Tower footing impedance

In Japan, modeling a tower footing impedance as a simple linear resistance Rf is recommended, although a current-dependent nonlinear resistance is recommended by the IEEE and the CIGRE [16,18,20]. The inductive and capacitive characteristics of the foot-ing impedance, as shown in Figure 2.40, are well known [10]. The recom-mended value of... [Pg.224]

The tower-footing impedance is always represented as a resistance as in Table 2.4 recommended by guides on insulation design and coordination of transmission lines and substations [26]. However, it is not pure resistance, but shows an inductive or a capacitive nature (see Figure 2.40) as investigated by many authors [10,15,23,31]. [Pg.231]

Model circuit of tower-footing impedance, (a) RC circuit and (b) RL circuit. [Pg.481]

Figure 2.46 shows the effect of tower footing impedance on the tower top voltage in comparison with a measured result on a 500 kV transmission tower [23,31]. The inductive footing impedance shows a reasonable agreement with the measured result, but the resistive/capacitive impedance shows a far more oscillatory waveshapes. In fact, many measured results of the grounding electrode impedance show the inductive characteristic [32]. It should be noted that the effect of the tower surge impedance, that is, the effect of the... [Pg.190]

It is well known that tower surge impedance and footing impedance affect lightning surges significandy. Tower surge impedance is a function of the height and radius of the tower as... [Pg.230]

Influence of a tower model on a tower top voltage, (a) Measured results, (b) Frequency-dependent tower model with a resistive-footing impedance, (c) Distributed line tower model with various footing impedances. [Pg.232]

Vf, Rfare the tower foot voltage and footing impedance... [Pg.253]

Rogers, E. J. 1981. Impedance characteristics of large tower footings to a 100 ps wide square wave of current. IEEE Trans. Power App. Syst. 100 66-71. [Pg.560]

Vf, Rf are the tower foot voltage and footing impedance Ig, Zg are the GW current and surge impedance 4, Z are the PW current, voltage, and surge impedance Z is the mutual impedance between GW and PW... [Pg.209]

System Voltage (kV) Lightning Current (kA) Tower Height/Geometry (m) Surge Impedance (i3) Footing Resistance... [Pg.223]

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