CLASSIFICATION OF BUSES
The meeting point of various components in a power system is called a bus. The bus is a conductor made of copper or aluminum having negligible resistance .At some of the buses power is being injected into the network, whereas at other buses it is being tapped by the system lods.
The matrix consisting of the self and mutual admittance of the network of the power system is called bus admittance matrix (Ybus).
Direct inspection method.
Singular transformation method.(Primitive network)
The slack bus is needed to account for transmission line losses. In a power system the total power generated will be equal to sum of power consumed by loads and losses. In a power system only the generated power and load power are specified for buses. The slack bus is assumed to generate the power required for losses. Since the losses are unknown the real and reactive power are not specified for slack bus.
Acceleration factor is used in gauss seidal method of load flow solution to increase the rate of convergence. Best value of A.F=1.6
If the reactive power constraint of a generator bus violates the specified limits then the generator is treated as load bus.