Re: [EVGRAY] High Voltage DC Transmission System

Body

Hey, Bert, Phil got an instant erection over this!    Toby, Golka only 
dreamed!

On 12/7/2018 6:38 AM, Norman Wootan wrote:
>
> Ole, thank you for the photos of the HV components of the HVDC 
> systems. Take a look at this attachment from Seimens.. These systems 
> are certainly impressive and they have to use huge halls for totally 
> indoor operation at such high potentials ( one million V) vs the old 
> HVAC outdoor yards.
>
> On 12/7/2018 6:28 AM, Norman Wootan wrote:
>>
>> Ole and Fredric Fletcher, pay attention to the polarity and 
>> methodology of transmission of the HVDC.  Remember the articles 
>> regarding the earth ground return problems up in dairy country, 
>> Wisconsin where cattle were being electrocuted by poor grounding 
>> systems in rural electric grid.  I can recite a real life problem 
>> with imposing a potential into the earth on the dealing with ground 
>> return.  One of our Nursing facilities had three seperate buildings 
>> that shared a two pipe chilled / hot water system with buried steel 4 
>> inch lines (supply/ return).   The electrical system was 480VAC 
>> backbone with delta/wye step down transformers which gave a base 
>> 208VAC with center tap ground for 120VAC. The facility operated just 
>> fine for 50 years.  Along came an Electrical Contractor that 
>> installed a new distribution transformer (100 KVA) during an upgrade 
>> to one of the out buildings. After operation for several years the 
>> buried 4 inch steel AC/heating lines developed leaks and sections of 
>> the removed lines showed electrolyitic (galvanic) errosion.  I 
>> discovered that the Contractor had installed a delta/delta step-down 
>> (100 KVA) transformer and grounded one (L-2) of the Secondary 
>> terminals to get a neutral buss common for 120VAC.  A huge NO,NO 
>> cause you had a potential of 230V to earth ground.  The difference in 
>> ground potential between buildings created the galvanic errosion 
>> because there was a ground return current back to the 480/208VAC 
>> backbone in the mains building.  This was a huge lesson on the 
>> problems encountered with relying on earth ground return path.
>>
>> On 12/7/2018 3:58 AM, Norman Wootan [email protected] [EVGRAY] wrote:
>>> https://www.electronicshub.org/high-voltage-dc-transmission-system/
>>>
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