De-tuned Capacitor Bank – Economical Way to Mitigate Harmonics

TANGEDCO – Distribution Utility for Tamil Nadu State has given a regulation regarding Harmonic Mitigation, under direction of tariff order by Tamil Nadu Electricity Regulatory Commission (TNERC), wherein any HT consumer/generator need to meet the specified Harmonic limits as per norms stipulated in CEA regulation on grid code.
TANGEDCO measures the level of Harmonics and issues a notice if the value exceeds the CEA specified limit and if the consumer is unable to mitigate Harmonics within the specified limit after notified period, penalty is imposed every month.

Due to above tariff penalty mechanism the HT consumers started looking at mitigation techniques wherever the harmonic distortion is reportedly high. Most of these facilities already had reactive power compensation in terms of capacitor banks installed. These capacitor banks too suffered from failure etclike other electrical equipment failure due to high harmonic distortion levels.
In some cases based on harmonic spectrum, installed capacitor banks can be used to mitigate harmonics. After detailed and proper analysis of harmonics in the system mitigation techniques like tuned harmonic filters or capacitor with reactor can also used as harmonic filteration technique.

This case study explores such possibility that can be beneficial for industry to look at available resources for addressing harmonic mitigation and optimize their expenses in deploying fresh investment to avoid harmonic penalty.

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