Synchronization method and wide area system protection apparatus
Provided are a synchronization method, a wide area system protection apparatus, a plant station and a computer readable storage medium. The method includes: sending to a second plant station a first data frame that includes a sequence number p and a sending timestamp of the first data frame; receiving a second data frame sent by the second plant station, and recording a receiving timestamp of the second data frame, the second data frame including a sequence number q of the second data frame, a sending timestamp of the second data frame and a receiving timestamp of the first data frame, and the first data frame being adjacent to the second frame on the second plant station; calculating a time phase difference and a crystal oscillator frequency deviation between the first plant station and the second plant station; and adjusting time and a clock frequency of the first plant station.
1. A synchronization method, comprising:
at a wide area system protection apparatus, a network topology framework of which comprises a first plant station and a second plant station:
sending a first data frame to the second plant station by the first plant station, wherein the first data frame comprises a sequence number p of the first data frame and a sending timestamp T st[q] of the first data frame;
receiving, by the first plant station, a second data frame sent by the second plant station, and recording a receiving timestamp T sr[q] of the second data frame, wherein the second data frame comprises a sequence number q of the second data frame, a sending timestamp T mt[q] of the second data frame and a receiving timestamp T mr[p] of the first data frame, and the first data frame is adjacent to the second frame on the second plant station;
calculating, by the first plant station, a time phase difference Δs and a crystal oscillator frequency deviation Δf p between the first plant station and the second plant station according to the sending timestamp T st[p] of the first data frame, the receiving timestamp T mr[p] of the first data frame, the sending timestamp T mt[q] of the second data frame and the receiving timestamp T sr[q] of the second data frame; and
adjusting, by the first plant station, time of the first plant station according to the calculated time phase difference Δs, and adjusting a clock frequency of the first plant station according to the calculated crystal oscillator frequency deviation Δf p .
2. The method according to claim 1 , wherein the time phase difference Δs is calculated through the following formula:
Δ
s
=
(
T
mr
[
p
]
+
T
mt
[
q
]
)
-
(
T
st
[
p
]
+
T
sr
[
q
]
)
+
(
T
d
[
m
→
s
]
-
T
d
[
s
→
m
]
)
2
;
wherein, T d[m→s] is a transmission delay from the second plant station to the first plant station, and T d[s→m] is a transmission delay from the first plant station to the second plant station.
3. The method according to claim 2 , further comprising:
calculating a transmission delay T d from the first plant station to the second plant station by the first plant station, wherein the transmission delay T d is calculated through the following formula:
T
d
=
(
T
mr
[
p
]
+
T
sr
[
q
]
)
-
(
T
st
[
p
]
+
T
mt
[
q
]
)
2
;
determining whether the transmission delay T d is less than or equal to a preset transmission delay T s by the first plant station, wherein the preset transmission delay T s is calculated by the first plant station with a GPS time synchronization method; and
discarding the time phase difference Δs by the first plant station in response to determining that the transmission delay T d is greater than the preset transmission delay T s .
4. The method according to claim 1 , wherein the crystal oscillator frequency deviation Δf p is calculated through the following formula:
Δ
f
p
=
(
T
sr
[
q
]
+
T
sr
[
q
-
T
]
)
-
(
T
mt
[
q
]
-
T
mt
[
q
-
T
]
)
(
T
mt
[
q
]
-
T
mt
[
q
-
T
]
)
;
wherein T is a period for calculating the crystal oscillator frequency deviation Δf p .
5. The method according to claim 4 , further comprising: calculating a mean crystal oscillator frequency deviation Δf mean by the first plant station, wherein the mean crystal oscillator frequency deviation Δf mean is calculated through the following formula:
Δ
f
mean
=
(
∑
1
M
Δ
f
p
)
/
M
,
wherein M is a positive integer,
wherein the adjusting the clock frequency of the first plant station according to the crystal oscillator frequency deviation Δf p comprises:
adjusting the clock frequency of the first plant station by the first plant station according to the mean crystal oscillator frequency deviation Δf mean .
6. The method according to claim 1 , wherein one of the first plant station and the second plant station is a master plant station, and the other one of the first plant station and the second plant station is a slave plant station.
7. A plant station, wherein the plant station is configured to implement the synchronization method according to claim 1 .
8. A wide area system protection apparatus, comprising a first plant station and a second plant station,
wherein the first plant station is configured to: send a first data frame to the second plant station, wherein the first data frame comprises a sequence number p of the first data frame and a sending timestamp T st[q] of the first data frame;
receive a second data frame sent by the second plant station and record a receiving timestamp T sr[q] of the second data frame, wherein the second data frame comprises a sequence number q of the second data frame, a sending timestamp T mt[q] of the second data frame and a receiving timestamp T mr[p] of the first data frame, and the first data frame is adjacent to the second frame on the second plant station;
calculate a time phase difference Δs and a crystal oscillator frequency deviation Δf p between the first plant station and the second plant station according to the sending timestamp T st[p] of the first data frame, the receiving timestamp T mr[p] of the first data frame, the sending timestamp T mt[q] of the second data frame and the receiving timestamp T sr[q] of the second data frame; and
adjust time of the first plant station according to the calculated time phase difference Δs, and adjust a clock frequency of the first plant station according to the calculated crystal oscillator frequency deviation Δf p .
9. The wide area system protection apparatus according to claim 8 , wherein the time phase difference Δs is calculated through the following formula:
Δ
s
=
(
T
mr
[
p
]
+
T
mt
[
q
]
)
-
(
T
st
[
p
]
+
T
sr
[
q
]
)
+
(
T
d
[
m
→
s
]
-
T
d
[
s
→
m
]
)
2
;
wherein, T d[m→s] is a transmission delay from the second plant station to the first plant station, and T d[s→m] is a transmission delay from the first plant station to the second plant station.
