Load Impedance Limitation, With Phase Selection With Load Encroachment, Quadrilateral Characteristic Function Activated - ABB RELION RET670 Applications Manual

Section 8
Impedance protection
8.9.3.8
8.9.3.9
344
£ ×
RFPG 0.8 Z
load min
EQUATION1721 V2 EN-US
Where:
∂ is a maximum load-impedance angle, related to the maximum load power.
To avoid load encroachment for the phase-to-phase measuring elements, the set
resistive reach of any distance protection zone must be less than 160% of the minimum
load impedance.
RFPPZx  
1.6 Z
load
EQUATION579 V3 EN-US
Equation 238 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 239.

 
 
RFPPZx 1.6 Z

load min
IECEQUATION2307 V2 EN-US
All this is applicable for all measuring zones when no Power swing detection function
ZMRPSB (78) is activated in the IED. Use an additional safety margin of
approximately 20% in cases when a ZMRPSB (78) function is activated in the IED,
refer to the description of Power swing detection function ZMRPSB (78).
Load impedance limitation, with Phase selection with load
encroachment, quadrilateral characteristic function activated
The parameters for shaping of the load encroachment characteristic are found in the
description of Phase selection with load encroachment, quadrilateral characteristic
function (FRPSPDIS ,21).
Setting of minimum operating currents
The operation of Distance protection zone, quadrilateral characteristic (ZMQPDIS, 21)
can be blocked if the magnitude of the currents is below the set value of the parameter
IMinPUPP and IMinPUPG.
é × +
2 R 1
× ¶ -
cos
ê
ë
× +
2 X 1

R1Zx
 
 
cos sin


X1Zx
1MRK 504 163-UUS A
ù
R 0
× ¶
sin
ú
û
X 0
GUID-68C89E77-77E1-47A2-A0D2-B6236CB63AB1 v1
GUID-DAFBA182-ABD1-42F7-B958-E292B8E0E161 v1
Transformer protection RET670 2.2 ANSI
Application manual
(Equation 237)
(Equation 238)
(Equation 239)