i am not able to get graph

H= 2.7

E= 1.05

V=1

g=5000000

p=5000000

f=50

dt=0.05

omega=0

base=g

G=g/base

M=(H*G)/(180*f)

Xs=0.4

Xe=1

pt=1

delta=asin((pt*Xs)/(E*V))

delta_d=delta*180/pi

dd=1

for t=0:0.05:0.5

pe_n=(E*V*sin(delta)/Xe)

pe=1-pe_n

pa=pe/M

if t==0

pa=pa/2

else

pa=pa

end

d_omega=pa*dt

omega=omega+d_omega

d_delta=omega*dt

plot(t,delta_d)

xlabel('in seconds')

ylabel('in \delta(degree')

delta_d=d_delta+delta_d

dd=dd+1

end

Answer 1

[Star Strider]

Try this —

H= 2.7;
E= 1.05;
V=1;
g=5000000;
p=5000000;
f=50;
dt=0.05;
omega=0;
base=g;
G=g/base;
M=(H*G)/(180*f);
Xs=0.4;
Xe=1;
pt=1;
delta=asin((pt*Xs)/(E*V));
delta_d=delta*180/pi;
dd=1;
tv=0:0.05:0.5;

figure
hold on
for k = 1:numel(tv)
    t = tv(k);
    pe_n=(E*V*sin(delta)/Xe);
    pe=1-pe_n;
    pa=pe/M;
    if t==0
        pa=pa/2;
    else
        pa=pa;
    end
   d_omega=pa*dt;
   omega=omega+d_omega;
   d_delta = omega*dt;
   plot(t,delta_d, 'p');
   xlabel('in seconds')
   ylabel('in \delta(degree')
   delta_d=d_delta+delta_d;
   dd=dd+1;
end   
hold off

Plotting individual points in the loop requires plotting with a marker.

.

[Sanjay N]

what is the reason in my program that i am not able to get graph

[Sanjay N]

can you please explain why my program doesnt plot graph and what may be the reason. It will be a great help

thank you

[Star Strider]

Two reasons, actually.

The first is that you need to plot markers, not lines, because plotting lines requires two (x,y) values to plot a line between them. Markers plot points.

The second is that plotting in a loop requires the use of the hold function so that all the markers are plotted on the same axes. Otherwise, without using hold, the older plotted values are eliminated and the newer values plotted over them.

[Walter Roberson]

plot() only draws lines between adjacent pairs of finite coordinates. You are passing in scalar values, so you do not have adjacent pairs of coordinates, so it does not draw any lines.

It does not draw any markers for you in your plot call because markers are off by default.

[Sanjay N]

clc

clear all

E=input('enter emf in pu')

V=input('enter voltage in pu')

f=input('enter frequency')

H=input('enter inertia constant')

g=input('enter generating power in VA')

P=input( 'enter power')

dt=0.05

omega=0

base=g

G=g/base

M=(G*H)/(180*f)

Xs=0.4

Xe=1

Pt=1

delta=asin((Pt*Xs)/(E*V))

delta _d=delta*180/pi

dd=1

for t=0:0.05:0.5

Pe_n=((E*V*sin(delta_d*pi/180))/Xe)

Pe=1-Pe_ n

Pa=Pe/M

if (t==0)

Pa=Pa/2

else

Pa=Pa

end

d_omega=Pa*dt

omega=d_omega+omega

d_delta=omega*dt

x(dd)=t

y(dd)=delta_d

plot(x,y)

delta_d=d_delta+delta_d

dd=dd+1

end

in these program you will get line graph why is that

[Sanjay N]

E=input('enter emf in pu')=1.05

V=input('enter voltage in pu')=1

f=input('enter frequency')=50

H=input('enter inertia constant')=2.7

g=input('enter generating power in VA')=5000000

P=input( 'enter power')=5000000

[Star Strider]

‘in these program you will get line graph why is that’

Because:

x(dd)=t
y(dd)=delta_d

are saved as vectors.

.

[Sanjay N]

i am sorry for annoying you please check above program and tell me why i am getting line graph

[Sanjay N]

got it scalars have no direction and vector has direction

[Star Strider]

Not annoying at all!

Just short time intervals. I cannot immediately respond.