Advantages & disadvantages of Harmonics in Power System

Harmonic voltages and currents in a Power System are a result of non-linear electric loads. In a normal AC Power System, the current varies sinusoidally at a specific frequency, usually 50 or 60 Hertz. When a linear electrical load is connected to the system, it draws a sinusoidal current at the same frequency as the voltage, … Read more

How Electrical Circuit Ground in an Aeroplane?

In an Aeroplane, it is only a single wire wiring which carries positive charge to all the systems and electrical units. The Aeroplane body functions as the negative path. This is why all parts of an Aeroplane are always connected with electrical bonding strips. This keeps the complete Aeroplane in a uniform level of charge … Read more

Transformer Differential Protection

What is Differential Protection? Differential Protection is based on the fact that any fault within electrical equipment will result into the difference in current entering it and the current leaving it. Thus by comparing the two currents either in magnitude or in phase or both we can determine a fault and issue a trip decision … Read more

Autoreclosing Philosophy in Distance Protection

What is Auto Reclosure? Autoreclosing is a feature which is provided in the Line Circuit Breaker so that Single Pole of a Breaker may trip and close when command is given to do so. Based on the time duration of fault existing in the Power System, faults can be classified into three categories as Transient … Read more

Concept of Infinite Bus

For understanding the concept of Infinite Bus, we will take some examples. Suppose we take an isolated synchronous generator of capacity 100 kW and supplying a load of, say 50 kW, at 50 Hz and rated voltage, say 400 V. Now if we add a load of 20 kW what will happen? The frequency (speed) … Read more

Reactive Power and Voltage Control of a Transmission Line

For understanding the relationship between the Reactive Power flow in a Transmission Line and Voltage drop, we will consider Short Transmission Line for simplicity. A short transmission line is one whose length is less than 80 km. For short Transmission Line Resistance and Reactance of line is assumed lumped. The important thing for short Transmission … Read more

Power Line Carrier Communication (PLCC)

Power Line Carrier Communication, often called PLCC, is used for speech data transmission as well as protection of Transmission Lines. Carrier current used for Power Line carrier Communication has a frequency range of 80 to 500 kHz. PLCC is mainly for telemetry and telecontrol in modern electrical Power System.     Power Line Carrier Communication … Read more