DC Filter and Characteristics - AC and DC filters - High Voltage Direct Current Transmission

TL;DR

DC filters are used in HVDC transmission systems to eliminate characteristic and non-characteristic harmonics in DC voltages, which cause current harmonics and noise in telephonic lines.

Transcript

hello everyone welcome to ekeeda platform and this is dawn giant here your electrical faculty and in this video i'm going to talk about the dc filters and its characteristics so so i will start with the dc filter concepts what are actually it is important and what we are actually needed in the dc filter so already we were using the ac filters which... Read More

Key Insights

• 🫥 DC voltages in HVDC transmission systems contain both characteristic and non-characteristic harmonics, which can cause current harmonics and noise in telephonic lines.
• ⚡ The effectiveness of DC filters is determined by the maximum TIF value on the DC side voltage bus and the maximum included noise voltage in the parallel test line.
• ✋ Single tuned and double tuned filters are used to filter out lower order harmonics, while high pass filters are used for higher order harmonics.
• 🍻 DC filters help in limiting the magnitude of overvoltages and elongating the front time in monopolar links.
• ⚡ The permissible value for induced noise voltage in monopolar operation is 18 to 20 millivolt per kilometer.
• ✊ DC filters are designed solely to eliminate DC harmonics and do not supply reactive power like AC filters.

Questions & Answers

Q: What are characteristic and non-characteristic harmonics in DC voltages?

Characteristic harmonics in DC voltages follow the relation np +/- 1, while non-characteristic harmonics do not follow this pattern. These harmonics cause current harmonics and noise in telephonic lines.

Q: How does the harmonic current vary along the line in HVDC transmission systems?

The harmonic current varies from point to point along the line, depending on the distance from the converter stations. This can result in oscillations and variations in the harmonic current.

Q: How is the effectiveness of DC filters judged?

The effectiveness of DC filters is judged by the maximum TIF value on the DC side voltage bus and the maximum included noise voltage in the parallel test line situated one kilometer away from the HVDC lines.

Q: How are harmonics filtered out in HVDC systems?

Sixth and twelfth harmonic voltages can be filtered out using single tuned and double tuned filters. Higher order harmonics are filtered out using high pass filters.

Summary & Key Takeaways

• DC voltages in HVDC transmission systems contain characteristic and non-characteristic harmonics, which cause current harmonics and noise in telephonic lines.

• The effectiveness of DC filters is judged by the maximum TIF value on the DC side voltage bus and the maximum included noise voltage in the parallel test line situated one kilometer away from the HVDC.

• Single tuned and double tuned filters are used to filter out sixth and twelfth harmonic voltages, while high pass filters are used to filter out higher order harmonics.