In India, two Odyssey 500-30 electronic stabilisers were installed in a new HV→MV substation to protect auxiliary services. The solution ensures stable LV voltage by mitigating fast disturbances not handled by the OLTC.
POWER QUALITY IN SUBSTATIONS: VOLTAGE VARIATIONS AND MITIGATION
Substations are critical nodes where power and data are transformed and distributed. Here, voltage quality is put to the test by:
- Rapid load variations (motor starts, switching of capacitor/reactor banks, network reconfigurations).
- Transients and sags/swells induced by upstream manoeuvres or faults.
- Long/weak feeders that amplify voltage drops and rebounds.
- Interactions with distributed generation (PV/wind) that introduce rapid fluctuations.
Substation auxiliaries (relays, IEDs, SCADA, PLCs, battery chargers, UPSs, measurements) are sensitive: even short-lived variations can generate false trips or malfunctions. The transformer’s OLTC is excellent in the medium term, but its dynamics are slow; therefore, a fast “downstream” loop is needed.
WHY VOLTAGE FLUCTUATIONS ARE FREQUENT IN COUNTRIES SUCH AS INDIA
Without generalising, in contexts characterised by:
- High load variability (industrial/civil mix, pumps, traction, HVAC) and growth in demand.
- High penetration of renewables with rapid ramp rates (cloud cover over large PV fields, wind gusts).
- Extensive lines and mixed urban-rural networks (higher impedance, more pronounced drops).
- Frequent maneuvers for congestion management.
Voltage fluctuations and surges are more likely. In these cases, an electronic stabiliser with a millisecond response reduces the exposure of auxiliaries to disturbances between OLTC taps.
THE SOLUTION: ELECTRONIC VOLTAGE STABILISER
For the new HV→MV substation under construction in India, we supplied two Odyssey 500-30 units with the aim of stabilising the LV of the auxiliary services and ensuring the continuity and reliability of the protection and control systems.
APPLICATION OBJECTIVE
- To stabilise the 415/230 V voltage of the auxiliary services (protections, IED/SCADA, PLC, UPS, battery chargers) by filtering short-term sags/swells and rapid variations that the OLTC does not intercept in time.
SUPPLY DATA (FOR EACH UNIT)
- Model: Odyssey 500-30.
- Power: 500 kVA.
- Input adjustment range: ±30%.
- Output stability: ±0.5% (rapid electronic adjustment).
- Installed option: 800 A output circuit breaker (protection and isolation).
BENEFITS FOR THE SUBSTATION
- Continuity of auxiliary services: fewer false trips, greater availability.
- Clean and constant voltage: improved reliability of relays/IEDs and measurements.
- Coordination with OLTC: OLTC manages the long term, Odyssey manages the dynamic.
- Reduction of perceived flicker: on sensitive loads.
- Integrated protection: (with 800 A circuit breaker) for maintainability and safety.
ORTEA’S EXPERTISE IN VOLTAGE STABILISERS
Ortea has been designing and manufacturing voltage stabilisers for decades, with:
- Fast-response electronic architectures (semiconductor switching) designed for critical environments.
- Extended range and ±0.5% output tolerance.
- An application-based engineering approach: sizing based on actual disturbance profiles, coordination with OLTC/power factor correction/STATCOM, bypass and protection strategies.
- Functional tests and inspections in accordance with applicable standards, with clear and traceable reports.
Discover Ortea’s range of stabilisers
ORTEA AS A GLOBAL PARTNER
With an international presence and a technical team accustomed to working with utilities, EPCs and OEMs, Ortea supports projects around the world, from requirements definition to commissioning.
The consolidated supply chain and after-sales service guarantee reliable delivery times and local support, even in complex infrastructure contexts.
FAQ
WHAT IS THE DIFFERENCE BETWEEN OLTC AND ELECTRONIC STABILISERS?
OLTC regulates the transformer ratio in a matter of seconds; an electronic stabiliser compensates for sag/swell and rapid downstream variations in milliseconds, maintaining LV within ±0.5%.
WHEN IS AN INPUT ADJUSTMENT RANGE OF ±30% REQUIRED?
When the grid is highly variable (weak lines, high renewable energy penetration, intermittent loads) and stable voltage must be guaranteed for critical loads.
DOES THE STABILISER INTRODUCE HARMONICS?
Ortea electronic models are designed to minimise distortion and comply with PQ limits; sizing includes EMC checks and coordination with filters/power factor correction when necessary.
IS IT COMPATIBLE WITH UPS AND BATTERY CHARGERS?
Yes: providing a stable input voltage improves the efficiency and useful life of auxiliary systems and reduces battery transfer events.
