Q1: Reactive power (Q)
- A: Reactive power is a product of an AC system. Reactive power is used to produce magnetic fields. Reactive power is mea- sured in var, kvar, Mvar.
Q1: Active power (P)
- A: Active power is the useful power that does the actual work. Active power is measured in W, kW, MW.
Q1: Generated reactive power
- A: Generated reactive power of the bank/system is the power generated at the operational voltage, expressed in Mvar.
Q1: Ratio of the active power to the apparent power
- A: Power factor or cosΦ, is a measurement of the efficiency in the system. Power factor describes the relationship between active and apparent power.
Q1: Tuning frequency
- A: The frequency at which the filter impedance, calculated from the rated values, has a minimum or maximum value. (IEC 61642)
Q1: Filter
- A: Filter is a device generally constituted by reactors, capacitors and re-sistors if required, tuned to present a known impedance over a given frequency range. (IEC 61642). Usually active harmonic filter and passive harmonic filter are used in networks.
Q1: Types of reactive power
- A: Shifting reactive power: caused by inductive and/or capacitive loads. These ensure current ‘lags/runs late’ behind the voltage (inductive) or that the current ‘leads/runs ahead’ of the voltage (capacitive). Distortive reactive power: this is the ‘unwanted’ part of the apparent power associated with harmonic pollution caused by non-linear loads.
Q1: In which situations there is reactive power?
- A: To a greater or lesser extent, reactive power is present In each electrical installation. This presence is closely related to the ever-increasing use of electronics and inductive loads.
Q1: In which situations is there NO reactive power?
- A: With an ohmic/resistive load, available power in the installation is directly converted into usable energy. Examples include electric ovens, light bulbs and radiators. The current in this case is in phase with the voltage.
Q1: Excessive reactive power can lead to
- A: 1.Overloading and overheating of the electrical installation and connected components (cables, transformers….) 2.Capacity problems on the installation 3.Unintentional shutdown of installed machines and related business processes 4.An unnecessarily high energy bill due to energy losses 5.A fine from the energy supplier 6.Influence the voltage and quality of the current
Q1: Equipment to solve Power Quality problems:voltage sags and interruptions.
- A: The best choice here depends on extent of any interruption. Uninterruptible power supplies and other energy-storage options could do well with shorter-term sags or interruptions, but back-up generators or self-generation equipment is needed when longer outages are encountered. Other solutions could include static transfer switches and dynamic voltage restorers with energy storage
Q1: first steps in any power-quality improvement program
- A: Measurement and analysis are the critical first steps in any power-quality improvement program. Putting what you’ve learned to use, though, means knowing the best solutions for the problems you’ve identified.
