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kVAh metering: magic solution or an aberration

by Surendra Jhalora


The search for innovative solutions has lead to the concept of kVAh metering. Measurement of kVAh and related tariffs are expected to help in reducing reactive currents in the system by commercially motivating consumers to install reactive compensation at their premises. A changeover from the conventional kWh metering to kVAh metering is therefore seen by a few as a magic solution for the Indian power sector. This paper examines the less visible and less magical aspects of kVAh metering. The paper looks at the kVAh in totality by examining the commercial aspects, regulatory aspects, legal aspects, technical aspects, and the controversies it is likely to generate. The paper concludes that there is an aberration in the concept of kVAh metering and a changeover to kVAh metering will not bring real benefits but cause unnecessary expense to unsuspecting consumers and distribution utilities.


The advent of electronics has opened new avenues for creative thinkers and manufacturers to invent innovative metering solutions for the power sector. This is evident from electronic meters, which are now available with a host of load survey and tamper recording features. Innovative thinking leads us to conceptual issues as well to imagine metering solutions, overlooking basic electrical concepts and ignoring legal, commercial and practical aspects.

It is important that new concepts are carefully examined from a totality. One such new concept sweeping the length and breadth of this country is kVAh metering.

kVAh metering

kVAh metering is a concept mooted to replace the conventional kWh metering. It suggests that consumers must be billed as per the kVAh (apparent energy) drawl, and not as per the kWh (active energy). Implementation of the concept will mean that at each consumer premise a new type of meter will have to be installed, one which records kVAh

A magic solution

It is all too well known that abnormal voltages, typically low voltages, plague distribution systems in India. Reactive power flows in the network cause a reactive drag in the interconnected transmission system and reduce the system stability. This in turn requires a reactive compensation in the system.

The transmission and distribution utilities invest a large amount of money every year to install capacitors in the system. It is seen that even after two decades of capacitor installation programs it is found that still more capacitors are required by the system. It appears as if the requirement can never be fulfilled.

The source of most reactive currents is the poor power factor loads connected at consumer premises. Each of these loads could have been compensated by appropriate capacitor installations, had the brunt of capacitor installation shifted from Utilities to end-consumers. This is not happening today because there is no commercial inducement for consumers to care for the reactive energy drawl by them. Many countries have legislation that prevents electrical equipment and devices with low power factors from being sold.

Introduction of kVAh metering and kVAh tariffs is therefore seen as a commercial inducement on consumers to ensure a smaller electricity bill by ensuring that they do not draw reactive power. It is imagined that these consumers will in turn purchase electrical devices with power factor correctors, or install capacitors at their premises.

If this is achieved, it is easy to see how a large amount of precious energy will be saved due to the reduction of technical loss in the system due to accruing from a reduction in reactive currents. It is also easy to see imagine a large amount of money will be saved by utilities, who need not invest money for capacitors for compensation or voltage improvement.

It is easy to see imagine how changing over from kWh metering to kVAh metering will bring about a nationwide revolution in energy efficiency, and therefore this appears to be a magic solution for the country.

Fundamentals of commercial measurement

The fundamentals of any commercial measurement are, measurement of the commodity being sold (i) in a transparent manner (ii) using a controversy-free and accurate measurement tool. For electricity, the commodity being sold is active energy (kWh).

This commodity (active electrical energy) is generated from non-electrical energy resources (like coal, gas, renewable energy sources etc.) by electrical generators and purchased by end consumers to be used for operating electrical devices to do mechanical work , heating, lighting etc for them. The distribution companies are transporters of this electrical energy and therefore bill the consumers as per energy consumed by each consumer. This is the arrangement today, and that is why the kWh metering has been accepted as the proper measurement tool.

Apparent energy, which is kVAh, contains a component called reactive energy (kVArh) whose generation is not directly related to conversion of energy resources. This reactive energy component may be necessary to support delivery of active energy, but it is not useful to the end consumer for conversion to any active work or output. Hence it may be said that apparent energy (kVAh) is not a commodity that the user wants to use and nor it is a commodity that transporters (i.e. distribution companies) transfer from generating stations. To have commercial measurements and tariffs solely based on such a commodity (kVAh) is simply irrelevant.

