Schweitzer Engineering Laboratories SEL-321 - Relay Settings; Relay Terminal Settings; Identifier; System Data

5-2 Applications Date Code 20011026
SEL-321/321-1 Instruction Manual
System Data
The pertinent system information for this setting example is presented in Table 5.1.
Table 5.1: System Data for 230 kV Setting Example
Nominal System Voltage
Line Length
: 230 kV (132.8 kV line-to-neutral)
: 100 miles
Line 2 and Line 5 Impedances:
Positive-sequence
Zero-sequence
: Z
1
= 78.03 ∠83.97°
: Z
0
= 247.95 ∠81.46°
(primary Ω)
(primary Ω)
Line 1 and Line 4 Impedances
: Z
1
= 78.24 ∠83.72°
: Z
0
= 239.55 ∠81.56°
(primary Ω)
(primary Ω)
Line 3 and Line 6 Impedances
: Z
1
= 39.12 ∠83.72°
: Z
0
= 119.78 ∠81.56°
(primary Ω)
(primary Ω)
Source S Impedance
: Z
1
S = 17.95 ∠87.67°
: Z
0
S = 14.99 ∠80.86°
(primary Ω)
(primary Ω)
Source R Impedance
: Z
1
R = 3.80 ∠87.69°
: Z
0
R = 6.02 ∠80.90°
(primary Ω)
(primary Ω)
Current Transformer Ratio
Potential Transformer Ratio
: 1000:5
: 2000:1
Relay Settings
Fault voltages and currents in this example are derived from a fault study of the system in
Figure 5.1.
Values entered during the actual setting procedure appear in bold immediately after the = prompt
in the dashed boxes. A list of all possible relay settings appears in the settings sheet at the end of
this section. Use the settings sheet as a worksheet and record for settings.
Relay Terminal Settings
Identifier
The SEL-321 Relay has two identifier strings; the Relay Identifier (RELID) and the Terminal
Identifier (TRMID). The RELID is typically used to identify the relay or the type of protection
scheme. Typical terminal identifiers include an abbreviation of the substation name and line
terminal.
The relay tags each event report with the terminal identifier string. This allows you to
distinguish the event report as one generated for a specific breaker and substation. The date of
the last functional test may also be included for maintenance purposes.