Principles of 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 […]

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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

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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.

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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

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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

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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

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System Grounding

System Grounding: The process of connecting some electrical part of the power system (e.g. neutral point of a star-connected system, one conductor of the secondary of a transformer etc.) to earth (i.e. soil) is called System Grounding. The system grounding has assumed considerable importance in the fast expanding power system. By adopting proper schemes of

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Grounding or Earthing

Grounding or Earthing: The process of connecting the metallic frame (i.e. non-current carrying part) of electrical equipment or some electrical part of the system (e.g. neutral point in a star-connected system, one conductor of the secondary of a transformer etc.) to earth (i.e. soil) is called Grounding or Earthing. It is strange but true that

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Key Diagram of Substation

Key Diagram of Substation 66/11KV: Fig. 25.10 shows the key diagram of a typical 66/11 kV sub-station. The Key Diagram of Substation can be explained as under: 1. There are two 66 kV incoming lines marked ‘incoming 1’ and ‘incoming 2’ connected to the bus-bars. Such an arrangement of two incoming lines is called a

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Busbar Arrangements in Substations

Busbar Arrangements in Substations: Busbar are the important components in a sub-station. There are several Busbar Arrangements in Substations that can be used in a sub-station. The choice of a particular arrangement depends upon various factors such as system voltage, position of sub-station, degree of reliability, cost etc. The following are the important bus-bar arrangements

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