CN111780868A - Transformer running state vibration and noise detection method and system by utilizing Jeffery difference - Google Patents

Transformer running state vibration and noise detection method and system by utilizing Jeffery difference Download PDF

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Publication number
CN111780868A
CN111780868A CN202010666126.8A CN202010666126A CN111780868A CN 111780868 A CN111780868 A CN 111780868A CN 202010666126 A CN202010666126 A CN 202010666126A CN 111780868 A CN111780868 A CN 111780868A
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sequence
signal
difference
jeffery
nth
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翟明岳
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Guangdong University of Petrochemical Technology
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Guangdong University of Petrochemical Technology
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
    • G01H17/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves, not provided for in the preceding groups

Abstract

The embodiment of the invention discloses a method and a system for detecting vibration and sound of a running state of a transformer by utilizing Jeffery difference, wherein the method comprises the following steps: step 101, acquiring a signal sequence S acquired according to a time sequence; step 102, generating a signal first-order difference sequence; step 103, solving a second order difference sequence of the signals; 104, calculating a DFT transformation coefficient; step 105, obtaining a normalized DFT coefficient; step 106, calculating a center frequency; step 107, calculating Jeffery difference; step 108, obtaining a state judgment threshold value; step 109 judges the running state of the transformer.

Description

Transformer running state vibration and noise detection method and system by utilizing Jeffery difference
Technical Field
The invention relates to the field of electric power, in particular to a method and a system for detecting vibration and sound of a transformer in an operation state.
Background
With the high-speed development of the smart grid, the safe and stable operation of the power equipment is particularly important. At present, the detection of the operating state of the power equipment with ultrahigh voltage and above voltage grades, especially the detection of the abnormal state, is increasingly important and urgent. As an important component of an electric power system, a power transformer is one of the most important electrical devices in a substation, and its reliable operation is related to the safety of a power grid.
The basic principle of the transformer operation state detection is to extract each characteristic quantity in the transformer operation, analyze, identify and track the characteristic quantity so as to monitor the abnormal operation state of the transformer. The current common detection methods for the operation state of the transformer include a pulse current method and an ultrasonic detection method for detecting partial discharge, a frequency response method for detecting winding deformation, a vibration detection method for detecting mechanical and electrical faults, and the like. The detection methods mainly detect the insulation condition and the mechanical structure condition of the transformer, wherein the detection of the vibration signal (vibration sound) of the transformer is the most comprehensive, and the fault and the abnormal state of most transformers can be reflected.
Although the transformer vibration and sound detection method is widely applied to monitoring the running state of the transformer and the technology is relatively mature, the vibration and sound detection method utilizes the vibration signal sent by the transformer and is easily influenced by the environmental noise, so that the method often cannot obtain satisfactory results when being applied in the actual working environment.
Disclosure of Invention
As mentioned above, the transformer vibration and noise detection method is widely applied to monitoring the operation state of the transformer, and the technology is relatively mature, but because the vibration and noise detection method utilizes the vibration signal emitted by the transformer, the vibration and noise detection method is easily affected by the environmental noise, and therefore, the method often fails to obtain satisfactory results when being applied in the actual working environment.
The invention aims to provide a method and a system for detecting vibration and sound of a transformer operating state by utilizing Jeffery difference. The method has better robustness and simpler calculation.
In order to achieve the purpose, the invention provides the following scheme:
a method for detecting vibration and noise of a running state of a transformer by utilizing Jeffery difference comprises the following steps:
step 101, acquiring a signal sequence S acquired according to a time sequence;
step 102 generates a first order difference sequence of signals, specifically: the nth signal first order difference sequence is recorded as
Figure BDA0002580526450000011
The 1 st element is 0 and the ith element is
Figure BDA0002580526450000012
Wherein, N is a sequence number and has a value range of N ═ 1,2, ·, N; n is the length of the signal sequence S; siFor the i-th element of the signal sequence S,
Figure BDA0002580526450000013
is the | i-1| > of the signal sequence SNThe element, i is the element serial number, and the value range is i ═ 1,2, ·, n; (| ventilation)NRepresenting the remainder operation modulo N;
step 103, calculating a second order difference sequence of the signal, specifically: the nth signal second order difference sequence is recorded as
Figure BDA0002580526450000014
The 1 st element is 0; the ith element is
Figure BDA0002580526450000015
Wherein the content of the first and second substances,
Figure BDA0002580526450000016
is the | i-2 |' of the signal sequence SNThe number of the elements is one,
step 104, calculating a DFT transform coefficient, specifically: the nth signal first order difference sequence
Figure BDA0002580526450000021
DFT transform coefficient of F1(m1) The formula is
Figure BDA0002580526450000022
The nth second order difference sequence of the signal
Figure BDA0002580526450000023
DFT transform coefficient of F2(m2) (ii) a It is obtained by the formula
Figure BDA0002580526450000024
Wherein m is1For the first order difference sequence of the signal
Figure BDA0002580526450000025
The value range of the DFT transform coefficient sequence number of (1) is m1＝1,2,···,N；m2For the second order difference sequence of the signal
Figure BDA0002580526450000026
The value range of the DFT transform coefficient sequence number of (1) is m2＝1,2,···,N；
Step 105, obtaining a normalized DFT coefficient, specifically: the signal first order difference sequence
Figure BDA0002580526450000027
Normalized DFT coefficient of P1(m1) The calculation formula is
Figure BDA0002580526450000028
The second order difference sequence of the signal
Figure BDA0002580526450000029
Normalized DFT coefficient of P2(m2) The calculation formula is
Figure BDA00025805264500000210
Figure BDA00025805264500000211
Step 106, calculating a center frequency, specifically: the signal first order difference sequence
Figure BDA00025805264500000212
Has a center frequency of
Figure BDA00025805264500000213
The calculation formula is
Figure BDA00025805264500000214
The second order difference sequence of the signal
Figure BDA00025805264500000215
Has a center frequency of
Figure BDA00025805264500000216
The calculation formula is
Figure BDA00025805264500000217
Δ f isThe sampling frequency of the signal sequence S;
step 107, calculating Jeffery difference, specifically: the nth Jeffery difference is recorded as HnThe calculation formula is
Figure BDA00025805264500000218
Wherein D isJIs a Jeffery difference factor and is calculated by the formula
Figure BDA00025805264500000219
m is a summation parameter;
step 108, obtaining a state judgment threshold, specifically: the state judgment threshold is recorded as0The calculation formula is
Figure BDA00025805264500000220
Figure BDA00025805264500000221
Wherein k is a summation parameter; hkIs the k-th Jeffery difference amount;
step 109, judging the running state of the transformer, specifically: judging the nth Jeffery difference HnWhether or not it is greater than or equal to the state judgment threshold value0(ii) a If the nth Jeffery difference HnGreater than or equal to the state judgment threshold value0If so, at the nth point of the signal sequence S, the transformer is in an abnormal operation state; if the nth Jeffery difference HnLess than the state judgment threshold0Then at the nth point of the signal sequence S the transformer is in a normal operating state.
