and determining the series-parallel relationship between the oscillation alarm line and the connected lines, and incorporating the lines with a series relationship into a series line set includes:

[0014] Obtain the operating power P i of line L i , and for the line set Set CNL obtain the operating power of each line L j one by one, denoted as P j, calculate L one by one i and the line set Set CNL the mutual distribution factor D of line j in i-j , D j-i , the calculation formula is:

[0015] D i-j =(X i-j / x i ) / (1 - X j-j / x j )

[0016] D j-i =(X j-i / x j ) / (1 - X i-i / x i )

[0017] where X i-j is the mutual impedance between two nodes i and j, X j-i is the mutual impedance between two nodes j and i, X i-i is the mutual impedance between two nodes i and i, X j-j is the mutual impedance between two nodes j and j, x i is the impedance of line i, x j is the impedance of line j;

[0018] According to the operating power P i of line L i , the operating power P j of each line L j , the mutual distribution factor D i-j , D j-i to judge whether line L i and line L j are in series;

[0019] where the criterion for judging whether line L i and line L j are in series is as follows:

[0020] a) If P j > 0 and P i > 0, D i-j < - 0.1 and D j-i < - 0.1;

[0021] b) If P j < 0 and P i < 0, D i-j < - 0.1 and D j-i < - 0.1;

[0022] c) If P j< 0 and P i > 0, D i-j > 0.1 and D j-i > 0.1;

[0023] d) If P j > 0 and P i < 0, D i-j > 0.1 and D j-i > 0.1;

[0024] Among them, 0.1 is the distribution factor threshold for judging whether the connection relationship between two lines is close. If the absolute value of the distribution factor between two lines is greater than the threshold 0.1, it is considered that the connection is close. If any of the above conditions is met, it is determined that the two lines are in a series relationship;

[0025] Put the line set Set CNL and the lines in the line L i that are in a series relationship into the series line set Set CNL-S .

[0026] Optionally, calculate the oscillation amplitude of each line in the series line set, and calculate the oscillation warning ratio based on the number of oscillation warning lines, including:

[0027] Calculate the oscillation amplitude of each line in the line set Set CNL-S one by one. The line with an oscillation amplitude greater than the set warning threshold P OSC ew is determined as an oscillation warning line;

[0028] Count the number of oscillation warning lines N CNL-S in the line set Set ew , and calculate the warning ratio Perc ew = N ew / N CNL-S , where N CNL-S is the number of lines in the line set Set CNL-S .

[0029] Optionally, judge whether the oscillation warning line is mis-alarmed based on the oscillation warning ratio, including:

[0030] According to the oscillation warning ratio Perc ew , if Perc ew is less than the set threshold 0.3, it is determined that the oscillation warning of the line L i is a mis-alarm.

[0031] According to another aspect of the present invention, there is also provided a low-frequency oscillation mis-alarm detection system combining series and parallel relationships, including:

[0032] A search line set module, which is used to obtain real-time grid operation data, and search for a set of lines directly connected to the oscillation warning line according to the grid connection relationship in the real-time grid operation data;

[0033] An incorporated series line module, which is used to obtain the line operating power and calculate the distribution factor between the lines in the line set, judge the series-parallel relationship between the oscillation warning line and the connected lines, and incorporate the lines with a series relationship to form a series line set;

[0034] A calculation oscillation warning ratio module, which is used to calculate the oscillation amplitude of each line in the series line set and calculate the oscillation warning ratio based on the number of oscillation warning lines;

[0035] A judgment warning module, which is used to judge whether the oscillation warning line is a false warning based on the oscillation warning ratio.

