3582374819

STANI MEMORIAŁ COLLEGE OF ENGINEERING & TECHNOLOGY

POWER SYSTEM DESIGN LAB EXPERIMENT NO. 5

Aim:- Sending end and receiving end power circle diagrams.

A p pa rat us Requirements: - Transmission lines, Load data. generation data.

Theory: - The circle diagram is the graphical representation of the performance of the electrical machinę and transmission linę drawn in terms of the locus of the machine's input voltage and current. The circle diagram can be drawn for altemators. synchronous motors. transformers. induction motors. The Heyland diagram is an approximate representation of circle diagram applied to induction motors. which assumes that stator input voltage. rotor resistance and rotor reactance are constant and stator resistance and core loss are zero.

Active and reactive powers in a transmission linę depend on the voltage magnitudes and phase angles at the sending and receiving ends as well as linę impedance.

Generally the load is usually expressed in terms of Active Power (watts) and Reactive Power (VARs). Therefore we calculate transmission linę performance equation in terms of Sending end and Receiving end complex power and Voltage.

Complex, active and reactive power flows in this transmission system are defined. respectively. as follows:

Sr = Pr +jQR = V_R I*

„ Vę Vr . -P_R = ——— sm 8 X

„ V_s V„ cos 8 - V»

Qr =—-^L

X