# US 12,216,182 B2 · Device and method for detecting defects of high-voltage cable cross-bonded grounding system

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- Number: US 12,216,182 B2
- Document ID: US12216182B2
- Status: Granted
- Kind: B2
- Application number: 18/001,706
- Filed: 2022-08-04
- Published: 2024-04-04
- Granted: 2025-02-04
- Earliest claimed: 2021-11-02
- Assignees: State Grid Jiangsu Electric Power Co., Ltd. Research Institute; State Grid Jiangsu Electric Power Co., Ltd.; Jiangsu Electric Power Research Institute Co., Ltd.
- Applicants: State Grid Jiangsu Electric Power Co., Ltd. Research Institute; State Grid Jiangsu Electric Power Co., Ltd.; Jiangsu Electric Power Research Institute Co., Ltd.
- Inventors: Jingying Cao; Qiang Huang; Jinggang Yang; Jie Chen; Rong Sun; Jianjun Liu; Xiao Tan; Libin Hu; Chenying Li; Wei Zhang
- Web page: https://patentgrep.com/patent/US12216182B2

## CPC

- G01R 31/52: Testing for short-circuits, leakage current or ground faults
- G01R 31/66: Testing of connections, e.g. of plugs or non-disconnectable joints (testing for incorrect line connections G01R31/55)
- G01R 27/02: Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant (by measuring phase angle only G01R25/00)
- G01R 31/58: Testing of lines, cables or conductors (testing of electric windings G01R31/72)
- Y04S 10/52: Outage or fault management, e.g. fault detection or location
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- Y04S: SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS

## Abstract

Disclosed are a device and method for detecting defects of a high-voltage cable cross-bonded grounding system. The method selects a protective grounding box of a cross-bonded grounding system, respectively connects a signal excitation coupler to A-phase, B-phase and C-phase coaxial cables of the protective grounding box, selects a stable signal with a frequency different from a power frequency or a field interference frequency, and tests effective current values and phases responded by the A-phase, B-phase and C-phase coaxial cables when the stable signal with the frequency F1 is injected into the A-phase, B-phase and C-phase coaxial cables of the protective grounding box; and obtains resistances and inductances of branch circuits of the cable cross-bonded grounding system by calculation according to measurement data, and determines if the cable cross-bonded grounding system has a connection defect.

## Claims

### Claim 1

A device for determining connection defects of a high-voltage cable cross-bonded grounding system, comprising: an AC power supply, a signal acquisition device, an input current test device, a signal excitation coupler, an output current test device, and test sensors, wherein:
the AC power supply is connected to the signal excitation coupler and is used for providing an alternating current with a frequency different from a power frequency and a field interference frequency for the signal excitation coupler;
the signal excitation coupler is an annular closed loop installed on coaxial cables of a cross-bonded grounding lead which is connected to a cable cross-bonded grounding system, and is used for injecting a stable current signal into the cable cross-bonded grounding system based on the alternated current with the frequency different from the power frequency and the field interference frequency from the AC power supply;
the AC power supply is connected to the input current test device, and the input current test device is connected to the signal excitation coupler and is used for testing an effective value and phase of a current output by the AC power supply;
the output current test device is connected to the test sensors installed on the coaxial cables of the cross-bonded grounding lead which is connected to the cable cross-bonded grounding system, and is used for testing effective current values and phases responded by the coaxial cables of the cross-bonded grounding system at an excitation frequency, the input current test device and the output current test device are both connected to the signal acquisition device, and the signal acquisition device is used for sampling current information output by the input current test device and the output current test device.

### Claim 2 (depends on 1)

The device for determining connection defects of a high-voltage cable cross-bonded grounding system according to claim 1, wherein, the input current test device is an AC measurement device.

