52217-mt----power System Reliability

NR

Code No: 52217/MT

M.Tech. – II Semester Regular Examinations, September, 2008 Power System Reliability (Electrical Power Systems) Time: 3hours

Max. Marks:60 Answer any FIVE questions All questions carry equal marks ---

1.a) b)

Explain expected loss of energy method. A generation system consists of 2 units of 30MW capacity each with λ =0.4/year and µ =0.96/yr. The daily peak loads of worked over an year are found to be as follows: Daily peak load (MW)

% time the peak has occurred

50 40 30 20

30% 40% 20% 10%

Calculate the expected loss of energy. 2.

A Generating station has 3 generators rated for 10 MW and a fourth one rated for 20 MW. The failure and repair rates of each of the 4 units are 0.35/year and 9.65/year respectively. Obtain simplified state space model combining equal capacity states and obtain the following transmission rate: (i) From 40MW to 20 MW state (ii) From 10 MW to 30 MW state.

3.a) Explain a method for computing the probability of capacity deficiency in a generation system. b) A power plant has 5 units of capacity 50 MW each with a listed outage rate of 0.01. Obtain the capacity outage probability table. The system load model is given below Contd…2.,

Code No: 52217/MT

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4.

A generating system consists of two units A and B of 20Mw and 30Mw capacities with forced outage rates of 0.1 and 0.05 respectively. If the mean repair time of either unit is 30 days, calculate a) Probability and frequency of occurrence of exact capacity state of 30 Mw b) Probability and frequency of failure of the system if the load is steady at 40Mw.

5.a)

Describe with state space diagram, the Markov model of a single transmission line under two weather environments. Explain with state space diagram how the pf and f of system consisting of two independent transmission lines under two weather environment.

b)

6.a) b)

Explain how load is represented in a 2 –state model. Develop the mathematical model for the same for determining the probability of load available. Explain how combined generation-load model is developed and hence develop the expressions for cumulative probability and cumulative frequency of various combined capacity states.

7.a)

Consider the following two systems System A: 6 x50 MW – FOR = 4% Peak load: 240 MW System B: 6x100MW – FOR=6% Peak load=480MW The two systems are interconnected by a 50MW tie line. Calculate the loss of load expectation in each of the system on a one – day basis for the above data.

8.a)

Describe the 3 state modes of a transmission line section subject to switching Explain what is meant by active events and explain how the probability of these events can be evaluated?

b)

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