US 2025/0093208 A1 · METHOD AND SYSTEM FOR ONLINE MONITORING OF TEMPERATURE IN CURRENT TERMINAL BLOCKS BASED ON THERMAL IMAGING

Abstract

A method for online monitoring of temperature in current terminal blocks based on thermal imaging are provided, including: obtaining real-time temperature distribution information of current terminals of a terminal box; using an external communication substation to upload the obtained real-time temperature distribution information to the secondary intelligent operation-and-maintenance control platform; determining whether there is an abnormality in temperature of the current terminals, if there is an abnormality, issuing an alarm message about potential danger for an open circuit of a current secondary circuit. The method provided by the present invention has a self-verification function of measurement data and can suppress the influence of ambient temperature. Through aggregation analysis of the temperatures of different current terminals of the terminal box, historical data mining of the temperature of the same current terminal is carried out to identify the hidden dangers of the open circuit of the current secondary circuit.

A method for online monitoring of temperature in current terminal blocks based on thermal imaging, comprising:

obtaining real-time temperature distribution information of current terminals of a terminal box;
using an external communication substation to upload the obtained real-time temperature distribution information to the secondary intelligent operation-and-maintenance control platform;
determining whether there is an abnormality in temperature of the current terminals, if there is an abnormality, issuing an alarm message for potential hidden danger for an open circuit of a current secondary circuit,
wherein the determining whether there is an abnormality in the temperature of the current terminals comprises defining a reasonableness interval for measurement temperatures of the current terminals, wherein when a measured temperature Tc-i of a current terminal i is within a reasonableness threshold interval, the measured temperature of the current terminal uploaded to the secondary intelligent operation-and-maintenance control platform is initially confirmed whether it is reasonable data;
wherein when the measured temperature Tc-i of the current terminal i is outside the reasonableness threshold interval, three consecutive sampling points are determined, if Tc-i, Tc-i+1, Tc-i+2, which are three consecutive sampling points, are all outside the reasonableness interval, an alarm for thermal imaging sensor sampling abnormality is issued;
wherein if the initially confirming is to be reasonable data, theoretical temperature calibration of the current terminals is performed to confirm that a thermal imaging sensor measurement error is within an allowable range, comprising calculating the theoretical temperature Tl-i of the current terminal i based on a secondary current iII uploaded to the secondary intelligent operation-and-maintenance control platform by a power grid relay protection and fault information system, and calculating an error rate k1 between the measured temperature Tc-i and the theoretical temperature Tl-i of the current terminal i to verify the theoretical temperature;
wherein when 0≤k1≤5%, the data of the measurement temperature of the current terminal uploaded to the secondary intelligent operation-and-maintenance control platform is confirmed to be correct data, and it is to confirm that measurement data is without any errors in intermediate links of transmission and is available for determination of an abnormal temperature of a current terminal;
wherein if k1>5%, it is determined that the measurement data has errors due to intermediate transmission links, and a thermal imaging sensor sampling error alarm is issued;
wherein the real-time temperature distribution information is collected through an online temperature measurement imager processing collection to the temperature distribution information of all the current terminals of the terminal box;