[0036] Optionally, the search line set module includes:

[0037] A determine line sub-module, which is used to obtain real-time grid operation data, and obtain a set of lines directly connected to the head bus or the tail bus of the oscillation warning line according to the grid connection relationship in the real-time grid operation data. The line with an oscillation amplitude greater than the set warning threshold P OSC w is determined as the oscillation warning line, denoted as line L i ,;

[0038] A determine line set sub-module, which is used to obtain real-time grid operation data, and obtain the head bus N i of line L is and the tail bus N ie , search for all lines whose head bus is N is or N ie , or the tail bus is N is or N ie , and incorporate them into the line set Set CNL .

[0039] Optionally, the incorporated series line module includes:

[0040] A calculate distribution factor sub-module, which is used to obtain the operating power P i of line L i , and for each line in the line set Set CNL obtain the operating power of each line L j denoted as P j , and calculate the mutual distribution factor D i between L CNL and line j in the line set Set i-j , D j-i , and the calculation formula is:

[0041] D i-j =(X i-j / x i ) / (1 - X j-j / x j )

[0042] D j-i =(X j-i / x j ) / (1 - X i-i / x i )

[0043] where X i-j is the mutual impedance between two node pairs of nodes i and j, X j-i is the mutual impedance between two node pairs of nodes j and i, X i-i is the mutual impedance between two node pairs of nodes i and i, X j-j is the mutual impedance between two node pairs of nodes j and j, x i is the impedance of line i, x j is the impedance of line j;

[0044] A sub - module for judging series connection, which is used to judge whether line L i and line L i are in series according to the operating power P j of each line L j and the mutual distribution factor D i-j , D j-i ; i and line L j ;

[0045] The criterion for judging whether line L i and line L j are in series is as follows:

[0046] a) If P j > 0 and P i > 0, D i-j < - 0.1 and D j-i < - 0.1;

[0047] b) If P j < 0 and P i < 0, D i-j < - 0.1 and D j-i < - 0.1;

[0048] c) If P j < 0 and P i > 0, D i-j > 0.1 and D j-i > 0.1;

[0049] d) If P j > 0 and P i < 0, D i-j > 0.1 and D j-i > 0.1;

[0050] Among them, 0.1 is the distribution factor threshold for judging whether the connection relationship between two lines is close. If the absolute value of the distribution factor between two lines is greater than the threshold 0.1, it is considered that the connection is close. If any of the above conditions is met, it is determined that the two lines are in series relationship;

[0051] Incorporate the series line sub-module for neutralizing the lines in the line set Set CNL and the line L i that are in series relationship into the series line set Set CNL-S .

[0052] Optionally, the oscillation warning ratio calculation module includes:

[0053] The oscillation warning line determination sub-module is used to calculate the oscillation amplitude of each line in the series line set Set CNL-S one by one. The line with an oscillation amplitude greater than the set warning threshold P OSC ew is determined as an oscillation warning line;

[0054] The warning ratio calculation sub-module is used to count the number N CNL-S of oscillation warning lines in the line set Set ew , and calculate the warning ratio Perc ew = N ew / N CNL-S , where N CNL-S is the number of lines in the line set Set CNL-S .

[0055] Optionally, the alarm judgment module includes:

[0056] The alarm judgment sub-module is used to judge according to the oscillation warning ratio Perc ew . If Perc ew is less than the set threshold 0.3, it is determined that the oscillation alarm of the line L i is a false alarm.

[0057] Thus, the method for determining whether an oscillation alarm is a false alarm by using power grid operation data realizes the determination of whether an oscillation alarm line is a false alarm by judging the series-parallel relationship between the oscillation alarm line and the connected lines, and calculating the oscillation warning ratio of the series lines of the oscillation alarm line. The determination method proposed by the present invention is simple in calculation, rapid in determination, and has high robustness and adaptability. Description of the Drawings

[0058] The exemplary embodiments of the present invention can be more fully understood by referring to the following accompanying drawings:

[0059] Figure 1 It is a schematic flowchart of a method for detecting false alarms of low-frequency oscillations that combines series and parallel relationships according to this embodiment;

[0060] Figure 2 It is a schematic diagram of a system for detecting false alarms of low-frequency oscillations that combines series and parallel relationships according to this embodiment. Detailed Embodiments

[0061] Now, exemplary embodiments of the present invention will be introduced with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely, and to fully convey the scope of the present invention to those skilled in the art. The terms in the exemplary embodiments shown in the accompanying drawings are not limitations on the present invention. In the drawings, the same units / components are denoted by the same reference numerals.