Electricity is metered to meet two objectives (i) To account for active energy transmittals, that is, energy accounting (ii) For commercial metering, that is, to make a consumer pay for the electricity he or she has consumed. There needs to be accounting at every stage, and hence kWh is accounted for, right from the generating stations, through the transmission and distribution lines,
and as delivered to end consumers, through the present kWh meters. All this is not possible if kVAh meters were used.

Accounting of kVAh is not possible in any scale, as all “apparent energies” do not add to give the “total apparent energy”. More so, sum of three apparent energies in each of the three phases does not add up to give the three phase apparent energy. This exposes the vulnerability of the term “apparent energy” which is nothing more than electrical engineers’ “jargon” rather than a
definable energy tariff parameter in the scientific lexicon, which can be legally used for tariff purposes. Remember the law of conservation in physics governs “energy” where all input energies must add up to be equal to the sum of output energies and losses.

The kWh metering presently in use provides the mechanism to monitor the quantum of energy purchased and sold, so that (i) the distribution utility can maintain an account for the energy it has purchased, sold and lost, and (ii) fair tariffs can be formulated with allowances for losses and fixed charges/overheads. A change to kVAh disturbs these objectives without giving any great over-riding advantages.

kVAh tariffs are never equitable

Reactive power (and resultant reactive energy which is a component of apparent energy) is a locally generated phenomena. It is a necessity for flow of electricity in any system, but not something that is generated by generators and transferred over the lines to end consumers. The kVAh drawl by a consumer for the same connected load will vary depending on the voltage at consumer premises. As voltage at which power is delivered to consumers is under control of the distribution company and not consumers, it is unethical and unequitable to bill consumers as per their kVAh drawl. Well, kWh drawl by consumers are also affected by voltages, but a consumer does not have to “adjust” or “compensate” his consumption when voltages are poor and still land himself or herself at a financial disadvantage.

Reactive power is necessary to support the voltage of the system, and the uncontrolled use of reactive power adversely affects the system voltage. Though reactive power cannot strictly be called a saleable commodity, its over-drawl (or over-use) can at
times be seen as a “violation” by the consumer.

Hence it is appropriate to view poor power factors as a “violation” and not as a “consumption”. As this is not a “consumption”, there is no justification to base tariffs on apparent energy. A penalty can at best be levied for any violation. It is therefore inappropriate to replace the tariff for the commodity being sold (kWh) with a tariff for kVAh just because we want to deter violations. A poor power factor penalty (or demand overshoot) is more appropriate than kVAh based tariffs because penalties generally have two very fair components (i) a limit for which there is no penalty – a warning factor (ii) a penalty for violations beyond the allowable limit – that is a penal component.

A kVAh tariff on the other hand does not give any allowable limit as a warning. It operates like Shylock, demanding its pound of flesh for every single moment of drawl beyond the almost “impossible to maintain” magic figure of a perfect unity power factor.

Once kVAh tariffs are in place, excessive reactive drawls can no longer be considered as a violation. Consumers who do not care to reduce their reactive drawls will have no qualm paying a little more. They may leave their capacitors connected during off-peak hours and force the voltage to increase at night hours affecting the system and other consumers connected to the system. It is equally possible that consumers may not connect capacitors at all and draw reactive power heavily from the system pulling down voltages.

And, who suffers? The commercially conscious consumer who invests to compensate his loads perfectly is the sufferer. He spends money to install switched capacitors so that he may not pay higher kVAh bills. Yet he is forced to consume a higher kVAh because he can never maintain his power factor at unity, simply because the distribution utility cannot maintain the voltage at his supply point. That happens because the power factors of loads are influenced by voltage.

Reactive drawl or injection can be useful depending on the prevailing voltage conditions. When the voltage is low a reactive injection helps the system; when the voltage is high a reactive drawl helps the system. The kVAh tariff does not encourage this to happen.

