Bluewave

Definition
Harmonic oscillations (HO) are an integral multiple of the base frequency of a non-sine, periodic oscillation. They are identified with the ordinal number n = 2, 3, 4 ... Example: In a 50-Hz network, the 5th HO is equal to 250 Hz or the 7th HO to 350 Hz. They are generated in the consumer and then spread from there into the mains supply.

Cause
Harmonic oscillations arise in non-linear consumers such as:

• Switching power supplies
• Variable-speed motors
• Fluorescent tubes with fluorescent lamp ballasts
• Arc furnaces
• UPS systems
• Frequency converters
• Thyristors to control halogen lamps

Consequences
Harmonic oscillations result in additional currents that the circuit has not been designed to deal with. This not only causes problems in the mains supply, but also in electrical systems. As a result, relays, residual current protective devices, and fuses may malfunction. Electrical devices may also overheat and suffer increased wear as a result.

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Definition
Reactive power is required to generate electrical and electromagnetic fields, but cannot be used to convert energy in the consumer.

Cause
Reactive power occurs when an alternating or three-phase current power supply does not exclusively contain ohmic consumers. Examples:

• Fluorescent lamp ballasts
• Transformers
• Asynchronous motors

Consequences
Larger conductor cross-sections are needed in the supply lines, as well as larger generators and transformers, since the reactive power oscillates between the generating system and consumers. The current oscillating back and forth also results in ohmic losses in the lines. Large, industrial electric consumers must thus also pay for their "reactive power consumption" in addition to the active power used.

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Definition
A flicker is a "flare" in illumination caused by voltage fluctuations. A differentiation is made between short (short-time flicker) and periodic disturbances (long-time flicker).

Cause
A flicker is caused by voltage fluctations and voltage dips, which can be caused by:

• Welding machines
• Arc furnaces
• Startup and load changes of powerful electrical motors
• Pulsed power (burst firing control)

Consequences
Flickers interfere with illumination: The luminance fluctuates and the spectral distribution of the light changes. This endangers operational safety and strong flickers can even damage the health of employees. Furthermore, illuminants may age prematurely due to the voltage fluctuations.

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