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Balancing And Frequency Control

 

Balancing And Frequency Control

Frequency is maintained in an interconnection as long there is a balance between power generation and load demand (plus losses).

Balancing and Frequency Control
Balancing and Frequency Control

To understand how Interconnection frequency is actually controlled, it helps to visualize a traditional water utility.

If a municipality operates its own water system, it would need sufficient pumps (generation) to maintain water level in a storage tank (frequency) to serve its customers.

If demand exceeds supply, the water level would drop. Level (frequency) is the primary parameter to control in an independent system.

The frequency regulation/control may be manual or automatic, but in a large interconnected power system, manual regulation is not feasible.

The important control loops in interconnected power system are:

  1. Load Frequency control
  2. Automatic Voltage control
Balancing and Frequency Control
schematic diagram of load frequency and excitation voltage regulators

Fig. gives the schematic diagram of load frequency and excitation voltage regulators of a turbo generator.

The controller are set for a particular operating condition and they take care of small changes in load demand without frequency and voltage exceeding the prescribe limit.

If the change in load demand becomes large, the controller must be reset either manually or automatically.

Necessity Of Maintaining Frequency Constant :

1.All the AC motors require constant frequency as to maintain constant speed.

2.In continuous process industry, it affects the operation of the process itself.

3.For the synchronous operation of various units in the power system network, it is necessary to maintain frequency constant. If the normal frequency is 50 Hz and the system frequency falls below 47.5 Hz or goes up above 52.5 Hz then the blades of the turbine are likely to get damaged so as to prevent the stalling of the generator.

4.Frequency affects the amount of power transmitted through interconnected lines.

5.Electrical clocks will lose or gain time if they are driven by synchronous motors and the accuracy of the clocks depend on frequency and also the integral of this frequency error is loss or gain of time by electric clocks.


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