说明：  E=input( enter the generator voltage: ) V=input( enter the infinite bus voltage: ) Gx=input( enter the reactance of generator: ) L1x=input( enter the line reactance: ) L2x=input( enter the line reactance: ) L3x=input( enter the line reactance: ) L4x=input( enter the line reactance: ) Pi=input( enter the input power: ) X1=Gx+L1x+((L2x*L3x)/(L2x+L3x))+L4x Pm1=E*V/X1 DO=asin(Pi/Pm1) A=((L2x*L3x)/(2*(L2x+L3x))) C=A B=((L3x/2)^2)/(L2x+L3x) X2=(Gx+L1x+A)+(L4x+A)+(Gx+L1x+A)*(A+L4x)/B Pm2=(E*V)/X2 X3=Gx+L1x+L2x+L4x Pm3=(E*V)/X3 DC=input( enter the fault clearing angle: ) Dm=(3.14-asin(Pi/Pm3)) a1=quad( sin ,DO,DC) A1=(Pi*(DC-DO)-Pm2*a1) a2=quad( sin ,DC,Dm) A2=Pm3*a2-Pi*(Dm-DC) if(A2>=A1) disp( the system is stable ) else disp( the system is unstable ) end Dcc=acos((Pi*(Dm-DO)-Pm2*(cos(DO))+Pm3*(cos(Dm)))/(Pm3-Pm2)) disp( critical clearing angle: ) Dcc