QUESTIONS FROM PREVIOUS QUESTION PAPERS

1. 1. Briefly explain the control area concept and control area error
2. 1. Obtain the dynamic response of load frequency control of an isolated power system for first order approximation.
   2. Obtain the dynamic response of load frequency controller with and without integral control action.
3. 1. Explain the necessity of maintaining a constant frequency in power system operation.
   2. Two generators rated 200 MW and 400 MW are operating in parallel. The drop characteristics of their governors are 4 percent and 5 percent respectively from no load to full load. Assuming that the generators are operating at 50 Hz at no load, how would a load of 600 MW be shared between them? What will be the system frequency at this load? Assume free governor operation. Repeat the problem if both the governors have a drop of 4.
4. A control area has a total rated capacity of 10,000MW. The regulation R for all the units in the area is 2Hz/p.u MW. A 1 percent change in frequency causes a 1 percentage change in load. If the system operates at half of the rated capacity and the load increases by 2 percent,
   1. Find the static frequency drop.
   2. If the speed governor loop were open, what would be the frequency drop? Derive the formula used.
5. Draw a block diagram representation of load frequency control for a single area system.
6. 1. Obtain the dynamic response of a load frequency controller of an isolated power system at first order approximation.
   2. Obtain the dynamic response of load frequency controller with and without integral control action.
7. 1. Explain the concept of “control area” in the load frequency control of a power system.
   2. Show how the steady state error of frequency in a typical load frequency control of a power system is reduced to zero.