THE CLIENT
An industrial plant with multiple medium-voltage generator sets connected to the public grid.
THE NEED
The customer’s need was to limit the short-circuit contribution towards the DSO grid.
When a generation plant is connected to the distributor (DSO) network, the short-circuit current that can flow towards the public grid in the event of a fault becomes a critical safety and power-quality parameter.
If the contribution from the customer’s generators is too high, the DSO protections may no longer be adequate and the connection may not be accepted or may require costly grid-side upgrades.
OUR SOLUTION
Based on network specifications, generator data and the limits imposed by the DSO, Ortea technicians developed a medium-voltage current-limiting reactor with the following key characteristics:
- Reactor rated power: 181 kVA
- Rated voltage: 10 kV
- Rated current: 80 A
- Inductance: 30 mH
- Short-circuit impedance: 13% @ 50 Hz
- Voltage drop at rated load: ~750 V
- Associated load power: 1400 kVA
The construction is air-core, with aluminium windings, a choice that ensures stable performance over time, mechanical robustness and good handling of electrodynamic stresses in the event of a fault.
From an insulation standpoint:
- Maximum operating voltage: 12 kV
- Power-frequency withstand voltage (1 min): 30 kV
- Lightning impulse withstand voltage (BIL): 75 kV
- Insulation and thermal class: H, with permitted temperature rise of 125 °C
The reactor is VPI-impregnated (dry), suitable for indoor installation in IP00 execution, with environmental class E1-C1-F0 and maximum operating altitude of 1000 m.