Research Background Comparative Study Of Leakage Current On Insulation Surface Condition.

CHAPTER 1 INTRODUCTION

1.1 Research Background

Electrical insulation is a significant component in all electrical systems. It is really important in the main procedure to maintain the functioning and the refuge of the electrical appliances and creature. Nowadays, the use of polymer as an insulator is widely used all over the world, despite using the glass or ceramic as an insulator in the electrical system. This is due to the polymer insulator have better ease of handling and installation, not causing pollution and resistance to vandalism rather than the glass or ceramic insulator. Nowadays, the demands for polymer insulator are much higher and have become a replacement for all traditional insulators such as porcelain, glass, and ceramics. Due to its advantage in the ratio of strength-to-weight is better than the other insulator, it has attracted lots of users to use polymer insulator as to reduce cost on insulator installations. The utilization of glass ceramic insulators on the electrical energy transmission system which tend to accept higher voltage are no longer profitable because the glassceramics density is great, long, fragile and losses. It has a higher cost of construction and maintenance of electric power network [1]. The degree of effectiveness of insulator actually depends on how much leakage current that flow through the insulator itself. Leakage current is any current that can flow either through the body or over the insulator when the idle current is zero. In electrical systems and the use of home appliances, the leakage current is often associated with the users safety and the public. To better understand the situation, taking the example of an electric motor that has a weak winding insulation. Insulation may wear at some point and mostly due to long time running, heating or some other factor. The voltages at that stage will be shifted to the core of the motor . The core is linked to motor body so, a voltage will appear along the outer surface of the motor body. If the body is grounded, this potential difference will make a net current flow to ground. This current is passed directly from point of insulation failure. The magnitude of this current depends only on the resistance of ground [2].

1.2 Motivation