A transmission line rated at 1000 MVA has a power flow of 990 MW and 100 MVAR. Is the transmission line overloaded?

Prepare for the NERC System Operator Exam. Leverage flashcards and multiple choice questions with explanations. Get ready for your test!

To determine whether the transmission line is overloaded, it's important to consider both the active power (MW) and reactive power (MVAR) flow in relation to the line's rating. The line is rated at 1000 MVA, which signifies the maximum apparent power (S) it can handle.

To evaluate the current operating conditions, you can calculate the total apparent power using the formula:

[ S = \sqrt{P^2 + Q^2} ]

where P is the real (active) power in MW and Q is the reactive power in MVAR.

In this case, the values given are:

  • P = 990 MW

  • Q = 100 MVAR

Now, substituting these values into the formula:

[ S = \sqrt{(990)^2 + (100)^2} ]

[ S = \sqrt{980100 + 10000} ]

[ S = \sqrt{990100} ]

[ S \approx 995.05 , MVA ]

Since the calculated apparent power (approximately 995.05 MVA) is below the line's rated capacity of 1000 MVA, the transmission line is not overloaded under these operating conditions.

The assertion that

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