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Ground Potential Rise (GPR) refers to the increase in electrical potential between the ground and a point of reference when a fault occurs on a power system. It is caused by lightning or high voltage ground faults. Under these conditions the potential of the soil surrounding the point of ground fault increases to dangerous levels. … Read more
Grounding systems are required not only to ensure the safety of the personnel and the safe operation of equipment but also to protect the system from lightning and ensure accurate measurement of electrical parameters. Here are a few factors that influence the requirements for a good grounding system. The following are the major factors influencing … Read more
It is vital to maintain good ground in a system. In order to ensure that, ground resistance measurements and tests are conducted on existing earth electrodes at periodic intervals after their installation. This ensures the resistance in the ground is at an acceptable level and is maintained. Here are the different methods of ground/ earth … Read more
The fall of potential method or 3-point method is the most commonly used method to measure ground resistance. It is used to determine the earth resistance of an existing grounding system. The fall of potential method requires only a minimum amount of calculation and is best suited for small installations. It can be used for … Read more
One of the key elements affecting ground resistance is soil resistivity. Soil resistivity measurements are conducted before setting up an earthing system, in order to ensure an effective earthing. Good soil models are the basis of all grounding designs and they are developed from accurate soil resistivity testing. The ground/earth resistance measurements are conducted to … Read more
Grounding transformers are used to obtain a neutral when an existing delta-connected or ungrounded systems are to be grounded. These transformers provide a path for the flow of fault currents during unbalanced ground faults. They can be found in transformer substations where neutral might not be available as the transformer windings are delta connected. Types … Read more
A resonant grounded system can significantly reduce the ground fault currents. This grounding system basically consists of a tuned reactor connected between the neutral and the ground that resonates with the line-to-ground capacitance of the system so that the magnitude of the ground current is reduced. This reactor is knowns as a ground-fault neutralizer or … Read more
In a reactance grounded system, the neutral is connected to the ground through an inductance (inductive reactance). The magnitude of the ground fault current can be limited to a value close to the three-phase short circuit current of the system (since it is a function of the phase to neutral voltage and the neutral impedance). … Read more
Effective electrical earthing plays an important role in safeguarding people from the risk of electric shock and ensures a low impedance path for electric discharges to pass to the general mass of the earth under both normal and fault conditions. In this article, let’s discuss the various earthing systems as per IEC 60364 and BS … Read more
Ground and/or Earth are generally used to define a common reference point for power/signal. While IEC (IEV ref 195-01-01) defines this reference point as earth, IEEE (Standard Std 142-2007) defines the same point as ground and NEC defines ground itself as a connection to the earth. But are earthing and grounding the same, let’s find … Read more
