ABB RET615 Product Manual page 17

ABB
Transformer Protection and Control
RET615
Product version: 4.0
GUID-AB31C909-F38E-4885-AFEE-E2EEE3675263 V3 EN
Figure 9. Main protection of a Yyn(d) connected power transformer and control of the HV-side circuit breaker
using a RET615 with the standard configuration D. Restricted E/F protection with a high impedance
scheme is applied on the transformer LV-side. A REF615 with the standard configuration C is used as
redundant back-up protection on the HV-side. In addition, a REF615 with the standard configuration F
is used on the LV-side to provide, besides O/C and E/F back-up protection, busbar overvoltage and
undervoltage protection. Further, the REF615 with the standard configuration F enables local/remote
control of the circuit breaker on the LV-side. The RTD inputs of the RET615 are utilized for monitoring
the oil temperature of the transformer. In addition, the mA inputs are utilized for measuring the tap-
changer position values.
1MRS756891 F
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