ABB Remote I/O RIO600 Installation And Commissioning Manual page 101

1MRS757488 H
RIO600
Installation and Commissioning Manual
direction are seen in the non-operating zone. The value of Characteristic angle
depends on the network configuration.
Reliable operation requires both the operating and polarizing quantities to be above
certain minimum amplitude levels. The minimum amplitude level for the operating
quantity (current) is fixed to 50 A. The minimum amplitude level for the polarizing
quantity (voltage) is fixed to 500 V. If the amplitude level of the operating quantity or
polarizing quantity is below minimum operate voltage and current, the direction
information of the corresponding phase is set to "Unknown".
The polarizing quantity validity remains valid even if the amplitude of the polarizing
quantity falls below the minimum level of 500 V. In this case, the directional
information is provided by a special memory function for a defined time of 100 ms.
DPHPTOC is provided with a memory function to secure a reliable and correct
directional IED operation in case of a close short circuit or an earth-fault characterized
by a low voltage. At sudden loss of the polarization quantity, the angle difference is
calculated on the basis of a fictive voltage. The fictive voltage is calculated using the
polarizing quantity measured before the fault occurred.
When the voltage of one or more phases falls below minimum operate voltage of 500
V at a close fault, the corresponding phase-related fictive voltage is used to determine
the phase angle. The measured voltage is applied again when the voltage is above 500
V. The fictive voltage is also discarded if the measured voltage stays below Min
operate voltage of 500 V longer than the Voltage Mem time of 100 ms or if the fault
current disappears while the fictive voltage is in use. When the voltage is below Min
operate voltage of 500 V and the fictive voltage is unusable, the fault direction cannot
be determined.
The fictive voltage cannot be used for different reasons.
• The fictive voltage is discarded after Voltage Mem time of 100 ms
• The phase angle cannot be reliably measured before the fault situation
Level detector
The fundamental component of phase currents is compared phase-wise with the Start
value setting. If the measured value exceeds the Start value setting, the Level detector
reports the exceeding value to the phase selection logic.
The Abs Hyst Oper Qty and Abs Hyst Pol Qty setting can be used for preventing
unnecessary oscillations in START and OPERATE output if the operating and/or
polarizing quantity is slightly above or below the Start value setting. After leaving the
hysteresis area, the start condition has to be met again and if it is not sufficient, the
signal returns to the hysteresis area.
Phase selection logic
If the fault criteria is fulfilled in the Level detector and the directional calculation, the
phase selection logic detects the phase or phases in which the measured current
exceeds the setting. If the phase information matches the No. of start phase setting, the
phase selection logic activates the timer module.
Section 6
Commissioning
93