I must have somehow missed the part about how the new solid state transformers work.
MY LATER ADDED COMMENTS: I define "solid state" as using semiconductors rather than VACUUM TUBES!
IFF you choose to define "solid state" differently than that, please do provide that definition so that we will be speaking the same language!!
I have specified a whole lot of transformers in my career, and most of them are constructed as SOLID assemblies, with o moving parts. Many of them are encapsulated into a solid block to inprove heat transfer and vibration damage. THOSE units are quite soid indeed.
The one characteristic of all transformers is that they use magnetic fields to transfer energy and power. The only "motion" is the electric current flowing in the windings.

 

Found a whole bunch of information on them. Sounds like taking what is already the front end of any standard switching supply packaging it up to accept much higher voltages in the order of 800V seems made mostly for AI data centers, EV fast chargers. they are bidirectional meaning they can feed excess power back to the grid. they are also used in commercial Solar power grids. So I think they already are taking over in a round about way.

 

A bi-directional (or 4-quadrant) converter by another name.
Interesting for data centers which must squeeze the very last available watt from the grid.

 

So it would see a rather limited and specific use for the Solid-State-Transformer.

 

 

Each have their uses and place in systems.
They're useful on wind turbines to produce a constant output from a wind blade turning at a variable speed as the wind changes. The rotor pitch is changed to get maximum power from the wind resulting in varying speeds generator rpm. These units can change the varying frequency & voltage input to a co constant voltage and frequency output.

But you wouldn't use one to transform 400kV to a lower voltage for use in the grid.
Or even transform up to 400kV?

 

At this point I believe that those folks are speaking a different language that us, and that the words in their language have different meanings.

IN that different language it seems that a "Transformer " is a SYSTEM that accepts one voltage (AC or DC) and delivers a different voltage output (AC or DC). NO DESCRIPTION is provided for the mechanism producing this effect except the word "transformer".
In MY LANGUAGE a transformer is a device that changes AC power at one voltage into AC power at a different voltage. I see that the subtle difference is lost to the folks describing the system.

 

he starts by talking about transformers stepping down from 30kV to low kV then shows substitute unit that works in low kV (both in and out). so what do they do to get from 30kV down to low kV?

 

Use a transformer.

 

HOW THAT stepdown from 30KV to local distribution network levels is able to be done is a very good question indeed!! AND certainly A most appropriate one for this discussion. The very first challenge that I see is that those much higher voltages have atendency to jump several inches to other conductors with no provocation.
Of Course, the step-down is not done in a single step!! THERE ARE POWER SUB-STATIONS! Mostly they are tucked away in the less used corner of a development because they are not really very pretty. Those substations include lightning arrestors, fuses, circuit breakers, and the important step-down transformers. The incoming "quite high" voltage arrives on a smaller style "power line" and leaves atop the utility poles that we are familiar with, just a few thousand volts that feed all of those pole-top transformers in out neighborhoods.

If we could get the attetion of some folks in the "high voltage utility products" business perhaps we could get some education on the topic. NOT that I have any plans for any 50 KV systems, but it is a very good question.

 

he starts by talking about transformers stepping down from 30kV to low kV then shows unit that works in low kV (both in and out). so what do they do to get from 30kV down to low kV?

I know, stupid joke. But could not resist.

 

Use a transformer.

the whole point is to use solid state "transformer" to replace the conventional transformer. if one is to still use conventional transformer, then what is the point in using all the electronics that makes SST? that will only add cost and complexity. so when someone speaks out to the camera, that "time of SST is here" that is the part they should explain first.

 

Certainly it should be possible for somebody who actually knows and understands how some alternative scheme works to provide us with an explanation. While it is entirely possible that there can be some improvements in efficiency, the statement as presented smells like a total fabrication by one who has no clue as to the physics involved in transformer operationor any grasp of even what a transformer actually does.

 

My take on this?
A legitimate transformer is a fully bidirectional device, capable of indistinctly transferring power from P to S or S to P without any modifications.

