Types of Faults in Power Distribution System | Causes of Electrical Fault

Electrical Faults in Power Distribution System:

What is electrical faults: Normally, In an electric power system operates under balanced conditions. Faults or fault current of a distribution system as like any abnormal electric current. This abnormal electric current or short circuit current is called fault.

Types of faults in power system: Here we will described only about of two types faults i,e.
1. Symmetrical Faults 2. Unsymmetrical Faults
  1. Symmetrical fault-: It is the type of fault in which generally occurs in a three phase system which can be transmission or distribution. In such types of faults in which generally occurs in a three phase system, which can be transmission or distribution. Condition are mentioned below.
  • We can say the lines displaced by an equal angle (i.e. 120° in three phase line). It is the most severe type of fault involving largest current, but it occurs rarely.
  • Three-Phase-to-Ground fault (LLLG) : In other case if the three phase are connected or sorted to the ground then this type of all is symmetrical fault. In transmission line faults, roughly 5% are symmetric.

  2. Unsymmetrical fault:  It is the type of fault in which two phase can be sorted to the ground or any  one phase Can be sorted to the ground. In this condition the remaining system phase remain fully operation.

  • Line-to-Line fault (LL) : Such types of fault occur, at short circuit between lines, caused by ionization of air, or when lines come into physical contact or touches with each other at any conditions. For example due to a broken insulator. Roughly 5% – 10% are un-symmetric line-to-line faults.
  • Line-to-Ground fault (LG) : This types of fault occur, when lines come into physical contact, for example due to a broken insulator.
  •  Double Line-to-Ground fault (LLG) : There are many condition in which any two phase short-circuited to each other and often to earth.

Effect of Electrical fault:-

  • Heavy short circuit current can damage the equipment.
  •  high mechanical stress on the conductor and the insulators.
  •  excess heating of the conductors.
  •  heavy arcing  due to Excess current.
  •  there can be e unbalance in the supply voltage.
  •  reduction in the supply voltage.
  •  loss of system stability
  •   reliable operation in various  machineries is hampered. 

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