Transformer Module - Toshiba GRL100-701B Instruction Manual

3.1.2

Transformer Module

The transformer module (VCT module) provides isolation between the internal and external AC
circuits through an auxiliary transformer and transforms the magnitude of AC input signals to
suit the electronic circuits. The AC input signals are as follows:
• three-phase currents (I a , I b and I c )
• residual current (3I o )
• residual current of parallel line (3I om )
• three-phase voltages (V a , V b and V c )
• autoreclose reference voltage (V ref1 )
• autoreclose reference voltage (V ref2 )
Figure 3.1.2.1 shows a block diagram of the transformer module. There are 5 auxiliary CTs
mounted in the transformer module, and an additional 5 auxiliary VTs. (The reference between
terminal numbers and AC input signals is given in Table 3.2.1.1.)
V ref1 and V ref2 are the busbar or line voltages necessary for the voltage and synchronism check
for the autoreclose.
The transformer module is also provided with an IRIG-B port. This port collects the serial
IRIG-B format data from the external clock for synchronization of the relay calendar clock. The
IRIG-B port is insulated from the external circuit by a photo-coupler. A BNC connector is used
as the input connector.
Transformer module
I a
I b
I c
3I o
3I om
V a
V b
V c
V ref1
V ref2
IRIG-B port
External
clock
BNC connector
Figure 3.1.2.1 Transformer Module
 161 
6 F 2 S 0 8 5 0
Signal
processing
module