BECKWITH ELECTRIC Syncrocloser M-3410A, Instruction Book

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M-3410A Instruction Book
3–38
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#1
Pickup:
Delay:
100.0 %
1 Cycle
150.0 %
8160 Cycles
(59) Overvoltage X
Outputs Blocking Inputs
2 1
2 1 FL
Outputs Blocking Inputs
2 1
2 1 FL
Pickup:
Delay:
100.0 %
1 Cycle
150.0 %
8160 Cycles
#2
Figure 3-43 M-3810A IPScom
®
for Windows™ (59) Phase Overvoltage Setup Dialog Screen
Path : Relay/Setup/Setpoints/59 Phase Overvoltage
COMMAND BUTTONS
Save Saves all entered information to the control.
Cancel Returns you to the previous window; any changes to displayed information are lost.
■
NOTE : Pickup percentage is based on Nominal Voltage.
59 Phase Overvoltage, 3-Phase
Generator Protection
: The RMS Overvoltage
function (59) may be used to provide overvoltage
protection for the generator. The relay provides
overvoltage protection functions with two voltage
levels and two definite-time setpoints, either of
which can be programmed to trip the unit or send an
alarm. This is a true 3-phase function in that each
phase has an independent timing element.
Magnitude measurement depends on the 59/27
Magnitude Select setting (See Section 3.1, Relay
Configuration, Relay Setup). When the RMS option
is selected, the magnitude calculation is accurate
over a wide frequency range (10 to 80 Hz) and an
additional time delay of 20 cycles (beyond the set
delay) may occur. If DFT is selected, the magnitude
calculation is accurate near 50 or 60 Hz, and the
timer accuracy is
&
2 cycles. RMS selection is
recommended for generator protection applications,
as RMS calculations are accurate over a wide
frequency range. Generator capacity is generally
105% of rated voltage.
Intertie Protection : Voltage is commonly suggested
as an efficient means to protect against islanding.
Notably, unless the Dispersed Generation (DG)
includes very high-speed generator excitation
responses, the island case where load is less than
generation will result in a rapid rise of voltage.
Except for those systems prone to ferroresonance,
the voltage waveform will remain essentially
sinusoidal, making the use of DFT (RMS value of
the fundamental frequency component) for the
measurement.
The first setpoint (with a short time delay) is typically
set up at 150% of the nominal voltage, and the
second setpoint (with a long time delay) be set at
106 to 110% of the nominal voltage to prevent
nuisance trips.