Zero-Sequence Harmonic Filter ZSF

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Since computer loads and single-phase nonlinear loads like electronic fluorescent light were spread, zero-sequence harmonic current of neutral wires has caused severe errors of electric equipment, such as distribution line overheating and malfunction of circuit breakers and relays.
The Zero Sequence Harmonic Filter (ZSF) is a semi-permanent filter designed and manufactured to minimize zero-sequence impedance. Therefore, it can keep performance in any positions from the secondary terminal of transformer to the panel board at the end of load, and has an easy-to-install structure.
The filter is capable of removing over 90% zero-sequence harmonic current depending on an installation position in order to stabilize the power quality of systems. It is widely applied to three-phase four-wire distribution systems.
Problems of zero-
sequence harmonic
    • Circuit breaker trip by overcurrent
    • Temperature rise and thermal degradation of transformer
    • Malfunction of protective equipment
    • Neutral conductor overheating and fire occurrence
    • Communication problem
고조파 적용
Application loads Computer, OA device, electronic stabilizer, medical device, broadcasting system, single-phase SCR heater, single-phase UPS
Application systems Three-phase four-wire distribution system
Application places Information processing center, factory, hospital, building, office, oficetel, school, apartment, computer academy
Problems of zero-
sequence harmonic
Step1. Find an appropriate place for installation
  • Find a good place to install ZSF.
  • The closer the ZSF is to a load, the more the reduction rate can be generated.
Step2. Measure the maximum current of neutral
  • To select a ZSF rate, it is very important to measure the maximum current.
  • If a product is selected with no measurement of current, it is necessary to set the maximum current of neutral to a value three times higher than single-phase current.
Step3. Select in the table of standard rating
  • Based on the maximum current value of neutral, select a ZSF in the stable of standard rating.

Product Features

  • Acquired patents
    • Patent no. 0435106, The harmonic reduction apparatus which use the resonance of the zero-phase-sequence impedance (expired)
    • Patent no. 0493987, Advanced Zero Sequence Harmonic Filter (expired)
    Reduction in line current

    Removal of plenty of zero-sequence harmonic current over line and reduction in line current in case of single-phase nonlinear load use

    Reduction in neutral current

    Removal of up to 90% zero-sequence harmonic current over neutral

    Satisfied specification of harmonic limits
    • The voltage/current distortion factors caused by zero-sequence harmonic, lower than standard harmonic limits
    • Satisfied specification according to the harmonic limits of KEPCO, IEEE-519, AS-2279, and BS G5/4
    Solved power quality problems
    • Prevention of transformer damage and capacity reduction by vortex of zero-sequence harmonic current
    • Prevention of line & neutral cable heating and damage
    • Reduction in current unbalance factor
    • Power rate reduction through the improvement in power factor of system
    • Prevention of abnormal trip in order for the stable operation of system
    Easy product installation

    Standardization and specification for installation in line with the maximum current over neutral regardless of field survey and system simulation

    Easy product selection

    Product selection in line with the maximum current over neutral depending on the 30A to 3000A installation position

    Simple maintenance
    • Product standardization for easy maintenance
    • Over 10 years of excellent durability

Product Principles

Installation Effects

  • Control of transformer & cable temperature rise and prevention of fire by zero-sequence harmonic
  • Three-phase balance and system stability secured through the solution of neutral overcurrent & overvoltage problems
  • Increases in distribution system capacity and reliability; prevention of abnormal trip of MCCB
  • Extension of the lifespan of electric device through the control of transformer & electric device overcurrent
  • Power rate reduction through the improvement in power factor of power system
  • Reduction in K-Factor generated by harmonic current of nonlinear load

Product Specification

게시판 리스트
Type name Load capacity Enclosure dimension [mm] Weight [kg]
Phase Neutral HP D H
ZSF22050 16.7 50 350 500 500 70
ZSF22100 33 100 420 730 800 150
ZSF22150 50 150 420 730 800 180
ZSF22200 67 200 420 730 800 200
ZSF22250 83 250 420 730 800 250
ZSF22300 100 300 600 1000 1000 350
ZSF22400 134 400 600 1000 1200 400
ZSF221000 333 1000 800 1500 1800 550
ZSF221500 500 1500 800 1500 1800 650
ZSF223000 1000 3000 1100 1500 1800 900

※ A product size can be different depending on an installation location or condition. Therefore, please make sure to check it before placing an order.