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Secrets of commercial solar grid applications
Wednesday, November 11, 2020
What is a grid application?
A grid application is a formal request to the electrical distributor of the area under consideration asking for permission (in this case) to connect a solar PV system to their network. In this blog we will be looking at the grid application process that is required for the connection to the network of large commercial solar systems.
Why is it needed?
The DNSP’s (Distribution Network Service providers) own the poles and wires and therefore when planning to connect a commercial solar system over 30 kW on the AC side a request must be made to them. This is a requirement Australia wide and is referenced in various Australian electrical standards.
What do they actually need?
The DNSP asks for a variety of documentation concerning the specific customer and site details, equipment used, where it is going, CAD drawings, SLD’s (Single Line Diagrams), functional statements, commissioning plans, protection study and voltage rise calculations.
Who does all the work?
In many cases a business that specialises in grid applications is the way to go but if doing it yourself, make sure you price in your time for processing the application as it can be quite an involved process.
When dealing with the DNSP’s accuracy, attention to detail is of paramount importance. Checking and double checking everything before it is submitted will alleviate a good deal of the stress involved with this process. I will now outline what is required when outsourcing the grid application process to Greenwood Solutions.
Customer & Site Specific Info
Ensure you have all the information necessary and have prepared the following documents, they will need to be uploaded:
- Customer Authority to Act Form
- SLD Sketch
- Panel Data Sheet(s)
- Inverter Data Sheet(s)
- Photo of MSB Main Switch
- Photo of Meter
- Aerial View Site Layout (panel, inverter, PVDB, MSB & PoS location)
Contact to Check Details
One of the key things to consider when doing a grid application is proofing the information obtained from the customer and installer.
Whether it be:
- Ensuring customer information is correct (ABN, Company Name, etc).
- System design from point of attachment (POA) to the panels is correct.
- Voltage rise is within allowable 2%.
And so on.
All distributors require a submission either online or via email detailing the install specifics. As a necessity, all grid applications include CAD Drawings.
Voltage rise is of paramount importance because the system MUST adhere to no more than 2%. And this voltage rise must be calculated from the POA, or more specifically the transformer/pillar, to the inverters.
It is best practice to describe to the distributor what is being installed and its functionality. There should be a description of the generator for example:
“The proposed Embedded Generator at x-address, is a 513 kW Grid Connect Solar Array, comprising 1595 x 325Wp solar panels, 19 x 27 kW Inverters with export limiting to be confirmed. The system has been designed and subsequently sized, to offset installation maximum demand, and provide general power savings, along with potential network load shaving.”
In addition should also include:
- Inverter initialization process,
- Remote monitoring functionality,
- Emergency contact information
Description of functionality includes but not limited to the following;
- Monitoring interval,
- Export limiting,
- Secondary protection functionality and settings,
- Inverter power factor
It is best practice to have an in-depth explanation of the protection devices throughout the installation from the MCCB (moulded cases circuit breaker), to theMCB’s (miniature circuit breakers, to the GridSafe (secondary protection board), including all the parameters.
Most distributors require a commissioning plan which can include the CEC commissioning plan but also how the GridSafe board is programmed and how it will be injection tested and the export functionality if applicable.
Product Data Sheets
Important to include all the data sheets of the relevant equipment being used such as: panel, inverters, monitoring
The Generator Deed is Supplied by the distributor for the customer to sign and once both customer and the distributor sign the Gen Deed and it is executed this means the application is finalised. This is typically supplied when connecting to the grid for a feed-in tariff.
Some states have additional requirements such as Queensland where all commercial systems over 30 kW on the AC side need to be signed off by a Registered Professional Engineer of Queensland (RPEQ) and this is an additional cost that must be factored into the budget.
If you have any further questions regarding your grid application process please contact us to discuss, regardless - keep the following in mind:
- Ensure you have all the information and have prepared the necessary documents
- Information from the customer needs to be proofed to avoid any delays
- Voltage rise is important because the system MUST adhere to no more than 2%.
- Some states have additional requirements which incur additional costs.