Download DYNAMIC Power Factor Correction

DYNAMIC
Power Factor Correction
EPCOS AG FK PM PFC (RM)
DYNAMIC PFC
30.04.2003
Page: 1
Target Applications:
Welding / spot welding equipment
Presses (e.g. most car factories in Germany
use meanwhile dynamic PFC)
Wind turbines
Container cranes
Lifts
Central motor start up compensation
Any fast fluctuating load requires DYNAMIC PFC
EPCOS AG FK PM PFC (RM)
DYNAMIC PFC
30.04.2003
Page: 2
What is DYNAMIC PFC?
The usage of new technologies in modern industry claims for faster and more
dynamic power factor correction banks that follow the faster process and allow
a “real time” power factor correction. The solution is the so called “Dynamic
Power Factor Correction”. Dynamic PFC systems use electronic switches rather
than contactors – thyristor modules – which allow an infinite number of
switching operations on one hand and ensures an extremely fast reaction time
upon load changes. High inrush currents one of the big problems while
switching shunt capacitors with conventional contactors are eliminated with
Thyristor switches due to ZERO
CROSSING SWITCHING, means the
capacitor is connected during ZERO crossing of the sinusoidal wave and
therefore no inrush currents are caused.
EPCOS AG FK PM PFC (RM)
DYNAMIC PFC
30.04.2003
Page: 3
Customer benefits of DYNAMIC PFC
1.
Elimination of reactive power drawn from power utilities, reduction of electricity
cost also with fast fluctuating loads; duty cycles of a few seconds are possible
2.
Fast switching without delay time for discharging (< 20 ms)
3.
Cost saving: investment reduction for new equipment (distribution equipment,
transformer, cable cross section etc.), due to cutting-off of peak loads
4.
Stabilizing of grid voltage, means avoiding of voltage drop, e.g. welding therefore improvement of welding process in terms of quality but also in time
5.
Avoiding of flickering
6.
Smooth switching, transients
power quality will be improved
7.
Increase of life time of a capacitor bank due to contact less switching and
smooth switching (switching device as well as capacitors)
EPCOS AG FK PM PFC (RM)
free
(voltage
DYNAMIC PFC
as
well
as
30.04.2003
current),
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N
E
T
Z
L
A
S
T
EchtzeitBlindleistungsregler
TSM – C
1 ... n
Real time Power factor controller
DynamiC 

Reaction-time: about 20 ms
EPCOS AG FK PM PFC (RM)
DYNAMIC PFC
30.04.2003
Page: 5
Features expected of dynamic PFC?
Transient-free switching
Power factor correction with high switching frequency
Minimal reaction-time
Free of wear out
Enhancement of power quality
Flicker-compensation
EPCOS AG FK PM PFC (RM)
DYNAMIC PFC
30.04.2003
Page: 6
TSM-C Thyristor switch
TSM – C for Active (dynamic, real time) PFC
Fast Thyristor switch for capacitive loads up to 50 kvar.
The TSM-C is a fast electronically controlled, selfobserving thyristor switch for capacitive loads up to
50 kvar, which is capable to switch PFC capacitors
within a few milliseconds as often as required.
EPCOS AG FK PM PFC (RM)
DYNAMIC PFC
30.04.2003
Page: 7
TSM-C Thyristor switch
The TSM-C observes permanently:
- voltage (availability & value)
- phase sequence
- capacitor rated current
- temperature of the power switches
When voltage problems occur, the TSM turns-off.
By supervising of the capacitor-current it is possible to identify dangerous operating
conditions, such as harmonic distortion. High current harmonics may cause the destruction
of the connected PFC capacitor. Over currents are measured by an integrated measuring
system. The module turns-off as long as the overload exists.
The highly advanced measuring circuit for self-observing of the thyristor switch protects the
capacitor and the application as well.
The alarm-signal of the temperature trigger switches-off the corresponding capacitor
branch. After dis-connection the thyristor switch will cool down again, if the temperature
decreases below the preset threshold value, the module will reconnect.
EPCOS AG FK PM PFC (RM)
DYNAMIC PFC
30.04.2003
Page: 8
TSM-C Features:
1.
Easy installation: it can be used identically as a contactor and can be put into
operation even with a standard controller (our recommendation is the BR6000-T
controller with transistor output). All the intelligence needed is offered with the
thyristor module itself.
2.
The TSM-C is a fast electronically controlled, self-observing power switch for
capacitive loads up to 50 kvar
3.
Due to “full wave switching” no harmonics generated by TSM-C
4.
Very fast reaction time: < 7 milliseconds only
5.
Permanent self-controlling of:
- voltage parameter
- capacitor-current
- temperature of the thyristor-switch.
6.
Cascading output
7.
Alarm output per module
8.
Compact and modern design
EPCOS AG FK PM PFC (RM)
DYNAMIC PFC
30.04.2003
Page: 9
TSM-C high end design :
1.
Modern design with compact casing
2.
2 high voltage thyristor modules
3.
2 large heat sinks
4.
2 current transformer
5.
Intelligent control board for zero crossing switching
6.
Firing board for thyristor firing
7.
PCB for self diagnostic of all important electrical and thermal parameters
8.
Front plate with operation and error message display
EPCOS AG FK PM PFC (RM)
DYNAMIC PFC
30.04.2003
Page: 10
Comparison of inrush current
Left hand graph shows a inrush current of
157 times nominal current caused by PFC
capacitor parallel switching with standard
motor contactor.
