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, says Manas Kundu.
Power quality (PQ) and reliability is the key to successful delivery of quality product and uninterrupted operation of an industry, be it conventional or service sector. It is now even more critical to the industry because of the increasing application of electronic loads and digital controllers which are sensitive to the quality of power supplied. These can have serious economic consequences and cost business millions of rupees each year in revenue loss, process improvements, opportunity loss, equipment failure, electrical hazards like fire and scrapped product. 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 building setting in, various commercial and industrial building utilities are getting centralized control and automated which calls for high degree of reliable and safe power distribution system. Digital economy demands quality power and while being sensitive to such power quality environment they themselves are also cause for polluting the power quality environment. The world has changed. We are no more in pure sine wave era controlled by linear loads; rather we are almost fully controlled by non-linear loads. In the world of power electronics, bad power quality phenomenon can cause malfunctioning of sophisticated equipment. Harmonics, voltage unbalance, sag and flicker problems, standing waves and resonance are some of the issues that adversely affect production and its quality, leading to huge loss in terms of product, service, energy and damage to equipment. Thus, it becomes imperative to be aware of quality of power and the deviation of the quality parameters from the norms or standard to avoid breakdown, service failure or equipment damage.
How we define PQ is determined by our perspective. This general definition covers both the user's perspective and the utility perspective. power quality is a set of characteristics of the electrical power supply and the electrical system. Power quality is also a set of characteristics of the load and it's influence on the supply voltage. Industry requires standards to benchmark and address issues of power quality. Today we are mainly following American or in some cases European Standards. But home grown standards to suit our own environment are a must. Take the case of domestic inverter a unique case that only exist here and nowhere else in developed world. Another case of voltage stabiliser to protect our domestic and sensitive industrial equipments is very unique to our environment.
The recent demand for more efficient use of electricity is impacting power quality both at the user level and the utility level. The correlation between power quality and energy efficiency is not well understood though energy efficiency drives have now caught serious attention of both the industry and commerce. There is neither any published study in India on the impact of energy efficiency improvement devices on power quality nor any national product standards that could address the issue. Need is to explore each technology of device and it's impact on power quality. Various equipments (see fig 2) those are perceived to contribute to poor power quality environment; though they are governed by national product standards (BIS), might not have PQ dimension at all. The technologies for investigation could include: Variable Speed Drives (VSD) for motors, Light dimmers, Fluorescent lamps, LED lamps, Computer power supplies and Power Factor improvement capacitors /filters, inverters /UPS etc. Recent effort and barriers faced by BEE and BIS while formulating CFL standards is a pointer to this gap. Need exist for testing each technology that improves the efficiency of the loads or the electrical system as well has some positive and negative impact on the power quality or increases the sensitivity of loads to power quality characteristics.
Debate surfaces time and again on Electro Magnetic Interference or Electromagnetic Compatibility (EMI/EMC) issues and Effects on human life. Recently the Union health ministry commissioned the first large scale study of the effects of radio frequency radiation from mobile phones on humans. With around 800 million (as on March 2011) mobile phone subscribers currently in India, and many more using other appliances like television, computer, inverter based air-conditioners, vacuum cleaner, microwave etc, usually found with high frequency radiation the fear is that these 'essentials' of life may actually be posing a big health risk because of their electromagnetic fields (EMFs).
Recent times we also have seen that both at IEC level and also at British Standard Level the issue of electromagnetic compatibility whether for fixed installations or for equipment characteristics have been addressed in detail through standards like BS - 7671 (2008) specifying requirements for electrical installations, but such efforts are completely absent at our national standards level. In absence of any mandatory EMC directive, like in EU (EMC Directive 2004/108/EC), in our country today there is no thrust by designers on considering system performance requirements from power quality perspective. If this is not being implemented, potential PQ site problems may surface very quickly post-commissioning. Our old distribution systems are given make up with latest electronic gizmos but without knowing the effects. Recent spate of infernos across India should be wake up call. It would be interesting to study or technically investigate for quantifying the wiring system losses due to non linear loads harmonics for typical installations in commercial buildings (high rises). Such study might enable us to disseminate the findings to designers and users of commercial buildings and industries for PQ mitigation coupled with energy efficiency.
