History of Solid State Breakers

[jimgineer]

This is more geared towards the electrical power engineers who might know... Given that in the grand scheme of things, ICs and the digital age is a relatively new thing, and from my own experience, it seems that solid state breakers with removable trip units and plugs are a new item in power engineering. I was hoping that someone would take a stab at identifying a bit of how they developed and how recently they have become mainstream.

It still seems like price wise there may be some headway left to make, but from my field experience from what I can tell, it seems as though a modular design on a separate trip unit is maybe something that has happened in the last ~40 years, although it looks like the original trip units were either analog or electromechanical. The existing trip units that are popular nowadays are probably just a CT into an ADC into a controller, and then signal out to trip the breaker. But this is one of the few fields electrically, that was already firmly in place and established before the advent of digital. In other words, one of the few fields where digital did not lead the way, but it is still an electrical field. There's a few others that come to mind, (things that involve electromagnetics: radar, imaging, etc), but few and far between. Power distribution strikes me as a large scale endeavor that is very dependent on a lot of knowledgable people to design and maintain but it's also a very slow moving field, it seems. Big investments in infrastructure mean heavy planning and slow moving standards, compared to say, fabless IC design.

It's doubtful many of the power gurus will be around here but I wasn't sure if this should be in there or in the history section. Thanks

 

[Zogzog]

The 1st "electronic" trip units showed up in the early 70's, Westinghouses Amptector and Siemens Static Trip models were some of the first ones to show up, they were very unrelable and still had many mechanical parts that would be damaged by dirty environments. The 1980's brought some improvements (ABB's power sheild, Seimens STII) but mostly still using analog signals, expensive and few options for programming or changing curves and features. The 1990's brought the modern digital trip units, Seimens STIII, ABB MPSC, GE's MVT+ and C-H digitrips. All pretty good units but still some problems.

There are some very good retrofit units available from many different manufactures, URC's AC PRO is all digital, no moving parts, many different programable trip functions and costs a fraction of the OEM's retrofit kits.

Thats just some basics off the top of my head, I can give more exact dates if you want, but it will take a while to compile all the dates.

Do you have a more specific question?

 

[jimgineer]

That's exactly the kind of information I am looking for!

How about SCADA systems? How about generators? I would love more information on approximate market size, any/all big players in the market (and history of mergers, deaths, etc). I find all of this very interesting.

It's tough to imagine a world without certain things, but in the grand scheme of things, it wasn't very long ago that we didn't have a laundry list of things that we take for granted nowadays. Pretty cool time to be alive, and to be an engineer, in my opinion.

 

[SubDesignEng]

what are the questions you have about SCADA and generators? ABB recently acquired Kuhlman Electric, who is a transformer manufacturer in Crystal Springs, MS. I don't know alot about solid state breakers. I would definitely like to expand my knowledge on the subject.

 

[jimgineer]

A lot of questions.. Mainly just trying to get information at this point. I don't know who provides SCADA services, and is it typically a design build field? In other words, does the manufacturer of the control/scada system also provide the engineering design to make the thing work? Or is it like other fields where engineers specify certain systems but are contracted separately for their design? What manufacturers are present? What are the big applications for scada systems? I understand they are used a lot in substations as well as anywhere where process control and monitoring is used. I was at a steam generation plant in DC where they had a neat system set up, but that was the extent of what I knew about it. One of the big things I'm trying to understand is where the line is between a power engineer and a controls engineer is. I have worked now for a consulting firm where we would not mess with some of the details and much of the controls was delegated to others (it seemed to me to almost be a bit dumbed down engineering - focusing mainly on the distribution, producing drawings etc). When it came to actually controlling the standby generators, or any other building automation systems, etc, I wasn't aware of our firm actually doing any of that work. I could have been wrong there but I wasn't involved with it. Now with my current company I see that there is an added level of design and such when it comes to a project that has standby generators, switchgear, etc. The consulting firm (let's take a hospital for example) generally needs to know some overall info on the system operation, but they have no idea on any of the 'inside the box' design of how to operate switchgear, or control the generators. They generally just assume that another company is going to take care of that. This seems to be standard practice for hospitals. However, I'm wondering how the industry is set up for power generation projects (for example let's say the design of a coal fired plant) --- there's going to be more of some specialized DCS or SCADA system in play, and in terms of this design, can someone shed some light on more of the business side for these types of projects --- ie who is responsible for what and how it usually breaks down in design.


Concerning the breakers questions I was asking, I have found from my experience in the field and doing coordination studies thus far, that we are not very far removed from a time where things were so incredibly unorganized and I really see where the 'walked both ways in the snow' kind of mindset came from. Looking at older analog relays and the lack of ability to track down information, it's pretty amazing if you think about the layers of inefficiency that have been removed from every field because of the advances in IT and information gathering. What I mean is, for instance take a look at SKM or ETAP software nowadays. Any manufacturer of a solid state breaker or thermal magnetic breaker is going to have information available so that if you see one in the field, you know exactly what it is and can use it. Whereas, I have come across vintage equipment that seems to be right at the edge (or before) the transition to the more modern digital age, and it's very tough to make sense of sometimes.