WE Energies to Squash Distributed Renewables with their latest rate case.

[ChrisOlson]

I'd like to add some on this problem of balancing three-phase distribution and distributed generation.

The problem the utility faces in balancing their three-phase primary from a substation is not easy when most of the loads are single phase. I was a sawmill yesterday where they have had problems with overheating three-phase motors on utility power. On standby generator power their motors are fine. And there has been brownouts in the area whenever the sawmill is running. I took three photos showing the voltage on one of their motor panels with zero load on their system:







The wild leg being at 217V on this particular day is normal. However, a difference of 3V between L1 and L3 to neutral is not. They should be identical, as that is suspect right there to cause a delta-wired three-phase motor to draw excessive amps on one phase. Start the mill up and put the system under load and the voltage on L1 dropped to 109V.

I drove the lines for 30 miles and found the problem. Back in June the utility had put in two 2400V transformers with a ground and there was a three-wire single phase feeder running off into the brush. End up that it goes to a lake where there is a lake home and resort development project and in the process of wiring up that development they managed to overload one phase conductor on the utility primary. Turn on the sawmill at the end of the line and guess what happens?

The utility COULD use some form of single phase distributed generation at that development site to "fix" the problem. But who's going to pay for it, what type of distributed generation should be used, and how much and how to time it for peak load is an issue where there's too many people and private property owners involved to come up with a solution.

[Sunking]

The problem the utility faces in balancing their three-phase primary from a substation is not easy when most of the loads are single phase.

Hogwash, no utility sub station sees single phase loads, only users see it if they have a neutral conductor needed for single phase loads. Any unbalance of line current is a Fault somewhere in the system. No Industrial or most commercial operations use single phase, they use exclusively 3-phase Delta. If they need a single phase voltage, they derive it from their own transformers for office equipment or anything needing 208/120. Industrial and most commercial applications do not use single phase as it is too dangerous (grounded) and prone to unnecessary outages (again associated with grounded systems). A large user like a Saw Mill will have Delta 69 Kv service, and then step it down to usable voltages, but it is all 3-phase Delta connections to the utility.

Residential distribution is where you will see Wye connected 3-phase, but those transformers setting out on a pole are primary connected Delta so the utility never sees a unbalanced load. Any unbalanced load detected by a utility is a fault and will cause the switch gear to open the line and cut off power. Only way to get an unbalance load on a utility is if something like a lightning strike or one of the phases falling and hitting the ground like from a storm or car accident.

[ChrisOlson]

Hogwash, no utility sub station sees single phase loads, only users see it if they have a neutral conductor needed for single phase loads.

Sunking - I'm pretty sure you must sometimes just Think Stuff Up to argue, without reading about what's going on. Substations are fed with delta-wye transformers and rural low voltage 13.8 and 7.2 kV feeders from the substation are normally three-phase wye with a neutral back to the substation. Take a good long look at the overhead lines - that's why there's four of 'em - three phase conductors and a neutral conductor. Delta distribution uses a ground conductor for lightning protection on top of the three phase conductors. Wye distribution uses three phase conductors on top with the neutral underneath, and the neutral is grounded.

I don't care if the source is wye or delta, you cannot put a single phase load on ANY three-phase distribution and keep it balanced. Period. And anybody that tries to tell that you can does not have a single clue what they're talking about. Unbalanced loads on feeders is what causes the imbalance current to flow back to the substation transformer on the neutral.

The wild leg delta system we have here is supplied one of two ways at the service drops. One is by a transformer having four wires coming out of the secondary - the three phases, plus a center tap neutral on one secondary.

The second requires either two or three transformers, depending on whether or not code allows more than one service on the premises. One or two transformers are connected to one or two phases of the overhead primary distribution to provide split-phase. An additional transformer is connected to third phase on the primary distribution and its secondary is connected to one side of the split-phase transformer secondary, and the other side of this transformer is brought out as the 'wild leg'. The voltages between the three phases are the same in magnitude, however the voltage magnitudes between a particular phase and the neutral vary. The phase-to-neutral voltage of two of the phases will be half of the phase-to-phase voltage. The remaining phase-to-neutral voltage is root 3 times half the phase-to-phase voltage.

