TVSS's Surge Protection - Good Investment?

[Coachman]

In our area we had a 34,000 Volt line fall on a 12,000 Volt
line and gave us a High Voltage surge for about 1 sec. but enough
to cause a good bit of damage. We lost about 10 Freq. Drives.
I have a few questions that you may be able to answer.

- How are TVSS's, I would imagine that they are good investments.
I am looking at the Mission Critical 300 Series TVSS Units.

- Do you know of anyone recovering any cost from the Power
Companies for damage.

- What about Power Conditioners ,I know they are expensive.We
have alot of short outages,about a sec. or 2. Would a
conditioner stay high enough for 2 sec.that we would be able
to ignore the outage, we would most likely be looking at a UPS

Thanks in Advance,

 

[Lancie1]

How are TVSS's, I would imagine that they are good investments.
I am looking at the Mission Critical 300 Series TVSS Units.

There is a lot of hype surrounding surge arrestors. The basic component is a metal-oxide semiconductor that shunts an overvoltage spike to ground. You could buy the bare-bones MOV's for $4 or $5 each, but most of us prefer a finsihed device with an enclosure, wiring, and perhaps a few LED's to indicate the status of the MOV's. I have bought good surge arrestors for $60, but I have seen so-called deluxe models for thousands of dollars, even though the basic component is exactly the same. Let the buyer beware of hype, cons, and over-blown claims. Paying more does not always mean that you are getting your money's value.

 

[Jiri Toman]

There is a lot of hype surrounding surge arrestors. The basic component is a metal-oxide semiconductor that shunts an overvoltage spike to ground. You could buy the bare-bones MOV's for $4 or $5 each, but most of us prefer a finsihed device with an enclosure, wiring, and perhaps a few LED's to indicate the status of the MOV's. I have bought good surge arrestors for $60, but I have seen so-called deluxe models for thousands of dollars, even though the basic component is exactly the same. Let the buyer beware of hype, cons, and over-blown claims. Paying more does not always mean that you are getting your money's value.

I agree with everything said here 100% !
The basic component, the MOV has to have large enough diameter for the surge you are trying to suppress. Also there is an issue of coordination between the upstream and downstream MOV's.

One of the top experts in the field is Dr Ron Standler
http://www.rbs2.com

He is also an attorney, but has a Phd in physics and has his own lab where he tests variety of TVSS's. You could higher him for about 250 USD / hour. He could design a coordinated system for you that would cost you less in hardware, but there would be a charge for his time. I was very impressed with his level of knowledge.

 

[SitnDuc]

I agree with everything said here 100% !
The basic component, the MOV has to have large enough diameter for the surge you are trying to suppress. Also there is an issue of coordination between the upstream and downstream MOV's.

Actually, I'm going to have to disagree about TVSS's just being hyped up. There's a lot that goes into a TVSS than just MOV's (Metal Oxide Varistors). TVSS technology doesn't just use 1, 2 or a couple MOV's. The good units (and more expensive ones) will use a lot of them. And, they don't just use MOV's. MOV's are sacrificial in nature. Every time they do there job, they are degraded. There are other components to a TVSS that help shunt or dissipate a surge to ground. Having the TVSS circuits encased in potting compound is another feature that actually performs 2 functions. The first, dissipating heat. The second, keeping failed TVSS components from causing more damage due to fire, explosion, etc… Just like your TV would meltdown if you plugged it into a 480v source. A $60 surge suppressor is not the same as a $1000 TVSS. We used TVSS’s in the Navy and they worked great. ROI was in the millions for electronic systems. Before we used them, we conducted independent testing. We subjected the TVSS to 6kv, 3ka 8x20 microsecond pulse every 10 seconds. That lasted for a little over 47 hours continuously (17,000 pulses). The let through voltage after the test had a variance of less than 3% from the baseline (beginning) voltage. A $60 surge protector would not have been able to finish the test nor would a couple MOV’s.



