Zero Sequence Filter

Model Number

ZSF

Applications

Applicable Loads Computer, OA equipments, Electronic fluorescent lamp, Single Phase SCR heater and UPS etc. Applicable System Single phase nonlinear loads on Three phase four wire system Applicable Locations Office/Commercial building, School, Shopping Mall, Department store, Apartment, Hospital, Factory etc.

Benefits

Reduce Line Current The ZSF can reduce rms value of line current by reducing zero sequence harmonic current that is produced by single phase non-linear loads in three phase four wire system. Reduce Neutral Current The zero sequence current in line make a large neutral harmonic current by trebling.
The ZSF can reduce this large neutral current up to 90% depend on ZSF location. Meet IEEE Std.519-1992 The ZSF enable most single phase non-linear loads to comply with both the voltage and current distortion limits of IEEE Std.519-1992 and other international limits such as AS-2279, EN61000-3-4, and BS G5/4.

Solve Power Quality Problems

• Protect loss and reduce capacity because of circulating effects by zero sequence harmonic current in transformer.
  
• Protect heating and loss of line and neutral cable that is effected by zero sequence harmonic current.
  
• Reduce unbalance of line current.
  
• Improve power factor.
  
• Reduce system loss.
  
• Reduce K-factor rating of load current at main transformer.

Economical and stand-alone solution The ZSF is standardized up to 3000A. Therefore, if maximum neutral current can be figure out,
the site survey and system simulation before installing are not necessary.

Features & Options

Compact and easy-to-install. Quite operation and proper ventilation. Neutral size for three times of line current. Standardized up to 3000A (based on neutral current). Ammeter displaying the neutral current in option. Neutral impedance adjuster upon request.

Principles

Duplicating Principle of zero sequence harmonic The zero sequence harmonic current produced by single phase non-linear loads can treble in neutral line and make problems.

Removing principle of zero sequence harmonic
Up to 90% maximum of zero sequence harmonic current flow into zero sequence transformer in the ZSF because zero sequence transformer is specially designed to have very low zero sequence impedance. This can effectively be moved zero sequence harmonic currents upstream from the ZSF.

Selection Tables
Select Zero sequence Filters based on the maximum neutral current at the location
that ZSF will be installed. 　

Catalog Number	Currents in neutral [A]	DIMENSIONS [mm]			WEIGHT [kg]	DRAWING
		W	D	H
ZSF22030	30	350	500	500	70	Fig A
ZSF22060	60	350	500	500	85	Fig A
ZSF22100	100	600	400	850	150	Fig A
ZSF22150	150	650	450	900	180	Fig A
ZSF22300	300	800	450	1000	350	Fig B
ZSF22450	450	800	500	1200	400	Fig B
ZSF22600	600	800	1500	2350	800	Fig B
ZSF221000	1000	1100	1500	2350	1500	Fig B
ZSF223000	3000	1100	1500	2350	3000	Fig B

Table 1. Selection table of the ZSF

• Current = Maximum neutral current
  
• W = Width, D = Depth, H = Height
  
• All weight and dimensions are subject to change without notice. 　 Recommended Ratings = Ip 3 (Ip = Phase currents in rms)

Step1. Find proper location Find proper location where the ZSF can be installed. Reduction ratio can be maximized if the ZSF is installed as close as possible to load side.
Step2. Measure max current at neutral line
Measuring max current at neutral line is very important to choose the rating of ZSF. If the rating of ZSF should be decided without measured current or design process, three times of max current at phase can be considered as max current at neutral line.
Step3. Choose the rating of ZSF at Table 1
Choose the proper rating of ZSF at Table 1 with max current at neutral line. 　

G. Case studies of the ZSF Case 1. Apartment
- Installed Product: ZSF22600 [600A] - Problem: an electricity failure by a large amount of neutral current produced by non-linear loads

Installing result: 75% reduction of neutral current

Case 2. Governmentt - Installed Product: ZSF2260 x 5 [60A] - Problem: an electricity failure by computer, OA equipment,
and other single-phase non-linear loads - Installing result: 84% reduction of neutral current

Installation Placee	Product	Neural Current		Reduction (%)
	ZSF 22060	422	7	83.3
1/2 Floor		98	23	76.5
3/4 Floor		67	17	74.6
5/6 Floor		57	14	75.4
7/8 Floor		46	12	73.9