You've evidently never worked with the wild leg delta system we have up here and sound like you're only familiar with the balanced 120/208 systems they use in big cities where phase to neutral voltages are all the same.

[ChrisOlson]

Any unbalanced load detected by a utility is a fault and will cause the switch gear to open the line and cut off power. Only way to get an unbalance load on a utility is if something like a lightning strike or one of the phases falling and hitting the ground like from a storm or car accident.

Sunking - you need to read more carefully here. What is being discussed is the feeders from the substation. Up here there will be a 7.2 kV feeder running for 100 miles thru the brush from a substation. The voltage drop on those low-voltage feeders is HUGE by the time you get to the end of the line where the sawmill is. They have a 100 hp motor on the saw table and it draws 300 amps on 240V three-phase (yes, 240V - NOT 120/208 or 277/480, which are both wye systems). They have a soft start on that saw but it browns out 60 miles worth of service drops when they start it, and it never did that until the utility connected another 2.4 kV feeder (single phase) going to the lake development project about 30 miles down the line.

Nobody maintains this stuff up here. They don't even fix broken poles as long as the wires on both sides of the broken pole still hold the pole off the ground so the wires don't touch. When I was driving the line looking for the problem I seen one swamp crossing where the wires are only 6 feet off the water in the swamp because one pole rotted off and another one is leaning. But the poles on both sides of that are still upright and the stretched wires are holding up the failed poles. Won't be long and there will be another power outage for the folks up here, and I know exactly where the problem is.

I put a call into the utility and left a message for the service people that they need to get their asses up here bright and early on Monday morning to switch that feeder to the lake project to a different phase because they got too many drops on that phase conductor. I got a load of logs setting there in the yard and they can't even saw them because they can't run their mill unless they start their generator.

The "grid" isn't quite as well maintained up here as you're used to in your more populated areas. If the power goes out it'll take 3-4 days before they get done drinking their coffee and decide to go fix it. And even then it's cobbled. The next time I drive by it I'll take a photo - but there's one pole that went down about a year ago and landed in a tree and they never did replace it. They propped it back up and got a bunch of planks running from the tree to the pole lag screwed to it, holding it up.

And then the other problem we got is the wind. Where some of these poles are rotted off or busted, when the wind gets blowing the phase conductors start whipping around in a circle like big jump ropes when the poles rock back and forth. Until one finally slaps the neutral conductor. Suddenly everybody's neutrals in their houses is energized to 7,000 volts and it blows sh!t right off their countertops and walls. The sawmill where I take my logs had a 6 AGW Type SOW cable running to the motor on their planer when that happened once. It blew a big hole right thru the jacket on the cable AND the ground conductor going to the motor, then proceeded to burn the phase conductors in the cable just about in two before something tripped and all the power went out. The utility claimed lightning strike (in the middle of winter). Frickin' lyin' bastards. I know exactly where the problem happened because there's a big burn mark on the neutral and it set one of the poles on fire and burned it half up.

[kwilcox]

Sunking - you need to read more carefully here....
...And then the other problem we got is the wind. Where some of these poles are rotted off or busted, when the wind gets blowing the phase conductors start whipping around in a circle like big jump ropes when the poles rock back and forth. ....

That is exactly what my father-in-law was describing when those big T-Storms hit up North in September! Nobody could figure out why the lines were wrapped around each other like that!

[ChrisOlson]

That is exactly what my father-in-law was describing when those big T-Storms hit up North in September! Nobody could figure out why the lines were wrapped around each other like that!

Oh, we got it figured out. They need to put guy wires on the poles or something. I mean there's nothing but swamps and sand and woods up here so it's not like there's good dirt to set poles in. But the stuff that's here is 40 years old. And as people from the Twin Cities have bought little pieces of land and lake property and stuff, they just kept adding loads and more and more service drops until they got a problem.

As it is right now the money is flowing into the shareholder's pockets just fine. And they don't plan on fixing nothing as long as the money flows. Cobble it, patch it, whatever it takes to keep the money coming in without spending anything.

