Correct Answer - Option 1 : The area is not generating enough power to send the desired amount out of the area
Explanation:
Area control error (ACE) that is defined as
ACE = (Ptie – Psch) + BfΔf = ΔPtie + Bf Δf
Where Ptie and Psch are tie-line power and scheduled power through tie-line respectively and the constant Bf is called the frequency bias constant.
A negative ACE means that the area is not generating enough power to send the desired amount of the area. There is a deficiency in net power output.
Note:
- Without frequency bias, the indicated deficiency would be less because there would be no positive offset added when actual frequency is less than scheduled frequency and the ACE would be less.
- The area would produce sufficient generation to supply its own load and the prearranged interchange but would not provide the additional output to assist neighbouring interconnected area to raise the frequency.