For these and many more reasons, kVAh tariffs can never be considered fair or equitable for either consumer or the utility. A deeper thought will explain why the kVAh tariff will not be much useful for the utility as well once we understand whether it will deter poor power factors and whether the power factor problem is really that serious.

Will Kvah tariff provide a commercial deterrent for poor pf Yes. kVAh tariffs will always tend to provide a commercial disincentive for reactive indiscipline for a few consumers, but just a minuscule few who can understand the concept of PF and have the intention to keep their bills under control. The habits of the masses are more likely to remain unaffected. The average consumer, who might intend to control his PF also would not be able to do so as he has no means of monitoring what his power factor is. An example of problems that may be encountered, in case a change over is planned from kWh to kVAh, may be seen from the example of frequency linked availability tariffs – an ideal example of providing commercial signals for a disciplined inter utility operation.

In availability tariffs, maintenance of MW drawl schedules, generation schedules, drawls from the grid etc. are to be paid based on pre-decided contracts. The deviation from schedules is to be measured and charged at rates which are related to the incremental cost of generation in the system, such incremental cost being determined from the grid frequency. So perfect and simple a proposition, but so hard to gain unanimous acceptability. It may be noted that here also, the stress (or commercial deterrent) is based on kWh and not kVAh. The voltage linked reactive drawls (in the proposed inter-utility tariffs) are more in nature of a penalty than a tariff.

The availability tariffs has not found unanimous acceptance with just a few Indian power utilities, in spite of it being based on sound techno-commercial principles. If this be the case with just a few utilities, how do we expect millions of end consumers to accept a change-over to a clearly faulty kVAh metering and tariff system

In case the kVAh tariff is implemented, there will be only a few consumers who understand power factor. Maybe, these few will try to economize on kVAh drawls. It is for sure that the majority will find kVAh hard to comprehend. In the Indian scenario where we cannot educate consumers to save electricity and conserve energy, how can we educate them kVAh management. In a scenario
where we are plagued with abnormally high losses (mostly non technical) of more than 50%, it looks too out of place to ignore these problems and be bothered about changing the commercial metering from kWh meters to kVAh meters at a phenomenal cost to the exchequer, just to save maybe 1% or so of energy.

Is there clarity and consistency in principles of kvah measurements

It is necessary that consumers are educated on what kVAh metering means, its benefits and how it will be put in use. It is the duty of the promoters of kVAh metering to explain how kVAh is defined and how it can be measured in an unambiguous manner. That is because there is little clarity and much disagreement on even the definitions of kVAh. Unlike kWh, for which there is little argument or debate, there are different ways of measuring kVAh, each of which will lead to a differing value.

Is kVAh the Pythagoras sum of kW and kVAr integrated over time, or is kVAh a product of root mean square voltage and current integrated over time. These different methods would give different results in the case of unbalanced loading in three-phase systems.

How does one define the RMS value for kVA, and how do we treat harmonics. How do we define and distinguish between “fundamental” and “harmonic” for kVAh. What kVAh value must be measured, and what must be the measurement principles. How do we test for metrology and which standards to follow?

What happens when one phase draws a lagging current (say 0.5 lag), the second phase draws a leading current (say 0.5 lead) and the third phase draws current at unity power factor. How do we measure the kVAh for a three-phase with unbalanced power factors using 3 phase 3 wire measurements? The kVAh itself is shrouded with ambiguity and inconsistency, at least for the majority of power sector engineers. Educating consumers on such aspects will always remain a far cry.