10. The wide area system protection apparatus according to claim 9 , wherein the first plant station is further configured to:
calculate a transmission delay T d from the first plant station to the second plant station, wherein the transmission delay T d is calculated through the following formula:
T
d
=
(
T
mr
[
p
]
+
T
sr
[
q
]
)
-
(
T
st
[
p
]
+
T
mt
[
q
]
)
2
;
determine whether the transmission delay T d is less than or equal to a preset transmission delay T s by the first plant station, wherein the preset transmission delay T s is calculated by the first plant station with a GPS time synchronization method; and
discard the time phase difference Δs by the first plant station in response to determining that the transmission delay T d is greater than the preset transmission delay T s .
11. The wide area system protection apparatus according to claim 8 , wherein the crystal oscillator frequency deviation Δf p is calculated through the following formula:
Δ
f
p
=
(
T
sr
[
q
]
+
T
sr
[
q
-
T
]
)
-
(
T
mt
[
q
]
-
T
mt
[
q
-
T
]
)
(
T
mt
[
q
]
-
T
mt
[
q
-
T
]
)
;
wherein T is a period for calculating the crystal oscillator frequency deviation Δf p .
12. The wide area system protection apparatus according to claim 11 , wherein the first plant station is further configured to: calculate a mean crystal oscillator frequency deviation Δf mean , wherein the mean crystal oscillator frequency deviation Δf mean is calculated through the following formula:
Δ
f
mean
=
(
∑
1
M
Δ
f
p
)
/
M
,
wherein M is a positive integer,
wherein to adjust the clock frequency of the first plant station according to the crystal oscillator frequency deviation Δf p comprises:
adjust the clock frequency of the first plant station by the first plant station according to the mean crystal oscillator frequency deviation Δf mean .
13. The wide area system protection apparatus according to claim 8 , wherein one of the first plant station and the second plant station is a master plant station, and the other one of the first plant station and the second plant station is a slave plant station.
14. A non-transitory computer readable storage medium, storing a computer program, wherein the computer program, when executed by a processor, implements a synchronization method for a wide area system protection apparatus comprising a first plant station and a second plant station,
wherein the synchronization method comprises:
sending a first data frame to the second plant station by the first plant station, wherein the first data frame comprises a sequence number p of the first data frame and a sending timestamp T st[q] of the first data frame;
receiving, by the first plant station, a second data frame sent by the second plant station, and recording a receiving timestamp T sr[q] of the second data frame, wherein the second data frame comprises a sequence number q of the second data frame, a sending timestamp T mt[q] of the second data frame and a receiving timestamp T mr[p] of the first data frame, and the first data frame is adjacent to the second frame on the second plant station;
calculating, by the first plant station, a time phase difference Δs and a crystal oscillator frequency deviation Δf p between the first plant station and the second plant station according to the sending timestamp T st[p] of the first data frame, the receiving timestamp T mr[p] of the first data frame, the sending timestamp T mt[q] of the second data frame and the receiving timestamp T sr[q] of the second data frame; and
adjusting, by the first plant station, time of the first plant station according to the calculated time phase difference Δs, and adjusting a clock frequency of the first plant station according to the calculated crystal oscillator frequency deviation Δf p .
15. The non-transitory computer readable storage medium according to claim 14 , wherein the time phase difference Δs is calculated through the following formula:
Δ
s
=
(
T
mr
[
p
]
+
T
mt
[
q
]
)
-
(
T
st
[
p
]
+
T
sr
[
q
]
)
+
(
T
d
[
m
→
s
]
-
T
d
[
s
→
m
]
)
2
;
wherein, T d[m→] is a transmission delay from the second plant station to the first plant station, and T d[s→m] is a transmission delay from the first plant station to the second plant station.
16. The non-transitory computer readable storage medium according to claim 15 , wherein the method further comprises:
calculating a transmission delay T d from the first plant station to the second plant station by the first plant station, wherein the transmission delay T d is calculated through the following formula:
T
d
=
(
T
mr
[
p
]
+
T
sr
[
q
]
)
-
(
T
st
[
p
]
+
T
mt
[
q
]
)
2
;
determining whether the transmission delay T d is less than or equal to a preset transmission delay T s by the first plant station, wherein the preset transmission delay T s is calculated by the first plant station with a GPS time synchronization method; and
discarding the time phase difference Δs by the first plant station in response to determining that the transmission delay T d is greater than the preset transmission delay T s .
17. The non-transitory computer readable storage medium according to claim 16 , wherein the method further comprises: calculating a mean crystal oscillator frequency deviation Δf mean by the first plant station through the following formula:
Δ
f
mean
=
(
∑
1
M
Δ
f
p
)
/
M
,
wherein M is a positive integer,
wherein the adjusting the clock frequency of the first plant station according to the crystal oscillator frequency deviation Δf p comprises:
adjusting the clock frequency of the first plant station according to the mean crystal oscillator frequency deviation Δf mean .
18. The non-transitory computer readable storage medium according to claim 14 , wherein the crystal oscillator frequency deviation Δf p is calculated through the following formula:
Δ
f
p
=
(
T
sr
[
q
]
+
T
sr
[
q
-
T
]
)
-
(
T
mt
[
q
]
-
T
mt
[
q
-
T
]
)
(
T
mt
[
q
]
-
T
mt
[
q
-
T
]
)
;
wherein T is a period for calculating the crystal oscillator frequency deviation Δf p .
19. The non-transitory computer readable storage medium according to claim 14 , wherein one of the first plant station and the second plant station is a master plant station, and the other one of the first plant station and the second plant station is a slave plant station.