A transformer operation state vibration and noise detection system utilizing Jeffery difference comprises:
the module 201 acquires a signal sequence S acquired in time sequence;
the module 202 generates a first order difference sequence of signals, specifically: the nth signal first order difference sequence is recorded as
Figure BDA00025805264500000222
The 1 st element thereof is 0,the ith element is
Figure BDA00025805264500000223
Wherein, N is a sequence number and has a value range of N ═ 1,2, ·, N; n is the length of the signal sequence S; siFor the i-th element of the signal sequence S,
Figure BDA00025805264500000224
is the | i-1| > of the signal sequence SNThe element, i is the element serial number, and the value range is i ═ 1,2, ·, n; (| ventilation)NRepresenting the remainder operation modulo N;
the module 203 calculates a second order difference sequence of the signal, specifically: the nth signal second order difference sequence is recorded as
Figure BDA0002580526450000031
The 1 st element is 0; the ith element is
Figure BDA0002580526450000032
Wherein the content of the first and second substances,
Figure BDA0002580526450000033
is the | i-2 |' of the signal sequence SNThe number of the elements is one,
the module 204 calculates DFT transform coefficients, specifically: the nth signal first order difference sequence
Figure BDA0002580526450000034
DFT transform coefficient of F1(m1) The formula is
Figure BDA0002580526450000035
The nth second order difference sequence of the signal
Figure BDA0002580526450000036
DFT transform coefficient of F2(m2) (ii) a It is obtained by the formula
Figure BDA0002580526450000037
Wherein m is1For the first order difference sequence of the signal
Figure BDA0002580526450000038
The value range of the DFT transform coefficient sequence number of (1) is m1＝1,2,···,N；m2For the second order difference sequence of the signal
Figure BDA0002580526450000039
The value range of the DFT transform coefficient sequence number of (1) is m2＝1,2,···,N；
The module 205 finds the normalized DFT coefficients, specifically: the signal first order difference sequence
Figure BDA00025805264500000310
Normalized DFT coefficient of P1(m1) The calculation formula is
Figure BDA00025805264500000311
The second order difference sequence of the signal
Figure BDA00025805264500000312
Normalized DFT coefficient of P2(m2) The calculation formula is
Figure BDA00025805264500000313
Figure BDA00025805264500000314
The module 206 calculates a center frequency, specifically: the signal first order difference sequence
Figure BDA00025805264500000315
Has a center frequency of
Figure BDA00025805264500000316
The calculation formula is
Figure BDA00025805264500000317
The second order difference sequence of the signal
Figure BDA00025805264500000318
Has a center frequency of
Figure BDA00025805264500000319
The calculation formula is
Figure BDA00025805264500000320
Δ f is the sampling frequency of the signal sequence S;
the module 207 calculates Jeffery difference, specifically: the nth Jeffery difference is recorded as HnThe calculation formula is
Figure BDA00025805264500000321
Wherein D isJIs a Jeffery difference factor and is calculated by the formula
Figure BDA00025805264500000322
m is a summation parameter;
the module 208 calculates a state determination threshold, specifically: the state judgment threshold is recorded as0The calculation formula is
Figure BDA00025805264500000323
Figure BDA00025805264500000324
Wherein k is a summation parameter; hkIs the k-th Jeffery difference amount;
the module 209 determines the running state of the transformer, specifically: judging the nth Jeffery difference HnWhether or not it is greater than or equal to the state judgment threshold value0(ii) a If the nth Jeffery difference HnGreater than or equal to the state judgment threshold value0If so, at the nth point of the signal sequence S, the transformer is in an abnormal operation state; if the nth Jeffery difference HnLess than the state judgment threshold0Then at the nth point of the signal sequence S the transformer is in a normal operating state.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects:
as mentioned above, the transformer vibration and noise detection method is widely applied to monitoring the operation state of the transformer, and the technology is relatively mature, but because the vibration and noise detection method utilizes the vibration signal emitted by the transformer, the vibration and noise detection method is easily affected by the environmental noise, and therefore, the method often fails to obtain satisfactory results when being applied in the actual working environment.
The invention aims to provide a method and a system for detecting vibration and sound of a transformer operating state by utilizing Jeffery difference. The method has better robustness and simpler calculation.
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In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.
FIG. 1 is a schematic flow diagram of the process of the present invention;
FIG. 2 is a schematic flow chart of the system of the present invention;
FIG. 3 is a flow chart illustrating an embodiment of the present invention.
