Voltage Dip
Voltage Dip: Temporary Voltage Drop in Generators
Definition
“A temporary dip in generator voltage when a load is attached, before the AVR system corrects it.”
A voltage dip occurs when a generator experiences a momentary drop in voltage due to a sudden increase in electrical load. This is a common phenomenon in power generation, particularly when large motors, compressors, or high-starting-current equipment are connected.
Causes of Voltage Dips in Generators
- High Inrush Current from Large Loads – Motors and heavy equipment draw a high starting current, causing an initial voltage drop.
- Generator Undersizing – A generator with insufficient capacity struggles to maintain voltage under load.
- Slow Response from the Automatic Voltage Regulator (AVR) – The AVR system adjusts voltage, but there is a brief delay before stabilization.
- Weak Fuel or Mechanical System – Fuel delivery issues or engine speed fluctuations can impact voltage stability.
Effects of Voltage Dips
| Effect | Impact on Equipment |
|---|---|
| Flickering Lights | Noticeable dimming when large loads switch on. |
| Unstable Performance | Sensitive electronics may malfunction. |
| Generator Strain | Repeated dips may cause overheating and efficiency loss. |
How to Minimise Voltage Dips
- Use an Appropriately Sized Generator – Ensure the generator has enough capacity for peak loads.
- Install a High-Quality AVR System – A faster, more responsive AVR helps stabilise voltage quickly.
- Use Soft Starters or VFDs (Variable Frequency Drives) – Reduces inrush current from large motors.
- Manage Load Application – Stagger load connections to avoid a sudden surge in demand.
Conclusion
Voltage dips are temporary but impactful, affecting generator performance and electrical stability. Proper generator sizing, AVR calibration, and load management can help minimise voltage dips and ensure smooth power delivery.
