HF
Single-tuned harmonic filter
A shunt series-LC branch tuned near one harmonic order to sink that harmonic current from the network.
SLD / Schematic
Symbols · HPF
Damped high-pass harmonic filter
A shunt filter with a resistor across its reactor, giving low impedance over a broad band of higher harmonics.
In plain English
What does Damped high-pass harmonic filter mean?
A damped high-pass filter adds a resistor in parallel with the reactor of a capacitor-reactor branch. Above its corner frequency the filter impedance stays low across a wide band, so it absorbs higher-order harmonics and damps resonances rather than sinking one specific order. The C-type variant adds a second capacitor to remove fundamental-frequency losses in the resistor.
A simple example
Drawings show the capacitor in series with a reactor that has a resistor in parallel, sometimes with the extra capacitor of the C-type arrangement in series with the reactor. It is used beside tuned filters in static var compensators, large rectifier plants and some converter connection points.
What the drawings help you do
The resistor dissipates real power, so its thermal rating is as important as the electrical values. The symbol does not show the corner frequency or the loss figure, which come from the filter design report.
This particular reference
A shunt filter with a resistor across its reactor, giving low impedance over a broad band of higher harmonics. A damped high-pass filter covers a band of harmonics; a single-tuned filter sinks one order and has no resistor branch.
- Terminal
- An identified point where a conductor connects.
- Rating
- A value stating the conditions for which equipment is specified.
- Schematic
- A drawing showing function and connections rather than physical appearance.
Read the source: Capacitor and filter product offerings · Resistors and heater-element symbols
SLD / Schematic · HPF
What it represents
A damped high-pass filter adds a resistor in parallel with the reactor of a capacitor-reactor branch. Above its corner frequency the filter impedance stays low across a wide band, so it absorbs higher-order harmonics and damps resonances rather than sinking one specific order. The C-type variant adds a second capacitor to remove fundamental-frequency losses in the resistor.
Drawings show the capacitor in series with a reactor that has a resistor in parallel, sometimes with the extra capacitor of the C-type arrangement in series with the reactor. It is used beside tuned filters in static var compensators, large rectifier plants and some converter connection points.
The resistor dissipates real power, so its thermal rating is as important as the electrical values. The symbol does not show the corner frequency or the loss figure, which come from the filter design report.
How to read it
- A resistor across the reactor marks a damped filter.
- An extra series capacitor indicates a C-type arrangement.
Information to show or reference
- State corner frequency, Mvar and resistor rating.
- Show resistor and capacitor arrangement.
- Reference filter design report.
A distinction that matters
A damped high-pass filter covers a band of harmonics; a single-tuned filter sinks one order and has no resistor branch.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
Capacitor and filter product offerings
Public passive and harmonic filter product context.
Resistors and heater-element symbols
Public resistor symbol family context.
About this graphic
This illustration was authored independently by Elora Grid to explain the concept. It is not reproduced from a customer drawing, an official standard graphic or a manufacturer CAD file. Its correspondence to an exact IEC or IEEE symbol identifier has not been certified.
SVG and DXF downloads contain this original artwork. DXF uses unscaled drawing units; a GA envelope supplies no product dimensions, clearances or fabrication information. Original artwork is available under CC BY 4.0. Third-party references retain their own terms.
Explore related references
SVC
Static var compensator
A shunt reactive power compensator built from thyristor-controlled reactors, thyristor-switched capacitors and filters.
SLD
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Resistor
A resistive component with its value and purpose documented separately.
Schematic
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Reactor
A reactor is an inductive component used for a documented power-circuit purpose.
SLD / Schematic
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