EPCOS AG FK PM PFC (RM)
The thyristor connects the capacitor with almost Zero
delay time. As soon as the control signal is applied to
the thyristor, it starts carrying the capacitor current,
means ULTRA FAST switching. At the same time this
graph shows that the current is starting from ZERO (Xaxis), up to its maximum value without any inrush
current effect.
>> no inrush current <<
DYNAMIC PFC
30.04.2003
Page: 11
Switching at ZERO crossing
EPCOS AG FK PM PFC (RM)
DYNAMIC PFC
30.04.2003
Page: 12
Reduction of apparent power saves investments
EPCOS AG FK PM PFC (RM)
DYNAMIC PFC
30.04.2003
Page: 13
TOWER AUTOMOTIVE – PRESS AND WELDING CENTER
EPCOS AG FK PM PFC (RM)
DYNAMIC PFC
30.04.2003
Page: 14
Real case in Germany, a supplier for Volkswagen (pressing of sheet steel)
• Huge presses for forming the metal sheet steels, up to 7500 tones
• Huge load fluctuation
• Due to further adding of a new press of 7500 tons the electrical system was over loaded
• The factory owner was very much convinced that this system pays off very fast even if it is much
more expensive than a conventional capacitor bank. But this can not be compared anyhow!
• Reasons for him:
Fast compensation and eliminating reactive power drawn from energy supplier
Improvement of power quality (e.g. flickering)
2500 Ampere bus bar still OK, means a new investment for a new 3500 A bus system through the
factory and a new supply transformer (+ building) can be avoided
• The factory owner was very much convinced and ensured me that he will definitely go for
Real Time PFC with the next extensions of the factory.
EPCOS AG FK PM PFC (RM)
DYNAMIC PFC
30.04.2003
Page: 15
Conventional and dynamic PFC, mixed
operation (hybrid mode)
Usually for power factor controllers, only conventional PFC via
contactors or dynamical compensation via thyristor switches is
possible. A unique feature of BR6000 is the so called „mixed
operation“, means the basic load is compensated with
contactors, but only the fast changing load peaks are
compensated via thyristors. Therefore, not the complete
system needs to be equipped with the very costly
thyristors, but only a few stages!
EPCOS AG FK PM PFC (RM)
DYNAMIC PFC
30.04.2003
Page: 16
Conventional (relay output) and dynamic
PFC (transistor output)
EPCOS AG FK PM PFC (RM)
DYNAMIC PFC
30.04.2003
Page: 17
Conventional (relay output) and dynamic
PFC (transistor output)
EPCOS AG FK PM PFC (RM)
DYNAMIC PFC
30.04.2003
Page: 18
Attention:
Don’t touch live parts in the PFC equip., even disconnected caps are loaded up to 1500 VDC!!
Warning signs in the equipment required!!
Wait 10 minutes after the main switch is turned off – until the voltage in the system is down to
an uncritical value.
In non-detuned systems (400V grid) you need capacitors with a voltage of 440 V !
In de-tuned systems (400 V grid) you need capacitors with a voltage of 525 V !
For discharging the capacitors special high-voltage resistors type EW22 are required.
Standard resistors can not be used!
In dynamical PFC systems discharge reactors cannot be used!
(this would cause a shortcut of the high-voltage DC )
In PFC systems without filter circuit reactors current limiting reactors are required
( e.g. BD-100 ) for the TSM.
EPCOS AG FK PM PFC (RM)
DYNAMIC PFC
30.04.2003
Page: 19
Example of RT PFC module: to compact, to hot!!!
EPCOS AG FK PM PFC (RM)
DYNAMIC PFC
30.04.2003
Page: 20
Example of REAL TIME PFC panel
EPCOS AG FK PM PFC (RM)
DYNAMIC PFC
30.04.2003
Page: 21
Accessories for REAL TIME PFC
1. Discharge resistors: EW-22
- Discharge resistors for PFC capacitor
- For usage with TSM-C thyristor module
(Discharge reactors are not allowed!)
Power:
Voltage:
100 W
1200 V
2. Inrush current limiting coil: BD 100
- Current limiting coil for reduction of inrush currents
- For usage with TSM-C thyristor module
- Max. current 100 A
3. Over current protection: NH-SF-80 / NH-SF-160
- Electronic super-fast fuses
- For protection of the thyristor module and PFC modules
EPCOS AG FK PM PFC (RM)
DYNAMIC PFC
30.04.2003
Page: 22
Dynamic PFC Module: TSM-AT
Features:
Real 3-phase-switching (single phase capacitors)
Output up to 100 kvar at 690 V
Usage for PFC-systems with and without reactors
Connected load (output) programmable
Easy programming for the individual application
Via multi-lingual plain language display
Indication of all relevant parameters of the grid
Alarm output and error message storage
EPCOS AG FK PM PFC (RM)
DYNAMIC PFC
30.04.2003
Page: 23
Dynamic PFC Module: TSM-AT
EPCOS AG FK PM PFC (RM)
DYNAMIC PFC
30.04.2003
Page: 24
Dynamic PFC Module: TSM-AT
EPCOS AG FK PM PFC (RM)
DYNAMIC PFC
30.04.2003
Page: 25