wherein the temperature distribution information uploaded to the secondary intelligent operation-and-maintenance control platform, including information from a collection unit of the external communication substation, is uploaded to the secondary intelligent operation-and-maintenance control platform after processing by a management unit;
wherein the reasonableness interval for the measurement temperature of the current terminal is expressed as:
(
T
c
-
i
≥
T
h
)
⋃
(
T
c
-
i
≤
T
max
)
where, Th represents a current ambient temperature, and Tmax represents the historical highest in the measurement temperature of the current terminal;
wherein the theoretical temperature is expressed as:
P
f
=
R
*
[
1
Δ
⁢
t
⁢
∫
t
t
+
Δ
⁢
t
i
II
2
(
t
)
⁢
d
⁢
t
]
⁢
P
s
=
P
s
⁢
c
+
P
s
⁢
r
⁢
P
s
⁢
c
=
π
*
λ
f
*
(
T
l
-
i
-
T
h
)
*
N
u
⁢
0
⁢
P
s
⁢
r
=
π
*
D
*
σ
B
*
ε
*
[
(
T
l
-
i
+
2
⁢
3
⁢
7
)
4
-
(
T
h
+
2
⁢
3
⁢
7
)
4
]
⁢
T
l
-
i
=
∑
P
f
-
P
s
m
⁢
c
*
Δ
⁢
t
where, the theoretical temperature Tl-i of the current terminal i is a function of Pf and Ps, in which Pf and Ps correspond to Joule heating power and heat dissipation power, respectively, R represents resistance of the current terminal i and its secondary circuit, Δt represents a time interval for uploading the secondary current iII to the power grid relay protection and fault information system, the heat dissipation power Ps is the sum of convection heat dissipation power Psc and radiation heat dissipation power Psr, λf represents an air thermal conductivity, Th represents a ambient temperature, Nu0 represents a Nusselt number when air flow rate is 0, D represents a secondary loop path, σB represents a Stephan-Boltzmann constant, ε represents a radiation coefficient of a secondary loop wire material, m represents a mass of a secondary loop wire per unit length, and c represents an equivalent specific heat capacity of a secondary loop wire material,
wherein the theoretical temperature calibration is expressed as:
k
1
=
❘
"\[LeftBracketingBar]"
T
c
-
i
-
T
l
-
i
T
l
-
i
❘
"\[RightBracketingBar]"
*
100
⁢
%
where, k1 represents an error rate;
wherein the determining the abnormal temperature of the current terminals comprises using an interquartile range method for an aggregative analysis conducted on the measurement temperatures of current terminals of different windings within the terminal box, preliminarily screening out the current terminals with outliers in the measurement temperatures, and defining a temperature matrix measured by the current terminals of the different windings;
wherein the matrix is expressed as:
T
c
⁢
=
[
T
c
-
A
⁢
1
T
c
-
A
⁢
2
T
c
-
A
⁢
3
…
T
c
-
AN
T
c
-
B
⁢
1
T
c
-
B2
T
c
-
B
⁢
3
…
T
c
-
BN
T
c
-
C
⁢
1
T
c
-
C
⁢
2
T
c
-
C
⁢
3
…
T
c
-
CN
]
⁢
M
3
=
T
c
-
A
⁢
i
,
i
=
int
(
3
*
(
N
+
1
)
4
+
0
.
5
)
⁢
M
1
=
T
c
-
A
⁢
i
,
i
=
int
(
N
+
1
4
+
0
.
5
)
⁢
Z
=
M
3
+
1
.
5
*
(
M
3
-
M
1
)
⁢
Y
=
M
1
-
1
.
5
*
(
M
3
-
M
1
)
where, Tc-A1, Tc-A2, Tc-A3, Tc-AN correspond to the measurement temperatures of A-phase current terminals of the 1st, 2nd, 3rd, and N windings of the terminal box, respectively, Tc-B1, Tc-B2, Tc-B3, Tc-BN correspond to the measurement temperatures of B-phase current terminals of the 1st, 2nd, 3rd, and N windings of the terminal box, respectively, Tc-c1, Tc-C2, Tc-c3, Tc-CN correspond to the measurement temperatures of C-phase current terminals of the 1st, 2nd, 3rd, and N windings of the terminal box, respectively, in which upper and lower boundaries of a quartile aggregation interval (Y, Z) are defined, M3 is the 75th percentile value of all elements of Tc-A sorted from smallest to largest in columns, M1 is the 25th percentile value of all elements of Tc-A sorted from smallest to largest in columns, and int( ) represents a floor function,
wherein If Tc-i falls into the upper and lower boundaries of the quartile aggregation interval (Y, Z), it is determined that the temperature of the current terminal is not outliers and the temperature is normal, wherein if Tc-i does not fall into the upper and lower boundaries of the quartile aggregation interval (Y, Z), the current terminal i with the measurement temperature that does not fall into the upper and lower boundaries of the quartile aggregation interval (Y, Z) is screened out, and a standard deviation method is applied to performing aggregation analysis on the measurement temperature of the three-phase current terminal corresponding to current terminal i;
