Three Phase Capacitors KNK

Transcription

1 Three Phase Capacitors KNK Features Connection profile Φ 90 and 116 mm 2-16 mm 2, Φ 136 mm 2-25 mm 2 *Use of flexible conductors only with ferrules Capacitors equipped with discharge resistors Rated power from 2,5kVAr to 50 kvar Overpressure protection Rated voltages[v]: 400, 440, 460, 480, 525 The possibility of mounting a capacitor bank in a horizontal position (only KNK 1053) 108

2 Three Phase Capacitors KNK Applications - The KNK capacitors are used for power factor correction of inductive consumers (transformers, electric motors, rectifiers in industrial networks). Available Versions of KNK Capacitors Indoor mounting: KNK three-phase in cylindrical housing KNK three-phase in cylindrical housing - DRY type Design Cylindrical aluminium housing with metallized three-layer polypropylene film dielectric, especially treated for better contact. the capacitors are: a. impregnated with polymerized a vegetable oil which is PCB-free and biologically degradable, b. DRY type - patented Ordering: - capacitor type - capacitor power - rated voltage - rated frequency - quantity and delivery terms Ordering example for three-phase 25 kvar capacitor at 400 V: KNK1053, 25 kvar, 400 V,. 109

3 Routine Testing of Capacitors Capacitors are subjected to the following tests during the production process: - sealing test (90 C, 6 hrs) - voltage tests between layers with AC voltage equal to 2,15 Un, 2 s - voltage test between layers and the housing with AC voltage 3600 V, 2 s - measurement of loss angle tanδ at a rated voltage, frequency of, and room temperature - measurement of capacitance at a rated voltage, frequency of, and room temperature Over-Pressure Disconnector Every capacitor incorporates a mechanical over-pressure disconnector which disconnects the capacitor in case of overloading or other internal damages. Operation is shown in figure 1. Discharge Resistor Every capacitor incorporates a resistor which serves for capacitor discharging after network disconnection to 75 V in 3 minutes. Self-Healing Capacity Damage may occur on the dielectric due to fatigue which results in local breakdowns on certain points. the resultant electric current devaporises the thin metallized layer and isolates the damaged spot from the rest of the capacitor. Capacitance loss is almost negligible (some pf) during this process. this self-healing property guarantees operating reliability and long life expectancy of the capacitor. Figure 1 Self-healing of KNK capacitors 1. metallized layer 2. polypropylene film 3. breakdown point 4. devaporised metallized layer 110

4 Three-phase capacitors KNK 5065 Technical data: Rated voltage Un Rated frequency 400, 440, 460, 480, 525 V Capacitance tolerance - 5% to + 15% Losses: - Dielectric < 0,2 W/kVAr - Total < 0,5 W/kVAr Safety Discharge 50Hz self-healing, overpressure disconnector 3 min. to 75 V Standard IEC /2 Dielectric and filling Permitted ambient temperature Permitted storage temperature Max. allowable operating voltage and current In-rush current (max.) Test conditions metallized polypropylene film sealed with plant oil; PCB-free C to C C to C 1,1 Un (8 h per day) 1,5 In 150 In - between layers 2.15 x Un AC 2 s - layers-housing 3.6 kv AC 2 s Rated voltage and frequency Rated power Code No. Rated capacitance (µf) Rated current (А) Height Н (мм) Weight (kg) Packaging unit(pcs) 400 V 440 V 460 V 480 V 525 V *60 Hz on request 2, х 16,6 3, ,45 1/ х 19,9 4, ,45 1/ х 26,5 5, ,55 1/ х 33,2 7, ,55 1/36 2, x 13,7 3, ,45 1/ x 16,5 3, ,45 1/ x 21,9 5, ,55 1/ x 27,4 6, ,55 1/36 2, х 12,5 3, ,45 1/ х 15,0 3, ,45 1/ х 20, ,55 1/ х 25,1 6, ,55 1/36 2, х 11, ,45 1/ х 13,8 3, ,45 1/ х 18,4 4, ,55 1/ х 23, ,55 1/36 2, x 9,6 2, ,45 1/ x 11,5 3, ,45 1/ x 15,4 4, ,55 1/ x 19,3 5, ,55 1/36 111

5 Three-phase capacitors KNK 1053 (dry) Technical data: Rated voltage Un Rated frequency 400, 440, 460, 480, 525 V Capacitance tolerance - 5 % to + 15 % Losses: - Dielectric < 0,2 W/kVAr - Total < 0,5 W/kVAr 50Hz Degree of protection IP 20 Discharge 3 min. to 75 V Standard IEC /2 Safety Dielectric and filling self-healing, overpressure disconnector metallized polypropylene film Permitted ambient temperature - 25 C to + 55 C Permitted storage temperature - 40 C + 70 C Max. allowable operating voltage and current In-rush current (max.) Test conditions 1,1 Un (8 h per day) 1,5 In 200 In - between layers 2.15 x Un AC 2 s - layers-housing 3.6 kv AC 2 s 112

