Grounding grid breakpoint diagnostic method for transient electromagnetic method

Patent metadata

Field	Value
Publication number	US-9651604-B2
Application number	US-201414897501-A
Country	US
Kind code	B2
Filing date	Oct 23, 2014
Priority date	Nov 21, 2013
Publication date	May 16, 2017
Grant date	May 16, 2017

Abstract

A grounding grid breakpoint diagnostic method for a transient electromagnetic method, based on a transient electromagnetic detection apparatus. The method comprises: ( 101 ) disposing a test line at a position above a grounding grid to be diagnosed on the ground, and determining coordinates of a detection point; ( 102 ) obtaining information about coordinates of the detection point, and coinciding the center of the transient electromagnetic detection apparatus with the coordinates of the detection point; ( 103 ) performing, by the transient electromagnetic detection apparatus, measurement along the test line point by point, so as to obtain measurement data; ( 104 ) processing, by using diagram forming software, the measurement data to form a longitudinal resistivity cross-section diagram of the detection point according to a preset formula; ( 105 ) determining whether a breakpoint occurs at the detection point according to the longitudinal resistivity cross-section diagram. The method does not depend on a design material of a grounding grid, and can implement non-excavation grounding grid breakpoint diagnosis without outage, thereby reducing economic losses in a diagnosis process.

First claim

What is claimed is:

1. A grounding grid breakpoint diagnostic method, based on a transient electromagnetic detection apparatus including a transmitting system and a receiving system, said transmitting system including a battery pack, a transmitter and a transmitting coil, said receiving system including a receiver and a receiving coil, wherein said transmitting coil has its two ends respectively connected to current output ends of said transmitter, said battery pack has its anode connected to a positive power supply terminal of said transmitter and its cathode connected to a negative power supply terminal of said transmitter, and said receiving coil has its two ends respectively connected to signal acquisition lines of said receiver, characterized in that the method comprises:
disposing a test line at a position above a grounding grid to be diagnosed on the ground, and determining coordinates of a detection point;
obtaining information about coordinates of the detection point, and coinciding the center of the transient electromagnetic detection apparatus with the coordinates of the detection point;
performing, by the transient electromagnetic detection apparatus, measurement along the test line point by point, so as to obtain measurement data;
processing, by using diagram forming software, the measurement data to form a longitudinal resistivity cross-section diagram of the detection point according to a preset formula; and
determining whether a breakpoint occurs at the detection point according to the longitudinal resistivity cross-section diagram.

2. The method as recited in claim 1 , characterized in that the processing, by using diagram forming software, the measurement data to form a longitudinal resistivity cross-section diagram of the detection point according to a preset formula is particularly:
starting the transmitter of the transient electromagnetic detection apparatus to generate bipolar rectangular pulse current and establish a primary pulsed magnetic field;
observing and sensing a secondary vortex field using the receiving coil of the transient electromagnetic detection apparatus and converting a secondary voltage signal stored in the receiver of the transient electromagnetic detection apparatus into a magnetic field signal;
constructing and calculating a function of transient field parameters f(u) using a formula of a vertical component B z of the secondary field

B
z

=

Iμ

2
⁢
a

⁡

[

3

πμ

⁢

ⅇ

-

u
2

+

(

1
-

3

2
⁢

u
2

)

⁢

erf
⁡

(
u
)

]

,

⁢

the
⁢

⁢

f
⁡

(
u
)

=

1

u
2

⁡

[

3
⁢
u

π

⁢

ⅇ

-

u
2

+

(

u
2

-

3
2

)

⁢

erf
⁡

(
u
)

]

-

2
⁢

aB
z

μ
⁢

⁢
I

,

and calculating apparent resistivity ρ(t), the

ρ
⁡

(
t
)

=

Assignees

• State Grid Chongqing Electric Power Co Electric Power Res Inst
• State Grid Corp China
• State Gride Corp Of China

Inventors

• Hou Xingzhe
• Fu Jin
• Wang Qian
• Bao Minghui
• Wu Gaolin
• Tang Shiyu
• Ji Yongliang
• Chen Wei

Classifications

• G01R31/58

  Testing of lines, cables or conductors (testing of electric windings G01R31/72) · CPC title

• G01R31/086

  in power transmission or distribution networks, i.e. with interconnected conductors · CPC title

• G01R31/085

  in power transmission or distribution lines, e.g. overhead · CPC title

• G01R31/08 Primary

  Locating faults in cables, transmission lines, or networks · CPC title

• G01R31/083

  in cables, e.g. underground · CPC title