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10.2.3.3
Power supply quality
M13852-16 v1
The setting has to be well above the highest occurring "normal" voltage and below the
highest acceptable voltage, due to regulation, good practice or other agreements.
10.2.3.4
High impedance grounded systems
M13852-19 v6
In high impedance grounded systems, ground-faults cause a voltage increase in the
non-faulty phases. Two step overvoltage protection (OV2PTOV, 59) is used to detect
such faults. The setting must be above the highest occurring "normal" voltage and
below the lowest occurring voltage during faults. A metallic single-phase ground-fault
causes the non-faulted phase voltages to increase a factor of √3.
10.2.3.5
The following settings can be done for the two step overvoltage
protection
M13852-22 v10
ConnType
: Sets whether the measurement shall be phase-to-ground fundamental value,
phase-to-phase fundamental value, phase-to-ground RMS value or phase-to-phase
RMS value.
Operation
:
Disabled
/
Enabled
.
VBase
(given in
GlobalBaseSel
): Base voltage phase to phase in primary kV. This
voltage is used as reference for voltage setting. OV2PTOV (59) measures selectively
phase-to-ground voltages, or phase-to-phase voltage chosen by the setting
ConnType
.
The function will operate if the voltage gets lower than the set percentage of
VBase
.
When
ConnType
is set to
PhN DFT
or
PhN RMS
then the IED automatically divides set
value for
VBase
by √3. When
ConnType
is set to
PhPh DFT
or
PhPh RMS
then set
value for
VBase
is used. Therefore, always set
VBase
as rated primary phase-to-phase
ground voltage of the protected object. If phase to neutral (PhN) measurement is
selected as setting, the operation of phase-to-ground over voltage is automatically
divided by sqrt3. This means operation for phase-to-ground voltage over:
(%)
(
) / 3
V
VBase kV
>
×
EQUATION1713 V2 EN-US
(Equation 234)
and operation for phase-to-phase voltage over:
Vpickup
(%) VBase(kV)
>
×
EQUATION1992-ANSI V1 EN-US
(Equation 235)
The below described setting parameters are identical for the two steps (n = 1 or 2).
Therefore the setting parameters are described only once.
1MRK 502 071-UUS A
Section 10
Voltage protection
Generator protection REG670 2.2 ANSI and Injection equipment REX060, REX061, REX062
443
Application manual
Summary of Contents for RELION 670 SERIES REG670
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