Power quality and reliability are the key to successful delivery of quality products, services and operation of an industry.
Power quality is now even more critical to industry because of the increasing application of electronic loads and controllers, which are sensitive to the quality of power supplied.
Looking at the present scenario, there is a dire need for all concerned to deliberate on the vital issue of power quality and the latest technologies for mitigation and improvement of power system efficiency and reliability.
With the concept of intelligent and green buildings setting in, various commercial and industrial building utilities are getting centralised control and automated. This calls for a high degree of reliable and safe power distribution system. Bad power quality phenomenon can cause malfunctioning of sophisticated equipment. Harmonics, voltage imbalance, sag and flicker problems, standing waves and resonance are some of the issues that adversely affect production and quality. Those lead to huge losses in terms of product, energy and damage to equipment. Thus, it becomes imperative to be aware of the quality of power and deviation of the quality parameters from the norms or standards to avoid breakdown or equipment damage.
The term 'power quality' means different things to different people. One definition is the relative frequency and severity of deviations in the incoming power (mainly voltage) supplied to electrical equipment from the customary, steady, 50 Hz, sinusoidal waveform of voltage or current. These deviations may affect the safe or reliable operation of equipment such as computers.
Thus, while not having a strict basis of measurement, a term like 'poor power quality' generally means here is sufficient deviation from norms in the power supply to cause equipment malfunction or premature failure. 'Good power quality', conversely, means there is a low level of such deviations or mal-operations.
Automation of the industrial processes has led to effective increase in production and reduction in cost; somehow, the controls in automation are so sensitive to power supply that even minor variations, often perceived as trivial, can create huge negative impact on production and product quality. This can be sorted out from the source itself either by adopting mitigation techniques or by overrating power distribution equipment like transformers, switchgears and cables as required. 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 are not a distant dream. The focus on the dynamic characteristics of the system equipment, while facing the abnormal supply, should not be lost.
Power line disturbances such as voltage sag/swell, outages, flicker, harmonics incur a heavy loss to electric utility customers due to the wide application of the non-linear and electronically switched devices and distribution systems.
Most of the electrical equipment in an industrial facility requires high quality electricity, showing zero tolerance towards power outages, no matter how short-lived it may be. Research shows that 80 per cent of all power quality and reliability problems occur inside end user facilities. A timely diagnosis of the current status of equipment can help prevent major breakdown, process interruption, and thereby, reduce monetary loss. Thus, measuring and/or capturing critical electrical parameters pertaining to the system with the right quality instruments is a must.
These power quality problems may have different causes. Some problems are a result of the shared infrastructure. For example, a fault in the network may cause a dip that will affect some customers. The higher the level of fault, the greater the number of customers affected. Other problems, such as harmonics, arise within the customer's own installation.
Harmonic load currents include
1. Single phase loads, e.g. - Switched mode power supplies (SMPS).
2. Electronic fluorescent lighting ballasts.
3. Small un-interruptible power supply (UPS) units.
4. Three-phase loads, e.g., - Variable speed drives - Large UPS units.
Currently one comes across a daily report of some devastating fire in buildings whether swanky new commercial buildings like Naman Midtown Tower at Elphinstone Road (Mumbai) or an old building like the CST Admin Building at Mumbai or seat of power like Mantralaya in Mumbai. One must recognise that fire or electrical accidents do not discriminate between have or have-nots; nor even between rich and poor; nor between powerful people or common people. We not only are exposed to danger of losing life but also part of our history. But life goes on since we are indifferent to the poor PQ environment that is part and parcel of our digital life unless addressed step-by-step. One interesting common denominator one might note that it is often caused by 'electrical short circuit' or 'fire started from server room'. Once life is back on rail, business as usual prevails and all forgotten. No one wants to drive deep and take steps to prevent such occurrence in future.
Addressing PQ thus becomes more critical but often sidelined in the demand-supply gap environment or utility citing the reason such as 'it is the customer's problem' and they should solve it. Such attitude often springs out of inadequate information on enormous economic loss that we suffer as a result of poor PQ including life and property loss. So it never surfaces on the policymaker's horizon of vision. We fail to recognise that in smart grids and intelligent building era, it is all the more vital to address PQ.
It is increasingly being accepted that the impact or poor power quality on organisations' operational efficiency is significant and disruptive. It is also observed that financial impacts are far greater than what had previously been recognised. In fact, it has been estimated that the total cost to US businesses of this lost productivity is a staggering $15-30 billion per year. A survey done by Leonardo Power Quality Initiative (LPQI) in eight European countries revealed that the cost of wastage caused by poor power quality exceeds 150 billion euro. Industry accounts for over 90 per cent of this wastage. A recent survey in US indicated that, while most respondents did not calculate the cost of their annual losses due to power quality (or may even erroneously attribute power quality glitches to software or hardware causes), roughly a third of those that did report a loss figure said it exceeded $I million per year. Unfortunately for us in India such a comprehensive study is yet to be done. A rough dipstick approach indicates that we may be losing 1 per cent of our GDP due to poor PQ environment keeping aside the deficient supply at many parts of our country.
Surprisingly, improving power quality does not require massive investments. In many cases, simply installing enhanced electrical systems and better grounding systems will prevent (or solve) the problem. Many of the simple techniques are relatively inexpensive to install during construction, or during major building renovation. It is estimated that the preventive actions are estimated at 5 per cent of the annual losses for a specific site. Further, since the use of a particular building or area within a building may vary considerably over the years, the recommended infrastructure improvements will serve to make the building more useful over time, despite changes in tenants, end users or equipment.
Another aspect that pushes PQ out from the discussion table is the reason that most of the distribution companies (especially one from State-controlled monopoly legacy) feel their assets or systems are not affected by poor PQ environment and addressing distribution loss is the only job to be carried out for survival. Recognition of customer's right to have quality power is still to take deeper root in absence of strong independent regulatory supervision and enforcement like in most other cases. In spite of having myriad problems in hand the utilities must undertake responsibility to address poor PQ and do some hand-holding of customers in addressing PQ for a win-win situation.
Power quality is an area with lots of information gap and is often misunderstood from the viewpoint of its potential to cause damage. The effect of power quality deficiency is not quantified accurately. Also there is no national level study showing the gross national level loss due to power quality insures.
For cost-competitiveness, industries are more concerned about direct power cost (physically visible through the bill) rather than the end effect on product quality or process due to power quality, which manifests itself in an intangible manner.
The solution providers, spanning from multinationals to next-door system integrators, often do not work in tandem. Lack of clarity and knowledge at customers' end often makes the environment non-conducive for solution providers.
This article has been authored by Manas Kundu, Director Energy Solutions, International Copper Association India (ICAI)
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