7/28/2019 Usm Reactors
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Reactor
A consumer whose load includes a high proportion of variable
speed motor drives and/or other harmonic generating loads may
require a
detuned capacitor system. This would perform the function of
power factor improvement whilst preventing any amplification of
harmonic
currents and voltages caused by resonance between capacitors and
inductances in the mains.
USM offers single and three phase filter reactors for this
purpose. The low-loss reactors are made of specially selected tra
nsformer sheets
and manufactured in flat or round copper wire technology.
They are dried and impregnated in a vacuum which ensures they
can withstand high voltages and maintain a long operating life.
Depending
on their rated power. the reactors are provided with either
terminal blocks or terminal lugs/cables.If the operating
temperature of 120
oC is exceeded, the reactor circuit is disconnected by a thermal
switch(included as standard).
Reactor for Detuned Capacitor BanksConstruction
Adjusted rating
The adjusted reactor is designed to create exactly the
required
output of reactive power, allowing for the internal voltage rise
inside
the resonating circuit formed together with the capacitor
connected
in the circuit. Note that exact sizing of the capacitor is
necessary.
Non-adjusted rating
The non-adjusted reactor is matched to a power capacitor
with
standard rating at mains voltage.
This allows for additional installation of detuning reactors in
existing
non-detuned systems, however, it will lead to increased output
of
kvar due to voltage rise inside the resonance circuit.
Example
25kvar 400V 60Hz, detuned to 245Hz(p=6%)*
capacitor:capacitance of standard capacitor: 414 F (3 138 F)
reactor:
required reactance of the reactor: XL = XC p= 6.4 0.06 =
0.384
Example
25kvar 400V 60Hz, detuned to 245Hz(p=6%)*
capacitor:
required reactance of the reactor:
XL = XC p= 6.82 0.06 = 0.41
* Simplified calculation (single phase)
* tuning frequency: 189Hz (p=7%, 50Hz), 227Hz (p=7%, 60Hz)
204Hz (p=6%, 50Hz), 245Hz (p=6%, 60Hz)
Pcurrent for PFC 25kvar 400V 60Hz: 1 = = 62.5A
U
Uvoltage at capacitor terminations: UC = = 426V
1-p
1adjustment of the capacitance: C = = 389
UC 2 f
reactor:1
reactance of the capacitor: Xc = = 6.822 f C
XLrequired inductance: L = = 1.09mH
2 f
1reactance of the capacitor: Xc = = 6.4
2 f C
XLrequired inductance: L = = 1.02 mH
2 f
resulting PFC current: Xtotal = XC - XL = 6.02
U 400VI = = = 66.7A
Xtotal 6
Q= U I = 26.7 kvar
Design three phase, iron core, double air gapCore Grain-oriented
cold rolled electrical steel
Protection class IP00, indoor mounting
Insulation class H class
Cooling natural cooling
Winding material Double enamelled copper wire. insulation class
"H"
Impregnation standard dip varnish coating
Terminals terminal blocks, cable lags, or temperature-proof
flexible cables
Insulation winding to core 3 kv, nomex aramid paper
temperature class c (220oC)
Temperature monitoring temperature switch, response class
120oC
Adjustment accuracy L=+3%
Standards VDE 0570 Part 2 / IEC 96/104/CD
Tolerance of inductance 3%+_
Load Losses
