A synchronous generator of reactance 1.25 pu is connected to an infinite bus bar system of V =1 pu through a line and transformers of a total reactance of 0.5 pu. The generator’s inertia constant is H = 5 s and EMF is 2.5 pu, and it operates at a load angle of 47°. Find the expression of the

Question

A synchronous generator of reactance 1.25 pu is connected to an infinite bus bar system of V =1 pu through a line and transformers of a total reactance of 0.5 pu. The generator’s inertia constant is H = 5 s and EMF is 2.5 pu, and it operates at a load angle of 47°. Find the expression of the oscillations set up when the generator is subject to a sudden change of + 0.5 % of its speed.

Accepted Answer

The transmitted power of the generator is

[latex]P_e=\frac{EV}{X}\sin\delta =\frac{2.5\cdot 1}{1.25+0.5}\sin 47°=1.04 [/latex] pu,

and the synchronized power is

[latex]P_s=\frac{2.5·1}{1.25+0.5}\cos 47°=0.974 [/latex] pu.

Therefore, the angular frequency of oscillation is

[latex]\omega_n =\sqrt{0.974·(\pi·60)/5}=6.06 rad/s, [/latex]

or

[latex]f_n = 6.06/2\pi = 0.96 Hz. [/latex]

The amplitude of oscillation will be

[latex]A=\frac{\omega _{\Delta }}{\omega _n}=\frac{0.005·377}{6.06} =0.31 rad. [/latex]

Thus

[latex]\delta_{\Delta }(t)=0.31 \sin 6.06t rad. [/latex]

Question 8.2: A synchronous generator of reactance 1.25 pu is connected to...

Related Answered Questions

Examine the voltage stability of a non-static load supplied from a 275 kV infinite bus bar through a line of reactance 50 Ω per phase. The load consists of a constant active power of 200 MW and 200 MVAr rating reactive power, which is related to the voltage by the equation (in pu) ...

Verified Answer:

Apply the equal-area criterion to the system of Example 8.3. ...

Verified Answer:

Assume that, at the sending-end of one of the transmission lines in the system shown in Fig. 8.7, a three-phase fault occurs. Develop and solve the swing equation of the system, if the fault reactance is 0.07 pu. The inertia constant of the generator is H = 0.5 s and the frequency f = 60 Hz. ...

Verified Answer:

A synchronous generator having a local load, represented by constant impedance, is connected to an infinite bus through a transformer and a double circuit transmission line. The direct axis generator synchronous reactance is 1.2 pu, the load impedance is Zload = 2 ∠ 36° pu and the rest of the ...

Verified Answer: