PERFORMANCE ANALYSIS OF UPFC EMBEDDED WITH THREE LEVEL CASCADED H BRIDGE INVERTER WITH SPWM AND SVPWM TECHNIQUES AND ANFIS CONTROLLER

Hybridization of the computational and control techniques has gained great importance in the last few years. One such an effort is made to combine the Fuzzy Logic Systems and the Neural Network systems. Neural Networks possess advantages in the area of Learning, Classifying and Optimization, where as Fuzzy systems are dominant in areas such as Reasoning on a degree. Both the techniques have gained individual importance in the real world simulations. Both of them are grouped in a manner where one of them is used as Pre-processor and the other as post processor. A trial and Error approach is used to solve the problem. The Performance improvement of UPFC with reference to the Transient Stability and Dynamic stability enhancement incorporating a combination of ANN and Fuzzy Logic controller called the ANFIS Controller is analysed. The UPFC is embedded with a 3 level Cascaded H Bridge Inverter. The response time taken by UPFC with ANFIS Controller is very less. Cascaded H Bridge Inverters offer high level of Voltage Support, Low Switching Stress and Good Modularity. The system response to the Reference commands or the correction commands is very faster. Apart from explaining the importance of using the ANFIS controllers this paper also takes in to consideration the advantage of using two different Pulse Width Modulation Techniques i.e., the SINUSOIDAL PWM (SPWM) and the SPACE VECTOR PWM (SVPWM) Technique. This aspect is shown by calculating the times like settling time for the transient power wave in the cases of faults like LL, and LLL and also even when the loads are changed from normal to highly Inductive and highly capacitive. The ANFIS Controller based UPFC helps the Power System Network to restore normalcy in a less time when the space vector pwm technique is used than when the sine triangle pwm technique is used. To test this aspect the UPFC is connected to the IEEE 5 bus system between the buses 3 and 4 for checking its capabilities. The faults LL and LLL are created near bus 4 in the line 3-4 and the load variations are done at bus number 4.The Simulations are carried out using MATLAB Software.