Harmonic Filters – Optimized Power for Saudi

Harmonic Filters

• A “linear” load connected to an electrical power system is defined as a load which draws current from supply which is proportional to the applied voltage. For example: resistive load, incandescent load.
• A load is considered to be “non-linear” if the impedance changes with the load. Due to this change in impedance the current drawn by non linear load is also non sinusoidal in nature, even when it is connected to sinusoidal voltage source. For example: computers, variable frequency drives, discharge lighting.
• These non sinusoidal currents contain harmonics current which interacts with the impedance of power distribution system to create voltage distortion that effects both distribution system equipment and the load connected to it.
• Static power converters are the equipment which use semiconductors to convert AC to DC, DC to AC and AC to AC and constitute the largest non linear load connected to electrical power system.
• These converters are used in various purpose in industry such as uninterrupted power supply, variable frequency drives, SMPS etc. These converters used in variety of application draw non linear current and distort the supply voltage waveform.
• These non sinusoidal components are divided into two components: fundamental component and harmonics component.
• The higher the harmonics portion of the quantity the distortion of this quantity, or in other words the larger the deviation of the quantity from sinusoidal fundamental frequency.