Category: POWER SYSTEM

Voltage Transformer Earthing

Voltage Transformer Earthing: In this method of neutral earthing, the primary of a single-phase Voltage Transformer Earthing is connected between the neutral and the earth as shown in Fig. 26.17. A low resistor in series with a relay is connected across the secondary of the voltage transformer. The Voltage Transformer Earthing provides a high reactance […]

Resonant Grounding

Resonant Grounding or Arc Suppression Coil Grounding: We have seen that capacitive currents are responsible for producing arcing grounds. These capaci­tive currents flow because capacitance exists between each line and earth. If inductance L of appro­priate value is connected in parallel with the capacitance of the system, the fault current IF flowing through L will be […]

Resistance Grounding

Resistance Grounding: In order to limit the magnitude of earth fault current, it is a common practice to connect the neutral point of a 3-phase system to earth through a resistor. This is called Resistance Grounding. When the neutral point of a 3-phase system (e.g. 3-phase generator, 3-phase transformer etc.) is connected to earth (i.e. […]

Solid Grounding

Solid Grounding or Effective Grounding: When the neutral point of a 3-phase system (e.g. 3-phase generator, 3-phase transformer etc.) is directly connected to earth (i.e. soil) through a wire of negligible resistance and reactance, it is called Solid Grounding or Effective Grounding. Fig. 26.11 shows the solid grounding of the neutral point. Since the neutral […]

Neutral Grounding

Neutral Grounding: The process of connecting neutral point of 3-phase system to earth (i.e. soil) either directly or through some circuit element (e.g. resistance, reactance etc.) is called Neutral Grounding. Neutral grounding provides protection to personal and equipment. It is because during earth fault, the current path is completed through the earthed neutral and the […]

Ungrounded Neutral System

Ungrounded Neutral System: In an ungrounded neutral system, the neutral is not connected to the ground i.e. the neutral is isolated from the ground. Therefore, this system is also called isolated neutral system or free neutral system. Fig. 26.7 shows ungrounded neutral system. The line conductors have capacitances between one another and to ground. The […]