6 Three-phase capacitors KNK 1053 (dry) Rated voltage 400 V 440 V 460 V 480 V 525 V *60 Hz on request Rated power Code No. Rated capacitance (µf) Rated current (А) Dimensions Weight (kg) Packaging unit(pcs) Height(mm) Φ (mm) x 66,3 14, ,20 1/16 12, x 83, ,20 1/ x , ,40 1/ x , ,60 1/ x 165,8 36, ,90 1/ x 198,9 43, ,30 1/ x 265,0 57, ,50 1/ x 331,5 72, ,50 1/ x 54,9 13, ,20 1/16 12, x 68,6 16, ,20 1/ x 82,3 19, ,40 1/ x 110,0 26, ,60 1/ x 137,1 32, ,90 1/ x 164,4 39, ,30 1/ x 219,0 52, ,50 1/ x 274,0 65, ,50 1/ x 50,1 12, ,20 1/16 12, x 62,7 15, ,20 1/ x 75,2 18, ,40 1/ x 100,3 25, ,60 1/ x 125,4 31, ,90 1/ x 150,4 37, ,30 1/ x 200,6 50, ,50 1/ x 250,7 62, ,50 1/ x 46, ,20 1/16 12, x 57, ,20 1/ x 69, ,40 1/ x 92, ,60 1/ x 115,1 30, ,90 1/ x 138,2 36, ,30 1/ x 184, ,50 1/ x 230, ,50 1/ x 38, ,20 1/16 12, x 48,1 13, ,20 1/ x 57,7 16, ,40 1/ x 77, ,60 1/ x 96,2 27, ,90 1/ x 115, ,30 1/ x 154, ,50 1/ x 192, ,50 1/

7 Individual Power Factor Correction for Low Voltage Motors Power rating of capacitor in (kvar) with respect to motor power, speed of rotation and load Rated motor 3000 r / min 1500 r/min 1000 r/min 750 r/min 500 r/min power [kw] No load No load No load No load No load 5,5 2,2 2,9 2,4 3,3 2,7 3,6 3,2 4,3 4 5,2 7,5 3,4 4,4 3,6 4,8 4,1 5,4 4,6 6,1 5,5 7, ,5 5,5 7, , ,5 8,5 7 9, , , , It is useful to compensate rarely switched low voltage motors with a fixed connected capacitor due to technical and cost reasons. Description - The required capacitor power is calculated with the following formula: Q n = 0,9 I mag 3 where: Q n - capacitor power (var) - rated voltage (V) I mag - motor magnetising current (A) Quick discharging with a bigger capacitor can cause self-excitation. If quick discharging of the motor is not possible, the motor can compensate itself according to the actual consumption of reactive power. Capacitor power versus working voltage Capacitor working power depends on working voltage (U e / ) 2 Q с = Q f where: U e - mains voltage; - capacitor rated voltage Q с - capacitor power at rated voltage Q f - capacitor actual power Rated voltage 400 V 50 HZ 440 V Rated capacity (µf) Rated Power at = 380 V Rated Power at = 400 V Rated Power при = 420 V Rated Power at = 440 V 3 x 16,6 2,3 2, x 19,9 2, x 26,5 3, x 33,2 4, x 66,3 9, x 83,3 11,3 12, x , x 133,0 18, x 165,8 22, x 198,9 27, x 13,7 1,9 2,1 2,3 2,5 3 x 16,5 2,2 2,5 2,7 3 3 x 21,9 3,0 3,3 3,6 4 3 x 27,4 3,7 4,1 4,6 5 3 x 54,9 7,5 8,3 9, x 68,6 9,3 10,3 11,4 12,5 3 x 82,3 11,2 12,4 13, x 110,0 14,9 16,5 18, x 137,1 18,6 20,7 22, x 164,4 22,4 24,8 27,