### Claim 3 (depends on 1)

A method for determining connection defects of a high-voltage cable cross-bonded grounding system by the device according to claim 1, comprising the following steps:
selecting, by means of the AC power supply, a stable current signal with a frequency F1 different from a power frequency and a field interference frequency;
respectively injecting, by means of the signal excitation coupler, the stable current signal with the frequency F1 into A-phase, B-phase and C-phase coaxial cables into a cross-bonding box of the cable cross-bonded grounding system;
under the condition where the stable current signal with the frequency F1 is injected into the A-phase, B-phase and C-phase coaxial cables, testing, by means of the input current test device, an effective value and phase of a current output by the AC power supply, and testing, by means of the output current test device, effective current values and phases responded by the A-phase, B-phase and C-phase coaxial cables of the cable cross-bonded grounding system, calculating resistances of branch circuits of the cable cross-bonded grounding system based on test data which include the effective value and phase of the current output by the AC power supply and the effective current values and phases responded by the A-phase, B-phase and C-phase coaxial cables of the cable cross-bonded grounding system; and
determining the connection defect of the high-voltage cable cross-bonded grounding system based on the calculated resistances.

### Claim 4 (depends on 3)

The method for determining connection defects of a high-voltage cable cross-bonded grounding system according to claim 3, wherein, the effective value and phase of the current output by the AC power supply are tested by means of the input current test device, and an induced voltage of the cable cross-bonded grounding system is obtained by calculation according to the following formula:
U1i∠αi=k1*F1*Ii*[cos αi+j*sin αi]=Pi+j*Qi;
αi=βi+θi;
where, U1i∠αi is the induced voltage of the cable cross-bonded grounding system in a phase αi, αi is an induced phase, Ii and βi are the effective value and phase of the current output by the AC power supply, Pi is a real part of a complex number U1i, Qi is an imaginary part of the complex number U1i, k1 is a proportionality coefficient, θi is a phase difference, and i=1, 2, 3 indicates an ith coupled injection;
U1i and αi are obtained by calculation according to the test data, and then Pi and Qi are obtained.

