Power capacitors in general

INDEX Power capacitors in general..low VOLTGE CPCITORS MKP (Box )..PPM / MKP TECHNOLOGY..OPERTING CONDITION.. Voltage..mbient temperature.. Installation.. Discharge the capacitor.. Inrush current limitation.. Harmonics.7.Overpresure disconnector.8. Overcurrent / short circuit protection.8. Earthing.. Dielectric.. Insulation.. Cables and Fuses. General Technical Data.Tables for Capacitors - 7-8

LOW VOLTGE CPCITORS MKP (Box ) produce single -phase and three-phase power capacitors for power factor correction These Capacitors are produced in MKP systems. dielectric systems are self healing. Metal plated layer is evaporated in case of the voltage breakdown. Formed insulating surface is very small and does not effected the functionality of the capacitor. Capacitors windings are inserted into steel box sheet coated with a layer of tin that protects the steel from corrosion. Container is equipped with the overpressure disconnector.mkp capacitors are made of one side metalized PPM film. Contacting of the winding is performed by zinc spraying. This configuration is dry.. PPM / MKP TECHNOLOGY Metalized polypropylene technology ( PPM MKP ) utilizes a vacuum evaporation technique to deposit an extremely thin layer of metal on one side polypropylene film. The capacitor elements built using this technology are obtained by winding two propylene films. The capacitor plate consist of the metalized surface of the two films and the dielectric is the propylene film itself. The main advantage of capacitors with metalized plates is their self-healing capacity. This means that they are capable of restoring their electrical properties following the occurrence of a short circuit between the plates. Due to the reduced thickness of the plates, the short circuit current generated area of a fault is capable of vaporizing the metal coating. The short circuit as thereby automatically extinguished without an appreciable reduction in capacitance or expenditure energy. OPERTING CONDITION Temperature, voltage and current must be carefully controlled in order to obtain optimum result as regards the lifespan of the capacitor, as following : Voltage : The capacitor are worked continuously at rated voltage ( Un ). More than quantity maximum over voltage for the capacitor as following: +% Un for 8 hours every hours + % for 0 minutes every hours +0% for minutes every hours +0% for one minute every hours Overvoltage in excess of >% should not occur more than 00 times during life of capacitor. Table( )MXIMUM PERMISSIBLE VOLTGE

mbient temperature The ambient temperature category for most standard types is /D. This means a max. temperature of C, an average temperature over hours of C, and the average temperature in one year should not exceed C. The maximum casing temperature of 0 C must not be exceeded. Temperature is one of the main stress factors for polypropylene type capacitors. Temperature has a major influence on the useful life expectancy of the capacitor. For higher temperature requirements, as Table( ): Table()COOLING IR TEMPERTURE LIMITS Installation Before installing the capacitors it is necessary to check carefully the current Harmonic distortion in the power system. If non-linear load on your electrical system exceeds % of the total load, you can suffer from harmonic contaminated network. Capacitors are suitable for indoor installation, for any mounting position. utomatic capacitor banks must be equipped with a cooling fan, activated when the internal temperature exceeds the set value ( normally ºC ). utomatic capacitor banks should be completed with suitable capacitor switching contactors, equipped with pre-making ( necessary to protect capacitors from inrush peak currents during switching operation ) Scheduled periodic checks and inspections are mandatory to assure capacitors reliable operation Discharge the capacitor Before re-switching, capacitors must be discharged to % of the rated voltage or below. discharge resistor can be easily replaced by pushing it onto the exposed top on the terminal. ( minute / 0 V ) Inrush current limitation Switching LV PFC capacitors can cause high inrush currents of more than 00 times the rated current, especially when they are connected in parallel to others that are already energized. This may cause additional stress to contactors as well as to capacitors and reduce their life cycle. Inrush currents have a negative effect on power quality, e.g. transients, voltage drop. MKP-designs feature high impulse handling capability, inrush current limitation is required, e.g. contactors with precharging resistors for pre-loading of capacitors. Harmonics Harmonics are voltages and currents with frequencies that are different from a 0 Hz or 0 Hz power supply frequency. Harmonics result from the operation of electrical loads with non-linear voltage-current characteristics. They are mainly caused by loads operated with modern electronic devices, such as converters, electrical drives, welding machines and uninterruptible power supplies (UPS). Ensure that the current through the capacitor doesn t exceed the limits given in the specific data sheets. Ensure that the voltage doesn t exceed. Un and the peak voltage doesn t exceed. Un. Use a true rms and peak voltmeter or oscilloscope to check it.

