ENGINEERING ARTICLES

Service main is the path between the utility company and consumer. Service mains used are the cables, almost PVC cables are used. Power loss through the PVC cables is an important factor, through which it is analysed and estimated that how much percentage of the power is utilised by the customer, how much power is wasted through the cables? In this chapter power loss through secondary distribution system, PVC cables, and behaviour of the utility companies towards the consumers is thoroughly described. Secondary distribution is taken into account so as to clarify the nature of the network and power rating of the circuit. Transformers (Step Down), conductors, structures, insulators and other fittings and fixtures are the component of the secondary system. A Service main is the wire or path between the secondary distribution system and consumer. Service mains almost used in the distribution system are PVC cable. Manufacturing, conductor size, current rating and power loss through these ca...

In renewable energy sources Power quality of distribution system can also be affected by non-linear loads.Non-linear loads are a source of harmonic currents.Renewable energy sources do not directly supplies AC power to the consumers.Renewable sources generate DC power which is then converted to AC with the help of electronic based inverters. Those electronic circuits associated with control and interconnection of renewable energy sources will inject harmonics in the system to which these are connected.

Solar photovoltaic (PV) cells and wind mill dependent on climatic change to work and generate electrical energy. Therefore, when these energy sources working alone they are not good power supply. Emerging of solar and wind sources are more valued in electrical energy generation. Such a type of system is called Hybrid system.Thus a hybrid power system of renewable source with grid supply improves the stability of system. With hybrid system there are period of time when neither of sources produce energy. In separate systems energy storage is necessary to overcome this situation and provide energy during such periods. Power electronic devices such as inverter and others are play very important role in the hybrid power system. The energy which extracted is used to charge batteries. The inverter is interconnected with consumer loads and to the electrical power grid. Hybrid system is the operation of two or more than two sources which utilize to the single load. Merits of hybrid power ...

Equipments are designed for operation at a fixed frequency called fundamental frequency.Harmonics are waveforms of the frequencies which are integral multiples of fundamental frequency. As per the calculations of the harmonics they are defined in the odd and even harmonics. However odd harmonics are important to know. Odd harmonics are defined as below: If Fundamental Frequency is 50Hz, then 3rd Harmonic = 3 x 50Hz =150Hz, 5th Harmonic = 5 x 50Hz =250Hz and 7th harmonics= 7 x 50Hz = 350Hz. Harmonics are cause by non-linear loads and in which current is not comparative to the applied voltage. Electronic devices are major source of harmonics. With a non-linear load, no one can easily forecast the link among voltage and current but for it you have an exact for each device.

Renewable energy sources are available free of cost, smooth during operationandclean source of energy. Renewable energy sourceshavelow operating and maintenance costand can be easily built.Solar and wind energy are almost widely used as the main renewable energy resource.Wind mills can be installed in bulk and later connected to national grid on commercial basis. On the other hand wind mills can also be installed by individual consumers to meet their loads. Solar cells can be used in homes and offices to generate electricity. Future aspects of solar and wind sources are bright and can play an important role in the world.

It can be distinct as “Power problems existing in voltage, current or frequency variation that result in failure of consumer’sequipment”. There are a lot of ways inside power supply can be of poor power quality. It is vital to know the different types of power quality variations that can cause troubles with receptive loads. Some important power quality problems are following. v Disturbance in supply v Voltage dip v Voltage swells v Poor power factor v Harmonics These affect the performance of the power system components and results in huge capital loss. The most important problem of the power quality in waveform distortion is harmonics.

In this section of the report, nine essential elements that constitute an effective cable condition monitoring (CM) program are presented. These elements are as follows: 1. Selection of cables to be monitored 2. Development of database for monitored cables 3. Characterize and monitor service environments 4. Identify stressors and expected aging mechanisms 5. Select CM techniques suitable to monitored cables 6. Establish baseline condition of monitored cables 7. Perform test & inspection activities for periodic CM of cables 8. Periodic review & incorporation of plant & industry experience 9. Periodic review & assessment of monitored cables condition Each element will be described in detail in the following subsections. The purpose for each of the individual elements of the cable CM program will be presented along with how the element fits into the overall cable CM program. Guidance will be provided for implementation...