What it is and when you need it
Between the approval of the connection and energization there is a stretch that is often underestimated: the pre-commissioning studies. They turn the design into the settings, switching sequences and models that the utility, the transmission owner and the system operator review before allowing the project onto the grid. If they arrive late or incomplete, the energization date moves even when construction is finished.
You need them when you energize a new substation or bay, when you connect a generation or self-generation plant, and when an expansion changes the settings of neighbouring relays. They are part of our engineering design and studies service and the step before field commissioning.
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.
What is included
1. Protection settings and coordination study. Settings of every enabled function, coordination with the network of the owner of the point of connection, and the settings that must change in neighbouring bays. We apply the criteria of our protection coordination study.
2. Review rounds with the network owners and the system operator. We prepare the kick-off information, the list of inputs to request, each version of the study with its checklist and the written answers to every comment, until the final approved version.
3. Energization review. When the case calls for it, we simulate the energization switching:
- Inrush current of transformers, including sympathetic inrush with transformers in parallel, so that the 87T differential and overcurrent elements do not trip without a fault.
- Ferroresonance, possible when an inductive VT or an unloaded transformer is fed through a capacitance, such as the grading capacitors of an open breaker or a cable.
- Switching overvoltages when energizing lines, cables and capacitor banks, when the voltage level or the configuration justifies it.
These electromagnetic transient simulations follow the modelling guide of IEC TR 60071-4 and support the energization procedure.
4. Technical data and models. For generation, we prepare the technical parameters and the RMS and EMT models the system operator requires for the technology, voltage level and capacity (IEEE 2800 where it is adopted).
5. Settings table and switching sequence, ready for the crew that loads the relays and performs the energization.
How we work
The studies are done remotely, with the detailed design, the drawings and the information from the network owners.
- Schedule counted back. We start from your planned commissioning date and build the schedule of studies, submissions and reviews the system operator requires.
- Kick-off and inputs. We prepare the basic project information and the list of inputs to request from the network owners.
- Model and settings. We start from the grid interconnection study model and complete it with the final data of the purchased equipment.
- Versions and comments. We deliver the first version, answer each comment in writing and issue the final version.
- Hand-over to the field. We deliver the settings table and the energization procedure. If a setting changes during testing, we update the study.
What we need from you
- Planned start date of commissioning tests.
- Connection approval and the interconnection study.
- Single-line diagram, protection schemes and detailed design drawings.
- Nameplate data and factory test reports of transformers, breakers, instrument transformers, cables, inverters or generators.
- Make and model of each relay, and CT and VT ratios.
- Protection contacts of the owner of the point of connection.
What you receive
- Settings study in its versions, with the checklist and the answers to comments.
- Settings table per relay, including the neighbouring bays that change.
- Energization report, when applicable, with switching recommendations.
- Parameters and models in the system operator’s formats, when the project requires them.
Why Tiza Group
- Study and test in the same hands: our team also performs protection testing and energization, in Colombia or elsewhere on request, so settings are calculated with the tests in mind.
- Medium, high and extra-high voltage, in substations, industry and solar plants.
- Settings that reach the relay: we load them on site or through remote relay configuration.
Have an energization date? Tell us about the project and we will build the study schedule.