CAPACITORS & CAPACITOR BANKS

POWER FACTOR CORRECTION CAPACITORS

 CAPACITOR BANKS,  CONTROLLERS AND COMPONENTS

The capacitors and capacitor banks are used in the energy sector (power factor correction), green energy generation (wind and photo voltaic power plants), traction systems and induction heating equipment.

Under normal operating conditions, electrical equipment (electric motors, transformers, welding machines, fluorescent lamps, etc.) consumes not only active power from the power system, but also reactive power. The active power is directly related to the output that converts the electric energy into other types of energy that produces useful work (i.e. mechanical energy, thermal energy, etc.). Reactive power is necessary for the conversion of power through the electric or magnetic field for the operation of inductive electrical equipment (e.g. motors, transformers, etc.). Although reactive power does not perform useful work, consumers are billed for reactive power when it is supplied by their electricity provider. In an electrical system with substantial inductive loads, such as induction motors, consumers can reduce their electricity bills by supplying their own reactive power from capacitors. Apart from a reduction in electricity costs, installing capacitors has several other advantages which include improvement of cable, transformer and motor losses, voltage regulation and capacity reduction of current carrying distribution equipment.

Low Voltage Power Capacitors

Cylindrical MKP type ZEZ Silko capacitors designed for individual, group or central power factor correction in low-voltage networks. The MKP system consists of metallised polypropylene foil with extremely low dielectric losses. The dielectric system is self-healing, in the dry variant. The capacitor types CSADP, CSAKP, CVADP and CVAKP are filled with a vegetable origin solid compact substance that is non-toxic and ecologically harmless. The capacitor types CSADG and CVADG are filled with an inert and ecologically harmless gas. All capacitors are available for voltages up to 800V and 50kVar, and are fitted with discharge resistors and over-pressure devices to safely disconnect failed capacitors from the network.

Low Voltage Automatic Capacitor Banks

Constructed in mild steel cabinets with floor or wall mounting options. Designed to meet individual customer requirements, the banks are equipped with automatic PFC regulators, switching contactors, ZEZ Silko cylindrical capacitors (MKP capacitors, dry-type) and fuses. Main contractors are installed on all banks and consist of either three-phase circuit breakers or fused switches.

Medium Voltage Capacitors

Designed for power factor correction and harmonic filtering in medium voltage networks. The ZEZ Silko capacitors use All Film technology, the dielectric is polypropylene foil impregnated with non-toxic, non-PCB environmentally friendly and biodegradable synthetic oil. Capacitor discharge is effectively achieved by internal discharge resistors that will discharge the capacitor voltage to 75Volt within 10 minutes or to 50Volt within 5 minutes. The capacitor cases and mounting brackets are manufactured from Stainless Steel that is polyurethane coated to ensure prolonged durability. The welded type porcelain bushings are available for various pollution levels to cope with any operating environment. Complying with the requirements of IEC/EN 60871-1 and GOST 1282-88, the capacitors are supplied standard as temperature category -40/C capacitors, which allow for operating in ambient temperatures of up to 50°C. For ambient temperatures up to 55°C, capacitors of temperature category -40/D are available on request. The capacitors are available in Single and Three-Phase design for voltages up to 24kV and 1000kVar, and can be supplied with pressure sensors operating from 230V/50Hz supply voltage.

Medium Voltage Capacitor Banks

Type SCB and ACB are used for individual or central power factor correction in medium voltage power networks. The capacitor banks are constructed in mild steel cabinets according to customer specifications. Standard construction includes ZEZ Silko MV capacitors, three−phase units or single−phase units in star connection or, alternatively, single−phase units in double−star connection. Depending on customer requirements, the capacitor banks can be equipped with inrush current reactors and other protection and measuring elements consisting of unbalance detection relays, detuning reactors and current transformers. For complex technical solutions, automatic capacitor banks are equipped with automatic PFC regulation and vacuum contactors. The capacitor banks are available for voltages up to 22kV and power ratings up to 10MVAr.
The ZEZ Silko capacitor bank type SCA is used for individual or central power factor correction in medium voltage power networks. The capacitor banks are constructed on steel frames according to customer specifications. Standard construction includes ZEZ Silko MV capacitors, three−phase units or single−phase units in star connection or, alternatively, single−phase units in double−star connection. Depending on customer requirements, the capacitor banks can be equipped with inrush current reactors and other protection and measuring elements consisting of unbalance detection relays, detuning reactors and current transformers. The capacitor banks are available for voltages up to 132kV with power ratings on request.

