Linear Grounding against Total Harmonic Distortion (THD) Based on Faden Spectrum Phenomenon

Abstract

Hazar Shtat and Nazih Haidar

This applied research deals with the effect of capacitive harmonics on the efficiency of electrical and electronic devices used in installing a giant screen owned by Faden Spectrum Company, which was installed on one of the huge towers in the city of Al-Khobar in the Kingdom of Saudi Arabia, with an area of 2000 square meters, and consisting of 2000 cabinets containing 2000 electrical cells.

The area of each cell is 1 m2 .

The problem was solved - significantly - by linear grounding, which also provided creative solutions for four similar screens of relatively smaller size, which may allow this type of grounding to be generalized to all electrical networks with similar problems.

Under our supervision, the engineering team worked to reduce the annoying noise coming from the main feed box (MDB), which was increasing steadily with increasing lighting intensity, to become 90 dB at 60% brightness and 155 dB at 100% brightness, by building independent linear grounding.

It deals with the zero-point grounding of the transformer, and this applies to the screen feeding system as a whole, provided that the old grounding remains as a grounding against touch currents to protect individuals from electrification.

Our engineers successfully reduced harmonic noise from 95 dB to 55 dB at 50% brightness (the normal operating rate for this type of display at noon).

The apparent current on neutral has also been reduced to 438A instead of 811A at the same brightness rating.

This solution also reduces the size of the active harmonic filter to less than half, saving a lot of money when the customer wants to reach typical values with a THD filter.

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