Capacitors for reactive power compensation Zvar
In beginning of year 2015 Zenex company will introduce to market our own Zvar power capacitors. They are made from single-phase modules, with its individual overpressure and overcurrent protection. These capacitors thanks to innovative solutions completely comply with requested standards, and keep them ahead of the competition.
|Characteristics elements||Zvar® modular capacitor|
|Enclosure||Non-flamable and auto-extinguishing Poliamide in V0 flamability class|
|Need to be grounded||No - double insulation - class 2|
|Dielectric / Winding||Polipropylen film, Alu-zinc metallized|
|Impregnant||Totally dry, cast resin technology|
|By operation of an overpressure device inside the enclosure|
(flexible membrane, that disconnects normalized fuse link))
|Capacitor and enviroment|
|No risk because:|
|Ambient temperature class||-40 do +55°C|
|Permitted casing temperature||90°C|
|Average temperature on 24h||45°C|
|Watt losses (in heat)||<0,3W / kvar (internal resistor included)|
|Maximum admissible voltage|
- according to standard IEC 60831-1 i 2
|Ucn + 20% 24h/24h|
Ucn + 25% 18h/24h
Ucn + 30% 12h/24h
Example Ucn = 440V + 20% = 528V 24h/24h - Permanent
|Maximum admissible current||1.5 ln|
|Tested with voltage|
(terminal to terminal)
|2,15 Un AC 10sec.|
|TTested with voltage|
(terminal to enclosure)
|6kV AC 1min|
15kV AC 1,2/50μ sec.
|Statistical life expectancy||>130 000h|
|Mounting position||Any position, because dry resin impregnant|
Zar® capacitors are designed, and made in dry cast resin technology. Elementary unit is single-phase winding module, that provides
high flexibility in configuration complete set. Modules connected in delta, or star configuration gives three-phase unit at different
electrical parameters, according to power, and nominal voltage.
Modules connected in parallel, or serial gives possibility to build single-phase capacitor in high power, or high nominal voltage.
Windings are created from two polypropylene films with alu-zinc coating on one site, metal coating forms electrode, and polypropylene film forms insulation. Winding is coated by self-extinguishing thermosetting polyurethane resin which forms the casing, providing mechanical and electrical protection.
Winding external casing is made of polyamide >PA66-GF25<, that has V0 flammability resistance, according to standard ISO 1210/UL 94.
No impregnation, insulation liquid, or gas is used in Zvar® capacitors, this unit complies fully with environmental protection requirements (PCB-free).
Nowadays all low voltage power capacitors are produced on self-healing metalized polypropylene windings: this property
results from enough thin metallization, that in case of overvoltages, when it perforate the dielectric and cause
discharges, which vaporize the metallization near short circuit, thus instantaneously restoring the electrical insulation.
However, if the damage is bigger, and will not be self-healed, or capacitor is highly overloaded for a longer time, then internal fuse will melt, or internal gases will rise up pressure, and overpressure device will disconnect the capacitor. Hitherto all capacitors activation of protection makes capacitor end of life.
Zvar capacitor is the one and only with unique protection system. required by EN_60831-1 norm, that can undergo to „Factory regeneration” after protection activation:
Activation of any protection that are installed do not cause external enclosure dimension, or shape change:
- It has normalized 14x51mm fuse link that gives reliability to work and protect at respectively enough high current level;
- It has internal overpressure device that disconnect fuse link instantly when internal high pressure will appear;
- It’s probably the only one capacitor with resin filling that have chamber under overpressure device to collect gases;
- Overpressure membrane react on high pressure in the chamber, when at opposite site it have atmospheric air - that assures reliable operation, and very good heat dissipation;
- In case of many electrical anomalies at working capacitor our protection mechanism is the only one in the world that do not damages irreversibly the capacitor protection.