[ChrisOlson]

That is exactly what my father-in-law was describing when those big T-Storms hit up North in September! Nobody could figure out why the lines were wrapped around each other like that!

I don't know if your father-in-law is for or against the iron mine up here in Hurley where Gogebic Taconite wants to build the largest open-pit mine on earth. All the "greenies" and tree huggers and stuff are against it. But iron mining started in Hurley and Mellon in the 1880's and the Great Depression shut it all down. The town of Hurley says bring it on - the sooner the better. They want to be a big bustling mining town again.

Anyway, Gogebic Taconite knows there's not enough power up here to run their mine. They plan on bringing in four 4.0MW diesel generators to power that mine. I'm pretty sure they'll have the largest power plant north of Dairyland Power's Flambeau hydro plant. We're all hoping maybe we can string some extension cords thru the woods and plug in there someplace. Ta hell with renewable power

[kwilcox]

Well, I showed up at the October 8th meeting and gave my impassioned little speech to a packed house. Got clapping and cheering when I mentioned the 20 year transferable grandfather clause too. The moderator had to tell everybody to quiet down lol... Lots of questions afterwards from interested ppl mostly centered around energy storage. Thanks to you guys, I pretty much dashed their immediate hopes.

I guess the saddest part was listening to all the old people on fixed incomes who couldn't come to grips with the fixed facilities charges. One poor guy turned off his main breaker every time he left the house to try to save a few more pennies and was pleading to not raise fixed charges any more. These are the folks getting shafted the most.

However, the commissioners never even showed up. That pretty much punctuates just how little public comment has to do with any of this. The good news is that the Interveners on record are doing a bang-up job. I've got high hopes for an Arizona like decision or even better.

[SunEagle]

Well, I showed up at the October 8th meeting and gave my impassioned little speech to a packed house. Got clapping and cheering when I mentioned the 20 year transferable grandfather clause too. The moderator had to tell everybody to quiet down lol... Lots of questions afterwards from interested ppl mostly centered around energy storage. Thanks to you guys, I pretty much dashed their immediate hopes.

I guess the saddest part was listening to all the old people on fixed incomes who couldn't come to grips with the fixed facilities charges. One poor guy turned off his main breaker every time he left the house to try to save a few more pennies and was pleading to not raise fixed charges any more. These are the folks getting shafted the most.

However, the commissioners never even showed up. That pretty much punctuates just how little public comment has to do with any of this. The good news is that the Interveners on record are doing a bang-up job. I've got high hopes for an Arizona like decision or even better.

Looks like you at least made some headway. I will cross my fingers with hopes that any increase they might get will be very little.

[solar pete]

Well, I showed up at the October 8th meeting and gave my impassioned little speech to a packed house. Got clapping and cheering when I mentioned the 20 year transferable grandfather clause too. The moderator had to tell everybody to quiet down lol... Lots of questions afterwards from interested ppl mostly centered around energy storage. Thanks to you guys, I pretty much dashed their immediate hopes.

I guess the saddest part was listening to all the old people on fixed incomes who couldn't come to grips with the fixed facilities charges. One poor guy turned off his main breaker every time he left the house to try to save a few more pennies and was pleading to not raise fixed charges any more. These are the folks getting shafted the most.

However, the commissioners never even showed up. That pretty much punctuates just how little public comment has to do with any of this. The good news is that the Interveners on record are doing a bang-up job. I've got high hopes for an Arizona like decision or even better.

Thanks for the update kwilcox, I admire your tenacity, good luck and keep up the good fight. So the commissioners never showed up, what a disgrace, did they send apologies or offer a different meeting time?

[kwilcox]

Thanks for the update kwilcox, I admire your tenacity, good luck and keep up the good fight. So the commissioners never showed up, what a disgrace, did they send apologies or offer a different meeting time?

nope. People were pretty incised about it too. There was only a lawyer there representing the PSC to swear people in and a stenographer to take the comments down.

[Sunking]

I don't care if the source is wye or delta, you cannot put a single phase load on ANY three-phase distribution and keep it balanced. Period. And anybody that tries to tell that you can does not have a single clue what they're talking about.

