ABB RELION 670 SERIES REG670 - Transformer Winding, Grounded through Zig-Zag Grounding Transformer; Transformer Winding, Solidly Grounded

• magnetizing inrush currents
• overexcitation magnetizing currents
•
load tap changer
• external and internal phase faults which do not involve ground
• symmetrical overload conditions
Due to its features, REFPDIF (87N) is often used as a main protection of the
transformer winding for all faults involving ground.
7.4.2.1 Transformer winding, solidly grounded
M13048-3 v10
The most common application is on a solidly grounded transformer winding. The
connection is shown in Figure
72.
REFPDIF (87N)
I3P
I3PW1CT1
ANSI05000210_3_en.vsd
ANSI05000210 V3 EN-US
Figure 72: Connection of the low impedance Restricted earth fault function
REFPDIF (87N) for a directly (solidly) grounded transformer winding
7.4.2.2 Transformer winding, grounded through Zig-Zag grounding transformer
M13048-8 v10
A common application is for low reactance grounded transformer where the grounding
is through separate Zig-Zag grounding transformers. The fault current is then limited to
1MRK 502 071-UUS A Section 7
Differential protection
Generator protection REG670 2.2 ANSI and Injection equipment REX060, REX061, REX062 187
Application manual