One might be inclined to think that it is easy to define “anyone” principle as the correct – but this proposition is beset with problems as there are serious inconsistencies that such measurements may have. Take for example the following:

  • While active energy is a vector quantity, it has a direction and can be conveniently added, the apparent energy is a scalar quantity and can not be added under varying PF conditions. This will lead to varying bills by two otherwise perfectly legal apparent meters, just because their integration periods were different !
  • A windmill that generates active energy and draws reactive from the system, it will get more money for drawing more reactive energy from the system.
  • Many people take recourse to the IEEE study group’s definition of apparent energy, notwithstanding the fact that these definitions were evolved with the intention of measuring pollution and determining factors for penalizing pollution rather than defining “energy supply tariff” based on them. The IEEE definition for apparent power is :S2 = (VI)2 = (Vf + Vh )2 * (If +Ih )2 = (Vf x If )2 + (Vf x Ih )2 + (Vh x If)2 + (Vh x Ih )2WhereVf =Vfundamental Vh =VharmonicIf =Ifundamental Ih =IharmonicIt then goes on to define a fundamental apparent power ” Sf ” and a non fundamental power “ Sn ” as follows:Sf = Vf x If , the product of the fundamental components of the voltage and current.Sn = {(Vf x Ih ) + (Vh x If) + (Vh x Ih ) }Sn/Sf being considered the ideal figure of merit for determining harmonic pollution and penalizing.It is not difficult to see from this analysis that if a consumer is consuming unity power factor load and purely sinusoidal current, the presence of harmonics in voltage itself increases his apparent energy consumption. As concepts remain hazy, it shall be hard for most manufacturers (barring just a few market leaders of electronic meters of today), to comprehend technical requirements and manufacture suitable kVAh meters.So, can kVAh be computed by the multiplication of the RMS values of Voltage and Current. As emphasized above, the issues of power factor and kVAh under harmonic conditions will have to be kept in view and there is no clear solution to the problem. If so, how do we define kVAh under harmonics?

There is also no unanimity as to whether kVAh computed must consider lagging kVArh alone or both lag and lead kVArh. Different engineers suggest different methods. Some engineers suggest that kVAh is to be computed considering only the lag value of kVArh. Others insist that both the lag and lead values are to be considered. In the former method any leading power factor is considered as unity. As the debate rages, no unanimity seems to be in sight and unless a decision is reached no kVAh tariff can be implemented.

Let us not be carried away with definitions issues alone. Definitions may be sorted out in course of time, technically compromised, or even mutually agreed. It is not only these definitions but other important issues as well, like commercial and legal issues, the financial repercussions, ethical issues, practical issues, whether at all there is a dire necessity for a change, and issues relating to the impossibility of energy accounting, etc. that taken together warn us against any change from kWh to kVAh. Surely, the changeover is going to have a phenomenal impact on a number of such aspects, and that is why we must treat with utmost care.

kWh versus kVAh

When a consumer pays for electricity, the effective electricity rate he pays comprises of three components, which may not be visible in the final unitary tariffs. These components are:

  1. Energy purchased from the generating stations or grid (kWh)
  2. Energy loss incurred by the distribution utility (kWh)
  3. Annual charges for the distribution system (this includes ROE, O&M etc.)

The last part (annual charges) are linked to the system kVA capacity. This kVA capacity determines the total demand that can be sanctioned to consumers (after considering appropriate diversity factor).

That is why it is appropriate to have a tariff based on kWh and not on kVAh. Exceeding the sanctioned kVA demand value means that the system is utilized beyond its design. This should invite a penalty as is already the case in most tariffs, and not legitimized through a kVAh tariff. This penalty can, if necessary, be extended to domestic sector as well and this will appropriately address the poor power factor problem.

There is one more aspect, particularly in end consumer tariffs, and that is cross compensation in tariffs between two or more consumer categories. This aspect needs to be kept in consideration while examining the viability of kVAh metering. The cross compensation can be worked out only if the exact quantity of energy consumed by each category is known. In case the meters of all consumers were to be changed from kWh to kVAh it will be difficult to work out cross subsidies in a transparent manner.

Imagine a scenario where consumer meters do not register any active energy. For such a scenario it would become impossible to account for energy and loss in the system, particularly the loss in the “highly-loss-prone” LT system. It would also become difficult to arrive at reasonable figures for cross compensation in tariffs as energy delivered to each category of consumers cannot be determined in an unambiguous manner.

