What is transmission and subtransmission?

What is transmission and subtransmission?

Subtransmission is part of an electric power transmission system that runs at relatively lower voltages. It is uneconomical to connect all distribution substations to the high main transmission voltage, because the equipment is larger and more expensive.

What is subtransmission system?

Subtransmission systems are those circuits that supply distribution substations. Distribution circuits are occasionally supplied by high-voltage transmission lines such as 230 kV; such high voltages make for expensive high-side equipment in a substation.

What is considered distribution voltage?

Primary distribution voltages range from 4 kV to 35 kV phase-to-phase (2.4 kV to 20 kV phase-to-neutral) Only large consumers are fed directly from distribution voltages; most utility customers are connected to a transformer, which reduces the distribution voltage to the low voltage “utilization voltage”, “supply …

Is 12 kV high voltage?

High voltage is defined as any voltage over 1000 volts. Those of 2 to 33 kV are usually called medium voltage cables, those over 50 kV high voltage cables.

Why is AC used for transmission?

Hence, the voltage through transmission lines is very high, which reduces the current, which in turn minimizes the energy lost through transmission. This is why alternating current is preferred over direct current for transmitting electricity, as it is much cheaper to change the voltage of an alternating current.

What is the difference between transmission and distribution system?

The core difference between transmission and distribution power lines is that transmission power lines are for long-distance, high-voltage electricity transportation, whereas distribution power lines are for shorter distances and lower voltage electricity transportation.

What is the use of distribution transformer?

Distribution transformers are generally used in electrical power distribution and transmission systems. This class of transformer has the highest power, or volt-ampere ratings, and the highest continuous voltage rating. The power rating is normally determined by the type of cooling methods the transformer may use.

What is SELV voltage?

Glossary: SELV SELV (Safety Extra Low Voltage) describes a voltage that is set so low that in the event of direct touch either during proper operation or in the event of a single fault there is no danger of electric shock due to touch current.

Is 66 kV high voltage?

Distribution lines The voltage of electricity conducted by distribution powerlines may vary from 415 volts (V), which are low voltage, to 66 kV (66,000 volts), which are high voltage.

Is 13.8 kV high voltage?

If the distances from the main utility substation of the campus to the individual buildings are great, higher voltages could be used, but the 13.8-kV distribution system is very common. Other common voltages are 12.47 kV, 24 kV, and 24.9 kV (nominally 25 kV).