- 46 -
Making of I>> Phase Overcurrent Protection Settings
c.
To prevent pickup current reach the I>> threshold and cause an unwanted instantaneous
trip, I>> can be set to 7 I
rTR
practically.
4
𝐼 ≫ = 7 × 𝐼
𝑟𝑇𝑅
= 4.9 𝐼
𝑛
d.
According to the calculation above, do the following settings:
Making of Ie> Earth Overcurrent Protection Settings
e.
It is assumed that earth current up to 0.25 I
rTR
is considered to be normal. Over this
value, the primary circuit will be broken in 1.0 s. Presuming those, I
e
> threshold value is
calculated as follows:
𝐼
𝑒
> = (15 𝐴 60 𝐴
⁄
)𝐼
𝑒𝑛
= 0.25 𝐼
𝑒𝑛
f.
According to the calculation above, do the following settings:
Making of Ie>> Earth Overcurrent Protection Settings
g.
Presuming earth current equal to or higher than 0.75 I
rTR
is considered as earth fault,
I
e
>> threshold value is calculated as below:
𝐼
𝑒
≫ = (45 𝐴 60 𝐴
⁄
)𝐼
𝑒𝑛
= 0.75 𝐼
𝑒𝑛
h.
According to the calculation above, do the following settings:
6.
All needed settings are done by now. Check all the settings and note them. CPM 310 G is ready
for commissioning. □
4
Actual pick-up current values can be checked on
MENU
Measurements
Max RMS Currents
page.
Main Screen » Set » I>>
Main Screen » Set » I
e
>
Main Screen » Set » I
e
>>
Summary of Contents for CPM 310 G
Page 1: ...CPM 310 G Digital Overcurrent Protection Relay User Application Manual vEN 2016 03...
Page 2: ...2...
Page 6: ...6 ABOUT DEMA...
Page 11: ...11 INTRODUCTION...
Page 32: ...32 PACKING LABELING INFORMATION...
Page 34: ...34 OPERATING MANUAL...
Page 53: ...53 RELAY MENUS MANUAL...
Page 55: ...55 The Menu Tree...
Page 56: ...56...
Page 57: ...57...
Page 58: ...58...
Page 59: ...59...
Page 60: ...60...
Page 61: ...61...
Page 128: ...128 DIGICONNECT PC PROGRAM MANUAL...
Page 189: ...189 APPLICATION DIAGRAMS...
Page 191: ...191 Sample Power Transformer Protection Application Diagram...
Page 193: ...193 FUNDAMENTAL CABLING DIAGRAM...
Page 203: ...203 APPLICATION DIAGRAM NO 10 RS485 Cabling...
Page 204: ...204 TECHNICAL DATA...
Page 220: ...220 GLOSSARY...