Requirement
The customer wished to understand the causes of a fault observed on the output of a 15 kV capacitor bank which had caused its removal from service. It also wanted CAPSIM to carry out a reactive compensation study to avoid additional invoicing from its energy supplier.
Realization
The study was carried out in four main phases :
- Harmonic measurements on the main 15 kV outputs and inputs. This phase was performed to avoid harmonic voltages being present on the network and causing heating of the condenser banks
- Modelling of the electrical network using ETAP and associated harmonics study. This phase was to highlight, under the conditions present on the day of the fault, the possible harmonic resonances responsible for the over currents in the capacitor banks
- Study of the reactive compensation. This study was carried out starting with the electricity invoice from the energy supplier and a representative annual power assessment. Then, two main directions of study were followed: the equipment (fixed or regulated bank) and the location in the installation (at the head of the network or close to the consumption units)
Finally, the evaluation criteria were defined to select a suitable compensation solution for the customer's electrical grid: the ability to evolve, complexity, capacity for integration as well as the cost to calculate the depreciation of the device.
Results
This study was used to analyze the observed incident and to validate the principles of reactive energy compensation based on harmonic measurements carried out on site and the calculated harmonic resonances.
Frequency impedance curves calculated during the harmonic study