Overpressure disconnector Electrical components do not have unlimited life expectancies; this also applies to self-healing capacitors. s polypropylene-type capacitors seldom produce a pronounced short circuit, HRC fuses or circuit breakers alone do not offer sufficient protection. ll capacitors of the models are consequently fitted with a disconnector that responds to overpressure. If numerous electric breakdowns occur at the end of life or as the result of thermal or electric overload (within IEC 08 specification), the formation of gas causes the pressure inside the capacitor case to rise. This causes a change in length because of curvature of the lid or stretching of the expansion bead. Expansion beyond a certain degree will separate the internal wires (tear-off fuses) and disconnect the capacitor from the line. Overcurrent / short circuit protection HRC fuses or moulded case circuit breakers ( MCCBs ) for short circuit protection have to be used. Short circuit protection equipment and connection cable should be dimensioned to handle the. times rated current of the capacitor permanently. Selection of connection cables should be dimensioned according to handling of current (for recoendations, refer to the appendix). HRC fuses do not protect the capacitor against overload. They are only a short circuit protection! MCCBs and HRC fuse rating has to be.....8 times nominal capacitor current. Do not use HRC fuses for switching capacitors (lightning arc!). Use thermal/magnetic over current relays for overload protection. Earthing Capacitors with a metal case must be earthed at the mounting stud ( M ) or by means of a separate metal strap or clamp. Dielectric MKP-/MKPg-type capacitors are based on a low-loss dielectric formed by pure polypropylene film. thin self-healing mixture of zinc and aluminum is metalized directly on one side of the PP-film under vacuum. Our long-term experience as well as on-going research and improvements in this technology ensure the excellent self-healing characteristics of the dielectric and a long operating life of our capacitors. The plastic film is wound into stable cylindrical windings on the most modern automated equipment. The ends of the capacitor windings are contacted by spraying with a metal contact layer, facilitating a high current load and ensuring a low-inductance connection between the terminals and windings. Insulation The use of impregnants and/or filling materials in capacitors is necessary in order to insulate the capacitor electrodes from oxygen, humidity, and other environmental interference. Without such insulation, the metal coating would corrode, an increasing number of partial discharges would occur, the capacitor would lose more and more of its capacitance, and suffer increased dielectric losses and a reduced operating life. Therefore, an elaborate vacuum-drying procedure is initiated iediately after insertion of the capacitor elements Cables and Fuses Dimensioning of the connection cables and protection fuses of power capacitors is made from their rated current. Rated current of the capacitors is printed in their characteristics plate. Fuses Due to the high connection overcurrents, fuses must be calibrated to a value of. to times the rated current of the capacitor to protect. Cables Feeding cables of the capacitors must be dimensioned at taking into account that their rated current can be increased even up to a 0% in the case of harmonics. The cross-section values listed below are guideline values valid for operation under normal conditions and at an ambient temperature of 0 C. Higher values should be selected if conditions differ from normal, such as higher temperatures or harmonic distortion

C power (00 V) Q (kvar) Current input per phase (00 V) I () Supply line Cu (²) Fuse protection slow-blowing x I () 0... 7...7 0 0. 0 0 0 70 7 80 0 0 0 0 80 00 0 00 0 00 0 00 0.7...88.0..7 7.0 8..80.0 8.00.0.00 8.80.00.0 8.00 0.0 7.0.80 7.00 8.0 0 0.80 0 8.00..0.00 7.80 8 0.00.00.0 8 8.00 0.00.00 0.00 7.00 8.00 7 0.00 x. x. x. x. x. x. x. x. x. x. x. x x x x x x x x x x / x 0/ x 0/ x 70/ x 70/ x / 0 x / 0 x / 0 x 0/ 70 x 0/ 70 x 0/ 70 x 0/0 x 0/0 x x 0/ 70 x x 8/ x x 0/0 x x 0/0 x x 0/ 70 x x 0/ 70 0 80 80 80 0 0 0 0 00 00 0 0 0 00 00 00 0 x 00 x 00 x 00 x 00 Cables and fuses Table( ) for other three phase voltage ratings The cross-section values are multiplied as following: 0 V table figure.7 0 V table figure 0. 80 V table figure 0.8 V table figure 0.7 lower cross section is normally sufficient for the internal wiring of a capacitor bank. Various parameters such as the temperature inside the cabinet, the cable quality, the maximum cable isolation temperature, as well as the type (single or multicore) and length of the cable have to be taken into consideration when selecting the appropriate value.