### Claim 5 (depends on 4)

The method for determining connection defects of a high-voltage cable cross-bonded grounding system according to claim 4, wherein, the effective current values and phases responded by the A-phase, B-phase and C-phase coaxial cables of the cable cross-bonded grounding system are tested by means of the output current test device, and currents and phases of leads in the coaxial cables are calculated as follows:
when the stable current signal with the frequency F1 is injected into the A-phase coaxial cable in a coupled manner, currents and phases of the leads in the coaxial cables are calculated by:
[
1
1
0
1
0
1
0
1
1
]
-
1
·
[
IA_
⁢
1
*
cos
⁡
(
γ
⁢
A_
⁢
1
)
+
j
*
IA_
⁢
1
*
sin
⁡
(
γ
⁢
A_
⁢
1
)
IB_
⁢
1
*
cos
⁡
(
γ
⁢
B_
⁢
1
)
+
j
*
IB_
⁢
1
*
sin
⁡
(
γ
⁢
B_
⁢
1
)
IC_
⁢
1
*
cos
⁡
(
γ
⁢
C_
⁢
1
)
+
j
*
IC_
⁢
1
*
sin
⁡
(
γ
⁢
C_
⁢
1
)
]
=
[
IAB_
⁢
1
*
cos
⁡
(
γ
⁢
AB_
⁢
1
)
+
j
*
IAB_
⁢
1
*
sin
⁡
(
γ
⁢
AB_
⁢
1
)
IBC_
⁢
1
*
cos
⁡
(
γ
⁢
BC_
⁢
1
)
+
j
*
IBC_
⁢
1
*
sin
⁡
(
γ
⁢
BC_
⁢
1
)
ICA_
⁢
1
*
cos
⁡
(
γ
⁢
CA_
⁢
1
)
+
j
*
IBC_
⁢
1
*
sin
⁡
(
γ
⁢
CA_
⁢
1
)
]
=
[
X
⁢
11
+
j
*
Y
⁢
11
X
⁢
12
+
j
*
Y
⁢
12
X
⁢
13
+
j
*
Y
⁢
13
]
;
where, IA_1, IB_1 and IC_1 are effective current values responded by the A-phase, B-phase and C-phase coaxial cables when the stable current signal with the frequency F1 is injected into the A-phase coaxial cable in the coupled manner, γA_1, γB_1 and γC_1 are current phases responded by the A-phase, B-phase and C-phase coaxial cables when the stable current signal with the frequency F1 is injected into the A-phase coaxial cable in the coupled manner, IAB_1, IBC_1 and ICA 1 are currents of a lead A1-B2, a lead B1-C2 and a lead C1-A3 in the coaxial cables when the stable current signal with the frequency F1 is injected into the A-phase coaxial cable in the coupled manner, γAB_1, γBC_1 and γCA_1 are current phases of the lead A1-B2, the lead B1-C2 and the lead C1-A3 in the coaxial cables when the stable current signal with the frequency F1 is injected into the A-phase coaxial cable in the coupled manner, X1j, j=1, 2, 3 is a real part of complex numbers IAB_1, IBC_1 and ICA_1, and Y1j is an imaginary part of the complex numbers IAB_1, IBC_1 and ICA_1;
when the stable current signal with the frequency F1 is injected into the B-phase coaxial cable in a coupled manner, currents and phases of the leads in the coaxial cables are calculated by:
[
1
1
0
1
0
1
0
1
1
]
-
1
·
[
IA_
⁢
2
*
cos
⁡
(
γ
⁢
A_
⁢
2
)
+
j
*
IA_
⁢
2
*
sin
⁡
(
γ
⁢
A_
⁢
2
)
IB_
⁢
2
*
cos
⁡
(
γ
⁢
B_
⁢
2
)
+
j
*
IB_
⁢
2
*
sin
⁡
(
γ
⁢
B_
⁢
2
)
IC_
⁢
2
*
cos
⁡
(
γ
⁢
C_
⁢
2
)
+
j
*
IC_
⁢
2
*
sin
⁡
(
γ
⁢
C_
⁢
2
)
]
=
[
IAB_
⁢
2
*
cos
⁡
(
γ
⁢
AB_
⁢
2
)
+
j
*
IAB_
⁢
2
*
sin
⁡
(
γ
⁢
AB_
⁢
2
)
IBC_
⁢
2
*
cos
⁡
(
γ
⁢
BC_
⁢
2
)
+
j
*
IBC_
⁢
2
*
sin
⁡
(
γ
⁢
BC_
⁢
2
)
ICA_
⁢
2
*
cos
⁡
(
γ
⁢
CA_
⁢
2
)
+
j
*
IBC_
⁢
2
*
sin
⁡
(
γ
⁢
CA_
⁢
2
)
]
=
[
X
⁢
21
+
j
*
Y
⁢
21
X
⁢
22
+
j
*
Y
⁢
22
X
⁢
23
+
j
*
Y
⁢
23
]
;
where, IA_2, IB_2 and IC_2 are effective current values responded by the A-phase, B-phase and C-phase coaxial cables when the stable current signal with the frequency F1 is injected into the B-phase coaxial cable in the coupled manner, γA_2, γB_2 and γC_2 are current phases responded by the A-phase, B-phase and C-phase coaxial cables when the stable current signal with the frequency F1 is injected into the B-phase coaxial cable in the coupled manner, IAB_2, IBC 2 and ICA 2 are currents of the lead A1-B2, the lead B1-C2 and the lead C1-A3 in the coaxial cables when the stable current signal with the frequency F1 is injected into the B-phase coaxial cable in the coupled manner, γAB_2, γBC_2 and γCA_2 are current phases of the lead A1-B2, the lead B1-C2 and the lead C1-A3 in the coaxial cables when the stable current signal with the frequency F1 is injected into the B-phase coaxial cable in the coupled manner, X2j, j=1, 2, 3 is a real part of complex numbers IAB_2, IBC_2 and ICA_2, and Y2j is an imaginary part of the complex numbers IAB_2, IBC_2 and ICA_2;
when the stable current signal with the frequency F1 is injected into the C-phase coaxial cable in a coupled manner, currents and phases of the leads in the coaxial cables are calculated by:
[
1
1
0
1
0
1
0
1
1
]
-
1
·
[
IA_
⁢
3
*
cos
⁡
(
γ
⁢
A_
⁢
3
)
+
j
*
IA_
⁢
3
*
sin
⁡
(
γ
⁢
A_
⁢
3
)
IB_
⁢
3
*
cos
⁡
(
γ
⁢
B_
⁢
3
)
+
j
*
IB_
⁢
3
*
sin
⁡
(
γ
⁢
B_
⁢
3
)
IC_
⁢
3
*
cos
⁡
(
γ
⁢
C_
⁢
3
)
+
j
*
IC_
⁢
3
*
sin
⁡
(
γ
⁢
C_
⁢
3
)
]
=
[
IAB_
⁢
3
*
cos
⁡
(
γ
⁢
AB_
⁢
3
)
+
j
*
IAB_
⁢
3
*
sin
⁡
(
γ
⁢
AB_
⁢
3
)
=
X
⁢
31
+
j
*
Y
⁢
31
IBC_
⁢
3
*
cos
⁡
(
γ
⁢
BC_
⁢
3
)
+
j
*
IBC_
⁢
3
*
sin
⁡
(
γ
⁢
BC_
⁢
3
)
=
X
⁢
32
+
j
*
Y
⁢
32
ICA_
⁢
3
*
cos
⁡
(
γ
⁢
CA_
⁢
3
)
+
j
*
IBC_
⁢
3
*
sin
⁡
(
γ
⁢
CA_
⁢
3
)
=
X
⁢
33
+
j
*
Y
⁢
33
]
=
[
X
⁢
31
+
j
*
Y
⁢
31
X
⁢
32
+
j
*
Y
⁢
32
X
⁢
33
+
j
*
Y
⁢
33
]
;
where, IA_3, IB_3 and IC_3 are effective current values responded by the A-phase, B-phase and C-phase coaxial cables when the stable current signal with the frequency F1 is injected into the C-phase coaxial cable in the coupled manner, γA_3, γB_3 and γC_3 are current phases responded by the A-phase, B-phase and C-phase coaxial cables when the stable current signal with the frequency F1 is injected into the C-phase coaxial cable in the coupled manner, IAB_3, IBC_3 and ICA 3 are currents of the lead A1-B2, the lead B1-C2 and the lead C1-A3 in the coaxial cables when the stable current signal with the frequency F1 is injected into the C-phase coaxial cable in the coupled manner, γAB_3, γBC_3 and γCA_3 are current phases of the lead A1-B2, the lead B1-C2 and the lead C1-A3 in the coaxial cables when the stable current signal with the frequency F1 is injected into the C-phase coaxial cable in the coupled manner, X3j, j=1, 2, 3 is a real part of complex numbers IAB_3, IBC_3 and ICA_3, and Y3j is an imaginary part of the complex numbers IAB 3, IBC_3 and ICA 3.

