electricpy.fault.ct_cclass¶

electricpy.fault.ct_cclass(XoR, Imag, Irated, CTR, Rb, Xb, remnance=0, sat_crit=20)[source]¶

Electrical Current Transformer (CT) C-Class Function.

A function to determine the C-Class rated voltage for a CT. The formula shown below demonstrates the standard formula which is normally used to evaluate the saturation criteria. Worth noting here, is the fact that \(V_{rated}\) is the CT C-Class.

\[\text{Saturation Criteria}=\frac{(1+\frac{X}{R})\cdot \frac{|I_{mag}|}{I_{rated}\cdot CTR}\cdot\frac{\left| R_{burden}+j\cdot X_{burden}\right|\cdot100}{V_{rated}}} {1-remnance}\]

For the purposes of this function, the above formula is applied as follows to evaluate the CT C-Class such as to satisfy the saturation criteria defined.

\[\text{CT C-Class}=\frac{(1+\frac{X}{R})\cdot \frac{|I_{mag}|}{I_{rated}\cdot CTR}\cdot\frac{ \left|R_{burden}+j\cdot X_{burden}\right|\cdot100} {\text{Saturation Criteria (i.e., 20)}}}{1-remnance}\]

Parameters:¶

XoR : float¶

The X-over-R ratio of the system.

Imag : float¶

The (maximum) current magnitude to use for calculation, typically the fault current.

Irated : float¶

The rated secondary current for the CT.

CTR : float¶

The CT Ratio (primary/secondary, N) to be used.

Rb : float¶

The total burden resistance in ohms.

Xb : float¶

The total burden reactance in ohms.

remnance : float, optional¶

The system flux remnance, default=0.

sat_crit : float, optional¶

The saturation criteria which must be satisfied, typically such that CT saturation will not occur, default=20.

Returns:¶

c_class – The calculated C-Class rated voltage.

Return type:¶

float