General Technical Data Table() Rated voltage Frequency Over voltages Over current Inrush current Losses (dielectric) Capacitance tolerance Test voltage terminal to terminal Test voltage terminal to Case Life expectancy Cooling mbient temperature category Permissible max humidity Maximum permissible altitude Mounting position Mounting and grounding Safety features Discharge resistors Case Degree of protection Impregnation Terminals Installation Standards UN(V) F(HZ) U Imax Is 0 V single phase,00,,0, V three phases 0/0HZ UN+%(up to 8h daily)/un+%(up to 0 min daily). UN +0%(up to min daily)/ Min.. IN 00 times rated current 0.0 W/KVar -%/+% UTT.*UN, C, S UTC Up to UN= 0V:000VC, s;above UN=0V:000 VC, s TLD(CO) 0,000 operating hours Naturally air-cooled (of forced air cooling) LCT/ -/D, max, Ċ, with forced cooling conditions higher ambient UCT temperature possible. Hrel % Max 000 M above sea level ny position, normal stand mounting Threaded M stud on bottom of case Dry technology, overpressure/current disconnector, self-healing, Internal discharge module design included in delivery, (<0V within min) steel box sheet coated with a layer of tin that protects the steel from corrosion IP0, indoor mounting (optionally with cover for Ip) Non-PCB, with resin Dual, with electric shock protection, max, cross-section cable Indoor and outdoor (with the cover) IEC08-+, TS EN08-+, VDE00-+7, CE

0 V SINGLE PHSE LOW VOLTGE BOX TYPE CPCITOR KRK-0,-0-P-B KRK-0,-0-P-B KRK--0-P-B KRK-,-0-P-B KRK--0-P-B KRK-,-0-P-B KRK--0-P-B KRK--0-P-B KRK--0-P-B KRK-7,-0-P-B KRK--0-P-B CP 0, 0,,, 7,,7,,, 8,,7, 7,,, 0, 0,,,8,,,8,,, 7,7,,, 0,,8 8,7,, 0, 0, 0, 0 0, 80 0 0 0 00 Table ( ) 00 V SINGLE PHSE LOW VOLTGE BOX TYPE CPCITOR KRK-0,-00-P-B KRK--00-P-B KRK-,-00-P-B KRK-,-00-P-B KRK--00-P-B KRK-7,-00-P-B KRK--00-P-B KRK-,-00-P-B KRK--00-P-B KRK-0-00-P-B KRK--00-P-B KRK-0-00-P-B KRK-0-00-P-B KRK-0-00-P-B CP 0,,, 7,, 0 0 0 0 0,7,,, 7,,8, 8,0, 8,8,0, 70 0,,,8 8 0 8 0 0,,7,, 8,,0 7,,,,,,8 7, 8 x, x, x x,7 x, x0 x, x8 x x x x00 x x0 x7x0 x7x0 x7x0 Table ( ) 7

V THREE PHSE LOW VOLTGE BOX TYPE CPCITOR KRK-0,--P-B KRK---P-B KRK-,--P-B KRK-,--P-B KRK---P-B KRK-7,--P-B KRK---P-B KRK-,--P-B KRK---P-B KRK-0--P-B KRK---P-B KRK-0--P-B KRK-0--P-B KRK-0--P-B 0,,, 7,, 0 0 0 0 0,7,,, 7,0,8, 7, 0, 7,8,8,7,, 0,,,8 8 0 8 0 0,,7,, 8,,0,7 0,,,,8 0,0,7 8, CP x, x, x, x, x0, x, x,7 x77, x, x x x8 x x07 x7x0 x7x0 x7x0 Table ( 8 ) 0 V THREE PHSE LOW VOLTGE BOX TYPE CPCITOR KRK-0,-0-P-B KRK--0-P-B KRK-,-0-P-B KRK-,-0-P-B KRK--0-P-B KRK-7,-0-P-B KRK--0-P-B KRK-,-0-P-B KRK--0-P-B KRK-0-0-P-B KRK--0-P-B KRK-0-0-P-B KRK-0-0-P-B KRK-0-0-P-B 0,,, 7,, 0 0 0 0 0,7,,0,,,8,,,7,,8,,, 0,,,8 8 0 8 0 0,,,,0 7,,8,7,8,,, 7,,0 7, CP x,7 x, x8, x,7 x7, x, x, x8, x8, x x7 x, x x78 x7x0 x7x0 x7x0 Table ( ) V THREE PHSE LOW VOLTGE BOX TYPE CPCITOR KRK-0,--P-B KRK---P-B KRK-,--P-B KRK-,--P-B KRK---P-B KRK-7,--P-B KRK---P-B KRK-,--P-B KRK---P-B KRK-0--P-B KRK---P-B KRK-0--P-B KRK-0--P-B KRK-0--P-B 0,,, 7,, 0 0 0 0 0,,,7,8, 8,,8, 7, 0,,,8 8 0 8 0 Table ( ) 8 0,7,,,,,,8,,,8 CP x, x, x,8 x,7 x, x8, x8, x8, x7,8 x77, x, x x x x7x0 x7x0 x7x0