Auxiliary safety prompting device and method convenient for disconnection and connection of relay protection secondary circuit

Abstract

The invention provides an auxiliary safety prompting device and method convenient for connecting and disconnecting a relay protection secondary circuit, and the method comprises the steps: employing a data collection unit, a data processing unit, a voltage collection line, and a Hall transformer, and preliminarily judging whether the connecting and disconnecting are correct or not according to the gray correlation degree of the magnetic flux changes at a terminal disconnecting part and a to-be-maintained device; and the correctness of connection and disconnection is further judged according to morphological characteristics of voltage sampling. According to the invention, only one set of wireless connection system is needed to collect and calculate the measurement of the secondary circuit connection and disconnection line, two groups of personnel do not need to be arranged at the to-be-overhauled equipment and the connection and disconnection position for measurement and connection and disconnection, and the magnetic flux and voltage curve fitting is used as an auxiliary tool. And the safety, efficiency and quality of secondary circuit wire disconnecting and connecting work can be obviously improved.

Description

Technical Field

[0001] The invention relates to the field of secondary safety of transformer substations, and in particular to an auxiliary safety prompting device and method for facilitating disconnection of a secondary circuit of relay protection. Background Art

[0002] In the work of substation comprehensive transformation, protection inspection, low-frequency and low-voltage device inspection, etc., the correct implementation and restoration of secondary safety measures is a very important task and a prerequisite for ensuring the safe development of secondary work. At present, two groups of personnel are required to implement secondary safety measures at the work site. One group of personnel performs potential measurement work on the side of the device to be repaired, and the other group of personnel performs wiring or wiring restoration work at the panel cabinet where the operating device is located, and they need to bring appropriate communication equipment. On the one hand, this work requires a lot of manpower, and on the other hand, it is restricted by the communication signal in the substation. Sometimes the call quality is not good, which has a certain impact on the on-site work. Summary of the invention

[0003] The purpose of the present invention is to provide an auxiliary safety prompt device and method for facilitating disconnection of a relay protection secondary circuit. On the one hand, the device can quickly predict potential safety hazards through changes in the magnetic field, and on the other hand, the device can accurately determine the accuracy of disconnection through voltage.

[0004] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0005] Auxiliary safety reminder device for facilitating disconnection of relay protection secondary circuit, including:

[0006] The data acquisition unit is installed at the maintenance equipment and is used to collect the voltage and magnetic flux changes at each terminal of the terminal block;

[0007] The data processing unit is in communication connection with the data acquisition unit, and is used to collect the terminal voltage and magnetic flux at the disconnection wire, and process the voltage information and magnetic flux change information;

[0008] The voltage collection line is connected between the data collection unit and the terminal block, and between the data processing unit and the terminal at the disconnection point, and is used to collect voltage;

[0009] The Hall transformer is set at the voltage input line interface to collect magnetic flux change information.

[0010] Furthermore, the voltage collection line is connected to the conductive disassembly device for real-time collection of the terminal voltage at the point where the wire is removed.

[0011] An auxiliary safety reminder method for facilitating disconnection of a relay protection secondary circuit includes the following steps:

[0012] S1. Preliminary judgment based on the change in magnetic flux that the wiring is correct:

[0013] S101. Collect the change of magnetic flux at the terminal disconnection point and record it as a parent sequence;

[0014] S102. Collect the magnetic flux change of the terminal channel of the equipment to be repaired, and record it as a subsequence;

[0015] S103. Calculate the grey correlation between the subsequence and the parent sequence to determine whether the cable numbers on both sides correspond;

[0016] S2. Further determine the correctness of disconnection and wiring based on voltage sampling:

[0017] S201. Collect the voltage waveform at the terminal disconnection point and record it as the voltage reference time series;

[0018] S202. Collect the voltage waveform of the channel selected by grey correlation judgment and record it as a sampling time series;

[0019] S203. Fit the voltage reference time series and the sampling time series respectively, compare the morphological characteristics of the fitted curves, and determine whether the disconnection wiring is correct.

[0020] Furthermore, the calculation steps of grey relational degree include:

[0021] Preprocess the elements of the parent sequence and the child sequence, find the average value of the elements of each sequence, and then divide each element in the sequence by the mean of the sequence to form a standardized matrix;

[0022] Calculate the grey correlation coefficient and grey correlation degree between the subsequence and the parent sequence;

[0023] The terminal with the closest correlation is at the point with the maximum gray correlation.

