Flexible AC transmission system (FACTS) is a technology, which is based on power electronic devices, used to enhance the existing transmission capabilities in order to make the transmission system flexible and independent operation. The FACTS technology is a promising technology to achieve complete deregulation of Power System i.e. Generation, Transmission and Distribution as complete individual units. The loading capability of transmission system can also be enhanced nearer to the thermal limits without affecting the stability.
Complete close-loop smooth control of reactive power can be achieved using shunt connected FACTS devices. Static VAR Compensator (SVC) is one of the shunt connected FACTS device, which can be utilized for the purpose of reactive power compensation.. This paper attempts to design and simulate the Fuzzy logic control of firing angle for SVC (TCR & FC-TCR) in order to achieve better, smooth and adaptive control of reactive power. The design, modeling and simulations are carried out for λ /8 Transmission line and the compensation is placed at the receiving end (load end). The results of both SVC (TCR & FC-TCR) devices
Fig.1. Single Phase equivalent circuit and fuzzy logic control structure of SVC
EXPECTED SIMULATION RESULTS:
Fig.2. Uncompensated voltages for R=500 Ω
Fig.3. Compensated voltages for R=500 Ω with TCR
Fig.4. Compensated voltages for R=500 Ω with FC-TCR
Fig.5. Active and Reactive powers of the Tr.line R=200 Ω after compensation with FC-TCR
Fig.6. Active and Reactive powers of the Tr.line for R=200 Ω after compensation with TCR
This paper presents an “online Fuzzy control scheme for SVC” and it can be concluded that the use of fuzzy controlled SVC (TCR & FC-TCR) compensating devices with the firing angle control is continuous, effective and it is a simplest way of controlling the reactive power of transmission line. It is observed that SVC devices were able to compensate over voltages. Compensating voltages are shown in Fig.15 and Fig.16.
The use of fuzzy logic has facilitated the closed loop control of system, by designing a set of rules, which decides the firing angle given to SVC to attain the required voltage. The active and reactive power compensation with SVC devices was shown in Fig.17 and Fig.18. With MATLAB simulations   and actual testing it is observed that SVC (TCR & FC-TCR) provides an effective reactive power control irrespective of load variations.
 Narain. G. Hingorani, “Understanding FACTS, Concepts and Technology Of flexible AC Transmission Systems”, by IEEE Press
 Bart Kosko, “Neural Networks and Fuzzy Systems A Dynamical Systems Approach to Machine Intelligence”, Prentice-Hall of India New Delhi, June 1994.
 Timothy J Ross, “Fuzzy Logic with Engineering Applications”, McGraw-Hill, Inc, New York, 1997.
 Laboratory Manual for Transmission line and fuzzy Trainer Kit Of Electrical Engineering Department NIT Warangal
 SIM Power System User Guide Version 4 MATLAB Manual Periodicals and Conference Proceedings: