Schweitzer Engineering Laboratories SEL-421-4 - Figure 5.15 Sample TEC Command Response; Figure 5.16 Sample TEC N Command Response

5.22
SEL-421 Relay Instruction Manual Date Code 20171021
Protection Functions
Time-Error Calculation
Time-Error Command (TEC)
The TEC serial port command provides easy access to the time-error function.
See TEC on page 14.54 in the SEL-400 Series Relays Instruction Manual for
command access-level information.
Enter the TEC command to view the time-error status. A sample display is given
in Figure 5.15.
Enter the TEC command with a single numeric argument n (–30.000  n 
30.000) to preload the TECORR value. This operation does not affect the TE
analog quantity until the SEL
OGIC control equation LOADTE next asserts.
Figure 5.16 shows an example of the TEC n command in use.
Global Settings
NFREQ Nominal frequency (see Table 8.3 on page 8.2)
LOADTE Load time-error correction factor (SEL
OGIC control equation). A rising edge
will cause the relay to load the TECORR analog quantity into TE. LOADTE
has priority over STALLTE.
STALLTE Stall time-error calculation (SEL
OGIC control equation). A logical 1 will stall
(freeze) the time-error function. The TE value will not change when
STALLTE is asserted (unless LOADTE asserts).
Relay Word bit
FREQOK Frequency measurement valid. If this Relay Word bit deasserts, the TE quan-
tity is frozen (see Table 5.16).
OUTPUTS Description
Analog Quantity
TE Time-error estimate, in seconds. Positive numbers indicate that the ac clock
would be fast (ahead of the reference clock). Negative numbers indicate that
the ac clock would be slow (behind the reference clock).
Relay Word bit
PLDTE Preload Time-Error value updated. This element asserts for approximately
1.5 cycles after TECORR is changed by the TEC command or by DNP3.
Table 5.18 Time-Error Calculation Inputs and Outputs (Sheet 2 of 2)
INPUTS Description
=>TEC <Enter>
Relay 1 Date: 11/02/2004 Time: 11:25:50.460
Station A Serial Number: 0000000000
Time Error Correction Preload Value
TECORR = 0.000 s
Relay Word Elements
LOADTE = 0, STALLTE = 0, FREQOK = 1
Accumulated Time Error
TE = -7.838 s
=>
Figure 5.15 Sample TEC Command Response
==>TEC 2.25 <Enter>
Relay 1 Date: 11/02/2004 Time: 11:53:12.701
Station A Serial Number: 0000000000
Change TECORR to 2.250 s:
Are you sure (Y/N)?Y <Enter>
Figure 5.16 Sample TEC n Command Response