[0024] Furthermore, the parent sequence is recorded as X′=(x0(0), x0(1), ..., x0(n)), and the subsequence of the t-th acquisition channel is recorded as X t =(x t (0), x t (1),......,x t (n)), n is the number of samples;

[0025] The standardized matrix is ​​denoted as in

[0026] The grey correlation coefficient is:

[0027]

[0028] r is the resolution coefficient, and the grey relational degree is:

[0029] Furthermore, the parameters for morphological feature comparison include:

[0030] Calculate the ratio of the reference voltage value and the sampling voltage value at each moment to see whether the amplitude condition is met;

[0031] When the amplitude condition is met, the difference of the slope at the sampling moment and the second-order derivative are calculated to see whether they have the same sign, and whether the slope condition is met. If so, it is recorded as a matching point;

[0032] Calculate the number of matching points in the sampling sequence Γ t , Γ set is the matching threshold set in advance, if Γ t ≥Γ set , then it means that the disconnected secondary line is correct, otherwise the disconnection conditions are not met.

[0033] Furthermore, the calculation method of the amplitude condition includes the steps of:

[0034] The voltage reference time series is recorded as U′=(u1,u2,......,u p ), the sampling time series of channel t is recorded as U t =(u t1 ,u t2 ,......,u tp ), p is the number of samples;

[0035] Calculate the ratio of two points of the sequence element at the i-th moment δ ti =U ti U i , i = 1, 2, ..., p, if the amplitude parameter δ ti The number in the interval (1-μ, 1+μ) is greater than the specified number, that is, Π t ≥Π set , then the amplitude condition is satisfied and μ is the standard error.

[0036] Furthermore, the calculation method of the slope condition includes the steps of:

[0037] The slope of the reference voltage value corresponding to the i-th moment is recorded as The slope of the sampled voltage value of channel t is recorded as Pick Where i = 1, 2, ..., p, and the curve slope difference threshold is specified as ζ set ;

[0038] The second-order derivative of the reference voltage value corresponding to the i-th moment is recorded as The second-order derivative of the sampled voltage value of channel t is denoted as

[0039] Calculate the first-order derivative and second-order derivative of the reference voltage value and the sampling voltage value, and compare their second-order derivatives. If the second-order derivatives have the same sign, then the two points meet the requirements;

[0040] If the second-order derivatives have different signs, compare the absolute value of the slope difference between the two points. If |ζ ti |≤ζ set , then the two points meet the requirements.

[0041] The invention has the advantage that the magnetic flux and voltage curve fitting are used as auxiliary tools, which can significantly improve the safety, efficiency and quality of secondary circuit disconnection work.

[0042] The present invention only needs one set of wirelessly connected systems to collect and calculate the measurement of secondary circuit disconnection and wiring. It is not necessary to set up two groups of personnel at the equipment to be repaired and the disconnection site to perform measurement and disconnection respectively, which reduces a large amount of human resources and avoids the safety risks caused by coordination errors.

[0043] The present invention proposes to quickly and preliminarily determine whether the disconnection wiring is correct by calculating the grey correlation degree of the magnetic flux change. The change of the magnetic field is often closely related to the current. This change is very rapid and can be captured. Therefore, this solution can assess the risk at the first time and ensure that the work is carried out in a safe situation.

[0044] In addition, as a safeguard, this solution also adds the matching degree of the voltage curve to further confirm the matching method of the terminal blocks. By comparing the ratio, slope and second-order derivative one by one, the matching degree of the fitting curve can be accurately digitized, thereby detecting errors more accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a schematic diagram of the structure of the auxiliary safety prompt device for facilitating disconnection of the secondary circuit of the relay protection according to the present invention;

[0046] Figure 2 This is a structural schematic diagram of a data acquisition unit of the present invention;

[0047] Figure 3 This is a schematic diagram of the connection relationship between the data processing unit and the voltage acquisition line of the present invention;

[0048] Figure 4 This is a schematic diagram of the structure of the data processing unit of the present invention;

[0049] Figure 5 The present invention is a flow chart of the auxiliary safety prompt method for facilitating disconnection of a secondary circuit of a relay protection. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0051] Example 1

[0052] This embodiment discloses an auxiliary safety prompt method for facilitating the disconnection of the secondary circuit of relay protection. Figure 5 , including two steps: speed judgment and accuracy judgment.

[0053] The rapidity judgment is based on the change of magnetic flux, and the preliminary judgment of whether the wiring is correct is made. According to the theory of electromagnetic field, the changing electric field can generate the magnetic field. When the terminal block is disconnected, there are voltage changes at the equipment to be repaired and the disconnected wires, and the corresponding changes in the magnetic field can be felt. By comparing the gray correlation of the magnetic field changes on both sides, the correctness of the disconnection line can be quickly predicted, and the occurrence of wrong disconnection can be prevented in advance; the magnetic field at the adjacent terminals may also be affected. Considering the changes in the magnetic field at all the terminals to be disconnected, the correctness of the wiring can be checked.