Power quality is attracting increased attention due to the proliferation of power electronic systems in the consumer market. Power electronic circuits cause distortions in the current and voltage waveforms, reduce the power factor and make the conventional measuring instruments function erroneously. They affect adversely the functioning of other power electronic systems such as adjustable speed drives, personal computers, power supplies etc. resulting in failure of circuit breakers, capacitors and loss of data. Although internationally there have been stringent power quality standards available from electrical standard organizations like IEEE and IEC, in India, there is no such standard available from any of the organizations like BIS or CEA or ERCs. Some of the state regulatory commissions are trying to prescribe some standards regarding supply interruption (SAIDI, SAIFI, CAIDI, CAIFI indexes), frequency, voltage magnitude and harmonic distortion. However given the poor health of the utilities and majority approach of business as usual to opt for load shedding to tide over availability crisis, it is doubtful if they would be interested in pursuing power quality with all eagerness. The business case can best be described in the fig 3 below:
Under the current business as usual arrangement, the utility companies (DISCOMs) in order to maximising their profits will minimize their costs, in point A, but here the outage costs are high. But the socio-economic optimal point is in B, where the sum of outage cost and the companies' cost are at the lowest. May be on the introduction of Cost of Energy Not Supplied (CENS) through regulatory intervention the companies will be better off by balancing their internal costs and quality of supply towards a socio-economic optimum. In any case, it is a long way to go when one can see in our country a negotiated contract for quality electricity supply between an utility and a large industrial consumer.
Economic Loss Due To Poor Power Quality:
The massive economic loss that could be suffered by industries is not well understood or captured today at the industry level. Neither there exist any systematic study. Some time back a Universal Consulting study, done for Wartsila India, based report (August 2009) indicated that India suffers a staggering loss of INR 100,000 Crore (1000 Billion) due to nationwide power outage. It also indicated that Indians are spending Rs 30,000 crore (300 Billion) annually to operate inefficient power back-ups using gen sets and inverters. But that is only limited to loss due to energy not supplied. No one has any idea about the cost that arises out of poor power quality. A recent joint study on 'Impact of PQ in Indian Industries' undertaken by IIT Delhi with Asia Power Quality Initiative (APQI) concluded as follows:
'Almost all the industries suffer due to various power quality problems. In fact, many of the industries are not even aware of various PQ problems like harmonics, flickers etc. They do not even possess equipment to measure these aberrations in power quality. It is a must to educate and create awareness among industries regarding power quality. This calls for BIS taking a firm and bold step to introduce power quality standards that are suited for our country. For this, academicians, industrialists, consumers, utilities and regulatory bodies should come together and have several thorough brainstorming sessions. This will create a healthy and reliable power grid and utility in our country enhancing productivity and GDP growth'. .
So we are still far away to assess realistically the economic impact of poor power quality. But some of the developed world study is a clear pointer of the size of iceberg that we might be threatened of.
A study done in Europe over a period of three years estimated that EU suffers from a loss of Euro 150 billion per annum due to various power quality issues (see Fig 4a). The same study also has concluded that equipments are most vulnerable (see Fig 4b) from poor PQ impact.
Acute power shortage of course has created an alarming situation in the country. Policy makers are deeply engaged in solving much exasperating demand û supply gap problem 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 critical assets. Besides downtime and production losses they cause incalculable damage to our costly capital equipment and consequent to the economy.
Power line disturbances such as voltage sag/ swell, outages, flicker; harmonics can cause a heavy loss to electric utility customer. This is due to the wide application of the non-linear and electronically switched devices and distribution systems aspiring to elevate into Smart Grid. At the same time, modern industrial equipment are more sensitive to these power quality problems than before and need better quality of electrical power. The basic reason is that the minor power disruptions which one would have noticed only as momentary flickering in the lights, may now interrupt the whole automated factory assembly lines with sensitive electronic controllers or make all computers in an office go blank at once.
