Generally, Power quality is an issue that is becoming increasingly important to electricity consumers at all levels of usage. Sensitive power electronic equipment and non-linear loads are widely used in industrial, commercial and domestic applications leading to distortion in voltage and current waveforms. With ongoing regulatory, policy and structural changes in the Indian electricity industry, following the Electricity Act 2003, the issue of power quality is poised to become a figure-of-merit amongst the competing distribution utilities. Improvement of power quality has a positive impact on sustained profitability of the distribution utility on the one hand and customer satisfaction on the other.
Electrical power is perhaps the most essential raw material used by commerce and industry today. It is an unusual commodity because it is required as a continuous flow- it cannot be conveniently stored in quantity - and it cannot be subject to quality assurance checks before it is used. The reliability of the supply must be known and the resilience of the process to variations must be understood. In reality, of course, electricity is very different from any other product – it is generated far from the point of use, is fed to the grid together with the output of many other generators and arrives at the point of use via several transformers and many Kilometers of overhead and possibly underground cabling. Where the industry has been privatized, these network assets will be owned, managed and maintained by a number of different organizations.
Assuring the quality of delivered power at the point of use is no easy task – and there is no way that sub-standard electricity can be withdrawn from the supply chain or rejected by the customer. From the consumers’ point of view the problem is even more difficult. There are some limited statistics available on the quality of delivered power, but the acceptable quality level as perceived by the supplier (and the industry regulator) may be very different from that required, or perhaps desired, by the consumer. The most obvious power defects are complete interruption (which may last from a few seconds to several hours) and voltage dips or sags where the voltage drops to a lower value for a short duration. It is now even more critical to the industry because of increasing application of electronic loads and electronic controllers which are sensitive to the quality of power supplied. Bad power quality can cause malfunctioning of equipment performance. Latest innovations for askance distribution system design; including high reliability distribution systems using high-speed fault detection, rapid fault clearing, fault isolation and automatic restoration systems is not a distant dream.
Most of the electrical equipment requires high quality electricity, showing zero tolerance towards power outages, no matter how short-lived it may be. Research shows that 80 % of all power of all power quality and reliability problems occurs inside end-user’s facilities. A timely diagnosis of the current status of equipment can help prevent major breakdown, process interruption and reduce monetary loss. Thus, measuring critical parameters pertaining to the equipment with the right quality instruments is necessary.
Acute power shortage of course has created an alarming situation in the country. This apart, power quality problems like voltage fluctuation, frequency variation, generation of spikes, impulses, surges and sags, harmonics, high earth leakage current, missing cycles, black-outs, brown-outs, etc. are playing havoc on our assets. Besides downtime and production losses they cause incalculable damage to our costly capital equipment. Modern industrial equipment are more sensitive to these power quality problems than before and need higher quality of electrical power. The basic reason is that the minor power disruptions which one would have...