The necessary equation to be solved during the load flow analysis using Fast-Decoupled methid is given below:
where B' and B'' are formed using the imaginary part of the bus admittance matrix Ybus, n is the total number of buses in the system, m is the number of voltage regulated buses. The size of matrix B' is
∆P/|Vi|= -B' ∆δ
∆Q/|Vi| = -B'' ∆|Vi|

In FDLF method,
B' corresponds to susceptance of unknown of PQ and PV bus
Order of B' matrix is = (n -1)*(n - 1)
Where n is total no. of buses.
Order of B'' = (n - m - 1)*(n - m - 1)

Insulation Power Factor testing on an oil-filled transformer is not helpful in determining ___

A form of AC testing that applies voltage and measures the leakage/loss current of electrical insulation.
It is a type of insulation testing used to evaluate the integrity of electrical insulation.

If a 415 V, 50 Hz, star-connected, three-phase squirrel-cage induction motor is operated from a 415 V, 70 Hz supply, the torque that the motor can now provide while drawing rated current from the supply

The miniature circuit breaker (MCB) shown in figure is

A given solar cell has the following specifications: Isc = 4 A and Voc = 0.7 V. Consider that 20 identical cells with the above specifications are to be interconnected to create a PV module. What is the open-circuit voltage of the PV module if all the solar cells are connected in a series configuration?

For M no. of series configuration of solar cell,
Open circuit voltage of PV module= M*Voc
= 20*0.7
= 14 V
Short circuit current of PV module = M*Isc
= 20*4
= 80 A

As per ___ guidelines, if the ratio of carbon dioxide (CO₂) and carbon monoxide (CO) in dissolved gas analysis is ___, it is predicted that the condition of paper insulation inside the transformer is poor.

There is one IEC guideline, number is IEC 599,
Statement of guideline is that "If the ratio of carbon dioxide and Carbon monoxide in Dissolve gas analysis test result is more than 11, it is predict that the condition of paper insulation inside the transformer is poor."
For healthy condition this ratio will be between 4 to 11.