8 Power Factor Correction for Power Transformers Power ratings of capacitor in (kvar) with respect to primary voltage and load Rated power 5-10 кv кv кv of transformer (kw) No load No load No load 5 0,75 1 0,8 1,1 1 1,3 10 1,2 1,7 1,5 2 1,7 2, ,5 3, ,5 3, The total correction power required in distribution transformers is 4 % to 5% of rated power at an average load of 70 %. Direct correction on only self-use transformers is rarely useful. In that case the capacitor has a fixed connection to a secondary of transformer. The power of the capacitor is chosen to compensate the full load of the transformer. Data from Table are used for orientation. Usually the fixed capacitor is also chosen to compensate for the power network and small uncorrected consumers. Table definition of reactive power capacitor bank, necessary to achieve a desired cos The value of factor K read from table should be multiplied with the value of active power to determine kvar required for power factor correction. Capacitive reactive power is calculated by formula: Q c = P K P real power of the load cos 0 cos the system without power factor correction cos 1 required cos achieved with power factor correction Q с reactive power of compensation system K factor read from table defined by cos 0 and cos 1 (see table bellow) Existing power factor Required power factor cos 1 cos 0 0,7 0,75 0,8 0,82 0,84 0,86 0,88 0,9 0,92 0,94 0,96 0,98 1,00 0,5 0,71 0,85 0,98 1,03 1,09 1,14 1,19 1,25 1,31 1,37 1,44 1,53 1,73 0,52 0,62 0,76 0,89 0,94 1 1,05 1,1 1,16 1,22 1,28 1,35 1,44 1,64 0,54 0,54 0,68 0,81 0,86 0,91 0,97 1,02 1,07 1,13 1,2 1,27 1,36 1,56 0,56 0,46 0,6 0,73 0,78 0,83 0,89 0,94 1 1,05 1,12 1,19 1,28 1,48 0,58 0,38 0,52 0,65 0,71 0,76 0,81 0,86 0,92 0,98 1,04 1,11 1,2 1,4 0,6 0,31 0,45 0,58 0,64 0,69 0,74 0,79 0,85 0,91 0,97 1,04 1,13 1,33 0,62 0,25 0,38 0,52 0,57 0,62 0,67 0,73 0,78 0,84 0,9 0,97 1,06 1,27 0,64 0,18 0,32 0,45 0,5 0,55 0,61 0,66 0,72 0,77 0,84 0,91 1 1,2 0,66 0,12 0,26 0,39 0,44 0,49 0,54 0,6 0,65 0,71 0,78 0,85 0,94 1,14 0,68 0,06 0,2 0,33 0,38 0,43 0,48 0,54 0,59 0,65 0,72 0,79 0,88 1,08 0,7 0,14 0,27 0,32 0,37 0,43 0,48 0,54 0,59 0,66 0,73 0,82 1,02 0,72 0,08 0,21 0,27 0,32 0,37 0,42 0,48 0,54 0,6 0,67 0,76 0,96 0,74 0,03 0,16 0,21 0,26 0,32 0,37 0,42 0,48 0,55 0,62 0,71 0,91 0,76 0,11 0,16 0,21 0,26 0,32 0,37 0,43 0,49 0,56 0,65 0,86 0,78 0,05 0,1 0,16 0,21 0,26 0,32 0,38 0,44 0,51 0,6 0,8 0,8 0,05 0,1 0,16 0,21 0,27 0,32 0,39 0,46 0,55 0,75 0,82 0,05 0,1 0,16 0,21 0,27 0,34 0,41 0,49 0,7 0,84 0,05 0,11 0,16 0,22 0,28 0,35 0,44 0,65 0,86 0,05 0,11 0,17 0,23 0,3 0,39 0,59 0,88 0,06 0,11 0,18 0,25 0,34 0,54 0,9 0,06 0,12 0,19 0,28 0,48 0,92 0,06 0,13 0,22 0,43 0,94 0,07 0,16 0,36 115

9 Fuse and Connection Capacitor Rated power Qn Capacitor Rated current In(A) 400V, 50Hz 525V, 50Hz 690V, 50Hz Fuse gl/gg =500V (A) Wire cross section Cu(mm 2 ) Capacitor Rated current In(A) Fuse gl/gg =690V (A) Wire cross section Cu(mm 2 ) Capacitor Rated current In(A) Fuse gl/gg =1000V (A) Wire cross section Cu(mm 2 ) 2,5 3,6 10 5,5 2,7 10 1,5-10 1,5 5 7,4 16 2,5 5,5 10 1,5 4,2 10 1,5 7,5 10,8 20 2,5 8,3 16 2,5 6,3 10 1, ,4 25 4,0 11,0 20 2,5 8,4 16 2,5 12,5 18,1 32 6,0 13,8 32 2,5 10,5 20 2, ,6 35 6,0 16,5 25 4,0 12,5 20 2, , ,0 22,0 35 6,0 17,0 32 4, , ,0 27, ,0 21,0 35 6, , ,0 33, ,0 25,0 50 6, , ,0 44, ,0 33, , , ,0 55, ,0 42, , , ,0 66, ,0 50, , , ,0 82, ,0 63, , , ,0 88, ,0 67, , , ,0 110, ,0 84, , Values in the table (approximations) are valid for normal operation (ambient temperatures up to 40 C, in the absence of harmonic distortion in the network, etc.). If conditions exceed rules, higher values shall be choosen. The rated current of the capacitor at different voltages can be determined on the corresponding coefficients: (230V / 440V / 480V / 525V ). The values also depend by: the temperature inside the cabinet, cable quality, the maximum temperature of the cable insulation, the use of single-or multi-core cables, as well as its length Calculations Three-phase capacitor power: Example: 3 x 331.5μF at 400V/50Hz ² = 50 kvar The resonant frequency (fr) and filtering factor (p) in systems with compensation filters: Example: for p = 0.07 at ; fr = 189 Hz The calculation of the power factor cos : Three-phase capacitor power with detuning reactor in series Example: 3 x 331.5μF at 400V/50Hz at p = 7% ² / = 53.8 kvar Phase current of capacitor: Example: 25 kvar at 400V / ( ) = 36 A V = Rated voltage (V) I = Rated current (A) fn = Line frequency (Hz) fr = Resonance frequency (Hz) p = Filtering factor Qc= Capacitor power (VAr) C = Capacitance (F, farad) P = Active power (W) S = Apparent power (VA) Q = Reactive Power (VAr) 116