SynchronousMachine

Source: GridKit/Model/PhasorDynamics/SynchronousMachine/README.md

General Synchronous Machine Model

Convention

../../../../_images/SM1.JPG

Figure 1: Synchronous Machine. Figure courtesy of PowerWorld

The following conventions are used for the d-q reference frame.

  • The q-axis leads the d-axis

  • The Rotor angle is w.r.t. to q-axis

Types

  • Classical Generator (See GenClassical)

  • Round Rotor (See GENROU)

  • Salient Rotor/Pole (See GENSAL)

  • GENPWS

  • GENTPF

  • GENTPJ

  • GENQEC

Per-Unit Basis

In relevant models, the terminal impedances are on the generator impedance base. To convert to the network base, the following must be performed.

\[\begin{aligned} Z_{term} & \mapsto Z_{term}\dfrac{S_{base,sys}}{S_{base,machine}} \end{aligned}\]

For example, say the terminal impedence is \(Z=0.05\) in per-unit on the machine’s base of \(S_{base,machine}=50\) MW, and the system base is \(S_{base,sys}=100\) MW. Then the terminal impedance on the system base is calculated as follows.

\[\begin{aligned} Z_{sys} = 0.05\dfrac{100 \text{MW}}{50 \text{MW}} = 0.1 \end{aligned}\]
Saturation

Saturation means increasingly large amounts of current are needed to increase the flux density. The Scaled Quadratic saturation model is currently implemented.

\[\begin{split}\begin{aligned} k_{sat} = \begin{cases} S_B(\psi''-S_A)^2 &\text{if } \psi''>S_A \\ 0 &\text{if } \psi''\leq S_A \end{cases} \end{aligned}\end{split}\]