Detailed Description
The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
FIG. 1 is a schematic flow chart of a transformer operation state vibration and noise detection method using Jeffery difference
Fig. 1 is a schematic flow chart of a method for detecting vibration and noise in a transformer operating state by using Jeffery difference according to the present invention. As shown in fig. 1, the method for detecting the ringing sound in the operating state of the transformer by using the Jeffery difference specifically includes the following steps:
step 101, acquiring a signal sequence S acquired according to a time sequence;
step 102 generates a first order difference sequence of signals, specifically: the nth signal first order difference sequence is recorded as
Figure BDA0002580526450000041
The 1 st element is 0 and the ith element is
Figure BDA0002580526450000042
Wherein, N is a sequence number and has a value range of N ═ 1,2, ·, N; n is the length of the signal sequence S; siFor the i-th element of the signal sequence S,
Figure BDA0002580526450000043
is the | i-1| > of the signal sequence SNThe element, i is the element serial number, and the value range is i ═ 1,2, ·, n; (| ventilation)NRepresenting the remainder operation modulo N;
step 103, calculating a second order difference sequence of the signal, specifically: the nth signal second order difference sequence is recorded as
Figure BDA0002580526450000044
The 1 st element is 0; the ith element is
Figure BDA0002580526450000045
Wherein the content of the first and second substances,
Figure BDA0002580526450000046
is the | i-2 |' of the signal sequence SNThe number of the elements is one,
step 104, calculating a DFT transform coefficient, specifically: the nth signal first order difference sequence
Figure BDA0002580526450000047
DFT transform coefficient of F1(m1) The formula is
Figure BDA0002580526450000048
The nth second order difference sequence of the signal
Figure BDA0002580526450000049
DFT transform coefficient of F2(m2) (ii) a It is obtained by the formula
Figure BDA00025805264500000410
Wherein m is1For the first order difference sequence of the signal
Figure BDA00025805264500000411
The value range of the DFT transform coefficient sequence number of (1) is m1＝1,2,···,N；m2For the second order difference sequence of the signal
Figure BDA00025805264500000412
The value range of the DFT transform coefficient sequence number of (1) is m2＝1,2,···,N；
Step 105, obtaining a normalized DFT coefficient, specifically: the signal first order difference sequence
Figure BDA0002580526450000051
Normalized DFT coefficient of P1(m1) The calculation formula is
Figure BDA0002580526450000052
The second order difference sequence of the signal
Figure BDA0002580526450000053
Normalized DFT coefficient of P2(m2) The calculation formula is
Figure BDA0002580526450000054
Figure BDA0002580526450000055
Step 106, calculating a center frequency, specifically: the signal first order difference sequence
Figure BDA0002580526450000056
Has a center frequency of
Figure BDA0002580526450000057
The calculation formula is
Figure BDA0002580526450000058
The second order difference sequence of the signal
Figure BDA0002580526450000059
Has a center frequency of
Figure BDA00025805264500000510
The calculation formula is
Figure BDA00025805264500000511
Δ f is the sampling frequency of the signal sequence S;
step 107, calculating Jeffery difference, specifically: the nth Jeffery difference is recorded as HnThe calculation formula is
Figure BDA00025805264500000512
Wherein D isJIs a Jeffery difference factor and is calculated by the formula
Figure BDA00025805264500000513
m is a summation parameter;
step 108, obtaining a state judgment threshold, specifically: the state judgment threshold is recorded as0The calculation formula is
Figure BDA00025805264500000514
Figure BDA00025805264500000515
Wherein k is a summation parameter; hkIs the k-th Jeffery difference amount;
step 109, judging the running state of the transformer, specifically: judging the nth Jeffery difference HnWhether or not it is greater than or equal to the state judgment threshold value0(ii) a If the nth Jeffery difference HnGreater than or equal to the state judgment threshold value0If so, at the nth point of the signal sequence S, the transformer is in an abnormal operation state; if the nth Jeffery difference HnLess than the state judgment threshold0Then at the nth point of the signal sequence S the transformer is in a normal operating state.
FIG. 2 is a structural intention of a transformer operation state vibration and noise detection system utilizing Jeffery difference
Fig. 2 is a schematic structural diagram of a transformer operation state vibration and noise detection system using Jeffery difference according to the present invention. As shown in fig. 2, the system for detecting the vibration and noise of the operating state of the transformer by using the Jeffery difference comprises the following structures:
the module 201 acquires a signal sequence S acquired in time sequence;
the module 202 generates a first order difference sequence of signals, specifically: the nth signal first order difference sequence is recorded as
Figure BDA00025805264500000516
The 1 st element is 0 and the ith element is
Figure BDA00025805264500000517
Wherein, N is a sequence number and has a value range of N ═ 1,2, ·, N; n is the length of the signal sequence S; siFor the i-th element of the signal sequence S,
Figure BDA00025805264500000518
is the | i-1| > of the signal sequence SNEach element, i is the element number and the value range isi＝1,2,···,n；||NRepresenting the remainder operation modulo N;
the module 203 calculates a second order difference sequence of the signal, specifically: the nth signal second order difference sequence is recorded as
Figure BDA00025805264500000519
The 1 st element is 0; the ith element is
Figure BDA00025805264500000520
Wherein the content of the first and second substances,
Figure BDA00025805264500000521
is the | i-2 |' of the signal sequence SNThe number of the elements is one,
the module 204 calculates DFT transform coefficients, specifically: the nth signal first order difference sequence
Figure BDA0002580526450000061
DFT transform coefficient of F1(m1) The formula is
Figure BDA0002580526450000062
The nth second order difference sequence of the signal
Figure BDA0002580526450000063
DFT transform coefficient of F2(m2) (ii) a It is obtained by the formula
Figure BDA0002580526450000064
Wherein m is1For the first order difference sequence of the signal
Figure BDA0002580526450000065
The value range of the DFT transform coefficient sequence number of (1) is m1＝1,2,···,N；m2For the second order difference sequence of the signal
Figure BDA0002580526450000066
The value range of the DFT transform coefficient sequence number of (1) is m2＝1,2,···,N；
The module 205 finds the normalized DFT coefficients, specifically: the signal first order difference sequence
Figure BDA0002580526450000067
Normalized DFT coefficient of P1(m1) The calculation formula is
Figure BDA0002580526450000068
The second order difference sequence of the signal
Figure BDA0002580526450000069
Normalized DFT coefficient of P2(m2) The calculation formula is
Figure BDA00025805264500000610
Figure BDA00025805264500000611
The module 206 calculates a center frequency, specifically: the signal first order difference sequence
Figure BDA00025805264500000612
Has a center frequency of
Figure BDA00025805264500000613
The calculation formula is
Figure BDA00025805264500000614
The second order difference sequence of the signal
Figure BDA00025805264500000615
Has a center frequency of
Figure BDA00025805264500000616
The calculation formula is
Figure BDA00025805264500000617
Δ f is the sampling frequency of the signal sequence S;
module 207 determines the Jeffery differenceThe body is as follows: the nth Jeffery difference is recorded as HnThe calculation formula is
Figure BDA00025805264500000618
Wherein D isJIs a Jeffery difference factor and is calculated by the formula
Figure BDA00025805264500000619
m is a summation parameter;
the module 208 calculates a state determination threshold, specifically: the state judgment threshold is recorded as0The calculation formula is
Figure BDA00025805264500000620
Figure BDA00025805264500000621
Wherein k is a summation parameter; hkIs the k-th Jeffery difference amount;
the module 209 determines the running state of the transformer, specifically: judging the nth Jeffery difference HnWhether or not it is greater than or equal to the state judgment threshold value0(ii) a If the nth Jeffery difference HnGreater than or equal to the state judgment threshold value0If so, at the nth point of the signal sequence S, the transformer is in an abnormal operation state; if the nth Jeffery difference HnLess than the state judgment threshold0Then at the nth point of the signal sequence S the transformer is in a normal operating state.
