Some electrical comments

[gar]

120703-1922 EDT

We are about 4.5" short on rainfall this year. Have had very few storms, and even many fewer with lightning. We are presently running hot weather, daytime usually into the 90s over the last week.

Under normal conditions the three phase voltage at my son's shop is about 240 V +/-2 V on all three phases. This is a two transformer Y primary and open delta on the secondary with a wild leg. Means one large transformer with a center tap to provide 240/120.

Last week in the middle of the day a fire occurred in the substation completely destroying it.

A number of hours later power was re-established.

A day or so later my son noticed that the 120 circuit was running about 110 V. Now it is more in the 107 to 108 range and UPSs click on and off.

I had him check the 3 phase voltages. These were about 240, 236, and 220. Called Edison over the weekend and they finally arrived today. Today is when my son learned that the substation was completely destroyed, and that a patch was made into another substation about 1 mile away. It is going to take about 13 weeks to replace the burned out sub.

The Edison servicemen agreed there was a problem and they have to get power quality out to look for and find the problem. I suspect the servicemen checked the voltage at the sub now supplying power.

Two strange items.

In the past we have been told that the substation had more capacity than necessary for its load, and prior problems we had were likely the line from the substation. It turned out that out our prior real problem was aluminum wires terminating at the transformer secondaries were arcing.

Second, in a system as large as Edison why don't they have spares for the substation? About 2,000,000 customers and many very large industrial customers.


Other information gleaned from the servicemen. They do not like the new smart meters being installed. Apparently many problems. They opened one and found what was described as a small solenoid. My guess this relates to the disconnect contactor. Another comment was that it looked cheaply made.

How do you pack a quality contactor into a package the size of an old meter and have it work reliably with a 200 A rating?. It could be this is mechanically latched and that could account for a small solenoid size. This may also relate to reports of fires in these meters.

.

 

[mivey]

Second, in a system as large as Edison why don't they have spares for the substation? About 2,000,000 customers and many very large industrial customers.

I'm sure they do have spares: transformers and portable substations. As for the spare equipment: it does not help if the infrastructure supporting it is on the ground. As for the portable substation: If they can make do without it, they will.

Other information gleaned from the servicemen. They do not like the new smart meters being installed. Apparently many problems. They opened one and found what was described as a small solenoid. My guess this relates to the disconnect contactor. Another comment was that it looked cheaply made.

The type meter was probably more of a management decision than an engineering/technician one.

How do you pack a quality contactor into a package the size of an old meter and have it work reliably with a 200 A rating?. It could be this is mechanically latched and that could account for a small solenoid size. This may also relate to reports of fires in these meters.

As you know, you get what you pay for and you and I have seen this with cheaper components. Consider the extreme: One of these for NASA would be a lot more durable but a lot more expensive.

 

[K8MHZ]

Right now it may be possible that most of Edison's resources are tied up in VA and the DC area. Crews from Hydro One in Quebec all the way down to TXU in Texas are going in to work on the damages from a huge derecho laden storm. There are still nearly 1,000,000 people and businesses without power.

I just had a HO call in a 'fluctuating voltage' complaint which usually gets a POCO truck out in less than an hour. It took over 24 hours this time.

 

[kwired]

Mechanical things do fail, designers do make mistakes, installers and maintenance can make mistakes, then budget decisions can really compromise something that was already going to fail.

 

[Hv&Lv]

120703-1922 EDT



Last week in the middle of the day a fire occurred in the substation completely destroying it.

A number of hours later power was re-established.

A day or so later my son noticed that the 120 circuit was running about 110 V. Now it is more in the 107 to 108 range and UPSs click on and off.

I had him check the 3 phase voltages. These were about 240, 236, and 220. Called Edison over the weekend and they finally arrived today. Today is when my son learned that the substation was completely destroyed, and that a patch was made into another substation about 1 mile away. It is going to take about 13 weeks to replace the burned out sub.

The Edison servicemen agreed there was a problem and they have to get power quality out to look for and find the problem. I suspect the servicemen checked the voltage at the sub now supplying power.

Two strange items.

In the past we have been told that the substation had more capacity than necessary for its load, and prior problems we had were likely the line from the substation. It turned out that out our prior real problem was aluminum wires terminating at the transformer secondaries were arcing.

Second, in a system as large as Edison why don't they have spares for the substation? About 2,000,000 customers and many very large industrial customers.

Takes time to clean up and start over. We have 1 spare sub XF, and two mobile subs that are shared throughout the state. They probably do have a spare substation XF laying around, but as mivey stated, the infrastructure is probably laying on the ground ready for the scrap heap. I thought 13 weeks sounded tight actually.
You can't afford to keep an entire substation with all the needed components just waiting for a snake or something to destroy a station.
You tube has some substation fires :
http://www.youtube.com/watch?v=Ux0TeP7oufU&feature=related

http://www.youtube.com/watch?v=xu3RntBy7QA

 

[bob]

The problem is that the substation from which your son is receiving power is too far away. The problem could be easily solve by temporarily installing a set of pole mtd regulators to boost the voltage. That will probably never occur to them. Perhaps a large volume of complaints might engage their brain.

