Circle Diagram

This presentation is based on the subject electric power system.Circle diagram of transmission line.In this presentation two topics covered about the circle diagram of transmission line.It is about the medium and long transmission line circle diagram.Receiving-end circle diagram and sending-end circle diagram of the transmission line.This presentation help you to the improve knowledge about the transmission line circle diagram.

1. Gujarat Power Engineering and Research Institute   B.E. SEM. VI (ELECTRICAL). PRESENTED BY : HARSH SONI

2. Circle Diagram

3. Circle Diagram Receiving-end Circle Diagram Sending-end Circle Diagram

4. It has been shown above that-the flow of active and reactive power over a Transmission line can be handled computationally. It will now be shown that the Locus of complex sending- and receiving-end power is a circle. Since circles are convenient to draw, the circle diagrams are a useful aid to visualize the load flow problem over a single transmission. Receiving-end circle diagram

5. The expressions for complex number receiving-and sending-end powers are Reproduced below from above Equations. …(1) …(2)

6. As per the above equations, and are each composed of two phasor components-one a constant phasor and the other a phasor of fixed magnitude but variable angle. The loci for Sr and Ss would therefore be circles drawn from the tip of constant phasors as centres It follows from Eq. ( 1 ) that the centre of receiving-end circle is located at the tip of the phasor.

7. Horizontal coordinate of the centre The radius of the receiving-end circle is Vertical coordinate of the centre

8. Fig.1 Receiving-end circle diagram

9. As per fig.1 the operating point ‘M’ indicates the receiving end values of , and . For constant the centre remains fixed. For varying and constant centre of circles move along the line

10. In polar coordinates Similarly for Eq. (2) the centre of sending-end circle is located at the of the phasor Sending-end circle diagram

11. Horizontal coordinate of the centre Vertical coordinate of the centre The radius of the sending-end circle is

12. Fig.2 Sending-end circle diagram

13. The operating point N is located by measuring the torque angle in the direction indicated from the reference line. For constant the centre remains fixed. For varying and constant centre of circles move along the line

14. Thank You