Stand Alone Solar Power system design

[sbakana]

Greetings

It is my first day at the forum and would like to thank the opportunity I got to be part of Solar Panel Talk.

I am currently designing a 1MW solar power plant. With that I need relevent directions to come up with specifications and design that can work in a South African context. What kind of equipments and how to rate e.g strings, solar chargers, batteries and etc.

I have tried to do some analysis and found that 178 strings will be required for the output of 1MW when using 240Wp.

Thanking you in advanced

Sibusiso

[Naptown]

I moved this to it's own thread.
I think you are a little light on the # of strings.
What is the max allowable DC voltage on the inverters. This is the limiting factor.
Most of the panels you will find for this application will be about 36 -38 VOC
Once you compensate for low temp the voltage goes up.
So take the chosen module at VOC, compensate for coldest record temperature, Divide the maximum DC voltage the inverters can take by what you came up with for the coldest day. that is how many modules you can put on a string.
Next take overall name plate capacity divide by module wattage this tells you how many modules it will take.
Divide # of modules by # of modules in a string. This is how many strings it will take.
You may need to adjust overall # of modules a bit to make the strings equal.
Batteries are put of the question on a system this large.
You mentioned a 1MW output. What do you mean by this 1 MW annually, 1 MW at peak production, 1 MW per day ?

[sbakana]

Hi

I do not know how can I achieve the DC voltage on the inverter, as I have only have done the Solar panel analysis, and thats why I said i will need 178 strings to achieve a 1MW peak production, and that will mean; 5617.98 W per string, where 24 modules (235W) per string. and that will total a 4256 minimum panels needed for 1MW peak production. The maximum string voltage, that operate at minimum temperature is 987.634 V (probably this can be the DC voltage allowable to the inveter).

Mine is, How should I then determine inverter sizes, as I have 24 modules per string? and how can I determine a storage (battery) in a situation like that, mind you is not connected to the grid. obviously I will need a transformer to step down/up the power from inverter to suite a 50Hz 230V AC to consumers appliances, will also need cables that will withheld the stress outside, as they will be exposed to sun, circuit breakers to break/make, relays to protect overvoltage and earth faults, then mine is, how do I determine the size of all equipments needed for such study and which sofware if possible can assist.

How can I simulate such, speadsheet, software or manual calculations.

Thanking you inadvanced.

[Naptown]

What you are asking is beyond the realm of most here including myself.
You realize you are looking at a project of 8-10 Million $US
With an expected budget that large you should look into hiring an experienced, competent electrical engineer to do this for you.

[russ]

Rich is correct and with a project like that the utility will probably only talk with the engineers - this is a bit out of the DIY range.

[Naptown]

Hi

I do not know how can I achieve the DC voltage on the inverter, as I have only have done the Solar panel analysis, and thats why I said i will need 178 strings to achieve a 1MW peak production, and that will mean; 5617.98 W per string, where 24 modules (235W) per string. and that will total a 4256 minimum panels needed for 1MW peak production. The maximum string voltage, that operate at minimum temperature is 987.634 V (probably this can be the DC voltage allowable to the inveter).

Mine is, How should I then determine inverter sizes, as I have 24 modules per string? and how can I determine a storage (battery) in a situation like that, mind you is not connected to the grid. obviously I will need a transformer to step down/up the power from inverter to suite a 50Hz 230V AC to consumers appliances, will also need cables that will withheld the stress outside, as they will be exposed to sun, circuit breakers to break/make, relays to protect overvoltage and earth faults, then mine is, how do I determine the size of all equipments needed for such study and which sofware if possible can assist.

How can I simulate such, speadsheet, software or manual calculations.

Thanking you inadvanced.

Read the red print.
The batteries will need to operate at almost 1000 Volts
So say 480 2V batteries of say 500AH each
That would give him a 480KW bank.
He should have probably have more like a 10MW bank depending on battery type.
This works out to 20 parallel strings of 480 batteries each or 9600 batteries.
That should keep one or two people busy full time just checking and watering batteries.