Current Transformer - CT Specifications Tab

The CT Specifications tab of the CT Data dialog box is shown.

Figure 1: Specifications Tab

Option Descriptions
Option Description

CT Function

Number of current transformer ratios. You can select either Single Ratio or Multi-Ratio. If you select Multi-Ratio, you also need to enter the CT ratio that has been set.

Connected

The connection type. You can select either Wye or Delta.

CT Ratio

The ratio of rated primary to rated secondary amps of the current transformer. Specify both ratings in the form: (primary amps) / (secondary amps).

Set CT Ratio

The ratio that has been set in the case of multi-ratio current transformer.

Multi-ratio options of the CT function are shown, with a full rate of 1200/5 and set CT ratio of 600/5.

No. of CTs

The number of current transformers in the group.

One-line Graphics

To select the way the CT symbol appears in the one-line diagram. The available choices are as follows:

  • Positive Sequence
  • Zero Sequence

Show Entire Line

If you select this check box, the current transformer appears connected to the relay with a line. If it is not selected, the entire line is not shown. TO (Relay ID) appears next to the CT symbol as shown below.

The current transformer is displayed with the text "TO R-1" next to the symbol.

Allow CT to be arc flash "Main" to nearest bus

When this option is selected, the protective device connected to the CT is treated as Main in arc flash analysis.

Tip: To change polarity on a CT after it has been added to the one-line, hold the SHIFT key and drag the leader line closest to the CT downward. The CT and relay must be slightly offset for this to work.
An offset line next to the CT symbol is shown.

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