One of the foremost problems of our power supply and distribution system is losses. In order to address this problem, we have to resort to energy accounting at every level. Introduction of a kVAh based metering scheme will completely seal the possibility of energy accounting by conventional methods.

Why penalties and not kvah metering

There are two things catered for by the distribution utility (i) capacity (ii) energy. Every consumer has sanctioned a particular capacity based on which the distribution system has been constructed. Violation of the capacity is an offense on the design of the system, and hence deserves a penalty, like demand over-shoot penalties. The consumer is expected to draw electricity within the sanctioned demand limit, and a kWh metering is appropriate to measure his drawl.

kVAh metering on the other hand is a measuring system that gives a commercial warning to consumers to use electricity at the unity power factor. It does not directly measure the electricity consumed by consumers. It is never the case anywhere in the world that all electrical devices are supposed to have a unity power factor. It is not denied that electrical devices need compensation. But kVAh metering tends to imply that consumers are to have perfect compensation. This as such is not only an anti-customer but impractical proposition. This puts forth a technical condition which the unaware common masses just cannot fathom or comply, however good their intention may be. Hence it is both unethical and anti-customer.

It is also anti-customer because it implies that the distribution utility commercially denies the customer the right to freely draw electricity (within his sanctioned limit). It is fair to tell the customer not to draw power at poor power factors and even penalize violations, but it is not in line with fair business ethics to have a commercial system in place, which the customer just cannot put in practice for his best benefit.

Why not look at a similar issue facing the distribution companies, who in turn are customers of generating companies. The distribution companies often ask (at times demand) the load centre generating stations to supply VARs, for which they do not pay. The generating stations in turn sacrifice their active generation to generate VARs to meet the reactive demand in the grid.

Pit head stations with long transmission lines have to operate at leading power factors often sacrificing their stability. If at all kVAh is to be paid in the form of tariffs, will at all the distribution utilities agree to pay generating stations based on their reactive generation. On the other extreme, if at all kVAh tariffs were applicable for generating stations, they would possibly be too happy to save their coal consumption and raise bills on distribution utilities based on kVAh delivered. In proposed inter-utility tariffs there is a penal component linked to reactive drawls which are linked to voltages, with a band of voltage for which there is no reactive energy penalty.

However, a kVAh metering has no such band. How can we have double standards, one between the generating companies and distributors, and other between distributors and end consumers? How do we deal with end consumers who are directly supplied power from generating companies’ needs also to be kept in consideration? That is why kVAh metering will sooner or later lead to controversies and serious commercial aberrations.

In case poor power factors are becoming a problem, a rational approach is to introduce a well-judged, voltage linked penalties for poor power factors rather than have kVAh tariffs.

kWh versus kVAh
When a consumer pays for electricity, the effective electricity rate he pays comprise of three components, which may not be visible in the final unitary tariffs. These components are:

  • Energy purchased from the generating stations or grid (kWh)
  • Energy loss incurred by the distribution utility (kWh)
  • Annual charges for the distribution system (this includes ROE, O&M etc.)

The last part (annual charges) are linked to the system kVA capacity. This kVA capacity determines the total demand that can be sanctioned to consumers (after considering appropriate diversity factor).

That is why it is appropriate to have a tariff based on kWh and not on kVAh. Exceeding the sanctioned kVA demand value means that the system is utilized beyond its design. This should invite a penalty as is already the case in most tariffs, and not legitimized through a kVAh tariff. This penalty can, if necessary, be extended to domestic sector as well and this will appropriately address the poor power factor problem.

A legal aspect – not to be overlooked

There may be a legal angle in case kVAh tariffs are introduced. A distribution utility cannot charge for something it has not generated or purchased. The kVAh neither represents the “value of supply”, as required by the Act nor does it represent any “energy”. In case kVAh metering is proposed, it is easy to visualize how the Regulatory Commission might view the concept and react to it.

A second legal aspect shall be controversy in the technical method in which kVAh is to be measured. Addressing all these is not an easy task.

kVAh metering may lead to abnormal voltages in the system

kVAh metering and tariffs shall tend to legitimize reactive drawls and may lead to an uncontrollable voltage situation and high loss in the distribution system.

