Schweitzer Engineering Laboratories SEL-701 - General Data; Identifier Settings; Table 4.1; CT Configuration Settings

701 Motor Protection Relay Date Code 20010719
Settings Calculation
General Data
4.4
General Data
Identifier Settings
All models of the SEL-701 Relay have the following identifier settings:
Table 4.1 Iden tifier Settings
The SEL-701 Relay prints the Relay and Terminal Identifier strings at the top of
responses to serial port commands to identify messages from individual relays. Enter
up to 20 characters, include capital letters A–Z, numbers 0–9, periods (.), dashes (-),
and spaces. Suggested identifiers include the location, process, circuit, size, or
equipment number of the protected motor.
Current Transformer (CT) Configuration Settings
Table 4.2 CT C onfiguration Set tings
The CT ratio and secondary rating settings configure the relay to accurately scale
measured values and report the primary quantities. Calculate the phase and neutral CT
ratios by dividing the primary rating by the secondary rating.
EXAMPLE 4.1 Phase CT Ratio Setting Calculation
Consider an application where the phase CT ratios are 600:5.
Set CTR = 600/5 = 120.
Set ITAP = 5 A.
Select phase current transformers for your application so that the primary current
rating is equal to or greater than the motor full load current. Full load current should
not be less than half the CT primary current rating. See Example 4.1.
Table 4.1 Identifier Settings
Setting Prompt Setting Range Setting Name = Factory Default
Relay Identifier 20 Characters RID = SEL-701
Terminal Identifier 20 Characters TID = MOTOR RELAY
Table 4.2 CT Configuration Settings
Setting Prompt Setting Range
Setting Name =
Factory Default
Phase (IA, IB, IC) CT Ratio 1–6000 CTR = 100
Phase CT Secondary Rating 1, 5 A ITAP = 5
Neutral (IN) CT Ratio 1–6000 CTRN = 100
Neutral CT Secondary Rating 1, 5 A INTAP = 5