Is it time to ask UKPN to consider if HVDC works better in future networks ?

Ok this is perhaps a sketch and thinking about what is possible , the final thing may well be quite different and of course we are missing some key yes or no technologies as to what is technically possible and generating in DC.

in terminology terms , transmission refers to means of transmitting electricity to the point of Distribution which is where all the different uses and loads are done , primelary transmission is concerned with carriage of electricity from generation to distribution. The main problem of electrical transmission systems over time , is that generation outputs have increased which in turn has led to problems in how to deal with these high outputs at distribution. In the 1990s materials became possible to insulate specially designed HVDC and HVAC systems , it is not disputed that higher voltages enable more power to be transmitted via a cable and that HVDC has considerable advantages over HVAC over distances.

The advent of the high output wind array , hydro or solar array led to a need for cabling to allow collection and collation of the various units of generation into a single or duel cable system  , to give a neat high output point of exit from generation to then transmit or merge with grid systems , which in itself has required some great work by electrical engineers.

Compatibility is always a problem and large amounts of electrical energy is wasted where this isn't thought through , Imbalances have further problems and once out of operational specifications imbalances can be catastrophic, so as any good engineer should tell you , specification and operational running all need a lot of thought , particularly where such electrical quantities are large and possibly centralised .

The transmission system as a transmission grid has the same advantages as separate circuits , if a generation unit fails , then generation to a common transmission system "should" mean that the demand is not affected in operation , equally failure of a demand "could" suddenly give a problem of overgeneration . Electrical flows in national systems are never static and the balances are always in lag or forward to within the parameters of the equipment and materials.

Is there a perfect system ? well yes and no .If you could make the demands vary less in theory you could match generation much more smoothly and specify equipment where the losses are less , the ideal system in my own thinking is similar to the idea of a constantly variable transmission system , where generation rises and falls in sympathy with demands , however perhaps only in very few situations can this sort of efficiency be achieved in real life.

The advent of the very large battery poses another technical possibility which may suite some thinking , where an HVDC transmission system is used in that a battery can balance demands in a very different way , batteries are DC technology requiring inversion to AC for distribution. If electric car vehicles are using DC then it does seem a bit of problem to be converting from AC to DC via rectification (as in the current system)  or in any future system from  HVDC to AC , the numbers are important the electric car could be consuming around 4-5000MW a day if all fossil fuel cars are replaced , losses of 7% from point of generation to connection to car battery don't seem unreasonable (they are more) but 450MW a day is a lot .

In cost terms when we start thinking about networks from the interconnector , we can see all sorts of different thinking and infrastructure and as nice it is to contemplate if we could relay and rewire all the losses out of the system I doubt , the disruption and cost would make most spending projections easy to put together . But none the less the efficiencies are there.

some of the more interesting future possibilities are around superconductors and perhaps graphene , in terms of voltage losses , however any large bit of electrical infrastructure that is overcomplex becomes a weak point , and engineers now have to think about the future engineers renewing or replacing what has been commissioned now as electricity is and in the future will be (I think) the main form of energy use.


NJK has recently announced a 650kv HVDC cable using its XPLE insulation , it uses copper or aluminium conductor and the breakthrough since the 1990s has been in quality of insulation and manufacturing process quality , 50yrs ago cable quality was limited by process .

The 525 KV cable has been around for a while and cant transmit 2600MW , the 650kv cable can transmit 3000MW and work is already being done on 700kv .The 650kv at 70oC operating temperature starts to suggest some sort of limits and they are designed as submarine cables (being cooled by the water) for large wind arrays . Given Siemens is speculating the 14MW wind turbine is in design  and GE Halide 12MW turbine under going tests , the cable specifications had to catch up !!!

None insulated cables are of course the large overhead transmission systems we see , using aluminium conductors for weight and cost saving . 

The future demands (depending on how generations systems are thought about)  if we do things like local large scale water electrolysis will be very different , and in some ways resolving energy sources for different aspects has to be worked through , as powering everything electrically may not be a good idea .

Converting DC to AC at MW scale has been achieved and it will be perhaps here where the next frontier of heavy electrical engineering will be , transformer efficiency for AC systems has been achieved at 99% , so as transformers are replaced we can recover some of the system operational efficiencies , however (and this real speculation of interest to mathematical modellers only!)  I am wondering if we could supply to individual properties as HVDC and have a circuit for car charging as DC and an individual , 99% efficient , super reliable transformer (and some way of metering) .