The SST is nothing but a glorified power converter, which takes a higher input voltage and provides an also higher output voltage. DC in the case of data centers, AC in the case of locomotive applications.
Some marketing wise guy must have come with the catchy name, in order to attract attention and most importantly, money to develop the technology.

 

Certainly S.T. has nailed it!! AND, really, it can transform ALMOST any voltage to ALMOST any other. REAlITY does tend to impose a few limits in some cases.

 

The challenge with specifying transformers is usually in ACCURATELY knowing the requirements. A lot like the challegesin designing most control systems.

 

At this point I believe that those folks are speaking a different language that us, and that the words in their language have different meanings.

IN that different language it seems that a "Transformer " is a SYSTEM that accepts one voltage (AC or DC) and delivers a different voltage output (AC or DC). NO DESCRIPTION is provided for the mechanism producing this effect except the word "transformer".
In MY LANGUAGE a transformer is a device that changes AC power at one voltage into AC power at a different voltage. I see that the subtle difference is lost to the folks describing the system.

Bill:

This usage follows a very traditional pattern in technical terminology. The reasoning is simple:

• Transformers are inductance-based devices using coils and cores
• Transistors and related components are called "Solid State" for the reason you already mentioned
• Transformers have been used in high voltage, high current step-down/up applications
• Newer designs featuring solid state devices, as opposed to typical transformers are offering greater efficiency and replacing those coils of wire and cores in specific applications
• These new designs need a contextual name, and they use solid state devices different from the coils and cores one expects in a "transformer" hence, Solid State Transformer.

Your confusion probably comes from the "solid state" vs. "hollow state" origin of the term solid state. In this case there isn't a pairing like that, instead solid state is used as a description of the internals not a contrast to the transformer's relationship to "solid state".

Language doesn't follow strict logic. Humans use intuitive connections to coin neologisms—it's how talking about stuff works. Sometimes things are named badly but most of the time they are just named without regard to some sort of complete rationale of the sort you seem to feel is needed.

 

There is also a strong western centric bias here as there are parts of the world where a "transformer" is not strictly an inductance device using coils and cores.

According to Copilot:

Western-Centric Bias in the Definition of “Transformer”
The claim that “a transformer is not strictly an inductance device using coils and cores” in some parts of the world reflects a Western-centric bias in how technical terms are defined and disseminated. This is similar to the broader concept of Eurocentrism — the tendency to present Western perspectives, definitions, and historical narratives as the default or universal standard.

How the bias appears
In Western engineering and physics education, “transformer” almost always refers to an electromagnetic device with primary and secondary windings and a magnetic core, designed to change AC voltage levels. This definition is rooted in 19th‑ and 20th‑century Western industrial technology and is codified in English‑language textbooks, standards, and academic curricula.

However, in other regions — for example, in parts of Asia, Africa, and Latin America — “transformer” can also be used more loosely to describe any device that transforms a signal, energy form, or data representation, not necessarily via electromagnetic induction. This could include:

• Optical transformers in telecommunications (signal conversion between media)
• Digital transformers in computing (data format conversion)
• Mechanical transformers in engineering (gear ratios, hydraulic conversions)

These non‑electromagnetic uses are often embedded in local technical traditions, indigenous engineering practices, or non‑Western academic frameworks, but they are less visible in Western‑dominated literature.

Why this is a Western‑centric framing
By presenting the electromagnetic coil‑core definition as the “true” or “standard” meaning of transformer, Western sources implicitly marginalize or erase alternative definitions. This mirrors Eurocentric patterns where:

• Western terminology is treated as universal
• Non‑Western knowledge systems are excluded or framed as “special cases”
• Local innovations are not recognized as part of the global technical vocabulary.

Implications
This bias can:

• Limit cross‑cultural technical communication.
• Reinforce dependency on Western‑produced standards.
• Obscure the diversity of engineering traditions.

Addressing it would involve:

• Documenting and validating non‑Western definitions.
• Including multiple “transformer” meanings in global technical glossaries.
• Recognizing that technical terms can have context‑dependent meanings.

