Tricky but Easy Electrical Engineering!
Being an Electrical Engineer, it is very important to have clear concept of Symmetrical Components used for the analysis of fault or unbalance in a Power System. Basically Symmetrical Components are mathematical modeling used to simplify the calculation while maintain the physical significance of components. The concept of Symmetrical Components can be stated as: … Read more
Magnetic Oil Level gauge or MOG is provided in a Power Transformer to indicate the level of insulating oil in the Conservator. A decrease in level of Transformer Oil in Conservator is an indication of leak and therefore MOG level is an important parameter to be monitored. Normally all Transformers are provided with an expansion … Read more
Sensitive Earth fault Protection scheme is used for the detection of earth fault. Protection against phase to ground faults can be a difficult problem since ground fault currents vary within a large range, becoming almost negligible in some situations. The ground fault current magnitude depends on the power system grounding which can vary from solidly … Read more
Restricted Earth Fault (REF) protection is basically a Differential Protection. The only difference in between the Differential Protection and REF Protection is that, latter protection is more sensitive as compared to the former protection scheme. In earlier posts we have already discussed Differential Protection of Transformer and various characteristics of Differential Protection. In this post … Read more
We have already discussed on the Potential Distribution across the various discs in a Suspension type Insulator. When Suspension type insulator is connected to hold a power conductor carrying electrical power at high voltage, a charging current will flow though the series connected Self Capacitors. As the charging current through each of the Capacitor (Porcelain … Read more
A Suspension Insulator is basically a string of number of porcelain disc connected in series though metallic link. It shall be noted that the number of discs in Suspension Insulator can be increased or decreased by adding extra discs or removing a disc. Figure-a below shows a typical Suspension Insulator. As discussed in above paragraph, porcelain … Read more
The overhead Transmission Line experiences vibrations in vertical plane. This vibration of Transmission Line in vertical plane can be categorized into two groups. 1) Aeoline Vibration 2) Galloping or Dancing of Conductors Aeoline Vibration is of high frequency and low amplitude. The frequency of vibration is of the order of 5 to 40 cycle/second while … Read more
Sag in overhead Transmission line conductor refers to the difference in level between the point of support and the lowest point on the conductor. As shown in the figure above, a Transmission line is supported at two points A and B of two different Transmission Towers. It is assumed that points A and B are … Read more
SOTF Protection stands for Switch On to Fault. This protection is provided for high speed clearance of detected fault immediately after Manual Closure of Circuit Breaker. Let us suppose that a fault is existing and we gave a closing command to Breaker, then in that case SOTF protection will immediately trip the Breaker. SOTF Protection … Read more
The majority of faults on a power system occur between one phase and ground or two phases and ground. These are known as shunt faults and arise from lightning discharges and other over voltages which initiate flashovers. Alternatively, they may arise from other causes such as birds on overhead lines or mechanical damage to cables … Read more