Difference between revisions of "Grid Standard Proposal 2"

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(from discussion with Mike Delaney)
 
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==Reasoning==
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==Reasoning==  
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Higher frequencies are desirable because [insert reasoning here].
 
  
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There are limiting factors, however. Electricity, when recified, can cause a hum. 1 kHz would be like having the microwave beeping continuously. Higher frequencies can radiate like a radio transmitter. 400 Hz is a frequency that has in the past been used by trains and busses for running flourescent lights.
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[[Electrical resistance]]<ref>[http://en.wikipedia.org/wiki/Electrical_resistance Electrical Resistance]</ref> of [[Electrical Conductors|conductors]]<ref>[http://en.wikipedia.org/wiki/Electrical_conductor Electrical Conductor]</ref> varies with the [[frequency]]<ref>[http://en.wikipedia.org/wiki/Frequency Frequency]</ref>. The [[Electrical resistance|resistance]] ([[impedance]])<ref>[http://en.wikipedia.org/wiki/Electrical_impedance Electrical Impedance]</ref> seen by [[AC]]<ref>[http://en.wikipedia.org/wiki/Alternating_current Alternating Current]</ref> system can be much lower than the [[DC]]<ref>[http://en.wikipedia.org/wiki/Direct_current Direct Current]</ref> resistance of the same piece of wire.  
  
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Also, the degree of [[inductive coupling]]<ref>[http://en.wikipedia.org/wiki/Inductive_coupling Inductive Coupling]</ref> between [[primary coil]]<ref>[http://en.wikipedia.org/wiki/Primary_coil Primary Coil]</ref> and [[secondary coil]]<ref>[http://en.wikipedia.org/wiki/Secondary_Coil Secondary Coil]</ref> in [[transformer|transformers]]<ref>[http://en.wikipedia.org/wiki/Transformer Transformers]</ref> can increase with higher frequencies. Therefore, higher frequencies are desirable because transformers used for converting [[voltage]]<ref>[http://en.wikipedia.org/wiki/Voltage Voltage]</ref> can be both smaller and more efficient.
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There are limiting factors, however.
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*AC can cause a hum, typically the changing [[magnetic field]] <ref>[http://en.wikipedia.org/wiki/Magnetic_field Magnetic Field]
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</ref>causes the transformer core plates to expand and contract, causing sound waves to be generated. In a habitable area, a hypothetical 1 kHz would be like having the microwave oven beeping continuously. But on Earth, lower frequencies are used in domestic situations, and good design can eliminate any detectable hum.
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*Higher frequencies in the [[RF]] ([[Radio Frequency]])<ref>[http://en.wikipedia.org/wiki/Radio_frequency Radio Frequency]</ref> range can radiate like a radio transmitter, and cause [[EMI]] ([[Electro Magnetic Interference]]<ref>[http://en.wikipedia.org/wiki/Electromagnetic_interference Electro Magnetic Interference]</ref>). EMI in turn requires shielding, special grounding and other techniques know as [[EMC]] ([[Electro Magnetic Compatibility]])<ref>[http://en.wikipedia.org/wiki/Electromagnetic_Compatibility Electromagnetic Compatibility]</ref> Design to reduce the amount of [[RF leakage]] and/or reduce the amount of coupling to the electronic "victim". EMI can be a problem for sensitive electronic equipment, such as some scientific experiments
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*At higher frequencies electricity tends to travel more towards the outside of the wire ([[Skin Effect]]<ref> [http://en.wikipedia.org/wiki/Skin_effect Skin Effect]
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</ref>) reducing efficiency. Some conductors have a thin highly conductive outer layer (e.g. silver) and a lower conductive inner core made of cheaper material, to take advantage of this phenomenon.
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Various frequencies are used in AC systems. 50HZ is used in the UK for domestic 240V AC, and the USA and Canada use 60 Hz at 110 V. 400 Hz is a frequency that has in the past been used on trains, buses and aircraft for running [[fluorescent lights]]<ref>[http://en.wikipedia.org/wiki/Fluorescent_lights Fluorescent Lights]</ref>. Aircraft mostly utilize 400 Hz power systems, the reduction in core and winding weight more than offsets the small increase in thermal losses. Even higher frequencies are used for [[HT]] ([[high tension]])<ref>[http://en.wikipedia.org/wiki/High_voltage High Tension]</ref> long distance [[Electric_power_transmission|power transmission]]<ref>[http://en.wikipedia.org/wiki/Electric_power_transmission Electric Power Transmission]</ref> on Earth.
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Interesting lunar ISRU scenario: large quantities of iron dust are available on the Moon. So lunar transformers can have massive cores, which means low frequencies could be more attractive, because thermal losses become more of a concern, and copper or gold wires imported from Earth need to be as thin and light as possible.
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==External References (Mostly on wikipedia)==
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<div class="references-small" style="-moz-column-count: 2; column-count: 2;">
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<references/>
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[http://en.wikipedia.org/wiki/Electric_field Electric Field]</div>
  