[0062] Unless otherwise specified, the terms (including scientific and technical terms) used herein have the ordinary meaning understood by those skilled in the art. Additionally, it can be understood that terms defined in a commonly used dictionary should be construed as having a meaning consistent with the context of their relevant fields, and should not be construed as having an idealized or overly formal meaning.

[0063] According to the first aspect of the present invention, a method 100 for detecting false alarms of low-frequency oscillations that combines series and parallel relationships is provided. Referring to Figure 1 as shown, the method 100 includes:

[0064] S101: Obtain the real-time operation data of the power grid, and search for the set of lines directly connected to the oscillation alarm line according to the grid topology connection relationship in the real-time operation data of the power grid;

[0065] S102: Obtain the line operating power and calculate the distribution factors between the lines in the line set, determine the series and parallel relationships between the oscillation alarm line and the connected lines, and incorporate the lines with a series relationship into a series line set;

[0066] S103: Calculate the oscillation amplitudes of the individual lines in the series line set, and calculate the oscillation warning ratio based on the number of oscillation warning lines;

[0067] S104: Determine whether the oscillation alarm line is a false alarm based on the oscillation warning ratio.

[0068] Specifically, it includes the following steps:

[0069] 1) Search for the set of lines directly connected to the oscillation alarm line;

[0070] 2) Determine the series and parallel relationships between the oscillation alarm line and the connected lines;

[0071] 3) Calculate the oscillation warning ratio of the series lines of the oscillation alarm line;

[0072] 4) Determine whether the oscillation alarm line is a false alarm.

[0073] Among them, for the set of lines directly connected to the oscillation alarm line in step 1), obtain the real-time operation data of the power grid, and according to the grid connection relationship in the data, obtain the set of lines directly connected to the start bus or end bus of the oscillation alarm line.

[0074] The line with an oscillation amplitude greater than the set alarm threshold P OSC w is determined as the oscillation alarm line, denoted as line L i , obtain the real-time operation data of the power grid, and according to the grid connection relationship in the data, obtain the start bus N i and the end bus N is of line L ie , search for all lines whose start bus is N is or N ie , or the end bus is N is or N ie , and include them in the line set Set CNL .

[0075] Among them, for the step 2) of determining the series and parallel relationships between the oscillation alarm line and the connected lines, read the real-time operation data of the power grid obtained in step 1), obtain the line operating power and calculate the distribution factor between the lines, and determine the series and parallel relationships between the oscillation alarm line and the connected lines.

[0076] Obtain the operating power P i of line L i , for each line in the line set Set CNL obtain the operating power of each line L j denoted as P j , calculate the mutual distribution factor D i between L CNL and line j in the line set Set i-j , D j-i .

[0077] D i-j =(X i-j / x i ) / (1 - X j-j / x j )

[0078] D j-i =(X j-i / x j ) / (1 - X i-i / x i )

[0079] where X i-j is the mutual impedance between two node pairs of nodes i and j, X j-i is the mutual impedance between two node pairs of nodes j and i, X i-i is the mutual impedance between two node pairs of nodes i and i, X j-j is the mutual impedance between two node pairs of nodes j and j, x i is the impedance of line i, x j is the impedance of line j.

[0080] Based on P i , P j , D i-j , D j-i judge whether line L i and line L j are in series.

