What it is and when you need it
A grid interconnection study shows that the network can take your project without exceeding voltage, loading and short-circuit limits, and proposes how to connect it. It supports the technical viability of the connection alternatives of a load, a generation plant or a storage system.
Its scope depends on the size of the project and on who reviews it: a full study for large loads and for generation connected to transmission or sub-transmission, and a reduced study or design review for smaller loads and distributed generation. Requirements depend on each utility and system operator; we adapt the work to the local grid code and to the requirements your utility gives you.
It is part of our engineering design and studies service and comes after the interconnection feasibility request.
What is included
For a full study we typically cover:
- Network model of the area of influence, with approved expansions and the quality, reliability and security criteria of the grid code that applies.
- Connection alternatives, compared on technical grounds.
- Analysis horizon from the in-service year onwards, with the dispatch and demand scenarios published or requested by the system operator.
- Steady state and contingencies: load flow per scenario, year and alternative, with equipment loading against emergency ratings, voltages against the applicable limits, losses and N-1 contingencies.
- Short circuit per IEC 60909 (or IEEE 551 practices for US-based projects): the project’s contribution to faults and comparison with the interrupting capacity of nearby substations. For solar and wind plants, the short-circuit ratio (SCR) at the point, or WSCR or CSCR when several plants are close.
- Transient and dynamic stability: voltage, frequency and rotor angle, with the recovery times required by the grid code. For inverter-based plants, ride-through and reactive support as required by the grid code or IEEE 2800.
- Substation space and layout check: bays used and reserved, conceptual layout and control and protection needs.
- Power quality, when the utility asks for it: harmonics and voltage fluctuations of special loads.
For smaller loads and distributed generation, the scope follows the utility’s technical standard (IEEE 1547 where it is adopted).
How we work
We do it remotely, for projects anywhere.
- Scoping meeting. We review the feasibility answer or the published network information, and what the reviewer will ask for.
- Network data. We ask the utility or transmission owner for the data of their system, or use what they publish.
- Model and simulations. We build the model in tools such as DIgSILENT PowerFactory or ETAP and run the scenarios and alternatives.
- Report. We deliver the report with readable results per scenario and the recommended alternative, in the reviewer’s formats.
- Comments until approval. We address the comments of the utility or transmission owner within the same study.
What we need from you
- Project description: capacity, technology, requested point of connection and planned in-service date.
- Feasibility answer or published network information, if you have it.
- Nameplate data or datasheets of transformers, generators, inverters, cables and lines.
- Site location.
- For solar or wind generation, the primary resource information the reviewer requires.
- The utility’s technical standard, if connecting to distribution.
What you receive
- Interconnection study report with the recommended alternative.
- Annexes for steady state, contingencies, short circuit and stability, with tables in Excel.
- Substation space check, when applicable.
- Documented answers to the reviewer’s comments.
Why Tiza Group
- From study to energization with one team: the interconnection model is the basis for the protection coordination study and the pre-commissioning studies, with nothing redone.
- Medium, high and extra-high voltage, for industrial loads, substations and generation plants.
- Remote, wherever the project is.
Need the interconnection study for your load or plant? Tell us about the project and we will propose the scope.