Observability

class popo.estimation.Observability(buses, required, available)

Bases: object

Whether a measurement set has enough equations to determine the state.

Weighted least squares needs at least one equation per unknown: a voltage magnitude and angle at every bus, less the reference angle, 2n - 1. Each real or pseudo power measurement contributes one equation, and each bus known to inject nothing contributes two. Enough equations is necessary, not sufficient: they must also reach every part of the network, which a count cannot see, so a set that passes here can still fail to solve.

Variables:

• buses – Buses in the network.

• required – Equations needed, 2 * buses - 1.

• available – Equations the measurement set provides.

property sufficient: bool

Whether there are at least as many equations as unknowns.

property shortfall: int

Equations missing, 0 when the count is sufficient.