There will always be consumers who care too little about power factors and higher energy bills. There will be a few consumers who may connect fixed capacitors causing the high voltage in the system, affecting all other consumers. There may be a few consumers who care too little and draw high reactive currents causing the poor voltage in the system. kVAh metering can do little to deter such consumers, other than bill them a bit more.

How serious is the problem we want to tackle

kVAh metering is targeted to improve the reactive current flow in the Indian distribution systems. It is worth examining how wide-spread or serious is this problem.

Those who have experience on transmission systems will know that the transmission lines carry a substantial reactive current. This is fortunately not the case for most radially operated distribution feeders. Our study shows that for a good number of distribution feeders we have selected at random from different parts of the country, the power factor is better than 0.9 lag !. A surprise finding indeed, indicating that there may be a few only with ailment that need the kVAh metering medicine .

We have also seen that most semi-urban and rural domestic loads in India have a good power factor. We have observed that voltage drops in distribution feeders are caused by long lines of low conductor sizes and not due to high reactive power flow. It needs to be recognized that distribution lines have a high resistance, and that in Indian conditions we come across HT:LT ratios of 1:5 and 1:6. Our problem lies there, and the priority lies in improving such systems, not in planning to introduce kVAh tariffs.

Rural feeders are the only ones which may have a power factor of 0.8 or less. More than 35% of the energy is consumed by this sector, and this is a sector where kVAh metering could have possibly helped (other feeders have too good a power factor). In the rural sector, with highly subsidized agriculture tariffs, what sense will a kVAh meter make.

Possibly the problem of high reactive loss has been over-imagined, which has lead the thinkers to think of kVAh metering. It is believed that technical loss in Indian distribution systems are very high. Yes, they are high compared to other countries, but much less than common perceptions about it. We have made technical loss studies throughout the country and we can separately tell you what the range of losses are. We have observations to indicate that even if reactive drawls are reduced, the saving in energy will be barely noticeable.

There are many more avenues where energy can be saved with relatively little investment. kVAh metering is not the magic solution.

How practical is the kvah proposition

Notwithstanding all the above problems, even if it is finally decided that the country must shift over from the kWh system to the kVAh system of metering, it is easy to see that thousands of crores of rupees will be required for the transition. A part-transition will not do; it has to be a complete changeover as tariffs itself will need to be changed – not at all an easy proposition.

Since kVAh meters will be tariff metering devices they will have to be tested as

per legal metrology norms. Again there is no standard definition and no standard equipment to test and measure kVAh available today. Such an equipment will have to be qualified as per the norms of kVAh measurement set herewith.

We have all seen how the present 100% metering drive is far from completion. If all meters were to be replaced to kVAh meters we can well imagine how time taking it will be to change/replace all meters (which is far more in numbers than that covered under 100% metering drive).

If at all this is so difficult a transition, if at all it will mean such a huge investment, if at all there is so much of technical ambiguity, if at all the kVAh system is neither legally or commercially sound, and if the very ailment which kVAh professes to address is not that wide-spread, kVAh metering is simply not a practical proposition.

“kVAh metering may be a great idea, but seriously aberrated both technically and commercially, and against all conceivable technical and commercial interests of consumers, utilities and the country.”


We need not imagine from where this huge sum of capital for changing kWh meters to kVAh meters will come from. We need not comment whether such a huge sum of money could have been gainfully utilized for other purposes and more important improvement of the power sector. As manufacturers of energy meters, all we see here is a bounty of business opportunity for us and we see it as an opportunity to make money if at all this kVAh metering concept is implemented.

But as citizens of this country we also see this as an unnecessary and technically incorrect move. We see this as an inappropriate method to address a problem, and we can see how much it will cost this poor country. As market leaders in metering in India, all we suggest is, the kVAh metering may be a great idea, but seriously aberrated both technically and commercially, and against all conceivable technical and commercial interests of consumers, utilities and the country.