POWER FACTOR IMPROVEMENT

     The aim of this technical report is to introduce a summary for a study done for Al-Ameen Engineering College for power factor improvement. This report includes an electrical engineering background about the problem of power factor, including: the causes, the consequences, the economical importance for the energy saving for our college and for the Kerala State Electricity Board  as well, and  the theoretical solution for solving that problem.

                    The report links the theoretical solution with the real applicable solution through the study done by our project team for energy planning. This study includes a six months research done by our team, which represents an ideal methodology for solving this problem starting from defining the magnitude of the power factor problem until designing the equipment that can solve that problem.

                   The report represents all the points in simple terminology, according to the objectives of the electrical engineering degree course.

1.1  What Is Power Factor

                   Power Factor is the ratio between the real (kW) and apparent power (kVA) drawn by an electrical load. It is a measure of how effectively the current is being converted in to useful work output and a good indicator of the effect of the load current on the efficiency of supply system. Poor power factor results in increase load current draw that causes additional losses in the supply and distribution systems.

Resistive devices, like electric resistance heaters and incandescent lights transform    all the power supplied to the device into heat or useful energy.  Inductive devices, like motors, use some of the power supplied to the device to energize the inductive windings and create a magnetic field.  This power, called reactive power, is alternately stored and given up by the windings, but is not used to do actual work. When this happens, the line supplying power to the device now carries the actual power used by the device and the reactive power created by the device. 

Actual power used by the device is measured in kW, reactive power created by induction devices is measured in kVAR, and the apparent power in the supply lines is measured in kVA.  The mathematical relationships between these types of power are described by the “power triangle” shown below.  For example,

1.2  Why Improve Power Factor

                 Owing to the nature of machinery that generates alternating current (AC) voltage, the power factor of connected circuits has a direct bearing on the cost of such generation.

                

                 The lower the power factor of the system, the greater will be the non-productive current drawn from the supply, and the power utilities will have to generate much more current than is theoretically required to meet the demand. Therefore the power supply system becomes in efficient, and the cost of electricity is correspondingly increased. The low power factor also means that the size of cabling, switch gear, fuse gear and transformers will have to be greater than necessary and therefore more costly. In such cases, an improvement in power factor is necessary to reduce waste.

                 To ensure that the equipments and cables are not over loaded with reactive current, power utilities often impose penalties for lower power factor