APPLICATIONS OF SVS

APPLICATIONS OF SVS:

1. A static var system provides fast,smooth and stepless variation of compensations

of reactive power injected in the line. Thus it ensure an accurate voltage control of

buses over a wide range of loads.

2. The static var systems are used to control the reactive power demand of large fluctuating

loads such as rolling mills, are frunances etc.

3. If a large load is switched off, the voltage at the loading end of the line increases

( Farranti effect).The static var system provides a fast change in the reactive power

compensation to regulate the voltage.

4. In HDVC converter station, the provision of the static var system mainly helps to

have fast control of reactive power flow. Thus voltage fluctuations are controlled

and the problem of instability is overcome.

ADVANTAGES OF SVS

ADVANTAGES OF SVS:

1. Power transfer capability of the lines is increased.

2. Transient stability of the system is improved.

3. The dynamic stability is also improved.

4. It is possible to damp subsynchronous reactance freq oscillations.

5. Steady-state and temporary over voltages can be controlled.

6. Load power factor is improving consequently losses are reduced and the system efficiency is improved.

7. The dynamic response of SVS is fast.

8. The maintenance is easy.

STATIC VAR SYSTEMS (SVS)

STATIC VAR SYSTEMS (SVS) :

In EHV transmission practice, when the voltage cut at a bus falls below the reference value , capacitive vars to be injected.

When the bus voltage becomes higher than reference value, inductive vars are supplied

to lower the bus voltage.

In conventional methods of shunt compensation, shunt reactors are connected during

low loads and shunt capacitors are connected during heavy loads or low lagging power factor

loads.

In a static var system , thyristor are used as switching devices instead. CB thyristor switching is faster than mechanical switching and also it is possible to have transient-free

operation by controlling the instant of switching.

The advent of high speed, high current switching mode possible by thyristor has introduced a new concept is providing reactive compensation for optimum EHV/UHV system

performance.

The static var compensators (SVC) used shunt reactor and shunt capacitor combinations

with high current thyristor obtaining fast and accurate control of power flow. The

Static var compensation (SVC) is also known as Static Var System (SVS).