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svc
Transformer
A step-down transformer is usually placed between the
AC system bus-bar and the low voltage bus-bar to
which the thyristor valves are connected. Once the SVC
capacity is determined, the best way to design the
valve is to use the thyristor current capability at its
maximum. Then the minimum necessary AC voltage is
derived to obtain the given capacity. The AC voltage
across the thyristor valve determines the number of
thyristors in the valve and consequently the valve cost.
The step-down transformer adjusts the AC voltage for
the minimum system cost. The transformer increases
the thyristor valve efficiency.
TCR Reactor
The TCR reactor generates inductive reactive power of
the SVC. Air core reactors are most commonly applied.
The inductance value of the reactors is custom
designed for each system in order to satisfy the
specified reactive power output.
AC Filter Bank
AC filter banks provide capacitive reactive power and
absorb the harmonic currents generated by the TCR.
The AC filter banks are carefully designed considering
the harmonics environment in the AC system. Usually,
oil filled
capacitors with fuse and air core reactors are applied.
Switchgear
Switchgear is necessary to connect or disconnect the
SVC to or from the AC system. Toshiba is one of the
major suppliers of both gas and air insulated
switchgear.
Voltage Control
275kV, 230MA SVC
-80MVA (inductive) to
+150MVA (capacitive)
Australia (QLD)
TCR + FC
Power Oscillation Damping
275kV, 300MA SVC
-140MVA (inductive) to
+160MVA (capacitive)
Australia (SA)
TCR + TSC
Over-voltage Suppression
400kV, 580MA SVC
-580MVA 500ms (inductive)
TCR
Australia
Voltage Stabilization
500kV, 100MA SVC
-20MVA (inductive) to
+80MVA (capacitive)
Japan (Tokyo)
TCR + FC
STATCOM
500kV, 50MA
Japan (Nagoya)
Mobile SVC
-40MVA (inductive) SVC
Japan (Osaka)
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Based on vast experience in STATCOM using GTO devices, Toshiba has developed a more advanced
M
semiconductor PG
adevice, the Injection Enhanced Gate Transistor (IEGT).
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The IEGT has high
power ratings comparable to the GTO and can be operated at high speed comparable to the
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Insulated Gate esar Bipolar Transistor (IGBT).
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The IEGT is theIM
T
Is voltage driven device and needs a small amount of power for triggering. The number of gate
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m the size of snubber circuits are dramatically reduced in comparison with the GTO. The IEGT
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circuit parts and
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valve makes SVC
more compact and cost-effective..
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Features;
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Low losses
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Low gate m
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Fast switching
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