 

[bob]

The problem is that the substation from which your son is receiving power is too far away. The problem could be easily solve by temporarily installing a set of pole mtd regulators to boost the voltage. That will probably never occur to them. Perhaps a large volume of complaints might engage their brain.

 

[Hv&Lv]

The problem is that the substation from which your son is receiving power is too far away. The problem could be easily solve by temporarily installing a set of pole mtd regulators to boost the voltage. That will probably never occur to them. Perhaps a large volume of complaints might engage their brain.

I'm sure it has been thought of, but regulators are like transformers. They are KVA rated. Most specs say that any over 4K lbs. have to be rack mounted. That is 200 kVa and above. The pole has to be a certain class, so it would probably need changing, and the pole has to be "clean", meaning not other stuff on it like transformers or taps. Pole mounting regulators this small on a system that large is sort of like spitting in the ocean...

For 13 weeks of work, a platform bank will probably be built, but there again if the fire has just happened they are probably still weighing all the options.

 

[bob]

I'm sure it has been thought of, but regulators are like transformers . They are KVA rated.

Not so. A transformer rated at 200 kva can only handle 200 kva with out overload. A 200 kva regulator can handle
2000 kva with 10% regulation. The amperage is what really counts.

Most specs say that any over 4K lbs. have to be rack mounted. That is 200 kVa and above. The pole has to be a certain class, so it would probably need changing, and the pole has to be "clean", meaning not other stuff on it like transformers or taps. Pol e mounting regulators this small on a system that large is sort of like spitting in the ocean...

This will depend in the company specifications. You may be correct and you may not.
The ocean is not getting low voltage. You are. Having not seen the system, I can not argue whether this is a solution or not.
If I had people with this service for 13 weeks I would certainly be doing some thing to correct the problem.

 

[Hv&Lv]

Not so. A transformer rated at 200 kva can only handle 200 kva with out overload. A 200 kva regulator can handle
2000 kva with 10% regulation. The amperage is what really counts..

Very well, I didn't know we were splitting hairs. You load a 200 kVa regulator to 2000 kVa with voltage fluctuations like the ones on a distribution line. Let me know how long it takes it to be overloaded.:thumbsup:

This will depend in the company specifications. You may be correct and you may not.
The ocean is not getting low voltage. You are. Having not seen the system, I can not argue whether this is a solution or not.
If I had people with this service for 13 weeks I would certainly be doing some thing to correct the problem.

Cool down, the people have not been experiencing this problem for 13 weeks. what has it been? 1 week now? Think of the people in Virginia that have no power 1 week later. These things take time. Maybe they aren't as perfect as you are. It is easier to judge sitting outside the fence than actually playing the game.

 

[bob]

Very well, I didn't know we were splitting hairs. You load a 200 kVa regulator to 2000 kVa with voltage fluctuations like the ones on a distribution line. Let me know how long it takes it to be overloaded.:thumbsup:

I did not think the difference between 200 and 2000 was splitting hairs. Apparently you do not have a clue how the regulators are rated.Perhaps some Mfg information will enlighten you.








You can say thanks for the education. I assume you can take the amperage x the voltage from the table and get the KVA.

Cool down, the people have not been experiencing this problem for 13 weeks. what has it been? 1 week now? Think of the people in Virginia that have no power 1 week later. These things take time. Maybe they aren't as perfect as you are. It is easier to judge sitting outside the fence than actually playing the game.

I believe it was you that said this situation was going to last 13 weeks. No one mentioned being perfect, just very knowledgeable.

 

[kwired]

Local community recently commissioned a small power plant that uses bio-diesel as the energy source. The #1 reason for the plant was to reduce demand charges from wholesale power suppliers, second reason was it is standby power should transmission lines fail. About a week ago whole town was without power for about an hour - nothing related to the generator - problem with a breaker in the distribution system. Most of general public has no understanding of what is going on and had nothing but complaints about how much was spent on this generation plant and the fact they were without power for about an hour.

They need to understand if transmission is disrupted in a way that it takes weeks to restore, that one hour to get things running again because of a local small problem is really no big deal at all.

 

[Hv&Lv]

I did not think the difference between 200 and 2000 was splitting hairs. Apparently you do not have a clue how the regulators are rated.Perhaps some Mfg information will enlighten you.

You can say thanks for the education. I assume you can take the amperage x the voltage from the table and get the KVA..

