FAKULTI TEKNOLOGI KEJURUTERAAN PLT 304 ELECTRICAL POWER SYSTEM

FAKULTI TEKNOLOGI KEJURUTERAAN PLT 304 ELECTRICAL POWER SYSTEM CHAPTER 2: BASIC PRINCIPLE OF POWER SYSTEM (SINGLE PHASE AC CIRCUITS) ILMU. KEIKHLASAN. KECEMERLANGAN

FAKULTI TEKNOLOGI KEJURUTERAAN Instantaneous Power in Single Phase AC Circuits • Power is the rate of change of energy with respect to time. • The unit is Watt, joule per second • The load voltage is: • This chapter is to investigate the instantaneous power absorbed by: • Purely resistive • Purely inductive • Purely capacitive • General RLC loads • This chapter also introduce the concepts of real power, power factor and reactive power and apparent power ILMU. KEIKHLASAN. KECEMERLANGAN

FAKULTI TEKNOLOGI KEJURUTERAAN Purely Resistive Load ILMU. KEIKHLASAN. KECEMERLANGAN

FAKULTI TEKNOLOGI KEJURUTERAAN Purely Inductive Load ILMU. KEIKHLASAN. KECEMERLANGAN

FAKULTI TEKNOLOGI KEJURUTERAAN Purely Capacitive Load ILMU. KEIKHLASAN. KECEMERLANGAN

FAKULTI TEKNOLOGI KEJURUTERAAN General RLC Load ILMU. KEIKHLASAN. KECEMERLANGAN

FAKULTI TEKNOLOGI KEJURUTERAAN Real Power ILMU. KEIKHLASAN. KECEMERLANGAN

FAKULTI TEKNOLOGI KEJURUTERAAN CIVIL ILMU. KEIKHLASAN. KECEMERLANGAN

FAKULTI TEKNOLOGI KEJURUTERAAN Reactive power Apparent power ILMU. KEIKHLASAN. KECEMERLANGAN

FAKULTI TEKNOLOGI KEJURUTERAAN Example 2. 1 ILMU. KEIKHLASAN. KECEMERLANGAN

FAKULTI TEKNOLOGI KEJURUTERAAN Power Triangle ILMU. KEIKHLASAN. KECEMERLANGAN

FAKULTI TEKNOLOGI KEJURUTERAAN Complex Power • Real power, P – RMS based-thermally equivalent to DC power – real or active power in AC circuit is the power that does useful work in the circuit. • Reactive power, Q – Oscillating power into and out of the load because of its reactive element (L or C). – Positive value for inductive load (lagging pf) – Reactive power flows in an AC circuit but does not do any useful work. • Complex power, S – Apparent power is the total power in an AC circuit. ILMU. KEIKHLASAN. KECEMERLANGAN

FAKULTI TEKNOLOGI KEJURUTERAAN Power Factor ILMU. KEIKHLASAN. KECEMERLANGAN

FAKULTI TEKNOLOGI KEJURUTERAAN Conservation of Power l At every node (bus) in the system – Sum of real power into node must equal zero – Sum of reactive power into node must equal zero l This is a direct consequence of Kirchhoff’s current law, which states that the total current into each node must equal zero. – Conservation of power follows since S = VI* ILMU. KEIKHLASAN. KECEMERLANGAN

FAKULTI TEKNOLOGI KEJURUTERAAN Power Consumpation ILMU. KEIKHLASAN. KECEMERLANGAN

FAKULTI TEKNOLOGI KEJURUTERAAN Example 2. 2 A single phase source delivers 100 k. W to a load operating at a power factor of 0. 8 lagging. Calculate the reactive power to be delivered by a capacitor connected in parallel with the load in order to raise the source power factor to 0. 95 lagging. Also draw the power triangle for the source and load. Assume that the source voltage is constant, and neglect the line impedance between the source and load Answers: 1. The capacitor delivers = 42. 13 kvar ILMU. KEIKHLASAN. KECEMERLANGAN

FAKULTI TEKNOLOGI KEJURUTERAAN THE END ILMU. KEIKHLASAN. KECEMERLANGAN