But in the figure we are given values in impedances, so will convert them to admittances first and then add them. Y 11 means all admittance connected at node or bus no 1. Now 4 bus system means you will need a 4X4 matrix.
Bus 3 and 2 are connected through a transmission line of impedance j0.25, you can read the rest of single line diagram in the same manner. Again we will combine these two into single impedance of j1.25. Similarly a motor (load) with an internal emf of 0.85<-45deg and an impedance of j1.15 is connected through a step down transformer of impedance j0.1, at bus no 4. You can see a Junction (a small line) between j1.15 (generator impedance) and j0.1, the junction represents here a step up transformer and j0.1 is its internal impedance, since these are in series we will combine these as j1.25 (j1.15+j0.1).
The system consists of 4 (numbered in circles) Buses, 0 bus is a ground or reference bus, a generator with an EMF of 1.25 V (per unit) and an internal impedance of j1.15 is connected to bus no 3.All values here are given in per unit, we will enlist conversion formulas for per unit system at the end) it is essential to convert all given and rated voltages, currents, impedances and admittances to be converted to per unit values before power system analysis.
Next we will teach you how to solve a Y- Bus matrix.Ĭonsider following single line diagram of a Power system:
But before you do any of that stuff you first must know how to make a Y-Bus matrix (short form for Admittance, often denoted in electrical equations as Y, inverse of impedance Z) of a given power system, involving grids, transmission lines transformers and loads. Modeling and solving of Y-bus matrices is an important part of Power system analysis and design, and is used extensively in diagnosing, solving and finding problems in power systems especially different kind of faults. Hi guys, today we are going to teach you how to model a bus admittance matrix (Y-bus) of a given power system.