Core voltage

Fig. 7.71 Effect of different TAC Offset in a reversed start-stop system. Left Increased offset shifts the curve right, i.e. shifts the recorded time interval to an earlier part of the signal. Right For very small and very large offsets the beginning and the end of the TAC characteristic come into view. A Offset 0, B Offset 50% of maximum TAC core voltage...

Calculated transient core voltages on a tunnel-installed cable (a) cross-bonded, (b) mixed. Calculated transient core voltages on a tunnel-installed cable (c) homogeneous, and (d) solidly bonded. 

The maximum sheath voltage at the first cross-bonded joint shown in Figure 3.15a becomes 0.05 pu, which is about 40% of the core voltage at the time. This voltage is generated by a reflection at the cross-bonded joint. This is an inherent characteristic of the cross-bonded... 

Figure 3.14d shows the transient response of the core voltage in a solidly bonded cable. It shows a stair-like waveform with a length of 70 ps. This length is determined by the round-trip time shown in Equation 3.89. Sheath voltages of the solidly bonded cable are much smaller than those of the cross-bonded cable. The results indicate that not all cross-bonded cables can be simplified by a solidly bonded cable from the viewpoint of not only the sheath voltages but also the core voltages. 

Core voltages to the sheath and counterpoise, (a) Sending end grounding, (1) No lead wire inductance (Case Cl-02) and (2) lead wire inductance considered (Case Cl-12). (b) Receiving end grounding, (1) No lead wire inductance (Case C1-03) and (2) Lead wire inductance considered (Case Cl-13). (c) Grounding at both ends, (1) No lead wire inductance (Case Cl-04) and (2) Lead wire inductance considered (Case Cl-14). 

Calculated transient core voltages on a tunnel-installed cable (a) cross-bonded, (b) mixed. 

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