Power quality - challenges and way forward  
Introduction  
Power Quality (also known as PQ) is a highly  
noteworthy issue. Power quality of any country  
portrays its prosperity. Government’s initiative of  
or consuming electricity. So what is the solution?  
The way forward is a single solution which gives  
metered electricity along with the level of quality  
w.r.t. international and national level standards and  
regulations.  
‘Make in India’ has attracted global players to set up  
industries (both manufacturing and services) in  
India. Apart from Government’s support, their  
biggest requirement is quality power.  
Entire Europe is interconnected with a single grid  
and supplies over 400 million customers in 24  
countries. All the connected countries have their own  
power quality monitoring points at interconnection  
points. India is no longer different from Europe as far  
as the electricity grid analogy is concerned. Europe  
comprises a single grid for different countries, while  
India comprises a single grid for different states.  
At present, India doesn’t pose a very good image  
when it comes to the quality of electricity supply. This  
is the major reason for the slow growth of  
manufacturing facilities / plants set up by foreign  
companies. Moreover, we don’t have sophisticated  
industries like semiconductor fabrication plants.  
Present energy metering solutions only measure /  
meter the amount of electricity consumed or  
generated, but they can’t determine the quality of  
electricity. It’s similar to buying milk in our day to day  
life. When buying from a local vendor, we can only  
ensure volume, but there's no means to ensure the  
quality of milk, which varies every single day, even if  
we pay the same amount of money. The same  
theory is applicable for those who are buying, trading  
In 2014, India has achieved a very ambitious goal of  
‘One nation-one grid-one frequency’ by connecting  
all five regional grids together. 2020 must be a year  
for deploying harmonised regulation for power  
quality across all states in India.  
This article begins with a simplified explanation of  
power quality and its relationship with power quality  
parameters defined in standards and regulations.  
Power quality-challenges & way forward  
Causes of poor quality and impacted parties are  
described in the subsequent section. Types of power  
quality issues and their impact level varies  
significantly. Readers will get an insight into  
prevailing power quality regulations, monitoring  
practices and current status. Benefits of continuous  
power quality monitoring are emphasised. Finally,  
the article concludes with strong recommendations  
to the regulatory bodies, utilities, commercial and  
industrial users and renewable energy generation  
companies.  
drivers, arc furnaces etc.) along with rapid  
integration of non-conventional energy sources into  
the grid network throws new challenges for the PQ  
environment.  
Power quality  
Electricity is a commodity and should be fit for  
consumer use. Good quality of electricity possess  
the following attributes:  
Continuity of supply  
Stability of rated magnitude  
Stability of rated frequency  
Purity of sinusoidal waveform  
Symmetry across phases  
Figure 1: Causes of poor power quality  
The supply characteristics randomly vary with time  
and with reference to any specific supply terminal, or  
any given instance of time.  
Any discrepancy in above attributes results in poor  
power quality as depicted below.  
Parties affected by power quality issues are:  
Discrepancy in:  
End users  
Continuity of supply  
Interruptions  
Equipment and system manufacturers  
Designers of plants and installations  
Electricity distributors  
Public authorities  
Stability of rated  
magnitude  
Sag, swell, flicker,  
Under / over deviation  
Under / over frequency  
Stability of rated  
frequency  
General public  
Power quality issues and their impact  
Purity of sinusoidal  
waveform  
Harmonics and  
inter-harmonics  
Voltage and current  
imbalance  
Due to the poor quality of electricity supply, most  
large industries in India incur a heavy cost. This is  
because of:  
Symmetry across  
phases  
investment in costly captive power generation  
unit(s)  
These supply characteristics are subject to  
variations during the normal operation in a supply  
system due to changes in load, disturbances  
generated by certain equipment and the occurrence  
of faults which are mainly caused by external events.  
