SVG works
SVG is the
latest generation technology dynamic power compensation representative of the
field, its basic principle is to use the turn-off high-power electronic devices
(e.g., IGBT) consisting of self-commutated bridge circuit, through the reactor
in parallel on the grid, The proper adjustment of the amplitude and phase of
the AC side output voltage of the bridge circuit or the direct control of the
AC side current can make the circuit absorb or send out the reactive current
that meets the requirements and realize the purpose of dynamic reactive power
compensation. SVG parallel in the grid, on the one hand effectively solve the
problem of harmonic interference switching parallel capacitor device, on the
other hand, according to the actual requirements of users to suppress or
control harmonics, improve power quality.
SVG's main function:
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SVG applications:
SVG is
widely used in petrochemical, metallurgy, electric power, coal, electrified
railways, wind farms and other industries with or near impact loads and
high-capacity motors, saving energy, increasing grid safety and stability,
Power factor, improve power quality, etc., play an important role.
SVG is
currently the most advanced reactive power compensation device, based on the
voltage source inverter compensation device to achieve a qualitative leap in
reactive power compensation. It no longer uses large-capacity capacitors,
inductive devices, but through the power electronic devices to achieve
high-frequency switching of reactive energy conversion. Technically, SVG has
the following advantages over traditional reactive power compensation devices:
◆ faster response
SVG
regulation speed, the response time of less than 10ms, can be completed within
a very short time from rated capacitive reactive power to rated inductive
reactive power conversion, this unparalleled response speed can be fully
qualified for impact Load compensation.
◆ voltage flicker suppression so stronge
SVG
regulation speed, the response time of less than 10ms, can be completed within
a very short time from rated capacitive reactive power to rated inductive
reactive power conversion, this unparalleled response speed can be fully
qualified for impact Load compensation.
◆ voltage flicker suppression so stronge:
SVC voltage
flicker suppression up to 2: 1, SVG voltage flicker suppression can reach 5: 1,
or even higher. SVC is limited by the speed of response and its ability to
suppress voltage flicker does not increase with the compensation capacity. The
SVG due to fast response speed, increasing device capacity can continue to
improve the ability to suppress voltage flicker.
◆ wider operating range
SVG can
work in the range of rated perceptual to rated capacity, so it is much wider
than the running range of SVC. More importantly, the SVG can output reactive
current similar to the nominal operating conditions when the system voltage is
low.
◆ Compensation function diversification
The company
SVG not only has the purpose of rapid compensation system reactive power, but
also according to the actual needs of users, the load harmonic current and
other power quality issues comprehensive compensation.
◆ low harmonic content
The company
SVG uses carrier phase shift PWM technology and power unit cascade multi-level
technology, its own very low harmonic content.
◆ Small footprint
Since
high-voltage, high-capacity capacitors and reactors are not required as energy
storage components, SVGs typically occupy only 50% of the same capacity SVC.
Device structure:
◆ scope of application
◆ Suitable for low voltage system (380V ~ 1140V) dynamic reactive power
compensation.
◆ If the variability of reactive power is large and the harmonics are not
serious, the SVG compensation device and the parallel capacitor compensation
hybrid application scheme should be adopted.
◆ Reactive power and harmonics vary widely serious system should pure
SVG type compensation device.
◆ small changes in reactive power, but the system of serious harmonics,
should adopt pure SVG device,Or use AP F device to manage harmonics,Compensate
the power factor with shunt capacitor bank.
◆ Selection suggestion
Take the
maximum perceptual compensation capacity of 100Kvar and 200Kvar respectively as
an example, how to combine the parallel capacitor compensation with the active
dynamic compensation device in practical application.
Using ±
50Kvar IGBT inverter and 50Kvar capacitor connected in parallel with the
system, dynamic reactive power from 0 to 100Kvar inductive continuously
adjustable: that reactive power compensation capacity of 100Kva r, of which
100% of the dynamic compensation capacity.
With ±
30Kvar lGBT inverter and 70Kva capacitor connected in parallel to the system,
the dynamic reactive power from the perceptual 40Kvar to 100Kvar perpetual
adjustable: reactive compensation capacity of 100Kvar perceptual, of which 60%
of the dynamic compensation capacity.
SVG primary system diagram
Specifications
and technical parameters
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