The following provides an embodiment for further illustrating the invention
FIG. 3 is a flow chart illustrating an embodiment of the present invention. As shown in fig. 3, the method specifically includes the following steps:
step 301, acquiring a signal sequence S acquired according to a time sequence;
step 302 generates a first order difference sequence of signals, specifically: the nth signal first order difference sequence is recorded as
Figure BDA00025805264500000622
To its first place1 element is 0 and the ith element is
Figure BDA00025805264500000623
Wherein, N is a sequence number and has a value range of N ═ 1,2, ·, N; n is the length of the signal sequence S; siFor the i-th element of the signal sequence S,
Figure BDA0002580526450000071
is the | i-1| > of the signal sequence SNThe element, i is the element serial number, and the value range is i ═ 1,2, ·, n; (| ventilation)NRepresenting the remainder operation modulo N;
step 303 finds a second order difference sequence of the signal, specifically: the nth signal second order difference sequence is recorded as
Figure BDA0002580526450000072
The 1 st element is 0; the ith element is
Figure BDA0002580526450000073
Wherein the content of the first and second substances,
Figure BDA0002580526450000074
is the | i-2 |' of the signal sequence SNThe number of the elements is one,
step 304, calculating DFT transform coefficients, specifically: the nth signal first order difference sequence
Figure BDA0002580526450000075
DFT transform coefficient of F1(m1) The formula is
Figure BDA0002580526450000076
The nth second order difference sequence of the signal
Figure BDA0002580526450000077
DFT transform coefficient of F2(m2) (ii) a It is obtained by the formula
Figure BDA0002580526450000078
Wherein m is1For the first order difference sequence of the signal
Figure BDA0002580526450000079
The value range of the DFT transform coefficient sequence number of (1) is m1＝1,2,···,N；m2For the second order difference sequence of the signal
Figure BDA00025805264500000710
The value range of the DFT transform coefficient sequence number of (1) is m2＝1,2,···,N；
Step 305 finds the normalized DFT coefficients, specifically: the signal first order difference sequence
Figure BDA00025805264500000711
Normalized DFT coefficient of P1(m1) The calculation formula is
Figure BDA00025805264500000712
The second order difference sequence of the signal
Figure BDA00025805264500000713
Normalized DFT coefficient of P2(m2) The calculation formula is
Figure BDA00025805264500000714
Figure BDA00025805264500000715
Step 306, calculating a center frequency, specifically: the signal first order difference sequence
Figure BDA00025805264500000716
Has a center frequency of
Figure BDA00025805264500000717
The calculation formula is
Figure BDA00025805264500000718
The second order difference sequence of the signal
Figure BDA00025805264500000719
Has a center frequency of
Figure BDA00025805264500000720
The calculation formula is
Figure BDA00025805264500000721
Δ f is the sampling frequency of the signal sequence S;
step 307, calculating Jeffery difference, specifically: the nth Jeffery difference is recorded as HnThe calculation formula is
Figure BDA00025805264500000722
Wherein D isJIs a Jeffery difference factor and is calculated by the formula
Figure BDA00025805264500000723
m is a summation parameter;
step 308, obtaining a state judgment threshold specifically as follows: the state judgment threshold is recorded as0The calculation formula is
Figure BDA00025805264500000724
Figure BDA00025805264500000725
Wherein k is a summation parameter; hkIs the k-th Jeffery difference amount;
step 309, determining the running state of the transformer, specifically: judging the nth Jeffery difference HnWhether or not it is greater than or equal to the state judgment threshold value0(ii) a If the nth Jeffery difference HnGreater than or equal to the state judgment threshold value0If so, at the nth point of the signal sequence S, the transformer is in an abnormal operation state; if the nth Jeffery difference HnLess than the state judgment threshold0Then at the nth point of the signal sequence S the transformer is in a normal operating state.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. For the system disclosed by the embodiment, the description is simple because the system corresponds to the method disclosed by the embodiment, and the relevant part can be referred to the method part for description.
The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.

