Electrical circuits - lecture

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The effects of three-phase harmonics

The effects of three-phase harmonics on circuits are similar to the effects of stress and high blood pressure on the human body. High levels of stress or harmonic distortion can lead to problems for the utility's distribution system, plant distribution system and any other equipment serviced by that distribution system. Effects can range from spurious operation of equipment to a shutdown...

HIGH-VOLTAGE (HV) TRANSMISSION LINE PROTECTION SCHEMES

Most transmission lines are protected by directional distance relays. These may serve as backup protection to other schemes in service, or these may be the sensing components in various forms of differential protection. Figure below shows the basic elements of a PLC (power line carrier)...

String Effeciency and methods to improve String Effeciency

The ratio of voltage across the whole string to the product of number of discs and the voltage across the disc nearest to the conductor is known as string efficiency i.e.,   String efficiency is an important consideration since it decides the potential distribution along the...

Voltage ranges

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Synchronization process

There are five conditions that must be met before the synchronization process takes place. The source (generator or sub-network) must have equal line voltage, frequency, phase sequence, phase angle, and waveform to that of the system to which it is being synchronized.   Waveform and phase sequence are fixed by the construction of the generator and its connections to the system....

Sizing of protective earthing conductor

Below is based on IEC 60364-5-54. This table provides two methods of determining the appropriate c.s.a. for both PE or PEN conductors.     c.s.a. of phase conductors Sph (mm2) Minimum c.s.a. of PE conductor (mm2) Minimum c.s.a. of ...