Independent R.o.c.o.f Protection Logic; Application Notes; Setting Guidelines; Figure 129: Independent Rate Of Change Of Frequency Logic (Single Stage) - GE MiCOM P40 Agile Technical Manual

Feeder management ied
Hide thumbs Also See for MiCOM P40 Agile:
Table of Contents

Advertisement

P14x
5.2

INDEPENDENT R.O.C.O.F PROTECTION LOGIC

Frequency
df/dt
V
determination
df /dt Avg .Cycles
df/dt smooth fct
df /dt+t 1 Set
Stage 1
Enabled
df /dt+t 1 Status
Positive
Both
Negative
Disabled
V<B Status
Enabled
UV Block
Stg1 Block
Adv Freq Inh
Freq Not Found
Freq High
Freq Low
V00870

Figure 129: Independent rate of change of frequency logic (single stage)

5.3

APPLICATION NOTES

5.3.1

SETTING GUIDELINES

Considerable care should be taken when setting this element because it is not supervised by a frequency setting.
Setting of the time delay or increasing the number of df/dt averaging cycles will improve stability but this is traded
against reduced tripping times.
It is likely that this element would be used in conjunction with other frequency based protection elements to
provide a scheme that accounts for severe frequency fluctuations. An example scheme is shown below:
Frequency "f+t [81U/81O]" Elements
Frequency
Stage
Setting (Hz)
1
49
2
48.6
3
48.2
4
47.8
5
-
P14xEd1-TM-EN-1
Smoothing
filter*
-1
X
1
1
1
1
1
*Note: The smoothing filter setting only applies when the magnitude of the tracking voltage or current is changed . If
there is no change , the factor is set to 1.
Time Setting (Sec.)
20
20
10
10
-
Chapter 11 - Frequency Protection Functions
&
1
&
Frequency Supervised Rate of Change of Frequency "f+df/dt
[81RF]" Elements
Frequency Setting
Rate of Change of Frequency Setting (Hz/
(Hz)
49.2
1.0
48.8
1.0
48.4
1.0
48.0
1.0
-
-
Stg1 df /dt+t Sta
Stg1 df /dt+t Trp
df/dt+t 1 Time
Sec.)
243

Hide quick links:

Advertisement

Table of Contents
loading

Table of Contents