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Cover Story | August 2016

PQ standards are mentioned, but not monitored

Anil Kadam | Senior Manager - Solution Architect (Utility Segment), Schneider Electric India

What are the regulatory and non regulatory measures that are helping the cause of maintaining power quality in India and what is the impact?

Although there are certain standards of performance for power distribution companies mentioned by the Central Electricity Regulatory Commission (CERC) and also mandated by the state electricity regulatory commissions, they are not properly monitored. I will tell you a simple reason. There is a performance indicator called SAIDI-SAIFI. SAIDI stands for Standard Average Interruption Duration Index, SAIFI stands for Standard Average Interruption Frequency Index. What it sees is how many times did a 11kV or 33 kV transformer saw interruption, 10 times in a year or 20 times in a year or 30 times in a year. How long was there no power because of interruption in it? So this is published by the distribution company on their website and is in public domain. Very few distribution companies are doing it. So, there should be enough regulatory re-sensitisation of distribution companies for supply of quality power. And you have to improve the standards of performance. Otherwise, some of the distribution companies think they have done their job, even when the power is restored within six hours after an interruption. Whereas, even one or two minutes of interruption is not acceptable in countries like Singapore. Utilities are being penalised in Singapore or US for providing non-quality power to the consumers. That means there is a huge fine and penalty which is ultimately passed on back to the consumer. There has to be a strong regulatory regime

Actually, the regulators have to act and they have to ensure what they suggest is being implemented...
In India for power supply/ distribution companies (discom) regulator´s main agenda is to protect the interest of consumers.

They don´t want any tariff hike to happen at any point in time. In fact, they would want to reduce it which is not in tune with the reality. So if distribution company wants to invest X amount of money for say power quality improvement, it has to be approved by the regulator. Ultimately any investment leads to tariff revision. Most of the times it is a very delayed procedure. How do we change this practice? Because power quality improvement is going to bring back more improved revenues to the company. So distribution companies also need to understand the fact that this will ultimately improve their ROR (Rate of Return).

That will come only when there is competition that means there are two three distribution providers...

Fully accepted. The world is more competitive and more quality-oriented. In India, an open access rule has been passed - anybody can supply power on anybody´s wire. Mumbai is already a testimony to it. Reliance is supplying power to Tata consumer through Tata wire and Tata is supplying power to Reliance consumer from Reliance wire. Both are competing in terms of price for quality power. So, only when competition comes, this will happen. I think those days are not very far from here.

What is the importance of Power Quality (PQ) and what will be the impact of inadequacies in maintaining reliable power supply on various equipment used by different categories of users?
We are talking about electrical power here. There is a set of limits of electrical properties that allows an electrical system to function in their intended manner without significant loss of performance or life. Which means adhering to the electrical parameters within their limits. Electrical power that drives the electrical load and the loads´ ability to function properly with that electrical power is subjected to the values of these properties within the limits. Because proper power electrical device - it could be a load or it could be a transmitting device or even regenerating device - they malfunction. They could fail permanently or not operate at all. So there is a loss of capital equipment and sometimes loss of even life also. So there are many causes of such poor quality of power. A few of them I shall list down.

There are a few reasons why a power quality deteriorates. One is transients, that means there are surges in the voltages in current levels of electrical power created because of transients, which happen mainly because of faults. Transient is one of the main reasons for deterioration of power quality. Interruption is the second main reason. There is a lot of load tripping happening in this country. Just they switch off the 11kV transformer and all the customers connected below are load shedded or there is a fault in a line and there is a tripping of a breaker which takes our smart brains to find out where the fault is and till then the power is not restored to the customers.

Third is sag and swell. Under voltage is called sag and overvoltage is called swell, that is variation of voltage. In India, commercial and residential customer is to be connected to 230 volts, plus or minus 10%. But sometimes, we can see sag where the voltage drops to 120 volts, that is the customer has 30-40% lower voltage and sometimes the voltage could even reach 280-270 volts, which is a surplus of 30% -40%, so such variations are very dangerous for the equipment. You might lose a complete range of consumer electronics or the appliances connected to the variation in power quality.

Fourth is continuous voltage fluctuation. The sag and the swell, up down, up down, up down, up down...
Fifth is harmonics. That means we are at 50 hertz fundamental frequency and 230 volts, but there are a lot of super imposed high frequency power AC side waves or different waves which are super imposed on this. Second harmonic it is 100, third harmonic, fourth harmonic, you can name up to 13 harmonics. So this is created by the lower loads which are connected to the power. Mostly power electronic devices or power electronic loads create this harmonic and because of harmonic created by one load another load suffers. For example, electronics might be spoilt because of the harmonics created by power electronics.

And the last one is power factor. The power factor basically finds its capability has the capacity of supplying power to the consumer. So it is ready, the power factor is the power distributing capacity of the network and a lot of things.

What are your products that could be deployed for ensuring Power quality (QoP) and how do they benefit the user industries and clients?
The base offer that Schneider provides is auditing - the types of the consumers vary, whether it is large industrial, small industrial, commercial or even large residential or sometimes small residential. We do a thorough analysis of the network in the premises, analyse the types of loads and analyse the types of sources from where the power is coming and we do an audit report to say these are power quality issues in the insulation and because of which these are the potential problems that a customer is facing. Mostly a customer calls and says we are already facing these problem(s). After that report, there comes the rectification or the mitigation of all these problems. And we provide them solutions, change of configuration of network which is passive and then we bring in a lot of active equipments. For example, the simplest offer what Schneider can provide a customer is a power quality meter. That means a metre put on the network of the consumer can measure sag-swell, voltage fluctuation, power factor, harmonics, what other harmonics are available, that is a power quality meter.

Next is, we connect all the power quality metres and create a SCADA system to centrally monitor what is the power quality level of the consumer. If you are talking of a big metal plant or an aluminium plant, having just one metre is not sufficient. Everywhere there is a major load and a major source of power and stuff like that. So, we provide a complete energy management system if you will, where there are only monitoring solutions.

Now after you have monitored, you should also control. So what we do is we provide power quality improvement equipment. For example, one of the equipment is we do manufacture various ranges of APFC (Automated Power Factor Correction) panels. Wherein the panel has a lot of capacitors inside and it has an intelligent device inside, which monitors what is the power factor of the system. If the power factor of the system goes beyond a certain limit, for example, below 0.9 or 0.95 capacitors into it, you are improving the quality. That is, the equipment is called power factor capacitors and APFC panels.

Second is, they have active filters. This filter removes the harmonic from the content of the power and then feed it to the load. That means the pollution created by the harmonic system can be removed even then. It´s a mixed product. As such, there are a lot of products to improve power quality.

Interruption, how can I help the distribution companies reduce interruption? We provide a very robust solution to a distribution company, which is part of smart grid and called ´speeder automation´. Which means it is a solution out of the consumer, but in the distribution company. Then because of feeder automation solution, I reduce interruption by quickly finding where the fault is and restoring the non-faulty parts quickly which is in seconds and then heal the systems. So, consumer is exposed to less amount of interruption.

We have a larger offer of Advanced Distribution Management Systems (ADMS), which is creating a command and control centre for a distribution company, so a city´s power distribution quality can be maintained.

What are the latest research and development outcomes that will help improve power quality?
There are a lot of products and solutions available for power quality improvement. Though implementation is very slow in the country, the emphasis for power quality is on the rise. Today ´Power to All´ is a mandate. Quality of power is the second mandate. So, 24/7 quality of power to all will really improve power quality maintenance. So I think that has to be taken more seriously by our company and all industry related bodies, and India Smart Grid Forum (ISGF) is working towards it.

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