TN-S system

TN-S system Separate neutral and protective conductors throughout the system ... 

Figure 3.32 Earth fauft loop path for a TN-S system.

Figure 3.34 Cable sheath earth supplies (TN-S system) showing earthing and bonding arrangements...

Regulation 542-01-02 refers to TN-S systems where the supply company runs a protective conductor from the distribution transformer earth into the consumer s premises and makes it available for connection to the consumer s main earth terminal. This protective conductor may consist of the metallic sheath/armour of the underground service cable or an earthing conductor connected to the protective conductor of an overhead line. 

For TT systems, the minimum sizes of buried earthing conductors are given in Table 54A where a buried electrode is used. For other electrodes, such as a building metal frame and for TN-S systems, the size may be selected from Table 54G or calculated from the formula in section 543-01-03. For TT systems, however, it may not be possible to calculate because the earth fault loop impedance is not likely to be known until it can be measured. 

Rgure 5.14 Cable Sheath Earth Supplies (TN-S System) Showing earthing and main protective equipotential bonding arrangements. 

No ni ial syste n voltage kV r.m.s.) Rated maximum system voltage V, kV(r.tn.s.) Standard one-minute power frequency withstand voltage KV (r.m.s.) Standard lightning impulse (1.2/50 ps) withstand voltage phase to ground kV (peak) ... 

The components making the autonomous system were integrated electrically at 400 V (TN-S) 50 Hz. A separate 315-kVA, 22/0.4-kV transformer connected a 1.5 km cable, transmitting power from the autonomous system to the customer substation. All the 10 households were connected to the customer substation at 230V, which is the standard voltage level in Norway. The customer substation also... 

Reversibility is reached asymptotically, but for > 10 tn/s the system can be considered to be reversible. To generalize this curve, we have shown the values of the rate constant also in dimensionless form as... 

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