Fractal image compression:Recent technique based on the representation of an image

Storing an image on a computer requires a very large memory. This problem can be averted by the use of various image compression techniques. Most images contain some amount of redundancy that can be removed when the image is stored and then replaced when it is reconstructed.

Fractal image compression is a recent technique based on the representation of an image. The self-transformability property of an image is assumed and exploited in fractal coding. It provides high compression ratios and fast decoding. Apart from this it is also simple and is an easily executable technique.

Fault localization on ungrounded and high resistance grounded low voltage systems

One of the most common and difficult problems to solve in industrial power systems is the location and elimination of ground fault. Ground faults that occur in ungrounded and high resistance grounded systems do not draw enough current to trigger circuit breaker or fuse operation, making them difficult to localize. Techniques currently used to track down faults are time consuming and cumbersome. A new approach developed for ground fault localization on ungrounded and high resistance grounded low voltage systems is described. The system consists of a novel ground fault relay that operates in conjunction with low cost indicators permanently mounted in the circuit. The remote fault relay employs digital signal processing to detect the fault, identify the faulted phase and measure the electrical distance of the fault from the substation. The remote fault indicators are used to visually indicate where the fault is located. The resulting system provides a fast, easy, economical and safe detection system for ground fault localization.

FACTS :A concept introduced by Electric Power Research Institute (EPRI)

FACTS is a concept introduced by Electric Power Research Institute (EPRI), USA.It is actually a group of advanced transmission technologies that rely on high speed, solid-state electronics, rather than electromechanical devices. By this concept, the apparent impedance of a transmission line is controlled according to certain algorithm. Thus the power system operation is made more reliable, controllable and efficient.

FACT system is a promising method, which can be implemented into the system for enhancing system stability by damping out system oscillations. At the heart of FACT are thyristors, which permit control and switching of megawatt levels of power within milliseconds.