- Except normalized fuse link, that can be replaced for new one, there is no mechanical, or electrical part, that could be damaged during protection activation;
- Each single-phase module has it own individual protection, that’s why if in one of them protection will activate, and disconnect the phase, other modules, that are fine, can be used to build three-phase capacitor with one new module;
Internal protections - description of operation
Protection of single-phase Zvar® capacitor module contains internal overpressure device, that is membrane
made of flexible Polypropylene. Under the membrane there is chamber, in which can be collected gas from vaporized
metalized capacitor winding. After achieving assumed critical internal pressure under flexible membrane. Membrane is
rapidly switching to push bolt, that was pushing fuse holder. This holder is placed between two springs hard, and soft.
If the bolt is in original position, the hard spring is pushing fuse holder to fuse contacts. If the bolt is pushed out,
the hard spring is completely released, then soft spring is pushing out rapidly the fuse holder from fuse contacts,
causing disconnection the capacitor winding circuit.
Zvar® capacitor is the only one, that when after trip of any protection (overpressure, or overcurrent protection) it is having capacitor regeneration possibility. After internal tests it appeared that regeneration quantity and possibility depends from type of failure, that depends form conditions under which capacitor have worked. Regeneration process can be done only by the producer, after checking of protection device condition, and making type tests according to EN_60831-1 norm.
Placing mounting grips on top and on bottom part of the capacitor gives easy, and good conditions of capacitor montage and connection.
Designed system of terminals in form of copper busbars ended by 8mm metric hexagonal screws, with 39mm spacing gives stable and comfortable connection, even of most thick supply cables.
Zvar® capacitors are having double insulation class, thanks to it capacitor grounding is not needed.
Designed system in each single-phase module, of internal terminals, in form of square 6mm nuts gives fast and stable connections between single modules to build complete capacitor set with external terminal connections.
Capacitors are having few possibilities of terminals layout: 2-poles for single phase capacitor, 3-poles for star, or delta 3-phase capacitor, and 6-poles for 3-phase capacitor with open delta-loop connection, that gives possibility of any individual connection
Modular design (even in case of biggest power units) makes it easy for installation, and at the same time makes it in
smallest possible dimension.
Enclosure from plastic material is resistant to all solvents and atmospheric agents (rain, sun, salty air, etc.).
The Zvar® capacitor is perfect for installations in corrosive atmospheres. It can be used outdoor (on special request) with special terminals cover.
Made according to norm IEC/EN 60831-1 chapter 22
Resistor bullit-in capacitor modular enclosure ensure discharge to voltage less than 75V in time shorter than 3 minutes from network disconnection.
In case of discharge time less than 1 minute needed additional resistors 100kΩ/5W can be installed, or dedicated reactors ZenDISCHARGE, that ensure discharging time less than 5 seconds.
The Zvar® capacitors have loss factor less than (0,1÷0,3)×10-3 this value depends form capacitor total power, but this leads to a total wattage consumption of less than 0.3W/kvar including the discharge resistors.
Capacity tolerance in accordance with IEC60831-1 standard is ± 5% of rated capacity. The use of modern technology
allows to maintain a standard tolerance of ± 1%.
Effect of temperature on the change in capacitance is negligible.
It is assumed that in the range 20 to 50 °C the capacity remains constant. Technology ensures that, during the life of a Zvar® capacitor capacity decrease is negligible.
The Zvar® comply with folowing standards:
- European norm: EN 60831-1 & 2
- International norm: IEC 60831-1 & 2
The Zvar® capacitor characteristics summary
Double insulation class - no need of grounding, because no metallic enclosure elements.
Totally dry - no risk of impregnant leackage, or fire.
Any mounting position.
Enclosure - auto-extinguishing Polyamide in V0 class, reinforced by fibreglass. Durable compact design, resistant on corrosion, with possibility of outdoor installation.
Modular design - connections between internal elements of capacitors are flooded by resin (no risk of corrosion, overheating, or loose parts)
Winding that is covered by resin, gives reliability that air, or humidity will not have access to capacitor winding layer. This feature secure high quality and stability of parameters.
Internal electrical, and pressure protections for each single-phase module:
- self-healing metalized polypropylene film
- normalized fuse link, with minimum short circuit withstand I1=80kA
- overpressure membrane with rapid fuse link dissconnection mechanism
- unique possibility of broken capacitor module regeneration