Application - ABB RELION REX640 Technical Manual

Section 4
Protection functions
4.2.6.6
492
The setting Time multiplier is used for scaling the IDMT operation and reset times.
The setting parameter Minimum operate time defines the minimum desired operation
time for IDMT. The setting is applicable only when the IDMT curves are used
The Minimum operate time setting should be used with great care
because the operation time is according to the IDMT curve but always
at least the value of the Minimum operate time setting. More
information can be found in the
protection.
Timer calculates the start duration value START_DUR, which indicates the
percentage ratio of the start situation, and the set operating time, which can be either
according to DT or IDMT. The value is available in the monitored data view.
More information can be found in the
Blocking logic
There are three operation modes in the blocking function. The operation modes are
controlled by the BLOCK input and the global setting in Configuration/System/
Blocking mode which selects the blocking mode. The BLOCK input can be controlled
by a binary input, a horizontal communication input or an internal signal of the
protection relay's program. The influence of the BLOCK signal activation is
preselected with the global setting Blocking mode.
The Blocking mode setting has three blocking methods. In the "Freeze timers" mode,
the operation timer is frozen to the prevailing value, but the OPERATE output is not
deactivated when blocking is activated. In the "Block all" mode, the whole function
is blocked and the timers are reset. In the Block OPERATE output mode, the function
operates normally but the OPERATE output is not activated.

Application

During an earth fault, HAEFPTOC calculates the maximum current for the current
feeder. The value is sent over an analog GOOSE to other protection relays of the
busbar in the substation. At the configuration level, all the values received over the
analog GOOSE are compared through the MAX function to find the maximum value.
The maximum value is sent back to HAEFPTOC as the I_REF_RES input. The
operation of HAEFPTOC is allowed in case I_REF_RES is lower than the locally
measured harmonics current. If I_REF_RES exceeds the locally measured
harmonics current, the operation of HAEFPTOC is blocked.
IDMT curves for overcurrent
General function block
1MRS759142 C
features.
REX640
Technical Manual