Really? Try again please

three-single-phase-transformers-connected-delta-delta.gif

Sunking - I'm pretty sure you must sometimes just Think Stuff Up to argue, without reading about what's going on. Substations are fed with delta-wye transformers and rural low voltage 13.8 and 7.2 kV feeders from the substation are normally three-phase wye with a neutral back to the substation. Take a good long look at the overhead lines - that's why there's four of 'em - three phase conductors and a neutral conductor. Delta distribution uses a ground conductor for lightning protection on top of the three phase conductors. Wye distribution uses three phase conductors on top with the neutral underneath, and the neutral is grounded.

Rural systems are Multi-Grounded Neutral aka MGN. The Neutral is called Static Ground, and is bonded to earth at least every forth wooden structure like a pole via the Pole Butt Ground, or at every steel structure as required to meet NSC requirements. . Its primary purpose is lightning protection and carries very little normal load current in a Wye system because earth impedance is far lower than a steel conductor ran for 100 miles above earth as you claim.

You are correct rural systems can be fed Wye from a Delta Primary transformer, but the sub-station equipment never sees any unbalance encountered on the secondary distribution. To keep the Wye Portion of the distribution balanced, utilities mix and match load connections to keep the currents balanced as much as possible and they do a fairly good job of it. The utility controls who gets what connected to what phase or phases. But the imbalance is not returning on utility wires, it is returning via EARTH because dirt is cheaper than steel. The only place you are going to see any significant load current on a neutral conductor on the utility equipment if the grounded circuit conductor between the service transformer and your metering called the Service Drop which is going to be likely aluminum.

[Sunking]

Sunking - you need to read more carefully here. What is being discussed is the feeders from the substation. Up here there will be a 7.2 kV feeder running for 100 miles thru the brush from a substation. The voltage drop on those low-voltage feeders is HUGE by the time you get to the end of the line where the sawmill is.

That is silly. A 7.2 Kv feeder for 100 miles huh? Most folks might believe that but that because they do not know what that means or how transformers work.

Distribution feeders run around 100 amps max, in some cases up to 200 to 300 amps. Over head lines utilities use are ASCR (Aluminum Conductor Steel Reinforced). A 100 amp feeder will use Code Trade name Robin a #1 AWG ACSR. Robin has an AC impedance of .268 Ohm's/Kft or 1.39 Ohm/mile. For 100 miles that is 139 Ohms. Worse case scenario If you were to fully load the conductor to 100 amps @ 100 miles away you would loose roughly roughly 140 volts on a 7200 volt line which is 1.9% loss. On a single phase 240/120 service you would expect a maximum 3 volt drop from no load to full load. NESC standard is +/-10%.

You wanna talk a 13.2 line? Cut that loss in half.

[bcroe]

That is about the most ignorant statement you have said on this forum. Really a 7.2 Kv feeder for 100 miles huh? Most folks might believe that but that because they do not know what that means or how transformers work.

Distribution feeders run around 100 amps max, in some cases up to 200 to 300 amps. Over head lines utilities use are ASCR (Aluminum Conductor Steel Reinforced). A 100 amp feeder will use Code Trade name Robin a #1 AWG ACSR. Robin has an AC impedance of .268 Ohm's/Kft or 1.39 Ohm/mile. For 100 miles that is 139 Ohms. Worse case scenario If you were to fully load the conductor to 100 amps @ 100 miles away you would loose roughly roughly 140 volts on a 7200 volt line which is 1.9% loss. On a single phase 240/120 service you would expect a maximum 3 volt drop from no load to full load. NESC standard is +/-10%.

I calculate 100A through 139 ohms (100 miles) drops 13,900 volts.

I don't see how putting the 3 phase Delta through 3 single phase transformers helps balance
phase loads. Bruce Roe

[Sunking]

I calculate 100A through 139 ohms (100 miles) drops 13,900 volts.

I don't see how putting the 3 phase Delta through 3 single phase transformers helps balance
phase loads. Bruce Roe

Well crap, that happens when you figure it in your head and forget to move decimal points.