Hopefully that gives some aspects of the thinking

Ok this is perhaps a sketch and thinking about what is possible , the final thing may well be quite different and of course we are missing some key yes or no technologies as to what is technically possible and generating in DC.

in terminology terms , transmission refers to means of transmitting electricity to the point of Distribution which is where all the different uses and loads are done , primelary transmission is concerned with carriage of electricity from generation to distribution. The main problem of electrical transmission systems over time , is that generation outputs have increased which in turn has led to problems in how to deal with these high outputs at distribution. In the 1990s materials became possible to insulate specially designed HVDC and HVAC systems , it is not disputed that higher voltages enable more power to be transmitted via a cable and that HVDC has considerable advantages over HVAC over distances.

The advent of the high output wind array , hydro or solar array led to a need for cabling to allow collection and collation of the various units of generation into a single or duel cable system  , to give a neat high output point of exit from generation to then transmit or merge with grid systems , which in itself has required some great work by electrical engineers.

Compatibility is always a problem and large amounts of electrical energy is wasted where this isn't thought through , Imbalances have further problems and once out of operational specifications imbalances can be catastrophic, so as any good engineer should tell you , specification and operational running all need a lot of thought , particularly where such electrical quantities are large and possibly centralised .

The transmission system as a transmission grid has the same advantages as separate circuits , if a generation unit fails , then generation to a common transmission system "should" mean that the demand is not affected in operation , equally failure of a demand "could" suddenly give a problem of overgeneration . Electrical flows in national systems are never static and the balances are always in lag or forward to within the parameters of the equipment and materials.

Is there a perfect system ? well yes and no .If you could make the demands vary less in theory you could match generation much more smoothly and specify equipment where the losses are less , the ideal system in my own thinking is similar to the idea of a constantly variable transmission system , where generation rises and falls in sympathy with demands , however perhaps only in very few situations can this sort of efficiency be achieved in real life.

The advent of the very large battery poses another technical possibility which may suite some thinking , where an HVDC transmission system is used in that a battery can balance demands in a very different way , batteries are DC technology requiring inversion to AC for distribution. If electric car vehicles are using DC then it does seem a bit of problem to be converting from AC to DC via rectification (as in the current system)  or in any future system from  HVDC to AC , the numbers are important the electric car could be consuming around 4-5000MW a day if all fossil fuel cars are replaced , losses of 7% from point of generation to connection to car battery don't seem unreasonable (they are more) but 450MW a day is a lot .

In cost terms when we start thinking about networks from the interconnector , we can see all sorts of different thinking and infrastructure and as nice it is to contemplate if we could relay and rewire all the losses out of the system I doubt , the disruption and cost would make most spending projections easy to put together . But none the less the efficiencies are there.

some of the more interesting future possibilities are around superconductors and perhaps graphene , in terms of voltage losses , however any large bit of electrical infrastructure that is overcomplex becomes a weak point , and engineers now have to think about the future engineers renewing or replacing what has been commissioned now as electricity is and in the future will be (I think) the main form of energy use.


NJK has recently announced a 650kv HVDC cable using its XPLE insulation , it uses copper or aluminium conductor and the breakthrough since the 1990s has been in quality of insulation and manufacturing process quality , 50yrs ago cable quality was limited by process .

The 525 KV cable has been around for a while and cant transmit 2600MW , the 650kv cable can transmit 3000MW and work is already being done on 700kv .The 650kv at 70oC operating temperature starts to suggest some sort of limits and they are designed as submarine cables (being cooled by the water) for large wind arrays . Given Siemens is speculating the 14MW wind turbine is in design  and GE Halide 12MW turbine under going tests , the cable specifications had to catch up !!!

None insulated cables are of course the large overhead transmission systems we see , using aluminium conductors for weight and cost saving . 

The future demands (depending on how generations systems are thought about)  if we do things like local large scale water electrolysis will be very different , and in some ways resolving energy sources for different aspects has to be worked through , as powering everything electrically may not be a good idea .

Converting DC to AC at MW scale has been achieved and it will be perhaps here where the next frontier of heavy electrical engineering will be , transformer efficiency for AC systems has been achieved at 99% , so as transformers are replaced we can recover some of the system operational efficiencies , however (and this real speculation of interest to mathematical modellers only!)  I am wondering if we could supply to individual properties as HVDC and have a circuit for car charging as DC and an individual , 99% efficient , super reliable transformer (and some way of metering) .

Hopefully that gives some aspects of the thinking