This paper presents voltage stability analysis of radial distribution networks in the presence of distributed generation. The analysis is accomplished using a voltage stability index which can be evaluated at each node of the distribution system. The location of DG has the main effect voltage stability on the system. Artificial bee colony algorithm (ABC) is proposed to determine the optimal DG-unit size and location by loss sensitivity index (LSI) in order to improve the voltage stability in radial distribution system. Constant power, constant current, constant impedance and composite load modelling are considered for the purpose of voltage stability analysis.

The electric power from the system should be reliable and economical for consumer’s equipment satisfaction. An electric power system consists of many generators, transformers, transmission lines, loads, etc. For the power system network, dynamic performance and stability are important. The system is lost its stability by some disturbances i.e., load variations, generator failure, prime mover failure, transmission line outage, etc. Whenever load variations in the system, generator rotor speed will vary, means oscillations in the rotor speed, which is deviating from rated speed. The excitation system will control the generator rated line voltage. When fault occurs at any equipment in the system, the system will unstable. If fault occurs at generator, the generator oscillates. To reduce the oscillations and to make the system stable used power system stabilizers (PSS’s). Here, three types of PSS’s are used i.e., PSS1B, PSS2B, PSS4B. Comparisons of three PSS’s are on the multi machine system under some disturbance. From the observations, concluding that PSS4B is quickly control the oscillations in the physical parameters of machine in the system than other power system stabilizers.

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A new multilayer inverter topology is proposed in this study. The cascaded feature is used in this innovative topology. In addition to the isolated DC sources seen in Cascaded H- bridge. The clamping diode in Diode and the multilevel inverter (CHB-MLI) Inverter with Clamped Multilevel (DC-MLI). With these advantages, an inverter topology with 18 total component counts when coupled had been discovered. This proposed topology has the potential to generate up to According to the ratio allocated to its DC sources, there are 17 output levels. Aside from increasing the number of output voltage levels, this study has a relatively low number of component counts. The THD limit defined by IEEE standard is also a goal (i.e. 5 percent) all voltage applications under 69kV. To ensure that the suggested topology is functional, it is being simulated in Mat lab/Simulink with various modulation indexes. The amount of THD, the number of voltage outputs, and the RMS voltage are all being monitored and discussed. Finally, to assess the uniqueness of the suggested topology, a comparison study with recently disclosed topologies is being carried out.