wherein the aggregation analysis is expressed as:
{
(
T
c
-
i
≥
T
AVE
-
3
*
sd
)
&
⁢
(
T
c
-
i
≤
T
AVE
+
3
*
s
⁢
d
)
T
AVE
=
1
3
⁢
(
T
c
-
A
⁢
i
+
T
c
-
B
⁢
i
+
T
c
-
C
⁢
i
)
s
⁢
d
=
(
T
c
-
A
⁢
i
-
T
AVE
)
2
+
(
T
c
-
B
⁢
i
-
T
AVE
)
2
+
(
T
c
-
C
⁢
i
-
T
AVE
)
2
2
where, TAVE represents an average of the measurement temperature from the three-phase current terminal corresponding to the identified current terminal i, sd represents standard deviation of the measurement temperature of the three-phase current terminal, Tc-Ai, Tc-Bi, Tc-Ci correspond to measurement temperatures of phase A, B and C current terminals, respectively, & means AND, that is, it is satisfied at the same time;
wherein when the measurement temperature Tc-i of the current terminal i does not meet aggregation analysis conditions, a phase type of current terminals with outlier temperature measurements is screened out;
wherein, after screening out the phase type of the current terminals with outlier temperature measurements, development trend of the temperature of the current terminals within the time threshold is analyzed to confirm whether there is temperature abnormality in the current terminals, wherein the measurement temperature of the current terminal at the same operating time within a preset time for the current terminal i is extracted for comparison, which is expressed as:
❘
"\[LeftBracketingBar]"
T
c
-
i
-
T
c
-
i
+
T
c
-
i
-
2
⁢
4
⁢
h
+
T
c
-
i
-
4
⁢
8
⁢
h
3
❘
"\[RightBracketingBar]"
≤
5
where, Tc-i represents the measurement temperature of current terminal i at current time, Tc-i-24h represents the measurement temperature of current terminal i at the timing 24 hours before the current time, and Tc-i-48h represents the measurement temperature of current terminal i at the timing 48 hours before the current time;
wherein when the measurement temperature of the current terminal complies with the threshold, it is judged that the temperature of the current terminal i is normal, wherein when the measurement temperature of the current terminal does not comply with the threshold, data of the current terminal at different times on the same day is analyzed and a temperature rise function Tc-i(t) of the current terminal is defined, which is expressed as:
T
c
-
i
(
t
)
=
T
c
-
i
(
t
-
Δ
⁢
t
)
-
T
c
-
i
(
t
)
Δ
⁢
t
where, Tc-i(t) is the measurement temperature of the current terminal i at time t, Tc-i(t−Δt) is the measurement temperature of the current terminal i at time t−Δt, and Δt is a time interval for the temperature of the current terminal to be uploaded;
wherein Tc-i (t) is derived to obtain a temperature rise change rate of the current terminal I, expressed as:
T
c
-
i
′
(
t
)
=
d
⁢
T
c
-
i
(
t
)
d
⁢
t
wherein statistical analysis is performed on actual temperature measurement data, and it is determined that the temperature of the current terminal i is normal when the temperature rise change rate of the current terminal i complies with the change rate threshold;
wherein the change rate threshold is expressed as:
T
c
-
i
′
(
t
)
=
❘
"\[LeftBracketingBar]"
d
⁢
T
c
-
i
(
t
)
d
⁢
t
❘
"\[RightBracketingBar]"
≤
0.
3
wherein when it does not comply with the change rate threshold, three sampling points are determined consecutively, when none of
❘
"\[LeftBracketingBar]"
d
⁢
T
c
-
i
(
t
)
dt
❘
"\[RightBracketingBar]"
,
❘
"\[LeftBracketingBar]"
d
⁢
T
c
-
i
+
1
(
t
)
dt
❘
"\[RightBracketingBar]"
,
❘
"\[LeftBracketingBar]"
d
⁢
T
c
-
i
+
2
(
t
)
dt
❘
"\[RightBracketingBar]"
complies with the change rate threshold, it is determined that the current terminal i is a current terminal in an abnormal temperature, and a corresponding secondary circuit is determined to have hidden dangers in an open circuit, thereby issuing an alarm.

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Method and system for online monitoring of temperature in current terminal blocks based on thermal imaging

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Method and system for online monitoring of temperature in current terminal blocks based on thermal imaging

Life of this patent

Abstract

Claims4