[0054] Specifically:

[0055] S1. The voltage waveform at the terminal disconnection point is recorded as U′, and the sequence of magnetic flux changes collected by the Hall sensor is taken as the mother sequence, recorded as X′=(x0(0), x0(1), ..., x0(n)).

[0056] S2. Collect the magnetic flux changes of the terminal channel of the equipment to be repaired and record them as subsequences. For example, the subsequence of the tth channel is recorded as X t =(x t (0), x t (1),......,x t (n)), t = 1, 2, ..., m, m is the total number of channels, and n is the number of samples.

[0057] S3. Preprocess the elements of the parent sequence and the child sequence, find the average value of the elements of each sequence, and then divide each element in the sequence by the mean of the sequence to form a standardized matrix:

[0058]

[0059] in,

[0060] S4. Calculate the grey correlation coefficient between the subsequence and the parent sequence:

[0061]

[0062] The resolution coefficient r is 0.5, and the grey relational degree is:

[0063]

[0064] S5. Calculate the gray correlation of all terminals in the equipment to be repaired. The terminal with the largest gray correlation is the terminal with the closest correlation. Automatically and quickly check whether the cable numbers on both sides correspond. If they do not correspond, an alarm message will be issued to prompt the maintenance personnel to stop disconnecting the wires.

[0065] The accuracy judgment is to use the morphological characteristics of the DC voltage curve to further judge the correctness of the disconnection. Since there are many energized equipment in the substation and there are interfering magnetic fields in the station, in order to further accurately judge the correctness of the disconnection, the morphological characteristics of the voltage curves on both sides are considered to be compared.

[0066] Specifically:

[0067] S6. Collect the voltage waveform at the terminal disconnection point as the voltage reference time series and record it as U′=(u1,u2,......,u p ).

[0068] S7. Collect the voltage waveform at the channel selected by grey correlation judgment and record it as the sampling time series. The sampling time series of channel t is U t =(u t1 ,u t2 ,......,u tp ), p is the number of samples.

[0069] S8. Fit the voltage reference time series and the sampling time series respectively, and compare the morphological characteristics of the fitted curves. The parameters for the morphological characteristic comparison include amplitude parameters and slope difference parameters.

[0070] S9. Calculate the ratio δ of two points of the sequence element at the i-th moment ti =U ti U i , i = 1, 2, ..., p, if the amplitude parameter δ ti The number in the interval (1-μ, 1+μ) is greater than the specified number, that is, Π t ≥Π set , then the amplitude condition is met, μ is the standard error, and its value is 0.1.

[0071] S10. When the amplitude condition is met, the slope of the reference voltage value corresponding to the i-th moment is recorded as The slope of the sampled voltage value of channel t is recorded as Pick Where i = 1, 2, ..., p, and the curve slope difference threshold is specified as ζ set ;

[0072] The second-order derivative of the reference voltage value corresponding to the i-th moment is recorded as The second-order derivative of the sampled voltage value of channel t is denoted as

[0073] Calculate the first-order derivative and second-order derivative of the reference voltage value and the sampling voltage value, and compare their second-order derivatives. If the second-order derivatives have the same sign, then the two points meet the requirements;

[0074] If the second-order derivatives have different signs, compare the absolute value of the slope difference between the two points. If |ζ ti |≤ζ set , then the two points meet the requirements.

[0075] S11. Calculate the number of that meets the requirements in the sampling sequence. If , then it means that the disconnected secondary line is correct, otherwise the disconnection condition is not met.

[0076] Example 2

[0077] This embodiment proposes a device that can implement the security prompt method described in embodiment 1. Figure 1 .

[0078] The invention discloses an auxiliary safety prompt device for facilitating disconnection of a relay protection secondary circuit, comprising a data acquisition unit, a data processing unit, a voltage acquisition line and a Hall transformer.

[0079] The data acquisition unit is installed at the maintenance equipment to collect the voltage and magnetic flux changes at each terminal of the terminal block. It contains a wireless transmission unit. Please refer to Figure 2 .

[0080] The data processing unit is connected to the data acquisition unit for collecting the terminal voltage and magnetic flux at the disconnection point, and processing the voltage information and magnetic flux change information. It also contains a wireless receiving unit. Please refer to Figure 4 , information data can be transmitted between the data acquisition unit and the data processing unit through wireless transmission.

[0081] The voltage collection line is connected between the data collection unit and the terminal block, and between the data processing unit and a disassembly device (such as a screwdriver) at the disassembly line, and is used to collect voltage.

[0082] The Hall transformer is set at the voltage input line interface to collect magnetic flux change information.

