ABB RELION 670 SERIES Applications Manual page 657

Line distance protection

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1MRK 506 369-UUS -

Line distance protection REL670 2.2 ANSI

Application manual

outside the limits from the start, a margin needs to be added. A typical setting is 600

The setting tMinSynch is set to limit the minimum time at which the synchronizing closing

attempt is given. The synchronizing function will not give a closing command within this

time, from when the synchronizing is started, even if a synchronizing condition is

fulfilled. A typical setting is 200 ms.

Synchrocheck settings

The OperationSC setting Off disables the synchrocheck function and sets the outputs

AUTOSYOK, MANSYOK, TSTAUTSY and TSTMANSY to low. With the setting On,

the function is in the service mode and the output signal depends on the input conditions.

VHighBusSC and VHighLineSC

The voltage level settings must be chosen in relation to the bus or line network voltage.

The threshold voltages VHighBusSC and VHighLineSC have to be set lower than the value

at which the breaker is expected to close with the synchronism check. A typical value can

be 80% of the base voltages.

The setting for voltage difference between line and bus in p.u. This setting in p.u. is

defined as (V-Bus/GblBaseSelBus) - (V-Line/GblBaseSelLine). A normal setting is

0,10-0,15 p.u.

FreqDiffM and FreqDiffA

The frequency difference level settings, FreqDiffM and FreqDiffA, shall be chosen

depending on the condition in the network. At steady conditions a low frequency

difference setting is needed, where the FreqDiffM setting is used. For autoreclosing a

bigger frequency difference setting is preferable, where the FreqDiffA setting is used. A

typical value for FreqDiffM can be10 mHz, and a typical value for FreqDiffA can be

100-200 mHz.

PhaseDiffM and PhaseDiffA

The phase angle difference level settings, PhaseDiffM and PhaseDiffA, shall also be

chosen depending on conditions in the network. The phase angle setting must be chosen

to allow closing under maximum load condition. A typical maximum value in heavy-

loaded networks can be 45 degrees, whereas in most networks the maximum occurring

angle is below 25 degrees. The PhaseDiffM setting is a limitation to PhaseDiffA setting.

Fluctuations occurring at high speed autoreclosing limit PhaseDiffA setting.