HSD HarmonicShield 5% Passive Harmonic Filter

Industry leading performance with
remote connectivity and intelligent control.

Nonlinear loads, such as Variable Frequency Drives and UPS systems, reduce energy costs and provide system efficiencies. However, they also create harmonic distortion, also known as current distortion or line distortion. When present in the voltage and current of an electric power system, harmonics are considered undesirable distortion which can adversely affect power system infrastructure and loads.

The HSD HarmonicShield with PQconnect offers industry leading 5% THID Total Harmonic Current Distortion (THID) performance even at light loads and under the harshest of environments. The optional contactor allows the tuning circuit to be disconnected at light loads to avoid leading power factor problems. Natural convection cooling means no moving parts. The HSD with PQconnect offers the performance needed to meet the most stringent requirements of IEEE-519-2022. The HSD with PQconnect is equipped with ModbusRTU communications and intelligent contactor control to ensure seamless harmonic mitigation or Power Factor control. A lug kit option accommodates oversized cabling if needed. All of this is backed up by TCI’s 3-year warranty, which means you will have many years of hassle-free operation.

Benefits of Using a HarmonicShield Filter

  • Cost effective, simplified design
  • Limits current harmonic distortion to less than 5% over a wide load range
  • Industry leading performance
  • Intelligent control and monitoring available with PQconnect
  • IEEE 519-2022 compliant
  • Increases drive uptime
  • Eliminates nuisance tripping of circuit breakers

Quality Components

  • Rugged Line and Tuning Reactor
  • Harmonic Grade Power Capacitors
  • Optional Tuning Circuit Contactor
  • Optional Lugs
  • UL Type 1 or Type 3R Transformer Style Enclosure
  • RoHS / RoHS II Compliant
  • Made in the USA

PQvision Software Applications

A free desktop application and mobile app created by TCI for PQconnect data

PQvision software gives you visibility into:

  • Real-time filter line/load voltage and current metering values
  • Real-time THID, and THVD
  • Voltage and current Wave forms
  • Harmonic Spectrum
  • Filter status detections
  • Bluetooth connectivity via Android & IOS app

Use the links below to download the PQvision software in the desktop version or mobile app version.

Introducing EtherNet/IP the Future of Connectivity

TCI’s HGP Passive Harmonic Filter now includes EtherNet/IP connectivity. It is now easier than ever to connect, control, and manage your Harmonic Filter within an EtherNet/IP driven network.

Seamless Integration:No need for additional costs using an EtherNet/IP gateway.  PQconnect communications now allow for ultimate compatibility with your EtherNet/IP dependent PLC or HMI device.

High Speed Performance: Experience lightning-fast data transfer and real-time communication of your Harmonic Filter with implicit messaging. With near zero information latency, Filter status and Power Quality characteristics are always at your fingertips.

Decrease Setup Time: Leverage our Licensed AOP EDS file for an easier setup with Rockwell or EtherNet/IP dependent devices. Individual Controller Tags for all PQconnect Implicit IO data will always auto populate.

Unfiltered Waveform without the HarmonicShield
Harmonics can cause a number of issues, including transformer and distribution equipment overheating, random breaker tripping, sensitive equipment failure, and poor power factor.
Resulting Line Current Waveform
with HSD
The HarmonicShield not only limits current distortion to less than 5% TDD, it also improves true power factor.
Previous slide
Next slide

Generator Compatibility + Intelligence

Serial Communication

The HSD with PQconnect is an intelligent passive harmonic filter with generator compatibility. The filter can autonomously control its tuning circuit contactor based on your input system to ensure worry-free operations for generator-based systems.

With PQconnect, the HSD provides data monitoring and status updates on the filter directly to you SCADA system through Modbus RTU. The filter will communicate informational alerts to ensure your system stays running and resolves power quality issues.

Industrial Strength

Filter Status Detections

Our products are built in the USA, using high quality components. This allows our passive filters to deliver best in class performance under the harshest conditions and in the most challenging applications.

Receive alerts before problems occur. With PQconnect, users will be notified if issues were to arise, including on the components of your filter. This will prevent unnecessary downtime and will alert the user when capacitors are nearing end of life.


SCCR Marking

Note: The HarmonicShield filter is UL Listed as an Auxiliary Device in accordance with PART X of UL 508 Standard for Industrial Control Equipment and does not require a SCCR or marking. HSD is not an Industrial Control Panel and so does not require a Short Circuit Current Rating such as is required of Industrial Control Panels to be in compliance with NFPA NEC Article 409. For applications requiring a SCCR, TCI offers the HGP product which features the same performance as the HSD and is an Industrial Control Panel with a true SCCR rating of 100ka.


  • PQconnect, Contactor and lug kit.

Offering lugs as kits allows us to keep the standard product costs to a minimum, especially on the larger units.

  • Yes. UL 508 requires either lugs or for lugs kits to be available to install in the field. Both options are available.

For some faults, the tuned circuit contractor can be configured to open on a fault condition, specifically for tuned circuit line reactor overloads.

In other circumstances, the fault detection is informational only such as the line reactor overload. In the case of a line reactor overload opening the tuned circuit contactor can make the overload worse as it forces harmonics flowing into the tuned circuit to instead flow through the line reactor.

  • Voltage: 120VAC
  • Current: 0.6A steady state, 20A inrush.