Automatic devices for reactive power compensation
Our devices are designed according to the latest technical trends and are characterized by their compactness and modular construction system.
The equipment is built into high-quality self-supporting cabinets manufactured in Evrotehna – Kraljevo. The cabinets are made in IP55 protection of steel sheet 1.5 mm thick and are electrostatically plasticized with polyester structural powder (commonly: RAL 7035 or as desired by the customer). The picture shows our standard solution for maximum power up to 1200kVAr. The cabinets are located on the platforms through which the power cables are joined into the lower part of the cabinet. The cabinets are mechanically interconnected – a modular system. Door locking is done in four phases and the choice of the cylinder is at customer’s request. The ventilation of the cabinet is done through a thermostatically controlled suction filter fan and an exhaust grill located on the top of the cabinet. In this way adequate cooling of the equipment is provided and the dust drop is prevented.
Built-in equipment is of the highest quality manufactured in Western European countries and is selected according to the quality of manufacturers and their references.
- Capacitors ELECTRONICON GmbH Germany (the capacitor which is the most important and the most demanding part of the device has been produced in the previously mentioned factory for over 70 years)
- Filter chokes ELECTRONICON GmbH Germany
- Contactors ELECTRONICON GmbH Germany (B&J Austrija)
- Electronic regulator ELECTRONICON GmbH Germany , website: www.electronicon.com
- NV fuses and disconnectorsM.Schneider/Mersen Germany, website: www.mschneider.at
- Ventilators and thermostats Schrack Technik GmbH Germany, website: www.schrack.com
- Distribution cabinets and additional assembly equipment Evrotehna d.o.o. – Kraljevo, website: www.evrotehna.com
Equipment in cabinets:
The capacitor we install is MKPg capacitor. MKPg denotes a capacitor that contains a metallized PP film and is filled with gas. These capacitors are based on dielectric with small losses – a pure polypropylene (PP) film. On the aforementioned PP film, in a vacuum environment, a thin layer of zinc and aluminum mixture is applied by the metallization process. The capacitors are filled with a non-toxic inert insulating gas which mainly consists of nitrogen (N2). It also does not contain SF6 gas nor any other toxic nor banned substance as well. This technology has proven to be a winning combination in terms of the characteristics and life expectancy of the Electronicon capacitor.
Connecting electrical conductors to the capacitor is carried out via the CAPAGRIP ™ terminal developed by Electronicon. In this way it is performed quickly and safely on all types and sizes of the capacitor.
Characteristics, testing and application of the capacitor is compliant with IEC60831, UL810 and CSA22.2. standards. All capacitors of working voltage up to 660V rms have been tested and approved by the CSA organization and meet the UL and CSA standards.
The working voltage and the power of the capacitor are determined based on our structural analysis and measuring.
A plant that contains a large number of electronic regulators of motor drives creates more current harmonics and voltage. In order to prevent this resonance, i.e. enhancing the existing harmonics between the capacitor and the grid into the electric circuit, a filter choke is connected.
The choke windings are made of copper or aluminum conductors, round or rectangular wire, while the connection is always copper. Chokes are made from 1.25kVAr up to 100kVAr and voltage up to 690V. The whole choke is vacuum impregnated with electrically insulating varnish and equipped with a thermal fuse (overheating protection).
The most commonly used regulator series is the PFR-X. The regulator calculates the active and reactive power based on the measured voltage and current phases of the main connection, and then activates/ deactivates the output compensation levels. The regulator automatically optimizes the number of shutdowns according to degrees and “rotates” them (the degrees) so that the whole equipment is used equally. The integrated digital display can show the current power factor, grid frequency, previously set power factor, power of the capacitor, etc. Also, the regulator has various adjustable alarms. There are 6–12 outputs which can be relay or transistor.
Disconnectors of the NV fuses:
We protect each compensation level with low-voltage, high-performance fuses which are assembled into disconnectors. The fuses and disconnectors are made by M Schneider – Mersen. We install disconnectors designed for assembly of copper bus bars in our cabinets. The manufacturer guarantees high quality materials and reliability, possibility of visual and electric control of the fuse condition (transparent door and holes for electrical measuring) without opening the disconnector doors, as well as the possibility of their secure sealing.
Filter fans and thermostats:
ZFor adequate cooling of equipment we use industrial quality fans with an inlet air filter. The life expectancy is about 40,000 hours. The fans are directly connected to the adjustable thermostats of the temperature range 10-60C. The flow and size of the fan is determined by analysis depending on the thermal losses, the size of the cabinets and other parameters.
Depending on the need, i.e. the type of load, we produce compensation cabinets in contactor, thyristor and hybrid options (combination of contactor and thyristor). We also determine which types of capacitors and filter chokes we will install based on measuring and analysis.
The following pictures present our cabinets in hybrid design:
The picture shows the detail of the cassette construction of the cabinet, front view. On the front side there are NV fuses, contactors for switching on the capacitor and power supply of the cassette made by copper bus bars. Filtered chokes and capacitors are placed in the cassette. The construction of the cassette provides the possibility of quick dismantling of parts and facilitates access to the cooling air.
The picture shows a side view of a cassette level of the compensation plant consisting of three cabinets.
Cassette cabinet construction (in the installation phase) with thyristor-controlled compensation. Thyristor blocks shown in the picture are also manufactured by Electronicon and are designed to turn on the power of 50kVAr.
– Devices are designed as a modular construction system which allows easy upgrading (power boost) without additional costs for new regulations.
– The typical power of a cabinet unit is up to 300 kVAr and the maximum of 400kVAr (by installing an additional 100kVAr cassette).
– Monitoring the operation of the remote device (optional).
– Long lasting of the device – the minimum life expectancy of the capacitor is 150,000 hours.
– The warranty on the complete device and built-in elements is three years.
– Complete testing of the device before installation.
– Durable and safe work.
– The ability to activate various types of alarm.
– Possibility to monitor all electrical quantities in the factory/plant and their recording (option).
– Complete automatic operation of the devices.