The generally encountered power quality issues are voltage dips and fluctuation, momentary interruptions, transients, etc (see fig5). Except the power outages and transients due to lightening, other power quality problems like sags, swells, short term interruptions, harmonics, distortions, etc. occur either due to some faults in distribution feeders or interference from loads. During short circuits, fault clearing process in feeder or even heavy loads switching in/out, the neighbouring feeders can get affected with sags or swells in the supply voltages. It is matter of time to see if the Smart Grid idea could address PQ or accentuate the problem further if not addressed right at begining.
Issues and initiative to address them:
How do power quality problems occur? How do we go scientifically auditing power quality problems? How do we manage power quality? What are the technologies, equipment and systems and standards available for the ensuring continuity of quality power and conditioning it?
Power quality is an area with lots of information gap and often misunderstood from the view point of its potential to damage. The effect of power quality deficiency is not quantified accurately. Neither there is any national level study bringing out the gross national level loss due to power quality issues.
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 PQ which manifests itself in an intangible manner. The solution providers, spanning from multinationals to next door system integrator, often do not work in tandem. Lack of clarity and knowledge at customer end often makes the environment non-conducive for solution providers.
These are the areas where Asia Power Quality Initiative (APQI) has stepped in to provide a neutral platform for comprehensive knowledge resources and free sharing of such experiences amongst all stakeholders. The aim is to build up the capacity, facilitate policy debate, facilitate market transformation and information dissemination through shared learning. In Europe, a role model has been set up by Leonardo Power Quality Initiative (LPQI) which has become a larger movement with diverse knowledge base. LPQI is a credible non-commercial voice for sharing good things i.e. learning. Having LPQI as a background knowledge base, International Copper Promotion Council India, a not for profit organisation, is customizing the learning's for India under the umbrella organization; Asia Power Quality Initiative (APQI) India to assist the cause.
The author is Director (Energy Solutions), International Copper Promotion Council (India). The Asia Power Quality Initiative (APQI)
The Asia Power Quality Initiative (APQI), which has national support networks in India, China and Thailand, is now also working in several other Asian nations, namely Malaysia, Philipines, Vietnam and Indonesia. The platform works with three key objectives:
Knowledge exchange through seminars, studies and other interactions has helped APQI reach out not only to energy managers and electrical engineers from manufacturing industries but also utility managers and engineers of data processing centres, commercial buildings, stadiums and gymnasiums, hospitals, broadcast and television stations, the telecommunications sector, financial enterprises, transportation industries, and IT/ITES buildings. Beneficiaries also include students in electrical engineering and electrical systems design.
APQI leverages the scale and reach of the global Copper Alliance and The International Copper Promotion Council - India (ICPCI), which is the Indian co-ordinator in the APQI project. We use our web site, a rich team of resource persons and our membership base to reach out to even more and make PQ a subjet of discussion among the target audience and policy makers.
Development of local content
The APQI project has a rich data base of studies, surveys, technical material and e-learnng software. However, not all of the material is built or written for the Indian market. There are as many as 36 case studies focused on India but we want to build more. Members of APQI India have technical expertise in PQ could therefore contribute actively to the development of technical articles, case studies or training materials that are tailored to the Indian situation. Contributors may be invited to participate as delegates or panel members of national and international workshops and conferences. At APQI, all content is shared in a transparent manner and is also put up on the APQI web site.
The APQI project was launched with co-funding from the European Commission via a grant and tenure that ended in May 2010. But improving PQ is a long-term effort in communications and in building the capacity of engineers and electrical systems designers. While much of the necessary materials and tools required to support capacity building activities have been developed through the project, APQI India continues dissemination and capacity building activities and has expanded its activities at a time when the economy is modernising and PQ is becoming important for our market.