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WOW what a nice review!

Great Job @Mad Dog_2

Three reasons for using DC power links: Reduce losses and line costs on long links (you don't need intermediate substations to compensate for cables), undersea links (cables have high capacitance), and linking systems together that are not synchronous or different frequencies (japan).

How the converter stations operate is another consideration. Most of the converter stations (certainly the older ones) are based on thyristors. These devices can be switched on electronically but rely on reversing current flow to switch off. So they will only work when connected to a working AC system. In many ways they are same as PV and wind turbine inverters that also require a working AC system.

Some of the newer converter stations are based on IGBTs and these can act as a voltage source just like a spinning generator.

The way PV and wind turbines are connected to power grids is becoming a problem with higher levels of penetration and a reducing amount of spinning metal. It does not have to be this way. With modern power electronics "inertia" can be created with the right control strategies.

In some ways the whole renewable strategy seems to be to make connecting thousands of small devices as cheap and simple as possible and let someone else solve the problems this creates.

John

DC is used for a number of the very high power interconnects — including the ones between France and Spain. Problem is, while they can contribute power if needed, they can't do anything to stabilise grid frequency and thus oscillations. Hence… lights out. The problem is being worked on… but nowhere near to practical engineering never mind installation yet.

QUOTE from above:

EBEBRATT-Ed Member Posts: 17,710May 4

LOL. My house was the same way. I only fixed everything so i could sell it. Never had the time to fix my own place but had the time to fix everyone else's crap.

My Response:

Similarly, it is said, "a carpenters house is always unfinished" and " the mechanic wife's car is the last to be repaired"

All the Best,

RTW

Be careful about return ducts in the basement if you have a gas or oil furnace requiring combustion air from that space