Claims (2)

1. A method for detecting vibration and noise of a running state of a transformer by utilizing Jeffery difference is characterized by comprising the following steps of:
step 101, acquiring a signal sequence S acquired according to a time sequence;
step 102 generates a first order difference sequence of signals, specifically: the nth signal first order difference sequence is recorded as
Figure FDA0002580526440000011
The 1 st element is 0 and the ith element is
Figure FDA00025805264400000124
Wherein, N is a sequence number and has a value range of N ═ 1,2, ·, N; n is the length of the signal sequence S; siFor the i-th element of the signal sequence S,
Figure FDA00025805264400000125
is the | i-1| > of the signal sequence SNThe element, i is the element serial number, and the value range is i ═ 1,2, ·, n; (| ventilation)NRepresenting the remainder operation modulo N;
step 103, calculating a second order difference sequence of the signal, specifically: second order difference of nth signalSubsequence is denoted as
Figure FDA0002580526440000012
The 1 st element is 0; the ith element is
Figure FDA00025805264400000126
Wherein the content of the first and second substances,
Figure FDA00025805264400000127
is the | i-2 |' of the signal sequence SNThe number of the elements is one,
step 104, calculating a DFT transform coefficient, specifically: the nth signal first order difference sequence
Figure FDA0002580526440000013
DFT transform coefficient of F1(m1) The formula is
Figure FDA0002580526440000014
Figure FDA0002580526440000015
The nth second order difference sequence of the signal
Figure FDA0002580526440000016
DFT transform coefficient of F2(m2) (ii) a It is obtained by the formula
Figure FDA0002580526440000017
Wherein m is1For the first order difference sequence of the signal
Figure FDA0002580526440000018
The value range of the DFT transform coefficient sequence number of (1) is m1＝1,2,···,N；m2For the second order difference sequence of the signal
Figure FDA0002580526440000019
DFT transform coefficients ofSerial number with value range of m2＝1,2,···,N；
Step 105, obtaining a normalized DFT coefficient, specifically: the signal first order difference sequence
Figure FDA00025805264400000110
Normalized DFT coefficient of P1(m1) The calculation formula is
Figure FDA00025805264400000111
Figure FDA00025805264400000112
The second order difference sequence of the signal
Figure FDA00025805264400000113
Normalized DFT coefficient of P2(m2) The calculation formula is
Figure FDA00025805264400000114
Step 106, calculating a center frequency, specifically: the signal first order difference sequence
Figure FDA00025805264400000115
Has a center frequency of
Figure FDA00025805264400000116
The calculation formula is
Figure FDA00025805264400000117
The second order difference sequence of the signal
Figure FDA00025805264400000118
Has a center frequency of
Figure FDA00025805264400000119
The calculation formula is
Figure FDA00025805264400000120
Δ f is the sampling frequency of the signal sequence S;
step 107, calculating Jeffery difference, specifically: the nth Jeffery difference is recorded as HnThe calculation formula is
Figure FDA00025805264400000121
Wherein D isJIs a Jeffery difference factor and is calculated by the formula
Figure FDA00025805264400000122
m is a summation parameter;
step 108, obtaining a state judgment threshold, specifically: the state judgment threshold is recorded as0The calculation formula is
Figure FDA00025805264400000123
Wherein k is a summation parameter; hkIs the k-th Jeffery difference amount;
step 109, judging the running state of the transformer, specifically: judging the nth Jeffery difference HnWhether or not it is greater than or equal to the state judgment threshold value0(ii) a If the nth Jeffery difference HnGreater than or equal to the state judgment threshold value0If so, at the nth point of the signal sequence S, the transformer is in an abnormal operation state; if the nth Jeffery difference HnLess than the state judgment threshold0Then at the nth point of the signal sequence S the transformer is in a normal operating state.