### Claim 6 (depends on 5)

The method for determining connection defects of a high-voltage cable cross-bonded grounding system according to claim 5, wherein, the resistances of the branch circuits of the cable cross-bonded grounding system are calculated by:
[
X
⁢
11
-
X
⁢
12
0
-
Y
⁢
11
Y
⁢
12
0
Y
⁢
11
-
Y
⁢
12
0
X
⁢
11
-
X
⁢
12
0
X
⁢
21
0
-
X
⁢
23
-
Y
⁢
21
0
Y
⁢
23
Y
⁢
21
0
-
Y
⁢
23
X
⁢
21
0
-
X
⁢
23
0
X
⁢
32
-
X
⁢
33
0
-
Y
⁢
32
Y
⁢
33
0
Y
⁢
32
-
Y
⁢
33
0
X
⁢
32
-
X
⁢
33
]
·
[
R
⁢
1
R
⁢
2
R
⁢
3
X
⁢
1
X
⁢
2
X
⁢
3
]
=
[
P
⁢
1
Q
⁢
1
P
⁢
2
Q
⁢
2
P
⁢
3
Q
⁢
3
]
;
where, R1, R2 and R3 are resistances of a branch circuit A1-B2-C3, a branch circuit B1-C2-A3 and a branch circuit C1-A2-B3 of the cable cross-bonded grounding system respectively, and X1, X2 and X3 are inductances of the branch circuit A1-B2-C3, the branch circuit B1-C2-A3 and the branch circuit C1-A2-B3 of the cable cross-bonded grounding system respectively.

### Claim 7 (depends on 6)

The method for determining connection defects of a high-voltage cable cross-bonded grounding system according to claim 6, wherein, if any one of the following two conditions is met, it is determined that the high-voltage cable cross-bonded grounding system has a defect:
A, the resistance of at least one of the branch circuits of the cable cross-bonded grounding system is greater than or equal to 0.3Ω;
B, a ratio of the resistances of every two of the branch circuits of the cable cross-bonded grounding system is over 1.2.