A Harmonic Filter resistor (or damping resistor) reduces harmonic distortions in industrial power systems. These resistors are often combined with inductors and capacitors as a harmonic frequency filter.

We manufacture elements and enclosures to best meet your system’s power rating, inductance limits, and voltage requirements. Our filter resistors can have different protection ratings, including IP20, IP23, IP56 NEMA 1, NEMA 3R, NEMA 4 and NEMA 4X in galvanized steel, hot-dip galvanized steel, stainless steel and anodized aluminum enclosures. Additionally, our assembly offers options like post insulators and elevating stands, among many other options.

The Importance of Eliminating Harmonic Distortions

Harmonic distortions, caused by non-linear loads and varying power demands, can lead to various issues, including energy losses, overheating equipment, and premature aging of electrical components. These distortions can also cause malfunctions in sensitive electronic devices, disrupt communication signals, and lead to costly downtime. As a result, eliminating harmonic distortions maintains the efficiency and reliability of modern electrical systems.

By addressing harmonic distortions, businesses can ensure a stable and efficient power supply, reduce operational costs, and extend the lifespan of their electrical infrastructure.

Purpose

In a normal AC power system, supply voltage varies sinusoidally with a fundamental frequency of 50 or 60 hertz (Hz). When linear loads are connected to the system, sinusoidal currents will be drawn from the system at the same frequency as the voltage.

However, when non-linear loads are connected, a series of sinusoidal currents (harmonics) will be drawn at integer multiples of the fundamental frequency, resulting in distortion of the fundamental signal. Harmonic filters are employed to mitigate, reduce and eliminate problems such as increased energy wastage, insulation failure and permanent damage to equipment.

Harmonic filters generally consist of capacitors and inductors tuned to resonate at a single frequency or through a band of frequencies. Adding a resistor to the filter allows greater tolerance of temperature changes in the components by damping the unwanted frequencies. It smoothens the filter’s response at the tuning frequency and widens the passband to cover a wider range of harmonics.

Certifications and Standards

Electrical Code	Harmonic Filter Resistor	Switchgear and Control Equipment	Mechanical Structure
CSA 22.1 NFPA 70	CIGRE 14-30 IEEE 1531	UL 508 C22.2 No. 14-05	C22.2 No. 94.1 UL50 NEMA ICS 6 NEMA 250 ANSI/IEC 60529 ANSI 2535.4

Ratings and Options

Basic Insulation Level	Up to 1050 kV
Resistance	We can supply any required resistance value
Power	Up to 2MW
Application	Indoor/Outdoor
Ambient Temperature	-40° to + 60°C
Protection Degree	NEMA 1 to NEMA 4X (IP20 – IP56)
Standards	IEEE, ISO, IEC, NEMA, CSA
Special Requirements	Different transient power
Environmental Considerations	Wind speed, Altitude, Seismic, Pollution

Enclosures

Applications	Indoor/Outdoor
Enclosure Finish	ANSI/ASA 61 Grey (Custom Enclosure finish is also available)
Enclosure Materials	Galzanized Steel, Stainless Steel (304,316), Aluminum
Protection Degree	NEMA 1, NEMA 3R, NEMA 4, NEMA 4X IP 20, IP 23, IP56

Applications

Our resistors are generally made for MV to HV voltage levels and can be used in:

HVDC conversion stations (LCC & SVC)
FACT Stations which may be used for:
Transmission voltage regulation
Power quality and transfer increase
Reactive power control
Reactive power control for MV motors (Mining)
Voltage stabilization (Wind farm)
Arc furnaces, rolling mills (Metal)

Elements

Our resistive elements have been designed specifically to meet the requirements of Harmonic Filters. We use specialized corrosion-resistant alloys with a low coefficient of change in resistance with temperature. Our resistive elements are flat to reduce inductance to a minimum and are arranged in banks insulated to 11 kV to reduce the space required for the typical industry requirements.

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905 602 8952

Note: Dimensions are without external Insulators
Enclosure Type	HF-1	HF-2	HF-3
A	69”	69”	69”
B	77”	77”	101”
C	50”	85”	85”
Max Power	50kW	100kW	200kW

Harmonic Filter Resistors Servicing Toronto and All of Canada