Impedance and Admittance Methods

CommonOPF exports edge impedance and admittance methods to support building optimal power flow models (see Edge Impedance and Admittance). Internally, the exported methods are supported by methods that dispatch on the edge types:

subtypes(CommonOPF.AbstractEdge)

3-element Vector{Any}:
 CommonOPF.Conductor
 CommonOPF.Transformer
 CommonOPF.VoltageRegulator

The internal methods began with those for Conductor:

resistance_per_length(c::Conductor, phase_type::Type{T}) where {T <: Phases}

if ismissing(c.phases)  # single phase
    return c.r1
end
return c.rmatrix

Note that conductor resistance and reactance values are expected in per unit length values (since per unit length values are what one finds in engineering data sources).

Admittance values are derived using the inverse of the impedances:

conductance_per_length(c::Conductor, phase_type::Type{T}) where {T <: Phases}

if phase_type == SinglePhase
    return c.r1 / (c.length^2 * (c.r1^2 + c.x1^2))
end
return real(inverse_matrix_with_zeros(c.rmatrix + im * c.xmatrix)) / c.length^2