Licht MFC-202/P, Техническое руководство, Страница: 3 / 23

Licht
http://www.licht-labs.com
info@licht-labs.com
Rev. A2 (30–05–12) MFC-202/P Technical Manual 2
1 Introduction
The MFC-202/P controller was developed by Licht for the paralellism supervision and
control of 3-phase power transformers and 3-phase groups of monophase transformers.
The MFC-202/P features 10 relays for electromechanic logic, one RS485 interface for
supervision and control and one optional current output for position retransmission.
The parallelism control is implemented according to the master-follower principle, under
which all tap changer positions are kept synchronized. For parallel control to be success-
ful under this scenario, we admit that all involved transformers have identical nominal
currents, number of taps and voltage delta per tap. Each tap changer’s position is read
directly from its potentiometric sensor or indirectly either via a current loop (typically 4-
20 mA) or BCD contacts, according to the client’s specifications. During parallel control,
the Master tap changer’s position is compared to its Followers’, and tap changer pulses
are issued to the Follower tap changers whose positions don’t match their Master’s.
In the MFC-202/P architecture, each controller is responsible for a 3-phase transformer
or a monophase transformer, and is interconnected with other MFC-202/P using a RS485
bus arrangement. MODBUS or DNP3 functionality is provided on a second dedicated
RS485 port, which does not require additional hardware.
Figure 1.1 MFC-202/P controller