Models for hybrid positive-sequence/three-phase devices

This package contains models for hybrid positive-sequence/three-phase devices, and a set of functions used to calculate three-phase impedance matrices.

Extends from Modelica.Icons.Package (Icon for standard packages).

Name | Description |
---|---|

Line_MT | Transmission Line modeled as a PI element with a hybrid interface positive-sequence/three-phase |

Transformer_MT | Transformer modeled in a PI element with a hybrid interface positive-sequence/three-phase |

MonoTriFcn | Set of functions used in hybrid devices when finite Norton equivalent impedances are used |

TransformerFcn | Set of functions used to calculate hybrid positive-sequence/three-phase impedance matrices for transformers |

LineFcn | Set of functions used to calculate hybrid positive-sequence/three-phase impedance matrices for lines |

Transmission Line modeled as a PI element with a hybrid interface positive-sequence/three-phase

This model was design to represent a hybrid positive-sequence/three-phase power line.

The user should input the series conductance and susceptance, and half shunt susceptance (line charging). All in matrix form, since this model can be used to represent unbalanced lines. Series conductance (Gser) matrix is considered to have the following structure:

**[Gseraa**, **Gserab**, **Gserac**;

** Gserab**, **Gserbb**, **Gserbc**;

** Gserac**, **Gserbc**, **Gsercc**]

Series susceptance (Bser) matrix is considered to have the following structure:

**[Bseraa**, **Bserab**, **Bserac**;

** Bserab**, **Bserbb**, **Bserbc**;

** Bserac**, **Bserbc**, **Bsercc**]

The series admittance matrix is **Yser = Gser+jBser**. Each of the two shunt susceptance (Bsht) matrices is considered to have the following structure:

**[Bshtaa**, **Bshtab**, **Bshtac**;

** Bshtab**, **Bshtbb**, **Bshtbc**;

** Bshtac**, **Bshtbc**, **Bshtcc**]

In addition to that, the user should also state if the hybrid interface should be calculated in an approximate or exact way. If the exact way is selected, the user should also input Norton equivalent admittances for positive, negative and zero sequences calculated in the point of interconnection of the hybrid device. If approximate model is selected, these admittances are set to be zero. Based on the set of parameters selected by the user, the pi-equivalent impedance matrices are calculated and the line equation is assembled.

The positive-sequence system is connected using pin ** p**, while three-phase system is connected using pins

Extends from Branches.BaseClasses.baseLine (Partial base power line model).

Name | Description |
---|---|

Power flow data | |

S | Nominal Power [VA] |

f | System Frequency [Hz] |

Selection of model | |

ModelType | 0- Assuming that the negative and zero norton admittances are infinite (Approximation), 1- Considering that the negative and zero norton admittances finite values; |

Parameters for an 'abc'-Model | |

Gseraa | Element (1,1) in series conductance matrix [1] |

Bseraa | Element (1,1) in series susceptance matrix [1] |

Gserab | Element (1,2) in series conductance matrix [1] |

Bserab | Element (1,2) in series susceptance matrix [1] |

Gserac | Element (1,3) in series conductance matrix [1] |

Bserac | Element (1,3) in series susceptance matrix [1] |

Gserbb | Element (2,2) in series conductance matrix [1] |

Bserbb | Element (2,2) in series susceptance matrix [1] |

Gserbc | Element (2,3) in series conductance matrix [1] |

Bserbc | Element (2,3) in series susceptance matrix [1] |

Gsercc | Element (3,3) in series conductance matrix [1] |

Bsercc | Element (3,3) in series susceptance matrix [1] |

Bshtaa | Element (1,1) in shunt half susceptance matrix [1] |

Bshtab | Element (1,2) in shunt half susceptance matrix [1] |

Bshtac | Element (1,3) in shunt half susceptance matrix [1] |

Bshtbb | Element (2,2) in shunt half susceptance matrix [1] |

Bshtbc | Element (2,3) in shunt half susceptance matrix [1] |

Bshtcc | Element (3,3) in shunt half susceptance matrix [1] |

Norton equivalent admittances in terminal K - Considering the negative and zero norton admittances have finite values | |

G_0 | Zero-sequence Norton equivalent conductance [1] |

B_0 | Zero-sequence Norton equivalent susceptance [1] |

G_1 | Positive-sequence Norton equivalent conductance [1] |

B_1 | Positive-sequence Norton equivalent susceptance [1] |

G_2 | Negative-sequence Norton equivalent conductance [1] |

B_2 | Negative-sequence Norton equivalent susceptance [1] |

Name | Description |
---|---|

p | |

A | |

B | |

C |

Transformer modeled in a PI element with a hybrid interface positive-sequence/three-phase

This model was design to represent a hybrid positive-sequence/three-phase two-winding transformer.

The user should input the copper resistance **R** and leakage reactance **X** in per unit values.
The user should also input the tap value, which is the relation between primary and secondary voltage levels, but in per unit.
The user should select the transformer three-phase connection and, in addition to that, the user should also state if the hybrid interface should be calculated in an approximate or exact way.
If the exact way is selected, the user should also input Norton equivalent admittances for positive, negative and zero sequences calculated at the point of interconnection of the hybrid device.
If approximate model is selected, these admittances are set to be zero.
Based on the set of parameters selected by the user, the pi-equivalent impedance matrices are calculated and the transformer equation is assembled.
The transformer does not take into account excitation branch, since it is often neglected in transient-stability studies.

Primary side, modeled as positive-sequence equivalent, is represented by pin ** p**.
Secondary side, modeled as full three-phase system, is represented by pins

Name | Description |
---|---|

Connection | 0 Yg-Yg; 1 D-D; 2 Y-Y; 3 D-Yg; 4 Yg-D; 5 D-Y; 6 Y-D; 7 Y-Yg; 8 Yg-Y; |

Selection of model | |

ModelType | 0- Assuming that the negative and zero norton admittances are infinite (Approximation), 1- Considering that the negative and zero norton admittances finite values; |

Transformer parameters | |

tap | Nominal tap ratio (Vs/Vp) |

X | Leakage reactance [1] |

R | Windings copper resistance [1] |

Norton equivalent admittances in terminal K - Considering that the negative and zero norton admittances have finite values | |

G_0 | Zero-sequence Norton equivalent conductance [1] |

B_0 | Zero-sequence Norton equivalent susceptance [1] |

G_1 | Positive-sequence Norton equivalent conductance [1] |

B_1 | Positive-sequence Norton equivalent susceptance [1] |

G_2 | Negative-sequence Norton equivalent conductance [1] |

B_2 | Negative-sequence Norton equivalent susceptance [1] |

Name | Description |
---|---|

p | |

A | |

B | |

C |