 
==Pros==
 
==Pros==
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[[Category:Life Support (Power Supply)]]
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[[Category:Power Supply]]
 
[[Category:Urban Planning]]
 
[[Category:Urban Planning]]
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[[Category:Electrical Specifications]]
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[[Category:Power Grid Specifications]]
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[[Category:Alternating Current Specifications]]
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[[Category:Standards Proposals]]
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[[Category:Civil Engineering]]

Latest revision as of 11:29, 9 October 2013

Specification

Type Alternating Current
Voltage 250 Volts
Frequency 400 Hz


Reasoning

Electrical resistance[1] of conductors[2] varies with the frequency[3]. The resistance (impedance)[4] seen by AC[5] system can be much lower than the DC[6] resistance of the same piece of wire.

Also, the degree of inductive coupling[7] between primary coil[8] and secondary coil[9] in transformers[10] can increase with higher frequencies. Therefore, higher frequencies are desirable because transformers used for converting voltage[11] can be both smaller and more efficient.

There are limiting factors, however.

  • AC can cause a hum, typically the changing magnetic field [12]causes the transformer core plates to expand and contract, causing sound waves to be generated. In a habitable area, a hypothetical 1 kHz would be like having the microwave oven beeping continuously. But on Earth, lower frequencies are used in domestic situations, and good design can eliminate any detectable hum.
  • Higher frequencies in the RF (Radio Frequency)[13] range can radiate like a radio transmitter, and cause EMI (Electro Magnetic Interference[14]). EMI in turn requires shielding, special grounding and other techniques know as EMC (Electro Magnetic Compatibility)[15] Design to reduce the amount of RF leakage and/or reduce the amount of coupling to the electronic "victim". EMI can be a problem for sensitive electronic equipment, such as some scientific experiments
  • At higher frequencies electricity tends to travel more towards the outside of the wire (Skin Effect[16]) reducing efficiency. Some conductors have a thin highly conductive outer layer (e.g. silver) and a lower conductive inner core made of cheaper material, to take advantage of this phenomenon.

Various frequencies are used in AC systems. 50HZ is used in the UK for domestic 240V AC, and the USA and Canada use 60 Hz at 110 V. 400 Hz is a frequency that has in the past been used on trains, buses and aircraft for running fluorescent lights[17]. Aircraft mostly utilize 400 Hz power systems, the reduction in core and winding weight more than offsets the small increase in thermal losses. Even higher frequencies are used for HT (high tension)[18] long distance power transmission[19] on Earth.

Interesting lunar ISRU scenario: large quantities of iron dust are available on the Moon. So lunar transformers can have massive cores, which means low frequencies could be more attractive, because thermal losses become more of a concern, and copper or gold wires imported from Earth need to be as thin and light as possible.

External References (Mostly on wikipedia)

  1. ↑ Electrical Resistance
  2. ↑ Electrical Conductor
  3. ↑ Frequency
  4. ↑ Electrical Impedance
  5. ↑ Alternating Current
  6. ↑ Direct Current
  7. ↑ Inductive Coupling
  8. ↑ Primary Coil
  9. ↑ Secondary Coil
  10. ↑ Transformers
  11. ↑ Voltage
  12. ↑ Magnetic Field
  13. ↑ Radio Frequency
  14. ↑ Electro Magnetic Interference
  15. ↑ Electromagnetic Compatibility
  16. ↑ Skin Effect
  17. ↑ Fluorescent Lights
  18. ↑ High Tension
  19. ↑ Electric Power Transmission
Electric Field

Pros

Clean-Sheet Design

This design is not tied to 19th century technological or political considerations.

Cons

Incompatible with Terrestrial Systems

Terrestrial products will require adaptation to work on a power grid using this specification.


Changes

There have been no changes to this specification

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