Transient performance of grounding grids

Comparison between utility sub-station and imitative earthing systems when subjected under lightning response

“…However, not all studies on the performance of earthing systems observed this reduction of earth resistances, and different peak times for voltage and current traces when subjected under high impulse currents. Some studies [9,13] found that the earth resistance values are almost equal to that measured at low magnitude currents and at power frequency, and independent of current magnitudes. The voltage and current peaks are also found to occur at the same time.…”

“…A number of publications [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] investigated the earthing system performance by experimental or computational methods. However, some authors [5][6][7][8] allow for non-linear behaviour and the others [1][2][3][4][9][10][11][12][13][14][15][16] did not incorporate the effect of non-linear behaviour into their investigations.…”

Transient Grounding Impedance of Electrode Elements for Grounding Mat

“…We changed the method of the measurement for impulse response as shown in Fig.9 because the reflection from the end of the electrode has to be measured before the arrival of the reflection from the signal wire, but the limit of the laboratory room cannot enlarge the vertical wire shown in Fig.2. We removed the vertical wire and apply the voltage source directly to an electrode model as conventional method [6][7]. There is an electrode located at lcm under the water surface and 9cm over the ground plate.…”

“…We should consider the discharge in ground, but it is quite difficult to grasp the reliable result under the high voltage surge in grounding electrode systems [4][5][6]. Therefor, a low voltage pulse was used for experiments because the discharge of the soil decreases the surge impedance but never increases.…”

Generalized pi-circuit tower grounding model for direct lightning response simulation

“…They are accurate but difficult to implement, and also computationally expensive when applied to the grounding systems used at HV and EHV level; moreover, it is difficult to simulate soil ionization. Lastly, circuit-based models [11][12][13][14] consist of lumped parameter circuits which include all mutual couplings between the grounding conductors. Although less accurate than field-based ones, circuit models are less computationally expensive and easier to implement, especially with regard to soil ionization.…”