[0081] A criterion for judging whether line L i and line L j are in series is proposed as follows:

[0082] a) If P j > 0 and P i > 0, D i-j < - 0.1 and D j-i < - 0.1;

[0083] b) If P j < 0 and P i < 0, D i-j < - 0.1 and D j-i < - 0.1;

[0084] c) If P j < 0 and P i > 0, D i-j > 0.1 and D j-i > 0.1;

[0085] d) If P j > 0 and P i < 0, D i-j > 0.1 and D j-i > 0.1;

[0086] where 0.1 is the threshold of the distribution factor for judging whether the connection relationship between two lines is close, that is, if the absolute value of the distribution factor between two lines is greater than the threshold 0.1, it is considered that the connection is close.

[0087] That is, if any of the above conditions is satisfied, it can be determined that the two lines are in a series relationship. The line set Set CNL and the line L i The lines in a series relationship are included in the line set Set CNL-S .

[0088] Among them, in step 3), calculate the oscillation early warning ratio of the series lines of the oscillation warning line, and judge one by one whether the oscillation amplitude of the lines in series with the oscillation warning line reaches the early warning threshold, and count the early warning ratio.

[0089] Calculate one by one the oscillation amplitudes of the lines in the line set Set CNL-S If the oscillation amplitude is greater than the set early warning threshold P OSC ew The line is determined as an oscillation early warning line, and count the number N of oscillation early warning lines in the line set Set CNL-S , calculate the early warning ratio Perc ew , ew =N ew / N CNL-S , N CNL-S is the number of lines in the line set Set CNL-S .

[0090] Among them, in step 4), judge whether the oscillation warning line is a false warning. According to the series line oscillation early warning ratio Perc ew calculated in step 3), if Perc ew is less than the set threshold of 0.3, it is determined that the oscillation warning of line L i is a false warning.

[0091] Therefore, the method for determining whether an oscillation warning is a false warning by using grid operation data realizes the determination of whether an oscillation warning line is a false warning by judging the series-parallel relationship between the oscillation warning line and the connected lines, and calculating the oscillation early warning ratio of the series lines of the oscillation warning line. The determination method proposed by the present invention is simple in calculation, rapid in determination, and has high robustness and adaptability.

[0092] Optionally, obtain the real-time grid operation data, and search for the line set directly connected to the oscillation warning line according to the grid topology connection relationship in the real-time grid operation data, including:[[]]

[0093] Obtain the real-time grid operation data, and obtain the line set directly connected to the head bus or the tail bus of the oscillation warning line according to the grid topology connection relationship in the real-time grid operation data. If the oscillation amplitude is greater than the set warning threshold P OSC w The line is determined as an oscillation warning line, denoted as line L i ,;

[0094] Obtain the real-time operation data of the power grid, and according to the grid connection relationship in the data, obtain line L i The head bus N is and the tail bus N ie , search for all lines whose head bus is N is or N ie , or the lines whose tail bus is N is or N ie , and incorporate them into the formed series line set Set CNL .

[0095] Optionally, obtain the line operating power and calculate the distribution factors between the lines in the line set, determine the series-parallel relationship between the oscillation warning line and the connected lines, and incorporate the series-related lines into the formed series line set, including:

[0096] Obtain the operating power P i of line L i , for the line set Set CNL , obtain the operating power of each line L j one by one and record it as P j , calculate the mutual distribution factor D i between L CNL and line j in the line set Set i-j , D j-i , and the calculation formula is:

[0097] D i-j =(X i-j / x i ) / (1 - X j-j / x j )

[0098] D j-i =(X j-i / x j ) / (1 - X i-i / x i )

[0099] Where X i-j is the mutual impedance between two node pairs of nodes i and j, X j-i is the mutual impedance between two node pairs of nodes j and i, X i-i is the mutual impedance between two node pairs of nodes i and i, X j-j is the mutual impedance between two node pairs of nodes j and j, x i is the impedance of line i, x j is the impedance of line j;

[0100] According to the operating power P i of line L i , each line Lj The operating power P j , the mutual distribution factor D i-j , D j-i Judge whether line L i and line L j are in series;