In short, the “transformer” definition you mention is not just a technical nuance — it’s an example of how Western‑centric bias can shape even specialized engineering vocabulary, privileging one historical and cultural context over others.

 

Bill:

This usage follows a very traditional pattern in technical terminology. The reasoning is simple:

• Transformers are inductance-based devices using coils and cores
• Transistors and related components are called "Solid State" for the reason you already mentioned
• Transformers have been used in high voltage, high current step-down/up applications
• Newer designs featuring solid state devices, as opposed to typical transformers are offering greater efficiency and replacing those coils of wire and cores in specific applications
• These new designs need a contextual name, and they use solid state devices different from the coils and cores one expects in a "transformer" hence, Solid State Transformer.

Your confusion probably comes from the "solid state" vs. "hollow state" origin of the term solid state. In this case there isn't a pairing like that, instead solid state is used as a description of the internals not a contrast to the transformer's relationship to "solid state".

Language doesn't follow strict logic. Humans use intuitive connections to coin neologisms—it's how talking about stuff works. Sometimes things are named badly but most of the time they are just named without regard to some sort of complete rationale of the sort you seem to feel is needed.

I am not "suffering confusion"!!!
I AM objecting to the incorrect use of a previously well recognized and understood technical term!
Lazy grammer usage tends to promote confusion among yhose not inside some small circle that uses the wrong choice of words.

There is also a strong western centric bias here as there are parts of the world where a "transformer" is not strictly an inductance device using coils and cores.

According to Copilot:

Western-Centric Bias in the Definition of “Transformer”
The claim that “a transformer is not strictly an inductance device using coils and cores” in some parts of the world reflects a Western-centric bias in how technical terms are defined and disseminated. This is similar to the broader concept of Eurocentrism — the tendency to present Western perspectives, definitions, and historical narratives as the default or universal standard.

How the bias appears
In Western engineering and physics education, “transformer” almost always refers to an electromagnetic device with primary and secondary windings and a magnetic core, designed to change AC voltage levels. This definition is rooted in 19th‑ and 20th‑century Western industrial technology and is codified in English‑language textbooks, standards, and academic curricula.

However, in other regions — for example, in parts of Asia, Africa, and Latin America — “transformer” can also be used more loosely to describe any device that transforms a signal, energy form, or data representation, not necessarily via electromagnetic induction. This could include:

• Optical transformers in telecommunications (signal conversion between media)
• Digital transformers in computing (data format conversion)
• Mechanical transformers in engineering (gear ratios, hydraulic conversions)

These non‑electromagnetic uses are often embedded in local technical traditions, indigenous engineering practices, or non‑Western academic frameworks, but they are less visible in Western‑dominated literature.

Why this is a Western‑centric framing
By presenting the electromagnetic coil‑core definition as the “true” or “standard” meaning of transformer, Western sources implicitly marginalize or erase alternative definitions. This mirrors Eurocentric patterns where:

• Western terminology is treated as universal
• Non‑Western knowledge systems are excluded or framed as “special cases”
• Local innovations are not recognized as part of the global technical vocabulary.

Implications
This bias can:

• Limit cross‑cultural technical communication.
• Reinforce dependency on Western‑produced standards.
• Obscure the diversity of engineering traditions.

Addressing it would involve:

• Documenting and validating non‑Western definitions.
• Including multiple “transformer” meanings in global technical glossaries.
• Recognizing that technical terms can have context‑dependent meanings.

In short, the “transformer” definition you mention is not just a technical nuance — it’s an example of how Western‑centric bias can shape even specialized engineering vocabulary, privileging one historical and cultural context over others.

The prejudice against "western usage" is terribly clear here! I understand that some languages lack words with the same meanings as my native language contains.
Working to randomize meanings of words is not a way to benefit communication of accurate information. Not for anybody.
Accurate and well defined meanings of words are not the enemy to be destroyed to allow freedom of speaking.

There is a very simple way to keep the meanings separated, which is to call the non-electromagnetic devices "CONVERTERS" instead. It even saves writing one letter. AND it is more accurate.