Siemens SIPROTEC 7SJ80 User Manual

Accuracy limiting factors
Betriebs- und Nennüberstromziffer
Required minimum effective accuracy limiting
factor
but at least 20
mit
n' Minimum effective accuracy limiting factor
Ι>>
Anr
Primary pickup value of the high-current
element
Ι
pN
Primary nominal transformer current
Resulting rated accuracy limiting factor
with
K
ALF
Rated accuracy limiting factor
R
BC
Connected burden resistance (device and
cables)
R
BN
Nominal burden resistance
R
Ct
Transformer internal burden resistance
Calculation example according to IEC 60044–1
Ι
sNom
= 1 A
K
ALF
= 20
R
BC
= 0.6 Ω (device and cables)
R
Ct
= 3 Ω
R
BN
= 5 Ω (5 VA)
K
ALF
set to 10,
so that: 5P10, 5 VA
mit
Ι
sNom
= secondary transformer nominal current
D.1
Current Transformer Requirements
D.1 Accuracy limiting factors
456 SIPROTEC 4, 7SJ80, Manual
E50417-G1140-C343-A8, Edition 12.2017

Siemens SIPROTEC 7SJ80 Specifications

General

Rated Frequency	50/60 Hz
Rated Current	1 A / 5 A
Operating Temperature	-25°C to +55°C
Storage Temperature	-40°C to +70°C
Current Transformer Inputs	4
Application	Protection of feeders, motors, transformers, and generators
Rated Voltage	100-240 V AC/DC
Communication Protocols	IEC 61850, Modbus, DNP3, IEC 60870-5-103
Display	Graphical LCD
Mounting	Flush mounting
Protection Functions	Overcurrent, Earth fault
Communication Interfaces	Ethernet, RS485
Housing	Plastic
Weight	Approx. 1.5 kg