GE Multilin G650, Manual, Page: 153 / 639

5-10 G650 Generator Protection & Control System GEK-113285A
5.2 PRODUCT SETUP 5 SETTINGS
5
5.2.4.2 OSCILLOGRAPHY SETTINGS
These settings (
“Setpoint > Product Setup > Oscillography”
) are described in Table 5–11:
Table 5–11: OSCILLOGRAPHY SETTINGS
Function Permission (Function):
Enabling this setting allows to create an oscillography record when the “
TRIGGER
OSCILLO
” signal is activated.
Trigger Position:
This setting defines the prefault data (in percentage) stored every time a new oscillo is
produced.
Sampling Rate:
This setting defines the sampling rate of the oscillography capture. Please see the
example below.
Maximum Number of Oscillos (Max. Number Osc.):
1 to 20 oscillography records can be selected. The capacity of each record is = 1Mbyte
/ Max. Number Osc. This capacity is divided in 38 bytes (9 measurements * 4 bytes/
measu 2 digital bytes) per stored sample. Please refer to example below.
Automatic Overwrite:
This setting allows chained oscillographies during the fault (TRIGGER OSCILLO signal
activated). The maximum allowed value to be stored as a chained oscillography is 1
Mbyte. In this case, even if the trip continues during a time longer than the associated
1 Mbyte of memory, the relay will stop storing the oscillography in RAM memory until
the complete record has been saved in non-volatile memory. The oscillography
module will be reset once the data has been completely stored in Flash memory and
the TRIGGER OSCILLO state is deactivated.
Snapshot Events:
This setting enables or disables snapshot event generation for the oscillography
element.
EXAMPLE
For a Max. Number Osc. of 4, each record will store 1Mbyte / 4 = 262144 bytes.
Therefore, the number of samples per oscillography record is 262144 bytes / 38 bytes = 6898 samples per stored oscillo.
If we set the relay to 3600 Hz as sampling rate , each record will store up to:
• 6898 / 72 = 95.78 signal cycles at 50 Hz as nominal frequency
• 6898 / 60 = 114.93 signal cycles at 60 Hz as nominal frequency
This value expressed in terms of time would be:
For 50 Hz: 95.78 cycles x 20 ms/cycle =1.915 seconds.
For 60 Hz: 114.93 cycles x 16.67 ms/cycle =1.915 seconds.
SETPOINT > PRODUCT SETUP > OSCILLOGRAPHY
Setting Description Name Default Value Step Range
Function Permission Function ENABLED N/A [DISABLED – ENABLED]
Prefault Trigger Position 30 1% [5 : 95]
Sampling rate Sampling Rate 3600 Hz [225-450-900-1800-3600]
Maximum number of oscillos Max. Number Osc. 4 1 oscillo [1 : 20]
Automatic oscillography overwrite Automatic Overwrite DISABLED N/A [DISABLED – ENABLED]
Snapshot Event generation Snapshot Events ENABLED N/A [DISABLED – ENABLED]