ABB RELION 670 SERIES Applications Manual page 453

Line distance protection

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1MRK 506 369-UUS -

Line distance protection REL670 2.2 ANSI

Application manual

They must generally be blocked during normal operation and released during power

Their operation must be time delayed but shorter (with sufficient margin) than the set

time delay of normal distance protection zone 2, which is generally blocked by the

power swing.

Their resistive reach setting must secure, together with the set time delay for their

operation, that the slowest expected swings pass the impedance operate area without

initiating their operation.

Communication and tripping logic as used by the power swing distance protection zones

is schematically presented in figure 230.

The operation of the power swing zones is conditioned by the operation of Power swing

detection (ZMRPSB, 68) function. They operate in PUTT or POTT communication

scheme with corresponding distance protection zones at the remote line end. It is preferred

to use the communication channels over the optionally available "Line Data

Communication Module - LDCM" and the "Binary signal transfer to remote end"

function. It is also possible to include, in an easy way (by means of configuration

possibilities), the complete functionality into regular scheme communication logic for the

distance protection function. The communication scheme for the regular distance

protection does not operate during the power-swing conditions, because the distance

protection zones included in the scheme are normally blocked. The powerswing zones can

for this reason use the same communication facilities during the power-swing conditions.

Only one power swing zone is necessary in distance protection at each line terminal, if the

POTT communication scheme is applied. One underreaching power swing zone, which

sends the time delayed carrier signal, and one overreaching power swing zone, which

performs the local tripping condition, are necessary with PUTT schemes.

The operation of the distance protection zones with long time delay (for example, zone 3)

is in many cases not blocked by the power swing detection elements. This allows in such

cases the distance protection zone 3 (together with the full-scheme design of the distance

protection function) to be used at the same time as the overreaching power-swing zone.

Impedance protection