Increasing use of semiconductor-based electronic  
equipment and non-linear loads (such as computers  
and its peripherals, data servers, adjustable speed  
paying for feeder level above 22kV or an  
express feeder at additional costs  
Industries without the capability of backup supply or  
provisions to work in poor power quality environment  
incur losses because of:  
lost productivity, idle people and equipment  
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Power quality-challenges & way forward  
additional labour cost due to overtime (to meet  
targets)  
harmonic content in loads causes increased  
losses, malfunctioning of electronic circuits,  
heating of power transformers, heating of  
induction motors, premature failure of motors,  
deterioration in power factor etc.  
cost of scrap generated due to poor power  
quality  
costs to restart the plant  
Cost of poor power quality  
equipment damage and repair  
lost orders, goodwill, customers and profits  
Outcome of some surveys are given below, which  
reveals losses to industries due to poor power  
quality.  
lost transactions and orders not being  
processed in time  
A Voltage sag in a paper mill can waste a whole day  
customer and / or management dissatisfaction  
of production - $250,000 loss”  
Variation in voltage, frequency and waveform  
distortion (in other words harmonics) are the critical  
power quality issues. Overloading of an electricity  
network causes voltage variations, resulting in  
increased losses and faults.  
Source: Business Week  
A manufacturing company lost more than $3 million  
in one day last summer in Silicon Valley when the  
lights went out.”  
Source: New York Times  
In India, power quality issues that are typically  
looked at are - harmonics in voltage and current,  
poor power factor, frequency variation and reliability  
of supply using indices like SAIFI, SAIDI, CAIDI, etc.  
Unplanned data centre outages cost companies  
nearly $9,000 per minute.  
Source: Emerson network power study  
Half of all computer problems and one-third of all  
data loss can be traced back to the power line. This  
data is commercially very sensitive and could be  
priceless. The ill- effects of PQ on data centers can  
be drastic.  
In reality, power quality issues in distribution network  
are many more:  
supply voltage fluctuations  
harmonics and inter-harmonics  
sag, swell, interruption  
Source: Contingency Planning Research, LAN Times  
flickers  
asymmetry of three-phase voltages  
rapid voltage change  
low true power factor due to harmonics  
higher failure and cable damage rate  
neutral overshoot  
mains frequency deviation / variation  
Figure 2: Cost due to different power quality events  
Implications of poor power quality to consumers are:  
disturbances in supply voltage (interruption,  
distortion, over voltage / under voltage, sag /  
swell) causes substantial loss of revenue due to  
outages, reduced life of customer equipment,  
relay tripping, flickering of lamps, stalling of  
motors, etc. Also, imbalance of phases results in  
overheating of motors.  
Main conclusions of surveys on costs due to poor  
voltage quality (source: CEER 4th benchmarking  
report)  
Country / year Estimated annual costs  
Norway by NVE Estimated annual costs due to  
and  
dips for end-users between  
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Power quality-challenges & way forward  
In India, there are electricity supply quality  
regulations applicable for generation, transmission  
and distribution companies. The objective of these  
regulations is to help in maintaining the standards of  
the electricity grid and to protect the interest of  
consumers. These regulations have been specified  
by the Central Electricity Authority (CEA) and the  
Central Electricity Regulatory Commission (CERC)  
at a central level and the State Electricity Regulatory  
commissions (SERC) at the state level, as per the  
provisions of the Electricity Act, 2003.  
stakeholders  
2002)  
120 and 440 million  
Norwegian kroner.  
(
Sweden by  
Elforsk (2003)  
Estimated annual costs for  
industrial customers due to  
dips and interruptions  
at about 157 million €.  
Italy by AEEG  
and Politecnico dips and interruptions (< 1 s)  
Estimated annual costs due to  
di Milano  
2006)  
for the whole production  
system between 465 and 780  
million €.  
(
State level regulations cover harmonic distortion  
(mostly THD), voltage variation and voltage  
unbalance. But it doesn’t cover other important  
parameters of power quality like voltage sag, swell,  
interruption, flicker, voltage inter-harmonics, current  
harmonics etc. Also, all states don’t have power  
quality regulations; where they do, they don’t always  
regulate the same parameters, which add to the  
problems.  
Pan European  
survey by  
Leonardo  
Power  
Quality Initiative  
Costs of PQ wastage EU-25  
exceeds 150 billion €  
annually.  
