ZIV 7IRD-A - Page 75

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Chapter 6. Description of Operation of Protection Subsystem

6-35

M7IRDA2003I

7IRD-A/J/M: Distribution Protection & Control Terminal

 Start Time (Pre-Fault Time)

Pre-Fault is the storage time before the activation of the Start Function.

 Oscillographic Record Length

It’s defined as the duration time of the store window at the Fixed Time mode.

 Number of Records

The Number of Records stored in memory varies and depends on the number of channels

recorded and on the length of the fault records.

Once the recording memory is full, the Overwrite setting determines whether or not the next

event that occurs is stored over the oldest stored record (s). If the Overwrite setting has been

set to YES and as the new records vary in length, old records will get cancelled depending on

the space required by the new record.

 Record Storage Modes

Start Mode: Recorded data is stored whenever the Start Function is activated. For Fixed Time

Mode [Fixed Time (YES)] recorded data is stored for a time determined by the Record Length

Setting. For Variable Time Mode [Fixed Time (NO)] recorded data is stored while the Start

Function is activated.

Trip Mode 1: Recorded data is stored in memory only if a trip occurs. For Fixed Time Mode

[Fixed Time (YES)] recorded data is stored in memory only if a trip occurs within the time set for

the Record Length. If a trip occurs after this time has expired, no record is stored. For Variable

Time Mode [Fixed Time (NO)] recorded data whenever the Start Function is active in addition to

the pre-fault data.

Trip Mode 2: For Fixed Time Mode [Fixed Time (YES)] recorded data is stored in memory only

if a trip occurs within the time set for the Record Length. If no trip occurs within the time set for

the Record Length, only 4 cycles of recorded data will be stored after the Start Function is

activated.

For Variable Time Mode [Fixed Time (NO)] if no trip occurs while the Start Function remains

active, only 4 cycles of recorded data will be stored after the Start Function is activated. If a trip

occurs while the Start Function is active, recorded data will be stored during the whole time the

Start Function remains active in addition to the pre-fault data.

Note: For the elements in which reset time can be long, it is recommended to set Fixed Time on YES.

It is reminded that information recorded during the time set as Pre-Fault Time is always stored.

 Overwrite

If the Overwrite setting has been set to NO, no more records will be stored once the

oscillography memory is full. In that situation, set Overwrite on YES so that new records can

get stored.

If the Overwrite setting has been set to YES, once the memory is full, the next record will

replace the oldest record that is erased.