Current transformer supervision – Rockwell Automation 865 Differential Protection Relay User Manual

Page 97

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Supporting Functions

4-5

865-UM001A-EN-P – July 2009

Table 4.4 – Disturbance Recorder Parameters (cont.)

Parameter

Value

Unit

Description

Note

AddCh IL1,

IL2,

IL3

I’L1, I’L2, I’L3
Io1, Io2
f
IoCalc
I1, I2, I2/I1
I2/In, IoCalc
I’1, I’2, I’2/I’1
I’2/I’n, I’oCalc
IL, I’L
DO, DI
THDIL1
THDIL2
THDIL3
IL1RMS
IL2RMS
IL3RMS
ILmin,
ILmax
I’Lmin
I’Lmax
ΔIL1, ΔIL2,
ΔIL3
IL1w, IL2w,
IL3w
I’L1w, I’L2w,
I’L3w

Add one channel. Maximum
simultaneous number of channels
is 12.

Set

ClrCh –

Clear

Remove

all

channels

Set

(Ch)

List of selected channels

Set = An editable parameter (password needed)

This is the fundamental frequency rms value of one cycle updated every 10 ms.
This is the fundamental frequency rms value of one cycle updated every 20 ms.



The relay supervise the external wiring between the relay terminals
and current transformers (CT) and the CT them selves. Furthermore,
this is a safety function as well, since an open secondary of a CT,
causes dangerous voltages.

The CT supervisor function measures phase currents. If one of the
three phase currents drops below I

min

< setting, while another phase

current is exceeding the I

max

> setting, the function will issue an alarm

after the operation delay has elapsed.

Current Transformer
Supervision

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