Want this question answered?
Alternator output voltages are typically restricted to around 25 kV to limit their physical size and the centrifugal forces to which they are subjected. In the UK, this voltage is then typically raised to 400 kV for transmission.The voltages to which you are referring to are typical of the voltages used in the UK's high-voltage distribution system. 'Grid' substations typically transform transmission voltages of 132 kV down to 33 kV (or, less commonly, 66 kV), and 'primary' substations then transform distribution voltages of 33 kV down to 11 kV.
Multiples of 11 kV are used in many countries. The idea is to deliver a round number of volts so you add on 10% to allow for line losses. So 10 kV becomes 11 kV. In practice lines are operated without a 10% voltage drop now because it represents an unacceptable waste of energy, but we have stuck with 11 kV etc. Common supply voltages used for area distribution are 6.6 kV, 11 kV, 33 kV, 66 kV and 132 kV.
Every conductor (in this case, the transmission line) has a finite resistance. so for example let us say it has a resistance of 1 ohm over a distance of 1 km. then, if the current through the conductor is say 100 Amperes, you will have a voltage drop of 100 volts across a length of 1 km. So, a line carrying 100 Amps at 25 kV will have an effective voltage of 24.9 kV
All sinusoidal AC voltages are multiples of 1.1. This is due to the form factor, which is the ratio of the quadratic mean value of the voltage with the average voltage, which is pi/2√2=1.1 (approximately). It also provides the most economic means of constructing step up/down transformers.AnswerIn the UK, 33 kV (along with 66 kV) is considered to be a primary distribution voltage level, whereas 11 kV is secondary distribution voltage level. Incidentally, the correct symbol for 'kilovolt' is 'kV', not 'kv'.
33 KV plus or minus 3 percent
It isn't. In the UK, transmission and distribution voltages are 400 kV, 275 kV, 132 kV, 66 kV, 33kV, and 11 kV.
Please refer Chapter 1, Page 2 of "Insulation coordination for power systems" by Andrew R. Hileman that gives a good description of the term BIL and BSL (Basic Switching Impulse Withstand Voltage).
It used to be a convention to add 10% to allow for transmission losses, so the voltages were always described as 11 kV, 33 kV, 66 kV and 132 kV. Later standards in the UK grid are 275 kV, which is a multiple of 11, and 400 kV which is not.
34.5, 69, 115, 161, 230, 345, 500kV are all common transmission (and distribution) voltages. They aren't all multiples of 11.Additional CommentI think that the questioner is British because, in the UK, most transmission and distribution voltages are multiples of 11. These are 11 kV, 33 kV, (66 kV*), and 275 kV. The exception is the highest transmission voltage of 400 kV.(*66 kV is less common these days)
Alternator output voltages are typically restricted to around 25 kV to limit their physical size and the centrifugal forces to which they are subjected. In the UK, this voltage is then typically raised to 400 kV for transmission.The voltages to which you are referring to are typical of the voltages used in the UK's high-voltage distribution system. 'Grid' substations typically transform transmission voltages of 132 kV down to 33 kV (or, less commonly, 66 kV), and 'primary' substations then transform distribution voltages of 33 kV down to 11 kV.
In the UK a line of pylons carrying the supergrid at 400 kilovolts can carry up to about 2000 Megawatts. Pylons also carry circuits working at lower voltages, 275 and 132 kV, 66 kV in some places, and on small pylons 33 kV.
i working 66 kv and 220 kv substation. over substatin transformer and 66 kv sf6 bracker use i intersted for working of idmt realys with breacker tripping coil.
i working 66 kv and 220 kv substation. over substatin transformer and 66 kv sf6 bracker use i intersted for working of idmt realys with breacker tripping coil.
Phase to phase clearance should be around 11.5 inches.
Multiples of 11 kV are used in many countries. The idea is to deliver a round number of volts so you add on 10% to allow for line losses. So 10 kV becomes 11 kV. In practice lines are operated without a 10% voltage drop now because it represents an unacceptable waste of energy, but we have stuck with 11 kV etc. Common supply voltages used for area distribution are 6.6 kV, 11 kV, 33 kV, 66 kV and 132 kV.
33 kv.
In the UK, 11-kV power lines are part of the distributionsystem, not the transmission system. The system is split as follows:transmission-system voltages: 400 kV, 275 kV, and 132 kV.primary-distribution system voltages: 66 kV and 33 kV.secondary-distribution system voltages: 11 kV and 400/230 V