Introduction; Principle Of Operation; Directional Impedance Element For Mho Characteristic Zdmrdir (21D) - ABB Relion 670 Series Technical Reference Manual

1MRK505222-UUS C
6.6.1
6.6.2
6.6.2.1
Technical reference manual
Function description
Additional distance protection
directional function for earth faults

Introduction

The phase-to-ground impedance elements can be optionally supervised by a phase
unselective directional function based on symmetrical components.

Principle of operation

Directional impedance element for mho characteristic ZDMRDIR (21D)

The evaluation of the directionality takes place in Directional impedance element for
mho characteristic (ZDMRDIR ,21D). Equation
that the fault is in the forward direction for phase-to-ground fault and phase-to-phase
fault respectively.
×
0.85 V A
- <
AngDir Ang
EQUATION1618 V1 EN
×
0.85 V AB
- <
AngDir Ang
EQUATION1620 V1 EN
Where:
AngDir Setting for the lower boundary of the forward directional characteristic, by default set to
15 (= -15 degrees)
AngNegRes Setting for the upper boundary of the forward directional characteristic, by default set to
115 degrees, see figure
V1A Positive sequence phase voltage in phase A
V1AM Positive sequence memorized phase voltage in phase A
IA Phase current in phase A
V1AB Voltage difference between phase A and B (B lagging A)
V1ABM Memorized voltage difference between phase A and B (B lagging A)
IAB Current difference between phase A and B (B lagging A)
IEC 61850
identification
ZDARDIR
50
+ ×
1 0.15 V AM 1
<
AngNeg
IA
+ ×
1 0.15 V ABM 1
<
AngNeg
IAB
142 for mho characteristics.
Section 6
Impedance protection
IEC 60617 ANSI/IEEE C37.2
identification device number
-
S00346 V1 EN
and equation 51 are used to classify
Re s
Re s
(Equation 50)
(Equation 51)
277