DC Wave Filter and Surge Capacitors (Transnet Approved)

Rated at 3,4kVDC, the 10µF , 20µF and 50µF ZEZ Silko wave filter capacitors are used for harmonic filtering in 3kVDC traction substations. The capacitors are used with resonant shunts to reduce the magnitude of the 6th, 12th, 18th and 24th harmonics at the busbar of the 3kVDC rectifier traction sub-station. The 3kVDC/4µF ZEZ Silko capacitor is used to protect Transnet Freight Rail electrical equipment against surges caused by lightning. The ZEZ Silko capacitors use All Film technology, the dielectric is polypropylene foil impregnated with non-toxic, non-PCB environmentally friendly and biodegradable synthetic oil. Capacitor discharge is effectively achieved by internal discharge resistors that will discharge the capacitor voltage to 50V within 5 minutes. The capacitor cases and mounting brackets are manufactured from Stainless Steel that is polyurethane coated to ensure prolonged durability. The capacitors are supplied standard as temperature category -40/C capacitors, which allow for operating in ambient temperatures of up to 50°C. The wave filter and surge absorber capacitors are Transnet approved and comply with the Transnet Technology Management specifications BBB3139 and CEE0115 respectively.

Induction Furnace Capacitors

These are water cooled power capacitors that are used in induction furnaces and heaters. They improve power factor or tune special furnace circuits. The ZEZ Silko capacitors are made of all-film dielectric, impregnated with environmentally friendly, non-toxic biodegradable insulation oil. They are designed as water cooled live case capacitors with dead case capacitors available on request. Multi tapping configurations that enable high current loading and tuning resonance circuits are standard features.

Surge Capacitors

these are used to limit the surge wave shape to prevent damage to the insulation of MV motors, generators and transformers. The ZEZ Silko surge capacitors are generally used in combination with surge arresters to limit the surge wave shape and magnitude. The capacitors use All Film technology, the dielectric is polypropylene foil impregnated with non-toxic, non-PCB environmentally friendly and biodegradable synthetic oil. Capacitor discharge is effectively achieved by internal discharge resistors that will discharge the capacitor voltage to 75Volt within 10 minutes or to 50V within 5 minutes. The capacitor cases and mounting brackets are manufactured from Stainless Steel that is polyurethane coated to ensure prolonged durability. The welded type porcelain bushings are available for various pollution levels to cope with any operating environment. Complying with the requirements of IEC/EN 60871-1 and IEC/EN 60871-2, the capacitors are supplied standard as temperature category -40/C capacitors, which allow for operating in ambient temperatures of up to 50°C. The capacitors are available as dead-case or live-case design for voltages up to 24kV.

ZEZ Silko Capacitors for Power Electronics

• DC Link Capacitors are used on dc supplies and are intended to protect the network from momentary voltage spikes and surges and for filtering out ac ripple.

• AC Filter Capacitors are used on AC/DC power converters and inverters (drives) that are very common today in the field of power electronics. Traction drives, wind power converters and solar inverters are examples of these applications.
• Damping Snubber Capacitors are used for protecting semiconductors (IGBT transistors). These capacitors are charged and discharged repetitively and carry very high peak currents.

• Medium Voltage DC Capacitors are used on dc supplies and for other general applications in electronic equipment.

Inrush Current Reactors

for indoor and outdoor medium voltage capacitor banks as protection against very high peak inrush currents during switching operations. The ZEZ Silko reactors are rated for maximum operating voltages up to 12kV and 250Amp. Designed as air core reactors, the outdoor reactors are encapsulated in resin.

Detuned Reactors for detuned capacitor banks.

The reactors have high linearity, low losses and minimal noise. Inductance is fixed to the exact value with tolerance of –1/+3%. The ZEZ Silko reactors are designed for capacitors at 7200 V (grid 6000 V) and 12000 V (grid 10000 V), 50 Hz and tuned to a resonance frequency of 189 Hz. Reactors are wound on a Fe core with insulation Class B. Reactors for other voltage, frequency and power are available on request.

Power Factor Correction Controllers type PFR6/PFR12, Super PFR6/12 and NOVAR 1106/1114

These usesthe latest technology and designed for easy and effective regulation. The controllers monitor the power system status and accurately and quickly take decisions on the connection or disconnection of compensation stages in order to reach the pre-set power factor. The controller’s microprocessor records system voltage and current consumption of the entire operation via instrument transformer inputs and uses these to calculate the relationship between active power and reactive power in the power system. The regulator calculates the basic harmonic factor of the active and reactive currents using the FFT algorithm. Thus, precise measurement and control is provided even if the current waveform is distorted by higher harmonic components.

Vacuum Contactors

They are specifically designed for industrial applications where large numbers of switching operations are required. The ZEZ Silko LVC vacuum contactor is optimal for switching capacitor banks from 3,3kV up 6,6 kV.

Current and Voltage Transformers
Intended for measuring and protecting of indoor and outdoor high-voltage distribution systems with voltages from 3,6kV to 40,5KV. The transformers comply with requirements of IEC 60044-1, IEC 60044-2, ČSN EN 60044-1, ČSN EN 60044-2, GOST 1983-89 and DIN 42600/1983.

TP-Series Split-Core Current Transformers

Are especially designed to facilitate installation in new or existing networks. Thanks to the split core design, these current transformers can be installed without opening any cable or busbar circuits. The connection of standard CTs usually requires the interruption of the primary side circuit to pass cables or busbars through the transformer core or to connect such cables to the primary terminals. The ZEZ Silko TP series transformer cores can easily be opened and they can be installed and connected without any supply interruption, saving time and installation costs.