Most of the industrial installations with loads require compensations to be able to correct or balance these existent fluctuations and uses Static Var Compensators.
As was mentioned in 1.1 one of the systems, which allows to compensate the power, is between the use of Static Var Compensators.
These are being used increasingly due to the technical advantages, which they offer between transmission systems. Advantages such as: [Ref.12, pp.2]
- Compensation for the change in reactive power produced by a change in the transmitted power.
- In the event of line switching caused by faults or changing network configuration, there is compensation for a change in reactive power.
- Reduction and limitation of power frequency over voltages produced by the load.
- Improvement of the system in a long distance transmission.
Figure 1.4 shows a simple schematic of a Static Var Compensators. It is comprised of the following features:
- Transformer
- Thyristor Controlled Reactor (TCR)
- Thyristor Switched Capacitor (TSC)
- Capacitors Bank
The transformer is not part of the of the Static Var Copensators.
Thyristor Controlled Reactor is part of the Static Var Copensators and is based on a couple of thyristors and impedance in series as shown in Figure 1.4. TCR will produce the sufficient inductive reactance to compensate the network.
Transmission capacitive reactance is part of the Static Var Copensators, as the delay angle (
) increases, less vars from the network are going to be absorbed and the current through the TCR can be varied triggering the thyristors at different angles. As the delay angle (
) is higher as the load phase angle (
) then the fundamental component of the thyristors current is reduced. It is shown in detail in chapter 4 section 4.1.2.
Figure 1.4
Thyristor Switched capacitors are part of the Static Var Copensators and are also based on a couple of thyristors, which will turn on and turn off the capacitor in the shortest time possible. The TSC is switched on and off, thus providing discreet step variation of the Static Var Compensator (SVC) capacitive current. In this way, transients are minimized.
The main advantage of the thyristor switched capacitors is that losses can be minimized when they are used in combination with Thyristor Controlled Reactor.
We have seen a quick introduction to the Static Var Compensators and we hope this will be sueful to understand the next concepts.
http://school-e.co.uk -Static Var Compensators-
You can correct or balance existent fluctuations with Static Var Compensators (SVC info)