Schweitzer Engineering Laboratories SEL-700G Series, Инструкция по эксплуатации

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4.86
SEL-700G Relay Instruction Manual Date Code 20170814
Protection and Logic Functions
Group Settings (SET Command)
Some indicators that the generator is removed from service include:
➤
Low terminal voltage
➤
Field circuit breaker is open
➤
No phase current
Set 27V1X1P pickup (see Table 4.43 for the undervoltage element settings) to
a low value to ensure that there is no voltage at the generator terminals. Use
the SEL
OGIC
control equation INADTC to indicate open generator breaker
and/or field breaker. The SEL-700G uses Relay Word bit 50LX as a generator
current detector. See Pole Open Logic on page 4.185 for details.
Settings GENDEPU and GENDEDO provide time-delay pickup and dropout
to the logic. The time-delay pickup adds an arming delay to prevent the
scheme from arming prematurely when the generator is removed from service.
The dropout time ensures that the scheme trips when the relay detects current
during an inadvertent energization.
See Figure 4.52 for the logic diagram of the scheme. The Relay Word bit
INADT is configured to shut down the generator in the factory-default logic.
Refer to Trip/Close Logic Settings on page 4.186 for details. You must change
the setting if your application requires a different action.
Figure 4.52 Inadvertent Energization Logic Diagram
Following are some setting guidelines for the inadvertent energization logic:
➤
Set 50LXP (see Table 4.52) equal to 0.25 A secondary, for most
applications, to provide maximum current sensitivity. A higher
pickup setting may be necessary in special cases (static start of a
gas turbine, for example) to prevent assertion of Relay Word
50LX by the starting current.
➤
The default for the torque control setting INADTC is 3POX. The
Relay Word bit 3POX logic includes generator current and main
breaker auxiliary contact input (see Figure 4.124). If necessary,
change the setting INADTC to suit your application.
Table 4.16 Inadvertent Energization Protection Settings
Setting Prompt Setting Range
Setting Name :=
Factory Default
INADV ENRG EN Y, N EINAD := N
GEN DE-ENRG PU 0.00-100.00 s GENDEPU := 2
GEN DE-ENRG DO 0.00-100.00 s GENDEDO := 1
INADV ENRG PU 0.00-10.00 s INADPU := 0.25
INADV ENRG DO 0.00-10.00 s INADDO := 0.13
INADV TRQCTRL SEL
OGIC
INADTC := 3POX
GENDEPU
GENDEDO
INADPU
INADDO
Relay
Word
Bits
Settings
Relay
Word
Bits
27V1X1
NOTE:
Because this protection
scheme is disabled when generator
terminal voltage returns to near
normal, it does not provide protection
for generator energization that
results from breaker flashover prior to
synchronizing.