Table of Contents
Advertisement
Transmission Format
The data transmission format depends on the communication mode.
Figures N-1 and N-2 show the data transmission format that applies to the data transmission
between terminals of the transmission lines by the relay. The individual parts of the transmission
format are described below.
(1) Frame header
A signal indicating the head of a frame.
(2) Current data
12 bit data (incl. one sign bit) indicating the current value of sampling of each phase.
(3) SA flag and control data
Device data (CB, DS) and control data necessary for the protective function are transmitted
by sub-commutation. Sub-commutation is used for signals that may be transmitted at low
speed, and has the meaning that 1-bit information is different from frame to frame.
Frames are identified by the SA flag, which is also transmitted by sub-commutation. It
detects the signal pattern of 00001 and identifies a frame number. One cycle of frame
numbers covers 12 frames.
(4) SP flag and time data
The SP flag and time data for sampling time synchronization are transmitted by
sub-commutation. Sub-commutation detects the signal pattern of 00001 and identifies a
frame number.
The time data for sampling time synchronization has 16 bits.
(5) CRC (Cyclic Redundancy Check) data
CRC data is added to check transmitting data for transmission errors.
Data without the frame header is divided by a polynomial and the resultant remainder is
transmitted as the CRC data.
On the receiving side, the CRC data is subtracted from the transmitted data, the result divided
by the same polynomial, and the remainder checked for 0.
Polynomial: X
(6) User configurable data
Number of user configurable data depends on the communication mode and whether a
function is used or not. The transmission data and user configurable data is shown in Table
N-1 and Figures N-1 and N-2.
16
+ X
12
+ X
5
+ 1
418
6 F 2 S 0 8 5 0
Hide quick links:
Advertisement
Table of Contents
