Schweitzer Engineering Laboratories SEL-311C - Settings Explanations; Identifier Labels; Current Transformer Ratios; Line Settings

9.33
Date Code 20060320 Instruction Manual SEL-311C Relay
Setting the Relay
Settings Explanations
Settings Explanations
Note that most of the settings in the settings sheets that follow include
references for additional information. The following explanations are for
settings that do not have reference information anywhere else in the
instruction manual.
Identifier Labels
Refer to Relay Settings (Serial Port Command SET and Front Panel) on
page SET.1.
The SEL-311C has two identifier labels:
➤ the Relay Identifier (RID)
➤ the Terminal Identifier (TID)
The Relay Identifier 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 report (event report, meter report, etc.) with the Relay
Identifier and Terminal Identifier. This allows you to distinguish the report as
one generated for a specific breaker and substation.
RID and TID settings may include the following characters: 0–9, A–Z, #, &,
@, -, /, ., space. These two settings cannot be made via the front-panel
interface.
Current Transformer
Ratios
Refer to Relay Settings (Serial Port Command SET and Front Panel).
Phase and polarizing current transformer ratios are set independently.
Line Settings
Refer to Relay Settings (Serial Port Command SET and Front Panel).
Line impedance settings Z1MAG, Z1ANG, Z0MAG, and Z0ANG are used in
distance relaying, fault locator (see Fault Location on page 12.5) and in
automatically making directional element settings Z2F, Z2R, Z0F, and Z0R
(see Settings Made Automatically on page 4.21). A corresponding line length
setting (LL) is also used in the fault locator.
The line impedance settings Z1MAG, Z1ANG, Z0MAG, and Z0ANG are set
in Ω secondary. To convert line impedance (Ω primary) to Ω secondary:
Ω primary • (CTR/PTR) = Ω secondary
where:
CTR = phase (IA, IB, IC) current transformer ratio
PTR = phase (VA, VB, VC) potential transformer ratio (wye-connected)
Line length setting LL is unitless and corresponds to the line impedance
settings. For example, if a particular line length is 15 miles, enter the line
impedance values (Ω secondary) and then enter the corresponding line length:
LL = 15.00 (miles)