[0101] Among them, the criterion for judging whether line L i and line L j are in series is as follows:

[0102] a) If P j > 0 and P i > 0, D i-j < -0.1 and D j-i < -0.1;

[0103] b) If P j < 0 and P i < 0, D i-j < -0.1 and D j-i < -0.1;

[0104] c) If P j < 0 and P i > 0, D i-j > 0.1 and D j-i > 0.1;

[0105] d) If P j > 0 and P i < 0, D i-j > 0.1 and D j-i > 0.1;

[0106] Among them, 0.1 is the distribution factor threshold for judging whether the connection relationship between two lines is close. If the absolute value of the mutual distribution factor between two lines is greater than the threshold 0.1, it is considered that the connection is close. If any of the above conditions is met, it is judged that the two lines are in a series relationship;

[0107] Include the lines in the line set Set CNL that are in series with line L i into the series line set Set CNL-S .

[0108] Optionally, calculate the oscillation amplitude of each line in the series line set, and calculate the oscillation warning ratio based on the number of oscillation warning lines, including:

[0109] Calculate the oscillation amplitude of each line in the line set Set CNL-S one by one. The line with an oscillation amplitude greater than the set warning threshold P OSC ew is determined as an oscillation warning line;

[0110] Statistical line set Set CNL-S Number of oscillation warning lines N in ew , calculate the warning ratio Perc based on the number of oscillation warning lines ew = N ew / N CNL-S , where N CNL-S is the number of lines in the line set Set CNL-S .

[0111] Optionally, determine whether the oscillation warning line is a false warning based on the oscillation warning ratio, including:

[0112] According to the oscillation warning ratio Perc ew , if Perc ew is less than the set threshold 0.3, it is determined that the oscillation warning of line L i is a false warning.

[0113] According to another aspect of the present invention, a low-frequency oscillation false warning detection system 200 combining series and parallel relationships is also provided. Referring to Figure 2 shown, the system 200 includes:

[0114] Search line set module 210, which is used to obtain the real-time operation data of the power grid, and search for the line set directly connected to the oscillation warning line according to the grid topology connection relationship in the real-time operation data of the power grid;

[0115] Incorporate series line module 220, which is used to obtain the line operating power and calculate the distribution factor between the lines in the line set, judge the series and parallel relationships between the oscillation warning line and the connected lines, and incorporate the lines with series relationships to form a series line set;

[0116] Calculate oscillation warning ratio module 230, which is used to calculate the oscillation amplitude of each line in the series line set and calculate the oscillation warning ratio based on the number of oscillation warning lines;

[0117] Judge warning module 240, which is used to judge whether the oscillation warning line is a false warning based on the oscillation warning ratio.

[0118] Optionally, the search line set module includes:

[0119] Determine line sub-module, which is used to obtain the real-time operation data of the power grid, obtain the line set directly connected to the head bus or end bus of the oscillation warning line according to the grid topology connection relationship in the real-time operation data of the power grid, and the line with an oscillation amplitude greater than the set warning threshold P OSC w is determined as the oscillation warning line, denoted as line L i ,;

[0120] A line set sub-module, which is used to obtain real-time operation data of the power grid and obtain line L according to the grid connection relationship in the data i The head bus N is and the end bus N ie , search for all lines whose head bus is N is or N ie , or the end bus is N is or N ie , and include the lines in the line set Set CNL .

[0121] Optionally, include a series line module, including:

[0122] A distribution factor calculation sub-module, which is used to obtain the operating power P i of line L i , and for each line in the line set Set CNL , obtain the operating power of each line L j , denoted as P j , and calculate the mutual distribution factor D i between L CNL and line j in the line set Set i-j , D j-i , and the calculation formula is:

[0123] D i-j =(X i-j / x i ) / (1 - X j-j / x j )

[0124] D j-i =(X j-i / x j ) / (1 - X i-i / x i )

[0125] where X i-j is the mutual impedance between two nodes i and j, X j-i is the mutual impedance between two nodes j and i, X i-i is the mutual impedance between two nodes i and i, X j-j is the mutual impedance between two nodes j and j, x i is the impedance of line i, and x j is the impedance of line j;

[0126] A series judgment sub-module, which is used to judge according to the operating power P i of line L i , the operating power P j of each line L j , and the mutual distribution factor Di-j , D j-i Determine whether line L i and line L j are in series;

[0127] Among them, the criterion for determining whether line L i and line L j are in series is as follows:

[0128] a) If P j > 0 and P i > 0, D i-j < - 0.1 and D j-i < - 0.1;

[0129] b) If P j < 0 and P i < 0, D i-j < - 0.1 and D j-i < - 0.1;

[0130] c) If P j < 0 and P i > 0, D i-j > 0.1 and D j-i > 0.1;

[0131] d) If P j > 0 and P i < 0, D i-j > 0.1 and D j-i > 0.1;

[0132] Among them, 0.1 is the distribution factor threshold for judging whether the connection relationship between two lines is close. If the absolute value of the distribution factor between two lines is greater than the threshold 0.1, it is considered that the connection is close. If any of the above conditions is met, it is determined that the two lines are in a series relationship;

[0133] Incorporate into the series line sub - module, which is used to incorporate the lines in the line set Set CNL that are in series with line L i into the series line set Set CNL-S .

[0134] Optionally, the oscillation warning ratio calculation module includes:

[0135] The oscillation warning line determination sub - module, which is used to calculate the oscillation amplitude of each line in the series line set Set CNL-S one by one. The lines with an oscillation amplitude greater than the set warning threshold P OSC ew are determined as oscillation warning lines;

[0136] The warning ratio calculation sub - module, which is used to count the line set Set CNL-SThe number N of oscillation warning lines ew , calculate the warning ratio Perc based on the number N of oscillation warning lines ew = N ew / N CNL-S , where N CNL-S is the number of lines in the line set Set CNL-S .

[0137] Optionally, a judgment warning module includes:

[0138] A judgment warning sub-module is used to, according to the oscillation warning ratio Perc ew , if Perc ew is less than the set threshold 0.3, then determine that the oscillation warning of line L i is a false warning.

[0139] A low-frequency oscillation false warning detection system 200 combining series-parallel relationships in an embodiment of the present invention corresponds to a low-frequency oscillation false warning detection method 100 combining series-parallel relationships in another embodiment of the present invention, which will not be elaborated here.

[0140] Those skilled in the art should understand that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of the present application can be implemented in various computer languages, for example, object-oriented programming languages such as Java and interpreted scripting languages such as JavaScript.

[0141] The present application 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 application. It should be understood that each process and / or block in the flowchart and / or block diagram, and the combination of processes and / or blocks in the flowchart and / or block diagram, can 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 means for implementing the functions specified in one process Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0142] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to work in a particular manner, such that the instructions stored in the computer-readable memory produce a manufacture including an instruction device that implements the functions specified in one or more of the processes Figure 1 or blocks Figure 1 specified in one or more of the processes and / or blocks.

[0143] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus, such that a series of operational steps are performed on the computer or other programmable apparatus to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable apparatus provide steps for implementing the functions specified in one or more of the processes Figure 1 or blocks Figure 1 specified in one or more of the blocks.

[0144] Although the preferred embodiments of the present application have been described, those skilled in the art can make additional changes and modifications once they learn the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications that fall within the scope of the present application.

[0145] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these modifications and variations.

