Requirement
The distribution grid of the Arsenal de Toulon is one of the largest private grids in France with more than 150 transformer stations.
Because of the obsolescence of certain protection devices and the limitations of the current protection plan, the management sought assistance to successfully complete the work with a view to updating the protection plan for the 10 kV - 50 Hz high voltage grid supplying its site. Moreover, it wished to improve the reactive energy compensation of the network in order to reduce its energy bill.
Realization
Because of the extent of the project for updating the site protection plan, the service was divided into 3 main phases :
- Phase 1 : Study of the existing system
- Phase 2 : Drawing up of solutions for updating the protection plan and the reactive energy compensation
- Phase 3 : Performance of the studies and specification of the works
During the first phase, Capsim modelled the entire grid using ETAP, in such a way as to be able to validate the voltage plan and to calculate the power flows and the default currents, so as to identify the equipment under stress as well as any selectivity problems. The operating configurations on the site were analyzed in order to use the most unfavourable in the various standard calculations. All of the protection adjustments were carried out and controlled against the selectivity curves.
The second phase was based on the conclusions of phase 1 and envisaged various technical solutions to improve the protection plan.
The selection criteria (criticality of the problem, use of the existing communications networks, ability to evolve, complexity, specificity of the solution, capacity to be integrated in the cells and stations, investment cost, etc.) were used to sort and select the technical solutions. CAPSIM then suggested a preferential solution suitable to each problem.
Furthermore, the reactive energy compensation study is treated according to the same principle :
- Summary of reactive power consumption installations from phase 1
- Study of the existing solutions on the market
- Selection criteria
- Selection and description of the solutions applied to the 10 kV electricity grid
In the phase 3, the preferred solution retained following phase 2 is synthesized in order to realize the specification for the improvement works from the protection plan and for reduction of the reactive energy consumption. A schedule of the replacement works for the protection relays, as well as the capacitor banks, was produced so as to anticipate the on-site work phases.
Results
This study has made it possible to identify the equipment under stress, to update the book of adjustments for protection devices on the site and to schedule replacement of protection relays, taking account of the operating constraints of the site.
Example of a potential staging problem for protection devices