[0083] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An auxiliary safety reminder device that facilitates disconnection of the secondary circuit of relay protection, characterized in that: include: The data acquisition unit is installed at the maintenance equipment and is used to collect the voltage and magnetic flux changes at each terminal of the terminal block; The data processing unit is in communication connection with the data acquisition unit, and is used to collect the terminal voltage and magnetic flux at the disconnection wire, and process the voltage information and magnetic flux change information; The voltage collection line is connected between the data collection unit and the terminal block, and between the data processing unit and the terminal at the disconnection point, and is used to collect voltage; The Hall transformer is set at the voltage input line interface to collect magnetic flux change information.

2. The auxiliary safety prompt device for facilitating disconnection of the secondary circuit of relay protection according to claim 1 is characterized in that: The voltage collection line is connected to the conductive disassembly device and is used to collect the terminal voltage at the point where the wire is removed in real time.

3. An auxiliary safety reminder method for facilitating disconnection of a relay protection secondary circuit, characterized in that: Includes steps: S1. Preliminary judgment based on the change in magnetic flux that the wiring is correct: S101. Collect the change of magnetic flux at the terminal disconnection point and record it as a parent sequence; S102. Collect the magnetic flux change of the terminal channel of the equipment to be repaired, and record it as a subsequence; S103. Calculate the grey correlation between the subsequence and the parent sequence to determine whether the cable numbers on both sides correspond; S2. Further determine the correctness of disconnection and wiring based on voltage sampling: S201. Collect the voltage waveform at the terminal disconnection point and record it as the voltage reference time series; S202. Collect the voltage waveform of the channel selected by grey correlation judgment and record it as a sampling time series; S203. Fit the voltage reference time series and the sampling time series respectively, compare the morphological characteristics of the fitted curves, and determine whether the disconnection wiring is correct.

4. The auxiliary safety prompt method for facilitating disconnection of a relay protection secondary circuit according to claim 3 is characterized in that: The calculation steps of the grey relational degree include: Preprocess the elements of the parent sequence and the child sequence, find the average value of the elements of each sequence, and then divide each element in the sequence by the mean of the sequence to form a standardized matrix; Calculate the grey correlation coefficient and grey correlation degree between the subsequence and the parent sequence; The terminal with the closest correlation is at the point with the maximum gray correlation.

5. The auxiliary safety prompt method for facilitating disconnection of a secondary circuit of relay protection according to claim 4, characterized in that: The parent sequence is recorded as X′=(x0(0), x0(1), ..., x0(n)), and the subsequence of the t-th acquisition channel is recorded as X t =(x t (0), x t (1),......,x t (n)), n is the number of samples; The standardized matrix is ​​denoted as in The grey correlation coefficient is: r is the resolution coefficient, and the grey relational degree is:

6. The auxiliary safety prompt method for facilitating disconnection of a relay protection secondary circuit according to claim 3, characterized in that: The parameters for morphological feature comparison include: Calculate the ratio of the reference voltage value and the sampling voltage value at each moment to see whether the amplitude condition is met; When the amplitude condition is met, the difference of the slope at the sampling moment and the second-order derivative are calculated to see whether they have the same sign, and whether the slope condition is met. If so, it is recorded as a matching point; Calculate the number of matching points in the sampling sequence Γ t , Γ set is the matching threshold set in advance, if Γ t ≥Γ set , then it means that the disconnected secondary line is correct, otherwise the disconnection conditions are not met.

7. The auxiliary safety prompt method for facilitating disconnection of a relay protection secondary circuit according to claim 6, characterized in that: The calculation method of the amplitude condition comprises the steps of: The voltage reference time series is recorded as U′=(u1,u2,......,u p ), the sampling time series of channel t is recorded as U t =(u t1 ,u t2 ,......,u tp ), p is the number of samples; Calculate the ratio of two points of the sequence element at the i-th moment δ ti =U ti U i , i = 1, 2, ..., p, if the amplitude parameter δ ti The number in the interval (1-μ, 1+μ) is greater than the specified number, that is, Π t ≥Π set , then the amplitude condition is satisfied and μ is the standard error.

8. The auxiliary safety prompt method for facilitating disconnection of a relay protection secondary circuit according to claim 7, characterized in that: The calculation method of the slope condition comprises the steps of: The slope of the reference voltage value corresponding to the i-th moment is recorded as The slope of the sampled voltage value of channel t is recorded as Pick Where i = 1, 2, ..., p, and the curve slope difference threshold is specified as ζ set ; The second-order derivative of the reference voltage value corresponding to the i-th moment is recorded as The second-order derivative of the sampled voltage value of channel t is denoted as Calculate the first-order derivative and second-order derivative of the reference voltage value and the sampling voltage value, and compare their second-order derivatives. If the second-order derivatives have the same sign, then the two points meet the requirements; If the second-order derivatives have different signs, compare the absolute value of the slope difference between the two points. If |ζ ti |≤ζ set , then the two points meet the requirements.

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