CONSTRUCTION OF GENERATOR CAPABILITY A CURVES
construction of generator ca atcs ca atcs capability curves construction of generator ca atcs ca atcs capability curves
Introduction • The armature leakage reactance is usually approximated by the Potier reactance. • The values of the Potier reactance is greater than the leakage reactance (up (p to 50% of the leakage reactance, which is confirmed by the results of our research). • The importance of Potier reactance determination is reflected in: • Leakage reactance is nearly independent on saturation (X l = Const.). • Saturation curve of the generator under load conditions is assumed to be the same as the open-circuit saturation curve. • Any error introduced by the use of the open-circuit saturation curve is compensated by using the Potier reactance (X p >X l ). • For turbogenerator, the air gap is assumed to be uniform so that • the direct-axis reactance is equal to the quadrature axis reactance, X d = X q • the unsaturated direct-axis reactance is calculated by equation X du = X a + X l . • In numerous researches it is shown that Potier reactance values depend on terminal voltage.
THE POTIER REACTANCE DEPENDENCE ON (REACTIVE) LOADS • Based on research results, author came to the following conclusion: • The Potier reactance mostly depends on reactive currents (i aQ = i an·sinφ), • It is verified by: • general qualitative analysis, and • experiment, for loads about rated active and reactive power, for generator GTHW 360 (360 MW) • Standard procedure for determining Potier reactance is based on reactive load test with voltage and current which differ from their rated values by not more then ± 0.15 per unit. • Author proposes that Potier reactance should be determined from reactive load test for three values of armature current: • I a1 =I a,max >I aN·sinφ N (i.e. Q G1 =Q Gmax >Q GN ), corresponding to I f =I f,N and U G1 = U G at Q G1 =Q Gmax >Q GN (point C 1 , Figure 1); • I a2 =I aN ·sinφ N (i.e. Q G2 =Q GN )andU U G2 =U G at Q 2 =Q N (point C 3 , Figure 1); • I a3 =(I a1 +I a2 )/2, i.e. Q G3 =(Q Gmax Gmax +Q GN GN )/2 and U G3 =U G at Q G3 point C 2 , Figure 1).
- Page 1 and 2: CONSTRUCTION OF GENERATOR CAPABILIT
- Page 3 and 4: Introduction • Capability curves,
- Page 5 and 6: BASIC PRINCIPLES FOR THE DESIGN OF
- Page 7 and 8: BASIC PRINCIPLES FOR THE DESIGN OF
- Page 9 and 10: DETERMINATION OF GENERATORS POTIER
- Page 11 and 12: CONSTRUCTION OF GENERATOR CAPABILIT
- Page 13 and 14: Conclusion • It has been establis
- Page 15: Abstract The author came to the fol
- Page 19 and 20: DETERMINATION OF POTIER REACTANCE (
- Page 21 and 22: Potier reactance dependence on the
- Page 23 and 24: Potier reactance dependence on the
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THE POTIER REACTANCE<br />
DEPENDENCE ON (REACTIVE) LOADS<br />
• Based on research results, author came to the following conclusion:<br />
• The Potier reactance mostly depends on reactive currents (i aQ = i an·sinφ),<br />
• It is verified by:<br />
• general qualitative analysis, and<br />
• experiment, for loads about rated active and reactive power, for generator<br />
GTHW 360 (360 MW)<br />
• Standard procedure for determining Potier reactance is based on reactive load<br />
test with voltage and current which differ from their rated values by not more<br />
then ± 0.15 per unit.<br />
• Author proposes that Potier reactance should be determined from reactive load<br />
test for three values of armature current:<br />
• I a1 =I a,max >I aN·sinφ<br />
N (i.e. Q G1 =Q Gmax >Q GN ), corresponding to I f =I f,N and U G1 = U G at<br />
Q G1 =Q Gmax >Q GN (point C 1 , Figure 1);<br />
• I a2 =I aN ·sinφ<br />
N (i.e. Q G2 =Q GN )andU<br />
U G2 =U G at Q 2 =Q N (point C 3 , Figure 1);<br />
• I a3 =(I a1 +I a2 )/2, i.e. Q G3 =(Q Gmax<br />
Gmax +Q GN<br />
GN )/2 and U G3 =U G at Q G3 point C 2 , Figure 1).
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