Q1: Harmonics can lead to serious problems
- A: Harmonics can lead to serious problems • Reduced energy efficiency when harmonics are in the network • Overheating of cables, motors and transformers • Damage to sensitive equipment • Tripping of circuit breakers • Blowing of fuses • Premature ageing of the installation • Capacitor overloading and failures • High current in neutral conductors • Excitation of network resonance • No connection permit from the utility if harmonic levels are too high
Q1: Total Harmonic Distortion, THD
- A: The square root of the sum of squares of all individual har- monic distortions (voltages or currents) is called the Total Harmonic Distortion (THD).
Q1: Distortion factor
- A: The ratio of the rms value of the harmonic content to the rms value of the fundamental quantity, expressed as a percentage of the fundamental frequency. (IEV 131-03-04 modified) DF = (sum of the squares of rms values of the harmonics)1/2 / rms value of the fundamental frequency x 100%
Q1: Displacement factor
- A: The ratio of the active power of the fundamental wave to the apparent power of the fundamental wave. (IEV 131-03-21 modified)
Q1: Double-tuned filter
- A: Filter configuration with two tuning frequencies, mainly used in HVDC filter systems.
Q1: C-type filter
- A: High-pass filter modified with an extra capacitor to short- circuit the resistor for the fundamental frequency. Alternative when a damped filter is needed for a low-tuned filter (normally n < 5).
Q1: High-pass filter
- A: A damped band-pass filter. A resistor is connected in parallel with the reactor in a band-pass filter, which creates damping on the parallel resonance.
Q1: Band-pass filter
- A: A reactor (inductance) connected in series with a capacitor (capacitance).
Q1: Damped filter
- A: A filter with low, predominantly resistive, impedance over a wide band of frequencies. (IEC 61642)
Q1: Detuned filter
- A: A filter with a tuning frequency more than 10% below the lowest harmonic frequency with considerable current/voltage amplitude. (IEC 61642)
Q1: Tuned filter
- A: A filter with a tuning frequency that differs by no more than 10% from the frequency that is to be filtered. (IEC 61642)
Q1: Rated output
- A: Rated output is the theoretical power of the bank/system generated at the rated voltage, expressed in Mvar. It is also referred as installed power.
