Toshiba GR200 Series Instruction Manual page 274

Setting of VCT
4.2.5
Input sources are transformed with various VTs and CTs so that the ratio shall be set in each
zone with settings in each CH.
VT
(i)
VT ratio
When the VT is applied, a ratio of the primary voltage to the secondary voltage has to be set.
The VCT will have three-phase voltage of each zone; hence, the user shall set the ratio for the
setting [VT_Z*_Ratio]†. For example, the user can set '3636' for the [VT_Z*_Ratio] when the
primary is 400kV and the secondary is 110V (i.e., 400kV/110V=3636). The VCT channel is
discussed in the preceding sections.
†Note: Term 'Z*' represents one of six zones (i.e., ZA, ZB, ZC, ZD, ZE, and ZF).
CT
(ii)
CT ratio
When the CT is applied, a ratio in three-phases of the primary current to the secondary current
has to be set. For example, the user can set '4000' for the [CT_CH*_Ratio]† when the primary
to the secondary is 4000/1.
†Note: Term 'CH*' represents one of 24 CHs (i.e., CH1, CH2, CH3 ..., CH24).
Rated current (=CT secondary value)
The rated current of the auxiliary CT on the VCT module is pre-configured when the IED is
shipped from the manufacturer; the value of the rated current is set uniquely either 1A or 5A
for all auxiliary CTs. However, the user can independently change the value of the rated
current from the pre-configured rated current. It is important that the user has to carry out
and confirm that both rated current setting (Step1) and jumper switch (Step2) have been made
correctly.
Step 1: Setting
Set the [CT_CH*_Rating]=5A when changing from 1A to 5A is required. The pre-
configured rated current is identical to the AC rating determined in accordance with the
order from the customer. Thereby, the user shall be careful not to change other setting
items, which the user does not wish to alter from the original requirements specified in
the customer order.
Step 2: Jumper switch
Each of the auxiliary CTs has a Jumper; hence, the user has to have the jumper setting
for changing the rated current. The user can select the rated current by following the
handlings below with reference to Figure 4.2-7:
Open the IED front panel.
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6F2S1931 (0.20)
Centralized GRB200
(Soft: 030, 031, 032, 033, 034)