November 2014

The Institute of Electrical and Electronic Engineers (IEEE) defines power quality as: “The concept of powering and grounding electronic equipment in a manner that is suitable to the operation of that equipment and compatible with the premise wiring system and other connected equipment.” Making sure that power and equipment are suitable for each other also […]

The term power quality (PQ) is generally applied to a wide variety of electromagnetic phenomena occurring within a power system network. The ability of the power systems to deliver undistorted voltage, current and frequency signals is termed as quality of power supply. Unexpected variation of the voltage or current from normal characteristics can damage or

VOLTAGE DIP is a reduction in the RMS voltage in the range of 0.1 to 0.9 pu (retained) for duration greater than hall a mains cycle and less than 1 minute, Often referred to as a ‘sag’, Caused by faults, increased load demand and transitional events such as large motor starting. VOLTAGE SWELL is an

1. What is the “end of useful life”? The IEEE defines “end of useful life” for a UPS battery as being the point when it can no longer supply 80 percent of its rated capacity in ampere-hours. When your battery reaches 80 percent of its rated capacity, the aging process accelerates and the battery should

Quantifying the combined effect of the four factors that affect battery life discussed in the previous page is difficult. You need a way to determine when a battery is near the end of its useful life so you can replace it while it still works, before the critical load is left unprotected. The only sure

In most UPSs, you don’t use just one cell at a time. They’re normally grouped together serially to form higher voltages, or in parallel to form higher currents. In a serial arrangement, the voltages add up. In a parallel arrangement, the currents add up. However, batteries are not quite as linear as the two graphics

Batteries have limited life, usually showing a slow degradation of capacity until they reach 80 percent of their initial rating, followed by a comparatively rapid failure. Regardless of how or where a UPS is deployed, and what size it is, there are four primary factors that affect battery life: ambient temperature, battery chemistry, cycling and

A generating station which utilizes the potential energy of water at a high level for the generation of electrical energy is known as a hydroelectric power station. Hydro-electric power stations are generally located in hilly areas where dams can be built conveniently and large water reservoirs can be obtained. In a hydro-electric power station, water

A modern steam power station is highly complex and has numerous equipment and auxiliaries. However, the most important constituents of a steam power station are: 1. Steam generating equipment2. Condenser3. Prime mover4. Water treatment plant5. Electrical equipment. 1. STEAM GENERATING EQUIPMENT: This is an important part of steam power station. It is concerned with the

In order to achieve overall economy, the following points should be considered while selecting a site for a steam power station: (I) SUPPLY OF FUEL: The steam power station should be located near the coal mines so that transportation cost of fuel is minimum. However, if such a plant is to be installed at a