Sag : A sag in an electrical power supply refers to a temporary reduction in voltage levels, typically below 90% of the nominal voltage, lasting from a few milliseconds to several seconds. Sags can be caused by various factors, including:
1. Faults in the power grid or distribution system
2. Starting of large motors or loads
3. Lightning strikes
4. Short circuits
5. Overloading of the system
Effects of sags on electrical equipment:
1. Malfunction or failure of sensitive electronics
2. Data loss or corruption
3. Process interruptions
4. Reduced productivity
5. Increased maintenance costs
Types of sags:
1. Shallow sag: 90-95% of nominal voltage
2. Deep sag: 80-90% of nominal voltage
3. Very deep sag: below 80% of nominal voltage
Mitigation strategies:
1. Voltage regulators
2. Uninterruptible power supplies (UPS)
3. Sag correctors
4. Power conditioners
5. Redundant systems
Swell : A swell in an electrical power supply refers to a temporary increase in voltage levels, typically above 110% of the nominal voltage, lasting from a few milliseconds to several seconds. Swells can be caused by various factors, including:
1. Faults in the power grid or distribution system
2. Switching of power factor correction capacitors
3. Lightning strikes
4. Grid voltage fluctuations
5. Uninterruptible power supply (UPS) failures
Swell effects on electrical equipment:
1. Damage to sensitive electronics
2. Overheating of motors and transformers
3. Failure of power supplies and UPS systems
4. Data loss or corruption
5. Equipment malfunction or shutdown
To mitigate the effects of swells, various solutions can be implemented, such as:
1. Voltage regulators
2. Surge protectors
3. Over voltage protection devices
4. Power conditioners
5. Redundant systems
Regular monitoring and analysis of the electrical system can help identify potential swell issues and guide the implementation of effective mitigation strategies. Sub cycle A sub cycle in an electrical supply refers to a voltage or current disturbance that lasts for less than one complete cycle (typically 16.67 milliseconds for a 60 Hz system). Su bcycles can be caused by various factors, including:
1. Switching of power electronic devices
2. Lightning strikes
3. Grid voltage fluctuations
4. Faults in the power grid or distribution system
5. Electromagnetic interference (EMI)
Types of sub cycle disturbances:
1. Voltage dips
2. Voltage spikes
3. Current surges
4. Harmonic distortion
5. Inter harmonics
Effects of sub cycles on electrical equipment:
1. Malfunction or failure of sensitive electronics
2. Data loss or corruption
3. Process interruptions
4. Reduced productivity
5. Increased maintenance costs
Mitigation strategies:
1. Power conditioning equipment (e.g., active filters, passive filters)
2. Surge protectors
3. Voltage regulators
4. Uninterruptible power supplies (UPS)
5. Electromagnetic compatibility (EMC) filters. A Transient: transient in a power supply refers to a short-duration voltage or current disturbance that can cause equipment malfunction or failure. Transients can be classified into two types:
1. *Over voltage transients*: Voltage spikes or surges that exceed the normal operating voltage.
2. *Under voltage transients*: Voltage sags or dips that fall below the normal operating voltage.
Causes of transients:
1. Lightning strikes
2. Switching of power electronic devices
3. Grid voltage fluctuations
4. Faults in the power grid or distribution system
5. Electromagnetic interference (EMI)
Effects of transients:
1. Equipment damage or failure
2. Data loss or corruption
3. Process interruptions
4. Reduced productivity
5. Increased maintenance costs
Mitigation strategies:
1. Surge protectors
2. Voltage regulators
3. Uninterruptible power supplies (UPS)
4. Power conditioning equipment (e.g., active filters, passive filters)
5. Electromagnetic compatibility (EMC) filters. Phase angle in a power supply refers to the difference in timing between the voltage and current waveforms. In an ideal power supply, the voltage and current waveforms are in phase, meaning they reach their peak values at the same time. However, in reality, there can be a phase shift between the two waveforms, resulting in a phase angle.
Types of phase angles:
1. _Leading phase angle_: Current leads the voltage waveform.
2. _Lagging phase angle_: Current lags the voltage waveform.
Causes of phase angles:
1. Inductive loads (e.g., motors, transformers)
2. Capacitive loads (e.g., filters, capacitors)
3. Power factor correction (PFC) circuits
4. Harmonic distortion
Effects of phase angles:
1. Reduced power factor
2. Increased reactive power
3. Overheating of equipment
4. Reduced efficiency.