Er_SAPatel

 Comparison Between Overhead and Underground System

  High-resistance grounding system :   High-resistance grounding (HRG) systems are commonly used in plants and mills where continued operation of processes is paramount in the event of a fault. High-resistance grounding is normally accomplished by connecting the high side of a single-phase distribution transformer between the system neutral and ground, and connecting a resistor across the low-voltage secondary to provide the desired lower value of high side ground current. With an HRG system, service is maintained even during a ground fault condition. If a fault does occur, alarm indications and lights help the user quickly locate and correct the problem or allow for an orderly shutdown of the process. An HRG system limits ground fault current to between 1A and 10A. Advantages Limits the ground fault current to a low level. Reduces electric shock hazards. Controls transient overvoltages. Reduces the mechanical stresses in circuits and equipment. Maintains continuity of service...

  Solidly grounded system  :   This type of grounding system is most commonly used in industrial and commercial power systems, where grounding conductors are connected to earth ground with no intentional added impedance in the circuit. A main secondary circuit breaker is a vital component required in this system, although it has no bearing in other grounding systems. This component is large in size because it has to carry the full load current of the transformer. Back-up generators are frequently used in this type of grounding system in case a fault shuts down a production process. When this happens, the generators become solidly grounded. However, it’s important to note that the generators aren’t designed for the larger short circuit current associated with solidly grounded systems. A solidly grounded system has high values of current ranging between 10kA and 20kA. This current flows through grounding wires, building steel, conduit, and water pipes, which can cause major...

  Advantages of earthing The main  advantages of electrical earthing  are the following: Ensures the safety of electrical appliances and devices from the excessive amount of electric current. Helps in the flow of electric current directly inside the ground. Keeps the electric appliance safe from the damage It protects building breakdown from the lightning It shields from fire occurred due to an electric short circuit and saves goods from fire. Earthing helps in the protection of overvoltage, stabilization of voltage. Earthing prevents injury damage and death caused by electric current. It helps in avoiding the risk of fire in electrical installation systems. It ensures the safety of electrical appliances and devices from the excessive amount of electric current. The earthing provides the way to default current even after the failure of the insulation. The earthing protects the appliances from high voltage surges and lightning discharge. Earthing keeps the voltage constant...

  Plate Earthing Diagram – Explained Earthing is the connection of all the neutral points present in the supply of the system to create immediate discharge of the electrical energy during a fault without any danger. Earthing provides an alternate path for the fault current to flow and ensures that all the exposed conducting materials do not reach their respective maximum potentials. A good earthing system always has low impedance to make sure that sufficient current can flow through the safety device and disconnects from the supply during the occurrence of fault current. A good earthing system protects the personnel against electric hazards and safeguards electrical devices, appliances, power tools, machinery, etc. from current leakage. Properly designed earthing also avoids interference with the communication circuits present in the system. There are many types of earthing systems which include plate earthing, pipe earthing, rod earthing, chemical earthing.   PLATE EARTHING: ...

  A   multimeter   is a   measuring instrument   that can measure multiple electrical properties.  A typical multimeter can measure   voltage ,   resistance , and   current , in which case it is also known as a   volt-ohm-milliammeter   ( VOM ), as the unit is equipped with   voltmeter ,   ammeter , and   ohmmeter   functionality.  Some feature the measurement of   additional properties   such as temperature and volume. Analog multimeters use a microammeter with a moving pointer to display readings.  Digital multimeters  ( DMM ,  DVOM ) have numeric displays and have made analog multimeters obsolete as they are cheaper, more precise, and more physically robust than analog multimeters.