Zone Reach Setting Higher Than Minimum Load Impedance - ABB REG670 Applications Manual

Relion 670 series generator protection

Hide thumbs Also See for REG670:

Table of Contents

Impedance protection

[9] RLdRv=RLdRvFactor*RLdFw

is applicable only when the loop characteristic angle for the phase-to-

phase faults is more than three times as large as the maximum expected load-

impedance angle. More accurate calculations are necessary according to equation 77.

RFPPZx 1.6 Z

IECEQUATION2307 V2 EN

All this is applicable for all measuring zones when no Power swing detection function

ZMRPSB is activated in the IED. Use an additional safety margin of approximately

20% in cases when a ZMRPSB function is activated in the IED, refer to the description

of Power swing detection function ZMRPSB.

Zone reach setting higher than minimum load impedance

The impedance zones are enabled as soon as the (symmetrical) load impedance

crosses the vertical boundaries defined by RLdFw and RLdRv

ArgLd. So, it is necessary to consider some margin. It is recommended to set RLdFw

and RLdRv to 90% of the per-phase resistance that corresponds to maximum load.

IECEQUATION2419 V2 EN

IECEQUATION2420 V2 EN

The absolute value of the margin to the closest ArgLd line should be of the same order,

that is, at least 0.1 • Z

The load encroachment settings are related to a per-phase load impedance in a

symmetrical star-coupled representation. For symmetrical load or three-phase and

phase-to-phase faults, this corresponds to the per-phase, or positive-sequence,

impedance. For a phase-to-earth fault, it corresponds to the per-loop impedance,

including the earth return impedance.

Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062

1MRK 502 071-UEN -

(Equation 145)

or the lines defined by

(Equation 146)

(Equation 147)

Application manual

Show Quick Links

Table of Contents