Equipment Protection, Capacitors; Power Supply Quality; High Impedance Grounded Systems; The Following Settings Can Be Done For The Two Step Overvoltage Protection - ABB Relion 670 Series Applications Manual

Section 8
Voltage protection
8.2.3.2

Equipment protection, capacitors

High voltage will deteriorate the dielectricum and the insulation. The setting has to be well above
the highest occurring "normal" voltage and well below the highest acceptable voltage for the
capacitor.
8.2.3.3

Power supply quality

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.
8.2.3.4

High impedance grounded systems

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.
8.2.3.5

The following settings can be done for the two step overvoltage protection

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
gets lower than the set percentage of
the IED automatically divides set value for
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-earth over voltage is automatically divided by sqrt3. This
means operation for phase-to-ground voltage over:
>
V (%)
EQUATION1713 V2 EN-US
and operation for phase-to-phase voltage over:
Vpickup
EQUATION1992-ANSI V1 EN-US
The below described setting parameters are identical for the two steps (n = 1 or 2). Therefore the
setting parameters are described only once.
Characteristicn : This parameter gives the type of time delay to be used. The setting can be
Definite time , Inverse Curve A , Inverse Curve B , Inverse Curve C or I/Prog. inv. curve . The choice is
highly dependent of the protection application.
206
×
VBase kV ( ) / 3
> ×
(%) VBase(kV)
ConnType . The function will operate if the voltage
VBase . When ConnType is set to PhN DFT or PhN RMS then
VBase by √3. When ConnType is set to PhPh DFT or PhPh
1MRK 511 358-UUS A
M13852-13 v1
M13852-16 v1
M13852-19 v5
M13852-22 v8
(Equation 95)
(Equation 96)
Application manual