Claims

1. A low-frequency oscillation false alarm detection method combining series-parallel relationship, characterized in that: include: Acquire real-time operation data of the power grid, and search for a set of lines directly connected to the oscillation alarm line according to the power grid extension connection relationship in the real-time operation data of the power grid; Obtain the line operating power and calculate the distribution factor between the lines in the line set, determine the series-parallel relationship between the oscillation alarm line and the connected lines, and include the lines in the series relationship into the series line set; Calculate the oscillation amplitude of each line in the series line set, and calculate the oscillation warning ratio based on the number of oscillation warning lines; It is determined whether the oscillation alarm circuit gives a false alarm based on the oscillation warning ratio.

2. The method according to claim 1, characterized in that Obtain the real-time operation data of the power grid, and search for a set of lines directly connected to the oscillation alarm line according to the power grid extension connection relationship in the real-time operation data of the power grid, including: Obtain the real-time operation data of the power grid, and according to the power grid connection relationship in the real-time operation data of the power grid, obtain the line set directly connected to the head end bus or the end bus of the oscillation alarm line, and the oscillation amplitude is greater than the set alarm threshold P OSC w The line is determined as an oscillation alarm line and is recorded as line L i ,; Obtain real-time grid operation data, and obtain line L according to the grid connection relationship in the data. i First end busbar N is and the terminal busbar N ie , search for all the first-end busbars N is or N ie , or the end bus is N is or N ie The lines are included in the line set Set CNL .

3. The method according to claim 1, characterized in that Obtain the line operating power and calculate the distribution factor between the lines in the line set, determine the series-parallel relationship between the oscillation alarm line and the connected lines, and include the lines in the series relationship into a series line set, including: Get Line L i Operating power P i , for the line set Set CNL Get each line L one by one j The operating power is denoted as P j , calculate L one by one i and line set Set CNL The mutual distribution factor D of line j i-j , D j-i , the calculation formula is: D i-j =(X i-j / x i ) / (1-X j-j / x j ) D j-i =(X j-i / x j ) / (1-X i-i / x i ) Where X i-j is the mutual impedance between two node pairs, i and j, X j-i is the mutual impedance between two node pairs, node j and node i, X i-i is the mutual impedance between two node pairs i and i, X j-j is the mutual impedance between two node pairs, x i is the impedance of line i, x j is the impedance of line j; According to line L i Operating power P i , each line L j Operating power P j , mutual distribution factor D i-j , D j-i Judgment line L i and line L j Whether to connect in series; The judgment line L i and line L j The criteria for whether to connect in series are as follows: a) If P j >0 and P i >0,D i-j <-0.1 and D j-i <-0.1; b) If P j <0 and P i <0,D i-j <-0.1 and D j-i <-0.1; c) If P j <0 and P i >0,D i-j >0.1 and D j-i >0.1; d) If P j >0 and P i <0,D i-j >0.1 and D j-i >0.1; 0.1 is the distribution factor threshold for judging whether the connection between two lines is close. If the absolute value of the distribution factor between two lines is greater than the threshold 0.1, the connection is considered to be close. If any of the above conditions is met, the two lines are judged to be in a series relationship. Set the line CNL Neutral Line L i The lines in series relationship are included in the series line set Set CNL-S .

4. The method according to claim 1, characterized in that Calculate the oscillation amplitude of each line in the series line set, and calculate the oscillation warning ratio based on the number of oscillation warning lines, including: Calculate the line set Set one by one CNL-S The oscillation amplitude of each line in the OSC ew The line is determined as an oscillation warning line; Statistics line set Set CNL-S Number of medium oscillation warning lines N ew , calculate the warning ratio Perc based on the number of oscillation warning lines ew =N ew / N CNL-S , where N CNL-S Is the line set Set CNL-S The number of lines in .

5. The method according to claim 1, characterized in that Judging whether the oscillation alarm circuit has a false alarm based on the oscillation warning ratio includes: According to the oscillation warning ratio Perc ew , if Perc ew If it is less than the set threshold value of 0.3, the line L is determined i The oscillation alarm is a false alarm.

