Mocking up of Hydro Power Plant to Understand Load Frequency Control

Abstract

It is possible to subdivide automatic generation control into fast (primary) and slow (secondary) control modes. The loop dynamics immediately after the load disturbance starts will be determined by AGC's quick primary mode. This fast primary mode of AGC is also known as “Uncontrolled mode” since the speed changer position is unchanged The secondary control acting through the velocity changer and initiated by the appropriate controller is AGC's slow secondary or "Controlled modes." AGC's overall performance in any power system depends on both primary and secondary control loops being properly configured. Therefore AGC's overall performance in any power system depends on the proper design of both the primary control loop (selection of R) and the secondary control loop (selection of additional controller gain). In large power systems, the equilibrium may be obtained inherently by themselves at a point when the new load is compensated by the reduction in power taken by old load plus the power corresponding to kinetic energy extracted from the system. Obviously this equilibrium is obtained at the cost of a reduction in frequency. This equilibrium is self managed by the system and it does not require any governor action. The frequency decline under such a condition is quite large.

Keywords: Hydro, impulse turbine, reaction turbine, runner blades, rotor, PID controller, speed droop, dashpot