Substation Capacity

You can download the calculator at http://www.hydroone.com/Generators/Pages/StationCapacityCalculator.aspx

Are you suggesting that an "electricity distribution substation" has a generating capacity?

I think he must mean how much electricity could be generated by an air turbine mounted downstream of the distribution substation feeding back into the grid....?

I think we don't know what he means, and I'm not sure he does either.

No not really. The wind turbine is only allowed to produce what its maximum output can be (e.g. 500kW - althought it would rarely, if ever, reach this) as agreed with the distribution operator. What i want to know is whether it is possible to know if the substation can accommodate a say, 500kW wind turbine or higher.

No, the wind turbine would be connecting the substation.

No, the wind turbine (generation) would be connecting to the substation.

Ok apologies if what i said didn't make sense. By adding in about the wind turbine, i think, added to the confusion. What i mean is that every substation has the potential to connect to a certain capacity onto its lines (typically either 11kV or 33kV, depending on the technology's capacity). However, if that substation has reached it capacity, either upgrade works will have to occur to all the renewable technology to connect to the substation, or the renewable technology will have to connect to the next nearest substation with available capacity. Both options are extremely costly.

The generation aspect aside, can you tell me assist me in being able to calculate the substation capacity if relevant information, as mentioned above, is available?

the more you talk the deeper the hole seems to become good luck

This information should be obvious in the substation capacity design and commissioning documentation.

Calculations should not be necessary.

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You will have at most the maximum power your wind turbine manufacturer's operations manual says that it can produce if you have at least the rated wind speed. You did say that you had all of the relevant information. The wind turbine design documents are very relevant pieces of information.

I think the wind turbine example, or the use of a generation station, is confusing people.

Take just the beginning of the original sentence:

Can you tell me how I can calculate available generation capacity at a electricity distribution substation if I have all other relevant information (e.g. max load of previous year, 3ph fault levels, firm capacity (MVA) etc.)?

I think there must be a translation problem, because you are not making any sense....

"A substation is a part of an electrical generation, transmission, and distribution system. Substations transform voltage from high to low, or the reverse, or perform any of several other important functions. Between the generating station and consumer, electric power may flow through several substations at different voltage levels.

Substations may be owned and operated by an electrical utility, or may be owned by a large industrial or commercial customer. Generally substations are unattended, relying on SCADA for remote supervision and control.

A substation may include transformers to change voltage levels between high transmission voltages and lower distribution voltages, or at the interconnection of two different transmission voltages. The word substation comes from the days before the distribution system became a grid. As central generation stations became larger, smaller generating plants were converted to distribution stations, receiving their energy supply from a larger plant instead of using their own generators. The first substations were connected to only one power station, where the generators were housed, and were subsidiaries of that power station."

150 MVA substation....

http://en.wikipedia.org/wiki/Electrical_substation

I'm beginning to believe this is a homework problem and the student is confused.

Now that makes sense.....

Your question OP (joe_ru) seemed perfectly clear and simple to me, and evidently to RAMConsult below who replied below with a professional answer. I would go with RAMconsult's advice.

BIN95 thank you for the comment and online calculator you copied in an earlier message. Have been trying to put something like that together but wasn't sure where to start. Excellent!

RAM_Consult, you're answer is exactly what i was looking for. The aim of the wind turbine is to put the excess capacity back onto the grid. Regarding whether contact with the supplier was made it is on a regular basis. The supplier are actually quite good in the data that they release regarding both the 11kV and 33kV substation capacities (by this i mean they release a lot of data relating to how much extra capacity the substation can take - if 1MW, then 2 x 500kW wind turbine could connect to the network).

I don't think i mentioned, but i work in the renewable industry, mainly anaerobic digestion, which would have the same grid issues as the wind turbine. For a particular anaerobic digestion (AD) site, a grid budget estimate is requested from the grid supplier. This will indicate whether there is capacity at the substation for the AD plant to connect.

I've dealt with half MW wind turbines are they definitely are not easy to hide - they would typically be between 70-80m in height and are typically sited in larger farms where nearby residential buildings are less of an issue.

As i mentioned before, regular contact with the electricity supplier is made and there is quite a good relationship with them. The data they release for every substation includes what i mentioned in my original message. However, i am not qualified as an electrical engineer and am learning as i go. My aim was to find a way of determining whether a given substation could accommodate the AD plant or a half MW wind turbine without the need of contacting the supplier all the time for them to indicate whether there is. The data they release tells me this, but not being an electrical engineer i am not quite sure how to read it yet!

Thank you very much for your reply. It was extremely helpful

Joe,

Thanks for the feedback! It's good to see that you are being upfront with the utility, good relations with them is a key to your successful information exchange. There are many reasons why they are your only reliable/accurate source of load carrying capacity.

Just because you know the size of the substation equipment doesn't tell you about the system supplying it, for example, the station could be oversized to allow for future load growth in the area, but it can't fully utilize that capacity until additional feeder lines are installed.

Additionally, you have no way of knowing how their protective equipment is set, it might be relayed to protect the feeder not the station, and if there is any automatic voltage regulating equipment such as OLTC (On Load Tap Changer) or SVC (Switched/Static Var/Voltage Control) capacitors, your generation will have to be coordinated with it.

Keep up the "Good neighbor policy" with them, they are the only source of information about their equipment/system and any future plans for it.

Alan

I think what u want to know is whether the existing bus bars, breakers switches can handle the additional load coming in due to wind generator being connected to this substation.Am I right?

nesubra, that is exactly what i want to estimate from the data i have at hand. As previously mentioned i am not a qualified electrical engineer and am learning as i go. I know that the data the supplier releases is not exact as it constantly changes and there are other factors to consider. However, it's more of an approximate available load capacity i am hoping to calculate. Is this possible from the data i have available?

As substations don't actually generate, the answer has to be "no, and neither can anyone else".

Joe,

I suggest that you listen in on the conversation(?) going on in the thread next to yours regarding cable size, bus bar size, and making guesses about what all that infers. Although engineers try to answer all questions positively, sometimes the answer is still "No".

Alan

If that is the case, how does the supplier determine the maximum additional power that can be injected into the network from a renewable energy?

The supplier does not make that determination, the owner of the substation does. Although you are pushing for an answer more to your liking, the fact remains that you are going to have accept what they tell you; they know more about their facilities than they will ever share with you.

It's no different than pulling into a gas station and asking for 2 gallons of gas, the supplier says "...but you have a 20 gallon tank...", you say "...but 2 gallons is all I want..."

Ha we're in agreement there. They will only share the bare minimum. I was just looking for a way to figure out if it was possible to get an insight from the data they do release. In this instance the supplier and the substation owner are the same (i.e.the DNO). Thanks very much for your input throughout the thread. It was really helpful.

Joe