6. A low-frequency oscillation false alarm detection system combining series-parallel relationship, characterized in that: include: A line collection search module is used to obtain real-time grid operation data and search for a line collection directly connected to the oscillation alarm line according to the grid extension connection relationship in the real-time grid operation data; A series line module is included to obtain the line operating power and calculate the distribution factor between the lines in the line set, determine the series-parallel relationship between the oscillation alarm line and the connected lines, and include the lines in the series relationship to form a series line set; An oscillation warning ratio calculation module is used to calculate the oscillation amplitude of each line in the series line set and calculate the oscillation warning ratio based on the number of oscillation warning lines; The alarm judging module is used to judge whether the oscillation alarm circuit has given a false alarm based on the oscillation warning ratio.

7. The system according to claim 6, characterized in that Search line collection module, including: Determine the line submodule, which is used to obtain the real-time operation data of the power grid. According to the power grid connection relationship in the real-time operation data of the power grid, obtain the line set directly connected to the head end bus or the end bus of the oscillation alarm line. The oscillation amplitude is greater than the set alarm threshold P. OSC w The line is determined as an oscillation alarm line and is recorded as line L i ,; Determine the line collection submodule, which is used to obtain real-time grid operation data and obtain line L according to the grid connection relationship in the data. i First end busbar N is and the terminal busbar N ie , search for all the first-end busbars N is or N ie , or the end bus is N is or N ie The lines are included in the line set Set CNL .

8. The system according to claim 6, characterized in that Incorporates serial line modules, including: Calculate the distribution factor submodule to obtain the line L i Operating power P i , for the line set Set CNL Get each line L one by one j The operating power is denoted as P j , calculate L one by one i and line set Set CNL The mutual distribution factor D of line j i-j , D j-i , the calculation formula is: D i-j =(X i-j / x i ) / (1-X j-j / x j ) D j-i =(X j-i / x j ) / (1-X i-i / x i ) Where X i-j is the mutual impedance between two node pairs, i and j, X j-i is the mutual impedance between two node pairs, node j and node i, X i-i is the mutual impedance between two node pairs i and i, X j-j is the mutual impedance between two node pairs, x i is the impedance of line i, x j is the impedance of line j; Determine whether to connect the submodules in series according to the line L i Operating power P i , each line L j Operating power P j , mutual distribution factor D i-j , D j-i Judgment line L i and line L j Whether to connect in series; The judgment line L i and line L j The criteria for whether to connect in series are as follows: a) If P j >0 and P i >0,D i-j <-0.1 and D j-i <-0.1; b) If P j <0 and P i <0,D i-j <-0.1 and D j-i <-0.1; c) If P j <0 and P i >0,D i-j >0.1 and D j-i >0.1; d) If P j >0 and P i <0,D i-j >0.1 and D j-i >0.1; 0.1 is the distribution factor threshold for judging whether the connection between two lines is close. If the absolute value of the distribution factor between two lines is greater than the threshold 0.1, the connection is considered to be close. If any of the above conditions is met, the two lines are judged to be in a series relationship. Included in the series line submodule, used to set the line set Set CNL Neutral Line L i The lines in series relationship are included in the series line set Set CNL-S .

9. The system according to claim 6, characterized in that Calculate the oscillation warning ratio module, including: Determine the oscillation warning line submodule, which is used to calculate the series line set Set one by one CNL-S The oscillation amplitude of each line in the OSC ew The line is determined as an oscillation warning line; Calculate the warning ratio submodule, which is used to count the line set Set CNL-S Number of medium oscillation warning lines N ew , calculate the warning ratio Perc based on the number of oscillation warning lines ew =N ew / N CNL-S , where N CNL-S Is the line set Set CNL-S The number of lines in .

10. The system according to claim 6, characterized in that The judgment alarm module includes: The judgment alarm submodule is used to judge the alarm ratio Perc ew , if Perc ew If it is less than the set threshold value of 0.3, the line L is determined i The oscillation alarm is a false alarm.

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