I want to thank you for the education on regulator ratings. I was under the impression that the regulators were rated for 10% of the total load. Little did I know that they were actually good for 10 times the ratings and could regulate the entire load. Now I see that utilities all across America have been wasting money buying regulators of different sizes. According to what you have stated and shown me, we could buy only 100 kVa rated regulators and use them everywhere, since, according to you, they are rated improperly and can regulate 1000 kVa of load. No need to buy 333kVa or 667kVa for substations anymore.

I believe it was you that said this situation was going to last 13 weeks.

No, it was Gar in post #1:thumbsup:

 

[bob]

I want to thank you for the education on regulator ratings. I was under the impression that the regulators were rated for 10% of the total load. Little did I know that they were actually good for 10 times the ratings and could regulate the entire load.

Not all the time. If you actually took time and looked at the tables, you will see that the regulator amperage goes up as the % regulation goes down. So if you can get by with 5% regulation rather than 10% the regulator can carry additional load.

Now I see that utilities all across America have been wasting money buying regulators of different sizes. According to what you have stated and shown me, we could buy only 100 kVa rated regulators and use them everywhere, since, according to you, they are rated improperly and can regulate 1000 kVa of load.

I never made that statement. Its something you dreamed up because you did not have the background to understand what I was saying. You were sounding as if you had learned something until you made that statement. Apparently you did not realize that the regulator size depends on the substation size. So, a 100 kva regulator would not fit all substations.

No need to buy 333kVa or 667kVa for substations anymore.

No. That's another incorrect statement for you. There are still needs for the larger size regulators. I don't know where your mind drifted too, but we were discussing pole mounted regulators, Not substation regulators.

I want to help you as much as I can, so I found some additional information that was not too complex. I hope you will take time to read it.
Please let me know if this help you.
http://www.powerqualityworld.com/2011/04/step-voltage-regulator-utility.html

 

[mivey]

The problem could be easily solve by temporarily installing a set of pole mtd regulators to boost the voltage. That will probably never occur to them. Perhaps a large volume of complaints might engage their brain.

It seems easy when you are not involved. It sounds simple enough but it really is not just as easy as running around hanging regulators.

I'm sure it has been thought of, but regulators are like transformers. They are KVA rated.

Not so. A transformer rated at 200 kva can only handle 200 kva with out overload. A 200 kva regulator can handle
2000 kva with 10% regulation. The amperage is what really counts.

Regulators are kVA rated. His point about the regulator size and the added weight on the pole was correct. It is a little more involved than just running out and hanging one on a pole. As HV noted, there are many factors, some which he did not even mention.

 

[mivey]

Pole mounting regulators this small on a system that large is sort of like spitting in the ocean...

It would be for the entire system, but would be fine for parts of individual feeders.

 

[mivey]

According to what you have stated and shown me, we could buy only 100 kVa rated regulators and use them everywhere

What he said does not indicate that.

according to you, they are rated improperly

He was wrong in that respect. Your statement about the weight and size was correct. The regulators are rated by the kVA. That is how we spec them and order them. I think he missed the point about weight and was focusing on your spitting in the ocean comment.

you have stated ... 100 kVa rated regulators ... can regulate 1000 kVa of load.

On that point, he was correct.

No need to buy 333kVa or 667kVa for substations anymore.

We generally have 250's and 333's in the sub, but we have put 333's out on the feeder.

 

[mivey]

We generally have 250's and 333's in the sub

For the feeder-regulated ones.

 

[bob]

It seems easy when you are not involved. It sounds simple enough but it really is not just as easy as running around hanging regulators.

I am missing your point. Hanging a regulator is exactly what I am suggesting.
Its not like I haven't done this before. Many times.

Regulators are kVA rated. His point about the regulator size and the added weight on the pole was correct. It is a little more involved than just running out and hanging one on a pole. As HV noted, there are many factors, some which he did not even mention.

That statement depends on the size of the regulator as was pointed out. Unless you are installing very large reg's it is just running out and installing it on a pole. But I can not see the system. I don't know if it is single phase or three phase. Do not know the load. The concept of solving the voltage problems with regulators is valid given the limited knowledge we have.

 

[mivey]

I am missing your point. Hanging a regulator is exactly what I am suggesting.
Its not like I haven't done this before. Many times.

But who says that is easy? You make it sound like we just load one up and go hang it on a pole. It is not that simple. If you think it is, you have been doing it wrong.

Unless you are installing very large reg's it is just running out and installing it on a pole.

Then you are not doing it correctly.

But I can not see the system. I don't know if it is single phase or three phase. Do not know the load. The concept of solving the voltage problems with regulators is valid given the limited knowledge we have.

Absolutely valid. But not easy given the circumstances.

You have 2,000,000 people out and limited resources. You can't just shoot from the hip and say "well this is easy".