Three-phase adaptive reclosing method and system for wind farm transmission lines based on parallel reactor current

Patent metadata

Field	Value
Publication number	US-2026018887-A1
Application number	US-202519026671-A
Country	US
Kind code	A1
Filing date	Jan 17, 2025
Priority date	Jul 15, 2024
Publication date	Jan 15, 2026
Grant date	—

Abstract

A three-phase adaptive reclosing method and system for wind farm transmission lines based on parallel reactor current is provided. When a phase to phase or three-phase fault occurs in the transmission line, the circuit breakers at both ends trip. The current transformer is used to sample the three-phase current signal of the parallel reactor, calculate the differential mode current of the parallel reactor, and perform zero crossing detection to construct a fault nature identification criterion. The fault nature is determined within the maximum discrimination time limit combined with the sliding time window. For permanent faults, the reclosing device is locked; for transient faults, calculate the time when the fault disappears and determine the reclosing time, and open the reclosing device. The method and system identifies the nature of faults by detecting whether the differential current of parallel reactors crosses the zero axis, with low sampling rate requirements, and small errors.

First claim

1 . A three-phase adaptive reclosing method for wind farm transmission lines based on parallel reactor current, comprising the following steps:
Step 1: after a phase to phase or three-phase fault occurs in a transmission line, isolating the transmission line from the phase to phase or three-phase fault; Step 2: using current transformers to sample three-phase current signals of parallel reactors; Step 3: calculating a differential mode current of the parallel reactors within a sliding time window; Step 4: performing zero crossing detection on the differential mode current of the parallel reactors; Step 5: identifying a nature of the phase to phase or three-phase fault within a maximum discrimination time limit, and when the phase to phase or three-phase fault is determined to be a permanent fault, outputting a locking reclosing signal; when the phase to phase or three-phase fault is determined to be a transient fault, proceeding to Step6; and Step 6: calculating a time when the phase to phase or three-phase fault disappears and determining a three-phase reclosing time, and outputting a reclosing signal; wherein Step 4 comprises:
Step 4.1: calculating a product of maximum and minimum values of the differential mode current within the sliding time window:

R
k

=

i

max
,
k

×

i

min
,
k

wherein k represents a sliding window number; i max,k and i min,k respectively represent the maximum and minimum values of the differential mode current within a k-th time window; and
Step 4.2: calculating a sign function value of R k within the sliding time window:

sgn
⁢

(

R
k

)

=

{

1
,

R
k

>
0

-
1

,

R
k

⩽
0

;

wherein Step 5 comprises:
Step 5.1: setting the maximum discrimination time limit T max ; and
Step 5.2: constructing fault nature identification criteria, when j-th, j+1 and j+2-nd sliding time windows occur within the maximum discrimination time limit, and satisfy:

sgn
⁢

(

R
j

)

=

-
1

&

⁢

sgn
⁡
(

R

j
+
1

)

=

-
1

&

⁢

sgn
⁡
(

R

j
+
2

)

=

-
1

 the phase to phase or three-phase fault is determined as the transient fault, otherwise the phase to phase or three-phase fault is determined as the permanent fault; wherein Step 6 comprises:
Step 6.1: according to the sliding window number j obtained in Step 5.2, calculating the time t end when the phase to phase or three-phase fault disappears:

t
end

=

jT
s

+

t
trip

 wherein T s is a length of the sliding time window, and t trip is the time when a circuit breaker trips; and
Step 6.2: calculating the three-phase reclosing time t close based on an arc insulation recovery time T re , and outputting the reclosing signal:

t
close

=

t
end

+

T
re

.

2 . The three-phase adaptive reclosing method for the wind farm transmission lines based on the parallel reactor current according to claim 1 , wherein in Step1, after the phase to phase or three-phase fault occurs in the transmission line, the circuit breakers installed at both ends of a fault line trip to isolate the phase to phase or three-phase fault.

3 . The three-phase adaptive reclosing method for the wind farm transmission lines based on the parallel reactor current according to claim 1 , wherein Step3 comprises:
Step3.1: defining a sliding time window with a time length of T s and a sliding factor of s; Step3.2: calculating the differential mode current of a parallel reactor by a following

Assignees

• Univ Kunming Science & Technology

Inventors

• Shu Hongchun
• Dai Yue
• Tang Yutao
• Han Yiming
• Zhao Hongfang
• Lou Weijie

Classifications

• H02J3/381 Primary

  Dispersed generators · CPC title

• H02J2101/28

  Wind energy · CPC title

• H02J3/0012

  characterised by the contingency detection means in AC networks, e.g. using phasor measurement units [PMU], synchrophasors or contingency analysis · CPC title

• H02J3/00125 Primary

  Transmission line or load transient problems, e.g. overvoltage, resonance or self-excitation of inductive loads (H02J3/01 takes precedence) · CPC title

• H02H1/0007

  concerning the detecting means (in general G01R or other subclasses of G01; reed switches H01H71/2445) · CPC title