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Winter 2014 |
Report #001 – 01/08 /14 |
Jiying Dong |
I. Plan for next week (***, **, *: order of priority)
40%: Find out un-normal data’s feature,and according the feature to find correct data structure.
o static the rate of available packets;
o static the rate of resend packets;
o static the stability of the packets sent from the substation.
· 40%: find out the correct data structure to analyze heart beat data packets
o analyze heart beat data packets’s sending time span , find the network’s status;
· 20%: Read the code of sniff.
o to learn how to capture network data packets, and the program’s overall architecture.
II. Tasks achieved this week (***, **, *: order of priority)
· 50%: Read real-time dynamic monitoring system of power system -Part2:
Protocols for data transfering.(national standards)
o Understand data structure that transfered between the substation and the main station;
o Understand data flow direction between the substation and the main station;
· 40%: Read real-time dynamic monitoring system of power system -Q_GDW_ 131_2006 (enterprise standards)
o Understand data structure that transfered between the substation and the main station;
o Understand data flow direction between the substation and the main station.
· 10%:
o Read the code of pmu_sniff to learn how to capture network data packets.
III. Dr. Yan's feedback last week
· None
IV. Reports
1. data structure that transfered between the substation and the main station(enterprise standards):
a.The bytes definition of data frame :
The last two bytes of the data frame are CRC confirmation number.We check the confirmation number to make sure of the correctness of the data frame.
The fifth filed of the data frame is a status word .The status word occupys two bytes of the data frame. The bit 15 of status word indicates the correctness of the data frame.
The bits 05~04 of status word indicate the GPS time tag status.
b.The bytes definition of hart beat frame:
When the fifth filed’s bits 15~13 are a sequence of 010,the frame is a heart beat frame.
Normally the heart beat frame is sent from the main station ,the substation will post back the frame immediately when receive it. If we can’t find the heart beat frame of the network packets in a setted time interval,we would judge the network is un-normal.
2. The difference between national standards and enterprise standards:
a.
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Standard name Data frame |
Field -IDCODE |
Field -FRACSEC |
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enterprise standards |
Without this field |
Bit 31:leap second ,1 indicate leap second,0 normal. Bit 30:leap second foreshow,1 indicate the next second is leap second,0 normal. Bit 29~24 :keep for use. Bit 23~00: second divided number. |
|
national standards |
Yes ,occupy 8bytes |
Bit 31:keep for use. Bit 30:leap second direction,1 indicate minus ,0 add Bit 29:leap second happen flag Bit 28:leap second foreshow,1 indicate the next second is leap second,0 normal. Bits 27~24: time quality,0000 indicate clock is normal. Bits 23~00:second divided number.
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b.
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Standard name Command frame |
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enterprise standards |
SYNC|FRAMESIZE|SOC|IDCODE|CMD|CRC16 2 | 2 | 4 | 8 | 2 | 2 |
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national standards |
SYNC|FRAMESIZE|IDCODE|SOC|CMD|CRC16 2 | 2 | 8 | 4 | 2 | 2 |
V. Mile-Stone:
· count the abnormal data packets that transfered from substation to main station .
· Find out the network work status according data packets.