Now, try that same test without any protection. How much do 10 freq. drives cost and the labor to install them? TVSS’s are a good investment; you just have to make sure you do your research and find a manufacturer or distributor with a quality product.



Here’s another example of a TVSS’s worth. We had a backhoe cut into the main power line at an airfield on a Naval Air Station. The equipment rooms in the Ground Electronics building were protected by a TVSS. The TVSS protected the communications and radar systems inside the building (no damage), but the TVSS was fried. Actually the case was deformed but the potting material kept all the components from becoming shrapnel. A $1500 TVSS protected about a million dollars worth of electronic gear. Everything else that wasn’t protected by a TVSS was either damaged or melted.

 

[Jiri Toman]

TVSS technology doesn't just use 1, 2 or a couple MOV's. The good units (and more expensive ones) will use a lot of them.

Yes they do but in fact it does not help. Since MOVs are not exactly manufactured with same precise specs, it is inevitable that one MOV will always fire first. This is what I have learned from Dr Standler, whom we have hired for one day consultation.

Having the TVSS circuits encased in potting compound is another feature that actually performs 2 functions. The first, dissipating heat. The second, keeping failed TVSS components from causing more damage due to fire, explosion, etc

Potting compounds don't protect you from explosion. Again according to Dr Standler, who tests TVSSs in his lab, the key is to have a steel (not plastic) box around the MOV and the ideal fill-in component is the sand!

There are other components to a TVSS that help shunt or dissipate a surge to ground.

These other components, usually low/high pass filters etc. don't really do anything to dissipate the surge. I will be happy to listen to your exact explanation of what these extra components do and exactly what they are? In most cases it's all a marketing ploy to get you spend extra money.

 

[Lancie1]

Jiri,

As that great showman P.T. Barnum supposedly said, "There's a sucker born every minute".

 

[Coachman]

We have it narrowed down to 3 Brands. What is your opinion

We have had 4 companies in to discuss and to look at our application about Surge Suppression. We narrowed it down
to 3. What do you think of the following?

All are 300kA Units accept the Square D that is 320 kA

Mission Criticalgard 300 series TVSS Units

Square D TVS4EMA32AC TVSS Units w/ Surge Counter

Surge Suppression Inc. ( Destin ,Fl.) SMLA3Y2E1

Thanks in advance for your response,

 

[Jiri Toman]

As I have said before claims made by most of the TVSS manufacturer's are stretching the truth. Dr Standler is the only one who could answer your question based on actual scientific data obtained by his testing lab. It maybe worth while for you to hire him for a small consulting fee.

 

[Gil47]

In our area we had a 34,000 Volt line fall on a 12,000 Volt
line and gave us a High Voltage surge for about 1 sec. but enough
to cause a good bit of damage. We lost about 10 Freq. Drives.

When a high voltage line falls onto a lower voltage line, the main effect is arcing that produceses a high frequency, now this high frequency goes looking for something to soak it up, and capacitors love high frequencies and draw lots of current, and may fail in the process, now Freq drives are full of capacitors, hence in this case they were the weak link


In this case a TVSS would probably have saved nothing but itself.

I would like to know what the Power Factor is on your site my guess is 0.8 PF ,
Now for speculation,
( My reasoning is, as power factor correction banks would have soaked up the surge and saved the Freq drives. )


As you have guessed, I'm with Lancie and Jiri.

 

[kamenges]

Jiri-

What did the good doctor tell you in person that he didn't say on his website? He is basically advocating the use of the components in a typical TVSS package. He must have given you something additional that he doesn't say on his website.

So I can pay the good doctor $2000 plus expenses to design me a system that I need to implement myself or I can spend $1000 a piece on a couple of reputable COTS TVSS's and put those in. Sounds like a wash.

Keith

 

[Lancie1]

I have used a Square-D unit in the past and found it adequate. The key for using any surge arrestor is to test it after major surges. Eventually they will fail if the voltage spike is large enough. The surge counter is a nice feature. It should give you an idea of how close you are to failure.