(
2005-2007)  
According to the study carried out by Asia Power  
Quality Initiative (APQI), the direct costs of downtime  
in India are nearly 20,000 crores per annum. About  
Power quality monitoring practices and present  
status  
57 per cent of these financial losses is due to voltage  
sags and short interruptions, while about 35 per cent  
of the losses is due to transients and surges.  
However, the cost of prevention for these may be  
less than 10 per cent of the cost of the problems they  
cause.  
European and developed countries started with EN  
5
0160 as a basis for regulation more than a decade  
ago. PQ monitoring helped to identify weak areas,  
deploying mitigation techniques and their  
effectiveness. Later, they made criteria and  
compliance limits stricter, to further improve grid  
stability. Power quality issues and their impact on  
businesses and consumers are reduced significantly  
in due course of time.  
Regulations on power quality  
basis for voltage quality legislation, regulations and  
standardisation more than a decade ago.  
EN 50160 defines voltage characteristics of  
electricity supplied by public electricity networks  
covering LV, MV and HV. It describes the limits or  
values within which the voltage characteristics must  
be. For example, during each period within a week,  
Monitoring is done mainly at permanent locations  
with the emphasis being placed on substations and  
industries (HV / MV) using power quality metering,  
complying with IEC 61000-4-30 Class A.  
Electrical Industry in the developed world does not  
wait for regulations and frame-work around  
measurement, management and control of power  
quality as these impact their day-to-day business  
and well-being. India is no exception.  
95 per cent of THD values shall be less than or equal  
to 8 per cent. Similarly, limits are defined for mains  
frequency, supply voltage variations, rapid voltage  
changes, flicker, supply voltage unbalance,  
individual harmonic voltages, inter-harmonic  
voltages, mains signaling voltages. This standard  
also specifies framework for statistical evaluation of  
voltage sag and swell by classification based on the  
duration of event and residual / swell voltage.  
In India, big industries install power quality meters to  
identify, solve and manage their own problem. They  
seldom come out in public to challenge causes  
beyond their network boundaries, like poor  
regulation of network, or a harmonic generator  
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Power quality-challenges & way forward  
neighbouring industry. This also means that the PQ  
knowledge is not pooled and leveraged at the  
industry level  
bulk electricity consumers. IEEMA should  
organise induction courses on PQ.  
Regulatory bodies should build and implement a  
regulatory framework with incentive and  
penalisation mechanism for power quality.  
Benefits of continuous power quality monitoring  
Continuous monitoring of power quality can be  
achieved using a fixed, installed power quality  
meter. It conducts a continuous health check of  
the electricity network connected to it, by:  
Electricity metering for revenue should be done  
along with power quality monitoring. Quality and  
quantity of electricity should be considered  
together for billing purpose.  
monitoring harmonics flow between load and  
supply, and its direction  
Distribution companies should monitor power  
quality at the point of interface between Transco  
to understand what PQ they receive and what  
collective actions are needed to improve it, with  
the objective of managing it.  
monitoring power quality events like sag, swell,  
interruption and their severity  
monitoring other important parameters like  
mains, frequency, flicker, supply unbalances, k-  
factor etc.  
Monitor power quality generated by non-  
conventional energy sources at a grid network  
level.  
Such power quality meters are used to view, monitor  
and analyse data to initiate a plant \ equipment  
maintenance programme. These meters also act like  
the black box of an airplane - providing information  
on what went wrong when a poor power quality event  
occurs.  
Power quality performance should be displayed  
in the public domain.  
Utilities should monitor power quality to identify  
‘polluting’ consumers and facilitate efforts to  
reduce the amount of harmonics injected  
harmonics into the network by such consumers.  
In nutshell, continuous power quality monitoring  
detects, records and leads to the prevention of all  
power quality problems.  
Conclusion  
The quality of electrical power is an important  
contributing factor to the development of any country  
and poor power quality of electrical power is  
hindering industrial growth in India. It is estimated  
that every year, a substantial revenue loss is  
suffered by the utility and the industry, due to the  
supply of poor power quality.  
If these problems are not handled effectively, and in  
time, then utilities and their customers may be  
adversely affected in the next few years. It may even  
result in a slower pace of growth for India.  
Here are few recommendations to improve power  
quality:  
Increase power quality awareness among  
transmission and distribution companies and  
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