2. A transformer operation state vibration and noise detection system utilizing Jeffery difference quantity is characterized by comprising the following components:
the module 201 acquires a signal sequence S acquired in time sequence;
the module 202 generates a first order difference sequence of signals, specifically: the nth signal first order difference sequence is recorded as
Figure FDA0002580526440000021
The 1 st element is 0 and the ith element is
Figure FDA00025805264400000220
Wherein, N is a sequence number and has a value range of N ═ 1,2, ·, N; n is the length of the signal sequence S; siFor the i-th element of the signal sequence S,
Figure FDA00025805264400000221
is the | i-1| > of the signal sequence SNThe element, i is the element serial number, and the value range is i ═ 1,2, ·, n; (| ventilation)NRepresenting the remainder operation modulo N;
the module 203 calculates a second order difference sequence of the signal, specifically: the nth signal second order difference sequence is recorded as
Figure FDA0002580526440000022
The 1 st element is 0; the ith element is
Figure FDA00025805264400000222
Wherein the content of the first and second substances,
Figure FDA00025805264400000223
is the | i-2 |' of the signal sequence SNThe number of the elements is one,
the module 204 calculates DFT transform coefficients, specifically: the nth signal first order difference sequence
Figure FDA0002580526440000023
DFT transform coefficient of F1(m1) The formula is
Figure FDA0002580526440000024
Figure FDA0002580526440000025
The nth second order difference sequence of the signal
Figure FDA0002580526440000026
DFT transform coefficient of F2(m2) (ii) a It is obtained by the formula
Figure FDA0002580526440000027
Wherein m is1For the first order difference sequence of the signal
Figure FDA0002580526440000028
The value range of the DFT transform coefficient sequence number of (1) is m1＝1,2,···,N；m2For the second order difference sequence of the signal
Figure FDA0002580526440000029
The value range of the DFT transform coefficient sequence number of (1) is m2＝1,2,···,N；
The module 205 finds the normalized DFT coefficients, specifically: the signal first order difference sequence
Figure FDA00025805264400000210
Normalized DFT coefficient of P1(m1) The calculation formula is
Figure FDA00025805264400000211
Figure FDA00025805264400000212
The second order difference sequence of the signal
Figure FDA00025805264400000213
Normalized DFT coefficient of P2(m2) The calculation formula is
Figure FDA00025805264400000214
The module 206 calculates a center frequency, specifically: the signal first order difference sequence
Figure FDA00025805264400000215
Has a center frequency of
Figure FDA00025805264400000216
The calculation formula is
Figure FDA00025805264400000217
The second order difference sequence of the signal
Figure FDA00025805264400000218
Has a center frequency of
Figure FDA00025805264400000219
The calculation formula is
Figure FDA0002580526440000031
Δ f is the sampling frequency of the signal sequence S;
the module 207 calculates Jeffery difference, specifically: the nth Jeffery difference is recorded as HnThe calculation formula is
Figure FDA0002580526440000032
Wherein D isJIs a Jeffery difference factor and is calculated by the formula
Figure FDA0002580526440000033
m is a summation parameter;
the module 208 calculates a state determination threshold, specifically: the state judgment threshold is recorded as0The calculation formula is
Figure FDA0002580526440000034
Wherein k is a summation parameter; hkIs the k-th Jeffery difference amount;
the module 209 determines the running state of the transformer, specifically: judging the nth Jeffery difference HnWhether or not it is greater than or equal to the state judgment threshold value0(ii) a If it is firstn of said Jeffery differences HnGreater than or equal to the state judgment threshold value0If so, at the nth point of the signal sequence S, the transformer is in an abnormal operation state; if the nth Jeffery difference HnLess than the state judgment threshold0Then at the nth point of the signal sequence S the transformer is in a normal operating state.
CN202010666126.8A 2020-07-13 2020-07-13 Transformer running state vibration and noise detection method and system by utilizing Jeffery difference Withdrawn CN111780868A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112307998A (en) * 2020-11-06 2021-02-02 华北电力大学 Transformer running state vibration and sound detection method and system by means of mode judgment
CN112327084A (en) * 2020-11-03 2021-02-05 华北电力大学 Method and system for detecting vibration and sound of running state of transformer by utilizing equidistant transformation

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112327084A (en) * 2020-11-03 2021-02-05 华北电力大学 Method and system for detecting vibration and sound of running state of transformer by utilizing equidistant transformation
CN112307998A (en) * 2020-11-06 2021-02-02 华北电力大学 Transformer running state vibration and sound detection method and system by means of mode judgment
CN112307998B (en) * 2020-11-06 2021-11-19 华北电力大学 Transformer running state vibration and sound detection method and system by means of mode judgment

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